1

Chapter 1

Changes Between Draft and Final EIS

The following changes were made to Chapter 1 between the Draft and Final EIS. Minor corrections, 

explanations, and edits are not included in this list.

Changes were made to:

• Clarify the Purposes;

• Better describe the basis for the 1984 court injunction;

• Note that a June 2009 Stipulated Agreement vacates the 1984 injunction effective when any administrative 

appeals to the Record of Decision for this Final EIS have been resolved;

• Note that the Record of Decision will be signed 30 to 90 days after issuance of the Final EIS, and not 

concurrently with it as previously planned;

• Help clarify that the overarching context for all of the alternatives is the BLM’s Integrated Vegetation 

Management policy;

• Broaden the qualifying habitat treatments under the Proposed Action to include treatments specified or 

referenced in delisting and monitoring plans for (formerly) Federally Listed species;

• Note that the decision-maker could modify the selected alternative by adding features from other 

alternatives, removing certain herbicides, or making other changes, if the environmental effects of such 

changes are reasonably discernable in the Final EIS; 

• Add a new section - Non-BLM Actions Potentially Affecting the Use of Herbicides on BLM Lands in 

Oregon - that describes Environmental Protection Agency, State, and other ongoing activities, such as 

herbicide registration and monitoring. Some of the items in this section were moved from the Cumulative 

Impacts section in the Draft EIS;

• Move the Conflicts and Consistency with Other Plans section from Chapter 4 to Chapter 1; and,

• Describe the public review process for the Draft EIS.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 2

Table of Contents

Chapter 1 - Purpose and Need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

The Need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Proposed Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Alternatives to the Proposed Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

The Purposes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Decision to be Made . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Scoping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Public Review of the Draft EIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Consultation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Related Plans and Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2007 National PEIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Resource Management Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Existing and Future Project-Level Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Non-BLM Actions Potentially Affecting the Use of Herbicides on BLM Lands in Oregon . . . . . . . . . . . . . . . . . . . . . 17

2004 Court-Ordered Buffer Around Salmon and the Settlement Agreement to 

Complete Consultation on 37 Pesticides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Potential Consultation Lawsuit Regarding 394 Pesticides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Petition to Cancel all Registrations of 2,4-D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Sulfometuron Methyl Reregistration Eligibility Decision (RED) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Oregon Priority Persistent Pollutant (P3) List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Oregon Department of Environmental Quality Toxics Reduction Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

EPA Endocrine Disruptor Screening Program (EDSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Rulemaking to Require Disclosure of All Pesticide Ingredients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Pending EPA Action to Address Pesticide Drift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Conflicts and Consistency with Other Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figures

Figure 1-1. Lands Administered by the Bureau of Land Management in Oregon...................................5

Figure 1-2. Average Annual Precipitation 1961-1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Final Environmental Impact Statement, Chapter 1: Purpose and Need

3

Chapter 1

Purpose and Need

Introduction

This Environmental Impact Statement (EIS) was prepared by the Bureau of Land Management (BLM) Oregon 

State Office to analyze, at the programmatic scale, a proposal to increase the number of herbicides1 available to 

the nine BLM districts in Oregon (Figure 1-1) for use in their existing noxious weed, invasive plant, and other 

vegetation management programs. This EIS does not analyze any specific treatments nor will the decision 

authorize specific projects. Future vegetation control projects utilizing herbicides proposed by BLM districts 

within Oregon will be subject to district or project level (site-specific) analyses and decisions under the National 

Environmental Policy Act (NEPA)2

. Those site-specific analyses will tier to this EIS and be subject to the 

limitations imposed by the Record of Decision for this EIS. This EIS does not propose or examine the use of 

herbicides specifically for livestock forage or timber production. This EIS does not propose to amend district 

Resource Management Plans (RMPs). 

In 2007, the BLM National office completed the Vegetation 

Treatments Using Herbicides on Bureau of Land Management 

Lands in 17 Western States Programmatic Environmental 

Impact Statement (PEIS) and related Record of Decision, 

making 18 herbicides available for a full range of vegetation 

treatments in 17 western states. In western states other than 

Oregon, the BLM is implementing the Record of Decision 

for the PEIS by directly tiering to it at the field office 

level. However, the BLM in Oregon is currently unable to 

implement the 2007 Record of Decision because of a 1984 

U.S. District Court injunction issued following a finding in 

Northwest Coalition for Alternatives to Pesticides, et al. v. 

Block, et al. (Civ. No. 82-6273-E) that the BLM had not prepared Worst Case Analyses for the herbicides being 

used at that time. The injunction was subsequently modified by the court in November 1987 (Civ. No. 82-6272-

BU) after preparation of the missing analyses.3 The injunction permits the use of only four herbicides4, and limits 

their use to the control and eradication of noxious weeds.5

1 The term “herbicide” is used in this EIS to mean active ingredient (a.i.), and not trade name or formulation.

2 BLM policy does not permit herbicide use under a categorical exclusion. A site-specific Environmental Assessment or 

Environmental Impact Statement must be prepared.

3 Worst Case Analyses are no longer required by NEPA.

4 2,4-D, dicamba, glyphosate, and picloram

5 The injunction was amended June 22, 2009 to permit the use of glyphosate to kill tanoak to control Sudden Oak 

Death in 2009 and 2010, and to control European beach grass in 2009 to 2011 in the New River Area of Critical 

Environmental Concern where it is encroaching on suitable habitat for three Special Status plants (US District Court 

2009). The amendment also vacates the injunction upon resolution of any administrative appeals to the Record of 

Decision for this EIS.

Terminology:

Invasive plants (or weeds) are non-native aggressive 

plants with the potential to cause significant damage to 

native ecosystems and/or cause significant economic 

losses. 

Noxious weeds are a subset of invasive plants that are 

county-, State-, or Federally- listed as injurious to 

public health, agriculture, recreation, wildlife, or any 

public or private property. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 4

This Oregon-wide EIS has been prepared primarily to address BLM herbicide use in Oregon in a single 

programmatic document, because, unlike the other western states, many of the herbicides proposed for use have 

not been used on Oregon BLM lands in the past 20 years. Prior to the 2007 Record of Decision for the PEIS, 

western states other than Oregon were using up to 20 different herbicides to meet a full range of vegetation 

management objectives. In those states, the Record of Decision removed six and added four for a net decrease 

of two herbicides. The action alternatives in this EIS would make up to 18 herbicides available to a program 

currently limited to four, and currently limited to noxious weed control. This EIS tiers to the PEIS and 

incorporates its entire analysis as Appendix 1. For the most part, pertinent analysis and conclusions of the PEIS 

are summarized into the body of this EIS for easier reference. This EIS also provides additional details about 

proposed herbicide use (and related effects) in Oregon. 

This is a Final EIS. The Record of Decision, expected to be signed in 30 to 90 days, will be subject to a 30-day 

appeal period before the decision can be implemented. The decision-maker for this EIS will be the Oregon/

Washington BLM State Director.

Background

The BLM manages approximately 15.7 million acres in Oregon, or about 25 percent of the land in the State. 

For the most part, these lands are either public domain lands managed under the Federal Land Policy and 

Management Act (FLPMA) or revested lands of the Oregon and California Railroad and reconveyed Coos Bay 

Wagon Road Grant Lands, specified for Department of the Interior management by the Oregon and California 

Railroad and Coos Bay Wagon Road Grant Lands Act (O&C Act) of 1937. Although these two acts provide 

for different management priorities, both result in BLM providing for various land uses and outputs, and 

accommodating various developments for the public good. These include, but are not limited to, utility corridors, 

access roads, mining, grazing, timber production, recreation, and communications sites. These human uses 

and developments, and the vegetation management in support of them, have resulted in changes to native plant 

communities. While many of those vegetation changes have been intentional and beneficial, some have occurred 

at the expense of ecosystem health. These include the expansion of noxious weeds and other invasive plants and 

the build-up of hazardous fuels. Active vegetation management can mitigate some of these undesirable changes. 

Developments such as roads, utility corridors, and recreation sites also bring with them an expectation that 

encroaching vegetation will be managed to protect investments and maintain public safety. 

Numerous laws and policies direct and authorize the BLM to manage vegetation. The FLPMA and other laws 

provide a broad vegetation management mandate. The FLPMA directs the BLM to manage public lands “in a 

manner that will protect the quality of scientific, scenic, historic, ecological, environmental, air and atmospheric, 

water resources and archeological values...” (43 U.S.C. § 1701(a)(8)). In all, over 150 different authorities or 

policies direct vegetation management on lands administered by the BLM (BLM lands). Vegetation management 

can be used to improve land health and habitat, reduce fire risk, and preserve infrastructure (PEIS: Chapter 1).

Some Federal laws specifically direct the BLM and other agencies to aggressively manage invasive plants and 

other vegetation to improve ecosystem health and reduce fire risk. In particular, two weed control acts, the 

Carlson-Foley Act of 1968 (43 U.S.C. §§ 1241-1243) and the Plant Protection Act of 2000 (7 U.S.C. § 7702), 

authorize the BLM to manage noxious weeds and to coordinate with other Federal and State agencies in activities 

to eradicate, suppress, control, prevent, or retard the spread of any noxious weeds on Federal lands. The 

Federal Noxious Weed Act of 1974 (7 U.S.C. § 2814(a)) established a program to manage undesirable plants, 

implemented cooperative agreements with State agencies, and established integrated management systems to 

control undesirable plant species. The Noxious Weed Control and Eradication Act of 2004 (7 U.S.C. § 7781) 

established a program to provide assistance through states to eligible weed management entities to control or 
5

Final Environmental Impact Statement, Chapter 1: Purpose and Need

Figure 1-1. 

Lands Administered by

the

Bureau

of Land

Managemen

t in

Oregon
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 6

eradicate harmful non-native weeds on public and private lands. The Public Rangelands Improvement Act of 

1978 (43 U.S.C. § 1901(b)(2) requires the BLM to manage, maintain, and improve the condition of the public 

rangelands so that they become as productive as feasible. The Healthy Forests Restoration Act of 2003 (16 U.S.C. 

§§ 6501-6591) directs the BLM to take aggressive actions to reduce catastrophic wildfire risk on public lands, and 

places an emphasis on protecting adjacent at-risk communities.

State and County laws also provide requirements for vegetation management. State laws require the State and 

private landowners to cooperate on noxious weed control, and give the State authority to declare noxious weed 

emergencies that require landowners to immediately control specified weeds (ORS 570-500). The Oregon 

Department of Agriculture takes the lead in identifying and setting priorities for noxious weed control. The 

Oregon Department of Agriculture coordinates closely with Federal and local entities and private landowners and 

often does the actual control work on BLM and other lands under cooperative agreements. BLM’s participation in 

these coordinated efforts helps keep weeds on BLM lands from invading neighboring lands, and vice versa.

Vegetation management to meet FLPMA’s public lands management policies and to satisfy the mandates of 

other laws, policy, and resource management plans takes place annually on thousands of acres of BLM lands 

in Oregon. While the emphasis for noxious weeds is on prevention, control measures for noxious weeds are 

conducted on 22,000 acres annually using mechanical, biological, manual, fire, herbicides, and other methods. 

Similarly, the BLM and/or its cooperators manage vegetation on thousands of acres per year to restore forest and 

rangeland health; provide sustainable habitat for Federally Listed6 and other Special Status species7, and other 

plants and animals; reduce the risk of wildland fire; and, provide for safe use and access to a variety of authorized 

developments. For these treatments, a full range of non-herbicide treatment methods are described in existing 

resource management and related plans, have been analyzed in existing NEPA documents, and are currently in 

use to achieve vegetation management objectives (Appendix 6).8 However, for herbicide use, the BLM in Oregon 

is limited by the 1984/87 U.S. District Court injunction to the use of four herbicide active ingredients: 2,4-D, 

dicamba, glyphosate, and picloram for noxious weed control only.

The Need

Invasive plants are continuing to spread at an increasing rate, and for many species, there is no effective means 

of control currently available to the BLM in Oregon. The ability of non-herbicide methods to effectively meet all 

vegetation management objectives is limited. Most non-herbicide treatments are generally more expensive than 

the herbicide treatments, and are limited by access requirements such as slope; many species simply cannot be 

controlled with manual, mechanical, biological, or other non-herbicide treatments because their roots are deep and 

readily re-sprout; they are in areas where soil disturbance is not acceptable; access limitations prevent treatment; 

or, they would simply reseed into disturbed sites. For many noxious weeds, the four herbicides currently available 

to the BLM in Oregon do not result in effective control.

6 Listed as threatened or endangered under the Endangered Species Act.

7 Special Status species include Federally Listed and proposed for listing as threatened or endangered, and Bureau 

Sensitive species.

8 Currently used non-herbicide methods are also discussed in detail in the Final Vegetation Treatments on BLM Lands in 

the 17 Western States Programmatic Environmental Report (PER), which is available on the EIS website.
Final Environmental Impact Statement, Chapter 1: Purpose and Need

7

In spite of an aggressive Integrated Vegetation Management program using all available treatment methods, 

invasive plants are spreading, habitats are being degraded, and fuel buildup is increasing. About 1.2 million of the 

15.7 million acres of BLM lands in Oregon are currently infested at some level9 with noxious weeds, and at least 

5 million more are infested with other invasive plants. They are continuing to spread at an estimated rate of 10 

to 15 percent per year (Appendix 7), increasing adverse effects to various valued resources. Ecological damage 

from extensive noxious weed infestations is often permanent. Adverse effects include displacement of native 

plants; reduction in habitat and forage for wildlife and livestock; loss of Federally Listed and other Special Status 

species’ habitat; increased soil erosion; reduced water quality; reduced soil productivity; reduced wilderness and 

recreation values; and, changes in the intensity and frequency of fires (USDA 2005a). Invasive plants also spread 

to adjacent non-BLM lands, increasing control costs for affected landowners and degrading land values. 

There are also specific management situations where native and other non-invasive vegetation is going 

untreated or only partially treated because available vegetation management methods are inefficient or costly. 

The management of encroaching vegetation within road, power line, pipeline, and other rights-of-way and 

developments is being conducted with non-herbicide methods at a higher cost on BLM lands than on adjacent 

non-BLM lands where herbicides are available. The additional costs and reduced effectiveness ultimately affect 

utility subscribers and/or subtract from funds available for other vegetation treatments. Mechanical methods can 

also spread invasive plants. Western juniper is spreading into other native shrub/grass communities, capturing 

available soil water, and altering soils in ways that inhibit retention and reestablishment of native plants in those 

communities. The plant pathogen Sudden Oak Death is getting a foothold in southwest Oregon, threatening to kill 

tanoaks and other plants in the State, and leading to plant quarantines on a variety of nursery plants.

To better meet BLM’s noxious weed and other vegetation management responsibilities, there is an underlying 

need for more effective vegetation control measures.

Proposed Action

Because all other known non-herbicide methods are available and being used to the extent practicable within existing 

funding and capabilities, the Need for more effective control measures translates to a proposal and alternatives 

to make more herbicides available10 for use on public lands administered by the BLM in Oregon. The Proposed 

Action11 would make 13 herbicides available to the BLM west of the Cascades and 16 herbicides available east of 

the Cascades12 (Table 2-2 in Chapter 2) in order to better meet their noxious weed and other vegetation management 

responsibilities. These include the four herbicides currently available for noxious weed control.

The proposed herbicides are all included within the 18 herbicides approved in 2007 for use by the BLM in the 

other 16 western states. Uses would be in compliance with the PEIS Mitigation Measures and Standard Operating 

Procedures adopted for use in the 17 western states by the Record of Decision for the PEIS (see Appendix 2), as 

well as by current Department of the Interior and BLM Integrated Vegetation Management policies and priorities. 

All herbicide uses would comply with all applicable laws and restrictions, and would only be used for the lands 

and uses for which they are labeled and registered with the State of Oregon.

9 Ranging from monocultures to a few plants per acre.

10 Actual use would depend upon subsequent district or project level analyses and decisions under NEPA.

11 The Proposed Action is Alternative 4; see Chapter 2 for description of the alternatives.

12 Districts west of the Cascades are Salem, Eugene, Roseburg, Coos Bay, and Medford. Districts east of the Cascades 

are Lakeview (including the Klamath Falls Resource Area), Prineville, Burns, and Vale.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 8

Selection of the Proposed Action would allow the BLM to choose from 13 or 16 herbicides (west and east of the 

Cascades respectively):

• To treat noxious weeds and other invasive plants as necessary to meet Integrated Vegetation Management 

objectives;

• To treat any vegetation to meet safety and operation objectives in administrative sites, recreation sites, and 

rights-of-way;

• To treat any vegetation as needed to control pests and diseases in State-identified control areas, such as 

Sudden Oak Death in southwest Oregon; and,

• To treat any vegetation to achieve habitat goals specified in approved Recovery Plans or other plans 

specifically identified as part of recovery or delisting plans, Conservation Strategies, or Conservation 

Agreements13 for Federally Listed or other Special Status species.

The overarching context for all of the alternatives is the BLM’s Integrated Vegetation Management policy. For 

invasive plants, this policy emphasizes prevention of noxious weeds and other invasive plants as the first line 

of defense. Under this policy, the BLM uses a variety of prevention methods including employee and public 

education, requiring weed-free seed in restoration and other revegetation projects (USDI 2006c), encouraging 

weed-free hay for use by pack stock, and cleaning project vehicles and other equipment before it enters BLM 

managed lands. Integrated Vegetation Management policy also requires the use of cost-effective methods that 

pose the least risk to humans, natural and cultural resources, and the environment (USDI 2007c). See Integrated 

Vegetation Management in Chapter 3 for additional detail.

Alternatives to the Proposed Action

Using a broader array of herbicides would positively affect the BLM’s ability to meet its various vegetation 

management responsibilities, but could potentially expose the environment to negative effects from the herbicides 

themselves. Alternatives to the Proposed Action seek to examine different mixes of these positive and negative 

effects by considering various numbers of herbicides and considering different mixes of management objectives 

for which these herbicides could be used. The action alternatives range from making 12/13 herbicides available 

(west/east of the Cascades) for invasive plants and pest and disease control only (Alternative 3), to an alternative 

that examines the use of all 18 herbicides analyzed in the PEIS and approved for use in the other 16 western 

states for all vegetation treatment needs except those specifically designed to improve livestock forage or timber 

production (Alternative 5). A No Action Alternative (Alternative 2) and a “no herbicides” Reference Analysis are 

also examined.

The Purposes

The Purposes are objectives to be achieved by the Proposed Action and the other action alternatives. The 

Purposes include the issues identified during scoping. No alternative would meet all Purposes completely. The 

selected alternative will be the one that the Oregon/Washington BLM Director determines meets the Need and 

best meets the Purposes.

13 Conservation Strategies and Agreements are explained in Chapter 2.
Final Environmental Impact Statement, Chapter 1: Purpose and Need

9

1. Control invasive plant species to protect native ecosystems and the flora and fauna that depend on them.

Although current management efforts strive to prevent the introduction of weeds and control existing infestations, 

noxious weeds continue to spread at an estimated rate of 10 to 15 percent per year on BLM lands due in part 

to limited funding and lack of effective control methods. An estimated 1.2 million acres of the 15.7 million 

acres of BLM lands in Oregon are currently infested with State-listed noxious weeds, and approximately 5 

million more are infested with other invasive plants (mostly cheatgrass) (Appendix 7). Invasive plants crowd 

out native and other non-invasive plants; reduce habitat and forage for wildlife (including Federally Listed and 

other Special Status species) and livestock; increase soil erosion; reduce water quality; and, alter soil chemistry 

and productivity. As of June 2010, the Oregon State list of noxious weeds includes 120 species (Appendix 7: 

Table A7-1). These are a subset of invasive plants deemed so potentially harmful that the Oregon Department 

of Agriculture has a program “to protect Oregon’s agricultural industry and natural resources by preventing and 

limiting the spread and impact of invasive exotic plant species (noxious weeds) which displace and compete with 

native and other non-invasive plant species. These invasive plants affect all Oregonians directly or indirectly 

through impacts on agricultural and forest economies and on other resources such as fish, wildlife, recreation and 

overall watershed health” (ODA 2009a). The economic impact of invasive plants is substantial. A 2008 report 

prepared for the Oregon Invasive Species Council estimates the production losses, fire damage, and control costs 

for just 21 of the noxious weed species in Oregon to be $120 million per year, and estimates the annual cost of 

invasive plants in Portland, Oregon to be $10 to 31 million per year (Cusack and Harte 2008:1).

The BLM manages a wide variety of unique and irreplaceable ecosystems in Oregon from native grasslands 

in eastern Oregon to old growth forests in western Oregon. The BLM manages some of the only intact habitat 

for some wildlife and plant species found in Oregon such as sage grouse, northern spotted owls, Malheur wirelettuce, and Kincaid’s Lupine. In addition to the importance of keeping these larger landscapes free of noxious 

and invasive weeds is the additional challenge of preventing the spread of these plants into the many specially 

designated areas on BLM lands in Oregon such as Wilderness, Wilderness Study Areas, Wild and Scenic Rivers, 

Research Natural Areas, Areas of Critical Environmental Concern and National Monuments. 

Preventing noxious and invasive species from entering BLM lands that are currently weed free and from entering 

specially designated areas is of critical importance not only to the species that depend on these unique systems but 

to the broader objective of promoting and maintaining biological diversity and ecosystem health.

2. Protect the safety and function of BLM and other authorized infrastructures by controlling encroaching 

native and other non-invasive vegetation. 

Human developments also create a need to manage native and other non-invasive vegetation. Safe campground 

use is hampered by native plants like stinging nettles and poison oak, vegetation growth along roads breaks up 

pavement and reduces sight distances, and vegetation growing into power lines, transmission towers, and other 

BLM-managed or authorized improvements hamper function and become a danger to the structures themselves. 

Public and private improvements bring obligations to provide for safe access and to protect taxpayer and 

cooperator investments. Currently, management of encroaching native vegetation on BLM lands in Oregon relies 

exclusively on manual, mechanical, cultural, and other non-herbicide control methods. These methods are often 

less effective and/or more costly than using herbicides. For example, if herbicides were available to treat cut tree 

stumps under power lines so they would not re-sprout, herbaceous shrub species would begin to dominate these 

sites, substantially reducing the need to do regular tree cutting and other vegetation control treatments.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 10

3. Manage native vegetation to provide sustainable habitats for wildlife, fish, and native plants, particularly 

those included in the Special Status Species Program.

Decades of fire suppression, human uses, climate change, and other factors have altered the structure of native 

plant communities even in areas without invasive plants. For example, fire suppression has resulted in a manyfold increase in the number of western junipers in eastern Oregon when compared with historic levels. Western 

juniper uses soil moisture to the detriment of surrounding native plants and stream flow. Chemicals in the western 

juniper’s dropped needles prevent many other plants from growing, resulting in increased bare ground and soil 

erosion that changes the site potential for years or decades. Even if the western juniper is removed, the site 

may no longer support the plants that were present prior to the western juniper expansion (Dysart et al. 2008). 

Sagebrush communities critical to the success of nesting sage grouse are being altered, reducing their value as 

nesting habitat. The use of herbicides could facilitate restoration of habitats for nesting sage grouse and other 

species. Encroachment of trees and shrubs into grassland meadows threaten the Federally Listed plant Cook’s 

Lomatium. BLM 6840 policy and interagency Conservation Strategies and Agreements for Federally Listed and 

other Special Status species require the BLM to manage for sustainable habitats for those species. 

4. Manage vegetation to reduce the risk that large-scale high-intensity fires will unacceptably damage 

resources and human developments.

An unnaturally high risk of wildfire in the west is attributable to many factors, but some species of invasive plants 

have particularly exacerbated this risk. On nearly one-third of the BLM lands in Oregon today, the non-native 

and invasive annual grasses cheatgrass and medusahead have replaced or significantly encroached on native 

bunchgrass plant communities (Appendix 7). Native bunchgrass communities remain relatively green throughout 

most of the summer and resist fire. Invasive annual grasses mature and dry out earlier and burn more intensely 

and far more often than the native grasses. These fires eventually eliminate shrubs in these ecosystems. The 

resultant shift and simplification of the plant community has severely reduced the diversity of the natural flora and 

fauna community. The flammability of these altered ecosystems makes them especially hazardous in the wildland 

urban interface. Currently, the herbicides available to BLM in Oregon are not effective at controlling medusahead 

and cheatgrass,14 hampering restoration efforts and endangering human developments. 

5. Cooperatively control invasive plants so they do not infest or re-infest adjacent non-BLM lands.

Neighboring landowners are negatively affected by invasive plants (including State- and county- listed noxious 

weeds) spreading from BLM lands. For example, 71 percent of Malheur County is administered by the BLM. 

The active control of dozens of species of noxious weeds and other invasive plants by private landowners and 

County weed control personnel can be frustrated by seed coming from nearby uncontrolled weed infestations on 

public lands. Productive ranches have been lost to invasive plants, and these losses can disrupt the viability of 

ranching-dependent communities. A 1993 economic study in Grant County showed the annual economic impact 

to livestock grazing was $326,000 and losses would climb to over $3.96 million [2009 dollars] without increased 

weed management (Test 1993). During scoping for this EIS, County employees, elected officials, and weed board 

members spoke out universally in favor of increased noxious weed and other invasive plant control on BLM lands. 

Further, invasive plants are most effectively controlled by groups of landowners working in a coordinated fashion. 

Currently, County Weed Boards, Cooperative Weed Management Areas, Oregon Department of Agriculture, 

and others cooperate with the BLM on jointly funded integrated weed control projects. The effectiveness and 

14 Cheatgrass cannot be sprayed under current direction even if an effective herbicide were available, because it is not 

listed as a noxious weed.
Final Environmental Impact Statement, Chapter 1: Purpose and Need

11

efficiency of these projects is compromised for all concerned when the BLM cannot use the same tools being 

used by the rest of the cooperators. The problem is not just that County and State weed control personnel must 

switch to BLM-approved herbicides at the property line. Sometimes they must completely stop vegetation control 

efforts because it is often not practical to change to a different control method at each property line. Without the 

appropriate herbicides and cooperative efforts, adjacent landowners will continue to shoulder the burden of weed 

control while seed sources expand on adjacent public lands. In addition, cooperating with other landowners also 

helps prevent the spread of weeds onto public lands.

6. Prevent herbicide control treatments from having unacceptable adverse effects to applicators and the public, 

to desirable flora and fauna, and to soil, air, and water.

The use of herbicides in wildland settings is not without risk. Although many of the herbicides proposed for use 

in this EIS are less toxic than many household products,15 their application can put non-target plants, animals, 

applicators, and the public at risk. Additionally, there may be adverse effects to soil organisms and water. In 

general, having more herbicides available increases the likelihood of successfully controlling the target species 

while minimizing the effects to non-target plants and other species (USDA 2005a:4-18). The benefits of more 

options include: 1) reduced potential for herbicide resistance; 2) increased potential for finding an appropriate, 

cost-effective, site-specific treatment; 3) more efficient application of all control methods; and, 4) use of 

(generally) newer, less toxic herbicides. These in turn lead to lower human and ecosystem risk.

Non-herbicide treatments have risks as well. For example, mechanical treatments can break down soil structure, 

increase compaction, create dust, increase siltation in nearby streams, damage desirable as well as undesirable 

plants, and potentially re-create the site disturbance that facilitated the invasive plant issue in the first place. 

Mechanical methods also make noise, use fossil fuels, and raise worker safety concerns. Repeated chainsaw 

cutting of woody vegetation under power line rights-of-way, for example, can increase worker injury risk. 

7. Control plant pests and diseases by removing their native plant hosts when necessary to meet Oregon 

Department of Agriculture-identified control objectives.

Pests and diseases can threaten native plant species and the plant communities of which they are a part. These pests 

and diseases are most likely to take the form of insects and pathogens. If not contained, these agents can spread 

geographically by various dispersal mechanisms as well as by human movement of plant products. Many of Oregon’s 

plants are also used by the nursery industry and transported worldwide. An uncontrolled infestation of a serious pest 

could lead to a quarantine affecting the host and related plants. When these events happen, the Oregon Department 

of Agriculture declares it a State priority and identifies control areas. Although control efforts typically utilize 

insecticides, fungicides, traps, and other non-herbicide means (which are currently available to BLM), sometimes 

control strategies include killing the host vegetation around the pest population. The efficiency and success of such 

control can depend on the herbicide used. Sudden Oak Death control is an example of such a strategy.

Sudden Oak Death was first detected in southwest Oregon in 2001, where it was killing tanoak, and infecting 

rhododendron and evergreen huckleberry on nine sites totaling 40 acres. The Oregon Department of Agriculture 

quarantined the area and the Forest Service, BLM, private forest managers, and the Oregon Department of 

Agriculture have worked aggressively since 2001 to control this disease by, in part, removing host tanoak from 

around known infestations. This job is not as effective without herbicides; tanoak is a prodigious sprouter and 

sprouts are readily reinfected. Despite control efforts, the disease had spread to 178 acres by 2007. However, 

specialists believe it can be brought under control with help from herbicide treatments.

15 See Table 3-11 in Chapter 3.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 12

8. Minimize treatment costs and improve treatment effectiveness, so resource and economic losses from invasive 

plants and other vegetation growth are reduced and more of the Need can be met within expected funding. 

There are substantial differences in both the cost and effectiveness of the various control methods. The 

affordability and effectiveness of hand pulling is limited to small infestations or small areas, and is only effective 

on certain species. Mobilization of heavy equipment may be more expensive than using spray equipment. 

Control of hundreds of acres of invasive grasses may be most achievable with herbicides, since ground-disturbing 

methods are often ineffective and can exacerbate the conditions that led to the problem. Finally, the use of the 

right herbicide can achieve control with one or few treatments, while some other control method may require 

annual or even multi-annual treatments. If herbicide use is avoided, it reduces the amount of control work that 

can be completed, and it reduces the area that can be treated before seed dispersal16. A purpose is to improve 

treatment effectiveness and reduce treatments costs. There is a finite amount of funding available, and savings in 

one control area can be used in another. Often the most effective long-term control is achieved by a combination 

of herbicide and non-herbicide treatments.

Decision to be Made 

The decision to be made by the Oregon/Washington BLM State Director is whether to select the Proposed 

Action (Alternative 4) or another alternative, and determine if any additional mitigation or monitoring is to be 

applied. The decision-maker may also modify the selected alternative by adding features from other alternatives, 

removing certain herbicides, or making other changes, if the environmental effects of such changes are reasonably 

discernable in the EIS. The decision will be based on the degree to which the selected alternative meets the Need

and Purposes. Because of the differences between the alternatives, the selection will effectively determine which, 

if any, additional herbicides will be available for use by the BLM in Oregon, and what vegetation management 

objectives they could be used for. 

Scoping 

Scoping is the term used to identify issues, concerns, and opportunities associated with the proposed action in an 

EIS. Public involvement in the scoping process began when the Notice of Intent to prepare an Environmental 

Impact Statement (EIS) for Vegetation Treatments Using Herbicides on BLM Lands in Oregon was published 

in the Federal Register (73[121]:35408–35409) on June 23, 2008. The Notice of Intent announced that this 

EIS would evaluate the effects of using up to 18 nationally approved herbicide active ingredients for treatment 

of noxious weeds; for treatment of invasive vegetation and other weeds in administrative sites, recreation sites, 

and rights-of-way; for treatment of forest pests and diseases; and to achieve non-commodity landscape health 

objectives. The Notice of Intent indicated that the BLM was seeking comments to help identify the relevant 

issues and environmental concerns, identify possible alternatives, and help determine the scope of this EIS. The 

Notice of Intent was also posted to the project website at http://www.blm.gov/or/plans/vegtreatmentseis/, and a 

press release was mailed to media outlets across the State, including print, radio, and broadcast media. At the 

same time, approximately 17,000 postcards were mailed out to individuals, groups, government agencies, and 

tribes identified from Oregon BLM districts and Oregon National Forests’ “interested public” lists as potentially 

interested in this EIS. These postcards, in addition to announcing the project and asking recipients if they wished 

to be on the project mailing list, noted there would be public meetings across the State in July to solicit ideas for 

issues (identified herein as Purposes) and alternatives to consider in this EIS.

16 As noted in the Noxious Weeds and Other Invasive Plants section in Chapter 4, the time between easily recognizable 

flowering and seed set can be very short, and BLM districts can be more than a million acres.
Final Environmental Impact Statement, Chapter 1: Purpose and Need

13

The scoping period closed July 28, 2008. During the scoping period, the BLM held 12 public scoping meetings 

in Oregon, one at or near each of the nine BLM District Offices and in Klamath Falls, Baker City, and Portland, 

to describe the proposal and solicit ideas for issues and alternatives to be considered in this EIS. Approximately 

40 non-BLM persons attended these meetings and most contributed comments verbally. Eighty scoping “letters” 

were also received during or shortly after the scoping period via letters, postcards, email, phone calls, and via the 

comment page on the project website. These letters helped the BLM define the alternatives to be considered and 

the eight Purposes to be addressed in this EIS and used by the decision-maker.

In addition to scoping comments, the BLM received postcards or emails from approximately 1,200 persons or 

groups asking to be on the project mailing list. Nine agencies, including the Oregon Department of Agriculture 

and the Bonneville Power Administration, received written and phone invitations to be formal cooperators with 

the BLM in the preparation of this EIS. Although they were supportive of the Proposed Action, all declined. 

In addition, 13 American Indian Tribes received letters explaining the project and the potential for effects to 

significant gathering areas and other resources, and extending an invitation to initiate government-to-government 

consultation. Follow-up phone calls to these tribal governments were made by the BLM districts reiterating these 

messages (see the Paleontological and Cultural Resources section in Chapter 4 for more detail about Tribes).

Public Review of the Draft EIS

On October 2, 2009, all of the persons who asked to be on the mailing list, sent scoping comments, or are required 

to get Environmental Impact Statements because of their positions (e.g., elected officials), were sent either a 

Draft EIS, Summary, Compact Disk, or email advising them that the Draft EIS was posted on the project website, 

depending upon the preference they stated when they asked to be on the list. The default document was a printed 

copy of the Summary if no choice was specified. The public comment period for the Draft EIS started with a 

Federal Register notice (74[190]:50986–50987) published on October 2 and ran through December 1, 2009. 

Agencies, officials, and the public were invited to comment of the Draft EIS. During the 60-day public comment 

period, 803 communications were received in the form of letters, postcards, and emails (collectively referred 

to as letters). The BLM continued to accept and process issues in letters received between December 2 and the 

completion of public comment analysis on January 6, 2010. During this time, the BLM received and processed an 

additional 240 letters of comments. 

Letters were received from a variety of interests including individuals, organizations (including watershed 

councils), businesses, and Federal, State, and local (including soil and water conservation districts) government 

agencies. Letters were received from 10 states, as well as from India, but the majority of letters originated from 

Oregon. Substantive comments were identified, summarized, and combined into 312 unique comment statements. 

Responses were prepared, resultant new information was added to the EIS, and EIS language was clarified. 

Appendix 10 contains the comment statements and responses, organized to follow the order of the Final EIS. 

Responses to letters received from Federal, State, and local governments are included in Appendix 10, and their 

letters are displayed in their entirety in Appendix 11.

Consultation

For the PEIS, the BLM consulted with the U.S. Fish and Wildlife Service (FWS) and National Marine Fisheries 

Service (NMFS) as required under Section 7 of the Endangered Species Act (PEIS:Chapter 5 and Appendix G). 

The BLM prepared a formal initiation package that included: 1) a description of the program, Federally Listed 

species, species proposed for Federal Listing, and critical habitats that may be affected by the program; and, 2) 

a Biological Assessment for Vegetation Treatments on Bureau of Land Management Lands in 17 Western States. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 14

That Biological Assessment evaluated the likely impacts to Federally Listed species, species proposed for listing, 

and critical habitats from the proposed use of herbicides and other treatment methods, and identified management 

practices to minimize impacts to these species and habitats.

The FWS issued a Letter of Concurrence on September 1, 2006 that concurred that the proposed action as 

described in the PEIS and Biological Assessment, with all Standard Operating Procedures and PEIS Mitigation 

Measures, would not likely adversely affect any Federally Listed species under the jurisdiction of the FWS. In 

addition, the FWS recognized that any future site-specific actions carried out under the PEIS would undergo 

additional consultation as appropriate. 

 

The Biological Opinion issued by the NMFS on June 26, 2007 concluded that the proposed action as described 

in the PEIS and Biological Assessment was not likely to jeopardize the continued existence of endangered and 

threatened salmon and trout, threatened green sturgeon and threatened southern resident killer whales. Since 

the PEIS does not authorize any site-specific actions, subsequent Section 7 review on proposed site-specific 

vegetation treatments will be required. There is no incidental take17 identified or exempted by the Biological 

Opinion. If take is anticipated for site-specific treatments then the amount or extent of take will be identified 

during consultation for those proposed treatments. 

Like the PEIS, this programmatic EIS does not authorize site-specific actions or amend Resource Management 

Plans. In addition, the three action alternatives in this EIS are the same as, or subsets of, the selected alternative in 

the PEIS. Therefore, this EIS is incorporating the PEIS Biological Assessment by reference (50 CFR 402.12(g)). 

Information about Federally Listed species in Oregon and a list of the Special Status species in Oregon are 

included in Appendix 5. Informal consultation with the FWS (50 CFR 402.13), and formal consultation with 

NMFS (50 CFR 402.14), are expected to confirm and apply the PEIS consultation results to this EIS. Specific 

treatment projects that tier to this EIS will be subject to site-specific consultation as appropriate. 

Government and/or decision makers of the American Indian tribes were sent a scoping letter seeking their input 

and offering the opportunity for formal government-to-government consultation for the preparation of this EIS. 

The Bureau of Indian Affairs also received the tribal scoping letter. In total, 13 tribal scoping letters were sent and 

personal contact was pursued with each tribe.

For the PEIS, the BLM consulted with the affected State Historic Preservation Offices (SHPOs) as part of Section 

106 consultation under the National Historic Preservation Act to determine how proposed vegetation treatment 

actions could affect cultural resources. Formal consultations with the Oregon SHPO and potentially affected 

Indian tribes also may be required during implementation of projects at the local level.

Related Plans and Analyses

Other NEPA documents integral to this EIS are described below. In addition, over 8,000 pages of detailed Risk 

Assessments have been prepared to evaluate the ecological and human risk for wildland use of each of the 18 

herbicides addressed in this EIS. These Risk Assessments are adopted from the PEIS, the 2005 Forest Service 

Pacific Northwest Region Invasive Plant Program EIS (USDA 2005a), and the 1991 Final EIS for Vegetation 

Management on BLM Lands in Thirteen Western States (USDI 1991). These Risk Assessments are included in 

this EIS as Appendix 8 (uncirculated) and are further described in Chapter 3.

17 “take” means to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any 

such conduct.
Final Environmental Impact Statement, Chapter 1: Purpose and Need

15

2007 National PEIS

This EIS tiers to the June 2007 Final Vegetation Treatments Using Herbicides on BLM lands in 17 Western States 

Programmatic Environmental Impact Statement (PEIS) and its September 29, 2007 Record of Decision. The 

PEIS and its Record of Decision apply to Oregon, but implementation is limited by the current U.S. District Court 

injunction. The analysis in the PEIS is fully incorporated into this EIS as Appendix 1, and major conclusions of 

that analysis are incorporated by reference (and usually brought forward into the body of this EIS, particularly in 

Chapter 4, for easier reference by the reader and the decision-maker).

Resource Management Plans

The public lands within the nine BLM districts in Oregon are covered by 18 Resource Management Plans 

(RMPs) and accompanying environmental impact statements. The RMPs contain direction for allocated uses, 

protection for resource values, and objectives for vegetation management. The RMPs acknowledge the problem 

of noxious weeds and contain objectives for their control (Appendix 6). However, they are not prescriptive about 

control methods, tools, seasons, or other treatment parameters. The alternatives in this EIS address the herbicide 

component of these control activities. None of the alternatives in this EIS would amend any of the RMPs; they 

would only provide options to conduct activities already included in the RMPs (Appendix 6). 

In addition to direction to control noxious weeds, RMPs contain direction for, or otherwise assume, the 

management of vegetation to control hazardous fuels; improve or maintain habitat, riparian areas, and visual 

resources; maintain rights-of-way and other infrastructure; and, to meet other objectives18. Methods described 

and/or assumed to be used to accomplish this direction include: prescribed and wildland fire for resource benefits; 

manual treatments such as grubbing or pulling; mechanical treatments such as disking, chopping, cutting, and 

blading; biological controls including insects or pathogens; and, (in general) the use of herbicides. These nonherbicide methods are included in the analysis in this EIS only to the extent necessary to display the relative 

environmental differences between the proposed additional use of herbicides and the alternative methods currently 

being used. A detailed examination of non-herbicide methods is in the June 2007 Final Vegetation Treatments 

on BLM Lands in 17 Western States Programmatic Environmental Report (PER), available on the EIS website at 

http://www.blm.gov/or/plans/vegtreatmentseis/. 

Seed Orchards

In 2005, the BLM completed three Integrated Pest Management EISs covering the Tyrrell Seed Orchard in the 

Eugene District, the Horning Seed Orchard in the Salem District, and the Provolt and Sprague Seed Orchards 

in the Medford District. Those EISs propose to use several herbicides to manage native vegetation in the seed 

orchards, and those EISs included detailed analyses of that proposed use, including Ecological and Human Health 

Risk Assessments. Records of Decision were signed in December 2005 and February 2006. Those Records of 

Decision approved use of those herbicides pending the lifting of the 1984/87 District Court injunction (USDI 

2005a, b, c, 2006a, b).

In 1996, the Forest Service completed an Environmental Assessment for Pest Management for Dorena Seed 

Orchard (USDA 1996). The Dorena Genetics Resource Center, Umpqua National Forest, is located on land 

administered by the Eugene District BLM. The Environmental Assessment, which assessed risk to environmental 

18 RMPs also address vegetation management for livestock forage and timber production, but the BLM is choosing not to 

address those two topics in this EIS to simplify and clarify the analysis.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 16

and human health, proposes use of two herbicides for management of the seed orchard and nursery facilities. A 

Decision Notice was signed in March 1996. 

The herbicide use proposed by the Seed Orchard decisions is included in this EIS as part of the administrative 

site treatment acres in Alternatives 4 and 5, and the environmental effects predicted in the Seed Orchard EISs 

are included in the resource sections in Chapter 4 of this EIS. Any meaningful differences between the Seed 

Orchard analyses and this EIS are identified in this EIS, and the Seed Orchard Records of Decision will be either 

confirmed or modified by the Record of Decision for this EIS. 

Additional herbicides made available to the BLM in Oregon by the Record of Decision for this EIS would also be 

available to the seed orchards (pending district or site-specific analysis). Herbicide use at the seed orchards is not 

constrained by the limitation on “timber production” common to all alternatives.

Existing and Future Project-Level Planning

Each district has completed one or more Environmental Assessment documents describing their noxious weed 

control program. These documents are generally tiered to the 1985 Northwest Area Noxious Weed Control 

Program EIS and its 1987 Supplement (USDI 1985a, 1987), either directly or indirectly through their respective 

Resource Management Plans. The existing Environmental Assessments for Prineville, Lakeview, and Burns also 

specifically tier to the 1991 Vegetation Treatment on BLM Lands in Thirteen Western States EIS. Environmental 

Assessment treatment plans are updated annually to reflect the shifting nature of noxious weed populations and 

the control efforts needed to contain them.

This is a programmatic EIS for using herbicides as part of the vegetation management program on public lands 

administered by the BLM in Oregon, and is intended to be applicable for approximately 10 to 20 years. To 

implement the resultant decision at the project level, new site-specific analyses and documentation tiered to this 

and other applicable EISs will be completed by each district. Until those site-specific assessments are completed 

and in use, vegetation management including the use of 2,4-D, dicamba, glyphosate, or picloram for noxious 

weed control will be governed by the existing district Environmental Assessments, constrained by the Standard 

Operating Procedures and PEIS Mitigation Measures adopted by the PEIS Record of Decision.

The EIS does not set weed treatment priorities or approve projects. Specific treatment needs and resource 

protection priorities are identified in district Resource Management Plans, district weed management 

Environmental Assessments, and other site-specific plans. Prior to any specific herbicide treatment, site-specific 

analyses would be conducted, with the opportunity for public comment. These site-specific analyses would 

identify the potential effects of specific herbicide treatments. Deferring site-specific analysis of actual herbicide 

treatment proposals is consistent with NEPA, since without the ability to identify, among other things, the specific 

location of an undetermined treatment, it is impossible to identify what the potential site-specific effects of such 

a project might be. Nothing in NEPA, FLPMA, or the Resource Management Plans requires the BLM to propose 

an actual herbicide activity plan or site-specific proposals at this time; site-specific vegetation management 

proposals that include an herbicide component will be developed at a later date based on the alternative selected 

from the EIS. Finally, the acreage and herbicide application figures used for analysis purposes in this EIS are 

estimates only, made for the purposes of describing potential statewide risks and effects.
Final Environmental Impact Statement, Chapter 1: Purpose and Need

17

Non-BLM Actions Potentially Affecting the Use of Herbicides on 

BLM Lands in Oregon

2004 Court-Ordered Buffer Around Salmon and the Settlement Agreement to 

Complete Consultation on 37 Pesticides

On July 2, 2002, in a case involving the Washington Toxics Coalition and the EPA, the District Court for the 

Western District of Washington found that the EPA had not consulted with National Marine Fisheries Service 

(NMFS) regarding the potential effects to Federally Listed salmon for 55 pesticides. By December 2004, the EPA 

had completed assessments of these 55 pesticides, determining 37 were potentially harmful to these anadromous 

fish and initiating consultation with NMFS. Three of the herbicides analyzed in this EIS are among these 37 (2,4-

D, diuron, and triclopyr butoxyethyl ester (BEE)).

In January 2004, in response to the NMFS consultations having not been completed, the same court ordered buffer 

zones be applied to salmon supporting waters, noting pesticide application buffer zones are a common, simple, 

and effective strategy for avoiding jeopardy for Federally Listed salmonids. The court, however, provided for 

exceptions to the buffer strip requirement, including “programs authorized by the NMFS” (EPA 2007e), which 

includes actions that could occur under the alternatives in this EIS. The exceptions state that only a one-yard 

buffer strip is required for “Use of a pesticide undertaken as part of a specific agency action” where authorized 

through consultation with NMFS. 

In addition, a Biological Assessment has been prepared for the activities addressed in the PEIS, and herbicidespecific buffers for Federally Listed and other Special Status fish species are established in the Biological 

Assessment for the PEIS, and these have been incorporated into Appendix 5 of this EIS. Consultation on this EIS 

is underway. Suggested conservation measures include a restriction on the use of triclopyr BEE in areas where 

Federally Listed and other Special Status aquatic species may occur, and restrictions on diuron and triclopyr 

BEE where off-site drift or surface runoff may occur into habitat that supports Federally Listed aquatic species 

or species proposed for listing. These proposed restrictions are more stringent than those imposed by the Court. 

The Biological Assessment prepared for the PEIS (and incorporated into this EIS) also states that site-specific 

consultation with NMFS and/or U.S. Fish and Wildlife Service will be required for use of herbicides likely to 

adversely affect Federally Listed species, or species proposed for listing. 

Because herbicide registration consultation between EPA and NMFS had not been completed, NMFS was taken 

to court. In July 2008, a settlement was reached in NW Coalition for Alternatives to Pesticides et al. v. NMFS. 

The settlement requires NMFS to complete consultation on the 37 pesticides and to design measures that will 

minimize adverse impacts. 

Potential Consultation Lawsuit Regarding 394 Pesticides

On January 28, 2010, the Center for Biological Diversity filed notice of intent to sue the EPA for failing to initiate 

consultation with NMFS and U.S. Fish and Wildlife Service for 394 pesticides potentially affecting 887 Federally 

Listed species. The notice also alleges the EPA has violated the Migratory Bird Treaty Act by registering 

pesticides that are known to kill and harm migratory birds. The listed pesticides include 11 of those evaluated in 

this EIS (2,4-D, bromacil, dicamba, diflufenzopyr, diquat, diuron, fluridone, hexazinone, imazapyr, picloram, and 

triclopyr). The EPA had 60 days to respond (CBD 2010), although as of June 2010, no response had been issued.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 18

Petition to Cancel all Registrations of 2,4-D

On November 6, 2008, the Natural Resources Defense Council (NRDC) petitioned the EPA to revoke all 

tolerances19 and cancel all registrations for 2,4-D. As a part of the petition, NRDC asserts that the EPA did not 

consider the full spectrum of potential human health effects associated with 2,4-D in connection with EPA’s 

reassessment of the existing 2,4-D tolerances, and EPA’s ecological risk assessment including:

• information on the endocrine disrupting effects of 2,4-D;

• information on the neurotoxicity related to 2,4-D exposure;

• information that products containing 2,4-D are mutagenic;

• data showing that dermal absorption of 2,4-D is enhanced by alcohol consumption, sunscreen, and DEET, 

which the EPA’s exposure assessment failed to include; and,

• information about adverse developmental effects at doses below those included in EPA’s risk assessment 

for exposure of infants to 2,4-D in breast milk.

The EPA has sought comment on the petition, but a final decision has not been reached. The BLM will comply 

with the final decision.

EPA’s risk assessment of 2,4-D and findings on whether the tolerances for 2,4-D comply with the safety standards 

are contained in a June 2005 Reregistration Eligibility Decision (RED) document20 for 2,4-D (EPA 2005a). The 

RED determined that 2,4-D containing products are eligible for reregistration provided that: (i) current data 

gaps and confirmatory data needs are addressed; (ii) the risk mitigation measures outlined in this document 

are adopted; and (iii) label amendments are made to implement these measures. The mitigation and label 

amendments are adopted onto the labels. The additional requested data are expected in 2010.

Sulfometuron Methyl Reregistration Eligibility Decision (RED)

In the November 12, 2008 Federal Register, the EPA announced that its sulfometuron methyl RED was available 

for review and comment. In the RED, the EPA proposes to:

• prohibit sulfometuron methyl in counties with an annual rainfall of less than 10 inches;

• prohibit use within 100 feet of water; and,

• prohibit use on powdery dry soil or light sandy soil when it is predicted that there is less than a 60 percent 

chance of rainfall within 48 hours (EPA 2008b).

A final decision from the EPA has not been issued. A decision to adopt the proposed standards would particularly 

affect sulfometuron methyl application in Malheur County (in the Vale District) and Sherman County (in the 

Prineville District) where annual precipitation is 9.64 inches and 9.15 inches, respectively. Figure 1-2 shows 

average annual precipitation in the State. 

19 Tolerances are limits permitted in food or water.

20 See Chapter 3 for more information about REDs.
19

Figure 1-2. 

A

verage Annual P

recipitation 1961-1990

Final Environmental Impact Statement, Chapter 1: Purpose and Need
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 20

Oregon Priority Persistent Pollutant (P3) List

The 2007 Oregon Legislature passed Senate Bill 737, which requires the Oregon Department of Environmental 

Quality to develop a list of priority persistent bioaccumulative toxics (Priority Persistent Pollutant (P3) List) 

to guide the Oregon Department of Environmental Quality’s pollution prevention efforts. A priority persistent 

pollutant is a substance that is toxic and either persists in the environment or accumulates in the tissues of 

humans, fish, wildlife, or plants. The Oregon Department of Environmental Quality’s Final P3 List identifies 118 

toxic pollutants, divided into two categories (ODEQ 2009b). None of the 18 herbicides discussed in this EIS are 

on the P3 list; they do not meet specific toxicity, persistence, and /or bioaccumulation criteria for inclusion.

Oregon Department of Environmental Quality Toxics Reduction Strategy

The Oregon Department of Environmental Quality’s draft Toxics Reduction Strategy is expected in 2011 and aims 

to use a comprehensive, integrated, cross‐media approach to reduce the risk to human health and ecological life 

from toxic pollutants in Oregon’s environment. The draft Priority Toxics Focus List (produced during the concept 

phase of this Strategy) identifies program priorities for three of the 18 herbicides addressed in this EIS, 2,4-D, 

glyphosate, and diuron. All three will be analyzed for their effects to land quality as household hazardous wastes, 

and to water quality because they are Pesticides of Interest (see the Water Resources section for more information) 

and are on the Willamette Toxics Monitoring Program Analyte List. In addition, diuron is on the Drinking Water 

Source Monitoring Program Contaminant List.

The Proposed Action (Alternative 4) would reduce the use of 2,4-D and glyphosate. Standard Operating 

Procedures and PEIS Mitigation Measures do not allow the use of diuron near water. If these herbicides were 

identified as toxics needing further reduction, the BLM would follow any direction on these herbicides.

EPA Endocrine Disruptor Screening Program (EDSP)

Endocrine disruptors are chemicals that interact with and disrupt the hormones produced or secreted by human or 

animal endocrine systems, which regulates growth, metabolism, and reproduction. A variety of chemicals have 

been found to disrupt the endocrine systems of animals in laboratory studies, and evidence shows that endocrine 

systems of certain fish and wildlife have been affected by chemical contaminants, resulting in developmental 

and reproductive problems. Based on this and other evidence, Congress passed the Food Quality Protection 

Act in 1996, requiring that EPA initiate EDSP on materials for their potential to affect the endocrine systems of 

humans and wildlife. Materials to be tested include pesticides, commercial chemicals, cosmetic ingredients, 

food additives, nutritional supplements, and certain mixtures. EPA issued the first test orders (Tier 1 testing) for 

pesticides to be screened for their potential effects on the endocrine system on October 29, 2009 (EPA 2010). 

Testing will eventually be expanded to cover all pesticides.

Because the available laboratories and resources for screening and testing cannot handle the potentially large 

number of chemicals that may be subjected to screening and testing under the EDSP at one time, EPA needed 

to develop a strategy for prioritizing chemicals for screening. Priority was ultimately based on the chemical’s 

relatively high potential for human exposure rather than using a combination of exposure- and effects-related 

factors. The list of chemicals selected for initial screening includes pesticide active ingredients and High 

Production Volume chemicals used as pesticide inerts (EPA 2007f). Of the herbicides included in this EIS, 

2,4-D and glyphosate are included in the initial list of 67 chemicals to get Tier 1 screening. The EPA notes that 

“Nothing in the approach for generating the initial list provides a basis to infer that by simply being on this list 

these chemicals are suspected to interfere with the endocrine systems of humans or other species, and it would be 

inappropriate to do so” (EPA 2009b).
Final Environmental Impact Statement, Chapter 1: Purpose and Need

21

Rulemaking to Require Disclosure of All Pesticide Ingredients

On December 23, 2009, the EPA published an Advance Notice of Proposed Rulemaking, seeking ideas for greater 

disclosure of inert ingredients in pesticides, and inviting comments on various regulatory and voluntary steps to 

achieve this broader disclosure. The 60-day comment period was extended an additional 60 days to April 23, 

2010 (EPA 2009d). Pertinent new information will be incorporated, as it becomes available, into site-specific 

analyses.

Pending EPA Action to Address Pesticide Drift

On November 4, 2009, EPA issued proposed guidance for new pesticide labeling to reduce off-target spray and 

dust drift. The actions detailed in EPA’s draft Pesticide Registration (PR) Notice on Pesticide Drift Labeling 

are intended to improve the clarity and consistency of pesticide labels and help prevent harm from pesticide 

drift. The draft PR Notice proposes labeling statements and formats intended to improve communication of drift 

management requirements to pesticide applicators and as a result, to improve protection of people and other 

non-target organisms and sites from potential adverse effects that may be caused by off-target pesticide drift. The 

recommended statements would appear on products whose application may result in drift.

The draft PR Notice contains:

1. A general drift statement that varies according to product type. The general drift statement prohibits drift 

that could cause an adverse effect to people or any other non-target organism or site. 

2. Examples of risk-based, product-specific drift use restrictions, along with formats for presenting these 

statements on product labeling. On a pesticide-by-pesticide basis, based on individual product use 

patterns, EPA will evaluate scientific information on risk and exposure from pesticide drift. These 

assessments will help the EPA determine whether product-specific use restrictions are needed to 

protect people, wildlife, water resources, schools, or other susceptible sites from potential harm. These 

restrictions could include no-spray buffer zones, or requirements related to droplet or particle size, nozzle 

height, or weather conditions at the time of application. 

3. Guidance to applicants and registrants about the process for implementing the new statements and formats 

on product labeling. 

The EPA believes the use of these statements and formats on labels will provide users consistent, understandable, and 

enforceable directions about how to protect human health and the environment from harm that might result from offtarget pesticide drift. The comment period for the proposed guidance runs until March 5, 2010 (EPA 2009e).

The EPA had previously defined spray or dust drift as the physical movement of pesticide droplets or particles 

through the air at the time of pesticide application or soon thereafter from the target site to any non- or off-target 

site. Spray drift shall not include movement of pesticides to non- or off-target sites caused by erosion, migration, 

volatility, or windblown soil particles that occurs after application unless specifically addressed on the product 

label with respect to drift control requirements (EPA 2001c).

Conflicts and Consistency with Other Plans

The CEQ regulations (40 CFR 1502.16) require a discussion of 

...possible conflicts between the proposed action and the objectives of Federal, regional, State, and local 

(and in the case of a reservation, Indian tribe) land use plans, policies and controls for the area concerned. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 22

This EIS does not propose to amend Resource Management Plans. It examines a proposal to make additional 

herbicides available to existing vegetation management programs. Their actual use would be considered at the 

site-specific scale, and need to be consistent with the management objectives for special management areas and 

other statute and Resource Management Plan-designated direction. Use would be consistent with requirements 

and objectives stated in Resource Management Plans (Appendix 6).

Herbicide use would be consistent with EPA and Oregon Department of Agriculture registration. Use potentially 

conflicting with reserved treaty rights of American Indian tribes would be subject to government-to-government 

consultation. Having additional herbicides, however, would facilitate efforts to protect these areas from noxious 

weeds and other invasive plants. 

The Forest Service in Region 6 (Oregon and Washington) adopted an invasive plant control strategy in 2005 involving 

the use of ten herbicides (USDA 2005a). It is likely the two agencies would cooperate where logical control areas 

cross administrative boundaries. The two agencies already share analyses, personnel, and other information.

Alternatives 4 and 5 would specifically facilitate, not conflict with, habitat management needs described in FWS 

Recovery/Delisting Plans and interagency Conservation Strategies for Federally Listed and other Special Status 

species (Chapter 2). The availability of imazapic under Alternatives 3-5 would facilitate the reduction of fireprone invasive annual grasses in the wildland urban interface east of the Cascades and in the Siskiyou Biome, 

furthering the objectives of the 2000 National Fire Plan (USDA, USDI 2000b).

The Lane County Board of Commissioners, with the collaboration of the Oregon Department of Transportation 

has adopted a Roadside Vegetation and Last Resort Policy (resolution #09-4-8-16) which aims to reduce 

herbicide use along roads in Lane County. The Board resolution states, “...that persistent herbicide exposure is 

now recognized as hazardous and recommends a reconsideration of routine and “residual” herbicides sprays as 

a roadside maintenance practice.” Although the Proposed Action (Alternative 4) proposes to use few acres of 

“residual” herbicides for rights-of-way maintenance west of the Cascades, the resolution has the potential to affect 

some Alternative 4 roadside treatments. The resolution would not affect noxious weed treatments on BLM lands, 

even along roadsides, because residual herbicides are not proposed for noxious weed control.

A variety of local plans and Federal and State initiatives could potentially affect implementation of projects at the 

site-specific scale. Examples include the Coastal Zone Management Act, the Coastal Barriers Protection Act, and 

rural fire district hazardous fuel management plans. The action alternatives in this EIS would only make available 

additional tools for meeting vegetation management objectives already described in BLM Resource Management 

Plans, activity plans, and policy. Since Resource Management Plans already consider local plans, and since 

herbicide use and invasive plant management is already an emphasis of the Oregon Department of Agriculture and 

other departments, it is unlikely that the action alternatives would be in conflict with these local plans in a way that 

would be significant at the programmatic scale. Any differences can be addressed during site-specific planning
23

Chapter 2

Changes Between Draft and Final EIS

The following changes were made to Chapter 2 between the Draft and Final EIS. Minor corrections, 

explanations, and edits are not included in this list.

Changes were made to:

• Clarify that the action alternatives are all set in the context of Integrated Vegetation Management, and 

that all include the BLM’s emphasis on prevention, early detection, rapid response, and using the most 

appropriate methods to protect the environment;

• Change the “no herbicides” Alternative 1 to a “Reference Analysis” to remove confusion about whether it 

was being considered as a viable alternative for meeting the Need and Purposes;

• Clarify that the prohibition on “commodity” objectives only prohibits the use of herbicides specifically for 

livestock forage or timber production, which was the original intent;

• Add “other plans listed in recovery or delisting plans” to the qualifying Conservation Strategies which 

serve as the basis for qualifying habitat improvement treatments under Alternative 4 (Proposed Action);

• Make sulfometuron methyl available west of the Cascades in Alternatives 3 and 4 because it has a shorter 

half-life and fewer adverse effects than other herbicides available for treating invasive annual grasses like 

cheatgrass;

• Add additional alternatives to the Alternatives Eliminated From Detailed Study section, in response to 

various suggestions received during the public comment period that were outside the scope of the analysis;

• Change the Comparison of the Effects of the Alternatives section from a narrative summary format to a 

table comparison format, to better comply with CEQ regulations and better show the differences between 

the alternatives;

• Show the acres of high and moderate risk herbicides by alternative and resources group (birds, mammals, 

fish, human health, etc.); and,

• Remove potential mitigation measures that duplicated label requirements, Standard Operating Procedures, 

and PEIS Mitigation Measures in Appendix 2, and clarify the remainder so their objective is clear and they 

are implementable.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 24

Table of Contents

Chapter 2 - The Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

The Reference Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Elements Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Applicable Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Legal and Policy Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Standard Operating Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Mitigation Measures Adopted by the Record of Decision for the PEIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Conservation Measures for Federally Listed Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

The Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

The No Action Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

The Action Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive

Weeds and Control Pests and Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat 

Invasive Weeds plus Limited Additional Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other 

Vegetation Management Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Alternatives Eliminated From Detailed Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

No Use of Acetolactate Synthase (ALS)-inhibiting Herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

No Aerial Application of Herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Reduce Management Activities Implicated in Weed Spread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Use Vinegar, Salt, and other Household Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Increase the Use of Non-Herbicide Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Reconsider Other BLM Management Practices that Encourage the Spread of 

Invasive Plants, such as OHV Use or Policies on the use of Weed Free Feed. . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Increase Funding to Pay for Additional Non-Herbicide Control Treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Consider the Use of Different Herbicides Other than the 18 Being Considered . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Use the Same Herbicides as the Forest Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Permit the Use of All EPA Tested and Approved Herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Permit the Use of Herbicides for the Full Range of BLM Management 

Responsibilities Including Livestock Forage and Timber Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Comparison of Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

The Reference Analysis and Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Estimated Annual Treatment Acres Under Each Alternative (Table 2-4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Comparison of the Effects of the Alternatives (Table 2-5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Response of the Alternatives to the Purposes (Table 2-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

The Preferred Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Potential Mitigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Potential Mitigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Final Environmental Impact Statement, Chapter 2: The Alternatives

25

Tables

Table 2-1. Herbicide Treatments by Alternative and Treatment Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Table 2-2. Herbicides Available Under Each Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Table 2-3. Comparison of the Features of the Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Table 2-4. Estimated Annual Treatment Acres Under Each Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Table 2-5. Comparison of the Effects of the Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42-46

Table 2-6. Response of the Alternatives to the Purposes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47-49
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 26
Final Environmental Impact Statement, Chapter 2: The Alternatives

27

Chapter 2

The Alternatives

Introduction 

This Chapter presents the No Action and three action alternatives, and well as a no-herbicide Reference Analysis. The 

three action alternatives would: a) make varying numbers of additional herbicides1 available as part of the BLM’s 

existing vegetation management program for noxious weeds, invasive plants, and other vegetation, and b) make those 

herbicides available for meeting various vegetation management objectives. These action alternatives would only add 

herbicides to non-herbicide treatment methods2 already being used in the existing Integrated Vegetation Management 

programs.3 This EIS only identifies and analyzes non-herbicide treatments to the extent necessary to understand the 

trade-offs and cumulative effects of the proposal to add herbicides to the existing program. 

The alternatives in this EIS would only make the herbicides available for BLM district consideration. The 

alternatives do not address any site-specific proposal, and no project would be implemented without additional 

site-specific analysis and decision record. However, future herbicide use levels have been estimated for each 

alternative and are presented as assumptions in Chapter 3 for effects analysis.

The Reference Analysis

A Reference Analysis was included in the Draft EIS as “Alternative 1,” but calling it an alternative was 

misleading since it would not meet the Need or Purposes and thus would not be selected. It was included for 

comparison purposes, to set a baseline for the herbicide portion of the analysis. The Reference Analysis examines 

the management of vegetation 

with non-herbicide methods. Nonherbicide methods include, but are not 

limited to, fire, manual, mechanical, 

State-approved biological control 

agents, directed livestock grazing, 

and seeding and planting for control 

of invasive vegetation. Reference 

Analysis features and effects are 

displayed on tables for comparison 

purposes with the No Action and three 

action alternatives throughout the EIS. 

1 The term “herbicide” is used in this EIS to mean active ingredient (a.i.), and not trade name or formulation.

2 Currently used non-herbicide vegetation treatment methods include (but are not limited to) mechanical (e.g., mowing, 

blading, or chainsaws), manual (e.g., pulling or grubbing), fire, bio-controls (e.g., released insects or pathogens), 

directed livestock, and seeding or planting for weed control.

3 See Chapter 3 for a description of Integrated Vegetation Management and treatment methods.

Terminology:

Invasive plants (or weeds) are non-native aggressive plants with the potential 

to cause significant damage to native ecosystems and/or cause significant 

economic losses.

Noxious weeds are a subset of invasive plants that are county-, State-, or 

Federally- listed as injurious to public health, agriculture, recreation, wildlife, or 

any public or private property. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 28

Elements Common to All Alternatives

Applicable Lands

The alternatives in this EIS would apply to public lands administered by BLM in Oregon. They would apply to the 

BLM and to permit holders, lessees, cooperators, or applicants for temporary or long-term use permits on these lands. 

Legal and Policy Requirements

Federal, State, and local laws, BLM policy, resource management plans, and all herbicide label requirements 

will be adhered to. Herbicides may be used only for the objectives and type of vegetation for which they are 

registered, as displayed on the herbicide label. The herbicides must be registered with the EPA and the State of 

Oregon. Although there are over 100 different herbicide active ingredients registered in Oregon under more than 

a thousand different trade names or formulations, the 18 herbicide active ingredients (herbicides) addressed in this 

EIS are limited to the active ingredients and formulations (brands) approved (listed for use) by the BLM National 

Office. Herbicides may be applied only by BLM and/or State certified pesticide applicators.4 BLM has a policy 

against using petroleum-based adjuvants (including surfactants) or other additives. 

Standard Operating Procedures

A variety of Standard Operating Procedures for herbicide use were adopted by the Record of Decision for the 

PEIS for use in the 17 western states. Those Standard Operating Procedures, with minor edits for clarity, are 

displayed in Appendix 2 and are made a part of all alternatives. Standard Operating Procedures reduce or avoid 

adverse effects to environmental and human resources from vegetation treatment activities. They are based on 

guidance found in BLM manuals and handbooks, regulations, and standard agency and industry practices. The 

list is not all encompassing, but is designed to give an overview of practices that would be considered when 

designing and implementing a vegetation treatment project on public lands (PER:2-29). Effects described in 

this EIS are predicated on application of the Standard Operating Procedures unless a site-specific determination 

is made that their application is unnecessary to achieve their intended purpose or protection, or unless the 

parent handbook or policy direction evolves and the new direction would continue to provide the appropriate 

environmental protections.

Mitigation Measures Adopted by the Record of Decision for the PEIS

As with the Standard Operating Procedures, a variety of mitigation measures for herbicide use were adopted 

by the Record of Decision for the PEIS for use in the 17 western states. They are displayed, with minor edits 

for clarity, in Appendix 2 and are made part of all alternatives. They are generally referred to herein as PEIS 

Mitigation Measures to separate them from the potential mitigation identified as Potential Mitigation at the end of 

this Chapter. Like the Standard Operating Procedures, application of the PEIS Mitigation Measures is assumed 

in the analysis. However, for PEIS Mitigation Measures, site-specific analysis, the use of Individual Risk 

Assessment Tools (see Chapter 3), or evolution of the PEIS Mitigation Measures into handbook direction at the 

National level, would be permitted to identify alternative ways to achieve the expected protections.

4 Non-motorized application of non-restricted herbicides may be done by uncertified personnel if they are working under 

the supervision of a certified applicator.
Final Environmental Impact Statement, Chapter 2: The Alternatives

29

Conservation Measures for Federally Listed Species

The Biological Assessment for the PEIS includes Conservation Measures for Federally Listed species. In 

consideration of these Conservation Measures and other elements of the PEIS, the U.S. Fish and Wildlife 

concurred with the BLM’s finding of “not likely to adversely affect proposed or listed endangered or threatened 

species of proposed or designated critical habitat” (Record of Decision for the PEIS, Appendix C). These 

measures are included in Appendix 5, referenced within PEIS Mitigation Measures in Appendix 2, and are 

assumed to apply to those species and habitats. In many cases, these measures duplicate Standard Operating 

Procedures and PEIS Mitigation Measures in Appendix 2.

The Alternatives

The alternatives add to existing non-herbicide methods by providing a range of both the number of herbicides to 

be available for use, and the areas/treatment objectives that they can be used for. They range from Alternative 2 

(No Action) which limits herbicide use to four herbicides and noxious weeds only, to Alternative 5, which would 

permit the use of the 18 herbicides selected for use by the BLM nationally, and permit them to be used to achieve 

any management objective except livestock forage or timber production. Each alternative adds herbicides or 

uses when compared to the one preceding it. For example, all uses and herbicides permitted under Alternative 2 

are included in Alternative 3, but Alternative 3 adds additional herbicides as well as the types of plants that may 

be treated. Similarly, all treatments and herbicides included in Alternative 3 are available in Alternative 4, but 

Alternative 4 adds additional treatment objectives when compared to Alternative 3. This “adding” effect is shown 

graphically in Table 2-1, along with the types of plants and management objective they apply to. All alternatives 

exclude herbicide use specifically for livestock forage or timber production,5 and Alternatives 3 and 4 do not 

permit aerial application west of the Cascades. 

5 This is not to infer invasive plants would not be controlled wherever they occur to protect any BLM resource values, 

but to say that control would not be focused or exclusively driven by livestock or timber growth objectives, nor would 

any native vegetation be controlled specifically to favor more desirable livestock forage or timber growth. 

Table 2-1. Herbicide Treatments by Alternative and Treatment Objective

Plant type Treatment Objective

Reference 

Analysis (no

herbicides)

Alt. 2

(4 herbicides) 

No Action

Alt. 3

(12/131

herbicides)

Alt. 4

(13/161

herbicides) 

Proposed 

Action

Alt. 5

(18 

herbicides)

Noxious / 

Invasive only

Noxious Weeds √ √ √ √

Invasive Plants √ √ √

All Other 

Vegetation 

(natives and 

non-invasive 

non-natives)

Pest and Disease Control √ √ √

Right-of-Way, admin, 

and recreation √ √

Habitat in Conservation 

Strategies √ √

All other treatments √

1 West/East of the Cascades
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 30

The No Action Alternative

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Continue to use only four herbicides (2,4-D, dicamba, glyphosate, and picloram; Table 2-2), and these only 

for State-, Federal-, or county-listed noxious weeds. 6 Use only non-herbicide methods for the management of 

(non-noxious) invasive plants and other vegetation. Aerial application would be permitted west and east of the 

Cascades.

This alternative is required by CEQ regulations for comparison purposes, and is not expected to meet the Need.

The Action Alternatives

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control 

Pests and Diseases

Make available 12 herbicides west of the Cascades (2,4-D, clopyralid, dicamba, fluridone, glyphosate, 

hexazinone, imazapic, imazapyr, metsulfuron methyl, picloram, sulfometuron methyl, and triclopyr) and 13 

herbicides east of the Cascades7 (chlorsulfuron and the 12 herbicides available west of the Cascades; Table 2-2):

• To treat noxious weeds and other invasive plants as necessary to meet Integrated Vegetation Management 

objectives; and,

• To treat any vegetation, as necessary, to control pests and diseases in State-identified8 control areas, such 

as the Sudden Oak Death9 quarantine in southwest Oregon.

No aerial application would be permitted west of the Cascades.

Alternative 3 Treatment Examples 

• Treatment of cheatgrass (invasive) to reduce fire risk within the wildland urban interface or to create “green” 

fuel break zones by restoring areas to perennial, more fire-resistant native or other non-invasive species.

• Treatment of spotted knapweed (noxious) to improve the forage and cover for deer in their winter range.

• Treatment of tanoak as needed to control Sudden Oak Death in southwest Oregon.

• Treatment of medusahead (noxious) to facilitate burned area rehabilitation.

• Treatment of gorse (noxious) on roadsides.

6 The number of herbicides (four) and what they can be applied to (noxious weeds) is limited by the 1984/87 injunction. 

A June 19, 2009 court order slightly modified the injunction for 2009-2011 (see Chapter 1).

7 Based on district-identified need. See the Differences in the Number of Herbicides Proposed East and West of the 

Cascades in Chapter 3. Herbicide information is on Table 3-1 in Chapter 3. District boundaries are used to separate 

east and west. The Lakeview-Medford district boundary only nominally follows the Cascade crest but these districts are 

wholly considered east and west respectively, for the purposes of the herbicide numbers and analysis in this EIS. 

8 Oregon Department of Agriculture

9 Sudden Oak Death is the only currently known example of a treatment that would be proposed under this clause.
Final Environmental Impact Statement, Chapter 2: The Alternatives

31

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive 

Weeds plus Limited Additional Uses

Make available 13 herbicides west of the Cascades (2,4-D, clopyralid, dicamba, diuron, fluridone, glyphosate, 

hexazinone, imazapic, imazapyr, metsulfuron methyl, picloram, sulfometuron methyl, and triclopyr) and 16 

herbicides east of the Cascades (bromacil, chlorsulfuron, tebuthiuron, and the 13 herbicides available west of the 

Cascades; Table 2-2): 

• To treat noxious weeds and other invasive plants as necessary to meet Integrated Vegetation Management 

objectives.

• To treat any vegetation as needed to control pests and diseases in State-identified control areas, such as 

Sudden Oak Death in southwest Oregon.

• To treat any vegetation to meet safety and operation objectives in administrative sites, recreation sites, and 

rights-of-way.

• To treat any vegetation to achieve habitat goals specified in approved Recovery Plans or other plans 

specifically identified as part of recovery or delisting plans, Conservation Strategies, or Conservation 

Agreements (collectively referred to as Conservation Strategies) for Federally Listed10, proposed for 

listing, or Bureau Sensitive species (Special Status species). 

No aerial application would be permitted west of the Cascades.

Administrative sites, recreation sites, and rights-of-way include: 

• Linear utility transmission systems, including 

multi-purpose corridors;

• BLM and other authorized road or railroad 

rights-of-way;

• Oil and gas production or gas storage 

agreement areas and facilities;

• Geothermal, wind, or solar energy production 

areas and facilities10;

• Pumped storage hydro-power production areas 

and facilities10b;

• BLM authorized common-material or rock 

quarries and storage areas (although most 

vegetation management at such sites is for 

invasive plant control);

• Federal, State, local or tribal designated fire 

suppression equipment sites and staging areas 

including helispots;

• Cell phone, microwave, and other 

transmission sites;

• Mines;

• BLM and Forest Service seed orchards 

and progeny test sites;

• Public purpose lease areas, including 

airstrips, schools, parks, etc.;

• Interagency special management areas 

(e.g., reservoirs, military training, etc.);

• Watchable Wildlife, Adventures in 

the Past, Wild Horse Herd Viewing, 

Outstanding Natural Areas and other 

BLM designated interpretive sites;

• BLM offices, fire stations, and other 

facilities;

• Developed campgrounds, picnic areas, 

trails, overlooks, OHV staging or parking 

areas, hang-gliding areas and boat 

facilities; and,

• Other administrative and operational 

sites needed for wildfire suppression, law 

enforcement, search and rescue, inventory, 

research, resource monitoring or other 

authorized administrative uses.

10 Federally Listed means designated as threatened or endangered under the Endangered Species Act.

10b As of July 2010, there are no approved wind, solar or pumped storage facilities on Oregon BLM lands, but such projects 

 might be developed in the future. A proposed wind energy project is under consideration on the Baker Resource Area.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 32

Conservation Strategies and Conservation Agreements:

Current language at http://www.fs.fed.us/r6/sfpnw/issssp/ describes these two documents as shown here. This 

language could be updated, but the types of species included are not expected to change.

Conservation Strategies capture and condense all of the known information about the biology and ecology of a 

species including taxonomy, range, distribution, and habitat descriptions. They often identify important inventory, 

research, and monitoring information that may be relevant for further understanding of the species or for adaptive 

management purposes. They also provide information on how and when to manage a site. Strategies address 

how to manage the species and/or habitat to maintain viability or persistence of the species. They describe 

how individual sites/populations should be managed, and can also identify which sites/populations are needed 

to meet the viability, persistence, or conservation goal for the species. These documents typically cover either 

a significant portion or the entire range of the species, and may be created by one field unit, one agency, or be 

interagency in nature, but agreed upon by all administrative units the Strategy covers. Conservation Strategies 

should be coordinated with BLM State/Forest Service Regional Office planning and conservation leads. 

Conservation Agreements outline procedural assurance necessary to reduce, eliminate, or mitigate specific threats. 

Agreements are usually Memorandums of Understanding agreed upon by Federal agencies (Forest Service, BLM, 

FWS, or NOAA Fisheries) and may include States and private entities. They are typically broad-scale, giving 

general guidance on how to manage for a species. The objective of Conservation Agreements is to identify 

management that will avoid a trend towards listing under the Endangered Species Act. Agreements are typically 

voluntary non-binding documents that may be cancelled at any time. 

Alternative 4 Treatment Examples:

Consistent with Integrated Vegetation Management and other priority-setting tools, and in addition to treatments 

permitted under Alternative 3, treatments under this alternative could include:

• Control of alder encroaching on power lines.

• Treating poison oak, poison ivy, stinging nettles, or other plants that create an unacceptable human risk 

in recreation sites such as campgrounds (typically when campgrounds are closed or access to treated 

areas is restricted).

• Treatment of native sagebrush to improve sage grouse nesting habitat.

• Removing western juniper to make more water available to meet habitat goals specified in an approved 

Recovery Plan for a Federally Listed fish. 

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other 

Vegetation Management Objectives 

Make available 18 herbicides both east and west of the Cascades (Table 2-2) for the full range of vegetation 

management objectives and uses approved nationally in the Record of Decision for the PEIS and currently 

available for implementation on BLM lands in the 16 other western states except for projects specifically 

designed to improve livestock forage or timber production. Aerial application would be permitted west and 

east of the Cascades.
Final Environmental Impact Statement, Chapter 2: The Alternatives

33

Alternative 5 Treatment Examples:

Consistent with Integrated Vegetation Management and other priority setting tools, and in addition to treatments 

permitted under Alternatives 3 and 4, treatments under this alternative could include:

• Wildland urban interface community protection vegetation treatments that are designed to reduce the risk 

of wildfire to the community and/or its infrastructure developed collaboratively with the community.

• Treatments of any vegetation as needed to restore or maintain healthy, diverse, resilient, and productive 

native plant communities.

• Treatments to improve habitat for non-Special Status fish and wildlife.

Table 2-2. Herbicides Available Under Each Alternative

Herbicide Reference 

Analysis Alt 2 (No Action) Alt 3 Alt 4 (Proposed 

Action) Alt 5

Herbicides Currently Approved for use on BLM Lands in Oregon (for noxious weed control only)

2, 4-D √ √ √ √

Dicamba √ √ √ √

Glyphosate √ √ √ √

Picloram √ √ √ √

Additional Herbicides Proposed for Use in One or More of the Action Alternatives

Bromacil E √

Chlorsulfuron E E √

Clopyralid √ √ √

Diflufenzopyr + Dicamba √

Diquat √

Diuron √ √

Fluridone √ √ √

Hexazinone √ √ √

Imazapic √ √ √

Imazapyr √ √ √

Metsulfuron methyl √ √ √

Sulfometuron methyl √ √ √

Tebuthiuron E √

Triclopyr √ √ √

E: Only allowed in BLM districts east of the Cascades.

Formulations are limited to those on the BLM National list of approved herbicides.

See The 18 Herbicides section and Table 3-1 (Chapter 3) and Appendix 9 for further information about these 18 herbicides.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 34

Alternatives Eliminated From Detailed Study

No Use of Acetolactate Synthase (ALS)-inhibiting Herbicides

This alternative was suggested during scoping for this EIS. ALS-inhibitors11 work by inhibiting the enzyme 

acetolactate synthetase (ALS), resulting in inadequate supplies of the branched chain amino acids (leucine, 

isoleucine and valine). The alternative may have been suggested in part because a BLM application of 

sulfometuron methyl on a burned area in Idaho was implicated in widespread damage to adjacent private 

croplands following a dust storm (see Cumulative Impacts section in Chapter 4). Standard Operating Procedures 

designed to prevent such an event are included in this EIS.

An alternative with no use of ALS-inhibitors was analyzed in the PEIS, which is incorporated into this EIS 

as Appendix 1. It was not selected because these herbicides are potentially less harmful to plants, animals, 

and humans than other herbicide active ingredients proposed. In addition, the BLM would lose the ability to 

effectively control such aggressive species as perennial pepperweed and hoary cress, and to a lesser extent, 

saltcedar, as well as cheatgrass (Record of Decision for the PEIS:4-11). 

ALS-inhibiting herbicides are, as a group, the least toxic herbicides to the environment and human health 

evaluated in this EIS, and some of the most problematic invasive weeds are best controlled with these herbicides. 

For example, such control would require multiple applications of picloram versus a single application of imazapic 

for leafy spurge control; multiple applications of 2,4-D or triclopyr versus single applications of imazapyr for 

saltcedar control; and, multiple applications of 2,4-D or dicamba versus imazapic or metsulfuron methyl for 

perennial mustard control (PEIS: Appendix I). Excluding these five herbicides would not meet the Need and 

Purposes because of the number of weeds for which there would be no effective control, and would lead to the 

use of some herbicides with higher risks to humans and/or the environment.

No Aerial Application of Herbicides

This alternative seeks to reduce the likelihood of inadvertent application to riparian and other non-target areas, 

and reduce perceived risk. This alternative was considered in the PEIS and rejected because large expanses of 

cheatgrass and other weeds in remote areas or areas with rugged terrain would be difficult and cost-prohibitive to 

treat. In addition, using ground-based methods in rugged terrain would increase injury and herbicide exposure 

risks for workers (Record of Decision for the PEIS:4-11). However, Alternatives 3 and 4 prohibit aerial 

application west of the Cascades for a variety of reasons. The high density of streams, seeps, and other water 

bodies, coupled with dense vegetation, can make water difficult to avoid. Nearly all lands west of the Cascades 

are within source water protection areas for public water systems (Figure 4-6), and there are an uncountable 

number of individual domestic water intakes. Steep varied terrain coupled with tall vegetation (including dead 

trees) can force pilots to fly relatively high, increasing the risk of drift to water, non-target plants, and other nontarget areas, and making surface waters harder to see from the air. There are also fewer large monocultures of 

invasive plants on the west side proposed for herbicide treatments.

11 Chlorsulfuron, metsulfuron methyl, sulfometuron methyl, imazapic, and imazapyr are the ALS-inhibitors being 

considered for use by this EIS. 
Final Environmental Impact Statement, Chapter 2: The Alternatives

35

Reduce Management Activities Implicated in Weed Spread

This alternative, suggested during scoping and again by public comments on the Draft EIS, would curtail or 

restrict various management and public use activities taking place on BLM lands in order to reduce weed spread. 

Grazing, mining, logging, and off-highway vehicle use were most-often suggested as contributing to weed 

spread, but camping, hiking, wildfire control, boating, and all other activities on or near BLM lands were also 

suggested. This alternative is not considered in detail because a reconsideration of the level of various land uses 

is the purview of the land management planning process described in the Federal Land Policy and Management 

Act (FLPMA). A variety of management uses are authorized and directed by the FLPMA, by the O&C Act, and 

by other policy and direction. While these activities variously contribute to the spread of weeds (and in some 

cases, to their control), it is the role of each district’s Resource Management Plan to identify an appropriate mix 

of public uses and management practices consistent with land capability, long-term productivity, and ecosystem 

health. The potential for an activity to contribute to resource degradation (such as the spread of noxious weeds 

and other invasive plants) is one consideration in determining appropriate uses. Noxious weed control is a 

management emphasis specified in all Resource Management Plans (see Appendix 6).

It is pertinent to note that management activities are not always adverse with respect to noxious weed spread. It 

is in the interest of persons holding grazing permits, for example, to help manage their allotments to prevent their 

degradation by noxious weeds. Early-season grazing of cheatgrass can retain soil moisture and help maintain 

native and other non-invasive vegetation. A determination of the relative contribution of all BLM land uses to 

the introduction and spread of noxious weeds is beyond the scope of this analysis, thus the EIS does not suggest 

reconsideration of the level of timber harvest, grazing, OHV use, and other uses of BLM lands because they are 

implicated in invasive weed spread. 

At the project scale, BLM policy requires that when a proposed management activity (such as a timber sale or 

road construction) has a moderate or high risk for establishing noxious weeds, BLM must prescribe follow-up 

monitoring as well as identify project actions that need to be taken in order to reduce or prevent the spread of 

noxious weeds (USDI 1992b). 

Use Vinegar, Salt, and other Household Products

This alternative was suggested during scoping. There are one or more EPA-registered herbicide formulations 

that have vinegar as the active ingredient, but they are not registered with the State of Oregon and/or they are 

not included on BLM’s list of herbicides approved for use on BLM wildlands. The limited number of registered 

target plants, lack of widespread use on non-BLM lands, and relatively little experience with environmental 

effects precludes the BLM from investing in the risk assessment process for these herbicides. The process for 

proposing, analyzing, and adopting additional herbicides is outlined in Appendix 4, and a vinegar herbicide could 

be considered in the future.

Some other household products were not considered because Oregon State Law prohibits the use of any material 

to control, kill, limit, or repel plants or animals unless it is registered with the State as a pesticide and such use 

is consistent with the label. Certain household materials are registered pesticides. For example, Clorox Ultra is 

registered for killing the oospores of the root disease Phythophthora lateralis (Port-Orford-cedar root disease), 

and borax is registered for use on tree stumps to prevent the root disease Fomes annosus. Pesticide registration 

and rigorous analysis is required; being a food or household product is not necessarily evidence it would not have 

unacceptable adverse environmental effects. Salt, for example, is more toxic to parts of the environment and to 

human health than some of the herbicides included in the action alternatives. See also the Toxicity Comparison 

with Household Products section in Chapter 3.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 36

Increase the Use of Non-Herbicide Methods

This alternative proposes to meet the underlying Need for more effective vegetation control measures by 

increasing the use of non-herbicide methods such as using volunteers and hiring hand crews. This alternative 

was not considered in detail because all effective known non-herbicide methods are already available to the BLM 

in Oregon and are being used wherever practical; some plant species (such as Canada thistle and gorse) are not 

effectively controlled without herbicides because small root parts re-sprout readily; non-herbicide methods have 

site impacts such as soil disturbance and damage to non-target species; and, most manual treatments are expensive 

and thus decrease the total work that can be accomplished with available funding. Volunteers can be difficult to 

use in remote areas, on larger projects, and on weeds that are difficult to identify or remove. All of the action 

alternatives within the EIS are set in the context of Integrated Vegetation Management and existing BLM policies 

for selecting treatment methods, so non-herbicide methods will be employed to the extent practicable.

Reconsider Other BLM Management Practices that Encourage the Spread of 

Invasive Plants, such as OHV Use or Policies on the use of Weed Free Feed.

Consideration of other ways to control the spread of invasive weeds is ongoing. Many ideas, such as requiring 

weed free feed, are integral to broader programs or uses and are more appropriately left to land management 

planning or related area-wide plans such as district transportation plans or Wilderness management plans. 

Controlling the spread of noxious weeds is a consideration in all such planning – e.g., see Appendix 6 for existing 

district-specific direction regarding noxious weed control. Reconsideration of this existing direction, or of 

planning more appropriately left to different scale planning, is outside the scope of this EIS. The Proposed Action 

(Alternative 4) in this EIS assumes all other Integrated Vegetation Management policies and planning direction 

are in place and remain emphasized.

The proposed increase in the number of herbicides to control invasive plants would double the effectiveness of 

the invasive plant control program while lowering the total pounds of herbicides applied, and lowering the risks to 

human health and other elements of the environment, when compared with the No Action Alternative (Alternative 

2). Broader changes to the BLM’s strategy for controlling invasive plants, as suggested by this alternative, 

would not change the relative comparison between the alternatives in this EIS. The relative benefits of one of 

the alternatives over the other, as reflected in the analysis, would not be significantly altered, for example, by a 

change to weed free pack-stock feed, or a reduction in OHV use. While such actions might slow the spread of 

invasive weeds, they would not significantly change the need for the BLM to efficiently control some weeds with 

herbicides, and for those herbicides to be the most efficient and environmentally friendly. 

Increase Funding to Pay for Additional Non-Herbicide Control Treatments

This alternative would not use herbicides, and attempt to accomplish the vegetation management objectives 

by increasing funding to pay for vegetation treatments with more expensive non-herbicide methods. This 

alternative is not considered in detail because if additional funding were received, it would be most appropriate 

to increase accomplishments, not fund more expensive methods. The weed control need easily exceeds current 

capabilities. The analysis indicates that even with access to additional herbicides, the noxious weed spread 

rate would only be reduced by half. The “current budget trends” assumption used in the EIS permits a realistic 

comparison of alternatives at one budget level, rather than attempting to compare alternatives based on future 

budget assumptions, some of which may be speculative. Nothing in the EIS precludes the BLM from pursuing 

and receiving increased funding for weed control (although herbicide use significantly above that estimated in this 

analysis might require re-evaluation). 
37

Final Environmental Impact Statement, Chapter 2: The Alternatives

Consider the Use of Different Herbicides Other than the 18 Being Considered

This alternative would use some of the more than 100 herbicide active ingredients registered for use in Oregon 

in more than 1,000 product formulations. This alternative was not considered because herbicides used on BLM 

lands must be approved by the BLM National Office, and must, by policy, be subject to detailed ecological and 

human health risk assessments for wildland applications to help satisfy the requirements of NEPA. Neither 

the BLM nor the EPA considers the EPA registration process adequate for predicting all environmental harm in 

wildland uses. The 18 being considered in this EIS are those for which the Forest Service or BLM have current 

Risk Assessments, and that have been analyzed in the PEIS and deemed appropriate for BLM use by the Assistant 

Secretary, Lands and Mineral Management, Department of the Interior (Record of Decision for the PEIS). The 

process for proposing, evaluating, and adding additional herbicides to those approved by BLM nationally is 

described in Appendix 4. Because of the high cost of the risk assessment process, selection of ones to add 

includes a determination of broad or high-priority need.

Use the Same Herbicides as the Forest Service

This alternative seeks to reduce human health and environmental risk by excluding 2,4-D and other herbicides not 

included in the 2005 Forest Service decision for Oregon and Washington. This alternative is not considered in 

detail for several reasons.

First, the Forest Service’s Pacific Northwest Region Invasive Plant Program EIS focused only on invasive plants, 

so its focus is comparable only to Alternative 3 in this EIS (herbicides added by BLM Alternatives 4 and 5 are 

included to accomplish objectives not included in the Forest Service EIS). Eighty-three percent of the acres 

in Alternative 3 are expected to be accomplished with the same herbicides as approved by the Forest Service, 

and another 12 percent would be accomplished with 2,4-D (Table 3-3). Only 5 percent are estimated to be 

accomplished with other herbicides. In general, these additional herbicides would be applied in specialized cases 

or where weed populations had begun to show resistance to first-choice herbicides. As noted in the EIS, having 

additional herbicides does not necessarily mean more acres would be treated, but it does increase the options 

available for avoiding locally sensitive resources values. The Forest Service decided not to select 2,4-D at the 

programmatic scale. For this and other reasons, the BLM considered removing 2,4-D from one or more of the 

action alternatives and decided to retain it (see Appendix 12). 

Second, as described in Appendix 12, the removal of 2,4-D in particular would reduce the effectiveness of 

Alternative 3 at reducing noxious weed spread by at least one percent. That is, instead of reducing weed spread 

from the current 12 percent to 7 percent, the reduction would be only to 8 percent or higher. This is at least 

300,000 additional acres infested in 15 years when compared to Alternative 3 with 2,4-D.

Finally, the decision-maker can decide to exclude individual herbicides from the selected alternative. The 

possibility of such an action is described in the Decision to be Made section in Chapter 1.

Permit the Use of All EPA Tested and Approved Herbicides

This alternative would permit the use of all herbicides approved by the EPA for wildland uses. The alternative 

is not considered in detail because the United States Court of Appeals for the Ninth Circuit has found EPA 

registration procedures to be inadequate to meet the wildland applications hard look requirements of NEPA. 

Thus, the process for making herbicides available to the BLM includes an expensive Risk Assessment process. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 38

Because of the costs of such assessments, candidate herbicides are selected based on being registered for 

vegetation that BLM needs to treat, being apparently compatible with protecting wildland ecosystem values, 

and that appear to offer advantages over herbicides currently available. Risk Assessments build upon the EPA 

registration information by adding information from the scientific literature, and considering applications in 

wildland settings that appeared to be “minor” in the EPA registration process. The BLM nationally maintains 

a list of Risk Assessments it considers to adequately cover wildland use, and periodically conducts literature 

searches to check the accuracy of less recent Risk Assessments. From these, the BLM maintains a list of specific 

products known to contain only these materials and to not contain inerts and other ingredients not used by the 

BLM by policy. The list of approved herbicides and formulations is updated annually. Those approved in 2010 

are shown in Appendix 9, Table A9-2. Use of other herbicides is limited to experimental uses. The process for 

adding herbicides to the BLM National list is described in Appendix 4.

Permit the Use of Herbicides for the Full Range of BLM Management 

Responsibilities Including Livestock Forage and Timber Production

This alternative would allow the use of herbicides for the full range of multiple uses including timber and 

livestock forage production. This alternative is not considered in detail in order to simplify and clarify the 

analysis. Although the treatments addressed in the EIS are estimates of future treatments and the EIS does 

not approve treatments, the potential for relatively broad-scale treatments of native vegetation to favor 

other, sometimes non-native, vegetation could substantially broaden and complicate the analysis of effects. 

Exclusion of these treatments does not preclude the BLM from proposing and examining additional herbicide 

uses in the future.

Comparison of Alternatives

This section provides a descriptive summary of the alternatives and their environmental effects in a comparative 

form, in order to directly address the issues and provide a clear basis for choice among options. Table 2-3 

summarizes the differences between the alternatives. Table 2-4 summarizes the herbicide treatment acres 

estimated to occur under each of the alternatives. Table 2-5 compares and contrasts the alternatives on the basis 

of the environmental effects to individual resources (described in more detail in Chapter 4). Table 2-6 compares 

and contrasts the alternatives on the basis of their contribution toward accomplishment of the eight Purposes.

The Reference Analysis and Alternatives

The Reference Analysis, No Action Alternative, and the three action alternatives include a range of herbicides 

from zero to 18, include a range of management objectives herbicides can be used for ranging from none to 

everything except livestock forage and timber production. Each subsequent alternative retains the herbicides and 

objectives from the one preceding it, and adds herbicides and objectives. The three action alternatives are all 

consistent with the selected alternative in the 2007 Record of Decision for the PEIS. The herbicide objectives, 

and the additive structure, are shown on Table 2-3, Comparison of the Features of the Alternatives.
39

Table 2-3. 

Comparison of the Features of the Alternatives

Standard Reference Analysis (no herbicides) Alt. 2 (No Action) (4 herbicides) Alt. 3 (12/13 herbicides1

) Alt. 4 (Proposed Action) (13/16 herbicides1

) Alt. 5 (18 herbicides)

Noxious weeds Use non-herbicide methods. Herbicides2 available to control State, Federal, or county-listed noxious weeds.Invasive plants Use non-herbicide methods. Herbicides2 available to control any invasive plant.Pest and Disease Control Use non-herbicide methods. Herbicides2 available to control any (including native) vegetation as necessary to 

control pests and diseases in State-identified control areas.

Administrative sites, Recreation sites, Rightsof-Way

Use non-herbicide methods. Herbicides2 available to treat any (including native) 

vegetation to meet safety and operation objectives in administrative sites, recreation sites, and rights-of-way

Habitat goals in Conservation Strategies

Use non-herbicide methods. Herbicides2 available to treat any (including native) 

vegetation to achieve habitat goals specified in approved Conservation Strategies for Federally Listed or other Special Status species.

All other vegetation management 

Use non-herbicide methods. Herbicides2 available 

to accomplish any vegetation management objective except livestock forage and timber production.

1 West/East of the Cascades. See Table 2-2.2 Herbicides available in addition to existing non-herbicide methods.

Final Environmental Impact Statement, Chapter 2: The Alternatives
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 40

Estimated Annual Treatment Acres Under Each Alternative (Table 2-4)

To support the effects determinations, the acres to be treated with each herbicide, and with each non-herbicide 

method, were estimated for each alternative. Weed and other vegetation management specialists from the Oregon 

State Office and the nine district offices in Oregon estimated annual treatment levels for the next 10 to 20 years 

assuming current budget trends. Those totals are summarized on Table 2-4. 

Table 2-4. Estimated Annual Treatment Acres Under Each Alternative

Reference 

Analysis

Alt. 2 (No 

Action) Alt. 3 Alt. 4 (Proposed Action) Alt. 5

Herbicide treatments

Number of 

Herbicides

0 4 12 west /13 east1 13 west/16 east 18

Herbicide use 

limited to:

n/a Noxious Weeds 

only

Invasive Plants, 

Pest & Disease 

Control

Invasive Plants, 

Administrative 

and Recreation 

sites, Rightsof-Way, Special 

Status species’ 

habitats

Any vegetation 

management 

objective except 

Timber and 

Livestock Forage 

Production

Annual Herbicide 

Treatment Acres2

0 16,700 30,300 45,200 50,000

Non-herbicide treatments, invasive plants only (estimated annually)

Mechanical/Manual 

Methods (invasive 

plants only)

8,600 5,700 5,400

Directed Livestock 8,800 2,800 2,800

Prescribed Fire (as 

part of restoration/

control treatments)

3,700 5,700 12,500

1 West/East of the Cascades

2 Estimated herbicide treatment acres are listed by herbicide, and split east and west of the Cascades, on Table 3-3 in Chapter 3.
Final Environmental Impact Statement, Chapter 2: The Alternatives

41

Comparison of the Effects of the Alternatives (Table 2-5)

Herbicides can be uniquely hazardous, so particular attention has been given to analyzing the potential for adverse 

effects (risk) of each herbicide. Ecological and Human Health Risk Assessments have been prepared (Appendix 

8), and results have been synthesized into risk categories for various scenarios representing possible exposures 

from BLM applications. “High,” “moderate,” and “low” risk categories for each herbicide for various species 

including humans are the synthesized result of those analyses (see Chapter 3, Risk Assessments), and these risk 

categories are displayed in the tables at the end of Chapter 3. The estimated herbicide use acres and their highest 

risk categories (even if only for one exposure scenario) are included for each resource on Table 2-5, and the 

herbicides responsible for the “high” and “moderate” ratings are identified. It is important to remember these are 

“risks” based on exposures modeled in Risk Assessments, and that where these ratings are higher than 0, the ratings 

guided the development of Standard Operating Procedures and PEIS Mitigation Measures (Appendix 2) designed 

to keep actual exposures below what would potentially result in significant adverse effects. Even Federally Listed 

and other Special Status species were deemed not at significant risk because of required pre-project clearances, 

consultation requirements, and/or additional buffer requirements. 

To help describe why the BLM would accept any risk whatsoever, two other effects related to differences between 

the alternatives were also examined: 

1. The EIS includes an estimate of the current noxious weed spread rate and how the Reference Analysis 

and action alternatives might be expected to change that rate (Table 2-5). Since noxious weeds adversely 

affect most resources, the analysis contrasts the level of weed-related adverse effects between the 

alternatives. The analysis indicates that although there are some increased environmental risks associated 

with increases in the use of herbicides (substantially limited by the Standard Operating Procedures and 

PEIS Mitigation Measures), there are more adverse effects predicted from the spread of noxious weeds. 

Having more herbicides available for use would increase the options for selecting the most appropriate 

treatment to accomplish the weed control objective while minimizing risk to human health and nearby 

non-target resources including soil and water. 

2. Non-herbicide methods are not without environmental risk. Since the use of herbicides affects the acres 

treated with non-herbicide methods, adverse effects from non-herbicide treatments are estimated as well. 

For native vegetation treatments under the Alternatives 4 and 5, favorable and adverse environmental effects are 

similarly contrasted (Table 2-5). 

Response of the Alternatives to the Purposes (Table 2-6)

In Table 2-6, the environmental effects summarized in Table 2-5 (and elsewhere in the EIS) have been brought 

to bear directly on the eight Purposes identified in Chapter 1. This is probably the most important comparison 

in this section; Chapter 1 notes that no alternative would meet all Purposes completely and that the selected 

alternative will be the one that meets the Need and best meets the Purposes.
 42

Vegetation Treatments Using Herbicides on BLM Lands in Oregon

Table 2-5. 

Comparison of the Effects of the Alternatives

Resource SectionEffects Parameters Reference Analysis Alt. 2 (No Action) Alt. 3 Alt. 4 (Proposed Action) Alt. 5Noxious Weeds and Other Invasive PlantsEstimated Spread Rate in 15 years

14% 12% 7% 6% 6%

(Generally, the more herbicides available, the more likely there is one appropriate to the local situation and weed spread can be reduced.) 

Noxious weed acres in 15 years1 8.6 million 5.9 million 4.0 million 3.7 million 3.7 millionAlternative has tools to effectively control:

About 1/3 of 120 State-listed noxious weeds

104 of 120 State-listed noxious weeds

116 of 120 State-listed noxious weeds, plus other invasive plants

116 of 120 State-listed noxious weeds, plus other invasive plants

117 of 120 State-listed noxious weeds, plus other invasive plants

Native and Other Non-Invasive VegetationHerbicide risks to terrestrial plants3 None

ALS-inhibitors pose highest risk to non-target plants because of their extremely low effective dose rates. 

Acres of High risk herbicides 0 22,800 21,100 33,900 37,800Acres of Moderate risk herbicides 0 0 11,500 14,000 16,000Acres of Low risk herbicides 0 0 0 0 0Acres of 0 risk herbicides 0 0 0 0 0

Herbicide risks to aquatic plants3

Acres of High risk herbicides 0 0 700 3,900 5,100Acres of Moderate risk herbicides 0 8,500 21,000 27,600 32,200Acres of Low risk herbicides 0 8,400 6,500 10,100 10,200Acres of 0 risk herbicides 0 5,900 4,700 6,600 6,600

Non-herbicide methods More soil disturbance encourages invasive plants (highest in Reference Analysis; potential collateral damage to non-target plants). Risk proportional to soil- disturbing treatments (see Table 2-4).Invasive Plants Weeds displace native plant communities and threaten Special Status species habitats. Adverse effect proportional to weed spread. Control of invasive annual grasses helps protect at-risk sagebrush communities.Pests and Diseases (Sudden Oak Death)Native Host Control 38% reinfection of tanoak sprouts 6% reinfection of tanoak sproutsAir Quality and Climate Change Effect of Climate Change Increased CO2 will favor many invasive plants. Emissions: Partic. (tons) 936 884 982 378 378Emissions: CO2 (tons) 12,313 18,660 40,393 40,059 40,059Soil ResourcesHerbicides None

Herbicides can harm soil crusts; picloram (Alt 2), chlorsulfuron(Alt 3), metsulfuron methyl (Alt 3), and tebuthiuron (Alt 4) create short-term soil organism decline.

ALS-inhibitors can bind & travel with soils

Three soil-active persistent herbicides (bromacil, diuron, and tebuthiuron) added; bare soil susceptible to erosion.

Herbicide half-lives in soil N/A 10, 14, 47, & 20-300 days 10 to 300 days 10 to 360 days 10 to 1000 days
43

Final Environmental Impact Statement, Chapter 2: The Alternatives

Resource SectionEffects Parameters Reference Analysis Alt. 2 (No Action) Alt. 3 Alt. 4 (Proposed Action) Alt. 5Non-herbicide methods Compaction and disturbance highest with mechanical and directed livestock. Adverse effect proportional to acres treated.Invasive Plants Weeds harm soils by reducing cover (which causes erosion), and by changing chemical composition. Effect is proportional to weed spread (see Table 2-4).Water ResourcesHerbicides N/A

Herbicide pathways to water include runoff, drift, direct application, and leaching. 

Road ditches can deliver right-of-way-used persistent diuron to streams in Alternatives 4 and 5.

Known groundwater contaminants N/A 2,4-D, dicamba, picloram 2,4-D, dicamba, picloram, hexazinone 2,4-D, dicamba, picloram, hexazinone, diuron, bromacil, tebuthiuron (and diquat in Alt 5)Invasive Plants Adversely affect water resources by affecting bank stability, sediment, stream temperature, and dissolved oxygen, and pH. Aquatic invasive plants can accelerate eutrophication. Effect is proportional to weed spread.Wetlands and Riparian AreasHerbicides N/A

Picloram and glyphosate with POEA most likely to cause adverse effects (see Water Resources, Wildlife Resources, & Fish).

Picloram, glyphosate with POEA, diuron, bromacil, and tebuthiuron most likely to cause adverse effects.

Non-herbicide methods Impossible to control many reeds and other marsh plantsInvasive Plants Displace native habitat (especially critical east of the Cascades), expose stream banks to erosion, reduce shading, or clog waterways. Adverse effect is proportional to weed spread.FishHerbicide risks to fish3

Acres of High risk herbicides 0 0 0 1,400 (diuron) 1,600 (diuron, diquat)

Acres of Moderate risk herbicides 0 14,4002 (2,4-D, glyphosate with POEA) 7,000 (2,4-D, glyphosate with POEA, fluridone) 10,600 (2,4-D, glyphosate with POEA, fluridone, bromacil) 12,800 (2,4-D, glyphosate with POEA, fluridone, bromacil)Acres of Low risk herbicides 0 3,800 1,500 3,000 3,000Acres of 0 risk herbicides 0 4,600 24,400 33,200 36,700

Non-herbicide methods Mechanical and directed livestock disturbance can lead to erosion and sedimentation. Adverse effect is proportional to acres treated.Invasive Plants Habitat and food alteration, changes to aquatic plants, reduced shading, changes to vegetation-dependant insects and their proximity to water. Adverse effects proportional to weed spread.Wildlife ResourcesHerbicide risks to mammals3

Acres of High risk herbicides 0 8,500 (2,4-D) 4,000 (2,4-D) 6,800 (2,4-D, diuron) 8,900 (2,4-D, diuron)Acres of Moderate risk herbicides 0 14,300 (dicamba, glyphosate, picloram) 7,600 (dicamba, glyphosate, picloram, hexazinone, triclopyr) 14,200 (dicamba, glyphosate, picloram, hexazinone, triclopyr, bromacil, tebuthiuron) 15,700 (dicamba, glyphosate, picloram, hexazinone, triclopyr, bromacil, tebuthiuron, diquat, diflufenzopyr + dicamba)Acres of Low risk herbicides 0 0 6,000 8,100 8,200Acres of 0 risk herbicides 0 0 15,300 19,100 21,300

Herbicide risks to birds3

Acres of High risk herbicides 0 0 0 0 200 (diquat)Acres of Moderate risk herbicides 0 19,000 (2,4-D, dicamba, glyphosate) 9,900 (2,4-D, dicamba, glyphosate, triclopyr) 16,500 (2,4-D, dicamba, glyphosate, triclopyr, diuron) 19,000 (2,4-D, dicamba, glyphosate, triclopyr, diuron)

Table 2-5. 

Comparison of the Effects of the Alternatives (continued)
 44

Resource SectionEffects Parameters Reference Analysis Alt. 2 (No Action) Alt. 3 Alt. 4 (Proposed Action) Alt. 5

Acres of Low risk herbicides 0 3,800 4,900 9,400 10,200Acres of 0 risk herbicides 0 0 18,100 22,300 24,700

Herbicide risks to aquatic invertebrates3

Acres of High risk herbicides 0 0 300 (fluridone) 1,700 (fluridone, diuron) 1,900 (fluridone, diuron, diquat)Acres of Moderate risk herbicides 0 0 0 1,200 (bromacil, tebuthiuron) 1,900 (bromacil, tebuthiuron)Acres of Low risk herbicides 0 5,900 2,700 4,000 4,000Acres of 0 risk herbicides 0 16,900 29,900 41,300 46,300

Herbicide risks to insects3

Acres of High risk herbicides 0 0 0 0 0Acres of Moderate risk herbicides 0 5,900 (glyphosate) 4,900 (glyphosate, triclopyr) 9,800 (glyphosate, triclopyr, diuron, tebuthiuron) 11,000 (glyphosate, triclopyr, diuron, tebuthiuron, diquat)Acres of Low risk herbicides 0 12,300 7,200 12,200 14,500Acres of 0 risk herbicides 0 0 19,800 24,600 27,000

Non-herbicide methods Disturbance (noise) effects can exceed those from herbicides. Collateral habitat damage from mechanical or directed livestock can exceed those from herbicides, with effects proportional to acres treated with these two methods.Invasive Plants

Invasive plants decrease terrestrial, riparian, and aquatic habitat quality, decreasing wildlife numbers and species’ diversity. Adverse effect is generally proportional to weed spread, and can particularly devastate east side riparian and Special Status species’ habitats.

Control of invasive annual grasses could slow sage grouse habitat decline. 

Herbicide use on native vegetation for habitat improvement

None None None For Federally Listed and other Special Status species For all species

Livestock, Wild Horses and BurrosHerbicide risk to forage N/A Low risk of adverse effects.Herbicide risks to livestock and wild horses and burros (same as mammals)3

Acres of High risk herbicides 0 8,500 (2,4-D) 4,000 (2,4-D) 6,800 (2,4-D, diuron) 8,900 (2,4-D, diuron)Acres of Moderate risk herbicides 0 14,300 (dicamba, glyphosate, picloram) 7,600 (dicamba, glyphosate, picloram, hexazinone, triclopyr) 14,200 (dicamba, glyphosate, picloram, hexazinone, triclopyr, bromacil, tebuthiuron) 15,700 (dicamba, glyphosate, picloram, hexazinone, triclopyr, bromacil, tebuthiuron, diquat, diflufenzopyr + dicamba)Acres of Low risk herbicides 0 0 6,000 8,100 8,200Acres of 0 risk herbicides 0 0 15,300 19,100 21,300

Non-herbicide methods No adverse effects identified.Invasive Plants

Invasive plants can reduce grazing capacity 35 to 90 percent; some allotments will likely be at risk of closing because of weed-related reductions in grazing capacity in the next decade. Wild horses would move to other areas as forage capacity declines, causing livestock grazing conflicts. Adverse effects are proportional to weed spread.

Vegetation Treatments Using Herbicides on BLM Lands in Oregon

Table 2-5. 

Comparison of the Effects of the Alternatives (continued)
45

Resource SectionEffects Parameters Reference Analysis Alt. 2 (No Action) Alt. 3 Alt. 4 (Proposed Action) Alt. 5

Fire and FuelsInvasive Plants /Native Vegetation Invasive annual grasses remain major fire hazard.

Imazapic controls invasive annual grasses, allowing sagebrush habitat-protecting treatment strips, and wildland urban interface-protecting grass reduction, and restoration burns.

Roadside use, and soil-active herbicide used around developments, reduces fire risk to improvements.

TimberHerbicide & Non-herbicide methods No significant collateral damage to timber production identified under any alternative.Invasive Plants Regeneration cost increases and timber growth reductions attributable to some species (e.g., Portuguese broom); thorny species reduce access; vehicle and equipment cleaning required.Paleontological and Cultural ResourcesHerbicides N/A Human exposure in traditional tribal use areas possible (see Human Health and Safety section), increasing in Alts 4 and 5.

Herbicide and Nonherbicide treatments Potential for impacts to paleontological and cultural resources through mechanical or chemical damage, and disturbance-related erosion. Risk proportional to activity levels, but low in sites heavily disturbed by development such as roads and communication sites.Invasive Plants Adversely affect cultural uses and traditional gathering; adversely affect artifacts by decreasing cover and increasing erosion, changing soil pH. Effect proportional to weed spread.Visual ResourcesHerbicides N/A Visual effect of invasive weed control generally not noticeable 

regardless of treatment method.

Roadside treatments may be more or less obtrusive with herbicides depending on species, size, and season. Non-herbicide methods

Invasive Plants Invasive plants generally considered less visually desirable. Adverse effect proportional to weed spread.Wilderness and Other Special AreasHerbicide and Nonherbicide treatments No significant differences between alternatives. Additional herbicides especially beneficial in areas like Wilderness where mechanical treatments are rarely, if ever, allowed.Non-herbicide methods Mechanical controls usually not appropriate in Wilderness.Invasive Plants Weed spread generally compromises management objectives; adverse effect is proportional to weed spread.Recreation/Interpretive SitesHerbicides N/A Public exposure low, treating invasive plants only. Public exposure/site closures potentially higher due to ability to treat native vegetation within recreation sites.Non-herbicide methods No significant difference between alternatives.Invasive Plants Recreation enjoyment compromised by invasive plants (access, ecosystem health). Effect proportional to weed spread.Other Vegetation Better control of native vegetation, including poison oak, encroaching on developed sites.Administrative Sites, Roads, and Rights-of-WaysHerbicides N/A Little effect; noxious weed/invasive plant only. Roadside native vegetation maintenance as well as incidental noxious weed control effect.Non-herbicide methods Current direction; permit holder’s and road department’s maintenance more difficult . Would be continued where herbicides are not appropriate.Ability to control noxious weeds and competing native veg.

Noxious weed control efforts would be frustrated. Continue mowing natives.

Permit/right-of-way holders could control about 104 of 120 noxious weeds. Continue mowing natives.

Permit/right-of-way holders could control about 116 of 120 noxious weeds. Continue mowing natives.

Herbicides available to control about 117 of the 120 Statelisted noxious weeds, and to do safety and maintenance control of native vegetation. Better allows road departments to continue herbicide treatments along road corridors regardless of property boundary. 

Social and Economic ValuesConcern over the spread of invasive plants from adjacent BLM lands

Neighboring land values could be reduced, forage and other vegetation values would be harmed, and weed control costs for neighboring landowners or other agencies would increase. Adverse effects would be proportional to weed spread. Concern highest east of the Cascades.

Final Environmental Impact Statement, Chapter 2: The Alternatives

Table 2-5. 

Comparison of the Effects of the Alternatives (continued)
 46

Resource SectionEffects Parameters Reference Analysis Alt. 2 (No Action) Alt. 3 Alt. 4 (Proposed Action) Alt. 5Concern about herbicides as a threat to resource values and human health

None

Moderate concern, more west of the Cascades, tempered by importance of noxious weed control and limited acres

Moderate concern, more west of the Cascades. Acres up but total herbicide pounds and risk down when compared with Alt. 2

High concern, more west of the Cascades, because acres up, and use on admin sites, recreation sites, and rights-ofway creating unknown public exposure

Highest concern, more west of the Cascades, for reasons in Alt. 4 plus some level of unspecified treatment objectives, although most increase is east of the Cascades

Favor herbicides as a benefit to resource values

Concerns invasive plants reduce commodity, non-commodity, and non-market values, and also worried about excessive control costs. Alternative 3 reduction in weed spread perceived as substantial improvement. Alternatives 4 and 5 viewed as adding additional benefits.

Environmental JusticeMinority and low income groups herbicide exposure None Limited based on directed noxious weed/invasive plant treatments. Higher, based on general roadside and habitat treatments involving native plants.

Subsistence resources used by low income and tribes Subsistence resources are reduced by invasive plants. Adverse effect proportionate to weed spread.Implementation CostsCost per effectively treated noxious weed acre (all methods)

$565 $240 $193 $193 $193

Right-of-way/ admin/recreation treatments $2.016 million $2.016 million $2.016 million $1,085 million $1,085 millionNon-Quantified Costs Value losses and/or increased operating costs for timber, special forest products, habitat, public access, grazing, recreation, mineral, vegetation, and fuels management. Adverse effects proportional to weed spread.Non-Quantified Gains

Commodity and non-commodity values and recreation opportunities are proportionate to weed reduction.

Fire protection increased Fire protection increased and Special Status species’ habitat improvement

Human Health and SafetyHerbicide risks to worker and public health4

Acres of High risk herbicides 0 0 0 2,600 (diuron, bromacil, tebuthiuron) 3,300 (diuron, bromacil, tebuthiuron)

Acres of Moderate risk herbicides 0 8,500 (2,4-D) 4,000 (2,4-D) 5,400 (2,4-D) 7,500 (2,4-D)Acres of Low risk herbicides 0 4,600 3,200 5,700 6,300Acres of 0 risk herbicides 0 9,700 25,700 34,500 37,000

Non-herbicide methods Non-herbicide methods have risks of injury and death, including from chainsaws, prescribed fire smoke and burning, and equipment rollover.Risks from invasive plants None identified. 1 Gross acres.2 Worst case. Rating is for terrestrial glyphosate (with POEA). Aquatic-labeled glyphosate is required near water, and used in many other areas.3 Highest risk from Risk Category tables at the end of Chapter 3, not including accidental & spill exposures. Includes maximum application rates even if PEIS Mitigation Measures recommend against it. Standard Operating Procedures and PEIS Mitigation Measures mitigate or minimize risks.4 Typical rate; includes all exposure scenarios.

Vegetation Treatments Using Herbicides on BLM Lands in Oregon

Table 2-5. 

Comparison of the Effects of the Alternatives (continued)
47

Final Environmental Impact Statement, Chapter 2: The Alternatives

Table 2-6. 

R

esponse

of the

A

lternatives t

o

the

Pur

poses

Purpose/Parameter Reference Analysis Alt. 2 (No Action) Alt. 3 Alt. 4 (Proposed Action) Alt. 5

1. Control invasive plant species to protect native ecosystems and the flora and fauna that depend on them.Noxious weed annual spread rate/infested acres in 15 years

14% 12% 7% 6% 6%

8.6 million 5.9 million 4.0 million 3.7 million 3.7 million

Invasive plant impacts to ecosystems

Invasive plants displace native plants including those Federally Listed or other Special Status species, degrade or eliminate habitats, poison and expose soils to erosion, weaken stream banks thus increasing sedimentation, remove stream shading and insects that serve as fish forage, increase fire risk, clog waterways, and reduce production capacity, and reduce neighboring land values. For every resource, these effects are more adverse than the risks associated with the proposed herbicides.

Habitat Improvement

Currently only nonselective glyphosate available for medusahead removal.

Herbicides would be available to selectively control invasive annual grasses including cheatgrass and medusahead, making a combination prescribed-fire-herbicide-seeding treatment effective at removing these grasses and restoring native plants.

Alternative has tools to effectively control:

About 1/3 of 120 Statelisted noxious weeds About 104 of 120 State- listed noxious weeds About 116 of 120 State- listed noxious weeds, plus invasives About 116 of 120 State- listed noxious weeds, plus invasives About 117 of 120 State- listed noxious weeds, plus invasives

2. Protect the safety and function of BLM and other authorized infrastructures by controlling encroaching native vegetation.Control vegetation to meet safety and maintenance objectives around developments, along roads, and within rights-of-way.

Native vegetation management needs in and around developments, along BLM roads, and within rights-of-way for highways, pipelines, transmission corridors, and others would continue to be conducted with non-herbicide methods such as mowing, scraping, or armoring the site.

Herbicides could replace manual/mechanical treatments on an estimated 9,300 of the tens of thousands of acres already being treated annually, saving the BLM and permit/right-of-way holders about $1 million annually. Herbicide availability would increase permit and rightof-way holders’ efficiency by making control methods consistent with non-BLM portions of permit/right-of-way. Herbicides prevent vegetation encroachment on pavement edges, and are an efficient way to reduce fire-prone vegetation at communication sites and other non-public use developments.

3. Manage native vegetation to provide sustainable habitats for wildlife, fish, and native plants, particularly those included in the Special Status Species Program.Management of native vegetation to improve habitats.

Continue habitat improvement projects using manual, mechanical, fire, and other nonherbicide methods.

Herbicides could target specific vegetation to meet habitat objectives described in Conservation Strategies for Special Status species (est. 5,700 acres, mostly east of the Cascades)

Herbicides could target specific vegetation to meet habitat management objectives (est. less than an additional 4,800 acres when compared to Alt 4, mostly east of the Cascades)
 48

Vegetation Treatments Using Herbicides on BLM Lands in Oregon Purpose/Parameter Reference Analysis Alt. 2 (No Action) Alt. 3 Alt. 4 (Proposed Action) Alt. 5 4. Manage vegetation to reduce the risk that large-scale high-intensity fires will unacceptably damage resources and human developments. Control invasive annual grasses in the Sagebrush Steppe and lower elevations in the Siskiyou Biome to reduce wildfire impacts to habitats and communities. The reduction of fire behavior characteristics would be relatively labor-intensive, and benefits would be localized to the area treated. Glyphosate can be used on medusahead (but not cheatgrass) under Alternative 2 (No Action), but such use is limited because it also kills remnant native plants. Herbicides would increase the effectiveness of greenstripping – a proactive technique to reduce the magnitude of the cheatgrass-wildfire cycle by growing fire-resistant vegetation at strategic locations in order to slow or stop the spread of wildfires. Herbicides would be available to reduce the risk of fast-moving, intense grass-fueled fires within the wildland urban interface. Treat native vegetation around administrative sites to help keep wildfires from destroying structures and other improvements. Non-herbicide treatments include mowing, scraping, paving or rocking, or accepting a higher risk of loss to fire (and temporary loss of utility services). Permits use of persistent, soil–active herbicides to control native plants within rights-of-way and other remote sites at risk to fire. Issue is mostly east of the Cascades, or within mountaintop communication sites. (Other native fuels treatments under Alternative 5 possible but rare.) 5. Cooperatively control invasive plants so they do not infest or re-infest adjacent non-BLM lands. Ability to conduct efficient cross-ownership area-wide invasive plant control projects. Very difficult, as most adjacent landowners use herbicides for much of their invasive plant control. Difficulty in conducting cross-ownership projects contributes to reduced (60%) control efficiency. Some cooperators choose to use BLM’s four herbicides 

for simplicity.

Cooperative control efforts could take place on BLM lands because most of the herbicides already being used by these groups on adjacent lands would be available. Effective control covering entire geographically logical areas would be available for more weed species. Adjacent landowners will be more effective at controlling species of weeds that BLM has been unable to treat under the No Action Alternative (conceivably reducing total use). State and private control dollars may go farther if treatments are more uniformly applied and thus more effective. Better meets State laws requiring noxious weed control.

Noxious weed control benefit from roadside native plant control.

Non-herbicide mowing and scraping less likely to incidentally remove undetected noxious weeds than herbicides; cause ground disturbance then subject to invasion; and mowing equipment or graders have the potential to move noxious weeds.

Native plant control along roads by permit/right-of-way holders like Oregon Department of Transportation would further reduce noxious weed spread.

6. Prevent herbicide control treatments from having unacceptable adverse effects to applicators and the public, to desirable flora and fauna, and to soil, air, and water.Total herbicide acres1 0 22,800 32,900 48,200 54,100

Total herbicide lbs (typical rate) 0 23,010 14,830 34,695 38,275Average herbicide lbs/acre 0 1.01 0.45 0.72 0.71

Acres of high and moderate-risk herbicides by resource:3

Risk categories are based on modeled scenarios. Standard Operating Procedures and PEIS Mitigation Measures are designed to minimize these risks.

Terrestrial/aquatic plants 0 Herbicides are designed to kill plants. Almost all have a high or moderate risk of killing non-target plants if they are sprayed.Fish 0 14,4002 7,0002 12,0002 14,4002Mammals, Wild Horses 0 22,800 11,600 21,000 24,600Birds 0 19,000 9,900 16,500 19,200Aquatic Invertebrates 0 4,600 1,300 4,500 5,400Insects 0 5,900 4,900 9,800 11,000

Table 2-6. 

R

esponse

of the

A

lternatives t

o

the

Pur

poses (continued)
49

Final Environmental Impact Statement, Chapter 2: The Alternatives

Purpose/Parameter Reference Analysis Alt. 2 (No Action) Alt. 3 Alt. 4 (Proposed Action) Alt. 5

Average 0 13,340 6,940 12,760 14,920% of No Action Alt. 0% 100% 52% 96% 112%Average % of total herbicide acres that are treated with high or moderate-risk herbicides. 

N/A 59% 21% 26% 28%

Cumulative Impacts Widely dispersed use, less than 1% of State’s herbicide use on 25% of the acres, reduces likelihood of cumulative effects.Acres of high and moderate risk for human health:4 Risk categories are based on modeled scenarios. Standard Operating Procedures and PEIS Mitigation Measures are designed minimize these risks.

Workers and public 0 8,500 4,000 8,000 10,800

% of No Action Alt. 0% 100% 47% 94% 127%% of total herbicide acres that are treated with high or moderate-risk herbicides.

N/A 37% 12% 17% 20%

7. Control plant pests and diseases by removing their native plant hosts when necessary to meet Oregon Department of Agriculture-identified control objectives.Native Host Control 38% reinfection of tanoak sprouts, infestation continues to spread slowly. 6% reinfection of tanoak sprouts, could lead to containment of the infestation.8. Minimize treatment costs and improve treatment effectiveness, so economic losses from invasive plants and other vegetation growth are reduced and more of the Needcan be met within expected funding. Percent of invasive plant treatments expected to result in final control

30% 60% 80% 80% 80%

Effectively treated invasive plant acres5 12,630 27,300 46,160

46,160

(plus 2,350 acre benefit 

from native plant right-ofway treatments)

46,160

(plus 2,350 acre benefit 

from native plant right-ofway treatments)

Cost per effectively treated acre

$565 $240 $193 $193 $193

1 This is the total of the acres treated with each herbicide. It is larger than the gross treatment acres in Table 3-3 because acres treated with tank mixes are double or triple counted, once for each herbicide applied.2 Worst case. Numbers assume terrestrial glyphosate (with POEA). Aquatic-labeled glyphosate is used near water, and used in many other areas.3 Not including accidental & spill exposures. Includes maximum application rates even if PEIS Mitigation Measures recommends against it.4 Typical rate; includes all exposure scenarios.5 Effectively treated acres are the portion of the annual program not expected to need retreatment because final control objectives have been achieved.

Table 2-6. 

R

esponse

of the

A

lternatives t

o

the

Pur

poses (continued)
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 50

The Preferred Alternative

Alternative 4, the Proposed Action, is the Preferred Alternative. It meets the Need and best meets all eight 

Purposes. Like Alternative 3, the additional, generally newer, herbicides are more target-specific, can be used in 

lower doses, and are generally less likely to adversely affect non-target plants and animals than the four herbicides 

currently in use. The additional herbicides would also be effective against a wider array of invasive plants, 

including the invasive annual grasses medusahead and cheatgrass, as well as other weeds for which there are 

currently no effective controls available to the BLM in Oregon. 

The ability to treat native and other non-invasive vegetation encroaching on rights-of-ways, recreation sites, and 

administrative sites with herbicides under Alternative 4 would reduce the cost for these regular maintenance 

treatments by about $1 million per year, would reduce ground disturbance that can encourage invasive plants, 

and would control small undetected populations just getting established along roads and other public use areas. 

Alternative 4 would also allow the use of herbicides for improving habitat for Federally Listed and other Special 

Status species like sage grouse. 

Alternative 5 would have the same benefits as Alternative 4, and it would make herbicides available for the full 

range of resource management activities except livestock forage and timber production. Alternative 5 is estimated 

to increase herbicide use by ten percent from Alternative 4, and most of this increase would be expected to go 

toward additional habitat improvement projects not practical without herbicides. However, there is a lower need 

for herbicides for these activities, and the alternative departs from the narrow program clarity and focus requested 

by many of the scoping comments. 

Potential Mitigation

Introduction

Mitigation measures avoid, minimize, rectify, reduce, or compensate for adverse environmental impacts of 

management actions (40 CFR 1508.20). NEPA implementing regulations require agencies to “...include 

appropriate mitigation measures not already included in the proposed action or alternatives” and include a 

discussion of “means to mitigate adverse environmental impacts” (40 CFR 1502.14(f) and 1502.16(h)). The 

regulations also require that in the Record of Decision, the responsible officials “state whether all practicable 

means to avoid or minimize environmental harm from the alternative selected have been adopted, and if not, 

why they were not” (40 CFR 1505.2). Consistent with those requirements, mitigation measures are identified 

and described here for all potential adverse effects identified for the Proposed Action (Alternative 4). Mitigation 

measures do not include “don’t do” or “select another alternative,” as these choices are addressed by other 

alternatives and/or may not meet the Need and Purposes for the Proposed Action.

The following potential mitigation measures were identified to respond to adverse effects identified in this EIS. If 

a resource section in Chapter 4 is not shown below, it means the potential for adverse effects to that resource were 

deemed negligible, or no practicable mitigation measures were identified that would mitigate the effects identified. 

The mitigation measures listed below are in addition to mitigation measures identified in the PEIS, adopted by the 

Record of Decision for the PEIS, and listed in Appendix 2 and considered a part of all of the alternatives. In an 

attempt to avoid confusion, those mitigation measures are referred to herein as PEIS Mitigation Measures. 
Final Environmental Impact Statement, Chapter 2: The Alternatives

51

The decision-maker’s decision to reject, modify, or apply each of the following mitigation measures to the 

selected alternative will be described in the Record of Decision. The decision-maker may decline to select 

identified mitigation measures because the adverse effect it is supposed to address is acceptable in light of the 

potential for increased cost or decreased effectiveness of the selected alternative, and/or because the decisionmaker believes other measures will adequately address the concern. 

Potential Monitoring, Appendix 3

Part II of the Monitoring Appendix (Appendix 3), presents potential monitoring measures designed to track 

implementation and effectiveness of the program changes that might result from the selection of one of the action 

alternatives. Although no reduction in adverse effects can be attributed to monitoring per se, the proposals in that 

section should be selected or rejected in the Record of Decision at the same time as the potential mitigation measures.

Potential Mitigation12

Soil Resources

• To avoid the loss of finer-sized soil particles and avoid having herbicide-treated soils blown or washed 

off-site, avoid exposing large areas of wind-erosion group 1 or 2 soils (see Figure 4-5) during the windy 

season. Mitigation measures could include the use of selective herbicides to retain some vegetation on 

site; reseeding so cover is present before the windy season affects dry soils; staggering treatment of strips 

until stubble regrows enough to provide an acceptable filter strip; rescheduling treatments away from the 

windy season; or, other measures to prevent wind erosion on these soil groups. 

Water Resources

• To protect domestic water sources, no herbicide treatments should occur within 100 feet of a well or 200 

feet of a spring or known diversion used as a domestic water source, unless a written waiver is granted by 

the user or owner.

• Where diquat applications would be used on vast enough areas that de-oxygenation from plant 

decomposition would cause unacceptable effects to aquatic fauna, either 1) remove treated vegetation or 

2) the area would be treated in swaths over several months time to minimize de-oxygenation of the water 

due to plant decomposition.

• Site-specific analyses for roadside treatments should specifically consider that drainage structures lead to 

streams, and that normal buffer distances, herbicide selection, and treatment method selection may need to 

be changed accordingly, particularly where those ditches are connected to streams with Federally Listed or 

other Special Status species.

• Buffer intermittent stream channels when there is a prediction of rain (including thunderstorms) within 

48 hours.

• Proposals to boom or aerially spray herbicides within 200 feet of streams that are within 1,000 feet 

upstream from a public water supply intake, or spot apply herbicides within 100 feet of streams that are 

within 500 feet upstream from a public water supply intake, will include coordination with the ODEQ and 

the municipality to whom the intake belongs.

12 Potential mitigation was not identified for some resources because Standard Operating Procedures and PEIS Mitigation 

Measures were adequate, no adverse effects were identified, or no additional mitigation was available.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 52

Fish

• Use of adjuvants with limited toxicity and low volumes is recommended for applications near aquatic 

habitats. 

Wildlife Resources

• Impacts to wildlife from herbicide applications can be reduced by treating habitat during times when 

the animals are not present or are not breeding, migrating or confined to localized areas (such as crucial 

winter range). 

• Herptile (amphibian and reptile) and mollusk mortality due to vegetation management can be 

minimized by conducting activities during the winter hibernation or estivation period. If management 

is to occur in occupied habitat during the active season, the following approaches should be considered 

to minimize impacts:

◦ Avoid control work when herptiles and mollusks are most active;

◦ Leave some habitat untreated to provide refugia: untreated portions could be treated in subsequent 

seasons; and, 

◦ Avoid treatments that would curtail herptile spring and fall migrations to and from breeding or 

wintering habitats.

• When treating native plants in areas where herbivores are likely to congregate, choose herbicides with 

lower risks due to ingestion.

• Where there is a potential for herbivore consumption of treated vegetation, apply bromacil, dicamba, 

imazapyr, and metsulfuron methyl at the typical, rather than maximum, application rate to minimize risks. 

• Where possible, design native vegetation treatment areas to mimic natural disturbance mosaics. 

Patchiness is usually beneficial to most wildlife, and patchiness is usually tolerated by species that prefer 

contiguous habitat. 

• Use of adjuvants with limited toxicity and low volumes is recommended for applications near aquatic habitats. 

Livestock

• Where there is a potential for livestock consumption of treated vegetation, apply bromacil, dicamba, 

imazapyr, metsulfuron methyl, and tebuthiuron at the typical, rather than maximum, application rate to 

minimize risks to livestock.

Wild Horses and Burros

• Where there is a potential for wild horse or burro consumption of treated vegetation, apply bromacil, 

dicamba, imazapyr, and metsulfuron methyl at the typical, rather than maximum, application rate to 

minimize risks. 

• Do not broadcast spray 2,4-D, clopyralid, diflufenzopyr + dicamba, diuron, glyphosate, hexazinone, 

picloram, or triclopyr where wild horses have unrestricted access to treated areas, or reduce risks to wild 

horses from these herbicides by herding wild horses out of treatment areas.

• To limit adverse effects to wild horses and burros, particularly through the contamination of food items, 

treatments should not exceed 15 percent of any Herd Management Area at any given time. 
Final Environmental Impact Statement, Chapter 2: The Alternatives

53

Social and Economic Values

• For herbicides with label-specified re-entry intervals, post information at access points to recreation 

sites or other designated public use or product collection areas notifying the public of planned herbicide 

treatments in languages known to be used by persons likely to be using the area to be treated. Posting 

should include the date(s) of treatment, the herbicide to be used, the date or time the posting expires, and a 

name and phone number of who to call for more information. 

• Consider the potential for treatments to affect communities from herbicide-contaminated resources 

originating from BLM, such as subsistence resources or water used downstream for human or agricultural 

uses.

• Coordinate with and/or notify neighboring landowners who may want to treat, or are already treating, 

adjacent lands.

Environmental Justice

• To the extent permitted by normal contracting authority, ensure materials safety data sheets and 

other informational or precautionary materials are available in languages spoken by the work crews 

implementing treatments. This includes but is not limited to material such as Occupational Safety and 

Health Administration standards along with agency, industry and manufacturers’ recommendations and 

Human Health and Safety Standard Operating Procedures and mitigation measures or equivalent.

Human Health and Safety

• Consideration should be given to herbicides other than 2,4-D; use of 2,4-D should be limited to situations 

where other herbicides are ineffective or in situations in which the risks posed by 2,4-D can be mitigated.

• Do not apply triclopyr by any broadcast method.

• Do not apply bromacil, diuron, or tebuthiuron when there is a potential for picking sprayed fruit. Do not 

broadcast spray onto vegetation more than a foot tall when and where public contact is likely, such as on 

tall grass or low brush around developed sites and other high use areas.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 54
55

Chapter 3

Changes Between Draft and Final EIS

The following changes were made to Chapter 3 between the Draft and Final EIS. Minor corrections, 

explanations, and edits are not included in this list.

Changes were made to:

• Clarify the existing Integrated Vegetation Management and Resource Management Plan context for the 

proposed increase in the number of herbicides available for use;

• Add more information about the specific uses of each of the 18 herbicides;

• Add additional information about adjuvants and inerts;

• Clarify why there are different herbicides proposed for east and west of the Cascades;

• Add additional information about how vegetation treatment methods are selected;

• Add information about drift as a potential herbicide exposure pathway;

• Add additional descriptive material about the high, moderate, and low categories used on the risk tables;

• Add toxicity information about some common household materials to help set the context for risk and 

exposure;

• Add information about specific herbicides so the reader could better understand the objectives of having 

specific herbicides available;

• Update ecological and human health risks for triclopyr, hexazinone, and 2,4-D based on Risk Assessments 

developed since the PEIS was written; and,

• Correct certain ecological and human health risks for dicamba to reflect findings of the Forest Service Risk 

Assessment. The risk ratings in the Draft EIS were based on a BLM Risk Assessment that considered 

dicamba in combination with diflufenzopyr.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 56

Table of Contents

Chapter 3 - Background and Assumptions for Effects Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Background for Effects Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

The 18 Herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Assumptions and Information about Treatment Acres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Integrated Vegetation Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Herbicide Treatment Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Non-Herbicide Treatment Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Treatment Acres, Gross Acres and Net Acres, and Pounds of Herbicides to be Applied . . . . . . . . . . . . . . . . . . . . . . . . 77

Assumptions about Herbicide Treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

EPA Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Risk Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Drift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

High, Moderate, and Low Risk in BLM and Forest Service Risk Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Uncertainty in the Risk Assessment Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Use of the Individual Risk Assessment Tools During Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Toxicity Comparison with Household Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Methodology for Assessing Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Standard Operating Procedures, PEIS Mitigation Measures, Risk, and the Potential 

for Adverse Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Tables

Table 3-1. Herbicide Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 3-1. Herbicide Information (continued) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Table 3-1. Herbicide Information (continued) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Table 3-3. Estimated1 Annual Treatment Acres West/East7 of the Cascades for Each Alternative. . . . . . . . . . . . . . . . . . . . . . . . . . 77

Table 3-4. Estimated Annual Pounds of Herbicides that Would be Applied at Typical and Maximum

 application Rates East/West of the Cascades for Each Alternative. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Table 3-5. 2006-2008 Oregon BLM Pesticide Use Reports Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Table 3-6. Ground and Aerial Herbicide Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Table 3-7. Estimated Annual Herbicide Treatment Acres under Alternatives 3, 41, and 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Table 3-8. Estimated Change in Native Vegetation Annual Treatment Acres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Table 3-9. Herbicide Label Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Table 3-10. Human Health and Ecological Risk Assessment Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Table 3-11. Comparison of oral LD50 values1 for commonly used herbicides and consumer goods. . . . . . . . . . . . . . . . . . . . . . . . . 92

Table 3-12. BLM-Evaluated Herbicide Risk Categories for Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Table 3-13. FS-Evaluated Herbicide Risk Categories for Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Table 3-14. BLM-Evaluated Herbicide Risk Categories for Wildlife, Fish, and Aquatic Species . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Table 3-15. FS-Evaluated Herbicide Risk Categories for Wildlife, Fish, and Aquatic Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table 3-16. BLM-Evaluated Herbicide Risk Categories for Workers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Table 3-17. BLM-Evaluated Herbicide Risk Categories for the Public . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Table 3-18. FS-Evaluated Herbicide Risk Categories for Workers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Table 3-19. FS-Evaluated Herbicide Risk Categories for the Public . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Table 3-20. BLM 1991-Evaluated Herbicide High Risk Scenarios for Workers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Table 3-21. BLM 1991-Evaluated Herbicide High Risk Scenarios for the Public . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Figures

Figure 3-1. Basis for Risk Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
57

Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

Chapter 3 

Background and Assumptions for 

Effects Analysis

Introduction

This EIS tiers to the 2007 National Vegetation Treatments Using Herbicides on Bureau of Land Management 

Lands in 17 Western States Programmatic Environmental Impact Statement (PEIS), which is incorporated into this 

EIS as uncirculated Appendix 1. This appendix is available online at the web addresses listed on the Appendix 

1 cover page in the appendices of this EIS, or may be obtained on compact disk or printed copy by contacting 

the BLM via phone, email, or mail (see title page). An attempt is made to summarize and include all parts of the 

PEIS analysis pertinent to an examination of the potential significant environmental effects of the alternatives. 

However, additional details about methodology, background material, and references remain in the PEIS, and 

readers seeking additional information are encouraged to refer to the corresponding sections in the PEIS. In each 

case, the decision about the detail to bring forward or otherwise include in this EIS was based primarily on its 

applicability to the Purposes presented in Chapter 1.

The three action alternatives presented in this EIS fit completely within PEIS Alternative B (the alternative 

selected in the Record of Decision for the PEIS) in that they present the same or fewer herbicides than considered 

in Alternative B, apply them to all or fewer acres than were assumed in Alternative B, and consider those 

herbicides for fewer of the treatment objectives included in Alternative B. All Standard Operating Procedures 

included in Alternative B, as well as all PEIS Mitigation Measures, apply to these alternatives. Therefore, the 

potential for adverse human health or environmental effects resulting from actual application of herbicides 

should, at the programmatic scale, fall generally within those described in the PEIS for Alternative B. Apparent 

differences from PEIS-identified effects are generally attributable to: 1) examination of Oregon-specific 

conditions at a finer scale than in the PEIS, and 2) lower levels of vegetation control than assumed in the PEIS. 

Background for Effects Analysis

This EIS addresses large, regional-scale trends and issues that require integrated management across broad 

landscapes. It also addresses regional-scale trends and changes in the social and economic needs of people. 

This analysis does not identify site-specific effects because projects have not been identified and because sitespecific information is not essential for determining the effects of broad-scale management direction. As noted 

in Chapters 1 and 2, site-specific issues would be addressed through NEPA analysis at the district or project level. 

This EIS does not analyze specific projects.

The action alternatives in this EIS would only make additional herbicides available to vegetation management 

programs already described in Resource Management Plans and other local plans. The EIS does not propose 

new activities, nor does it propose to constrain existing activities. Because vegetation management is already 

being done in support of Plan objectives, and because herbicides are already being used as one method of treating 

noxious weeds, a complete examination of whether or not to conduct vegetation management or whether to 
 58

Vegetation Treatments Using Herbicides on BLM Lands in Oregon

conduct activities with some other method, would be moot. Alternative methods are already being used to the 

extent practicable. This Chapter attempts to describe how the additional herbicides would be applied, using the 

existing vegetation management priorities and process (Integrated Vegetation Management) as the context. Nonherbicide methods are addressed only to the extent their conduct would change as a result of the herbicide use that 

would occur under each of the alternatives. Non-herbicide methods are otherwise addressed in existing RMPs, 

and in the Final Vegetation Treatments on BLM Lands in 17 Western States Programmatic Environmental Report.

The 18 Herbicides

The 18 herbicides proposed for use in this EIS are a subset of the hundreds of herbicides registered for use 

in the U.S. They were chosen by the BLM nationally for maximum effectiveness against wildland weeds 

and least environmental and non-target species’ risks. Table 3-1 shows information about each herbicide that 

affects how it would be used. Additional information about the herbicides and the plants they control is in 

Appendix 9 and listed below.

Herbicides can be categorized as selective or non-selective (see Table 3-1). Selective herbicides kill only a 

specific type of plant. For example, an herbicide selective for broadleaved plants can be used to manage such 

species while maintaining desirable grass species in rangeland communities. Non-selective herbicides kill all 

types of plants, and thus must be applied only to the target species. Herbicides can be used selectively to control 

specific types of vegetation (e.g., killing invasive weeds), or non-selectively to clear all vegetation on a particular 

area (e.g., keeping a roadway clear of vegetation). 

Some herbicides are post-emergent, which means they can be used to kill existing vegetation; others are preemergent, which stops vegetation before it grows (e.g., prohibiting seeds from germinating) (Table 3-1). 

Resource-specific discussions of the uses and risks associated with each herbicide are included in each of the 

resource sections in Chapter 4.

Formulations (brands) and adjuvants are limited to those on the BLM National list of approved herbicides and 

adjuvants, which is reviewed and updated at least annually (see Appendix 9 for the 2010 version). This list 

identified herbicides that are known to be consistent with the formulations analyzed in the Risk Assessments and 

otherwise suitable for wildland use.
59

Table 3-1. 

Herbicide Information

Herbicide

Representative Trade Names1 Common Targets

Selective 

to Plant 

Types

Pre/post 

Emergent 

Point of 

Application

Types of BLM 

Lands Where Use is 

Permitted

Application Rate

(lbs/acre/year) Available under Alternative4

Aerial 

Spray5

Allowed

K

oc

6

Solubility7 

(mg/l)

SPISP II Rating8 (Leaching 

Potential)

Rangeland

Forest Land

Riparian or Aquatic

Oils, Gas, & Mineral Sites

Rights-of-Way

Recreation & Cultural Sites Typical Max2 Alt. 2 - No Action Alt. 

3

Alt. 4 - 

Proposed 

Action Alt. 5

PLP9

Leaching

PSRP10

Solution 

Runoff

PARP11

Adsorbed 

Particle 

Runoff

2, 4-D

Many, including Amine, Hardball, Unison, Saber, Salvo, AquaKleen, and Platoon

Annual and biennial broadleaf weeds. Kochia, whitetop, perennial pepperweed, Russian thistle and knapweed, sagebrush, rabbitbrush.

broadleaf

Post Foliar

√ √ √ √ √ √ 1 (1.9) √ √ √ √ Yes 20-100 33,900 Inter- mediate Inter- mediate Low

Bromacil 

Hyvar

Annual grasses and broadleaf weeds. Cheatgrass, puncturevine, ragweed, wild oat, dandelion, quackgrass, wild carrot. 

no

Pre and post Soil

√ √ √ 4 (12) E √ No 32 700 High High Inter- mediate

Chlorsulfuron3

Telar

Thistles, wild carrot, giant horsetail, poison hemlock, Russian knapweed, marestail, perennial pepperweed, puncturevine, tansy ragwort, common tansy, common teasel, dalmation toadflax, yellow toadflax, whitetop, dyers woad

broadleaf

Pre and early postSoil or foliar

√ √ √ √ 0.047 0.141 E E √ Restricted13 40 7,000 High High Inter- mediate

Clopyralid 3, 12

Transline, Stinger, Spur

Thistles, common burdock, knapweeds, yellow starthistle, oxeye daisy, hawkweeds, prickly lettuce, dandelion, cutleaf teasel, kudzu, buffalobur

broadleaf

PostFoliar

√ √ √ √ √ 0.35 0.5 √ √ √ Yes 2 1,000 High Inter- mediate Low

Dicamba 

Vanquish, Banvel, Diablo, Vision, Clarity

Knapweeds, kochia, and thistles.

broadleaf, woody plants

Pre and post Foliar

√ √ √ √ 0.3 2 √ √ √ √ Yes 2 400,000 High Inter- mediate Low

Diflufenzopyr + Dicamba 

Overdrive, Distinct

Knapweeds, kochia, and thistles.

broadleaf

PostFoliar

√ √ √ √

0.2625 0.4375 √ No

Diflufenzopyr No 87 5,850 Low Inter- mediate LowDiquat 

Reward

Giant salvinia, hydrilla, and watermilfoils. no

PostAquatic

√ 1 (4) √ Restricted14 1,000,000 718,000 Very Low Low High

Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis
 60

Herbicide

Representative Trade Names1 Common Targets

Selective 

to Plant 

Types

Pre/post 

Emergent 

Point of 

Application

Types of BLM 

Lands Where Use is 

Permitted

Application Rate

(lbs/acre/year) Available under Alternative4

Aerial 

Spray5

Allowed

K

oc

6

Solubility7 

(mg/l)

SPISP II Rating8 (Leaching 

Potential)

Rangeland

Forest Land

Riparian or Aquatic

Oils, Gas, & Mineral Sites

Rights-of-Way

Recreation & Cultural Sites Typical Max2 Alt. 2 - No Action Alt. 

3

Alt. 4 - 

Proposed 

Action Alt. 5

PLP9

Leaching

PSRP10

Solution 

Runoff

PARP11

Adsorbed 

Particle 

Runoff

Diuron 

Direx, Karmex

Annual grasses (including bluegrass) and broadleaf weeds. Lambsquarters, kochia and Russian thistle.

annual weeds, some perennials

PreSoil

√ √ √ 6 (20) √ √ No 480 42 Inter- mediate High Inter- mediate

Fluridone 

Avast!, Sonar Hydrilla and watermilfoils submersed plants Post Aquatic

√ 0.15 (1.3) √ √ √ Yes 1,000 10 Low Inter- mediate Inter- mediate

Glyphosate3

Many, including Rodeo, Mirage, Roundup Pro, and Honcho

Grasses (including Italian ryegrass), sedges, broadleaf weeds, and woody shrubs.

no

PostSoil or foliar

√ √ √ √ √ √ 2 7 √ √ √ √ Yes 24,000 900,000 Very Low High High

Hexazinone 

Velpar

Annual and perennial grasses and broadleaf weeds, brush, and trees.

grasses, broadleaf, woody plants 

Pre and postSoil or foliar

√ √ √ √ √ 2 (4) √ √ √ Yes 54 33,000 High High Inter- mediate

Imazapic3

Plateau, Panoramic

Cheatgrass, leafy spurge, medusahead, whitetop, dalmation toadflax and Russian knapweed.

some broadleaf and grasses

Pre and postSoil

√ √ √ √ √ 0.0313 0.1875 √ √ √ Yes 137 2,200 High High Inter- mediate

Imazapyr3

Arsenal, Stalker, Habitat, Polaris

Annual and perennial broadleaf weeds, brush, trees.Saltcedar, Russian olive, tanoak

no

Pre and postSoil or foliar

√ √ √ √ √ √ 0.45 1.25 √ √ √ Yes 100 >11,000 High High Inter- mediate

Metsulfuron methyl3

Escort, Patriot, PureStand

Whitetop, perennial pepperweed and other mustards and biennial thistles.

broadleaf, woody plants

PostSoil or foliar

√ √ √ √ √ 0.03 0.15 √ √ √ Restricted13 35 9,500 High High Inter- mediate

Picloram3

Triumph, OutPost, Tordon

Perennial and woody species. Knapweeds, starthistle, thistle, bindweed, leafy spurge, rabbitbrush, rush skeletonweed, and poison oak.

broadleaf, woody plants

Pre and postFoliar

√ √ √ √ √ 0.35 1 √ √ √ √ Yes 16 200,000 High High Inter- mediate

Sulfometuron methyl3

Oust, Spyder

Cheatgrass, annual and perennial mustards, and medusahead.

no

Pre and postSoil or foliar

√ √ √ √ 0.14 0.38 √ √ √ No 78 70 Inter- mediate High Low

Vegetation Treatments Using Herbicides on BLM Lands in Oregon

Table 3-1. 

Herbicide Information (continued)
61

Herbicide

Representative Trade Names1 Common Targets

Selective 

to Plant 

Types

Pre/post 

Emergent 

Point of 

Application

Types of BLM 

Lands Where Use is 

Permitted

Application Rate

(lbs/acre/year) Available under Alternative4

Aerial 

Spray5

Allowed

K

oc

6

Solubility7 

(mg/l)

SPISP II Rating8 (Leaching 

Potential)

Rangeland

Forest Land

Riparian or Aquatic

Oils, Gas, & Mineral Sites

Rights-of-Way

Recreation & Cultural Sites Typical Max2 Alt. 2 - No Action Alt. 

3

Alt. 4 - 

Proposed 

Action Alt. 5

PLP9

Leaching

PSRP10

Solution 

Runoff

PARP11

Adsorbed 

Particle 

Runoff

Tebuthiuron 

Spike Sagebrush (thinning)

broadleaf, woody plants

Pre and postSoil

√ √ √ √ 0.5 (4) E √ Restricted15 80 2,500 High High Inter- mediate

Triclopyr3

Garlon, Renovate, Element

Saltcedar, purple loosestrife, Canada thistle, tanoak, Himalayan blackberry

broadleaf, woody plants 

PostFoliar

√ √ √ √ √ √ 1 (10) √ √ √ Yes 20 (salt) 780 (ester) 435 High High Inter- mediate

1 See Appendix 9 (Additional Information About the 18 Herbicides) for the full list of herbicide trade names allowed for use on BLM Lands in Oregon, including formulations with 2 or more active ingredients.2 Parentheticals denote herbicides that are limited, by PEIS Mitigation Measures, to typical application rates, where feasible.3 These, and sethoxydim, are approved for use by the Forest Service in Oregon and Washington (USDA 2005b).4 √ indicates herbicides that would be available statewide; E indicates herbicides that would be available only to districts east of the Cascades5 Aerial spraying not allowed for any districts west of the Cascades under Alternatives 3 and 4.6 K

oc: Soil organic carbon sorption coefficient of an active ingredient in mg/L. For a given chemical, the greater the Koc value, the less soluble the chemical is in water and the higher affinity the chemical has for soil 

organic carbon. For most chemicals, a higher affinity for soil organic carbon (greater Koc) results in less mobility in soil7 Solubility indirectly relates to runoff potential, if solubility number is low runoff potential is high8 SPISP II = Soil Pesticide Interaction Screening Procedure version II, which is a NRCS model that calculates leaching potential from basic soil properties (USDA 1994b).9 PLP - Pesticide Leaching Potential indicates the tendency of a pesticide to move in solution with water and leach below the root zone. A low rating indicates minimal movement and no need for mitigation. PLP is calculated according to a WIN-PST algorithm, and then the resulting rating is adjusted for type of spraying being conducted.10 PSRP - Pesticide Solution Runoff Potential indicates the tendency of a pesticide to move in surface runoff in the solution phase. A rating as calculated according to a WIN-PST algorithm indicates the potential for pesticide loss in solution runoff. Ratings are adjusted according to type of spraying being conducted.11 PARP - Pesticide Adsorbed Runoff Potential indicates the tendency of a pesticide to move in surface runoff attached to soil particles. A rating as calculated according to a WIN-PST algorithm indicates potential for pesticide movement adsorbed to sediment. Ratings are adjusted according to type of spraying being conducted.Data source: USDA 2006a12 The State of Oregon limits the use of clopyralid. OAR 603-057-0378 states, “

Any application or use of a pesticide product known to contain the active ingredient clopyralid to a location other than an agricultural 

site, forest site, right-of way site, golf course site, or non-turf area of a park or recreation site is prohibited. Regardless of application or use sites specified on individual product labels, no application or use may be made to lawn or turf areas such as residential lawns, commercial and public turf plantings, school grounds, parks, cemeteries or recreational areas other than golf courses.”13 Only allowed when no other means of application are possible.14 Not allowed in wetland or riparian areas (allowed in aquatic areas).15 Not allowed in traditional use areas; not allowed in areas where tebuthiuron drift could reach aquatic Special Status species (further than ~100 ft from riparian areas).

Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

Table 3-1. 

Herbicide Information (continued)
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Herbicide Uses

To supplement the herbicide information presented on Table 3-1, Appendix 9, and elsewhere, the following 

information about the specific uses of each herbicide is provided to help the reader understand how each would 

contribute to achieving the different management objectives identified in each of the action alternatives. 

2,4-D (available under all alternatives) is effective on a wide range of broadleaf weeds while protecting most 

grasses. While having additional herbicides available can allow for more target specific control, having one 

herbicide that controls a vast range of vegetation could reduce operator error that can occur while mixing and 

applying herbicides. The Oregon BLM has used 2,4-D without incident to human health for 23 years. In 

addition, adding a small amount of 2,4-D to a tank mix can improve the effectiveness of the other herbicides and 

reduce resistance. Additional information about 2,4-D can be found in Appendix 12. 2,4-D is available under the 

No Action Alternative (Alternative 2); use of 2,4-D drops statewide under all of the action alternatives.

The primary use for diuron (available under Alternatives 4 and 5) would be in communications sites such as cell 

phone, radio, television tower sites, electrical substations, or similar facilities where no vegetation is desired. A 

bare ground herbicide would permit treatments of these sites every 2-3 years (see the Administrative Sites, Roads, 

and Rights-of-Way section in Chapter 4). It also has use as a site-preparation tool for nursery beds. Bromacil 

(available under Alternatives 4 and 5), like diuron, is a non-selective herbicide that kills all vegetation. The 

primary use for bromacil would be in communications sites such as cell phone, radio, television tower sites, 

electrical substations, or similar facilities where complete vegetation control is desired to reduce fire risk and 

maintenance costs. 

Fluridone (available under Alternatives 3, 4, and 5) is an aquatic herbicide that requires prolonged plant contact, 

so it can only be used on aquatic plants in still water. It would be used primarily on Brazilian waterweed, elodea, 

hydrilla, and watermilfoil.

Diquat is an aquatic herbicide that is included only in Alternative 5. Of the 18 herbicides analyzed in the PEIS, 

this is the only herbicide that can control giant salvinia, which has not been found in Oregon.

Hexazinone (available under Alternatives 3, 4, and 5) would be primarily used in administrative sites, utility 

and road rights-of-way, and along the deer exclosure fence lines at the seed orchards where vegetation must be 

removed to facilitate maintenance. It could also be used on African rue, a bushy invasive perennial that is toxic to 

people and livestock.

Glyphosate (available under all alternatives) is being used on broadleaf weeds and woody species and has been 

used to treat medusahead in eastern Oregon. However, it is a non-selective herbicide and can harm desirable 

plants, so use has been limited to areas where this is an acceptable treatment. Glyphosate could be used on 

administrative sites, rights-of-way, and recreation sites under the Proposed Action (Alternative 4). Glyphosate 

and 2,4-D have been the only two aquatic herbicides available to the BLM for the past 23 years, and use would 

decrease as more aquatic herbicides became available. 

Imazapyr (available under Alternatives 3, 4, and 5) is an ALS-inhibitor that is effective against brushy and woody 

species such as saltcedar and Russian olive. It would also be used on tanoak to control sudden oak death. At high 

doses, it is an effective bare ground herbicide that could be used in areas other bare ground herbicides are not 

registered for. It is used to treat African rue, Japanese knotweed, and leafy spurge.

Tebuthiuron (available under Alternatives 4 and 5) would primarily be used at low rates to thin sagebrush to 

improve habitat for sage grouse and other species. It could also be used at high rates as a bare ground herbicide.
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

63

Imazapic (available under Alternatives 3, 4, and 5), an ALS-inhibitor, is especially effective against the invasive 

annual grasses such as cheatgrass and medusahead, which infest more than 5 million acres in eastern Oregon. At 

low rates, it is selective for these grasses, leaving the perennial herbaceous species critical for restoration. The 

BLM does not currently have an effective method of treating these fire-prone invasive annual grasses. Like 

imazapic, sulfometuron methyl (available under Alternatives 3, 4, and 5) an ALS-inhibitor, is effective against 

cheatgrass and medusahead. It has a shorter half-life than imazapic, which speeds restoration efforts. However, 

sulfometuron methyl is not applied aerially, and is not registered for use in rangeland, and a current EPA proposal 

would limit its use in drier areas (see Chapter 1). This would limit its use on grasses to invasive grasses occurring 

in woodlands and forest openings. In addition, sulfometuron methyl is effective on mustards and can harm 

desirable forb species. In high doses, it would be used on road rights-of-way as a bare ground herbicide.

Dicamba (available under all alternatives) has been used extensively on thistles and perennial pepperweed; in 

combination with 2,4-D on mustards and knapweeds; and, in combination with picloram for rush skeletonweed. 

Use would drop under the action alternatives, and chlorsulfuron and metsulfuron methyl would be used for 

many of these treatments. However, dicamba provides good burn-down right up to seed set, which extends the 

treatment window. Diflufenzopyr + Dicamba is included only in Alternative 5. It would be used for many of 

the same species as dicamba. It can be used in a mixture with picloram, triclopyr, and clopyralid, allowing for a 

reduced rate of these chemicals.

Chlorsulfuron (available under Alternatives 3, 4, and 5) is an ALS-inhibitor that is effective against grasses and 

broadleaf plants such as whitetop, perennial pepperweed, Mediterranean sage, and thistles. It is often mixed with 

2,4-D to reduce the likelihood of developing plant resistance and to produce more immediately visible results. It 

can also be used on toadflax and knapweeds. Metsulfuron methyl (available under Alternatives 3, 4, and 5) has 

similar targets and effects as chlorsulfuron, but can cause more harm to desired meadow grasses. It could be used 

on perennial pepperweed, whitetop and other mustards, and blackberries. It can also be used to control conifer 

trees under power lines.

Picloram (available under all alternatives) has been used on rush skeletonweed, knapweeds, toadflax, and thistles, 

and provides good residual control. Use would decrease under any of the action alternatives, and clopyralid, 

which is more selective, would likely be used instead. However, it is also effective on western juniper and could 

be used to improve sage grouse habitat. Clopyralid (available under Alternatives 3, 4, and 5) would target many 

of the same species as picloram, but is more selective. It is effective on knapweeds and Canada thistle, while 

minimizing risk to surrounding desirable brush, grass, and trees.

Triclopyr (available under Alternatives 3, 4, and 5) is effective on woody plants, and would be used on saltcedar, 

Russian olive, blackberries, brooms, and other shrubs. It is the preferred treatment for purple loosestrife, and 

could be used to control woody species in recreation sites. Triclopyr BEE, the ester formulation, is more effective 

at smaller doses, but is more toxic to fish.

Adjuvants, Impurities, and Other Ingredients

Adjuvants are compounds added to the formulation to improve its performance. They can enhance the activity 

of an herbicide’s active ingredient (activator adjuvant) or offset any problems associated with its application 

(special purpose or utility modifiers). Surfactants are one type of adjuvant that makes the herbicide more effective 

by increasing absorption into the plant, for example. Adjuvants also include selected oils, anti-foaming agents, 

buffering compounds, drift control agents, compatibility agents, stickers, and spreaders. Adjuvants (including 

surfactants) are not under the same registration guidelines as are herbicides. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 64

Adjuvants can be included as part of an herbicide product, or they can be packaged separately and mixed with an 

herbicide before application. Applicators follow adjuvant label instructions and warnings, and select adjuvants 

with low toxicity and low application volumes; in general, adjuvants compose a relatively small portion of the 

volume of herbicide applied. A national list of adjuvants approved for use on BLM lands is included in Appendix 

9. Specific risks from adjuvants to fish, wildlife, and human health are addressed in their respective resource 

sections in Chapter 4.

Three specific adjuvants currently or previously used by the BLM have been identified as toxic – NPE, R-11, and 

POEA. A Risk Assessment has been completed for one commonly used non-ionic surfactant type, nonylphenol 

polyethoxylate (NPE) (Bakke 2003). NPE is formed through the combination of ethylene oxide with nonylphenol 

(NP), and may contain small amounts of un-reacted NP. NP and NPE are weakly estrogenic in aquatic and 

terrestrial organisms (1000 to 100,000 times weaker than natural estrogen). NP and NPE are not toxic to soil 

microbes. NP is toxic to many aquatic organisms (EPA 2007b).

The adjuvant R-11 is a nonylphenol ethoxylate that is acutely toxic to aquatic life (Stark and Walthall 2003) and 

is suspected to be an endocrine-disrupting chemical (Bakke 2003). The BLM has suspended the use of R-11 in its 

herbicide applications and it is not evaluated further here. 

The adjuvant polyoxyethyleneamine (POEA) is an adjuvant present in some formulations of glyphosate, and is 

toxic to fish. It was present in the glyphosate evaluated for the Risk Assessments, and thus risks ratings on the 

Risk Assessment summary tables at the end of this Chapter include the risk from POEA.

Inert compounds (also called “other ingredients”) are those that are intentionally added to a formulation to aid 

in handeling or application, but are not intended to affect the target species. These ingredients are added to the 

formulation to facilitate its handling, stability, or mixing. Inert ingredients are not currently listed on the label. 

Although confidential business information protects the identity of inert ingredients, they were made available 

for the nine BLM-evaluated herbicides during preparation of the PEIS. Of those, none were on the EPA’s toxicity 

List 1 or 2, Inert Ingredients of Toxicological Concern and Potentially Toxic Inert Ingredients respectively. 

Twelve were on List 3, Inerts of Unknown Toxicity (some of these may have moderate to high potential toxicity), 

and over 50 were on List 4, Inerts of Minimal Toxicity. As described in Chapter 1, the EPA has embarked on 

rulemaking that would make the identity of other ingredients more public.

Impurities are inadvertent contaminants in the herbicide usually present because of the manufacturing process. 

Some have the potential to be of toxicological concern. Risk Assessments, however, examine commercial 

formulations so many effects from impurities (and manufacturer-included adjuvants and inerts) should be 

reflected in the risk categories displayed at the end of this Chapter. 

Differences in the Number of Herbicides Proposed East and West of the Cascades

Under Alternatives 3 and 4, districts east and west of the Cascades identified different program needs. Differences 

in the number of herbicides available on the east and west of the Cascades under these alternatives are based 

on differences in native vegetation types and invasive plant occurrence, management objectives, environmental 

conditions such as fire risk, and the prevalence of watercourses west of the Cascades. For example, a persistent, 

soil-applied herbicide could be used along roadsides east of the Cascades to remove fire-prone dry grasses, while the 

same herbicide would not be used west of the Cascades because the risk of roadside grass fires is low, bare ground in 

roadside borrow ditches would erode, and roadside applied persistent herbicides might end up in nearby streams.
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

65

Aerial Application

Aerial application is prohibited under Alternatives 3 and 4 west of the Cascades for a variety of reasons. The 

high density of streams, seeps, and other water bodies, coupled with dense vegetation, can make water difficult 

to avoid. Nearly all lands west of the Cascades are within source water protection areas for public water systems 

(Figure 4-6), and there are an uncountable number of individual domestic water intakes. Steep varied terrain 

coupled with tall vegetation (including dead trees) can force pilots to fly relatively high, increasing the risk of 

drift to water, non-target plants, and other non-target areas, and making surface waters harder to see from the air. 

There are also fewer large monocultures of invasive plants on the west side proposed for herbicide treatments.

Provision for Adding Herbicides in the Future 

Additional herbicides beyond the 18 included in the Record of Decision for the PEIS could become available 

for BLM use in the future if: 1) they are registered by the EPA for use on one or more of the Oregon land 

types1; 2) the BLM (nationally) determines that the benefits of use on public lands outweigh the risks to human 

health and the environment; 3) they meet the evaluation criteria to ensure that the decision to use the active 

ingredient is supported by scientific evaluation through human health and ecological risk assessments and NEPA 

documentation; and, 4) they are included in appropriate site-specific analysis. These evaluation criteria and 

how they are processed at the National level are discussed in more detail in Appendix 4. Aminopyralid (e.g., 

Milestone®) has been suggested by numerous BLM offices as the next candidate to be considered for this process. 

No “future” herbicide is assumed or analyzed in this EIS.

A previously unknown invasive plant species or the development of a resistant patch of weeds could indicate a need 

for one of the 18 herbicides not included in the selected alternative. Since the 18 herbicides have been analyzed in 

the PEIS and in this EIS under Alternative 5, additional statewide programmatic analysis would be unnecessary. 

Potential use of these herbicides would be addressed at the appropriate scale in site-specific NEPA. For example, the 

noxious weed giant salvinia can only be controlled with diquat, which would not be available if Alternative 4 were 

the selected alternative. Giant salvinia has not been found in Oregon or a neighboring state. If it were to be found at 

a single site in Oregon, it could be addressed in site-specific analysis supplementing this EIS. 

Assumptions and Information about Treatment Acres

Integrated Vegetation Management

Most BLM and BLM-authorized vegetation management is done by, or in support of, rangeland management, 

forest management, riparian management, wildlife and fisheries management, wildland fire management, and/

or the maintenance of infrastructure. Types of herbicide treatments that may be conducted in support of these 

programs under one or more of the alternatives include invasive weed control, habitat improvement, habitat 

improvement for Federally Listed and other Special Status species, restoration of riparian habitats, hazardous 

fuels reduction, and the control of vegetation encroachment into rights-of-way and other developments. The 

BLM’s overarching vegetation management goal is:

Through an interdisciplinary collaborative process, plan and implement a set of actions that improve 

biological diversity and ecosystem function and which promote and maintain native plant communities that 

are resilient to disturbance and invasive species. Healthy functioning plant communities will enhance the 

ability to attain economic benefits on public lands (PEIS:2-1).

1 Forestland; rangeland; riparian or aquatic; oil, gas, and mineral sites; rights-of-way; and, recreation and cultural sites 

(see Table 3-1 for more information).
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 66

The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) directs Federal agencies to use an integrated 

pest management approach to manage pests (including vegetation), stating “Integrated Pest Management is a 

sustainable approach to managing pests by combining biological, cultural, physical, and chemical tools in a way 

that minimizes economic, health, and environmental risks” (7 U.S.C. § 136r-1).

In order to control and manage invasive plants and unwanted vegetation, BLM uses an Integrated Vegetation 

Management approach. This approach involves the use and coordination of a variety of management techniques 

that are guided by numerous BLM and Department of the Interior manuals2. These include BLM Handbook 

H-1740-2, Integrated Vegetation Management (USDI 2008a); BLM Manual 9015, Integrated Weed Management 

(USDI 1992b); BLM Manual 9011, Chemical Pest Control, (USDI 1992c); BLM Manual 9014 Use of Biological 

Control Agents of Pests on Public Lands (USDI 1990); BLM Manual 9220 Integrated Pest Management3 (USDI 

1981); Department of the Interior Manual 517 DM 1, Pesticides, Integrated Pest Management Policy (USDI 

2007c); and, 609 DM Weed Control Program (USDI 1995b). 

Planning and Analysis

In Oregon, each BLM district prepares a planning document in compliance with NEPA and BLM Manual 9015 

that outlines the Integrated Vegetation Management actions they will be conducting. These weed management 

plans place an emphasis on preventing the establishment and spread of new infestations through pre-project 

surveys, prevention stipulations, early detection and responding rapidly to new infestations. In addition to the 

districts’ weed management plans, during all NEPA planning processes for ground disturbing projects and projects 

that have the potential to alter plant communities, the districts are required to assess the risk of introducing 

noxious weeds.4 If, through this analysis, it is determined that there is a moderate or high risk of spread, the 

districts are required to identify actions to be taken to reduce or prevent the spread of noxious weeds and to 

conduct monitoring after the completion of the project to prevent noxious weed establishment on previously 

uninfested sites (USDI 1992b). 

In Oregon, each BLM district has also identified a natural resource specialist with responsibility for managing the 

invasive plants and implementing the district’s Integrated Vegetation Management strategy. These specialists help 

ensure that invasive plant management issues and concerns are integrated into all of BLM’s programs, policies, 

and actions. 

2 Manuals are updated so specific actions or language referenced in this section could change. It is not expected that the 

overall use of an Integrated Vegetation Management approach would be removed.

3 Integrated Vegetation Management is a subset of integrated pest management, so for this EIS the terms are essentially 

interchangeable.

4 Other invasive plants should also be included in this analysis, but current handbook direction does not require it.

The goal of Integrated Vegetation Management is to prevent the spread of noxious weeds and other 

invasive plants, to eradicate early-detected noxious weed species in areas where certain weeds have 

not yet become established, and to control weeds where they have become established (PEIS:2-3). It is 

important to understand the entire Integrated Vegetation Management approach, because it is only in this 

context that the proposal to increase the number of available herbicides must be viewed. The Integrated 

Vegetation Management components described in this section will continue to apply to whichever 

alternative is selected. 
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

67

Prevention and Education

One of the most important elements of the BLM’s Integrated Vegetation Management approach is raising internal 

and external awareness of the threats of invasive plants and unwanted vegetation and promoting prevention 

actions. This includes conducting trainings for the public, employees, and contract personnel that teach weed 

identification, prevention, and effective control techniques. The BLM is actively involved in outreach efforts to 

raise awareness through such means as coordination and cooperation with the Oregon Department of Agriculture, 

counties, Cooperative Weed Management Areas, the Cooperative Extension Service, and others to create and 

present educational materials, brochures, traveling weed information displays, and other education materials. 

Prevention techniques that are encouraged or required include equipment and vehicle washing, avoiding entry into 

infested areas, and using weed-free seed, hay, and other materials. Additionally, districts are directed to prepare 

Weed Prevention Schedules annually to outline weed prevention practices and responsibilities. BLM cooperates 

with the State for weed prevention and control. Prevention and early detection programs have been shown to 

have benefit-cost ratios as high as 30:1 and more (Radke and Davis 2000).

Early Detection Rapid Response 

The BLM places a management emphasis on preventing the establishment of invasive plants into weed-free areas. 

BLM trains employees to identify invasive plants and to report new infestations so they can be addressed as 

quickly as possible. The objective is to prevent the weeds from becoming established and spreading. 

In areas where noxious weeds are established, the Oregon Department of Agriculture classifies them as either Class 

A or Class B, and they are managed based on that classification (USDI 1992b). Class A weeds are non-native, have 

a limited distribution, and pose a serious threat to landscape function. Class A weeds receive the highest priority 

for management with the objective of complete control or eradication. Class B weeds are also non-native and are 

determined to be potentially harmful, but they may be more common in some regions of the State. The goal is to 

control the spread of Class B weeds, decrease their population size, and eliminate the weed if possible. 

The BLM uses this weed classification system along with the Federal Noxious Weed List (USDA 2006c) and 

county weed lists to help prioritize their treatments. Other factors that influence which infestations are going to 

receive treatment include the aggressiveness of the weed species, the size of the infestation, the threat it poses to 

the surrounding ecosystem, and the BLM’s potential to be effective in treating the infestation. 

Early detection rapid response efforts increase the likelihood that invasions will be addressed successfully while 

populations are still localized and population levels are not beyond that which can be contained and eradicated. 

Adding an invasive plant to the State’s noxious weed list is not immediate; early detection and rapid response 

frequently targets invasive weeds before they are listed as noxious.

Coordination with Partners

The BLM works closely with private landowners, county weed boards, watershed councils, soil and water 

conservation districts, Cooperative Weed Management Areas, State agencies and other Federal agencies in 

an effort to increase weed prevention and treatment effectiveness. These close working relationships allow 

for technology and information sharing, more accurate weed inventories, the identification of monitoring and 

research needs, more effective outreach and control treatments, and a more efficient use of limited resources in the 

management of weeds. 
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 68

State and County Level Coordination

The BLM is required to coordinate project plans with State and local agencies under several acts, including the 

Clean Air Act, the Sikes Act, FLPMA, and Section 106 of the National Historic Preservation Act. The BLM 

coordinates closely with State resource management agencies on issues involving the management of public 

lands, the protection of fish and wildlife populations, (including Federally and State Listed threatened and 

endangered species), noxious weeds and other invasive plants, fuels and wildland fire management, and herbicide 

application. Herbicide spills are coordinated with State and local water quality agencies to ensure emergency 

actions and cleanup comply with applicable water quality standards, and do not result in unacceptable surface or 

ground water contamination. 

Local and State agencies work closely with the BLM to manage weeds on local, State, and Federal lands, 

and often conduct weed treatments on public lands. The BLM participates in exotic plant pest councils, State 

vegetation and noxious weed management committees, State invasive species councils, county weed districts, 

and Cooperative Weed Management Areas found throughout the State. Most Oregon counties have a weed 

management program and official contact person. The Oregon Department of Agriculture Weed Control Program 

coordinates closely with the BLM, Forest Service, and others in the listing of noxious weeds, and serves as the 

primary lead in setting control priorities in the State.

The Healthy Forests Restoration Act directs the Forest Service and BLM to develop an annual program of work 

for Federal land that gives priority to authorized hazardous fuel reduction projects that provide for protecting 

at risk communities or watersheds. The recommendations made by Community Wildfire Protection Plans are 

taken into account by the agencies in accordance with Healthy Forests Restoration Act, which gives priority in 

allocating funding to communities that have adopted these plans, or that have taken measures to encourage willing 

property owners to reduce fire risk on private property. 

Cooperative Weed Management Areas

Cooperative Weed Management Areas (CWMAs) are composed of local, private, State, and Federal interests. 

CWMAs typically center on a particular watershed or similar geographic area in order to pool resources and 

management strategies in the prevention and control of weed populations. Much of the BLM’s on-the-ground 

invasive plant prevention and management is done directly or indirectly through CWMAs. The BLM participates 

in numerous CWMAs throughout Oregon.

Treatment Methods

The Department of the Interior integrated pest management policy states that, “Bureaus will accomplish pest 

management through cost-effective means that pose the least risk to humans, natural and cultural resources, and 

the environment” and requires bureaus to “[e]stablish site management objectives and then choose the lowest risk, 

most effective approach that is feasible for each pest management project” (USDI 2007c), and “Determine, for 

each target pest, the possible courses of action and evaluate relative merits for controlling the pest with the least 

adverse effects on the environment” (Chemical Pest Control Handbook, BLM Manual 9011 - USDI 1992c). 

In treating noxious weeds, the BLM has a variety of tools available including the use of traditional Stateapproved biological controls (such as the use of insects, parasites, and pathogens that reduce the vigor, 

competitiveness and/or reproductive capacity of the noxious weed), the use of manual and mechanical methods 

(such as hand-pulling, mowing or tilling), burning, seeding or planting species that compete with the weeds, 

and the application of herbicides. Selection of a vegetation treatment method is based upon several parameters, 

which may include the following:
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

69

• management program/objective for the site; 

• historic and current conditions;

• opportunities to prevent future problems; 

• opportunities to conserve native and other non-invasive vegetation; 

• effectiveness and cost of the treatment methods;

• success of past restoration treatments or treatments conducted under similar conditions or 

recommendations by local experts;

• characteristics of the target plant species, including size, distribution, density, life cycle, and life stage in 

which the plant is most susceptible to treatment;

• non-target plant species that could be impacted by the treatment; 

• land use of the target area;

• proximity to communities;

• slope, accessibility, and soil characteristics of the treatment area; 

• weather conditions at the time of treatment, particularly wind speed and direction, precipitation prior to or 

likely to occur during or after application, and season;

• proximity of the treatment area to susceptible areas, such as wetlands, streams, or habitat for plant or 

animal species of concern;

• potential impacts to humans and fish and wildlife; or,

• need for subsequent revegetation and/or restoration. 

Herbicides are often the most effective control method:

• on pure stands of a single weed where desirable and non-target plants are scarce or absent;

• for rhizomatous weed species that would otherwise require repeated cutting or pulling for control;

• on plants whose characteristics make them difficult or impossible to remove with non-herbicide methods5;

• in areas where non-herbicide methods are cost prohibitive;

• in areas where non-herbicide methods have unacceptable adverse impacts to native plants;

• in areas where heavy soil disturbance is not acceptable;

• for species located in remote areas or limited access where non-herbicide methods are not feasible; or,

• in combination with other control treatments (for example, woody species like saltcedar, Russian olive, 

and Siberian elm can be controlled by cutting stems close to the ground in the fall and then spraying or 

wiping the stems with an herbicide registered for this use). 

In those instances where it is determined that the use of herbicides is the most appropriate tool to treat noxious 

weeds or other unwanted vegetation, BLM districts prepare a Pesticide6 Use Proposal (PUP) and complete or 

reference the environmental analysis that analyzes the effects of the type of treatment being proposed. The PUP 

and associated NEPA analysis document the relative merits of controlling the noxious weed using other methods, 

describes why the use of herbicides is the most appropriate treatment method, and, if applicable, how it will be 

used as part of an overall Integrated Vegetation Management strategy for that site (for example, an area may be 

sprayed with an herbicide this year and it will be followed up with hand pulling of any weeds found the following 

growing season) (USDI 1992c). The PUP identifies and describes the location of the area to be treated, the target 

species, and the herbicide and application rate and method to be used, as well as describing all anticipated impacts 

to non-target species and susceptible areas. It also evaluates the relative benefits to be derived from the use of 

5 For example, Canada thistle root fragments readily resprout.

6 A pesticide is any substance that is used to control, prevent, destroy, repel, or mitigate a pest. This includes herbicides, 

insecticides, rodenticides, and fungicides. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 70

the herbicide against the potential risks posed by their use. Completed PUPs are submitted through the District 

Manager to the Oregon State Office for review and approval. All herbicides are applied by certified applicators7. 

A Pesticide Application Record is completed within 24 hours of the application documenting environmental 

conditions at the time of treatment as well as actual herbicide use, treatment method, equipment used, and 

personnel present. 

Restoration 

Weed control plans should include a strategy for rehabilitating the site to prevent reoccurrence of the invasive 

plant to the greatest extent possible. Passive restoration or rehabilitation after control of small infestations 

usually involves allowing surrounding native plants to reseed or grow to reoccupy the site. Seeding or planting is 

generally an element of larger invasive weed control projects, or may be used as a prevention treatment following 

disturbances where invasive plants are anticipated. The season and nature of any site disturbance associated with 

the weed control effort should be designed to favor the recovery of desirable natives and discourage reinvasion 

with weeds. Minimizing site disturbances is one reason to select herbicide use over mechanical or other methods. 

Monitoring

Appendix 3 describes implementation and effectiveness monitoring requirements from BLM Manual Section 

9011. Implementation monitoring may also be specified in the local Resource Management Plan and/or the 

Biological Assessment or Opinion associated with the project. Implementation monitoring may be accomplished 

by: reviewing the Pesticide Application Records (PAR) completed at the time of treatment; comparing the PAR 

with the Pesticide Use Proposal (described above) or project NEPA decision; or, reviewing the PAR to ensure 

compliance with all Standard Operating Procedures and mitigation measures. The PAR documents the actual rate, 

time, and location of application as well as other factors and considerations, allowing a determination of whether 

actual application was consistent with plans and requirements documented in the site-specific NEPA decision 

or Pesticide Use Proposal. The 9011 Handbook also provides technical guidance on post-treatment evaluations 

for pesticide applications to occur within two years of treatment (USDI 1992c). Effectiveness monitoring can 

be formal or informal and typically compares vegetation characteristics of a site before and after treatment. 

Effectiveness monitoring typically includes recommendations for additional monitoring and weed control actions. 

See Appendix 3 for additional information about existing and potential monitoring.

Reporting

The Pesticide Application Records for applications on BLM lands are compiled by the BLM and used to develop 

State, National, and Environmental Protection Agency summaries and reports.

Herbicide Treatment Methods

Department of the Interior policy states, “[W]here it is determined the use of herbicides is the most effective tool 

choose the lowest risk, most effective approach that is feasible for each pest [and manage] through cost-effective 

means that pose the least risk to humans, natural and cultural resources, and the environment” (USDI 2007c).

7 Non-motorized application of non-restricted herbicides may be done by uncertified personnel if they are working under 

the supervision of a certified applicator. See Assumptions about Herbicide Treatments later in this Chapter for more 

information.
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

71

Herbicide application methods depend upon: the treatment objective (eradication, containment, or reduction); 

accessibility, topography, and size of the treatment area; characteristics of the target species and the desired (nontarget) vegetation; location of susceptible areas and potential environmental impacts in the immediate vicinity; 

anticipated costs; equipment limitations; and meteorological and vegetative conditions of the treatment area at the 

time of treatment. 

Herbicide application schedules are designed to minimize potential impacts to non-target plants and animals, 

while meeting the objective of the vegetation treatment program. The application timing and rates depend upon 

the target species, the presence and condition of non-target vegetation, soil type, depth to the water table, presence 

of other water sources, the label requirements, health risks, and other factors.

Herbicides can be applied with a variety of methods. Table 3-2 shows different methods, along with the percent 

that they have been used in the past. This is expected to change under the action alternatives with the addition of 

imazapic for treating large areas infested with invasive annual grasses; see the Treatment Acres, Gross Acres and 

Net Acres, and Pounds of Herbicides to be Applied section later in this Chapter for more information.

Table 3-2. Herbicide Application Methods on BLM Lands in Oregon

Herbicide Application Method

Percent of 

Total Use

(2000-2007)

Aerial 7%

Helicopter 5%

Fixed Wing 2%

Ground Application 93%

Back pack foliar spray 39%

ATV / UTV / Truck off-road 33%

ATV / UTV / Truck on an existing road 20%

Cut stump / wick / wipe / hack and squirt 2%

Herbicides can be applied aerially with helicopters or 

fixed-wing aircraft8. Operation of helicopters is more 

expensive than operation of fixed-wing aircraft, but 

helicopters are more maneuverable and can fly closer 

to the ground over uneven terrain. Helicopters also are 

more effective for treating target vegetation in areas with 

multiple vegetation types. Between 2000 and 2007, 

application by helicopter accounted for approximately 5 

percent of herbicide application on BLM lands in Oregon, 

and fixed-wing aircraft accounted for about 2 percent. All 

of these applications were east of the Cascades. Herbicides 

are applied aerially in areas that are hard to reach by 

ground (because of terrain or remote access) and in areas 

where the expanse of a monoculture of invasive weeds 

can be best controlled by this broadcast method (e.g., 

treatments of medusahead east of the Cascades).

8 Aerial application is not permitted west of the Cascades under Alternatives 3 and 4. Standard Operating Procedures 

and PEIS Mitigation Measures prohibit aerial application of certain herbicides like sulfometuron methyl.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 72

All other herbicide application on BLM lands in Oregon has been 

done by ground application. Thirty-nine percent of herbicides on 

BLM lands in Oregon are applied with a backpack foliar sprayer. This 

is usually done only in small areas, in areas inaccessible by vehicle, 

and in areas where weeds are scattered. A backpack sprayer is used 

because it can target specific plants, so that effects to non-target 

species can be kept to a minimum. Backpack sprayers are generally 

levered not motorized.

Herbicides may also be basally applied with a spray bottle, 

wick (wiped on), or wand (sprayed on). Herbicides can be 

applied to trees around the circumference of the trunk on the 

intact bark (basal bark), to cuts in the trunk or stem (frill, or 

“hack and squirt”), to cut stems and stumps (cut stump), or 

injected into the inner bark. From 2000-2007, these types 

of spot treatment methods accounted for approximately 2 

percent of herbicide application on BLM lands in Oregon. 

The remainder (about 53 percent) of herbicide application on BLM 

lands in Oregon has been done with spreaders or hand-held sprayers 

attached to vehicle-mounted tanks. Spray tank sizes vary from 15-25 

gallons on an all-terrain vehicle (ATV) or utility vehicle (UTV), to 100 

or more gallons on a truck. Using a large tank provides the advantage 

of less loading and mixing of herbicides, which, in turn, 

leads to less accidental spills and a more accurate rate of 

application. About three-fifths of ATV /truck applications 

have been done off-road with a hand-held sprayer attached 

to a small tank, and the remaining two-fifths on an existing 

road, trail, or right-of-way. Most of these applications have 

been spot treatments (e.g., hand-held sprayers connected by 

hose to the tank); fewer have been done with spreaders or 

booms. Under Alternatives 4 and 5, there would likely be 

an increase in boom applications from an ATV or truck, and 

a corresponding decrease in mowing along roadways.
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

73

Non-Herbicide Treatment Methods

This EIS addresses making various herbicides 

available to BLM’s existing vegetation 

management program. Non-herbicide 

treatments are already addressed in Resource 

Management Plans and related project NEPA analyses, and discussed in the National Vegetation Treatments 

Programmatic Environmental Report (PER). However, to assist in cumulative effects analyses, descriptions 

of non-herbicide treatment methods are included here. (Non-herbicide treatment acres for invasive plants are 

included on Table 3-3)

As with herbicide application methods, the type of non-herbicide treatment method chosen depends on 

the treatment objective (eradication or reduction); accessibility, topography, and size of the treatment area; 

characteristics of the target species and the desired vegetation; location of susceptible areas and potential 

environmental impacts in the immediate vicinity; anticipated costs; equipment limitations; meteorological and 

vegetative conditions of the treatment area at the time of treatment; and, other factors.

This EIS defines manual methods as non-motorized; all mechanical methods include motorized equipment. 

Manual methods such as pulling, digging, and grubbing weeds, can be used to control some invasive plants, 

particularly if the population is relatively small. These techniques can be extremely specific, minimizing 

damage to desirable plants and wildlife species, but they are generally labor and time intensive. Treatments must 

typically be administered several times annually to prevent the weed from re-establishing. In the process, laborers 

may trample vegetation and disturb soil, providing prime conditions for re-invasion by the same or other invasive 

plants. Manual techniques can be effective for small infestations and/or where a large pool of labor is available. 

They can be used in combination with other techniques, for example, when shrubs are pulled and cut, and resprouts and seedlings are treated with herbicides or fire several weeks or months later (Tu et al. 2001).

An indeterminate percentage (less than 

one percent) of treatments might be done 

by horseback. This would likely occur in 

areas where ATV access was not practical 

(e.g., susceptible habitat, Wilderness areas, 

areas with steep terrain), but where a larger 

tank size was needed. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 74

Mechanical methods include weed whackers, chainsaws, chaining, blading, disking, and mowing, including flail 

mowing, and boom mowers. Some of these methods (e.g., chainsaws and weed whackers) can be more targetspecific than others; all methods share some of the drawbacks that manual methods do (need of repeat treatment, 

disturbed vegetation and soil disturbance can promote invasive weeds, disturbance to non-target species, etc). 

These methods are the typical methods currently used along rights-of-way. Mechanical treatments in rights-ofway have the potential to spread a small invasive plant infestation across many miles.
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

75

When using mechanical and manual 

methods, all equipment and clothing is 

normally cleaned and inspected before being 

moved off-site. This lessens, but does not 

eliminate, the possibility of spreading the 

weed(s) to the next worksite.

Directed Livestock can reduce weed 

abundance at a particular site. However, 

grazing will rarely, if ever, eradicate 

invasive plants. Grazing animals may be 

particularly useful in areas with limited 

access, severe slopes, or where herbicides 

cannot be applied (e.g., near water). 

Animals are brought into an infested area 

at a time when they will be most likely to 

damage the invasive plants without causing 

unacceptable damage to the desirable 

species or environment. An example would 

be to time livestock grazing of cheatgrass 

prior to emergence of native grasses so the 

native grasses can grow in the absence of 

cheatgrass competition. 

Some animals do not graze uniformly, but 

can be focused in a specific area with the 

use of fences, molasses, or salt licks (Tu et 

al. 2001). Targeted grazing usually does 

not kill the plants, just suppresses growth, 

spread, and reproduction. It can be used in 

addition to seeding to restore native habitat. 

As with many other treatments, directed 

livestock can be most effective when used in 

combination with other treatments.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 76

Biological Control (biocontrol) is the 

use of non-native insects, pathogens, or 

other organisms to feed upon, parasitize, 

or otherwise interfere with a targeted 

weed species. Plant-eating insects, 

nematodes, mites, or pathogens can be 

effective at killing or weakening weed 

species. They often keep the weed in 

balance when they occur in the original 

native community from where the weed 

originated. Absence of these natural 

community controls is often what 

allows a weed to spread and become 

invasive in its new habitat. Introducing 

control agents is strictly managed because they have inherent risks to the ecosystem. Most of the species used 

for biological control are host-specific and are not known to attack non-target species. Biological controls will 

seldom remove an invasive plant entirely, but can dampen its reproduction, spread and extent, and keep it in some 

sense of balance compared to other plants in that community. Ideally, biocontrol agents are host-specific and will 

die once they kill their host. However, some biocontrol programs have resulted in irreversible harm to untargeted 

(non-pest) organisms and to ecological processes (Tu et al. 2001). Introduced (alien) biocontrols are always 

vigorously tested by the Federal Animal and Plant Health Inspection Service and approved by the State before 

use is allowed, to ensure that they are not likely to become pests themselves. Table A7-2 in Appendix 7 indicates 

noxious weeds targeted for biocontrol treatments.

The most effective prescription fires for weed 

control are typically those administered just 

before flower or seed set, or at the young seedling/

sapling stage. Like other treatments, timing is 

critical and is dependent on characteristics of 

the weed, desirable plants, soil moisture, and 

environmental conditions. Other treatment 

methods are often used in conjunction with fire, 

including the use of herbicides and/or seeding. In 

some cases, prescribed burns can unexpectedly 

promote an invasive, particularly when their 

seeds are adapted to fire, or when they resprout 

vigorously. Most successful weed control efforts 

using burning include native plant seeding and the 

restoration of historical (natural) fire regimes.

Invasive plants often move into places where the native vegetation has been 

disturbed by vehicles, fire, grazing, herbicide treatments, etc. Revegetation 

of a disturbed site is a key component of weed management, particularly 

when a site does not have a suitable seed source to establish healthy 

functioning vegetation. Seeding and planting can be used to control 

weed problems by establishing the desired plant species. It is often used 

as a follow up to other treatment methods or as a preventative treatment 

following wildfire (Colorado Natural Areas Program et al. 2000).
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

77

Treatment Acres, Gross Acres and Net Acres, and Pounds of Herbicides to be Applied

Treatment Acres – All Methods

Estimates of the number of acres to be treated annually with each herbicide and non-herbicide methods under 

each alternative are displayed in Table 3-3. Estimates are shown in acres so that they can be compared to each 

other and to other non-herbicide treatments. They were developed by district experts having knowledge of 

local treatment histories and of existing and expected invasive plant and other vegetation control needs, and 

assuming current budget trends. However, as with acreage projections in the PEIS, the estimates presented in 

Table 3-3 are approximate and used only as a guide for the analysis. The accuracy of estimates is limited by the 

uncertain nature of future invasive weed spread rates, and by uncertainties about future program funding and 

emphasis. Estimates for the Reference Analysis and Alternatives 1 and 2 are probably more precise than those 

for Alternatives 4 and 5, in part because portions of Alternatives 4 and 5 rely on funding sources not currently 

directed toward invasive plant control. All estimates were rounded upward to help ensure future use was 

adequately analyzed. The estimates are projected to apply for the next 10 to 20 years. Actual annual treatment 

levels could also vary from year to year based on changes in program emphasis or priorities, fluctuations in annual 

budgets, opportunities for cost savings with partnerships, and the availability of external funding. 

Table 3-3. Estimated1 Annual Treatment Acres West/East7 of the Cascades for Each Alternative.

Herbicide

Reference 

Analysis: No 

use of herbicides

Alt 2 (No 

Action): Use 

4 herbicides to 

treat noxious 

weeds

Alt 3: Use 12-

13 herbicides to 

control invasive 

weeds and pests 

and diseases

Management 

objective: 

vegetation 

treatment in 

rights-of-way, 

admin. sites, and 

recreation sites 

under Alt. 4

Management 

objective: 

vegetation 

treatment for 

habitats in 

Conservation 

Strategies under 

Alt. 4

Alt 4: 

(Proposed 

Action) Use 13-

16 herbicides to 

control invasive 

weeds, pests 

and diseases, 

and meet other 

management 

objectives2

Alt 5: Use 

18 herbicides 

to control 

vegetation

Herbicides Currently Approved for use on BLM Lands in Oregon (for noxious weed control only)

2, 4-D NA W: 1800

E: 6700

W: 2100

E: 1900

W: 200

E: 700

W: 100

E: 600

W: 2300

E: 3100

W: 2300

E: 5200

Dicamba NA W: 100

E: 4500

W: 200

E: 800

W: 100

E: 600

W: 0

E: 100

W: 200

E: 1400

W: 200

E: 1400

Glyphosate NA W: 5200

E: 700

W: 2300

E: 400

W: 300

E: 1000

W: 200

E: 100

W: 2700

E: 1300

W: 2700

E: 1300

Picloram NA W: 200

E: 3600

W: 400

E: 1100

W: 100

E: 200

W: 0

E: 1300

W: 500

E: 2500

W: 500

E: 2500

Additional Herbicides Proposed for Use in One or More of the Action Alternatives

Bromacil NA NA NA W: NA 

E: 700

W: NA 

E: 0

W: NA 

E: 900

W: 100

E: 900

Chlorsulfuron NA NA W: NA 

E: 3300

W: NA 

E: 900

W: NA 

E: 0

W: NA 

E: 4100

W: 100

E: 4100

Clopyralid NA NA W: 300

E: 1400

W: 0

E: 700

W: 100

E: 0

W: 300

E: 2000

W: 300

E: 2000

Diflufenzopyr + 

Dicamba NA NA NA NA NA NA W: 100E: 100

Diquat NA NA NA NA NA NA W: 100

E: 100

Diuron NA NA NA W: 100

E: 1200

W: 0

E: 0

W: 100

E: 1300

W: 100

E: 1300

Fluridone NA NA W: 200

E: 100

W: 0

E: 0

W: 0

E: 0

W: 200

E: 100

W: 200

E: 100
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 78

Herbicide

Reference 

Analysis: No 

use of herbicides

Alt 2 (No 

Action): Use 

4 herbicides to 

treat noxious 

weeds

Alt 3: Use 12-

13 herbicides to 

control invasive 

weeds and pests 

and diseases

Management 

objective: 

vegetation 

treatment in 

rights-of-way, 

admin. sites, and 

recreation sites 

under Alt. 4

Management 

objective: 

vegetation 

treatment for 

habitats in 

Conservation 

Strategies under 

Alt. 4

Alt 4: 

(Proposed 

Action) Use 13-

16 herbicides to 

control invasive 

weeds, pests 

and diseases, 

and meet other 

management 

objectives2

Alt 5: Use 

18 herbicides 

to control 

vegetation

Hexazinone NA NA W: 100

E: 100

W: 200

E: 100

W: 100

E: 0

W: 200

E: 100

W: 200

E: 100

Imazapic NA NA W: 500

E: 11000

W: 100

E: 400

W: 100

E: 2300

W: 500

E: 13500

W: 500

E: 15500

Imazapyr NA NA W: 1200

E: 300

W: 500

E: 100

W: 100

E: 600

W: 1600

E: 1000

W: 1600

E: 1100

Metsulfuron methyl NA NA W: 500

E: 2000

W: 100

E: 400

W: 0

E: 100

W: 600

E: 2300

W: 600

E: 2300

Sulfometuron 

methyl NA NA W: 100 E: 400

W: 0 

E: 500

W: 100 

E: 100

W: 100 

E: 900

W: 200

E: 900

Tebuthiuron NA NA NA W: NA 

E: 100

W: NA 

E: 300

W: NA 

E: 300

W: 100

E: 800

Triclopyr NA NA W: 1500

E: 700

W: 600

E: 800

W: 100

E: 700

W: 2200

E: 1900

W: 2300

E: 2200

Total Herbicide3 NA W: 7000

E: 9700

W: 8000

E: 22300

W: 1900

E: 7400

W: 200

E: 5500

W: 10000

E: 35200

W: 10200

E: 39800

Mechanical4 W: 4100

E: 1000

W: 3300

E: 200

W: 3000

E: 200

See Management of Native and Other Non-Invasive Vegetation

later in this Chapter9

Manual4 W: 2900

E: 600

W: 2000

E: 200

W: 2000

E: 200

Rx Fire4

 (Invasive 

Weed Control)

W: 600

E: 3100

W: 600

E: 5100

W: 400

E: 12100

Biocontrol4

,

5 W: 200

E: 200

W: 200

E: 100

W: 100

E: 100

Directed Livestock4 W: 100

E: 8700

W: 100

E: 2700

W: 100

E: 2700

Seeding or planting4 W: 1100

E: 20100

W: 1300

E: 16300

W: 1400

E: 21400

Total 

Treatments3,6,8 W: 8600

E: 33500

W: 13400

E: 32100

W: 14600

E: 43800

1

 Numbers rounded up to the nearest 100.

2

 Management objectives in this case refer to vegetation treatment in rights-of-way, administrative sites, and recreation sites, and treatment 

for habitats in Conservation Strategies. Alternative 4 combines Alternative 3 with these management objectives; however, columns may 

not add due to rounding, and the ability to use additional herbicides under Alternative 4 that are not available under Alternative 3. 3 Totals are not the total of the acres in the column. This is because:

•	 Tank mix treatments using two or more herbicides mixed together are shown as acres for each herbicide used, but the total would reflect 

the area of that treatment; or, 

•	 Treatments could be performed on the same acre multiple times a year (e.g., spraying and then seeding), and the total counts those acres once. 4

 Non-herbicide treatments only include estimated acreage of noxious weeds and invasive plants. Alternatives 4 and 5 treat other native 

vegetation, and no attempt was made to estimate non-herbicide treatments of other vegetation. See Management of Native and Other 

Non-Invasive Vegetation later in this Chapter. 5

 Biocontrol numbers indicate releases, not acres.

6

 Totals for the Reference Analysis and Alternatives 2 and 3 are for invasive plants only.

7 West of the Cascades is indicated with a W; east of the Cascades is indicated with an E.

8 Acres are gross acres rather than net acres. 

9 Non-herbicide invasive plant treatments would continue under Alternatives 4 and 5 as described in Alternative 3. Treatments of native 

vegetation with herbicides would replace some non-herbicide treatments and this is described in the Management of Native and Other 

Non-Invasive Vegetation section later in this Chapter.
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

79

Gross Acres and Net Acres

Gross acres are the area within which the plants are treated; the net acres are the actual area covered by the target 

plants where herbicide is applied. An example from the Klamath Falls Resource Area Pesticide Application Records 

(PAR) 1,414 gross project acres and less than 15 net acres spot treated. Other treatments may have a ratio of 1:1. 

Internal BLM reporting requires that all herbicide application to be reported as a minimum of one acre; that is, treating 

one plant is reported as treating one acre, treating 1⁄4 acre is reported as 1 acre, and treating 1 acre is reported as 1 acre. 

Examples of treatments from Pesticide Application Records (PAR)

Example 1: Herbicide treatments on European beachgrass following an 80-acre mechanical treatment (bulldozer 

and disc) where the distribution of re-sprouting beachgrass is 

relatively uniform across the treatment area (tending towards 

a monoculture). The PAR indicates that a tractor mounted 40’ 

boom completed the treatment in 4 hours and with a total of 

78 acres treated.

Gross acres = 80; Net acres = 78

Example 2: Scotch broom along 2 miles of road where 

clusters of plants are seldom separated by more than 10 feet. 

The width of the treatment area averages 20 feet. The PAR 

indicated that a crew of three with a truck mounted tank and 

two hand sprayers completed treatment in five hours and 

reported two acres of treatment.

Gross acres = 5 acres; Net acres = 2 acres

Example 3: Medusahead rye sprouting following a late 

summer burn in a uniform pattern across the area (tending 

towards a monoculture, with an absence of desirable grasses 

and forbs). Fire maps indicate there are 8,100 acres within the 

35,000-acre burn with these characteristics. Aerial application 

is selected as the most effective method to complete this largescale treatment. The PAR indicates 19 hours of airtime with 

total treatment acreage of 7960 acres.

Gross acres 8100; Net acres = 7960

Example 4: A 43-acre area has an infestation of dyer’s woad. 

The PAR states that approximately 800 plants were treated by 

a crew of three using backpack sprayers in an 8-hour period, 

with a total of 11 acres treated within the treatment area.

Gross acres = 43; Net acres 11

Example 5: A seasonal wetland (dry) contains a 114-acre 

infestation of perennial pepperweed. The PAR indicates 

approximately 2,300 plants were treated in an 6 hour period 

with a spray buggy and 20’ boom, with a total of 37 acres 

treated within the infestation.

Gross acres = 114; Net acres = 37
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 80

Pounds of Herbicide to be Applied

BLM and Forest Service Risk Assessments analyze a typical rate of application and a maximum rate of 

application. Maximum rates are the pounds per acre that can be sprayed, and are defined by the EPA and printed 

on the herbicide product label or are set by BLM policy. Typical rates vary by application type, and may be 

different for the BLM than those for lawn care companies or agricultural companies. These additional herbicides 

are often more effective at lower dosages; while acres of herbicides applied go up between Alternative 2 (No 

Action) and Alternative 3, total pounds of herbicides decrease substantially. Table 3-4 shows typical (for wildland 

use) and maximum rates for each herbicide, and the estimated annual pounds that each would total under each 

alternative (based on the estimated annual treatment acres shown on Table 3-3). PEIS Mitigation Measures limit 

use of some herbicides to their typical rate (where feasible) (see Table 3-4 footnote).

Table 3-4. Estimated Annual Pounds of Herbicides that Would be Applied at Typical and Maximum

Application Rates East/West of the Cascades for Each Alternative.

Herbicide

lbs/acre 

at typical 

rate

lbs/acre at 

maximum 

rate

Alternative 2 

(No Action) Alternative 3 Alternative 4(Proposed Action) Alternative 5

lbs at typical 

rate

lbs at max. 

rate

lbs at 

typical rate

lbs at max. 

rate

lbs at 

typical rate

lbs at max. 

rate

lbs at typical 

rate

lbs at max. 

rate

Herbicides Currently Approved for use on BLM Lands in Oregon (for noxious weed control only)

2, 4-D 1.0 1.91 W: 1800

 E: 6700 

W: 3420

 E: 12730 

W: 2100

 E: 1900 

W: 3990

 E: 3610 

W: 2300

 E: 3100 

W: 4370

 E: 5890 

W: 2300

 E: 5200 

W: 4370

 E: 9880 

Dicamba 0.3 2.0 W: 30

E: 1350 

W: 200 

E: 9000 

W: 60 

E: 240 

W: 400 

E: 1600 

W: 60 

E: 420 

W: 400 

E: 2800 

W: 60 

E: 420 

W: 400 

E: 2800 

Glyphosate 2.0 7.0 W: 10400 

E: 1400 

W: 36400 

E: 4900 

W: 4600 

E: 800 

W: 16100 

E: 2800 

W: 5400 

E: 3000 

W: 18900 

E: 10500 

W: 5400 

E: 3000 

W: 18900 

E: 10500 

Picloram 0.35 1.0 W: 70 

E: 1260 

W: 200 

E: 3600 

W: 140 

E: 385 

W: 400 

E: 1100 

W: 175 

E: 875 

W: 500 

E: 2500 

W: 175 

E: 875 

W: 500 

E: 2500 

Additional Herbicides Proposed for Use in One or More of the Action Alternatives

Bromacil 4.0 12.0 NA NA NA NA W: NA 

E: 3600 

W: NA W: 400 

E: 3600 

W: 1200 

E: 10800 E: 10800 

Chlorsulfuron 0.056 0.25 NA NA W: NA 

E: 185 

W: NA 

E: 825 

W: NA 

E: 230 

W: NA 

E: 1025 

W: 6 

E: 230 

W: 25 

E: 1025 

Clopyralid 0.35 0.5 NA NA W: 105 

E: 490 

W: 150 

E: 700 

W: 105 

E: 700 

W: 150 

E: 1000 

W: 105 

E: 700 

W: 150 

E: 1000 

Diflufenzopyr + 

Dicamba 0.2625 0.43752 NA NA NA NA NA NA W: 26 

E: 26 

W: 44 

E: 44 

Diquat 1.0 4.0 NA NA NA NA NA NA W: 100 

E: 100 

W: 400 

E: 400 

Diuron 6.0 20.0 NA NA NA NA W: 600 

E: 7800 

W: 2000 

E: 26000 

W: 600 

E: 7800 

W: 2000 

E: 26000 

Fluridone 0.15 1.3 NA NA W: 30 

E: 15 

W: 260 

E: 130 

W: 30 

E: 15 

W: 260 

E: 130 

W: 30 

E: 15 

W: 260 

E: 130 

Hexazinone 2.0 4.0 NA NA W: 200 

E: 200 

W: 400 

E: 400 

W: 400 

E: 200 

W: 800 

E: 400 

W: 400 

E: 200 

W: 800 

E: 400 

Imazapic 0.0313 0.1875 NA NA W: 16 

E: 344 

W: 94 

E: 2063 

W: 16 

E: 423 

W: 94 

E: 2531 

W: 16 

E: 485 

W: 94 

E: 2906 

Imazapyr 0.45 1.25 NA NA W: 540 

E: 135 

W: 1500 

E: 375 

W: 720 

E: 450 

W: 2000 

E: 1250 

W: 720 

E: 495 

W: 2000 

E: 1375 

Metsulfuron 

methyl 0.03 0.15 NA NA W: 15 E: 60 

W: 75 

E: 300 

W: 18 

E: 69 

W: 90 

E: 345 

W: 18 

E: 69 

W: 90 

E: 345 

Sulfometuron 

methyl 0.14 0.38 NA NA W: 14 E: 56 

W: 38 

E: 152 

W: 14 

E: 126 

W: 38 

E: 342 

W: 28 

E: 126 

W: 76 

E: 342 

Tebuthiuron 0.5 4.0 NA NA NA NA W: NA 

E: 150 

W: NA W: 50 

E: 400 

W: 400 

E: 1200 E: 3200 

Triclopyr 1.0 10.0 NA NA W: 1500 

E: 700 

W: 15000 

E: 7000 

W 2200 

E: 1900 

W: 22000 

E: 19000 

W: 2300 

E: 2200 

W: 23000 

E: 22000 

Estimated annual total lbs: W: 12300 

E: 10710 

W: 9320 

E: 5510 

W: 12038 

E: 22657 

W: 12734

E: 25541 

Shading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 1

 The 2,4-D Risk Assessment used a maximum rate of 4 lbs/acre. However, at the National level, BLM is limited to 1.9 lbs/acre.

2

 The maximum label rates are 0.4375 lbs/acres for oil and gas sites, rights-of-way, and recreation. The maximum label rates for rangeland are 0.35 lbs/acre.
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

81

Pesticide Use Reports

The annual Pesticide Use Reports (PURs)9 for 2006-2008, shown in Table 3-5, show actual statewide net acres, 

gross acres, and pounds of herbicides used. The percent of typical and maximum rate decreased in 2008 in part 

because the PEIS Record of Decision lowered the rates from those in previously applicable direction10. 

Pest and Disease Control in Alternative 3

Herbicide use in Alternative 3 would be limited to noxious weeds and other invasive plants, and to an estimated 

250 acres per year to treat native vegetation in State-identified control areas as necessary to stop non-native pests 

and diseases. Because these treatments are so incidental to the main theme of Alternative 3, and represent less 

than one percent of the total herbicide use proposed for Alternative 3, many references to Alternative 3 describe it 

as being limited to the control of invasive plants. 

Assumptions about Herbicide Treatments

Most invasive weed treatments target new species, new or small populations of existing species, and advancing 

edges of larger populations in order to keep weeds from infesting new drainages and other geographic areas (see 

Noxious Weeds and Other Invasive Plants section in Chapter 4). In addition, most weed treatments are spot 

9 The PUR is the compilation of the PARs at the State level for EPA reporting.

10 Typical and maximum rates were previously set by the May 1991 Final EIS for Vegetation Treatments on BLM Lands 

in Thirteen Western States for districts east of the Cascades, and the December 1985 Northwest Area noxious Weed 

Control Program EIS for districts west of the Cascades.

Table 3-5. 2006-2008 Oregon BLM Pesticide Use Reports Summary

Herbicide

Acres Lbs of Herbicides

Net acres Gross Acres

Net as % of 

Gross

Lbs of 

Herbicides

Percent of 

Typical Rate

Percent of

Maximum Rate

2008

2,4-D 4,341 6,493 67% 6,812 105% 55%

Dicamba 1,017 2,031 50% 937 185% 23%

Glyphosate 5,248 5,290 99% 2,302 22% 6%

Picloram 4,433 5,895 75% 2,477 120% 42%

total 15,039 19,709 76% 12,528

2007

2,4-D 3,573 5,167 69% 7,737 150% 79%

Dicamba 1,227 2,521 49% 1,264 201% 25%

Glyphosate 2,859 2,931 98% 1,569 27% 8%

Picloram 1,151 1,617 71% 1,118 197% 69%

total 8,810 12,235 72% 11,688

2006

2,4-D 2,729 3,634 75% 6,022 166% 87%

Dicamba 636 1,303 49% 641 197% 25%

Glyphosate 3,038 3,075 99% 2,606 42% 12%

Picloram 780 1,232 63% 766 177% 62%

total 7,128 9,244 78% 10,035
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 82

treatments directed at specific plants, and non-target damage is limited to the immediately surrounding area, if it 

happens at all. However, some acres are so infested with weeds (particularly annual grasses such as cheatgrass 

and medusahead, or weeds such as purple loosestrife or spotted knapweed) that they have become a monoculture. 

Monocultures are often broadcast treated with booms.

Sites that are too heavily infested with weeds for spot treatments are less likely to be treated with herbicides 

unless there are broader objectives requiring an unusually large investment, such as Federally Listed or other 

Special Status species’ habitat, campground, designated special area, and so forth. If site management objectives 

make treatment of heavily infested sites worthwhile, those same objectives will dictate the use of selective 

herbicides and extra effort to retain native plants, and/or prompt restoration.

Table 3-2 (Herbicide Application Methods on BLM Lands in OR) earlier in this Chapter shows types of 

application methods, and at what rate (percentage) they have been used under the current program. The use of 

additional herbicides and additional vegetation treatment as described in the action alternatives would change 

those application rates. Under Alternative 3, cheatgrass and medusahead (invasive annual grasses that have 

infested more than 5 million acres in Eastern Oregon) would often be best controlled by aircraft application on 

the acres where desirable and non-target plants are absent or sparse (e.g., after large fires where these grasses are 

expected to dominate). Vegetation surrounding the perimeter of the infestation would likely be more varied, and 

herbicide application on the perimeter would likely happen on the ground. Table 3-6 shows the expected aerial 

and ground application percentages for each alternative.

Table 3-6. Ground and Aerial Herbicide Application

Application Method

Herbicide Application

Alt 2 (No 

Action)

Alternatives 3, 41

, and 5 Alternatives 41 and 5 Alternative 5

Imazapic 

treatments 

east of the 

Cascades 

(primarily for 

controlling 

medusahead 

and 

cheatgrass)

All other 

herbicide 

treatments 

under Alt 3

Management 

objective: 

vegetation 

treatment in 

rights-of-way, 

admin. sites, 

and recreation 

sites under 

Alt. 41

Management 

objective: 

vegetation 

treatment for 

habitats in 

Conservation 

Strategies 

under Alt. 41

Additional 

treatments 

proposed 

under Alt 5

Aerial2 7% 90% 7% 2% 7% 7%

Ground 93% 10% 93% 98% 93% 93%

1

 Alternative 4 is the Proposed Action

2

 Aerial applications would be only allowed east of the Cascades under Alternatives 3 and 4.

Under Alternatives 2 and 3, herbicide application would happen with methods that would seek to avoid all nontarget vegetation; that is, native (non-invasive) vegetation would be avoided with the use of selective herbicides or 

selective application methods. Under Alternatives 4 and 5, some applications would be to control all vegetation 

in administrative sites and recreation sites, which would likely change application selectivity. Under power lines 

west of the Cascades, a goal is to establish low growing vegetation and to prevent tree re-sprouting. This would 

most likely be done with spot or selective treatments. However, on roads, application would likely be performed 

by a truck with a mounted sprayer, as the goal would be to remove most vegetation, including vegetation 
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

83

invading pavement edges and vegetation that limits visibility. Most treatments on administrative or recreation 

sites would be spot treatments; however, some would use application methods and herbicides that would remove 

all vegetation. Habitat improvements, allowed under Alternatives 4 and 5, would be selective in order to keep 

desired vegetation.

Total treatment acres are similar under the Reference Analysis and Alternative 2; most acres that would be treated 

with herbicides under Alternative 2 (No Action) would be treated through other methods under the Reference 

Analysis. Fire would increase by more than 300 percent and manual and mechanical methods would increase by 

about 150 percent. 

Herbicide treatment acres are estimated to increase by 13,600 acres annually (nearly double the acres) between 

Alternatives 2 and 3, but use of the four herbicides available under Alternative 2 (No Action) would decrease 

52 to 83 percent under Alternative 3. A majority of the increase in Alternative 3 is because of the availability of 

imazapic, which would be used on an estimated 11,500 acres annually, primarily east of the Cascades, to control 

monocultures of invasive annual grasses such as cheatgrass and medusahead. These acres are shown as an 

estimated annual average; at least some of the imazapic use would be to prevent invasive grass reinvasion after 

major fires and a 50,000-acre treatment every 6 or 8 years would be a possible scenario. It would also be used 

to reduce invasive grass fuels hazards in the wildland urban interface around rural communities, and as part of a 

fire-imazapic-seeding restoration treatment. Monocultures of invasive plants could be treated with a boom; the 

majority of the treatments under Alternative 3 would be done with selective methods. Seeding and planting and 

prescribed fire would increase significantly between Alternatives 2 and 3. These acres would often be duplicative 

to acres of herbicide treatments and would be part of restoring invasive weed monocultures to native vegetation.

Alternative 4 (the Proposed Action) would, in addition to invasive plant treatments, add 2,000 acres annually 

west of the Cascades and 12,800 acres annually east of the Cascades. One-third of this would be for habitat 

improvements in Conservation Strategies; the remainder would be for administrative site, right-of-way, and 

recreation site treatments. Right-of-way treatments would usually be accomplished by the permit holder (e.g., the 

power or pipeline owner).

Alternative 5 allows the use of herbicides for any objective other than livestock forage and timber production. 

The acres (200 acres annually west of the Cascades and 4,700 acres annually east of the Cascades) that could 

be treated under Alternative 5 but not under any other alternative are primarily additional habitat improvement 

projects (e.g., reducing western juniper encroachment into important sagebrush habitat).

Under all alternatives, about 50 percent of the 2,4-D acres shown on Table 3-3 would be at low doses (oz. per 

acre) as part of a tank mix with other herbicides.

Management of Native and other Non-Invasive Vegetation

In addition to invasive plant treatments listed for Alternative 3 on Table 3-3, Alternative 4 (Proposed Action) 

would permit the use of herbicides for native and other non-invasive vegetation treatments for rights-of-way, 

administrative sites, recreation sites, and limited habitat improvement treatments. Alternative 5 would allow 

the treatment of native vegetation for any objective except livestock forage or timber production. Herbicide 

treatments for native vegetation control would be 15,100 acres under Alternative 4 and 20,000 acres under 

Alternative 5 (see Table 3-7).
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 84

No attempt was made to quantify the total acres of non-herbicide native vegetation treatments already 

occurring on BLM lands in Oregon because such treatments cover a variety of objectives, are in the magnitude 

of a hundred thousand acres per year, and most are not affected by the alternatives. However, for the portion of 

those acres that would start being treated with herbicides under Alternatives 4 and 5, the following substitution 

assumptions would apply:

• For rights-of-way, administrative sites, and recreation sites, the BLM and cooperators have been 

accomplishing needed work with non-herbicide methods. The 9,300 acres proposed for herbicide use 

for these objectives under Alternatives 4 and 5 shown on Table 3-7 likely represent similar acres of nonherbicide treatments under the Reference Analysis and Alternatives 2 and 3 but are not included on Table 

3-3. For comparison purposes, it is assumed that 90 percent of this work is currently done mechanically; 

the majority of the acres are in road maintenance (cleared now with mowers) and power line rights-ofway (generally mowers or large trees cleared with chainsaws). The remaining 10 percent is accomplished 

manually (e.g., poison oak in campgrounds).

• Of the acres proposed for herbicide use to accomplish habitat improvement objectives under Alternative 4 

(Proposed Action) and various objectives under Alternative 5, about 35 percent would replace treatments 

already being done with non-herbicide methods (e.g., chaining western juniper), and 65 percent represent 

new opportunities (habitat treatments not currently being done because of high cost, unacceptable effects, 

or logistical issues). It is assumed that treatments currently being done through mechanical and manual 

means are in about the same proportion as treatments of invasive plants under Alternative 3: 60 percent 

mechanical, and 40 percent manual.

Table 3-8 shows the application of the above assumptions. However, because the total amount of native 

vegetation treated through non-herbicide means is unknown, the table only shows the change in how native 

vegetation is treated under each alternative. These numbers are not totals; they merely show how acreages 

increase or decrease in relation to the No Action Alternative (Alternative 2). For example, under Alternative 

4 (Proposed Action), 13,000 acres of native vegetation east of the Cascades would be treated with herbicides. 

Because of this, 7,905 acres would not be treated mechanically and 1,520 acres would not be treated manually. 

Under Alternative 3, which does not allow the treatment of native vegetation with herbicides11, those acres, and 

an unknown number of other acres, would continue to be treated with mechanical and manual methods. These 

numbers do not affect the acres of invasive plants treated through mechanical and manual means; invasive plant 

11 Except for pest and disease control in State-identified control areas.

Table 3-7. Estimated Annual Herbicide Treatment Acres under Alternatives 3, 41, and 5

Method

Invasive Plant 

Treatment Native Vegetation Treatment

Alternatives 

3,4,5 Alternative 3

Rights-of-way, 

administrative sites, 

and recreation sites 

(under Alternative 4)

Conservation 

Strategies

Total Alternative 

4 Alternative 5

West2 East2 West East West East West East West East West East

Herbicides 8,000 22,300 2503 2503 1,900 7,400 200 5,500 2,100 13,000 2,300 17,700

1 Alternative 4 is the Proposed Action

2 West/East of the Cascades

3

 Pest and disease control in State-identified control areas only.
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

85

treatments in Alternative 3 are assumed to remain constant through Alternatives 4 and 5.

Applicator Certification

Per BLM Policy, all herbicide application is carried out by certified applicators or under the direct supervision 

of a certified applicator. Certified applicators must attend pesticide training and successfully complete a 

comprehensive certification exam to receive a three-year certification. Certification is issued by the BLM’s 

National Office, and a roster of certified pesticide applicator personnel is maintained in the National Office (USDI 

1992c). In addition, the Oregon BLM hires contractors that are certified and licensed by the Oregon Department 

of Agriculture, Pesticides Division, which requires similar training and certification. 

Risk

EPA Labels

The Federal Insecticide, Fungicide and 

Rodenticide Act (FIFRA) establishes procedures 

for the registration, classification, and regulation 

of all herbicides. Before any herbicides may 

be sold legally, the EPA must register it. The 

EPA may classify an herbicide for general use if 

it determines that the herbicide is not likely to 

cause unreasonable adverse effects to applicators 

or the environment, or it may be classified for 

restricted use if the herbicide must be applied 

by a certified applicator and in accordance 

with other restrictions. The herbicide label is 

a legal document specifying allowable uses; 

Table 3-8. Estimated Change in Native Vegetation Annual Treatment Acres

Method

Total Native 

Vegetation 

treated under 

the Reference 

Analysis and 

Alternatives 2 

(No Action) and 

3 (No Action)

 Treatment 

of native 

vegetation on 

rights-of-way, 

administrative 

sites, and 

recreation 

sites under 

Alternative 4 

 Treatment 

of native 

vegetation for 

habitats as 

described in 

Conservation 

Strategies under 

Alternative 4 

Total Native 

Vegetation 

treated under 

Alternative 4

(Proposed 

Action)

 Additional 

Treatments 

allowed under 

Alternative 5 

 Total Native 

Vegetation 

treated under 

Alternative 5

West1 East West East West East West East West East West East

Herbicides 0 0 1900 7500 200 5500 2100 13000 200 4700 2300 17700 

Mechanical NA NA -1710 -6750 -42 -1155 -1752 -7905 -42 -987 -1794 -8892

Manual NA NA -190 -750 -28 -770 -218 -1520 -28 -658 -246 -2178

Net change in total 

native vegetation 

acres treated - - 0 0 130 3575 130 3575 130 3055 260 6630 

1 West / East of the Cascades

EPA terms

LD50 Lethal Dose to 50% of the population

LOC Level of Concern

NOAEL No Observed Adverse Effect Level

LOAEL Lowest Observed Adverse Effect Level

BLM terms

RQ Risk Quotient

ECC Estimated Exposure Concentration

TRV Toxicity Reference Value

ARI Aggregated Risk Index

Forest Service Terms

HQ Hazard Quotient

RfD Reference Dose

TI Toxicity Index
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 86

all applicators that apply herbicides on public lands (i.e., certified applicators or those directly supervised by 

a certified applicator) must comply with the application rates, uses, handling, and all other instructions on the 

herbicide label, and where more restrictive, the rates, uses, and handling instructions developed by the BLM.

In addition to sub-chronic and chronic toxicity, EPA herbicide registration looks at the acute toxicity of an 

herbicide. Acute toxicity is the most common basis for comparing the relative toxicities of herbicides. Acute 

toxicity can be measured by LD50

12. LD50 (LD = lethal dose) represents the amount of herbicide that results in the 

death of 50 percent of a test population. Therefore, the lower the LD50, the more toxic the herbicide. Table 3-9 

shows the three categories that the EPA uses for classifying herbicides (USDI 1992c).

In addition, the EPA has established Levels of Concern (LOC) 

for herbicides, which is the dose of the herbicide above which 

effects would be expected. The LOCs are used by EPA 

for registration, and to indicate potential risk to non-target 

organisms and the need to consider regulatory action (EPA 

2007c). In the absence of information indicating otherwise, the 

LOC is generally 1/10th of the Lowest Observed Adverse Effect 

Level (LOAEL); that is, the lowest dose level where there was 

a statistically significant increase in frequency or severity of 

adverse effects13 to the test organism. In some cases, no adverse 

reaction happens at any dose (or at any reasonable dose), and 

the LOC is the No Observed Adverse Effect Level (NOAEL). 

LOCs include uncertainty factors based on the amount and 

nature of the toxicity testing on which they are based.

Risk Assessments

One of the Purposes identified in Chapter 1 is: 6. Prevent herbicide control treatments from having unacceptable 

adverse effects to applicators and the public, to desirable flora and fauna, and to soil, air, and water. To help 

address this Purpose, this EIS relies on BLM and/or Forest Service-prepared Human Health and Ecological 

Risk Assessments for the 18 herbicides analyzed in this EIS. These Risk Assessments are included in this EIS 

as Appendix 8: Risk Assessments (uncirculated). The Risk Assessments are used to quantitatively evaluate the 

probability (i.e., risk) that herbicide use in wildland settings might pose harm to humans or other species in 

the environment. As such, they address many of the risks that would be faced by humans, plants, and animals, 

including Federally Listed and other Special Status species, from the use of the herbicides. The level of detail in 

the Risk Assessments far exceeds that normally found in EPA’s registration examination.

12 or LC50 (lethal concentration) in the case of aquatic organisms.

13 Lethal or sub-lethal.

Table 3-9. Herbicide Label Categories

Categories

Signal Word Required 

on Label

Oral LD50 (mg/

kg)

Dermal LD50

(mg/kg)

Inhalation LD50

(mg/kg)

Probable Oral Lethal Dose 

for 150 lb Human

I – Highly Toxic DANGER, POISON, 

skull & crossbones

Up to and 

including 50

Up to and 

including 200

Up to and including 

0.2

A few drops to a teaspoonful

II – Moderately 

Toxic

WARNING From 50 to 500 From 200 to 

2000

From 0.2 to 2 Over one teaspoonful to one 

ounce

III – Slightly 

Toxic

CAUTION From 500 to 5000 From 2000 to 

20,000

From 2 to 20 Over one ounce to one pint 

or one pound.

Acute toxicity: The quality or potential of 

a substance to cause injury or illness shortly 

after exposure through a single or short-term 

exposure.

Chronic toxicity: The ability of a substance or 

mixture of substances to cause harmful effects 

over an extended period, usually upon repeated 

or continuous exposure sometimes lasting for 

the entire life of the exposed organism. 
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

87

Risk is defined as the likelihood that an effect (injury, disease, death, or environmental damage) may result from a 

specific set of circumstances. It can be expressed in quantitative or qualitative terms. While all human activities 

carry some degree of risk, some risks are known with a relatively high degree of accuracy because data have been 

collected on the historical occurrence of related problems (e.g., lung cancer caused by smoking, auto accidents 

caused by alcohol impairment, and fatalities resulting from airplane travel). For several reasons, risks associated 

with exposure to herbicides (at least in wildland settings) cannot be so readily determined. The Risk Assessments 

help evaluate the risks resulting from these situations.

Risk Assessments are necessarily done on a surrogate species in laboratory conditions, identified to represent 

a species group, as toxicological data does not exist for most native non-target species. Survival, growth, 

reproduction, and other important sub-lethal processes of both terrestrial and aquatic non-target species were 

considered. Assessments considered acute and chronic toxicity data. Exposures of receptors14 to direct spray, 

surface runoff, wind erosion, and accidental spills were analyzed. 

Most of the Human Health and Ecological Risk Assessments were developed by the BLM for the 2007 PEIS, or 

by the Forest Service (FS) for the 2005 Pacific Northwest Region Invasive Plant Program EIS (see Table 3-10). 

Three Human Health Risk Assessments used in this EIS (bromacil, diuron, and tebuthiuron) were used in BLM’s 

1991 Vegetation Treatment on BLM Lands in Thirteen Western States EIS and recent literature has been examined 

to ensure these Risk Assessments remain current. The Risk Assessments, related separate analyses, and the PEIS 

includes analysis of degradates and other ingredients for which information is available and not constrained 

by confidential business information (CBI) restrictions. Preparing a risk assessment for every conceivable 

combination of herbicide, tank mix, adjuvants (including surfactants), and other possible mixtures is not feasible, 

as the BLM cannot prepare hundreds of risk assessments, and the cost would be exorbitant. To the degree a toxic 

substance is known to pose a significant human or ecological risk, the BLM has undertaken analysis to assess its 

impacts through Risk Assessments. More detailed information about uncertainty in the Risk Assessment process 

is included in Appendix 13.

When evaluating risks from the use of herbicides proposed in a NEPA planning document, reliance on EPA’s 

herbicide registration process as the sole demonstration of safety is insufficient. The U.S. Forest Service and BLM 

were involved in court cases in the early 1980s that specifically addressed this question (principally Save Our 

Ecosystems v. Clark, 747 F.2d 1240, 1248 (9th Cir. 1984) and Southern Oregon Citizens v. Clark, 720 F. 2d 1475, 

1480 (9th Cir. 1983)). These court decisions and others affirmed that although the BLM can use EPA toxicology 

data, it is still required to do an independent assessment of the potential risks of using herbicides rather than relying 

on FIFRA registration alone. The Courts have also found that FIFRA does not require the same examination of 

impacts that the BLM is required to undertake under NEPA. Further, Risk Assessments consider data collected 

from both published scientific literature and data submitted to EPA to support FIFRA product registration, whereas 

EPA utilizes the latter data only. The EPA also considers many wildland herbicide uses to be minor. Thus, the 

project-specific application rates, spectrum of target and non-target organisms, and specialized exposure scenarios 

evaluated by the BLM are frequently not evaluated by EPA in its generalized registration assessments.

The Risk Assessments are the source for much of the individual herbicide information presented in each of the 

resource sections in this EIS, including the high-moderate-low risk categories shown in tables. Individual Risk 

Assessment Tools are being developed for each herbicide, to assist field managers in translating risks to project 

design parameters. The use of those Individual Risk Assessment Tools is explained in Use of Individual Risk 

Assessment Tools During Implementation later in this Chapter.

14 An ecological entity such as a human, fish, plant, or slug.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 88

Table 3-10. Human Health and Ecological Risk Assessment Sources

Herbicide

Ecological Risk Assessments

Human Health Risk 

Assessments

2007 BLM 

PEIS1

2005 FS EIS2 (Ecological & 

Human Health)

2007 BLM 

PEIS1

1991 BLM EIS3

2,4-D4 √

Bromacil √ √

Chlorsulfuron √ √5

Clopyralid4 √

Dicamba √6 √

(Diflufenzopyr + dicamba) √

Diflufenzopyr √ √

Diquat √ √

Diuron √ √

Fluridone √ √

Glyphosate √

Hexazinone4 √

Imazapic √ √

Imazapyr √

Metsulfuron methyl √

Picloram √

Sulfometuron methyl √ √

Tebuthiuron √ √

Triclopyr √ 1 2007 PEIS: Risk Assessments developed for the 2007 Vegetation Treatments Using Herbicides on Bureau of Land Management 

Lands in 17 Western States Programmatic Environmental Impact Statement. 2

 2005 FS EIS: Risk Assessments developed for the 2005 Pacific Northwest Region Invasive Plant Program Final Environmental 

Impact Statement. These Risk Assessments cover both human health and ecological. 3

 1991 BLM EIS: Human Health Risk Assessments adopted with the 1991 Vegetation Treatments on BLM Lands Record of Decision, 

and originally developed for the Forest Service’s 1988 Managing Competing and Unwanted Vegetation Final Environmental Impact 

Statement as part of a Human Health Risk Assessments that covers 16 herbicides. 4

 The Risk Assessments used in the PEIS were updated and the most recent version has been used in this EIS.

5 The BLM prepared a chlorsulfuron Ecological Risk Assessment, so only the human health portion of the FS Risk Assessment was 

used in this EIS. 6 The BLM’s Ecological Risk Assessment only analyzes the use of dicamba in conjunction with diflufenzopyr. The BLM in Oregon 

plans to use dicamba without diflufenzopyr; hence, the Forest Service dicamba Risk Assessment was used for the ecological portion 

of the analysis.

 

Drift

Assuming non-target animals and plants are not directly sprayed, drift is the process most likely to result in 

herbicides getting onto non-target plants and animals, as well as getting onto non-target areas such as stream 

channels. Drift, defined as that part of a sprayed herbicide that is moved from the target area by wind while it is 

still airborne, is primarily dependent upon the elevation of the spray nozzle, droplet size and air movement. The 

smaller the droplet, the longer it stays suspended and the farther it can travel. Drift is one exposure scenario 

examined in the Risk Assessments and summarized on the risk tables at the end of this Chapter. 

Spray drift can be reduced by increasing droplet size since wind will move large droplets less than small droplets 

(Table 4-18). Droplet size can be increased by: 1) reducing spray pressure; 2) increasing nozzle orifice size; 

3) using special drift reduction nozzles; 4) using additives that increase spray viscosity; and, 5) using rearward 
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

89

nozzle orientation in aircraft. Commercial drift reduction agents are available that are designed to reduce drift 

beyond the capabilities of the determinants described above. These products create larger and more cohesive 

droplets that are less apt to break into small particles as they fall through the air. They reduce the percentage 

of smaller, lighter particles, which are most apt to drift. Standard Operating Procedures for air quality provide 

techniques for controlling drift, including specifying selection of equipment that produces 200-800-micron 

diameter droplets. 

Drift includes droplets and vapor. In general, however, herbicides have very low vapor pressures and BLM 

spray mixtures do not produce much vapor. One study showed that with more volatile insecticides, little or no 

vapor drift was detected 9-27 meters downwind for insecticides with vapor pressures less than 1x10-4 mm Hg 

(Woodward et al. 1997). All of the herbicides covered by the EIS have very low vapor pressures (maximum is 

4x10-6 mm Hg and they range to as low as 5.5x10-16 mm Hg; Vencill et al. 2002).

High, Moderate, and Low Risk in BLM and Forest Service Risk Assessments

The Risk Assessments attempt to measure both acute toxicity and chronic toxicity. Chronic toxicity is difficult to 

measure, especially in humans, but shows the results of sub-lethal doses that could result in cumulative deposits 

that could cause long-term problems in a vital body function. There is no standard measure for chronic toxicity.

BLM Ecological Risk Assessments

The BLM Ecological Risk Assessments established a Risk Quotient (RQ) for every herbicide and defined risk 

categories as follows: 

0 No Risk RQ < most conservative LOC for the species

L Low Risk RQ = 1 to 10 times the most conservative LOC for the species

M Moderate Risk RQ = 10 to 100 times the most conservative LOC for the species 

(generally equal to LOAEL to 10-times LOAEL)

H High Risk RQ > 100 times the most conservative LOC for the species

The RQ is calculated using the Estimated Exposure Concentration (EEC) and the Toxicity Reference Value 

(TRV). The EEC is the dose that an organism would be exposed to under the test scenario; e.g., consumption

would indicate the amount of herbicide eaten on a sprayed material (a cow eating only sprayed grass for a day, 

for example), direct spray indicates that the organism was sprayed directly with a wand or was in a flight path (a 

non-target plant species, for example). The TRV is the toxicity of the herbicide – usually the LOAEL or NOAEL. 

The RQ is the EEC divided by the TRV. An uncertainty factor can be brought in if it is thought that a species (or a 

particular individual within the species) is particularly susceptible to herbicide use, or that the single dose does not 

represent long-term exposure.

For example, the TRV (the dose that can be consumed with a potentially adverse effect) for a mule deer 

consuming vegetation contaminated with bromacil is 170 milligrams per kilogram of body weight per day (a mule 

deer weighs an estimated 70 kg). Assuming a daily consumption rate of 6.2 kg of forage, all contaminated with 

bromacil sprayed at the typical application rate (4 lbs/acre), the EEC (the amount of herbicide that the mule deer 

will be exposed to by eating the contaminated vegetation) is 33.7 milligrams per kilograms of body weight per 

day. Therefore, the RQ is 33.7 mg/kg divided by 170 mg/kg, or 0.198, which is a risk category of 0 (or no risk).

Tank Mixes - The BLM evaluated risks from mixing two herbicides together in a tank mix. The BLM assumed 

that products in a tank mix act in an additive manner. Therefore, to simulate a tank mix of two herbicides RQs 

for those two herbicides were combined (see Appendix 8; diquat, fluridone, and tebuthiuron are not generally 

tank mixed by the BLM and were not included in the analysis). The application rates within the tank mix are not 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 90

necessarily the same as those of each individual active ingredient applied alone. The percent of RQs exceeding 

LOCs for each of the ten BLM herbicide active ingredients was compared to the percent of RQs exceeding LOCs 

for tank mixes, to determine whether additional risks were predicted for tank mixes.

BLM Human Health Risk Assessments

The BLM Human Health Risk Assessments used the Aggregated Risk Index (ARI) and defined risk categories as follows:

0 No Risk Majority of ARIs > 1

L Low Risk Majority of ARIs < 1 but > 0.1

M Moderate Risk Majority of ARIs < 0.1 but > 0.01 

H High Risk Majority of ARIs < 0.01

The ARI is a formula for combining LOCs for all exposure avenues (oral, dermal, inhalation), each with different 

uncertainty factors, and comparing them with the exposure levels that would occur in the scenarios in the Risk 

Assessments. ARIs less than 1 indicate a concern from at least one of the exposure avenues (EPA 2001b:51-55). 

Forest Service Risk Assessments

The Forest Service Risk Assessments are very similar to the BLM’s. The Forest Service Risk Assessments 

established a Hazard Quotient (HQ) for every herbicide and established risk categories as follows: 

0 No Risk HQ < LOC for the species

L Low Risk HQ = 1 to 10 times the LOC1 for the species

M Moderate Risk HQ = 10 to 100 times the LOC for the species

H High Risk HQ > 100 times the LOC for the species

The HQ is calculated using the Reference Dose (RfD) and the Toxicity Index (TI). The RfD is the dose that an organism 

would be exposed to under the test scenario; the TI is the toxicity of the herbicide and the HQ is the RfD divided by the 

TI. An uncertainty factor can be brought in if it is thought that a species (or a particular individual within the species) is 

particularly susceptible to herbicide use, or that the single dose does not represent long-term exposure.

1

 As noted in the previous discussion, LOCs are generally set at 1/10th of the LOAEL. Thus, an HQ of 1 to 10 times LOC 

is equivalent to an HQ of 0.1 to 1 in the 2005 Forest Service Invasive Plant EIS (USDA 2005a:4-73). The Forest Service 

EIS goes on to explain “The threshold is intended to help reviewers distinguish moderate risks (HQ=2 to 10 [HQ = 20-100 in 

this EIS]), which could in most cases be mitigated through exposure-reducing project design criteria from significant health 

risks (HQ>10 [HQ>100 in this EIS]) that could be difficult to mitigate if Worst-Case situations occur at the project level. 

For specific situations where a HQ>10 [HQ>100 in this EIS] is identified, the specific physiologic effect and the relationship 

between the NOAEL and the LOAEL may be evaluated to more precisely determine whether a toxic effect is actually likely 

to occur (Durkin, personal communication).” (USDA 2005a:4-73).
Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

91

Figure 3-1 shows the basis for Risk Assessments, which consists of Figure 3-1. Basis for Risk Assessments

the following parts:

• Hazard Identification: what are the dangers inherent with 

the herbicide? (e.g., endocrine disruption, cancer causing, 

etc.)

• Exposure Assessment: who could come into contact and 

how much? (specific exposure scenarios)

• Dose Response Assessment: how much is too much? At 

what dose are observable effects observed?

• Risk Characterization: indicates whether or not there is a 

plausible basis for concern (HQ or RQ).

Stated another way, the lower range for the L, or low, risk category 

is theoretically the level at which an effect began to be discernable 

in testing or modeling (theoretically, because uncertainty factors 

have the effect of reducing the dose identified as having the adverse 

effect). The minimum identified effect may have been skin or 

eye irritation, leaf damage, and so forth. Uncertainty factors are added to address hypersensitive individuals, or 

accommodate uncertainties in the measurements, such as inferring effects to one species based on actual tests 

on other species. Uncertainty factors are typically multiples of 10, so the assumed Lowest Observable Effects 

(LOAEL) dose could have been inflated 10, 100, or even 1,000 times for uncertainties. Thus, exposure of the 

average individual to the dose identified as having an effect probably would not. Nevertheless, the L or low rating 

indicates risks start at that point. Moderate risk categories indicate risk starts at doses one-tenth those of the low 

ratings; high is one-hundredth of the testing scenario dose. Testing scenarios are severe – e.g., soaking the test 

animal – so Standard Operating Procedures and PEIS Mitigation Measures such as buffers, wind speed limits, 

and so forth, as well as required safety equipment, limit exposure to substantially less than tested doses. For 

herbicides with moderate and high risk categories for a particular receptor, special cautions are implemented. For 

example, buffers for Special Status plant species are as large as 1,500 feet for some herbicides (Table A2-1). The 

low, moderate, or high human health risk categories shown on Tables 3-16 through 3-21 are more conservative 

than the EPA ratings used to apply the Caution, Warning, or Danger/Poison signal words to herbicide labels.

The Risk Assessments are summarized on tables showing herbicide risk categories at maximum and typical 

application rates to vegetation, wildlife, and humans, in a variety of application scenarios. Tables 3-12 and 3-13 

show herbicide risks to vegetation, from BLM and Forest Service Risk Assessments respectively. Tables 3-14 and 

3-15 show herbicide risks to wildlife, fish, and aquatic invertebrates. Tables 3-16 and 3-17 show the risks to human 

health (worker and public, respectively) from herbicides analyzed with the PEIS. Table 3-18 and 3-19 show worker 

and public exposure scenarios for Forest Service-evaluated herbicides, and Tables 3-20 and 3-21 reflect the 1991 

BLM risk categories for the remaining worker and public human health scenarios. Further information about the 

Human Health Risk Assessments can be found in the Human Health and Safety section of Chapter 4. 

Uncertainty in the Risk Assessment Process

The Risk Assessments conducted by the BLM and Forest Service incorporate various conservative assumptions 

to compensate for uncertainties in the risk assessment process. Within any of the steps of the human health 

risk evaluation process, assumptions were made due to a lack of absolute scientific knowledge. Some of the 

assumptions are supported by considerable scientific evidence, while others have less support. Every assumption 

introduces some degree of uncertainty into the risk evaluation process. Regulatory risk evaluation methodology 

requires that conservative assumptions be made throughout the risk assessment process to ensure that public 

health is protected. This conservatism, both in estimating exposures and in setting toxicity levels likely led to an 

exaggeration of the real risks of the vegetation management program to err on the side of protecting human health 

and other species. 
 92

Vegetation Treatments Using Herbicides on BLM Lands in Oregon

Cumulative effects of long-term use of herbicides may have different outcomes than risk assessments can 

anticipate. Although identification of adverse effects from chronic exposures is one of the parameters examined 

in the risk assessment process, it is possible there are long-term sub-lethal effects on reproductive or migratory 

behavior from low concentrations of herbicides or additives that are not documented in the Risk Assessments.

See additional information about uncertainty near the end of Appendix 13.

Use of the Individual Risk Assessment Tools During Implementation

As noted in Appendix 2, site-specific analysis or Individual 

Risk Assessment Tools (IRATs) can be used to determine 

alternative ways to meet PEIS Mitigation Measure objectives. 

IRATs are one tool to assist in translating risks to project 

design parameters. IRATs are currently being developed for 

the BLM Risk Assessments, and are scheduled for completion 

in 2012. The IRATs create the ability to do project-specific 

risk assessments. Individual project parameters (information 

about herbicide application, workers, fish and wildlife, and 

native vegetation), can be input into the IRATs, which then 

calculate RQs and HQs. The IRATs isolate the computations 

from the discussions of the computations, and are intended 

as a tool to make risk assessment calculations easier to 

understand and review, allowing for more project specific 

mitigation measures. 

Toxicity Comparison with Household Products

It might help to put toxicity and risk in perspective to 

consider them in the context of risks associated with common 

household products. Herbicides are any agent used to kill 

plants or inhibit their growth. As such, they are designed to 

target highly specific biological or biochemical processes 

within plants, such as photosynthesis and production of 

branch-chain amino acids. Mammals (humans included) do 

not photosynthesize or produce branch-chain amino acids, so 

materials that target photosynthesis or branch-chain amino 

acid production have no place to bind in mammals. With no 

place to work, they are often excreted in urine within 24 hours 

of the exposure. This flushing of the herbicide does not allow 

concentrations to build up within the body to toxic levels. For 

these reasons, herbicides often have higher LD50 values than 

many commonly used or consumed products (Table 3-11) 

(Fishel et al. 2009).

Methodology for Assessing Effects

This analysis is tiered to, and borrows analysis from, the 2007 

Final Vegetation Treatments Using Herbicides of BLM Lands 

in 17 Western States Programmatic Environmental Impact 

Table 3-11. Comparison of oral LD50

values1 for commonly used herbicides and

consumer goods.

Chemical LD50

Nicotine 9

Caffeine 192

Bleach 192

Tylenol 338

Household ammonia (10%) 350

Codeine 427

Diquat 500-5,000

Triclopyr 600-1,000

Tebuthiuron 644

2,4-D 700

Hexazinone 1,000

Glyphosate 2,000-6,000

Dicamba 2,700

Table salt 3,000

Picloram 3,000-5,000

Diuron 3,750

Bromacil 4,000

Clopyralid 4,700

Diflufenzopyr >5,000

Imazapic >5,000

Imazapyr >5,000

Metsulfuron methyl >5,000

Chlorsulfuron 6,000

Fluridone >10,000

Alcohol 10,300

Vitamin C 11,900

Baking Soda 14,220

Sulfometuron methyl >17,000

Water 80,000

1

 LD50 calculated on rats, as milligrams of 

substance per kilogram of body mass.
93

Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis

Statement (PEIS). In addition, information was used from the Risk Assessments (see earlier in this Chapter, Appendix 

8, and Tables 3-12 through 3-21), the 2005 Forest Service Pacific Northwest Region Invasive Plant Program EIS 

(USDA 2005a), and other sources cited throughout the document. Effects consider implementation of BLM policy, 

Standard Operating Procedures, and PEIS Mitigation Measures. Effects in Chapter 4 consider the effects of:

• contact or ingestion of an herbicide;

• invasive plants; and,

• non-herbicide treatments.

Standard Operating Procedures, PEIS Mitigation Measures, Risk, and the Potential 

for Adverse Effects

The BLM has a long history with herbicides. As a result, numerous handbooks and other policy materials have 

been developed governing the use of these herbicides. For the PEIS, direction from these policies was gathered 

and labeled as Standard Operating Procedures (see Appendix 2). While the risks listed in Tables 3-12 through 

3-21 (and discussed in Chapter 4) are for unprotected exposures described in the Risk Assessments, effects 

conclusions for each resource described in the PEIS and this EIS are predicated on application of the Standard 

Operating Procedures or that a site-specific determination is made that their application is unnecessary to achieve 

their intended purpose and protection. 

The PEIS examined (and the Record of Decision selected) an alternative using 18 herbicides for a full range of 

vegetation treatment objectives in the 17 western states. CEQ regulations require an EIS to identify mitigation 

measures for all identified adverse effects, if they are available. The various resource sections in the PEIS all 

identify various levels of risk or adverse effects, and each section identified one or more mitigation measures. 

These were in addition to the Standard Operating Procedures. The Record of Decision for the PEIS adopted 

all of these mitigation measures. Like the Standard Operating Procedures, the PEIS Mitigation Measures are 

included in Appendix 2 and apply to all alternatives in this EIS. Since the alternatives in this EIS are subsets of 

the alternative selected by the Record of Decision for the PEIS, and all adverse effects identified by the PEIS were 

mitigated where practicable, there should be few or no adverse effects expected from implementation of any of 

the action alternatives in this EIS. That is essentially what the effects examination confirms. Most of the “effects” 

discussions in this EIS for the use of herbicides are, for the most part, identifications of risks identified by the Risk 

Assessments and other literature without Standard Operating Procedures and PEIS Mitigation Measures applied.

The potential for adverse effects from the use of herbicides are, in many of the resource sections in Chapter 4, 

expressed as zero or no, low, moderate, and high risk. These are quantified terms (see Risk Assessments earlier 

in this Chapter) summarizing the results of scenarios modeled by the Risk Assessments and summarized on 

Tables 3-12 through 3-21. Where Risk Assessment scenarios resulted in a moderate or high risk, that risk is 

reported in Chapter 4 as a potential adverse effect, or risk. It is important to understand, however, that such risks 

almost always generated corresponding PEIS Mitigation Measures during the PEIS process (if there were not 

already Standard Operating Procedures designed to avoid the adverse effects). Therefore, most of the potential

for adverse effects (or risks) discussed in Chapter 4 are followed by the conclusion that implementation of the 

Standard Operating Procedures, PEIS Mitigation Measures, and site-specific analysis (during which the Risk 

Assessments or Individual Risk Assessment Tools will be specifically consulted) should make the likelihood of 

actual adverse effects negligible, de minimus, or at worst “minimized”. Additional Conservation Measures in 

Appendix 5 apply to Federally Listed and proposed species and critical habitat.

Occasionally the resource sections will use unquantified comparison terms such as less than, slightly, lower, and 

greater. These are typically relative statements within the Risk Assessment-defined terms of low, moderate, and high. 
 94

Table 3-12. BLM-Evaluated

Herbicide Risk

Categories for

Vegetation

Application Scenario BROM1 CHLOR1 DIQUAT DIURON FLUR1 IMAZ1 OVER1 SULFM1 TEBU1 Typ2 Max2 Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max

Direct Spray Terrestrial plants

H3 H

H

H

H

H

M

H NE NE

L

M

M

H 0 L

M

H

[1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1]

Special status terrestrial plants

H

H

H

H

H

H

H

H NE NE

L

M

H

H

H

H

M

H

[1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1] [1:1]

Aquatic plants pond

H

H

M

M

H

H

H

H 0 0 L

L

M

M

H

H

L

M

[1:2] [2:2] [1:2] [2:2] [2:2] [2:2] [2:2] [2:2] [2:2] [2:2] [1:2] [2:2] [1:2] [1:2] [2:2] [2:2] [2:2] [2:2]

Aquatic plants stream

H

H

M

M

H

H

H

H 0 0 L

M

M

H

H

H

M

H

[2:2] [2:2] [2:2] [2:2] [2:2] [2:2] [2:2] [2:2] [2:2] [2:2] [2:2] [2:2] [1:2] [1:2] [2:2] [2:2] [1:2] [1:2]

Accidental Spill to a PondAquatic plants pond NE

H NE

H NE

H NE

H NE

L NE

H NE

M NE

H NE

H

[1:1] [1:2] [2:2] [1:1] [2:2] [2:2] [1:1] [2:2] [2:2]

Off-Site DriftTerrestrial plants

M

M

M

M

L

M 0 L NE NE 0 0 0 0 0 0 0 0 [3:6] [3:6] [5:12] [8:12] [7:12] [7:12] [5:6] [4:6] [18:18] [13:18] [5:6] [4:6] [12:12] [12:12] [6:6] [4:6]

Special status terrestrial plants

M

H

M

M

M

M

M

H NE NE 0 0 L

L

H

H 0 L

[3:6] [3:6] [7:12] [7:12] [7:12] [7:12] [3:6] [3:6] [17:18] [13:18] [3:6] [4:6] [5:12] [8:12] [5:6] [3:6]

Aquatic plants pond 0 L 0 0 NE NE

L

M NE NE 0 0 0 0 L

L 0 0

[9:12] [7:12] [24:24] [24:24] [8:12] [6:12] [36:36] [34:36] [12:12] [12:12] [13:24] [12:24] [12:12] [12:12]

Aquatic plants stream 0 L 0 0 NE NE

L

M NE NE 0 0 0 0 L

L 0 0

[8:12] [6:12] [24:24] [22:24] [6:12] [6:12] [36:36] [33:36] [8:12] [6:12] [14:24] [10:24] [12:12] [12:12]

Surface RunoffTerrestrial plants 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0 [42:42] [42:42] [42:42] [42:42] [42:42] [42:42] [42:42] [42:42] [42:42] [42:42] [42:42] [42:42] [42:42] [42:42]Special status terrestrial plants

0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0 [39:42] [38:42] [42:42] [42:42] [38:42] [34:42] [42:42] [42:42] [34:42] [33:42] [32:42] [28:42] [38:42] [34:42]

Aquatic plants pond

M

H 0 0 NE NE

M

H NE NE 0 0 0 0 L

L 0 L

[70:84] [45:84] [64:84] [53:84] [50:84] [64:84] [80:84] [62:84] [70:84] [67:84] [42:84] [38:84] [65:84] [55:84]

Aquatic plants stream 0 L 0 0 NE NE

L

L NE NE 0 0 0 0 0 0 0 0 [45:84] [55:84] [80:84] [77:84] [35:84] [39:84] [84:84] [83:84] [84:84] [84:84] [69:84] [60:84] [84:84] [74:84]

Wind ErosionTerrestrial plants 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0 [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9]Special status terrestrial plants

0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0 [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9] [9:9]

Aquatic plants pond NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NEAquatic plants stream NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NEShading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 1 BROM = Bromacil; CHLOR = Chlorsulfuron; FLUR = Fluridone; IMAZ = Imazapic; OVER = (Diflufenzopyr + dicamba) Overdrive®; SULFM = Sulfometuron methyl; and TEBU = Tebuthiuron.2 Typ = Typical application rate; and Max = Maximum application rate.3 Risk categories: = 0 = No risk (majority of RQs < most conservative LOC for non Special Status species); L = Low risk (majority of RQs 1-10x most conservative LOC for non Special Status species); M = Moderate risk (majority of RQs 10-100x most conservative LOC for non Special Status species); H = High risk (majority of RQs >100 most conservative LOC for non Special Status species); and NE = Not evaluated. The Risk Category is based on the risk level of the majority of risk quotients observed in any of the scenarios for a given exposure group and receptor type. See more information at the risk tables in Chapter 4 of the Ecological Risk Assessments (ENSR 2005b-k) to determine the specific scenarios that result in the displayed level of risk for a given receptor group. The number in brackets represents the number of RQs in the indicated risk category: number of scenarios evaluated.

Vegetation Treatments Using Herbicides on BLM Lands in Oregon
95

Table 3-13. FS-Evaluated

Herbicide Risk

Categories for

Vegetation

2,4-D Dicamba Clopyralid Glyphosate1 Hexazinone Imazapyr Metsulfuron Picloram Triclopyr1

Typ2 Max4 Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max

Terrestrial PlantsDirect spray, susceptible plants

H3 H

H

H

H

H

M

H

H

H

H

H

H

H

H

H

H

H

Direct spray, tolerant plants L L 0 0 0 L L M

M

M

M

M L M L M NE NE

Off-site drift, low boom, susceptible plants

0

[4:6]

L

[3:6]

L H L L 0 L L L L M L M

M

M L M

[3:6] [3:6] [4:6] [3:6] [5:6] [3:6] [3:6] [3:6] [4:6] [3:6] [4:6] [4:6] [3:6] [4:6] [3:6] [3:6]

Off-site drift, low boom, tolerant plants

0

[6:6]

0

[6:6]

0 0 0 0 0 0 0 0 0 0 0 0 0 0

NE NE

[6:6] [6:6] [6:6] [6:6] [6:6] [6:6] [6:6] [5:6] [6:6] [5:6] [6:6] [6:6] [6:6] [6:6]

Off-site drift, aerial, susceptible plants

0

[3:6]

M

[3:6]

M

H

H

[2:6]

M L M

M

[3:6]

M

[2:6]

M

H

M

H L M

M

H

[3:6] [3:6] [2:6] [3:6] [2:6] [2:6] [2:6] [2:6] [2:6] [3:6] [3:6] [2:6] [2:6]

Off-site drift, aerial, tolerant plants 0 [6:6]

0

[6:6]

0 0 0 0 0 0 0

[4:6]

L

[3:6]

0 0 0 0 0 0

NE NE

[6:6] [6:6] [6:6] [6:6] [6:6] [5:6] [4:6] [3:6] [5:6] [4:6] [6:6] [5:6]

Surface runoff, susceptible plants 0 [22:30]

0

[18:30]

0 0 0 0 0 0 0

[18:30]

0

[17:30]

0 0 0 0 0 0 M

H

[22:30] [22:30] [23:30] [23:30] [30:30] [30:30] [18:30] [18:30] [21:30] [18:30] [21:30] [22:30] [13:30] [13:30]

Surface runoff, tolerant plants 0 [30:30]

0

[30:30]

0 0 0 0 0 0 0

[22:30]

0

[22:30]

0 0 0 0 0 0

NE NE

[30:30] [30:30] [30:30] [30:30] [30:30] [30:30] [30:30] [30:30] [25:30] [22:30] [30:30] [27:30]

Aquatic PlantsAccidental spill, susceptible macrophytes L M NE NE

H

H

M

M

H

H

H

H

H

H 0 0 H

H

Accidental spill, susceptible algae

H

H

H

H L L NE NE

H

H

M

H

M

H

M

M

H

H

Accidental spill, tolerant algae L M 0 L 0 0 NE NE

H

H 0 0 L M 0 0 NE NE

Acute exposure, susceptible macrophytes 0 0 NE NE 0 0 0 0 M

H L L L L 0 L L M

Acute exposure, susceptible algae L M 0 L 0 0 NE NE

H

H 0 0 0 0 0 0 NE NE

Acute exposure, tolerant algae 0 0 0 0 0 0 NE NE L M 0 0 0 0 0 0 NE NE

Chronic exposure, susceptible macrophytes L L NE NE 0 0 0 0 M

M 0 0 0 0 0 0 0 L

Chronic exposure, susceptible algae

M

M 0 0 0 0 NE NE

M

M 0 0 0 0 0 0 NE NE

Chronic exposure, tolerant algae 0 0 0 0 0 0 NE NE 0 L 0 0 0 0 0 0 NE NE

Shading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 1 Risk categories for the more toxic formulations are presented here.2 Typ = Typical application rate; and Max = Maximum application rate. 3 0 = No risk (HQ < LOC); L = Low risk (HQ = 1 to 10 x LOC); M = Moderate Risk (HQ = 10 to 100 x LOC); H = High risk (HQ > 100 LOC); and NE = Not evaluated. Risk categories are based on upper estimates of hazard 

quotients and the LOC of 1.0. If more than one scenario is involved in an exposure pathway (i.e., off-site drift and surface runoff), then the number of scenarios with the given risk category (out of the total number of evaluated scenarios) is displayed in parentheses. The reported risk category is that of the majority of the HQs for all the scenarios. As a result, risk may be higher than the reported risk category for some scenarios within each category. For more information, see the individual Forest Service Risk Assessments. 4 The 2,4-D Risk Assessment used a maximum rate of 4 lbs/acre. However, at the National level, BLM is limited to 1.9 lbs/acre.

Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis
 96

Table 3-14. BLM-Evaluated

Herbicide Risk

Categories for

Wildlife, Fish, and

Aquatic

Species

Application Scenario BROM1 CHLOR1 DIQUAT DIURON FLUR1 IMAZ1 OVER1 SULFM1 TEBU1 Typ2 Max2 Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max

Direct SprayNon Special Status species

Small mammal – 100% absorption 03 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Pollinating insect – 100% absorption

L

L 0 0 L

L

L

M 0 0 0 0 0 0 0 0 0 0

Small mammal – 1st order dermal absorption 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Fish pond

L

L 0 0 L

L

M

M 0 0 0 0 0 0 0 0 0 0

Fish stream

L

M 0 0 L

M

H

H 0 L 0 0 0 0 0 0 0 0

Aquatic invertebrates pond 0 0 0 0 M

H

M

H 0 L 0 0 0 0 0 0 0 L

Aquatic invertebrates stream 0 L 0 0 H

H

M

H 0 L 0 0 0 0 0 0 L

M

Special Status species

Small mammal – 100% absorption 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Pollinating insect – 100% absorption

L

L 0 0 L

M

L

M 0 0 0 0 0 0 0 0 L

M

Small mammal – 1st order dermal absorption 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Fish pond

L

L 0 0 L

H

M

H 0 M 0 0 0 0 0 0 0 0

Fish stream

M

M 0 0 M

M

H

H 0 L 0 0 0 0 0 0 0 0

Aquatic invertebrates pond 0 0 0 0 M

H

M

M 0 H 0 0 0 0 0 0 L

L

Aquatic invertebrates stream 0 L 0 0 H

H

M

H 0 L 0 0 0 0 0 0 L

M

Indirect Contact with Foliage After Direct SprayNon Special Status species

Small mammal – 100% absorption 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Pollinating insect – 100% absorption 0 0 0 0 0 0 0 L 0 0 0 0 0 0 0 0 0 LSmall mammal – 1st order dermal absorption 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Special Status species

Small mammal – 100% absorption 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Pollinating insect – 100% absorption 0 0 0 0 0 L 0 L 0 0 0 0 0 0 0 0 0 LSmall mammal – 1st order dermal absorption 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ingestion of Food Items Contaminated by Direct SprayNon Special Status species

Small mammalian herbivore – acute 0 L 0 0 0 L 0 L 0 0 0 0 0 0 0 0 0 0Small mammalian herbivore – chronic 0 L 0 0 L

M

L

M 0 0 0 0 0 0 0 0 0 L

Large mammalian herbivore – acute 0 L 0 0 0 M 0 L 0 0 0 0 0 0 0 0 0 LLarge mammalian herbivore – chronic

L

M 0 0 L

M

M

H 0 0 0 0 L

M 0 0 0 L

Small avian insectivore – acute 0 0 0 0 0 M 0 L 0 0 0 0 0 0 0 0 0 LSmall avian insectivore – chronic 0 0 0 0 0 M 0 L 0 0 0 0 0 0 0 0 0 0Large avian herbivore – acute 0 0 0 0 0 L 0 L 0 0 0 0 0 0 0 0 0 0Large avian herbivore – chronic 0 L 0 0 L

H 0 M 0 0 0 0 0 0 0 0 0 0

Large mammalian carnivore – acute 0 L 0 0 0 L 0 0 0 0 0 0 0 0 0 0 0 0Large mammalian carnivore – chronic 0 0 0 0 0 0 L

L 0 0 0 0 0 0 0 0 0 0

Special Status species

Small mammalian herbivore – acute 0 L 0 0 0 L 0 L 0 0 0 0 0 0 0 0 0 MSmall mammalian herbivore – chronic 0 L 0 0 L

M

L

M 0 L 0 0 0 0 0 0 0 L

Large mammalian herbivore – acute 0 M 0 0 L

M 0 M 0 0 0 0 0 0 0 0 0 L

Large mammalian herbivore – chronic

L

M 0 0 L

M

M

H 0 0 0 0 L

M 0 0 0 L

Small avian insectivore – acute 0 0 0 0 L

M 0 L 0 0 0 0 0 0 0 0 0 0

Small avian insectivore – chronic 0 0 0 0 0 M 0 L 0 0 0 0 0 0 0 0 0 0

Vegetation Treatments Using Herbicides on BLM Lands in Oregon
97

Application Scenario BROM1 CHLOR1 DIQUAT DIURON FLUR1 IMAZ1 OVER1 SULFM1 TEBU1 Typ2 Max2 Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max

Large avian herbivore – acute 0 L 0 0 0 M 0 M 0 0 0 0 0 0 0 0 0 LLarge avian herbivore – chronic 0 L 0 0 L

H 0 M 0 0 0 0 0 0 0 0 0 0

Large mammalian carnivore – acute 0 L 0 0 0 L 0 L 0 0 0 0 0 0 0 0 0 0Large mammalian carnivore – chronic 0 0 0 0 0 0 L

L 0 0 0 0 0 0 0 0 0 0

Accidental Spill to PondNon Special Status species

Fish pond NE

M NE 0 NE

H NE

H NE

M NE 0 NE 0 NE 0 NE

L

Aquatic invertebrates pond NE

L NE 0 NE

H NE

H NE

H NE 0 NE 0 NE 0 NE

L

Special Status species

Fish pond NE

M NE 0 NE

H NE

H NE

M NE 0 NE 0 NE 0 NE

M

Aquatic invertebrates pond NE

M NE 0 NE

H NE

H NE

H NE 0 NE 0 NE 0 NE

L

Off-Site DriftNon Special Status species

Fish pond

L

L 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0

Fish stream

L

M 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0

Aquatic invertebrates pond 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0Aquatic invertebrates stream 0 L 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0

Special Status species

Fish pond 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0Fish stream 0 M 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0Aquatic invertebrates pond 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0Aquatic invertebrates stream 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0

Surface RunoffNon Special Status species

Fish pond 0 0 0 0 NE NE 0 L NE NE 0 0 0 0 0 0 0 0Fish stream 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0Aquatic invertebrates pond 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0Aquatic invertebrates stream 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0

Special Status species

Fish pond 0 0 0 0 NE NE 0 L NE NE 0 0 0 0 0 0 0 0Fish stream 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0Aquatic invertebrates pond 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0Aquatic invertebrates stream 0 0 0 0 NE NE 0 0 NE NE 0 0 0 0 0 0 0 0

Shading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 1 BROM = Bromacil; CHLOR = Chlorsulfuron; FLUR = Fluridone; IMAZ = Imazapic; OVER = (Diflufenzopyr + dicamba) Overdrive®; SULFM = Sulfometuron methyl; and TEBU = Tebuthiuron.2 Typ = Typical application rate; and Max = Maximum application rate.3 Risk categories: 0 = No risk (majority of RQs < most conservative LOC for non Special Status species); L = Low risk (majority of RQs 1-10x most conservative LOC for non Special 

Status species); M = Moderate risk (majority of RQs 10-100x most conservative LOC for non Special Status species); H = High risk (majority of RQs >100 most conservative LOC for non Special Status species); and NE = Not evaluated. 

The risk category is based on the risk level of the majority of risk quotients observed in any of the scenarios for a given exposure group and receptor type. See the risk tables in Chapter 4 of the Ecological Risk Assessments (ENSR 2005b-k) to determine the specific scenarios that result in the displayed level of risk for a given receptor group.

Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis
 98

Table 3-15. FS-Evaluated

Herbicide Risk

Categories for

Wildlife, Fish, and

Aquatic

Species

2,4-D Dicamba Clopyralid Glyphosate2 Hexazinone Imazapyr Metsulfuron Methyl Picloram3 Triclopyr4

Application Scenario Typ5 Max1 Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ MaxAcute/Accidental ExposuresDirect spray, small mammal, 1st order absorption 06 L 0 O 0 0 0 0 0 0 0 0 0 0 0 0 L

M

Direct spray, small animal, 100% absorption

L

M

L

M

L

L

L

M

L

L 0 L 0 L

L

L

L

M

Direct spray, bee, 100% absorption

L

L NE NE 0 0 L

M

L

L 0 L 0 0 0 L

L

M

Consumption of contaminated fruit, small mammal

L

L 0 L 0 0 0 L 0 0 0 0 0 0 0 0 0 0

Consumption of contaminated grass, large mammal

M

M

L

M 0 L

L

M

L

L 0 L 0 L

L

M

L

M

Consumption of contaminated grass, large bird

L

L

L

M 0 0 L

L

L

L 0 L 0 0 0 0 L

M

Consumption of contaminated water, small mammal, spill

L

L 0 L 0 0 0 L 0 0 0 0 0 0 0 0 0 L

Consumption of contaminated water, small mammal, stream 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Consumption of contaminated insects, small mammal

M

H

L

M

L

L

L

M

L

L 0 L 0 L

L

M

L

M

Consumption of contaminated insects, small bird

L

M

L

M 0 0 L

M

L

L

L

L 0 0 0 0 L

M

Consumption of contaminated small mammal, predatory mammal

M

M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 L

Consumption of contaminated small mammal, predatory bird 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Consumption of contaminated fish, predatory bird, spill 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Fish (susceptible species) – accidental spill

H

H 0 L

L

L

H

H

L

L

M

H 0 L

H

H L/H M/H

Fish (tolerant species) – accidental spill

M

M 0 0 0 0 H

H 0 L 0 L 0 0 L

L NE/NE NE/NE

Fish (susceptible species) – acute exposure, peak EEC

M

M 0 0 0 0 M

M 0 0 0 0 0 0 L

L 0/M 0/H

Fish (tolerant species) – acute exposure, peak EEC 0 0 0 0 0 0 L

M 0 0 0 0 0 0 0 0 NE/NE NE/NE

Vegetation Treatments Using Herbicides on BLM Lands in Oregon
99

Aquatic Invertebrates – accidental spill

L

M

L

M

L

M

M

H

L

L 0 L 0 0 L

M L/M H/H

Aquatic Invertebrates – acute exposure, peak EEC 0 0 0 0 0 0 L

L 0 0 0 0 0 0 0 0 0/L 0/M

Chronic ExposuresConsumption of contaminated vegetation, small mammal, on- site 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Consumption of contaminated vegetation, small mammal, off- site 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Consumption of contaminated vegetation, large mammal, on- site

L

L 0 0 0 0 0 L

L

M 0 0 0 0 0 0 L

M

Consumption of contaminated vegetation, large mammal, off -site 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 LConsumption of contaminated vegetation, large bird, on-site 0 0 0 0 0 L 0 L 0 0 0 0 0 0 0 L

L

M

Consumption of contaminated vegetation, large bird, off-site 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Consumption of contaminated water, small mammal 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Consumption of contaminated fish, predatory bird 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Fish – chronic exposure 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0/0 0/0Aquatic invertebrates – chronic exposure 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0/0 0/0Shading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 1 The 2,4-D Risk Assessment used a maximum rate of 4 lbs/acre. However, at the National level, BLM is limited to 1.9 lbs/acre.2 Risk levels for the more toxic glyphosate formulation are presented here.3 Susceptible and tolerant aquatic invertebrates were evaluated for picloram. Information is presented for susceptible aquatic invertebrates. 4 Fist value is for triclopyr acid formulation (TEA) and second value is for triclopyr butoxythel formulation (BEE).5 Typ = typical application rate; and Max = maximum application rate.6 Risk categories: 0 = No risk (HQ < LOC); L = Low risk (HQ = 1 to 10 x LOC); M = Moderate risk (HQ = 10 to 100 x LOC); H = High risk (HQ > 100 LOC); and NE = Not evaluated. Risk categories are 

based on upper estimates of hazard quotients and the BLM LOCs of 0.1 for acute scenarios and 1.0 for chronic scenarios. The reader should consult the text of this section of the individual Forest Service Risk Assessments to evaluate risks at central estimates of hazard quotients. 

Fish susceptible species include coldwater fish, such as trout, salmon, and Federally Listed species. Fish tolerant species include warm water fish, such as fathead minnows.

Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis
 100

Table 3-16. BLM-Evaluated

Herbicide Risk

Categories for

Workers

Receptor Diflufenzopyr Diquat Fluridone Imazapic Sulfometuron Methyl Typ1 Max Accid Typ Max Accid Typ Max Accid2 Typ Max Accid Typ Max Accid

Plane - pilot NE3 NE NE

L

M

H 0 0 L-H 0 0 NE 0 0 NE

Plane - mixer/loader NE NE NE

M

H

H 0 L L-H 0 0 NE 0 0 NE

Helicopter - pilot NE NE NE

L

M

H 0 0 L-H 0 0 NE 0 0 NE

Helicopter - mixer/loader NE NE NE

M

H

H 0 L L-H 0 0 NE 0 0 NE

Human/backpack - applicator/mixer/loader 0 0 NE

L

M

H 0 0 L-H 0 0 NE 0 0 NE

Human/horseback - applicator 0 0 NE

L

L

H 0 0 L-H 0 0 NE 0 0 NE

Human/horseback - mixer/loader 0 0 NE 0 L

H 0 0 L-H 0 0 NE 0 0 NE

Human/horseback - applicator/mixer/loader 0 0 NE

L

M

H 0 0 L-H 0 0 NE 0 0 NE

ATV - applicator4 0 0 NE 0 L

H 0 0 L-H 0 0 NE 0 0 NE

ATV - mixer/loader 0 0 NE 0 L

H 0 0 L-H 0 0 NE 0 0 NE

ATV - applicator/mixer/loader 0 0 NE 0 L

H 0 0 L-H 0 0 NE 0 0 NE

Truck - applicator4 0 0 NE 0 M

H 0 0 L-H 0 0 NE 0 0 NE

Truck - mixer/loader 0 0 NE 0 L

H 0 0 L-H 0 0 NE 0 0 NE

Truck - applicator/mixer/loader 0 0 NE 0 M

H 0 0 L-H 0 0 NE 0 0 NE

Boat - applicator NE NE NE 0 0 H 0 0 L-H NE NE NE NE NE NEBoat - mixer/loader NE NE NE 0 0 H 0 0 L-H NE NE NE NE NE NEBoat - applicator/mixer/loader NE NE NE 0 0 H 0 0 L-H NE NE NE NE NE NEShading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 1 Typ = Typical application rate; Max = Maximum application rate; and Accid = Accidental rate. Typical and maximum application rate categories include short-, intermediate-, 

and long-term exposures. Accidental scenario category includes accidents with herbicide mixed at both the typical and maximum application rates and with a concentrated herbicide.

2 For all worker receptors accidentally exposed to fluridone, there is low risk from exposure to solutions mixed with water to the typical application rate, moderate risk from 

exposure to solutions mixed with water to the maximum application rate, and high risk from exposure to concentrated solutions (prior to mixing with water).

3 Risk categories: 0 = No risk (majority of ARIs > 1); L = Low risk (majority of ARIs >1 but < 0.1); M = Moderate risk (majority of ARIs > 0.1 but < 0.01); H = High risk 

(majority of ARIs < 0.01); and NE = Not evaluated. The reported risk category represents the typical/most common risk level for estimated risks from various time periods. See the Vegetation Treatments Programmatic EIS Human Health Risk Assessment Final Report (ENSR 2005l) for the range of risk levels for each scenario. 4 ATV and Truck categories include spot and boom/broadcast application scenarios.

Vegetation Treatments Using Herbicides on BLM Lands in Oregon
101

Table 3-17. BLM-Evaluated

Herbicide Risk

Categories for the Public

Receptor Diflufenzopyr Diquat Fluridone Imazapic Sulfometuron Methyl Typ1 Max Accid Typ Max Accid Typ Max Accid Typ Max Accid Typ Max Accid

Hiker/hunter (adult) 02 0 0 0 L

L 0 0 0 NE NE NE NE NE NE

Berry picker (child) 0 0 0 0 L

L 0 0 L NE NE NE NE NE NE

Berry picker (adult) 0 0 0 0 L

L 0 0 0 NE NE NE NE NE NE

Angler (adult) 0 0 0 0 L

L 0 0 0 NE NE NE NE NE NE

Residential – contaminated water (child) 0 0 0 L

L

M 0 0 L NE NE NE NE NE NE

Residential – contaminated water (adult) 0 0 0 0 L

M 0 0 L NE NE NE NE NE NE

Native American (child) 0 0 0 0 L

L 0 0 0 0 0 0 0 0 0

Native American (adult) 0 0 0 0 L

L 0 0 0 0 0 0 0 0 0

Swimmer (child) 0 0 0 0 0 L 0 0 0 0 0 0 0 0 0Swimmer (adult) 0 0 0 0 0 L 0 0 0 0 0 0 0 0 0Shading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 1 Typ = Typical application rate; Max = Maximum application rate; and Accid = Accidental rate. Typical and maximum application rate categories include short-, intermediate-, 

and long-term exposures. Accidental scenario category includes accidents with herbicide mixed at both the typical and maximum application rates and with a concentrated herbicide.

2 Risk categories: 0 = No risk (majority of ARIs > 1); L = Low risk (majority of ARIs >1 but < 0.1); M = Moderate risk (majority of ARIs > 0.1 but < 0.01); H = High risk (majority 

of ARIs < 0.01); and NE = Not evaluated. The reported risk category represents the typical/most common risk level for estimated risks from various time periods. See the Vegetation Treatments Programmatic EIS Human Health Risk Assessment Final Report (ENSR 2005l) for the range of risk levels for each scenario.

Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis
 102

Table 3-18. FS-Evaluated

Herbicide Risk

Categories for

Workers

Treatment Method

Risk Categories

2,4-D1 Dicamba Chlorsulfuron Clopyralid Glyphosate Hexazinone Imazapyr Metsulfuron Methyl Picloram Triclopyr1

Typ2 Max4 Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max

General ExposuresDirected foliar and spot treatments (backpack)

L3 M 0 0 0 0 0 0 0 0 0 L 0 0 0 0 0 0 0 L

Broadcast ground spray (boom spray)

L

M 0 L 0 L 0 0 0 0 0 L 0 0 0 0 0 0 0 L

Aerial applications (pilots and mixer/loaders)

L

M 0 0 0 0 0 0 0 0 0 L 0 0 0 0 0 0 0 L

Accidental/Incidental ExposuresWearing contaminated gloves, 1 minute

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Wearing contaminated gloves, 1 hour

M

M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 L

Spill on hands 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Spill on lower legs 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Shading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 1 Where different formulations exist, risks reported are the most conservative.2 Typ = Typical application rate; and Max = Maximum application rate.3 Risk categories: 0 = No risk (majority of HQs < 1); L = Low risk (majority of HQs >1 but < 10); M = Moderate risk (majority of HQs > 10 but < 100); H = High risk (majority of 

HQs > 100); and NE = Not evaluated. Risk categories are based on central HQ estimates. To determine risk for lower or upper HQ estimates, see the individual herbicide Risk Assessments (SERA 2005b). Risk categories are based on comparison to the HQ of 1 for typical and maximum application rates. 

4 The 2,4-D Risk Assessment used a maximum rate of 4 lbs/acre. However, at the National level, BLM is limited to 1.9 lbs/acre.

Vegetation Treatments Using Herbicides on BLM Lands in Oregon
103

Table 3-19. FS-Evaluated

Herbicide Risk

Categories for the Public

Treatment Method

Hazard Quotient

2,4-D1 Dicamba Chlorsulfuron Clopyralid Glyphosate Hexazinone Imazapyr Metsulfuron Picloram Triclopyr1

Typ2 Max4 Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max Typ Max

Acute/Accidental ExposuresDirect spray - child, entire body 03 L 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 LDirect spray - woman, lower legs 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 L

M

Dermal - contaminated vegetation, woman 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 L

L

Consumption of contaminated fruit 0 L 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 LConsumption of contaminated water - pond, spill

M

M 0 L 0 0 0 0 0 L 0 0 0 0 0 0 0 L 0 L

Consumption of contaminated water - stream, ambient

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Consumption of contaminated fish - general public

0 L 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Consumption of contaminated fish - subsistence populations

L

L 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Chronic/Longer-term ExposuresConsumption of contaminated fruit 0 L 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Consumption of contaminated water 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Consumption of contaminated fish - general public

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Consumption of contaminated fish - subsistence populations

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Shading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 1 Where different formulations exist, risks reported are the most conservative.2 Typ = Typical application rate; and Max = Maximum application rate.3 Risk categories: 0 = No risk (majority of HQs < 1); L = Low risk (majority of HQs >1 but < 10); M = Moderate risk (majority of HQs > 10 but < 100); H = High risk (majority of HQs > 

100); and NE = Not evaluated. Risk categories are based on central HQ estimates. To determine risk for lower or upper HQ estimates, see the individual herbicide Risk Assessments (SERA 2005b). Risk categories are based on comparison to the HQ of 1 for typical and maximum application rates. 4 The 2,4-D Risk Assessment used a maximum rate of 4 lbs/acre. However, at the National level, BLM is limited to 1.9 lbs/acre.

Final Environmental Impact Statement, Chapter 3: Background and Assumptions for Effects Analysis
 104

Table 3-20. BLM 1991-Evaluated Herbicide High Risk Scenarios for Workers

Treatment Method

Bromacil Diuron Tebuthiuron

Typ1 Max Accid Typ Max Accid Typ Max Accid

Aerial pilot R,C2 S,R,C NA S,R S,R NA R S,R NA

Aerial mixer-loader S,R,C S,R,C NA S,R S,R NA R S,R NA

Aerial fuel truck operator 0 0 NA 0 S,R NA 0 S NA

Backpack applicator 0 S,R NA S S,R NA 0 S,R NA

Ground mechanical 

applicator 0 S,R NA S S,R NA 0 S,R NA

Ground mechanical mixerloader 0 S,R NA S S,R NA 0 S,R NA

Ground mechanical 

applicator/mixer-loader 0 S,R NA S S,R NA 0 S,R NA

Hand applicator 0 S,R NA S S,R NA R S,R NA

Skin spill, concentrate NA NA S,R,C NA NA S,R NA NA 0

Skin spill, mixture NA NA S,R,C NA NA S,R NA NA S,R

Direct spray, person NA NA S,R NA NA S,R NA NA S,R

Shading denotes herbicides that are limited by PEIS Mitigation Measures to typical application rates where feasible. 

1

 Typ = Typical application rate; Max = Maximum application rate; and Accid = Accidental application.

2

 Risk categories: 0 = No risk; S = Systemic risk; R = Reproductive risk; C = Cancer risk; and NA = Not applicable. Marked scenarios are 

those that result in high risk under the given herbicide. High risks are defined as those exposures that may result in a margin of safety 

(MOS) < 100 or a cancer risk greater than one-in-one million. The MOS is the NOEL divided by the dose; therefore, the larger the 

MOS, the smaller the estimated human dose compared to the animal NOEL, and the lower the presumed risk to human health.

In the earlier BLM EISs, risk estimates were presented separately for different land uses (rangeland, public domain forestland, oil and gas 

sites, rights-of-way, and recreation and cultural sites). In this table, the scenario is marked if any of these land uses showed a high risk for 

the specific herbicide.

Table 3-21. BLM 1991-Evaluated Herbicide High Risk Scenarios for the Public

Treatment Method Bromacil Diuron Tebuthiuron

Accidental Application

Direct spray, person S,R S,R,C S,R

Drinking directly sprayed water 0 S,R,C R

Eating fish from directly sprayed water S,R S,R,C 0

Immediate reentry, hiker 0 S,C 0

Immediate reentry, picker S,R S,R,C S,R

Eating directly sprayed berries S,R S,R,C S,R

Angler 0 C 0

Nearby resident 0 C 0

Drinking water contaminated by a jettison of mixture S,R S,R,C S,R

Drinking water contaminated by a truck spill S,R S,R,C S,R

Risk categories: 0 = No risk; S = Systemic; R = Reproductive; C = Cancer; and NA = Not applicable. Marked scenarios are those that 

result in high risk under the given herbicide. High risks are defined as those exposures that may result in a margin of safety (MOS) < 

100 or a cancer risk greater than one-in-one million. The MOS is the NOEL divided by the dose; therefore, the larger the MOS, the 

smaller the estimated human dose compared to the animal NOEL, and the lower the presumed risk to human health.

In the earlier BLM EISs, risk estimates were presented separately for different land uses (rangeland, public domain forestland, oil and 

gas sites, rights-of-way, and recreation and cultural sites). In this table, the scenario is marked if any of these land uses showed a high 

risk for the specific herbicide.
105

Chapter 4

Changes Between Draft and Final EIS

The following changes were made to Chapter 4 between the Draft and Final EIS. Minor corrections, 

explanations, and edits are not included in this list.

Changes were made to:

• Update ecological and human health risks for triclopyr, hexazinone, and 2,4-D based on Risk Assessments 

new since development of the PEIS, and make resultant updates to the acres-by-risk table in the Human 

Health and Safety section;

• Correct certain ecological and human health risks for dicamba to reflect findings of the Forest Service Risk 

Assessment. The risk ratings in the Draft EIS were based on a BLM Risk Assessment that considered 

dicamba in combination with diflufenzopyr;

• Add additional subjects in the Incomplete and Unavailable Information section;

• Add specific discussions about Changes in Herbicide Use on Adjacent Non-BLM Lands Resulting 

From the BLM Alternatives, Cumulative Effects of Insect Spraying, and Previous Herbicide Use to the 

Cumulative Impacts section early in the chapter;

• Move the description of some of the ongoing registration actions from the Cumulative Impacts section in 

this chapter to the Non-BLM Actions Potentially Affecting the Use of Herbicides on BLM Lands in Oregon 

section in Chapter 1;

• Change “Alternative 1” to “Reference Analysis” because there is no longer an Alternative 1;

• Add information about potential effects to collectable mushrooms;

• Add information about the risks to plants of using ALS-inhibiting herbicides;

• Add recent information about the effects of herbicide treatments on the slowing of Sudden Oak Death;

• Add an Effects of the Alternatives on Climate Change: Greenhouse Gas Emissions and Carbon Storage

section;

• Add information about wind-erodible soils and provide a map;

• Add information in the Water Resources and Fish sections about State water sampling programs and 

results;

• Add recent research on the potential effects of the adjuvant POEA on amphibians, fish, and human health;

• Clarify that much of the administrative site and rights-of-way herbicide use on BLM lands is along State 

highways and county roads, and would be applied by those agencies;

• Move the Conflicts with Other Plans section to Chapter 1; and,

• Make edits in response to numerous public comments received about the Draft EIS.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 106

Table of Contents

Chapter 4 - Affected Environment and Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Incomplete and Unavailable Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Accidental Spill or Misapplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Cumulative Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Changes in Herbicide Use on Adjacent Non-BLM Lands Resulting From 

the BLM Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Cumulative Effects of Insect Spraying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Oregon Department of Agriculture’s Pesticide Use Reporting System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Forest Service’s Invasive Plant Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Previous Herbicide Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Environmental Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Current Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Biomes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Sagebrush Steppe Biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Eastern Forest Biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

East Side Riparian Biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Siskiyou Biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Western Forest Biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

Willamette Valley Biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

Noxious Weeds and Other Invasive Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Traits of Invasive Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Mechanisms of Invasion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Weed Infestations in Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

Noxious Weed Spread Rate by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

Native and Other Non-Invasive Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Susceptibility of Plant Communities to Damage from Invasive Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Endangered, Threatened, and other Special Status Plant Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

Endangered, Threatened, and other Special Status Plant Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Pests and Diseases (Sudden Oak Death) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

Sudden Oak Death Characteristics and Dispersal Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Regulations and Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

Treatment History in Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Effects (to Vegetation) by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

Air Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

107

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

Climate Trends, Projections, and Implications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

Observed Climate Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

Climate Change Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

Implications of Climate Change on Invasive Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

Effects of the Alternatives on Climate Change: Greenhouse Gas 

Emissions and Carbon Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

Soil Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

Water Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

Effects of Herbicides on Water Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

Routes for Off-Site Movement of Herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

Effect of Invasive Plants on Water Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

Wetlands and Riparian Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

Fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

Fish and Their Habitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

Setting - Aquatic Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

Effects by Alternative – Non-Special Status Fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

Effects by Alternative – Special Status Fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

Wildlife Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

Wildlife Considerations by Biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .243

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 108

Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

Livestock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

Wild Horses and Burros . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

Effects Commons to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270

Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

Fire and Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

Timber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

Existing Timber Volume Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

Invasive Plants on Timberlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282

Paleontological and Cultural Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .283

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

Paleontological Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

Cultural Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

Traditional and Cultural Uses (American Indian Interests) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286

Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290

Visual Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

Wilderness and Other Special Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

Wilderness and Wilderness Study Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

Wild, Scenic, and Recreational Rivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

National Monuments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

National Scenic and Historic Trails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

109

Areas of Critical Environmental Concern, Research Natural Areas, 

and Outstanding Natural Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

Recreation/Interpretive Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304

Recreation Management Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306

Administrative Sites, Roads, and Rights-of-Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .311

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311

Government Facilities and Roads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312

Rights-of-Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315

Social and Economic Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318

Analysis Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

Population and Demographic Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

Economic Specialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320

Perceptions, Values, and Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321

Concerns Raised During Oregon Scoping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324

Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327

Environmental Justice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

Population and Demographic Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332

Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334

Implementation Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .338

Treated Acres and Effectively Treated Acres, by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338

Costs by Treatment Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339

Total Cost and Cost per Effectively Treated Acre by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

Non-Quantified and Cumulative Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342

Human Health and Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343

Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343

Background Health Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343

Risks from Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 110

Risks from Cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344

Injury Risk from Using Herbicides and Non-Herbicide Treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344

Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345

Methodology for Assessing Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346

Effects Common to All Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347

Effects by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355

Critical Elements of the Human Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359

Other Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360

Adverse Effects Which Cannot Be Avoided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361

Relationship Between Short-Term Uses of the Human Environment and 

Maintenance of Long-term Productivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362

Irreversible or Irretrievable Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391

List of Preparers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421

Public Comment Analysis Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424

Special Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425

Distribution List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427

Elected Officials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445

Tables

Table 4-1. 2008 Oregon-Wide Use of the 18 Herbicides Analyzed in this EIS and Comparison with BLM . .

Proposed Action (Alternative 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Table 4-2. BLM Lands by Biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Table 4-3. Projected Annual Acres of Effective Noxious Weed Control by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Table 4-4. Projected Annual Noxious Weed Spread Rates and Acreage Changes for Each Alternative . . . . . . . . . . . . . . . 138

Table 4-5. Potential Vegetation Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Table 4-7. Estimated Change in Native1 Vegetation Annual Treatment Acres by Treatment Method under . . .

Alternative 4 (Proposed Action) When Compared to Alternative 2 (No Action) . . . . . . . . . . . . . . . . . . . . . . . . 154

Table 4-8. Sudden Oak Death in Oregon Forests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Table 4-9. Primary and Secondary National Ambient Air Quality Standards (NAAQS) . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Table 4-10. Non-Attainment and Air Quality Maintenance Areas in Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

Table 4-11. Mandatory Class I Areas in Oregon and Nearby in Adjoining States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Table 4-12. Emissions from Vegetation Treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

Table 4-13. Soil Order Properties and Extent on BLM Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

Table 4-14. Selected Characteristics that Affect the Fate of Herbicides in Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

Table 4-15. Miles of BLM Streams

 on ODEQ 303(d) List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

Table 4-16. Maximum Herbicide Concentration Allowed in Potable Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

Table 4-17. Herbicide Persistence in Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

Table 4-18. Drift Distance Versus Drop Diameter (NDSU 1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

Table 4-19. Glyphosate Concentration in Washington Streams 1 Hour and 24 Hours After Injection . . . . . . . . . . . . . . . . 201

Table 4-20. Herbicide Half-Life in Anaerobic Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Table 4-21. Federally Recognized American Indian Tribes with Interests in Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

111

Table 4-22. Vegetation Treatment Methods Contributing to Ground Disturbance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

Table 4-23. Estimated Annual Treatment Acres by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

Table 4-24. Approximate Acres of Noxious Weeds Currently Treated Annually in Special Areas . . . . . . . . . . . . . . . . . . . 302

Table 4-25. Approximate Acres of Other (non-noxious) Invasive Vegetation Currently Treated Annually in Special Areas 302

Table 4-26. Approximate Annual Acres of Vegetation Currently Treated Within Developed Recreation Sites .

 and Hiking Trails by Treatment Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306

Table 4-27. Population Living Below the Poverty Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330

Table 4-28. Racial and Ethnic Change Compared to the Total Population Change in Oregon, by County (1990 to 2000) . . . 335

Table 4-29. Racial and Ethnic Share of 2000 Population . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336

Table 4-30. Population Living Below the Poverty Level in Oregon, by County, Race, and Ethnicity . . . . . . . . . . . . . . . . . 337

Table 4-31. Estimated Annual Acres of Noxious/Invasive Weed Treatment by Alternative . . . . . . . . . . . . . . . . . . . . . . . . . 339

Table 4-32. Average Direct Cost of Treatment by Treatment Method, per Acre, East and West of the Cascades . . . . . . . . . . 340

Table 4-33. Annual Cost of Noxious Weed/Invasive Plant Treatment per Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340

Table 4-34. Annual Cost for Rights-of-Way/Administrative Sites/Recreation Sites Treatments. . . . . . . . . . . . . . . . . . . . . 342

Table 4-35. Leading Causes of Death by Percentage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344

Table 4-36. Estimated Annual Acres of Treatments with Risk to Worker and Public Human Health by Alternative . . . . . 356

Figures

Figure 4-1. Oregon Biomes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Figure 4-2. Relationship between Area Occupied by Invasive Species and Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Figure 4-3. Potential Vegetation Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

Figure 4-4. Soil Orders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

Figure 4-5. Wind Erosion Risk Groups 1 and 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

Figure 4-6. Source Water Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

Figure 4-7. Invasive Annual Upland Grasses East of the Cascades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

Figure 4-8. Population change for Oregon and counties east and west of the Cascades 

 (Source: US Department of Commerce 2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

113

Chapter 4

Affected Environment and 

Environmental Consequences

This Chapter presents information about those aspects of the human environment that are likely to be most 

directly affected by the management prescribed in the alternatives, and that will be used to determine which 

alternative meets the Need and best meets the Purposes described in Chapter 1. This Chapter presents the direct, 

indirect, and cumulative effects of management under the four alternatives and the Reference Analysis. The 

information presented in this Chapter forms the scientific and analytic basis for the Comparison of the Effects of 

the Alternatives section in Chapter 2. Effects described as “common to all alternatives” typically apply to the noherbicide Reference Analysis as well, unless otherwise stated.

This document is a programmatic EIS, and while many of the effects are most appropriately considered at this 

scale and all effects are described in sufficient detail to facilitate a reasoned choice from among the alternatives, 

the ability to provide specific details about some effects is necessarily limited. However, the alternatives in this 

EIS do not authorize any activities. The conduct of management activities must still comply with applicable 

environmental laws at the site-specific level, which include provision for public notice, comments, appeal, and 

consideration of site-specific resources of all kinds.

In addition to considering the potential for adverse environmental effects from herbicides, the individual resource 

sections in this Chapter examine the environmental implications of the various levels of weed control that would 

be expected to be achieved by the different alternatives. To facilitate these discussions, the Noxious Weeds and 

Other Invasive Plants, Native and Other Non-Invasive Vegetation, Pests and Diseases (Sudden Oak Death), 

Air Quality, and Climate Trend, Projections, and Implications sections are presented first, in order to quantify 

differences between the alternatives in terms of native ecosystems protected or invasive plant spread reduced. 

Incomplete and Unavailable Information

Like the PEIS, this EIS is a programmatic document that addresses the broad impacts associated with the 

Proposed Action (Alternative 4) and alternatives to the Proposed Action. Environmental impacts are assessed at 

a general level because of the broad land area analyzed in this EIS. As noted during the public scoping meeting 

in Portland on July 18, 2008 “It will be hard to evaluate non-target impacts because they usually require specifics 

about application.” Site-specific impacts will be assessed in NEPA documents prepared for district projects and 

programs by local BLM offices and tiered to this document.

The analyses of impacts of the use of herbicides in this EIS are based on the best and most recent information 

available. As is always the case when developing management direction for a wide range of resources, not all 

information that might be desired was available. The Council on Environmental Quality (CEQ) Regulations 

provide direction on how to proceed with the preparation of an EIS when information is incomplete or unavailable:

“If the information relevant to reasonably foreseeable significant adverse impacts cannot be obtained because the 

overall costs of obtaining it are exorbitant or the means to obtain it are not known, the agency shall include within 

the environmental impact statement: 1) a statement that such information is incomplete or unavailable; 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 114

2) a statement of the relevance of the incomplete or unavailable information to evaluating reasonably foreseeable 

significant adverse impacts on the human environment; 3) a summary of existing credible scientific evidence 

which is relevant to evaluating the reasonably foreseeable significant adverse impacts on the human environment; 

and 4) the agency’s evaluation of such impacts based upon theoretical approaches or research methods generally 

accepted in the scientific community.” For the purposes of this section, “reasonably foreseeable” includes 

“impacts which have catastrophic consequences, even if their probability of occurrence is low, provided that the 

analysis of the impacts is supported by credible scientific evidence, is not based on pure conjecture, and is within 

the rule of reason” (40 C.F.R. 1502.22 b). 

Addressing this last point first, it is understood that many prudent individuals view herbicides, either 

individually or in combination with other chemicals already added to the environment, as having a potential 

for the aforementioned “catastrophic consequences.” To address this concern, the BLM and Forest Service 

have supplemented the EPA herbicide registration information with over 8,000 pages of Environmental and 

Human Health Risk Assessments (Appendix 8). Risk assessments sort through the credible research to deal 

with uncertainty in interpretation and extrapolation of data. Risk assessments determine for a set of assumptions 

whether there is a basis for asserting that a particular adverse effect is possible. Prediction of potential toxic 

effects from single or synergistic exposure to herbicides and their adjuvants, inerts, and degradates, natural 

and synthesized, necessarily involves incomplete and unavailable information regarding the complexity and 

unpredictability of potential multiple exposures1. To address these uncertainties, the Risk Assessments use the 

most conservative observed response and then apply uncertainty factors at each step. The combination (product) 

of these uncertainty factors can be in the tens of thousands in cases where test results were sparse or uncertain; 

the factors applied at each step depend on the level of confidence at that step that the results will apply to the full 

range of potentially affected individuals. Additionally, the BLM added a factor of ten when applying Ecological 

Risk Assessment results to Federally Listed and other Special Status species, since they are by definition more 

susceptible because adverse effects are likely to be more significant. The results of the Risk Assessments have 

been quantified into low, moderate, and high risk categories representing the likelihood of adverse effects if the 

tested scenario is experienced (e.g., direct spray). However, the likelihood of experiencing an adverse effect 

predicted by the low, moderate, and high risk categories may be tens to thousands of times less for the average 

individual because of the uncertainty factors applied, even if the tested scenario is experienced. 

Risk assessments test or model a range of plausible scenarios including spills and direct applications on non-target 

organisms, but exposure beyond those modeled is possible. A by-the-book aerial application of sulfometuron 

methyl was done on a 20,000-acre three-month old wildfire area in south-central Idaho in November 2001. 

Winter rains were expected to carry the herbicide into the soil where it would prevent cheatgrass from overtaking 

returning native plants. An unusual combination of dry weather and strong winds carried herbicide-treated 

ash and soil onto adjacent farmlands, severely damaging thousands of acres of the following years’ crops. 

Herbicides killing non-target plants would be the most common unplanned effect, herbicides are designed to kill 

plants. Adverse effects to other organisms is less likely, but not impossible. The EPA’s sulfometuron methyl 

Reregistration Eligibility Decision (RED) published in 2008 includes application constraints designed specifically 

to avoid a repeat of the Idaho incident (see the Non-BLM Actions Potentially Affecting the Use of Herbicides on 

BLM Lands in Oregon section in Chapter 1). Standard Operating Procedures also prohibit applying sulfometuron 

methyl aerially.

For other types of environmental effects, the primary results of unavailable information is the inability to quantify 

certain impacts. Where quantification was not possible, impacts have been described in qualitative terms. A 

summary of existing credible scientific evidence that is relevant to evaluating the reasonably foreseeable adverse 

impacts on the human and socioeconomic environment (and support the BLM’s evaluation of such impacts) 

1 See Appendix 13 for a discussion of uncertainty in the risk assessment process.
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

115

has been included in this Chapter, in Chapter 3, in the PEIS (Appendix 1 of this EIS), in other appendices that 

accompany this EIS, and in supporting documents that were prepared for the PEIS that have been included 

on the BLM website at http://www.blm.gov and on the EIS project website at http://www.blm.gov/or/plans/

vegtreatmentseis/. 

Knowledge is, and always will be, incomplete regarding many aspects of terrestrial and aquatic species, 

forestlands, rangelands, the economy, and society. However, central ecological relationships are well established, 

and a substantial amount of credible information about ecosystems in the project area is known. The alternatives 

were evaluated using the best available information. While additional information may add precision to estimates 

or better specify relationships, new or additional information is unlikely to significantly change the understanding 

of the relationships that form the basis of the effects analysis presented in this Chapter. 

Locations of future projects are largely unknown, as they will be determined later. For this EIS analysis, acreage 

estimates have been separated between west and east of the Cascades, because the type of vegetation, the spread 

of invasive weeds, and the likelihood of working near water is substantially different between these two general 

areas of the State. Beyond that, local site-specific land use plans and activity plans will identify the priorities for 

each district. 

One resource for which information is incomplete or unavailable is social and economic costs of invasive 

and noxious weeds. These costs are only now being understood and quantified by economists and vegetation 

scientists at local and regional scales. Related to this problem is the uncertainty in projecting invasive weed 

spread. As noted in the Noxious Weeds and Other Invasive Plants section, individual species could have, in 

retrospect, been eradicated or reduced to one or two percent of ultimate acreages within watersheds or other 

locally defined areas, if they had been controlled when populations were only a few plants or acres. Expecting 

identification of many such opportunities is reasonable; many small populations are spreading now because 

the effective treatments are currently not available. Estimating the ecological value of such control efforts is 

also possible at the species and small watershed scale. However, the translation of these opportunities to an 

overall description of long-term vegetation changes for each alternative and a resultant ecological gain for each 

alternative is necessarily qualitative. The Noxious Weeds and Other Invasive Plants section later in this chapter 

address this point further, noting that the estimates of weed spread rate for the different alternatives involves many 

assumptions, and thus the projected differences in infested acres after 15 years should be viewed not so much as 

predictions of what would occur over time, but as reasonable approximations of the relative differences between 

the alternatives. 

As noted in the Air Quality section, the science is lacking to develop a complete carbon budget principally due 

to the lack of information on belowground carbon dynamics in all ecosystems and very limited information on 

aboveground carbon dynamics in rangeland ecosystems. Although information to more thoroughly analyze 

carbon is unavailable, one of the known qualitative trade-offs are that activities that can restore healthy 

functioning ecosystems, including treatments to reduce invasive plants, tend to increase carbon sequestration. The 

analysis points out that the Proposed Action (Alternative 4)’s replacement of roadside mowing with herbicide use 

should decrease fossil fuel use. These factors point to the Proposed Action having favorable effects on climate 

change and long-term air quality when compared to the No Action Alternative (Alternative 2), but the difference 

is qualitative and likely so small as to play little role in influencing the choice between the alternatives.

Herbicide use rates on immediately adjacent non-BLM lands are unknown, and therefore cumulative effects at 

the small watershed scale are impossible to quantify. However, statewide herbicide use levels described in the 

Cumulative Impacts section in this Chapter indicate the proposed BLM use would be less than one percent of all 

use in the State (on 25 percent of the State’s area). This, and the application of Standard Operating Procedures 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 116

and PEIS Mitigation Measures, the proposed application methods, and the expected size and distribution of the 

treatment sites, indicates little if any contribution to cumulative off-site effects even at small geographic scales. In 

fact, the control of invasive plants on BLM lands has the potential to reduce herbicide use on adjacent non-BLM 

lands (see Cumulative Impacts section in this Chapter).

Finally, the analysis does not describe the implications of eliminating individual herbicides within Alternative 3 

with respect to future weed spread. Table A9-2 provides information about which herbicide effectively controls 

which target plant, and several of the potential target plants are readily susceptible to only one herbicide. Beyond 

this, the implications of losing a single herbicide are discussed more qualitatively. For example, the EIS notes 

that having additional herbicides increases the opportunity to select one that will meet the vegetation control 

objectives while minimizing adverse effects at that particular treatment site. The removal of the sulfonylureas 

would increase the pounds of alternative herbicides needed. The EIS could have attempted to identify the highpriority control species and then analyzed, individually, the implications of excluding certain herbicides from 

Alternative 3. The EIS did not attempt such an analysis in part because: a) priorities will likely change over 

the 15-year life of the EIS; b) there is no complete inventory of all invasive plant populations so priorities and 

emphasis might change with additional information; c) the needs and priorities of the Oregon Department of 

Agriculture, cooperators, and adjacent landowners will vary by geographic area and time; and d) the estimate of 

future noxious weed spread rate under Alternative 3 is too gross to reveal the implications of loss of individual 

herbicides. On this last point, the Appendix 12 discussion of 2,4-D estimates the removal of 2,4-D from 

Alternative 3 would change the weed spread rate prediction from seven percent per year to more than eight 

percent, because 2,4-D is so effective, either singly or as a part of tank mixes, on so many weeds. This estimate 

is possible because of the experience and projected uses of 2,4-D. No specific estimate is attempted for the other 

herbicides for the reasons stated above. 

Accidental Spill or Misapplication

Spills happen when valves fail, when vehicles or handheld equipment tips over or falls into water bodies, when 

applicators forget herbicides are present in equipment, and so forth. Standard Operating Procedures, job hazard 

analyses or risk management assessments, safety and handling plans, designated travel routes, mixing rules, 

separated equipment, and other processes are designed to minimize spill occurrence, but the alternatives propose 

to treat thousands of acres in an area where there are thousands of streams and lakes present. Many of the 

invasive plants are in the riparian zones or even in water, so some amount of herbicide mix gets near water. 

The Fish, Wildlife Resources, Native and Other Non-Invasive Vegetation, and Water Resources sections address 

spill scenarios that represent worst-case potential impacts to a pond and to a stream2. The scenarios, addressed in 

the Ecological Risk Assessments (see Appendix 8), are a truck and a helicopter spilling entire loads (200-gallon 

spill and 140-gallon spill, respectively) of herbicide mixed for the maximum application rate into a 1⁄4 acre, 

1-meter-deep pond, and into a small but perennial fish-bearing stream. The pond scenario is the one discussed in 

the PEIS Vol. II:C-22, and analysis in that volume examines the pond concentration against the Risk Assessments’ 

toxicity endpoints for the fish, aquatic invertebrates, and non-target aquatic plants. For that analysis, the 

concentration of herbicide in the pond water is based on the concentration in the spilled solution, the volume 

spilled, and the volume of the pond assuming instantaneous mixing.

Spills directly onto soil would likely have fewer adverse effects than spills into water. Under this situation, the 

site would be assessed for a connection to ground or surface water and the soil isolated or removed. This type of 

remedial action is generally conducted by an environmental services crew contracted for such work or in connection 

with the State of Oregon Department of Environmental Quality’s (ODEQ) Emergency Response Program.

2 Risk Assessments do not evaluate stream spills because the herbicide concentrations would be dependent on flow rate 

and the distance from the spill. Spills lethal in ponds would be expected to be lethal in streams for some distance.
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

117

Spilling the contents of an application tank or helicopter load is the largest event reasonably foreseeable without 

being speculative. The potential impacts of larger spills have not been estimated. Although a larger event is 

possible, the variables of which herbicide, how much, and where, become speculative when focused to individual 

resources. Effects of a spill of normally transported and mixed quantities could vary from slight to significant 

depending upon these variables. Larger spills could include barrels of product (up to 55 gallons) dropped, 

ruptured, punctured, or even lost, with effects similar to spilling 400 gallons of mix. Herbicides could be 

deposited in waterways by a vehicle accident at a stream or river crossing, or by a mixing/drafting error although 

Standard Operating Procedures require mixing and loading operations to be done in areas where an accidental 

spill would not contaminate an aquatic body. Spill plans are required for all herbicide projects, are on site during 

operations, and include requirements that responsible local and State agencies are immediately notified. Clean up, 

mitigation, and site rehabilitation is required.

In addition to the possibility of spills, there is a possibility of accidental application contrary to the prescription 

or the label. Increasing the number of herbicides will, at least in the short term, result in field offices using 

herbicides that are less familiar to them, leading to errors or to non-label applications, and unexpectedly damaging 

non-target plants. However, the availability of more target-specific herbicides, effective in lower quantities, 

would more likely have the opposite effect, that of reducing average pounds per acre applied and reducing less 

effective and repeated applications that attempt to control weeds for which the currently available four herbicides 

are less effective. Site-specific planning and the use of certified applicators should limit non-label applications. 

Uncertainties including spills and accidental applications are discussed in the Risk Assessments for each herbicide 

(Appendix 8), and the risk levels for such events are included on risk tables applicable to the specific resource sections.

Cumulative Impacts

Cumulative impacts to the environment are defined in the CEQ regulations as those that result from the 

incremental effects of a proposed action when added to other past, present, and reasonably foreseeable future 

actions, regardless of which agency or person undertakes them (40 C.F.R. 1508.7). In general, the effects of past 

actions are considered in Affected Environment discussions for each resource section. In each resource section 

in this Chapter, the various types of direct and potentially cumulative effects are identified by considering the 

following possible sources of effects for each resource and for this EIS as a whole:

1. The Proposed Action;

2. Existing actions (already doing some of the same thing);

3. Past actions (effects previously imparted by other actions);

4. Other present actions (other things going on in the effects area);

5. Reasonably foreseeable actions; and,

6. Mitigation of adverse effects that cannot be avoided with the selected alternative. 

These types of effects are not necessarily separated or labeled in each resource section in this Chapter. Because 

this is a statewide programmatic document covering the estimated level of future herbicide use in Oregon (that 

will be subsequently covered by district or project site-specific analysis), this entire analysis is itself a cumulative 

effects analysis. 

Past, present, and reasonably foreseeable future actions that are not directly related to the alternatives but that 

potentially bear on the effects of the alternatives presented in this EIS are described here:
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 118

Changes in Herbicide Use on Adjacent Non-BLM Lands Resulting From the BLM 

Alternatives

Adjacent private landowner values and uses would benefit from improved invasive weed control on BLM lands 

because weed spread onto adjacent non-BLM lands would be reduced if overall weed spread on BLM lands were 

reduced. In addition, weed control would be more efficient for private owners and BLM managers combined, 

because additional herbicides would make cooperative, cross-boundary treatments more feasible. It would seem 

to follow, then, that one effect could be reduced herbicide use on adjacent BLM lands. Such a reduction could 

be significant in places like Malheur County where BLM lands make up more than 70 percent of the landscape, 

and in the checkerboard O&C lands west of the Cascades. The effects analysis for Alternatives 4 and 5 in the 

Timber section suggests such benefits would occur even for right-of-way treatments in checkerboard lands under 

Alternative 4 (Proposed Action). 

Cumulative Effects of Insect Spraying

In 2009, APHIS and/or the Oregon Department of Agriculture sprayed insecticides on 34,000 acres of BLM 

lands for the control of grasshoppers. This spraying has been an annual event; the treated area varies in size 

and area from year to year. There is also a potential to spray for Mormon crickets, although no acres were 

treated for this insect in 2009. Most insecticide treatments on BLM lands in Oregon are likely to be spatially or 

temporally separated from most herbicide treatments proposed in this EIS, so virtually few organisms except, 

conceivably, plants, would be expected to have active doses of both materials at the same time. Any overlaps of 

concern should be identified in site-specific analyses; ongoing noxious weed treatments would be a consideration 

during insecticide spray planning in part because of the widespread use of noxious weed biological controls. 

Cumulative adverse effects to humans or other elements of the environment are most likely when two pesticides 

share a common mechanism of toxicity. That is, they both affect an organism the same way. Cumulative effects 

assessments conducted by the EPA typically begin by grouping pesticides by mechanism of toxicity (EPA 2002). 

Because insecticides and herbicides work so differently, even a concurrent application would be unlikely to result 

in significant additive environmental effects when both products are applied within label limits. Synergism is not 

impossible however; the 2,4-D Risk Assessment reports that 2,4-D induced cytochrome P450 (a natural animal 

enzyme that processes toxins) in the southern armyworm (Spodoptera eridania) caused synergistic effects on 

insecticide toxicity (Kao et al. 1995). In addition, exposure to 2,4-D caused decreased carbaryl and permethrin 

insecticide toxicity. 

Oregon Department of Agriculture’s Pesticide Use Reporting System

In July 2009, the Oregon Department of Agriculture published an annual report compiling the second full year of 

reporting under Oregon’s Pesticide Use Reporting System. For non-household use pesticides, Oregon State law 

requires self-reporting. There were many problems identified in this reporting system, including:

• many (if not most) businesses and commercial users3 didn’t realize that they were required to report their 

pesticide use;

• there was difficulty correctly identifying the pesticide used;

• funding didn’t allow the Oregon Department of Agriculture to follow up on every report; and,

• people were not familiar with the online reporting system, had varying computer skills, or had no 

online access.

3 Includes all uses except household use.
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

119

These errors could have caused overestimates or underestimates in the final reported numbers. In addition, these 

estimates do not include pesticides used in households4, a possibly significant figure. However, applicators filed 

nearly 343,000 reports of pesticide use totaling 19,696,784 pounds of pesticides including fungicides, herbicides, 

insecticides, rodenticides, and others. This is 645 times the pounds of herbicides the BLM would apply under the 

Proposed Action (Alternative 4).

Twenty percent of this total was the soil fumigant metam-sodium, with most of that being applied to the farmlands 

along the Columbia River in the northern part of the State east of the Cascades. The herbicide glyphosate (the active 

ingredient in Roundup®) was reported at 1,914,143 pounds of active ingredient (ODA 2009b), or more than 957,000 

acres if the typical rate5 is assumed. Table 4-1 shows the reported pounds in Oregon for herbicides included in this 

EIS. Included are their numerical rank in the Oregon report in terms of pounds applied (if they were in the 100 

most-used pesticides), and equivalent acres calculated from the BLM typical application rate and, for comparison 

purposes, the estimated acres of the same herbicide expected to be applied by the BLM under the Proposed Action 

(Alternative 4) and its percent of the 2008 Oregon total. (The BLM manages about 25 percent of the lands in 

Oregon.) Agricultural uses are included in the Oregon totals; the table does not attempt to compare like uses.

4 The report includes a household component. 1,717 households in Oregon agreed to track their pesticide use over the 

course of the year. Response and reporting consistency was poor, and the the Oregon Department of Agriculture did not 

extrapolate that information out to make any general conclusions about household pesticide use. 

5 Typical application rates for each herbicide are shown on Table 3-4.

Table 4-1. 2008 Oregon-Wide Use of the 18 Herbicides Analyzed in this EIS and Comparison with BLM

Proposed Action (Alternative 4)

Herbicide and rank1

Lbs Reported by the 

Oregon Department 

of Agriculture

Assumed Acres 

Statewide2

Estimated Acres 

under Alt 4 

(Proposed Action) on 

BLM Lands

% of OR acres that 

BLM Proposed 

Usage Would 

Represent

2. Glyphosate 1,914,144 957,072 4,000 0.42%

7. 2,4-D 778,878 778,878 5,400 0.69%

13. Diuron 385,174 64,196 1400 2.18%

25. Triclopyr 125,542 125,542 4,100 3.27%

31. Hexazinone 105,284 52,642 300 0.28%

34. Dicamba 96,964 323,213 1,600 0.50%

50. Clopyralid 48,592 138,834 2,300 1.66%

59. Imazapyr 29,859 66,353 2,600 3.92%

83. Sulfometuron methyl 16,866 120,471 1,000 0.83%

99. Bromacil 11,189 2,797 900 32.18%

Picloram 5,891 16,831 3,000 20.37%

Metsulfuron methyl 5,252 175,067 2,900 1.66%

Diquat 2,334 2,334 0 0.00%

Chlorsulfuron 2,006 42,681 4,100 9.61%

Tebuthiuron 720 1,440 300 20.82%

Imazapic 314 10,032 14,000 139.68%

Fluridone 22 147 300 209.79%

Diflufenzopyr + Dicamba No data No Data 0 0% 1

 Rank is only known for the herbicides included in Oregon Department of Agriculture’s list of 100 most used Pesticides 2

 Reported pounds divided by the BLM typical application rate.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 120

Forest Service’s Invasive Plant Program

The Forest Service manages about 22 percent (14.5 million acres) of the land in Oregon. The Forest Service’s 

Invasive Plant Program proposes to treat approximately 29,058 acres with herbicides in Oregon and Washington 

annually to control invasive plants. Herbicides available for use by the Forest Service include chlorsulfuron, 

clopyralid, glyphosate, imazapic, imazapyr, metsulfuron methyl, picloram, sulfometuron methyl, and triclopyr, 

all of which are analyzed in this EIS, and sethoxydim. The Region 6 (Forest Service in Oregon and Washington) 

Invasive Plant Program’s EIS was finished in 2005 (USDA 2005a) and the Record of Decision was signed 

October 2005 (USDA 2005b). Individual National Forests are in the process of completing site-specific analyses 

tiered to that decision. 

Previous Herbicide Use

Past herbicide use by the BLM will contribute little to cumulative herbicide effects. The BLM has been limited 

by the 1984/87 court injunction to only spraying noxious weeds with four herbicides. This means most treatments 

have been spot treatments, not broadcast sprays. The four herbicides themselves are all moderately persistent in 

water, and not persistent (2,4-D) to persistent (picloram) in soils, which means that all of them would have broken 

down somewhere between ten days to a year after application. These herbicides have been applied in such a 

way as to avoid effects to non-target species. Herbicides on BLM lands are not generally reapplied in the same 

location year after year, as policy does not allow repeated treatments with a method that has been shown to be 

ineffective (USDI 1992b).

Being limited to four herbicides has contributed to the spread of invasive plants because of restrictions and/

or limitations on the plants that can be controlled and the places that they can be used. Limiting the number of 

herbicides can also contribute to some invasive plants becoming resistant to certain herbicides. These issues are 

discussed in the Noxious Weeds and Other Invasive Plants section. 

Environmental Setting

The BLM manages about 15.7 million acres in Oregon, or about 25 percent of the lands in the State. About 2.3 

million of these acres lay west of the Cascades, about 2.1 million of which was assigned to the BLM by the O&C 

Act of 1937 to be managed primarily for sustained timber production. These lands are also managed for wildlife 

habitat, recreation, and so forth (see Background in Chapter 1).

Most BLM lands east of the Cascades more closely resemble BLM lands in other western states, and include dry 

forest and sagebrush steppe of the high desert. These lands are managed for a variety of uses including habitat, 

watershed protection, recreation, livestock grazing, and oil, gas, and mineral development. Information about 

these other uses, as well as about special lands designations, is presented in resource sections in this Chapter.

Current Climate6

A discussion of the current climate and weather patterns in Oregon is important to the understanding of the broad 

vegetative communities (or biomes) within the State; how invasive plant trends might affect that vegetation; and, 

how expected climate change might affect invasive plant trends and thus affect the need for changes in management.

6 General sources for this section include Taylor and Hatton (1999), OCS (2009), and WRCC (2009). 
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

121

The Pacific Ocean exerts a strong influence on the climate across Oregon, with a stronger influence west of the 

Cascades than on the eastern side. This maritime influence moderates winter minimum and summer maximum 

temperatures. The abundant moisture incorporated into the air masses that move across the Pacific is largely 

responsible for the abundant rainfall over western Oregon and at higher elevations of the eastern portion of the 

State. The occurrence of extreme low or high temperatures is generally associated with the occasional incursion 

of continental air masses.

A series of mountain ranges affect precipitation amounts across the State. The Coast Range runs north-south 

down the full length of the State; the Cascade Range runs north-south from the Columbia River to within 50-75 

miles of the California border; and, the Blue Mountains run northeast-southwest from the Snake River to the John 

Day and Deschutes Rivers. Other mountain ranges include the Siskiyou Mountains in southwest Oregon, and 

the Steens Mountain in southeast Oregon. The mountain ranges generally increase in elevation from west to east 

and from north to south. As a result, moisture entering the State from the Pacific Ocean is progressively removed 

from the air masses as they rise, cool, and condense to cross the various ranges. Precipitation amounts are highest 

along the coast and lowest in the rain shadow of the Steens.

A maritime climate characterizes the coast and northwestern part of the State. This area has very mild winters and 

the coolest summers in the State. Temperatures have the least diurnal and annual variation along the coast. High 

temperatures rarely exceed 90° F and low temperatures rarely drop below 0° F, with average winter minimums 

mostly above 32° F. August is usually the warmest month and January the coldest month. Precipitation averages 

100-200 inches on the coast, 30-60 inches in the Willamette Valley and 80-120 inches on the western slopes of 

the Cascades. Most precipitation falls in November through March, as rain below 1300 feet elevation and snow 

above 4900 feet elevation. The 1300-4900 foot elevation band is known as the transient snow zone with winter 

precipitation falling as a mix of rain and snow. The coast is frequently cloudy or foggy throughout the year while 

clouds and fog are much less common in summer in northwest Oregon. Thunderstorms are rare, peak in May and 

are usually wet. The Columbia River pierces both the Coast and Cascade ranges, allowing some of the maritime 

influence to reach northeastern Oregon, with the influence stronger in winter than in summer.

The more complex terrain of the Siskiyou Mountains results in less influence from the marine air, even though 

the Rogue and other rivers flow into the Pacific Ocean. As these rivers cross through the coastal part of the 

mountains, the river valleys narrow considerably, limiting the ability of the marine air to penetrate inland in 

summer. Because of this (coupled with its lower latitude), southwest Oregon has a Mediterranean-type climate. 

Summers in southwest Oregon are among the warmest in the State, although winter temperatures are generally 

mild. High temperatures commonly exceed 90° F in summer while low temperatures rarely drop below 0° F, 

although the average minimum temperature is below 32° F. July is usually the warmest month and January the 

coldest month. Precipitation amounts and timing are similar to that of northwest Oregon, although generally on 

the low end of the range. Most winter precipitation falls as rain below 1300 feet elevation and snow above 4900 

feet elevation and a mixture in the transient snow zone. Winters tend to be cloudy and summers quite sunny. 

Thunderstorms occur 12-18 times per year, peaking in August with many storms between mid-July and midSeptember producing little rain (dry thunderstorms).

Eastern Oregon has a more continental climate similar to that of the northern Rocky Mountains in the north and 

the Great Basin in the south. The Blue Mountains limit the penetration of marine air into the southeastern part 

of the State at all times of the year. Eastern Oregon is generally higher in elevation than western Oregon, which 

tends to moderate summer temperatures somewhat but results in cold winters. Eastern Oregon has the highest 

diurnal and annual temperature variation in the State. High temperatures in summer commonly exceed 90° F 

and low winter temperatures often drop below 0° F with average minimum temperatures generally well below 

32° F. July is the warmest month in north-central and southeast Oregon while August is generally the warmest 
 122

Vegetation Treatments Using Herbicides on BLM Lands in Oregon

month in south-central and northeast Oregon. January is the coldest month. Average annual precipitation ranges 

from 5 to 30 inches with higher amounts in the higher elevations of the Steens and Blue Mountains. Most winter 

precipitation falls as snow above 4900 feet, rain below 1300 feet, and a mix of rain and snow in between. Overall, 

eastern Oregon has more sunny days throughout the year than western Oregon. Summer thunderstorms occur 12-

18 times per year, peaking in August. Storms between mid-July and mid-September tend to be dry.

Oregon is subject to a variety of severe weather events that help set the ecological limits for various native and 

non-native plants. Among these are cold snaps, heat waves, and drought. Cold snaps tend to occur when arctic 

air moves west of the Rocky Mountains and into eastern Oregon with occasional events reaching as far as the 

Oregon coast. A cold snap occurs over a several day period, often with both daily maximum and minimum 

temperatures dropping through the period. Twenty major cold snaps have occurred in the State between 1898 and 

1999. Cold snaps may affect only a small portion of the State or the entire State. January is the most common 

month for cold snaps, followed by December and early February.

Heat waves occur when most or all of the State lies under strong high pressure that brings descending warming 

air and clear skies resulting in temperatures well above average for the time period affected. Occasional very 

hot days tend to be more common than multi-day (two or more days) heat waves in western Oregon. Thirty-five 

multi-day heat waves have been documented between 1898 and 1999. In eastern Oregon, the hottest temperatures 

during heat waves typically occur in river valleys. Heat waves have occurred in every month except January, but 

the hottest temperatures and longest heat waves typically occur in June through August.

Drought is difficult to define with much precision; identifying the beginning and end of a drought is even more 

difficult. Most commonly, drought is defined relative to its duration and impacts on agriculture or hydrology, or 

for regulatory purposes. This analysis uses hydrological, or meteorological, drought. The hydrological definition 

includes multiple time scales (seasonal, annual, and multi-year) and all aspects of water supply (precipitation, 

stream flow, groundwater, and so forth). All of Oregon is subject to seasonal drought in summer, normally 

a very dry period with high inter-annual variation in precipitation amounts across the State. For ecological 

considerations, most plant and animal species can readily survive a one-year, or annual, drought.

Multi-year droughts can alter many ecosystem processes and lead to various changes in plant and animal 

communities. Since winter and spring precipitation dominate Oregon’s climate, below-average precipitation 

in these months has a much greater impact than below average precipitation in summer and fall. The Palmer 

Drought Severity Index, which incorporates precipitation, runoff, evaporation, and soil moisture, is the most 

widely used indicator of hydrological drought. The Index7 indicates five significant multi-year droughts have 

affected all or part of Oregon since 1900. The worst drought remains the 1928-1941 period, the Dust Bowl era, 

which affected the entire State. Eastern Oregon was affected by severe drought from 1959 to 1964 while western 

Oregon was affected from 1976 through 1981. Another statewide drought occurred from 1985 through 1994. A 

third statewide drought began in 1999 and likely ended in 2005 in western Oregon but apparently has not ended in 

eastern Oregon.

Two very important drivers of Oregon’s climate, particularly in winter and spring are the El Niño-Southern 

Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) (Mote et al. 2004). The cycle for ENSO is 2-7 

years and for PDO is 20-30 years. While ENSO primarily affects ocean conditions in the equatorial Pacific, PDO 

affects ocean conditions in the central and northern Pacific. Together, these two phenomena affect the strength 

7 The Palmer Drought Severity Index has numerous shortcomings in large part due to its inability to handle snow 

adequately. It remains the most widely used indicator in large part due to the length of record. The Standardized 

Precipitation Index addresses many of the shortcomings of the Palmer index and is becoming more widely used, but the 

period of record is short, as it has only been used since 1993. 
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

123

and location of the Aleutian Low in winter and subsequent storm tracks. When both ENSO and PDO are in the 

same phase (cool-cool or warm-warm), the effects on Oregon’s climate are magnified; when both are in opposite 

phases (cool-warm or warm-cool) the effects are somewhat cancelled. During the warm phase of either, the 

Aleutian Low tends to deepen and cause the storm track to split around the Pacific Northwest, resulting in warm, 

dry winters. However, a moderate strength El Niño event is more likely to lead to that outcome. A strong El Niño 

event also causes the Aleutian Low to shift eastward, bringing warm, wet winters to Oregon. The wettest winters 

with the highest snowpack tend to occur when both ENSO and PDO are in their cool phases.

Biomes

Because biophysical and biological characteristics vary widely on BLM lands in Oregon, it is helpful to divide 

the analysis area into smaller, more homogeneous areas for analysis. The PEIS to which this EIS tiers uses 

ecoregions adapted from Bailey (1998, 2002) to delineate areas with similar climatic conditions, geomorphology, 

and soils. These factors influence the composition and functioning of vegetative communities, and thus such 

regions can be expected to have sufficiently consistent responses in susceptibility and effects of invasive plants 

and vegetation treatments to facilitate effects presentations.

For analysis in this Oregon-specific EIS, six biomes are identified in part by subdividing ecoregions used in the 

PEIS, and in part tiering to physiographic provinces used in the 1994 Northwest Forest Plan applicable primarily to 

lands near to or west of the Cascades. Five of the biomes are shown in Figure 4-1; the sixth is the East Side Riparian 

Biome, consisting of the riparian habitat that closely follows perennial and in some cases, intermittent streams in the 

dry eastern part of the State. The biomes provide a context for describing other elements of the affected environment 

later in this Chapter. However, these biomes are combined and/or split as needed to appropriately describe resource 

effects in this Chapter. Table 4-2 shows the amount of land managed by the BLM by biome.

The composition and distribution of plant communities in Oregon has been influenced by many factors, including 

climate, drought, fire, browsing by wildlife, domestic livestock grazing, settlement, mining, development, and 

cultivation. Other activities that have a direct or indirect effect on plant communities include logging, recreational 

activities, and development of rights-of-way including road construction and maintenance. In addition, 

competition with non-native invasive plant species has resulted in the loss of native plant communities. Climate 

trends, projections, and implications are discussed later in this Chapter.

Table 4-2. BLM Lands by Biome

Biomes Acres of BLM Land % of Total BLM Land

West of the Cascades 2,334,000 15

Western Forest 1,482,600 9

Willamette Valley 19,100 less than 1

Siskiyou 832,200 5

East of the Cascades 13,377,400 85

Eastern Forest 1,150,700 7

Sagebrush Steppe 11,618,500 74

East Side Riparian 608,200 4
 124

Figure 4-1. 

O

regon

Biomes

Vegetation Treatments Using Herbicides on BLM Lands in Oregon
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

125

Sagebrush Steppe Biome

Description and trend - Plant communities occurring in this region are adapted to dry summers and cold winters. 

Elevations range between 2,500 and 8,000 feet. Precipitation ranges between eight and sixteen inches and 

occurs primarily during the winter. Three major sagebrush plant communities are generally identified: Wyoming 

big sage, mountain big sage, and low sage. An assortment of shrub species is associated with each sagebrush 

community, and understory vegetation throughout the type is typically dominated by a mixture of perennial bunch 

grasses such as bluebunch wheatgrass, and forbs. These plant communities are both relatively resistant to, and 

adapted to, low intensity wildland fire, generally having a mean fire return interval of 20 to 100 years depending 

on climate and site productivity (Miller et al. 2000, Wright and Bailey 1982). In any event, recent unnaturally 

high-intensity wildfires (caused at least in part by invasive annual grasses like cheatgrass) have substantially 

reduced or removed sagebrush and its seed from burned areas, although most other shrub and understory species 

in a healthy sagebrush steppe community will reseed or resprout after fire.

Native sagebrush plant communities benefit watersheds by providing vegetative litter, which serves as a nutrient 

source, provides soil surface protection by reducing impacts of precipitation, and traps surface water allowing 

for percolation into the soil profile. Healthy plant communities discourage encroachment of invasive plants. 

However, healthy sagebrush steppe communities are rapidly disappearing due to invasion of non-native plants 

(especially cheatgrass), high-intensity wildfires, and encroachment of western juniper, and other disturbances. 

Sagebrush communities have been identified as one of the most threatened land types in North America, and as 

much as half of this land type has already been lost in the Great Basin (SageSTEP 2009).

The onset of settlement of western lands in the late 1800s and introduction of livestock grazing on public land 

through the early 1930s, combined with fire suppression, has greatly affected the native plant communities in 

eastern Oregon (Miller and Wigand 1994). Largely unmanaged grazing during this time and the introduction of 

non-native plant species resulted in declines of native perennial grass species and establishment of competitive 

(and often invasive) grasses. Invasive annual grasses have a competitive advantage because of their ability to 

utilize limited moisture early in the growing season, and because of their short life spans culminating in prolific 

seed production. Their rapid growth and short life spans also result in the production of fine flammable fuels that 

contribute to an increase in the spread and intensity of wildfires. Repeated wildfires result in the loss of sagebrush 

over large areas, leaving these areas dominated by invasive annual grasses. This conversion results in the loss 

of sagebrush obligate species, leading to an overall loss of species’ diversity. Roughly five million acres of the 

Sagebrush Steppe and Eastern Forest biomes are estimated to be occupied by invasive annual grasses (Figure 4-7).

Prior to European settlement, native western juniper were primarily confined to rocky ridges or surfaces with 

sparse vegetation (Barney and Frischknecht 1974). The suppression of periodic fire has helped contribute to a 

four-fold expansion of western juniper since 1930 into 6.4 million acres in eastern Oregon (Thompson 2007). 

Western juniper’s high water usage and allelopathic effects completely eliminate native perennial grass, shrubs 

and forbs, and even ponderosa pine, and create a challenging environment in which to restore native plant 

communities (Miller et al. 2005). The elimination of native plants by encroaching western juniper results in 

increased erosion and decreased soil available for plants to reestablish. An estimated five million acres in eastern 

Oregon are currently occupied (Miller et al. 2005) with an unnaturally high population of western juniper.

Land ownership patterns - In the southern two-thirds of this biome, the BLM is the predominant landowner. 

Intermingled private lands are dominated by agriculture, ranching, and their associated communities. Adjacent 

ranchers often hold permits to graze livestock on BLM lands, and grazing-related infrastructure developments are 

often on BLM lands under permit. Boundaries between private and public lands are often discernable by no more 

than a fence, if at all, and vegetation migrates readily between ownerships. Successful invasive weed control 

and other vegetation management is typically a cooperative effort between private owners, weed control districts, 

weed boards, local governments, and the BLM.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Eastern Forest Biome

Plant communities occurring in this region are adapted to dry summers and cold winters. Elevation is between 

2,500 and 8,000 feet. Precipitation ranges between 10-27 inches and occurs primarily during the winter (Franklin 

and Dyrness 1988). Plant communities are dominated by various species of coniferous trees, with ponderosa pine 

in the lower elevations and western larch and grand fir in the higher elevations. Lodgepole pine is also present, 

particularly close to the Cascades between Highway 97 and the crest. A mixture of perennial bunch grasses 

and forbs is the most common associated vegetation. This associated vegetation also often includes sagebrush, 

bitterbrush, and various other shrubs, particularly under the more open ponderosa stands and between forested 

sites. Low flat areas often associated with water can be dominated by perennial grass/forb communities, and most 

of these are private lands dating from early homesteading. Variation in plant communities at the local scale is 

influenced by differences in soil types, moisture regimes, weather patterns, cold air drainage pockets that preclude 

successful conifer regeneration, and grazing and fire history.

Frequent natural fires historically kept the pine stands open, regenerated the lodgepole pine before it began to 

naturally decline about age 80, and kept the fir restricted to higher elevations. Recent decades of fire suppression 

coupled with harvesting of larger pines have resulted in higher-than-normal stocking that includes dense 

understories, drought-susceptible fir, and the buildup of downed logs and limbs. This denser forest shades out 

the shrub/forb/grass understory vegetation and otherwise changes the structure and composition of the plant 

community and its dependent wildlife. The accumulation of biomass and understory fuel ladders result in 

frequent stand replacing wildfires. These unnaturally intense fires kill most trees regardless of size, setting back 

succession and allowing invasive plants to get a foothold. Nearly 100 percent of east side pine forests have 

invasive annual grasses in the understories (Donnegan et al. 2008), but they do not materially affect the relatively 

fire resistant pines and other conifer species.

Forest management activities are conducted to promote forest stand health and resiliency to fire, insects, and 

disease. Treatments include thinning to reduce densely canopied young forests, fuels reductions of overstocked 

stands resulting from many years of fire suppression, fire salvage to reduce fuels and capture surplus mortality, 

and/or uneven age stand management to restore pre-settlement stand conditions. During 2005 -2007, an average 

of 2.3 million board feet (MMBF) of timber was offered for harvest each year, and an average of 2.0 MMBF was 

harvested (2,450 acres per year).

East Side Riparian Biome

Riparian-wetland areas occupy approximately 4 percent of public land acres in eastern Oregon, but contain some 

of the most productive and highly prized resources in this part of the State. The functions of wetland and riparian 

areas include water purification, stream shading, buffering effects of flooding, stream bank stabilization, ground 

water recharge, and habitat for aquatic, semi-aquatic, and terrestrial plants and animals (EPA 2005b). Riparian zones 

include the green zones along flowing water features such as rivers, streams, and creeks (Gebhardt et al. 2005) and 

many standing water features such as lakes, ponds, and seeps. Ephemeral streams where water flows for only brief 

periods during storm runoff events typically do not support a full suite of riparian vegetation or benefits.

Species present include but are not limited to cottonwoods, aspen, and other Populus species (often genetically 

distinct by drainage), alder, willows, dogwood, water birch, conifers, and their associated shrubs, forbs and 

grasses (although some riparian areas are characterized by grass and forb communities)(Crowe et al. 2004). This 

vegetation is immediately associated with the stream channel and associated wetlands, and typically contrasts 

starkly with the surrounding upland vegetation.
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127

The BLM defines Proper Functioning Condition (PFC) for wetland and riparian areas to be functional when 

adequate vegetation, landform, or large woody debris is present (Prichard et al. 1993): 

1) to support adequate vegetation, landform, or debris to dissipate energies associated with wind action, 

wave action, and overland flow from adjacent sites thereby reducing erosion and improving water quality; 

2) filter sediment and aid floodplain developments; 

3) improve floodwater retention and groundwater recharge; 

4) develop root masses that stabilize islands and shoreline features against cutting actions; 

5) restrict water percolation; 

6) develop diverse ponding characteristics to provide the habitat and the water depth, duration and 

temperature necessary for fish production, water bird breeding, and other uses; and, 

7) support greater biodiversity 

PFC assessment does not take into consideration the habitat value of the area for fish and wildlife.

The BLM in eastern Oregon administers 8,508 miles (467,840 acres) of riparian areas of which 38 percent is at 

PFC; less than 34 percent is functioning at risk; 2 percent is non-functional, and 26 percent is unknown. There are 

also 140,328 acres of wetland of which 93 percent is at PFC and the balance is unsurveyed (USDI 2007b).

Siskiyou Biome

Geography and Physical Environment - The Siskiyou biome encompasses the physically and biologically 

diverse Klamath Mountains in southwest Oregon. The terrain is highly dissected with elevation ranging from 

less than 1,000 feet in valley bottoms to 4,000 to 6,000 feet on ridge crests, with some peaks as high as 8,000 

feet. The region generally experiences mild wet winters with long dry hot summers, commonly referred to as 

a Mediterranean climate. The biological diversity is attributed to the varying annual precipitation amounts, 

elevation ranges, topography, the type of parent material or underlying soils, and soil moisture (Strothmann and 

Roy 1984).

Vegetation communities can be separated into three main forest types: oak woodlands and savannah, mixed 

conifer/evergreen forest, and coastal forest (Agee 1993). Oak woodlands, savannahs, and shrublands typically 

occupy drier sites at lower elevations. Grass-dominated8 savannahs may have up to 30 percent canopy cover of 

trees. Mesic (moist) oak woodlands may show greater canopy closure of California black oak or Pacific madrone, 

while drier non-clay sites show increased domination by shrubs. Common tree species include oaks (mostly black 

and white oak), Pacific madrone, and conifers (predominantly ponderosa pine and some Douglas-fir and cedars). 

The shrub layer consists of buckbrush, birch-leaf mountain-mahogany, manzanita, and poison oak.

Mixed conifer/evergreen forests in this biome typically include an overstory of mixed conifers, with conifers 

and sclerophyllous9 broadleaved trees in the under-story. The most dominate species is Douglas-fir. Depending 

on the elevation, topography, and annual precipitation, other dominant or co-dominant species could include 

tanoak, ponderosa pine, sugar pine, and Pacific madrone. A variety of other trees may also be present including 

hardwoods (such as canyon live oak, black oak, and chinquapin) and conifers (such as incense-cedar in the lower 

elevations, Jeffrey pine on serpentine, western hemlock, grand fir and white fir in mid to upper elevations, PortOrford-cedar and Pacific yew on moist or coastal sites and within riparian areas, and knobcone pine on recent 

burns). Understory communities (low shrub and herb layers) are usually not well developed but can include 

poison oak, Oregon grape, California honeysuckle, vine maple, oceanspray, California hazel, and wildrose 

(Strothmann and Roy 1984). Riparian areas are similar but with an increase in hardwoods such as big leaf maple 

8 Most commonly Roemer’s fescue and/or Idaho fescue.

9 Hard-leaved evergreen shrubs that are adapted to the hot summer.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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and dogwood. After stand-replacing fires, succession to conifers can be slow, often going through evergreen 

hardwood or dense evergreen chaparral stages first (Strothmann and Roy 1984).

The coastal forest lies in a thin band along the coast. Mature forests are co-dominated by Sitka Spruce, western 

hemlock, and western redcedar (Agee 1993). Douglas-fir, true fire, and Port-Orford-cedar are found as secondary 

species, while red alder may dominate disturbed sites, and black cottonwood and big leaf maple can be found in 

riparian areas (Agee 1993). The understory may include salmonberry, salal, red huckleberry, and vine maple. 

Slightly more inland and on the lower drier valleys, Douglas-fir is the climax species while Pacific Silver fir 

and western hemlock occur in the higher elevations. The coastal forest shares many density and structural 

characteristics with the Western Forest Biome further north, but coastal forests in the Siskiyou Biome include 

Port-Orford-cedar, tanoak, and a few redwood.

Disturbance trends - At most sites away from the coast, frequent low and mixed severity natural and 

anthropogenic (American Indian) fires historically played a critical role in determining species’ composition and 

structure (Agee 1993). Low intensity fires in the oak woodlands, savannahs, and mixed-conifer forest controlled 

regeneration of fire-intolerant species, promoted fire-tolerant species, maintained an open forest structure, reduced 

forest biomass, decreased density-related insect and disease mortality, and helped maintain habitats for species 

that utilize open stand structure (Graham et al. 2004). Fires affected soil properties, watershed hydrology, and 

forest stand dynamics. Oak woodlands, savannahs, and the lower elevation drier mixed-conifer forests were 

burned frequently by American Indians (Agee 1993) much more so than lightning. These fires were of low 

intensity and usually of short durations, carried by surface layer fuels such as grasses, forbs, leaves and needles, 

maintaining open prairies and savannahs, and reducing the understory vegetation and surface fuels.

In the oak woodlands, savannahs, and mixed-conifer forest, intensive fire suppression efforts in the last 60 years 

has resulted in considerable fuel accumulation in some areas, and substantial shifts in tree species’ composition 

and forest stand structure. This shift has led to increasing the density of shrubs and oaks thereby transforming the 

savanna into woodlands, and has resulted in an expansion of Douglas-fir and shrubs in the oak woodlands (Agee 

1993). Fire exclusion in the drier mixed conifer forest has contributed to an increase in understory vegetation, 

permitting vast areas to accumulate uncharacteristically high levels of ladder fuels, which contribute to an 

increased risk of high-severity, stand replacement fire (Graham et al. 2004). As a result, these changes have made 

forests more susceptible to large, high-severity fires such as the 2002 Biscuit Fire, which burned over 500,000 

acres of forest.

In the more moist coastal and higher elevation forests, fire was less frequent but typically burned at higher 

intensity resulting in a high-severity fire regime and larger fires (Agee 1993, Frost and Sweeney 2000). These 

fires also resulted in patch diversity, but at a much larger scale than patches occurring in the low and mixed fire 

severity landscapes. These natural forest patches contributed to the diversity of the broader landscape (USDA, 

USDI 2007:149). Less frequent high-severity fires occurred in the forest adjacent to the coastal forests and in 

some rare cases during periods of prolonged drought in the Sitka Spruce coastal forest (Agee 1993). Wind events 

historically played a greater role in the Sitka Spruce coastal forest in creating forest openings and regeneration 

(Agee 1993).

Land ownership and use - Land ownership patterns as well as public and commercial use in this biome 

substantially contribute to the risk of invasive plant spread. At higher elevations and in some areas nearer the 

coast, large sections of continuous public lands occur on National Forests. However, at lower elevations much 

of the land is a fragmented checkerboard pattern of lands managed by the BLM, State of Oregon, private timber 

companies, other private owners, and tribes. Home building and other development has increased urbanization 

of oak woodlands, savannahs, and lower elevation mixed conifer-forest into what is commonly referred to as 

the wildland urban interface. This urbanization and appurtenant increase in wildland use has increased wildfire 

occurrence and off-highway vehicle and other recreational use, all of which contribute to the introduction and 

spread of invasive plants.
Final Environmental Impact Statement, Chapter 4: Affected Environmental and Environmental Consequences

129

Western Forest Biome

Geography and Physical Environment - The Western Forest Biome is dominated by the coast range that 

reaches 4097 ft in elevation, and the lower elevations on the west slope of the Cascades (where BLM lands are 

generally below 4,000 ft.) Both mountain ranges are north-south trending, generally separated north of Eugene 

by the Willamette Valley (Figure 4-1). Geologic conditions in the coast range are highly variable, but typically 

comprised of older basalt and newer marine sedimentary formations.

Most of the biome is rugged with steep canyons. Precipitation and temperature interact with physiography to 

provide the setting for hydrologic processes and disturbance events. Tributary streams are short with steep 

gradients. The Willamette River drains the northeastern half of the biome. The remainder is drained by rivers 

flowing directly to the Pacific (Umpqua, Nestuca, etc.). Streamflow peaks are generally caused by winter rainfall 

and from spring snowmelt.

Vegetation - Abundant precipitation and mild temperatures allow highly productive coniferous and deciduous 

forests to dominate. Complex, multi-storied evergreen forests occupy much of the region, with species’ 

composition varying by altitude and climate. At lower elevations, Douglas-fir, western hemlock, western red 

cedar, grand fir, Pacific silver fir, and Sitka spruce are the dominant conifer tree species. In the Coast Range, 

Sitka spruce dominates the immediate coast, while a mosaic of Douglas-fir, western hemlock and western red 

cedar dominate inland areas. Douglas-fir plantations of various ages up to 50 years are common and even more 

prevalent on intermingled private lands that are intensively managed. Sitka spruce/western hemlock forests occur 

where climatic conditions are dominated by maritime influence.

Hardwood species occur sparsely throughout this type of forest and are often found in disturbed or riparian 

habitats. Hardwoods include red alder, bigleaf maple, and, on warmer drier sites, Pacific madrone and giant 

chinquapin (Franklin 1988). Understory species include salal, oceanspray, western swordfern, redwood sorrel, 

Cascade barberry, and Pacific rhododendron. Understory community composition varies with locality, but similar 

understories are found in both mature and less mature forests.

Vegetation in pre-forest succession is heterogeneous and reflects logging, fire, and other disturbance history. 

Woodland ragwort and fireweed are common herbs that are found the first years after fire or other disturbance. 

The herbaceous community is succeeded by shrubby species such as perennial vine maple, trailing blackberry, 

low Oregon grape, Pacific rhododendron, and various ceanothuses. Diversity and biomass of herbs and shrubs 

declines once the canopy closes.

Non-forested areas account for about four percent of this biome (105,000 acres), and include rock outcrops, cliffs, 

talus areas, grasslands, shrublands, herbaceous wetlands, vernal pools/ponds, bodies of open water (e.g., ponds, 

small lakes, reservoirs, and rivers), coastal dunes/open sand, coastal grasslands, and salt marshes.

Riparian and wetland areas occur throughout the biome. Red alder, willow, and other broadleaf species dominate 

floodplains and recent mass movement (slide) areas. Although riparian areas serve as important habitat for some 

wildlife species, they are not as important to most wildlife as riparian areas east of the Cascades because the 

vegetation and moisture difference from the surrounding landscape is not so pronounced. Some key ecological 

processes that shape riparian and wetland areas are tree growth and mortality (which affect stream shade, nutrient 

input, and large wood delivery), hydrology (floods and groundwater), landslides, and sediment routing. These 

factors have great influence on the ability of aquatic habitat to support fish populations (Meehan 1991, OWEB 

1999). Aquatic ecosystems in this biome are naturally dynamic, changing over time due to natural events as 

wildfires and large storms, and the subsequent floods, hillslope failures, landslides, and debris flows (Haynes et al. 

2006, Naiman et al. 1992).
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Disturbance trends – Before the 1970s, large wood was generally considered a nuisance or hazard in streams. 

Large wood was systematically removed from streams to benefit river navigation, prevent or decrease flooding 

effects, enhance log transportation, and improve fish passage (Maser and Sedell 1994 cited in Reich et al. 2003). 

In the wetter northern portion of this biome (particularly in the coast range), high-intensity stand-replacing fires 

and/or major wind events may be separated by hundreds of years. Regular small-scale events (gap dynamics) are 

caused by insects, slides and floods (evidence of historic mass movements is ubiquitous), windthrow, and disease. 

Recent timber harvest has changed the dominant vegetation, with most harvest units having been replaced with 

even-aged stands of Douglas-fir.

The primary natural disturbance event in the southern part of the biome is wildfire. Historically, frequent low or 

mixed-severity fires limited the expansion of less fire-tolerant species such as true firs. Recent exclusion of fire 

has resulted in expansion of these species into the surrounding ecosystems. The resultant overstocking has led to 

more insect mortality, and has increased fuels supporting a trend toward more intense fires (USDA 2005a; USDA, 

USDI 2007).

An extensive road network has contributed to an increase in slide events, wildfires, and the increasing soil and 

vegetation disturbance. These disturbance events, coupled with high human use, have introduced and spread 

invasive plants like Scotch broom, gorse, English ivy, and Himalayan blackberry to forestland. These non-native 

plants typically reduce native-plant diversity and prevent or delay the regeneration of native vegetation.

Land ownership and use - BLM lands here are primarily used for timber production and recreation. Land 

ownership patterns as well as public and commercial use in this biome substantially contribute to the risk of 

spreading invasive plants. At higher elevations and in some areas nearer the coast, large sections of continuous 

public lands occur on National Forests. However, at lower elevations much of the land is a fragmented 

checkerboard pattern of lands managed by the BLM, State of Oregon, private timber companies, other private 

owners, and tribes. The population centers in the nearby Willamette Valley contribute to increased wildfire 

occurrence, timber harvest, off-highway vehicle and other recreational use, and grazing, all of which contribute to 

the introduction and spread of invasive plants.

Willamette Valley Biome

Geography and Physical Environment - The Willamette Valley Biome is a lowland approximately 150 miles 

north-to-south, and 60 miles wide. Prior to European settlement, the broad, Willamette Valley was characterized 

by rolling prairies, widely-spaced fire-tolerant oak, Douglas-fir, and ponderosa pines, and extensive wetlands, 

all maintained by extensive American Indian burning. Willamette Valley landforms are terraces and floodplains, 

interlaced and surrounded by rolling hills. European settlement ended most of the burning, and Douglas-fir, 

western hemlock, and western red cedar forests encroached onto the lower hills and edges of the valley, creating 

much of the conifer forests visible today (Johannessen et al. 1971). Some oak savannah remains, but most have 

been developed for agricultural and urban uses. Oregon white oak woodlands and prairies are now remnant 

patches. Deciduous shrubland, often established following fire or other disturbance, can be found scattered 

in coniferous forest areas in small to large patches. These shrublands can persist for decades or longer before 

succeeding to woodland, then forest.

Native west side grasslands are found in dry, upland prairies and savannas or on grass- and forb-dominated 

cliffs, bluffs and balds, which often have a minor component of Oregon white oak, Douglas-fir and/or 

ponderosa pine. Moist meadows can occur in small valleys. Bunchgrasses dominate the grasslands, while a 

combination of sedges, rushes and bunchgrasses dominate natural meadowlands. Many of these have been 

invaded by non-native grasses.
131

Final Environmental Impact Statement, Chapter 4: Noxious Weeds and Other Invasive Plants

Disturbance trends - Conversion for urban and agricultural uses is the ultimate disturbance, because the site no 

longer returns to forest, prairies, or wetlands. The amount of conversion was substantial during settlement, but 

Oregon’s land-use system now limits such changes. Little remains of some of the native grassland communities. 

Farming, recreation, and other human activities along with a well-developed road system readily spread invasive 

plants in this biome.

Land ownership and use - BLM lands occupy only a small portion of this biome, generally along the hilly west, south, 

and east margins. Productive soils and a temperate climate make it the most important agricultural area in Oregon.

Noxious Weeds and Other Invasive Plants

Affected Environment

Invasive plants (or weeds) are non-native aggressive plants with the potential to cause significant damage to 

native ecosystems and/or cause significant economic losses. They successfully compete with native plants for 

light, water, soil nutrients, and space, resulting in their dominance of the plant community and the displacement 

of native plants and the fauna that depend on them. Invasive plants can cause profound changes to native 

ecosystems including changes in seral progression, habitat, nutrient cycling, water availability, soil qualities, soil 

productivity, and fire regimes. Ecological damage from extensive noxious weed infestations is often permanent 

(Dewey 1995). The spread of invasive plants threatens the structure and function of many ecosystems worldwide 

(Higgens et al. 1996, Heywood 1989:31-34). There are estimated to be over 1,030 species of non-native plants 

in Oregon (Oregon Flora Project 2008), and 225 of them are considered invasive by the BLM in Oregon. Not all 

non-native plants are considered invasive. Indeed over 90 percent of our food crops are non-native to the United 

States. There are approximately 2,000 non-native plants estimated to be in the U.S. (OTA 1993). 

Noxious weeds are a subset of invasive plants that are County, State, or Federally Listed as injurious to public 

health, agriculture, recreation, wildlife, or any public or private property. Noxious weeds are regulated by State 

and Federal laws, such as the Federal Noxious Weed Act of 1974 and the Oregon noxious weed quarantine 

administrative rule (OAR 603-052-1200). The quarantine rule prohibits import, transport, propagation, or sale 

of State listed noxious weeds and plants on the Federal Noxious Weed List (7 C.F.R. 360.200) because they are 

detrimental to agriculture, natural resources, and/or public health. These weeds choke out crops, destroy range 

and pasture lands, clog waterways, affect human and animal health, and threaten native plant communities. 

Designating additional noxious weeds is a continuous process. The number of noxious weeds listed by the State 

of Oregon increased 40 percent between 1991 and 2001.

Traits of Invasive Plants

Noxious weeds and other invasive plants have biological traits that enable them to colonize new areas and 

successfully compete with native species. While not all invasive plants share all of these traits, most have one 

or more that allow them to compete successfully. These traits include deep tap roots or extensive root systems; 

little surface foliage (allowing the plants to grow later in the summer than most native rangeland plants); earlier 

growth and reproduction than most natives; seeds that remain viable near the soil surface for decades; adaptations 

for spreading long and short distances; production of many seeds from one plant; long lifespan; ability to delay 

flowering; ability to reproduce vegetatively; tolerance for a wide range of physical conditions; rapid growth; 

self pollination; ability to compete intensively for nutrients; and production of toxic compounds that negatively 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 132

affect neighboring plants (USDA 2005a). Once established, these species can dominate due to the absence of the 

insects, pathogens, disease, and herbivores that keep them in balance in their native ecosystems.

Mechanisms of Invasion

Invasive plants can enter Oregon from other countries in shipping containers, on vehicles, on or in various 

products or packing materials, on clothing, with other plants or soil, as contaminants in seed mixes, or can be 

brought in intentionally as ornamentals or to accomplish some management objective. They also enter Oregon 

from neighboring states, and move great distances within the State on off-road and other vehicles, on camping and 

other recreational equipment, on pack stock and livestock, in hay and other feed crops, on construction equipment, 

on the wind, on animals including within feces, and as intentionally moved ornamental or medicinal plants or 

inadvertently within the soil of such plants (USDI 1996). Infestations begin mostly on disturbed sites, such as at 

trailheads, along roads and trails, firebreaks or burned areas, landing pads, oil and gas development sites, timber 

harvest areas, wildlife and/or livestock concentration areas, and campgrounds. Linear disturbances such as roads, 

pipelines, and fences can serve as corridors for weed spread. Weeds at public use sites are more likely to be 

spread to additional areas.

The plant invasion process occurs in three phases: introduction, establishment, and spread. Once an introduction 

occurs, a delay or lag phase often takes place while an invasive plant becomes established. The length of this 

initial phase varies, but it can last for up to 100 years (Hobbs and Humphries 1995). This phase is followed by a 

period of rapid growth that continues until the invasive species reaches the bounds of its new range (Figure 4-2, 

Mack et al. 2000).

Figure 4-2. Relationship between Area Occupied by Invasive Species and Time.
133

Once an invasive plant is introduced, control programs are most effective if they identify and eradicate the 

infestation while it is still in the introduction phase. Control efforts in this phase can prevent future infestations 

on tens to hundreds of times more acres (Radke and Davis 2000:25). Regular field surveys attempt to detect as 

many populations in the introduction (or early establishment) phase as possible. Once a weed is well established, 

not only is it more numerous and likely to have contributed heavily to the soil seed bank, native plants critical to 

successful restoration on control sites may have been severely reduced or eliminated. Eradication at this point 

quickly becomes impractical.

Maintaining cover of native and other non-invasive plant species on public lands is critical to halting the spread 

of noxious weeds. In a 45-year study of a sagebrush steppe landscape in Idaho, areas with the highest cover of 

native species exhibited the greatest resistance to invasion by cheatgrass (Anderson and Inouye 2001). Open and 

disturbed plant communities are more likely to be invaded, while undisturbed forests are less invaded (Rejmanek 

1989:389-390). However, shifts in plant communities resulting from climate change, whether those shifts 

occur rapidly through increases in stand-replacing wildfire or more gradually through increased mortality in the 

native ecosystem, will favor increased expansion of invasive plants (see the Climate Trends, Projections, and 

Implications section in this Chapter). Natural, climate driven, or human-caused ground-disturbances increase the 

likelihood of invasive weeds becoming established. Planned BLM management activities potentially creating 

a moderate or high risk of establishing invasive plants must include a plan for their prevention, monitoring, and 

control (Appendix 3) (USDI 1992b).

Weed Infestations in Oregon

In 2007 it was estimated that noxious weeds infest 1.2 million of the 15.7 million acres of BLM administered 

lands in Oregon, and are spreading at an annual rate of about 12 percent or 144,000 acres per year (Appendix 

7). At this rate, acres infested10 with noxious weeds will double in about eight years. As noted in the Integrated 

Vegetation Management section in Chapter 3, a full range of direct control practices with and without herbicides 

is currently being implemented on just over 20,000 acres per year, mostly targeted at infestations still in 

the introduction or early establishment phase, or on the perimeter of larger infestations, where they have a 

disproportionately beneficial effect on the long-term spread rate. Without this control, the current spread rate 

would certainly be higher. However, certain weed species cannot be effectively controlled with methods or tools 

currently available to the BLM in Oregon.

For about 25 species of noxious weeds already well established in the State, weed control in Oregon has included 

the release of bio-controls in the form of insects and pathogens from the weed’s native lands (see Table A7-1)

(OSU 2009). While these agents do not eliminate the weed, they often reduce its density enough to reduce 

ecological damage and allow native and other non-invasive plants to survive. 

There are 120 species on the Oregon noxious weed list in June 2010 (Appendix 7). Six of these are estimated to 

infest more than one million acres each statewide (all ownerships): yellow starthistle, Scotch broom, Himalayan 

blackberry, quackgrass, field bindweed, and Canada thistle. Another eight are estimated to infest more than 

100,000 acres statewide: perennial pepperweed, medusahead rye, St. Johnswort, diffuse knapweed, poison 

hemlock, English ivy, bull thistle, and tansy ragwort. Oregon loses more than $83 million annually to just 21 

noxious weeds (Radke and Davis 2000).

10 “Infested” means anything from a single individual to a monocultures of noxious weeds, so the 1.2 million acres is 

gross acres. Radke and Davis’ (2000) examination of 21 noxious weeds in Oregon (all ownerships) suggested a gross 

to net ratio of about 5:1. Adverse effects to various resources described within this Chapter usually vary by the level of 

infestation. Nevertheless, adverse effects are proportional to the acres expected to become infested under each alternative. 

Final Environmental Impact Statement, Chapter 4: Noxious Weeds and Other Invasive Plants
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 134

Additional examples include:

• Purple loosestrife is present in 32 of Oregon’s 36 counties. One mature plant can produce 2.7 million 

seeds per year the size of ground pepper. It also spreads vegetatively; disturbance to underground stems 

or roots during incomplete plant removal initiates bud growth (WA Dept of Ecology a).

• Spotted knapweed has invaded 34 of Oregon’s 36 counties. It suppresses surrounding native plants 

by altering soil chemistry, forming monocultures that have resulted in changes to elk migration routes. 

During a 12-year period ending in 2001, spotted knapweed expanded 42-fold, and yellow starthistle 

expanded 11-fold. 

• Blackberry infests many riparian areas and is beginning to occur east of the Cascades. It limits human and 

wildlife access to streams, outcompetes native riparian species, and the resultant monoculture provides 

poor soil cover and stream bank protection, resulting in increased sedimentation and damage to water 

quality and spawning gravels. 

• Scotch broom-related reductions in timber volume within Oregon have been valued at over $47 million 

annually (Radke and Davis 2000:19-20). 

• Yellow starthistle makes rangeland unusable, closing grazing allotments, ruining ranches, and displacing 

wildlife. 

• Some noxious weeds like gorse, Scotch broom, and medusahead are highly flammable. In 1936, the town 

of Bandon, Oregon, was destroyed and 11 citizens killed by a fire propagated by gorse, a highly flammable 

plant introduced 70 years earlier (Simberloff 1996). This species is still being battled along the Oregon 

and California coasts.

Other (non-noxious) invasive plants, particularly cheatgrass (Bromus tectorum) infest at least 5 million additional 

acres of BLM lands in Oregon. Cheatgrass, (like noxious medusahead rye), is an invasive annual grass that 

grows, seeds, and matures and dries early in the summer. This pattern depletes soil moisture needed by native 

plants, and results in flashy fuels that burn regularly – also eliminating native species. The seeds survive the 

burning, so the ecosystem is rapidly converted from a perennial bunchgrass/forb/shrub community relatively 

resistant to fire, to a monoculture of unpalatable11 annual grasses that burn regularly. In addition to the ecological 

damage, the fire hazard created by these grasses threatens communities and other infrastructure improvements.

See Additional Information About the Ecological Damage Caused by Invasive Plants in Appendix 7.

BLM cooperates with the Oregon Department of Agriculture, local weed boards, adjacent landowners, and others 

to control infestations. The State assigns noxious weeds to two lists depending upon statewide management 

objectives (Appendix 7: Table A7-1). A-list weeds are likely to occur in Oregon or do occur in Oregon at a low 

enough level that eradication is possible statewide. B-list weeds are more common and widespread, at least in 

some areas of Oregon. Additionally, a T-list includes weeds from either the A or B list for which the State has 

targeted funding.

Environmental Consequences

Noxious weeds and other invasive plants typically have characteristics that enhance their survival at the expense 

of native and other non-invasive species. Their structure and development is such that they use more moisture, 

provide less soil protection, alter soil chemistry, are unpalatable to wild horses and livestock, do not support 

native fauna, and have various other negative effects on the natural or current environment. In order to help 

11 to wildlife and livestock
135

quantify these effects, this section attempts to estimate the differences between the alternatives in terms of how 

well they will or will not change the rate of spread of noxious weeds on BLM lands, and thus how they will affect 

the total acres infested with noxious weeds at some point in the future. The importance of these estimates cannot 

be overstated. Although the various resource sections in this Chapter identify some additional risk to the human 

environment from the proposal to increase the number of herbicides and the management activities they may be 

used for on BLM lands in Oregon, the environmental and even human health risks associated with the continued 

increase of noxious weeds must likewise be considered.

While projections of weed spread in this section are based on considerable published data, it is acknowledged 

that attempts to quantify future weed spread require many assumptions. Some of these assumptions may not be 

entirely accurate, either because management emphasis may change or because the assumptions themselves are 

simply flawed. Therefore, the projections in this section should be viewed not so much as predictions of what will 

occur over time, but as reasonable approximations of the relative differences between the alternatives.

Efforts by academia and others to develop spread rate models for individual plants have been unsuccessful 

because of the number of variables involved and the inability to predict propagule movement by humans. 

Therefore adverse effects from individual invasive plants are described more qualitatively than quantitatively in 

this EIS. Predicting general relationships for noxious weeds as a group, however, is possible.

Noxious Weed Spread Rate by Alternative

The following estimates are for noxious weeds only. Invasive plants are not included because their spread rate 

was not part of most “current rate” spread estimates gleaned from several sources (Denton 2009), because invasive 

plant control efforts under the alternatives are expected to be devoted primarily to noxious weeds, and because 

noxious weeds are typically the most damaging environmentally and economically. There are many other invasive 

plants infesting Oregon that are also a problem on BLM lands – particularly cheatgrass. The estimates are based 

on acres projected to be treated under each of the alternatives (Table 3-3), which assume current budget trends.

Acres of Noxious Weed Control Treatments by Alternative

Table 3-3 in Chapter 3 shows the annual acres of herbicide and non-herbicide control treatments projected to 

take place under each of the EIS alternatives for the next ten to twenty years. Under the No Action Alternative 

(Alternative 2) projected (gross) treatments for the control of noxious weed and other invasive plants total 45,500 

acres (Table 4-3), of which 16,700 are expected to be done with herbicides (Table 3-3). Most or all of these 

treatments (and certainly all of the herbicide treatments) are likely to be focused on noxious weeds.

Total (gross) control acres under the Reference Analysis are estimated to be 42,100 acres, none using herbicides. 

Approximately 75 percent of the herbicide treatments under of Alternative 2 (No Action) would still be conducted, 

but with non-herbicide methods under the Reference Analysis. The remaining 20 percent would not be conducted 

because many noxious weeds are simply not effectively controlled with non-herbicide methods and because such 

methods typically cost more and all treatments are limited by budget constraints.

The increase in the number of herbicides that would be available under Alternative 3 would mean additional weed 

species could be treated effectively. Weeds currently being treated with the four herbicides under Alternative 

2 (No Action) could be treated more efficiently with additional herbicides, and some expensive non-herbicide 

treatments currently being done would be replaced by herbicide treatments. The annual acres of herbicide and 

non-herbicide invasive plant control treatments under Alternative 3 through 5 are projected to be 58,700 gross 

acres, most of which are expected to be focused on noxious weeds.12 

12 One thousand annual treatment acres using imazapic under this alternative are expected to be used on cheatgrass, which 

is an invasive plant but not a State-listed noxious weed. Numbers used in effectiveness projections discussed in this 

section are for noxious weeds only.

Final Environmental Impact Statement, Chapter 4: Noxious Weeds and Other Invasive Plants
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 136

Percent of Treatments that Result in “Effective Control”

Weed control treatments are not 100 percent effective at controlling all treated populations. Under any alternative, 

some level of retreatment may be necessary to achieve complete control. A five-acre treatment, for example, 

would be monitored, and a portion of the acres might require retreatment. The amount of retreatment necessary is 

largely a function of how likely treatments are to control the target weed on the first try.

Reference Analysis – No Herbicide Use: Two-thirds of the noxious weeds in Oregon cannot be effectively 

controlled with non-herbicide methods (Appendix 7: Table A7-1). Non-herbicide methods (particularly 

mechanical and directed livestock treatments) are also more likely to disturb soils (which leads to reinvasion) and 

can transport weeds off site. In addition, many woody species resprout if controlled with non-herbicides methods. 

The Wallowa-Whitman National Forest Invasive Plant Treatments Draft EIS (USDA 2009b:107) estimates 

efficiency of their mostly non-herbicide No Action Alternative at 25 to 35 percent. The estimated efficiency of 

the Reference Analysis in this EIS is 30 percent. In other words, weeds would be controlled on 30 percent of the 

acres treated under a no herbicides strategy.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only: The efficiency of Alternative 2 is 

limited (though not nearly as severely as the no-herbicide Reference Analysis) because only four herbicides are 

available. Sixteen of the State listed noxious weeds cannot be effectively treated under this alternative (Appendix 

7: Table A7-1). Treatments for these species do not eradicate the infestation but are often conducted anyway 

because they reduce vigor or retard seed development and thus slow the spread. The estimated efficiency of 

treatments under Alternative 2 is 60 percent of the total acres treated. In other words, weeds would be controlled 

on 60 percent of the acres treated under Alternative 2. Difficulty in conducting cooperative projects (because 

many herbicides cannot be used on BLM lands) contributed to this 60 percent. In addition, the inability to treat 

other invasive plants with herbicides increases the likelihood additional plants will become well established 

before they are declared noxious weeds.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases: Under 

Alternative 3, the wider range of herbicide options would increase the effectiveness of the average treatment. 

Although some level of retreatment would still take place, the additional herbicides would substantially 

improve the chances the weed would be controlled by a treatment. With the additional herbicides available, this 

alternative could effectively control 116 of the 120 State listed noxious weeds (Appendix 7: Table A7-1), as well 

as cheatgrass and other invasive annual grasses. Non-herbicide methods could be more focused where they are 

effective, or used in conjunction with herbicides and thus all treatments under this alternative would be more 

efficient. More effective cross-boundary cooperative projects contribute to the efficiency. Some new invasive 

plants would be identified and controlled before they are listed as noxious weeds. The estimated efficiency of this 

alternative is 80 percent.

The efficiency of the alternative translates the gross treatment acres listed on Table 3-3 to effectively treated acres

(Table 4-3). The effectively treated acres are those that control the weeds on the site and prevent future weed spread.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses and Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation 

Management Objectives: Alternatives 4 and 5 assume the same 57,700 acres of noxious weed treatments as 

Alternative 3 (and thus the same efficiency), but add 9,300 acres of herbicide use to control native and other noninvasive plants encroaching on rights-of-way, administrative sites, and recreation sites (Table 3-3). These sites 

are typically managed in an early seral or disturbed condition favorable to noxious weeds. These areas are also 

likely to become infested with noxious weeds and other invasive plants since seeds are more readily transported 

into access corridors by human activity. Thus, the 9,300 acres of herbicide treatments targeted at native and other 
137

non-invasive plants in these areas under Alternative 4 (and 5) are assumed to also (incidentally) control additional 

noxious weeds missed by noxious weed control efforts under Alternative 3.13 It is estimated 25 percent of these 

rights-of-way and related treatments, or 2,350 acres, will incidentally treat these undetected noxious weeds (Table 

4-3). This 25 percent estimate includes a de facto weed control effect from simply replacing existing mechanical 

vegetation controls with herbicide treatments, reducing the likelihood that the maintenance equipment itself will 

spread weeds down the road. It also includes the effect that having fewer noxious weeds near travel corridors and 

recreation sites reduces the likelihood of weeds being spread along and from these sites.

Alternative 5 adds two additional herbicides and 4,800 acres of additional vegetation treatments (primarily habitat 

improvement), but these are not expected to substantially increase the noxious weed control acres from those 

calculated for Alternative 4 (Proposed Action).

Effects of Early Treatments

As noted earlier, in 2007 it was estimated that noxious weeds infested 1.2 million acres of BLM lands in Oregon, 

and they are spreading at an estimated rate of 12 percent, or 144,000 acres, each year (Appendix 7). This spread 

rate is assumed to be partly a function of, or in equilibrium with, the No Action Alternative (Alternative 2) level of 

weed control treatments. Therefore, differences in the level of effective treatments between Alternative 2 and the 

other alternatives can be expected to result in changes to the 12 percent current annual rate of spread.

Alternative 3 would effectively treat 18,860 more acres each year than Alternative 2 (from Table 4-3). At a 

minimum, these acres would directly reduce the 144,000-acre annual weed spread to 125,140 acres and thus the 

spread rate to 10.5 percent. However, because BLM weed treatments under all alternatives are only a portion 

of the 144,000-acre annual weed spread, weed treatments do not target the average acres. Typical treatments 

target new species, new or small populations of existing species, and advancing edges of larger populations in 

order to keep weeds from infesting new drainages and other geographic areas (containment)14. These treatments 

effectively keep populations from moving into the establishment phase where their spread rate becomes 

exponential, and thus the treatments reduce future infested acres many times more than is represented by the 

direct acres treated. Control efforts in the introduction and early establishment phase of an invasion (Figure 4-2) 

can prevent future infestations on tens to hundreds of times more acres than are actually controlled.

13 This same 9,300 acres is treated with non-herbicide methods under the Reference Analysis and Alternatives 2 and 3, 

but mowing and other general non-herbicide right-of-way maintenance treatments would not be expected to remove 

noxious weeds completely.

14 An unquantified number of treatment acres are also devoted to actually reducing the perimeter of larger infestations 

from priority areas. In addition, an estimated 440,000 acres of biocontrols are established on BLM lands in Oregon, 

affecting about 30 well-established noxious weed species. 

Table 4-3. Projected Annual Acres of Effective Noxious Weed Control by Alternative

Alternative Gross Treatment 

Acres

Efficiency 

Percentage

Tentative 

Effectively 

Treated Acres

25% Right-ofWay Treatment 

Benefit

Total Effectively 

Treated Acres

Reference Analysis 42,100 .30 12,630 n/a 12,630

2 (No Action) 45,500 .60 27,300 n/a 27,300

3 57,700 .80 46,160 n/a 46,160

4 (Proposed 

Action)

57,700 .80 46,160 2,350 48,510

5 57,700 .80 46,160 2,350 48,510

Final Environmental Impact Statement, Chapter 4: Noxious Weeds and Other Invasive Plants
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 138

A precise relationship between control at this point and future spread reduction depends upon the species and the 

situation. Stopping a typical noxious weed from entering Oregon would be expected to have hundreds of times 

the benefit of the actual treatment acres. Numerous examples exist of a few plants, or a few acres, becoming 

hundreds and thousands in 10 to 20 years (Radke and Davis 2000:25). More likely, the invasion would be slowed 

or kept out of certain areas for years or decades. Radosevich (2007) notes, for example, attempts to reduce the 

overall (regional) spread of a noxious weed species are usually more effective if control tactics are focused on 

satellite populations originating from large patches. Radosevich also reports that Cousens and Mortimer (1995) 

and Moody and Mack (1988) suggest that the preferred containment strategy would be to remove satellite 

populations as they occur, since these populations expand more rapidly and potentially cover greater area than 

the front of a source population15. Because of this relationship, it is estimated that each acre of effective annual 

control would translate to a reduction of at least 10 times that amount of infested acres at some year in the future 

(Appendix 7, Denton 2009).

Effects of the Alternatives on Spread Rate and Infested Acres in 15 Years

There would be a lag time before seeing the 10 times reduction. The decrease in noxious weeds the first year 

would be no more than the 18,860-acre annual effective treatment acre difference between Alternatives 2 and 3. 

The complete 10 times (188,600 acres) reduction benefit would accrue gradually as those acres are, in effect, kept 

off the establishment part of the Invasion Curve (Figure 4-2). For this analysis, the benefit has been distributed 

over a 15-year period. That is, 100 acres of effective control treatments in 2010 are assumed to have reduced 

noxious weeds by a cumulative 1000 acres by 2025. Since treatments happen annually, they cumulatively 

would reduce weed spread so that the 18,860-acre annual program would be preventing 188,600 acres of annual 

infestation by year 15. By year 15, the annual spread rate would decrease to 7 percent and 1.9 million fewer acres 

would be infested with noxious weeds when compared to the No Action Alternative (Alternative 2) (Appendix 7).

Using the same relationships for the other alternatives and the Reference Analysis, the spread rate and acres 

infested at 15 years is estimated (Table 4-4).

15 Such control strategies have been likened to controlling spot fires out in front of a wildfire to reduce its spread rate.

Table 4-4. Projected Annual Noxious Weed Spread Rates and Acreage Changes for Each Alternative

Alternatives

Treatment 

Effectiveness

Effectively 

treated acres

% annual spread 

in 15 years

Change in 

annual spread 

(acres)1

Total acres 

infested in 15 

years2

15 yr acre 

change from 

No Action

Reference 

Analysis

30% 12,630 14% +14,670 to 

+146,700

8,559,713 +2.7 million

2 (No Action) 60% 27,300 12% 0 5,864,535 0

3 80% 46,160 7% - 18,860 to 

-188,600 4,008,058 -1.9 million

43 (Proposed 

Action)

80%4 48,510 6% -21,210 to 

-212,100

3,689,048 -2.2 million

53 80%4 48,510 6% -21,210 to 

-212,100

3,689,048 -2.2 million

1

 The effect of a change in control rate from Alternative 2 takes 15 years to be realized. Change in spread is smallest in the first year, 

increasing by a factor of 10 in 15 years.

2

 May be worst case. Actual invasion would be capped by biological saturation.

3

 Because Alternative 5 adds additional herbicides, it is more likely to effectively control noxious weeds. The amount of this difference is 

not quantified but is unlikely to lower the annual spread rate a whole percentage point.

4

 Plus the 2,350-acre incidental gain from treating such things as roadsides, administrative sites, and recreation sites.
139

Assumptions and calculations are explained in more detail in Appendix 7, Noxious Weed Spread Rate References 

and Calculations. The above estimates do not reflect increases in infestation rates likely to result from climate 

change (See the Climate Change, Projections, and Implications section in this Chapter). While climate change 

would be expected to increase the weed spread rate under all alternatives, it would also tend to increase the 

differences between the alternatives.

None of the alternatives in this EIS are predicted, by themselves, to achieve a “no net increase” in noxious weeds 

condition because, under current budget trends and priorities, many well-established infestations such as yellow 

starthistle east of the Cascades, or blackberry west of the Cascades, are not being aggressively treated on all 

ownerships, or are being treated primarily with biological controls.

Neighboring landowners and other cooperators (the State Department of Agriculture, Weed Boards, etc.) would 

be affected by implementation of any of the action alternatives in ways that could affect the weed spread 

rates calculated above. With additional herbicides available to the BLM, effective control covering entire 

geographically logical control areas would be available for more weed species. Adjacent landowners will be 

more effective at controlling species of weeds the BLM has been unable to treat under the No Action Alternative 

(Alternative 2). State and private control dollars may go further if treatments are more uniformly applied and thus 

more effective.

Changes in budget, program emphasis, efficiency, and other factors could affect these estimates, but those changes 

can only be assumed to affect each of the alternatives similarly, and thus not substantially affect the relative 

difference between the alternatives.

Native and Other Non-Invasive Vegetation 

Affected Environment

This section addresses native vegetation, primarily native vascular plants, nonvascular plants (e.g., mosses) as 

well as lichens, fungi, and other non-invasive plants such as crops.

The Pacific Northwest is among the more diverse regions in North America in environment and vegetation. 

Natural vegetation types vary from dense coastal forests of towering conifers through woodland and savannah 

to shrub steppe (Franklin and Dyrness 1988). The present-day composition and distribution of native flora is 

influenced by many factors including physical (e.g., climate, wind, geology, topography, elevation, latitude, slope, 

exposure), natural disturbance (e.g., wildlife use, insects, disease, fire, flood), and human management patterns 

(e.g., cultivation, development, domestic livestock grazing, fire suppression). A brief introduction to the native 

plant communities in Oregon is in the Biomes section earlier in this Chapter. 

Vegetation Considerations by Biome

Sagebrush Steppe: The sagebrush steppe ecosystem is considered to be one of the most imperiled of all 

ecosystems in the United States, with less than 10 percent retaining its historical structure and composition 

(Thompson 2007). Invasive plants lead to degradation, fragmentation, and loss of sagebrush communities. 

Invasive annual grasses, particularly cheatgrass (Bromus tectorum) are perhaps the greatest threat to sagebrush 

habitat in lower elevations (Thompson 2007). Native bunchgrasses and forbs have been replaced by cheatgrass on 

Final Environmental Impact Statement, Chapter 4: Native and Other Non-Invasive Vegetation
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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millions of acres in Oregon16, which in turn fuel wildland fires, killing native sagebrush, forbs and bunchgrasses 

that are not adapted to frequent intense fire. As cheatgrass and other invasive plant infestations increase, more 

native plant species are at risk of local or regional extirpation, as few sources of native seed are maintained. 

Another serious threat to native shrubs, forbs, bunchgrasses and habitats of the sagebrush steppe is the severalfold expansion of western juniper (Juniperus occidentalis), a native species previously restricted by fire. Western 

juniper depletes soil moisture and prevents the growth of other plants (Miller and Angell 1987).

Eastern Forest Biome: Native plant communities in the Eastern Forest Biome have suffered reductions in 

biodiversity and forage production due to invasive plants. Some native bunch grasses, forbs, and shrubs in this 

biome have been replaced by noxious weeds and other invasive plants such as cheatgrass, medusahead rye, 

Mediterranean sage, Scotch thistle, and knapweeds. Nearly 100 percent of forest inventory plots in this type 

showed invasive annual grasses (Donnegan et al. 2008). Ponderosa pine forests are also being threatened by the 

unnatural expansion of native western juniper at lower elevations. Juniper expansion results in reduced shrub 

abundance and reduced ground water, and contributes to loss of riparian plant species (Bedell et al. 1993).

East Side Riparian Biome: (See the Wetlands and Riparian Areas section in this Chapter).

Siskiyou Biome: The Siskiyou Biome has a Mediterranean climate with a strong marine influence. It has a 

combination of soil types including large areas of serpentine; the Siskiyou Biome is one of the most botanically 

diverse in North America (Stein et al. 2000). Approximately 2/3 of the known rare plants and fungi in western 

Oregon occur in the Siskiyou biome. This botanical diversity was a major reason for the creation of the CascadeSiskiyou National Monument in 2000. Unique plant communities in the Siskiyou biome are threatened by 

starthistles, knapweeds, thistles, brooms, puncture vine, knotweeds, Dyers woad, leafy spurge, loosestrife, false 

brome, yellow flag iris, and Sudden Oak Death.

Western Forest Biome: Dense shade producing forests are the least likely areas to provide opportunities for sunloving invasive plants to establish (Quigley and Arbelbide 1997); however, the introduction of shade tolerant 

weeds, as well as openings associated with disturbances, have lead to threats to native plants in this biome. 

A recent forest inventory shows 47 percent of plots in the coast range and 68 percent of plots in the western 

Cascades (all ownerships) have invasive plants present, and 6.2 percent of all plant cover in forests is easily 

identifiable non-native plants. The inventory sample plots indicate Himalayan blackberry is the most common 

invasive plant, covering 149,000 acres of forestland (Donnegan et al. 2008b). New openings can become infested 

before native succession can occur. Scotch broom has been shown to have the greatest documented economic 

impact to native plants in Oregon, by effectively reducing tree growth and forest production (Radke and Davis 

2000). Numerous other invasive plants including plants that thrive in forests, such as English ivy, false brome, 

and garlic mustard adversely affect the native species in this biome. In addition to forests, the Western Forest 

Biome includes diverse habitats such as sand dunes, meadows, marshes, bogs, rock outcrops, and woodlands that 

support unique native plant communities and are threatened by invasive plants.

Willamette Valley Biome: Most native vegetation of the Willamette Valley biome has been transformed by 

cultivation, timber harvest, development, and invasive plants. With only remnant populations of native plants 

remaining, many unique Willamette Valley plant communities are imperiled. These tracts tend to be fragmented 

and degraded by invasive plants. Hedgehog dogtail grass, medusahead and various thistles are examples of 

invasive plants that have replaced native species; however, Himalayan blackberry has consumed more acres than 

any other non-native species (Donnegan et al. 2008). Loss of native plant communities in the Willamette Valley 

has lead to the Federal listing of Kincaid’s lupine, Golden paintbrush and Willamette Valley daisy (USDI 2008c).

16 About 5 million acres on BLM lands east of the Cascades (see Figure 4-7 in the Fire and Fuels section later in this Chapter).
141

Susceptibility of Plant Communities to Damage from Invasive Plants

The susceptibility of native plant communities to invasion by non-native species is directly associated with the 

site capacity to support various plants (potential vegetation types), disturbances or stresses, the condition of the 

existing plant community, and the biological traits of the invader (Davis et al. 2000) as well as the potential for 

introduction of non-native seed or propagules. Potential Vegetation Types (PVT) have been identified based 

primarily on soil qualities, climate, aspect, and historic plant species. The PVTs displayed here (Table 4-5) 

correlate strongly with the biomes and are adapted from the 2005 Pacific Northwest Region Invasive Plant 

Program EIS. That EIS used classifications developed by Forest Service Ecologist Jan Henderson west of the 

Cascades, and potential vegetation groups developed for the Interior Columbia Basin Ecosystem Management 

Project (USDA, USDI 2000b; Quigley and Arbelbide 1997).

A major conclusion of the ICBEMP analysis was that, in general, grasslands, riparian areas, and relatively 

dry, open forests are more susceptible to invasive plants than are dense moist forests, high montane areas, and 

serpentine areas. The former have frequent gaps in the plant cover which favor establishment of most invasive 

plants, whereas the latter have relatively closed plant cover or have extreme climate or soils, which are tolerated 

by fewer species (Quigley and Arbelbide 1997).

Table 4-5 and Figure 4-3 provide a summary of potential vegetation types found on BLM lands in Oregon, and 

their expected susceptibility to invasion by invasive plants.

Table 4-5. Potential Vegetation Types

Potential 

Vegetation Type

Description (Biomes) Percentage of 

BLM Lands in 

Oregon

Susceptibility 

to Invasion 

Rating1

Agricultural Cropland/hay/pasture (East of the Cascades) less than 1 High

Alpine / Cold 

Forest

Alpine shrub-herbaceous (Sagebrush Steppe). Mountain hemlock, Pacific 

silver fir, Shasta red fir, Subalpine fir, Lodgepole pine (in the Siskiyou), 

Western white pine (primarily in the Western Forest, but also in Eastern 

Forest and Sagebrush Steppe)

less than 1 Low

Cool Shrub Characterized by mountain big sagebrush and shrubs, grasses, forbs, and 

sedges. It is limited by moisture availability due to low rainfall and/or 

shallow soils (primarily in Sagebrush Steppe. Also appears in Eastern 

Forest)

11.2 Moderate to 

High

Dry Grass Includes native grasslands, seeded grasslands, and cropland hay pasture. 

Characterized by bunchgrasses (primarily in Sagebrush Steppe. Also 

appears in Eastern Forest)

1.2 High

Dry Shrub Dominated by sagebrush but bunchgrass/forbs present. At lower 

elevations than cool shrub (Sagebrush Steppe)

66 High

East Side Dry 

Forest 

Douglas-fir, Ponderosa pine, Lodgepole pine (East side of the Cascades) 3.6 Moderate to 

High

East Side Moist 

Forest 

Vegetation includes transitional areas between drier, lower elevation forest, 

woodland types, and higher elevation forest types in cold forests. The 

dominant overstory species found in this group include grand fir, Douglasfir, cedar, and hemlock. (Primarily in Eastern Forest. Also appears in 

Sagebrush Steppe) 

less than 1 Moderate to 

High

Final Environmental Impact Statement, Chapter 4: Native and Other Non-Invasive Vegetation
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Potential 

Vegetation Type

Description (Biomes) Percentage of 

BLM Lands in 

Oregon

Susceptibility 

to Invasion 

Rating1

East Side 

Riparian

Shrub: mountain riparian low shrub, saltbrush riparian, willow, alder, 

sedge. Woodland: Cottonwood with willow, ponderosa pine, Douglasfir, aspen. On many sites, the non-native species have become well 

established, commonly replacing native species or exerting large influences 

on the functional dynamics of existing habitats. The linear nature of 

the riparian corridor makes it highly susceptible to invasion. (East Side 

Riparian)

1 High

Serpentine Forest: Jeffrey pine, Western white pine, Port-Orford-cedar. Non-Forest: 

Serpentine barrens and fens (Siskiyou)

less than 1 Low

Westside Dry 

Forest 

Similar to East Side Dry Forest. Douglas-fir, Ponderosa pine, Oregon 

white oak (Siskiyou and Western Forest)

6 High

Westside Moist 

Forest 

White/Grand fir, Tanoak (Siskiyou and Western Forests) 1.9 Low

Wet Forest Western hemlock, Sitka spruce (Western Forest) 6 Low

Woodland Dominated by western juniper. These sites generally have low water 

availability due to shallow soils (primarily in Sagebrush Steppe. Also 

appears in Eastern Forest)

less than 1 Moderate to 

High

Total 100% or 

15,734,988 acres

1

 High = high susceptibility to invasion. Invasive plant species invades the cover type successfully and becomes dominant or codominant even in the absence of intense or frequent disturbance.

Moderate = moderate susceptibility to invasion. Invasive plant species is a “colonizer” that invades the cover type successfully 

following high intensity fires or frequent disturbance that affects the soil surface or removes the normal canopy.

Low = low susceptibility to invasion. Invasive weed species are less likely to establish because the cover type does not provide suitable 

habitat.

Endangered, Threatened, and other Special Status Plant Species

Species designated as Special Status by the BLM include 1) those listed or proposed for listing as endangered or 

threatened under the Endangered Species Act, and 2) species designated by the State Director as Bureau Sensitive 

and requiring special management consideration to promote their conservation and reduce the likelihood and 

need for future listing under the Endangered Species Act. These are managed under provisions of the BLM’s 

Special Status Species Program (USDI 2008d). BLM policy objectives are: 1) to conserve and or recover 

Federally Listed species and the ecosystems on which they depend so that Endangered Species Act protections 

are no longer needed for these species, and 2) to initiate proactive conservation measures that reduce or eliminate 

threats to other Special Status species to minimize the likelihood of and need for listing of these species under 

the Endangered Species Act. BLM management activities must be conducted to minimize or eliminate threats 

affecting the status of the species or to improve the condition of the species’ habitat by ensuring that activities are 

carried out in a way that does not lead to a need to list the species under the Endangered Species Act. Potentially 

habitat-disturbing projects require pre-project clearances for Special Status plants. Clearances can include 

proposed project review for potential habitat and/or project site surveys. Conservation Measures included 

in Appendix 5 and referenced in the PEIS Mitigation Measures in Appendix 2 apply to Federally Listed and 

proposed threatened and endangered species and their proposed or designated critical habitat.

The Oregon BLM Special Status Species Program list (January 2008) includes 483 vascular plants, 44 fungi, 

26 lichens and 43 bryophytes (Appendix 5). Of these, 17 species of vascular plants are Federally Listed under 

the Endangered Species Act as “threatened” or “endangered,” and require formal consultation with the Fish and 
143

Figure 4-3. 

Potential

Vegetation

T

ypes

Final Environmental Impact Statement, Chapter 4: Native and Other Non-Invasive Vegetation
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 144

Wildlife Service if proposals are likely to adversely affect the species. Information from the PEIS Biological 

Assessment about the Federally Listed species has been incorporated into Appendix 5 of this EIS.

Survey and Manage

Within the range of the northern spotted owl17, Survey and Manage requirements apply to some Special 

Status species as well as to additional plants, fungi, lichens, and bryophytes. The standard generally requires 

management for species’ persistence at known sites and, where practical, requires a clearance survey prior to 

potentially harmful management activities.

Environmental Consequences

The four alternatives (and the Reference Analysis) are predicted to result in various levels of effects to non-target 

(native and other non-invasive) plant species and plant communities. Those effects are presented in this section in 

the following three distinct categories:

• Effects of herbicides on non-target plants - Non-target native and other non-invasive plants can be 

adversely affected by herbicides directed at nearby invasive plants and other target vegetation.

• Effects of invasive plants on native and other non-invasive plants - Native and other non-invasive plants 

are adversely affected by infestations of invasive plants. The degree to which the alternatives slow 

the spread of invasive plants has a corresponding and generally proportionate beneficial effect on the 

retention of functional native plant communities.

• Effects of non-herbicide treatments on non-target plants - Non-target plants can be adversely affected by 

non-herbicide treatment methods directed at nearby invasive plants and other target vegetation.

Effects Common to All Alternatives

Effects of Herbicides on Non-Target Plants

Herbicides have the potential to harm non-target plants, including plants that are culturally important, Federally 

Listed or otherwise designated as Special Status species, and those included in Survey and Manage. Some 

damage to non-target plant species from herbicide application is probable despite cautious planning and 

implementation. Herbicide impacts to non-target plants depend on (but are not limited to) the herbicide used, 

its selectivity, application rate, concentration, relative toxicity to the plants in the treatment area, likelihood of 

exposure, timing and method of application, environmental conditions during application, and plant stage of 

growth. Herbicide treatments impact non-target plants through direct application, overspray, off-site movement, 

and/or accidental spills. Potential impacts include mortality, reduced productivity, and abnormal growth. Risk 

to off-site plants from spray drift is greater under scenarios with application from greater heights (i.e., aerial 

application) or when air temperature or movement is high. Risk to off-site plants from surface runoff and 

movement through soil (leaching) is influenced by precipitation rate and timing, soil type, and application area. 

Measures taken to limit exposure, such as selective application methods (e.g., spot spraying, or wiping), typical 

application rates-that are less than the maximum allowed on the label (Table 3-1), drift reduction agents, and 

application restrictions based on environmental conditions (wind, precipitation, temperature, etc.), reduce the offtarget movement of herbicides. Standard Operating Procedures and PEIS Mitigation Measures (Appendix 2) are 

designed to minimize risk to non-target species including crops, vineyards, and orchards. 

Few studies were found on the impact of herbicides to fungi. In studies using rates similar to amounts proposed 

for use on BLM lands, fungi seem relatively unaffected by herbicides (Busse et al. 2003, Huston et al. 1998b). 

17 For BLM, generally west of the Cascades and the western portion of the Klamath Falls Resource Area.
145

The risk of herbicide contamination to wild edible mushrooms (e.g., chanterelles, matsutakes, porcinis) is 

expected to be limited because proposed herbicide use would be focused primarily on invasive plants infestations 

and rights-of–ways, rather than healthy forests where these species are dependent on the roots of conifer trees. 

Site-specific project design can minimize risks to non-target plants. Design considerations include the abundance 

and distribution of target versus non-target plant species, stage of growth (phenology) of plants, and the size of the 

treatment area, as well as physical features like soil moisture, timing of precipitation, air temperature, wind speed, 

and other factors.

Residential lands and agricultural lands, where crops (including orchards, vineyards, and pastures) are grown are 

protected from BLM applied herbicides by Standard Operating Procedures (see Appendix 2) that include no-spray 

buffers, drift reduction measures and other practices that minimize or eliminate herbicide drift or off site movement.

Certain herbicides target specific types of plants (Table 3-1), so collateral damage to non-target plants will depend 

upon their susceptibility to that herbicide. For example, dicamba targets broadleaf plants, so damage to perennial 

grasses would not be expected during normal use. Tables 3-12 and 3-13, the Risk Assessments (Appendix 8), and 

the following section summarize the potential effects to plants by active ingredient. The herbicides are grouped 

by their mode of action.

ALS-Inhibitors: Chlorsulfuron, metsulfuron methyl, and sulfometuron methyl (sulfonylureas) and imazapic and 

imazapyr (imidazolinones) work by inhibiting the activity of an enzyme called acetolactate synthase (ALS), 

which is necessary for plant growth. These five herbicides are effective at very low dosages (half ounce to a few 

ounces per acre). Because of their high potency and longevity, these herbicides can pose a particular risk to nontarget plants. Off-site movement of even small concentrations of these herbicides can result in extensive damage 

to surrounding plants, and damage to non-target plants may result at concentrations lower than those reportedly 

required to kill target invasive plants (Fletcher et al. 1996). In addition, a predominant problem with ALSinhibiting herbicides is that they can quickly confer resistance to weed populations, particularly where they are 

used extensively as the primary weed control method in cropping systems.

Synthetic auxins: Picloram, clopyralid, triclopyr, dicamba, and 2,4-D mimic naturally occurring plant hormones 

called auxins. They kill plants by destroying tissue through uncontrolled cell division and abnormal growth.

In the Pesticide Re-registration Fact Sheet–Picloram (1995), the EPA noted that picloram poses very substantial 

risks to non-target (broadleaf and woody) plants. The EPA also noted that picloram is highly soluble in water, 

resistant to biotic and abiotic degradation processes, and mobile under both laboratory and field conditions. They 

stated that there is a high potential to leach to groundwater in coarse textured soils with low organic material. Plant 

damage could occur from drift, runoff, and off-site where ground water is used for irrigation or is discharged into 

surface water (EPA 1995). The contribution from irrigation is considered inconsequential relative to off-site drift 

and runoff (SERA 2003b). Labeling restrictions resulting from these findings were implemented to reduce effects.

Because picloram persists in soil, non-target plant roots can take up picloram (Tu et al. 2001), which could affect 

revegetation efforts. Lym et al. (1998) recommended that livestock not be transferred from treated grass areas 

onto susceptible broadleaf crop areas for 12 months or until picloram has disappeared from the soil without first 

allowing seven days of grazing on an untreated green pasture. Otherwise, urine may contain enough picloram 

to injure susceptible plants. To a lesser degree, this can occur with other active ingredients such as 2,4-D, 

glyphosate, and imazapic.

Clopyralid is more selective and less persistent than picloram. Clopyralid is relatively non-toxic to aquatic plants; 

however, accidental spills may result in temporary growth inhibition of aquatic plants. As with picloram, clopyralid 

has little effect on grasses and members of the mustard family. Overall effects to non-target plants from normal 

application of clopyralid are likely to be limited to susceptible plant species in or very near the treatment area.

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Triclopyr is a selective systemic herbicide. It is used on broadleaf and woody species. It is commonly used 

against woody species in natural areas (Tu et al. 2001). Susceptible species could be impacted by drift from 100 

feet (typical BLM application rate) to 1000 feet (maximum BLM application rate) (SERA 2003c).

Two forms of triclopyr could be used with differing degrees of effects. Triclopyr BEE (butoxyethyl ester) is more 

toxic to plants than triclopyr TEA (triethylamine salt). The triclopyr BEE form is more apt to damage plants from 

runoff than other forms (SERA 2003c). Both forms have been found to decrease the relative long-term abundance 

and diversity of lichens and bryophytes. Newmaster et al. (1999) stated that drift from triclopyr could affect the 

sustainability of populations of lichens and bryophytes, where these ingredients reduced abundance. Typical 

application rates in aerial spraying were found to reduce abundance by 75 percent, variable by species. Colonists 

and drought-tolerant species were more resistant than the mesophytic forest species, which means that aerial 

applications of triclopyr could essentially push back the successional stage on non-vascular communities.

Triclopyr BEE was found to inhibit growth of three types of ectomycorrhizal fungi associated with conifer roots at 

concentrations of 1,000 parts per million in laboratory experiments (Estok et al. 1989). Busse et al. (2003) found 

no inhibition of ectomycorrhizal formation in a laboratory experiment using this active ingredient. Newmaster et 

al. (1999) reported that moss and lichen abundance and richness were not or nearly not affected at six months, one 

year, or two years after treatment except when very high rates of triclopyr were used.

2,4-D (salts and esters) is a selective herbicide that kills broadleaf plants, but not grasses. It has a long history of 

use and is relatively inexpensive. Direct spraying of non-target plant species is the highest potential for damage 

due to 2,4-D application. Drift could damage non-target species close to the application site (much less than 100 

feet) although some species such as grapes are more susceptible. One study determined that 2,4-D could affect 

three species of ectomycorrhizal fungi in laboratory experiments (Estok et al. 1989).

Dicamba is a selective, systemic herbicide that can affect some annual, biennial, or perennial broadleaf and 

woody species as well as annual grasses. Susceptible plants are likely to be damaged by direct sprays and drift. 

The greatest risks to aquatic plants are associated with runoff, but are highly site specific. Wind erosion may 

cause impacts in arid regions (SERA 2004g). Drift may cause damage to susceptible species at distances less than 

100 feet from the application site. Vaporized or volatilized dicamba can affect non-target plants. Vaporization 

does affect vegetation, but much more study in air concentration-duration relationships needs to be done to 

quantify the level of effects. Vaporization potential will be dependent on atmospheric stability and temperature. 

Dicamba vapor has been known to drift for several miles following application at high temperatures (Cox 1994).

Photosystem Inhibitors: Bromacil, diuron, hexazinone, tebuthiuron, and diquat kill target plants by disrupting 

photosynthesis. Bromacil and diuron are non-selective, broad-spectrum systemic herbicides, which are lethal to 

all plants. Both pose a high risk to non-target species in the immediate vicinity of the treatment area.

Hexazinone has differential toxicity to plants and is effective against woody species. It is primarily absorbed 

through the roots of the plant.

Tebuthiuron is relatively non-selective against broadleaf plants, woody plants, and grasses. Tebuthiuron can be 

selective at low rates of application where it is used to thin sagebrush stands allowing more herbaceous species 

to thrive in the interspaces. Only the highest application rates of tebuthiuron produced an effect on non-target 

mycorrhizal fungi but there was no measurable effect of any level of tebuthiuron on germination of spores 

collected after six months (Allen and West 1993).

Diquat would be used by BLM only on aquatic weeds. It kills the plant parts that it comes in contact with, but 

does not kill the roots, so it is effective only for single season control. It is non-selective and is used in water 

sources where few native aquatic plants are present.
147

EPSP Synthase Inhibitor: Glyphosate prevents plants from synthesizing three aromatic amino acids including a key 

enzyme, EPSP (5-enolpyruvylshikimate-3-phosphate). Glyphosate is a non-selective, systemic herbicide that can 

damage all groups or families of non-target plants to varying degrees, most commonly from off-site drift. Plants 

susceptible to glyphosate can be damaged by drift up to 100 feet from the application site at the highest rate of 

application proposed. Species that are more tolerant are likely to be damaged at distances up to 25 feet (SERA 2003a). 

Non-target species are not likely to be affected by runoff or absorption from soil. Glyphosate strongly adsorbs to soil 

particles, which prevents it from being taken up from the soil by plant roots (Tu et al. 2001, SERA 2003a).

Field studies conducted using glyphosate found no effects to plant diversity in an 11-year study on site preparation 

using herbicides, though the structural composition and perennial species’ presence were changed (Miller et al. 

1999). Newmaster et al. (1999) reported that moss and lichen abundance and richness were not or nearly not 

affected at six months, one year, or two years after treatment except when very high rates of glyphosate and 

triclopyr were used.

Glyphosate was found to inhibit growth of three types of ectomycorrhizal fungi associated with conifer roots at 

concentrations of 1,000 parts per million in laboratory experiments (Estok et al. 1989). Houston et al. (1998) 

documented responses of below-ground fungal community structure (richness, diversity, composition) were 

similar in untreated and treated (with glyphosate and triclopyr) stands although total fungal abundance was not 

changed, isolation frequencies (the abundance measure used) in organic soil of two fungal species decreased when 

samples were collected two years after herbicide treatments.

Carotene Inhibitor: Fluridone, an aquatic herbicide, kills target plants by preventing them from synthesizing 

food; however, at low concentrations native pondweeds may escape harm (Farone and McNabb 1993). It is used 

primarily to control Eurasian water milfoil (present in Oregon) and hydrilla, (which is not yet known in Oregon 

but present in surrounding states). Fluridone must remain in contact with target aquatic species for an extended 

period for effective control and poses only low risk from a spill at maximum application rate to plants in a pond. 

Risks to terrestrial plants could not be evaluated due to lack of toxicity testing. Off-site deposition rates suggest 

that small amounts of the herbicide would drift offsite potentially affecting terrestrial plants.

Auxin transport inhibitor: Diflufenzopyr acts by disrupting the delicate auxin balance needed for plant growth. 

It is selective for annual broadleaf weeds and suppression of annual grasses and perennial broadleaf weeds. 

Although diflufenzopyr is a weak herbicide, when formulated with dicamba, it can reduce the amount of herbicide 

needed from 1-2 pounds per acre of dicamba alone to .26-.35 pounds per acre of diflufenzopyr + dicamba.

Effects of Invasive Plants on Native and Other Non-Invasive Plants

Native plant communities are in dynamic balance, where plants, animals, and organisms keep each other in 

check. Each plant is part of a complex food chain; break one of the links and others are likely to be adversely 

affected. One disappearing plant can take with it up to thirty other species that depend on it, including insects, 

higher animals and even other plants (Wood 1996). Invasive plants are typically introduced into these ecosystems 

without the plants, animals, and diseases they evolved with, giving them a competitive advantage. The resulting 

invasion displaces native and other non-invasive plants, adversely affecting the composition and structure of the 

plant community and thus the other elements of the ecosystem dependent upon it. Adverse effects begin gradually 

and are often well underway by the time the effects become apparent or significant. At that point, restoration is 

expensive and often not possible because of the loss of the supporting ecosystem components such as soil depth 

and water table. Once a threshold is exceeded, permanent loss of historical plant association and the organisms 

that depend on them occurs (Appendix 7). The impact of invasive plants can be permanent when economic and 

environmental factors limit the ability of a managing agency to restore the ecosystem to a healthy state (NAS 

2002). The fewer invasive plants present, the more likely it is that restoration is possible.

Final Environmental Impact Statement, Chapter 4: Native and Other Non-Invasive Vegetation
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 148

Society is dependent upon native ecosystems. The ability of Oregon’s landscapes to produce goods and services 

including clean water and air is dependent upon the healthy functioning of Oregon’s native plants and ecosystems. 

Noxious weeds have infested 1.2 million acres of native ecosystems on BLM lands in Oregon, and other invasive 

plants, notably cheatgrass, have infested 5 million more, eliminating or substantially reducing the natural function 

and productivity of those lands for the foreseeable future.

Remaining native ecosystems are currently stressed by increasing demand for goods and services, heavy visitor 

use, human development, altered fire regimes and increased fire intensities, climate shifts, and the rapid spread 

of invasive plants. The anthropogenic rate of species’ invasions far exceeds the natural background rate and 

is accelerating (Lodge and Shrader-Frechette 2003). Exotic [non-native] plants were rated as one of the six 

primary elements of global change (Vitousek et al. 1997). The International Union for the Conservation of 

Nature (IUCN)18 notes that a significant proportion of species now considered extinct were driven to extinction by 

invasive species, and generally ranks invasive species as one of the top ten threats to currently threatened species 

(IUCN 2008). Noxious weed infestations are expanding and are estimated to be infesting 144,000 additional 

acres each year on BLM lands in Oregon.

Many invasive plants modify invaded sites, so that the site becomes inhospitable to the original plant community. 

Saltcedar and perennial pepperweed are known to extract salts from deep in the soil and deposit it on the surface 

making the site unsuitable for native plants. Knapweeds and starthistles are known to increase sheet erosion 

and produce chemicals that prevent other species from germinating (Boersma et al. 2006). Reed canarygrass 

decreases species’ diversity, and reduces the structural complexity of the plant community through its aggressive, 

rapid growth and ability to eliminate safe sites for the establishment of native plants (Hovick and Reinartz 2007). 

Grasses in particular can limit the establishment and growth of woody species (D’Antonio and Vitousek 1992). 

Grass invasions prevent the re-establishment of forests following abandonment of agricultural and pastoral land 

(D’Antonio and Vitousek 1992).

Most invasive plants are known for forming monocultures, but even where invasive plants do not ultimately 

dominate plant communities, they can adversely influence succession. For example, Scotch broom initially 

forms a dense canopy on harvested forest sites, shading out regenerating conifers and other plants. As the broom 

ages and the canopy opens, there is a partial recovery of ground cover, though not by all pre-existing species 

(Smith 1994). Shade tolerant Himalayan blackberry germinates under dense Scotch broom plants and frequently 

becomes dominant on those sites. Blackberry fruit is a seasonal food source for introduced starlings and rats and 

the vines shelter them from predation. Even after the blackberries overtake the Scotch broom, long-lived scotch 

broom seed remains viable for decades, ready to respond to future disturbances.

Natural disturbances are important to ecosystem renewal, and invasive plants alter historic disturbance regimes. 

Many plant communities are adapted to fire cycles, with fires maintaining the full range of successional stages, 

species, and habitats. Invasive plants can interfere with this process by maturing, drying and then burning earlier 

in the season, burning more often, and burning hotter. They also directly compete with the various native plant 

seedlings that would have naturally followed the disturbance. Similarly, landslides, high flows, and stream bank 

erosion are natural processes that shape stream courses and deposit large wood in streams. When invasive plants 

prevent native plants from repopulating these disturbed sites, accelerated erosion and watershed degradation is the 

result. Even in old-growth forests where the most common natural disturbance pattern is the small gaps created as 

individual large trees die or fall, invasive plants are interfering with the reestablishment of the native hardwoods 

and conifers important to maintaining the multi-layered structure of these stands (Hobbs and Huenneke 1992). 

18 The IUCN, also known as the World Conservation Union, is the world’s main authority on on the conservation status of 

species. The IUCN is comprised of 83 states, 108 government agencies, 766 Non-governmental organizations and 81 

international organizations and about 10,000 experts and scientists from countries around the world. The IUCN Red List is 

widely considered the most objective and authoritative system for classifying species in terms of the risk of extinction.
149

Flying squirrels and other spotted owl prey species, for example, rely on the cover provided by this intermediate 

crown layer to reach and utilize the upper forest crown layer; prey species and owl numbers decrease when this 

layer is not present. This natural process is threatened by noxious weeds such as tansy ragwort, thistles, and rush 

skeletonweed, which can be spread great distances by wind, even in forestlands. Weed seeds are also carried by 

water and wildlife (Asher and Spurrier 1998).

Native ecosystems on BLM lands may also suffer when invasive plants spread from BLM lands. Adjacent 

landowners may control these weeds with less environmentally friendly methods or products, or by using more 

herbicides to combat invading plants than would be needed if all ownerships were participating. Collateral 

damage may occur near property lines, and landscape-scale values such as watershed or wildlife values may be 

degraded by these well-intended treatments, particularly west of the Cascades where the checkerboard ownership 

often means the BLM manages no more than 50 percent of any watershed. In addition, native and other noninvasive plants including crops on adjacent lands can suffer irreparable damage when uncontrolled invasive plants 

from BLM lands move across property lines. Private ranches east of the Cascades have been abandoned after 

native and other non-invasive forage and croplands were taken over by invasive plants, and tens of thousands of 

dollars of effort have not been able to restore them (Asher and Spurrier 1998).

Federally Listed and other Special Status species are particularly at risk from noxious weeds and other invasive 

plants. Rare species generally display narrow ecological amplitudes, keeping them geographically restricted and 

unable to compete over a wide range of site conditions. When invasive plants invade those sites, fragmentation 

of populations and extirpation often result. Although the protection of sites known to be occupied by Special 

Status species is a priority for BLM weed control efforts, success of those efforts will vary depending upon the 

likelihood of those sites being invaded and whether effective weed control tools are available.

The degree to which these effects apply to the various alternatives is primarily a function of, and directly 

proportional to, the number of acres that will become infested with weeds under each alternative. Adverse effects 

caused by weeds currently apply to the 1.2 million acres of BLM lands in Oregon currently infested with noxious 

weeds, and to more than 5 million acres infested with other invasive weeds – primarily cheatgrass. As described 

in the Noxious Weeds and Other Invasive Plants section in this Chapter, the various alternatives are predicted to 

affect the spread rate of noxious weeds and thus the acres projected to be infested in 15 years (Table 4-6). These 

projections are designed to show the relative difference between the alternatives in this EIS, and may not apply if 

funding levels or other factors change from current levels.

Table 4-6. Projected Noxious Weed Spread Rates and 15-Year Infested Acres for Each Alternative1. 

Alternatives

% annual spread of 

noxious weeds in 15 

years

Total acres noxious 

weeds in 15 years2

Acreage difference 

from No Action

Proportion of BLM 

lands infested in 15 

years

Reference Analysis 14% 8,559,713 2.7 million more 1/2

2 (No Action) 12% 5,864,535 0 1/3

3 7% 4,008,058 1.9 million less 1/4

4(Proposed Action) 6% 3,689,048 2.1 million less 1/5-1/4

53 6% 3,689,048 2.1 million less 1/5-1/4

1

 Noxious weeds currently infest 1.2 million acres of BLM lands in Oregon.

2

 Calculated from spread rate; does not reflect the potential for biological saturation. 3 Because Alternative 5 adds additional herbicides, it is more likely to effectively control noxious weeds. The amount of 

this difference is not quantified but is unlikely to lower the annual spread rate a whole percentage point.

Final Environmental Impact Statement, Chapter 4: Native and Other Non-Invasive Vegetation
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 150

Effects of Non-Herbicide Treatments on Non-Target Plants

Under each alternative, half or more of the invasive plant treatments are projected to be done without herbicides. 

These treatments can have less risk to non-target plants and provide effective control for about 1/3 of the noxious 

weeds in Oregon. However, non-herbicide treatments have their own set of potential environmental effects. 

The extent to which non-herbicide treatment methods directly affect non-target plants varies by the amount and 

method of treatment as well as the treatment timing, site conditions, and relative abundance of plants present. 

Minimizing impacts to native and other non-invasive plants allows them to recapture the site more quickly and 

reduces the need for additional weed control treatments.

Manual treatments tend to be selective and result in minimal damage to non-target plants including minor trampling, 

breakage and occasional mortality to individuals, as well as light soil disturbance that could increase the germination 

of any seeds present. Manual treatments are labor intensive and usually only practical on small areas.

Mechanical treatments involving chainsaws or similar hand operated equipment can be focused on target plants, 

thus having similar effects as manual treatment. Mechanical treatments like mowing are typically non-selective, 

and remove or damage target and non-target plants alike. Mechanical treatments have limited use for noxious 

weed control unless coupled with other treatments. Machinery can disturb vegetation and soil, prepare seedbeds, 

spread seeds, and increase sprouting and reproduction from root fragments. Mechanical treatments (and other 

ground-disturbing treatment such as directed livestock) can break up soil crusts. As discussed in more detail in 

the Soil Resources section in this Chapter, biological crusts provide several important functions within, and on, 

the surface of soil in arid and semiarid environments such as the Sagebrush Steppe and Eastern Forest Biomes. 

The major components of the crust are cyanobacteria, green algae, microfungi, mosses, liverworts, and lichens. 

Disturbance of crusts can come about through trampling, fire, or burial by windblown soil.

Prescribed Fire is normally used for weed control only on heavily infested sites, because most invasive plants 

are adapted to fire and readily invade disturbed sites. Prescribed fire for weed control19 can be most effective if 

followed by herbicide treatments of new weed germinates; seeding of native species is usually required. Native 

species adapted to fire may remain, and the selection of a follow-up herbicide would be designed to minimize 

damage to remaining native plants where possible. Adverse effects to native plants include injury, mortality, 

nutrient flush or loss of nutrients, reduced shading, and potential increases of invasive plants.

Directed livestock grazing can effectively reduce the vigor and seed production of invasive weeds, but is not 

likely to supply long-term control. Multiple treatments from directed livestock may increase risks to native plants 

by reducing vigor and seed production of non-target species and the ground disturbance can increase the potential 

for reinvasion and damage soil crusts. Alternately, disturbance from directed grazing could provide positive 

benefits by preparing a seedbed for seeding competitive native species. 

Seeding or Planting is used to restore native vegetation or introduce desirable vegetation. The effect of these 

treatments varies from simply adding seed via aerial broadcast to destruction of existing vegetation. Typically, a 

rangeland drill is used to seed, with only minor damage to existing plants. Successful revegetation can be difficult 

on rangelands due to arid and semiarid conditions, and minimal seedbed preparation (to maintain existing native 

plants) leading to increased competition. Native seed collected on site protects the genetic integrity of local 

19 This discussion does not include the prescribed fire used on tens of thousands of acres per year to manage fuels and 

native vegetation levels. Some prescribed fires can have both objectives however, such as the spray, prescribed fire, and 

restoration scenario planned for several thousand acres per year on cheatgrass and medusahead to reduce fire hazard in 

the wildland urban interface under Alternatives 3-5 using imazapic. 
151

alleles. Native seed from other locations could alter locally evolved adaptations; however, non-native seed may 

be used following NEPA analysis that documents the need for other than native seed (USDI 1992a), primarily to 

protect the soil resource and subsequent site potential.

Effects by Alternative

Reference Analysis – No Herbicide Use

Effects of Invasive Plants on Native and Other Non-Invasive Plants: In general, the loss of native plants, and 

the goods and services they provide, would be proportional to the acres projected to become infested under 

this alternative. Under the no-herbicide Reference Analysis, the rate of spread of noxious weeds is projected 

to increase to 14 percent annually (up from the current 12 percent), and noxious weeds are projected to occupy 

approximately 1/2 of all BLM lands in Oregon within 15 years (Table 4-6). These numbers do not include the 

current five million acres infested with other invasive plants that would continue to spread at an increased rate 

under a no-herbicide strategy as well. Approximately 2/3 of the noxious weeds in Oregon cannot be effectively 

controlled with non-herbicide methods (Appendix 7: Table A7-1); therefore, native ecosystems being invaded 

by those species would suffer a higher level of infestation and resultant adverse effects than under alternatives 

with herbicide use. For example, aggressive, non-native grasses like medusahead, cheatgrass and hedgehog 

dogtail would continue to invade imperiled sagebrush and oak woodlands in the Sagebrush Steppe, Willamette 

Valley, and Siskiyou Biomes relatively unchecked, because effective treatments would not be available without 

herbicides. Similarly, the Warner Wetlands and numerous riparian areas would continue to be over-run by 

perennial pepperweed, whitetop and saltcedar as effective treatments would be unavailable. Japanese knotweed, 

Himalayan blackberry, and non-native grasses would continue to invade and degrade riparian areas and 

susceptible habitats like the West Eugene Wetlands. Federally Listed and other Special Status species would be 

particularly at risk because of the BLM’s inability to effectively respond to specific weed threats.

Effect of Non-Herbicide Treatments on Non-Target Plants: Non-herbicide methods for the control of invasive 

plants are highest under this strategy, 42,100 acres versus 28,800 under the No Action Alternative (Alternative 

2), as districts replace 75 percent of the Alternative 2 herbicide acres with non-herbicide methods. An estimated 

3,600 acres of this increase would be direct seeding. Seeding with native species is expected to have minimal 

negative effect on native plant communities. In the absence of herbicides for weed control, districts east of the 

Cascades would increase the use of directed livestock grazing by 6,000 acres over current levels controlling 

weeds but causing some collateral damage to native plants. Mechanical and manual treatment methods would 

also increase, 1,600 and 1,300 acres per year (59 and 46 percent) respectively, compared to the No Action 

Alternative, potentially increasing short-term damage to, and loss of, non-target plants, especially with nonselective mechanical methods.

The potential adverse effects of prescribed fire for weed control (e.g., loss of non-target species, site disturbance) 

would be reduced under this alternative, as the use of this method decreases 2,000 acres per year because followup herbicides would not be available.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Effects of Herbicides on Non-Target Plants: The four herbicides available under this alternative have risks to nontarget plants (Tables 3-12 and 3-13). Treatments to slow the spread of noxious weeds would hamper restoration of 

habitats if non-target plants were seriously damaged or destroyed. However, treatments using selective herbicides 

would typically have less risk of harming non-target plant types than non-selective herbicides. Most applications 

would be spot spraying to directly target the noxious weed plants. Since herbicide use in this alternative is limited 

Final Environmental Impact Statement, Chapter 4: Native and Other Non-Invasive Vegetation
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 152

to noxious weeds, broadcast applications would be limited to expanses (monocultures) of noxious weeds. Other 

invasive plants, like cheatgrass, would usually not be controlled with herbicides because no selective herbicide is 

available that would protect native forbs and shrubs.

Effects of Invasive Plants on Native and Other Non-Invasive Plants: In general, the loss of native plants would 

increase proportional to the acres projected to become infested. Under Alternative 2, noxious weeds are projected 

to continue spreading at a rate of 12 percent annually, and approximately 1/3 of all BLM lands in Oregon are 

projected to be infested within 15 years (Table 4-6). This does not include the current five million acres infested 

with other invasive plants that would continue to spread under this alternative. These averages would apply to 

most but not all plant communities. Sixteen of the 120 State listed noxious weeds cannot be effectively controlled 

with the four herbicides or the non-herbicide methods available under this alternative, and herbicides cannot be 

used on invasive plants such as cheatgrass. Most significantly, perhaps, the invasive annual grasses medusahead 

and cheatgrass would continue to spread unchecked, converting additional remnant sagebrush steppe, oak 

savannah, and other dry habitats to annual grass monocultures. These monocultures increase the fire hazard in 

many wildland urban interfaces. Restoration treatments of susceptible wetlands and riparian habitats are also 

hampered, as the four herbicides available under this alternative are not very effective at controlling saltcedar, 

watermilfoil, hydrilla, perennial pepperweed, and other noxious weeds occurring in these areas. Native plant 

communities infested with these species will suffer loss of native species and alteration of community function in 

the long term almost regardless of the level of effort or priority given to their conservation. Habitats of Federally 

Listed and other Special Status species (Appendix 5) would be particularly at risk from these invading non-native 

species because of their limited geographic range and narrow ecological amplitude.

Effect of Non-Herbicide Treatments on Non-Target Plants: Effects would remain essentially unchanged from 

current levels, and would be as described under effects common to all alternatives. Treatment methods creating 

soil disturbance and likely to result in some mortality among native plants include 6,100 acres of prescribed 

fire, 2,800 acres of directed livestock, 3,500 acres of mechanical treatments (including chainsaws), 2,200 

acres of manual treatments, and seeding if it relies on non-native seed. Since non-herbicide methods are often 

implemented where herbicide damage to adjacent plants or other resource values would be unacceptable (e.g., 

Special Status plants), it is likely that collateral mechanical damage to those same resources from non-herbicide 

treatment methods would be more significant than the same level of damage in an average landscape. Such 

effects would be unavoidable, and would be balanced with the benefits of weed control during NEPA analysis at 

the project-specific level.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Effects of Herbicides on Non-Target Plants: Of the additional 13,600 acres that would be treated with herbicides 

under this alternative when compared to Alternative 2 (No Action), 11,000 acres would be with imazapic east 

of the Cascades to control monocultures of invasive annual grasses. Imazapic has a low-to-moderate risk of 

harming non-target plants (Table 3-12), and at low rates, can be used to control these grasses with little adverse 

effect to remaining non-target native forbs and shrubs. This would significantly aid restoration efforts where these 

grasses only partially occupy the site. Acres of 2,4-D, picloram, glyphosate, and dicamba would decrease under 

this alternative compared to Alternative 2 (Table 3-3), and the additional eight herbicides west of the Cascades 

and nine herbicides east of the Cascades are mostly selective herbicides that would allow for more target-specific 

treatments, decreasing the risk to non-target plant types.

Effects of Invasive Plants on Native and Other Non-Invasive Plants: In general, the loss of native plants would be 

proportional to the acres projected to become infested. Under Alternative 3, the rate of spread of noxious weeds is 

projected to decrease to 7 percent annually (down from the current 12 percent), infesting approximately 1/4 of all 
153

BLM lands in Oregon in 15 years (Table 4-6). This does not include the five million acres currently infested with 

other invasive plants that would continue to spread (presumably at a slightly decreased rate) under this alternative. 

These spread rates would apply to most plant communities, since this alternative could effectively target 116 of 

the 120 State listed noxious weeds in Oregon.

With the ability to effectively control almost all noxious weeds and other invasive plants would come the ability 

to more consistently protect native plant communities in specific geographic areas, such as traditional food 

gathering areas or in Special Status species’ habitats. The herbicides available under this alternative would also 

make cooperative projects with adjacent landowners more feasible, resulting in better protection for Special Status 

and other native plant communities both on and off BLM lands.

Effect of Non-Herbicide Treatments on Non-Target Plants: The methods and acreage of non-herbicide invasive 

plant control treatments is similar to Alternative 2 (No Action) except for a projected 7,000 acre increase in 

prescribed fire and corresponding 5,000 acre increase in seeding or planting, both related to the availability of 

imazapic for the control of medusahead rye, cheatgrass, and other invasive annual grasses. With imazapic, it 

becomes practical to restore medusahead-infested sites primarily in the Sagebrush Steppe Biome by burning, 

spraying, and seeding. One objective of some of these treatments would be to reduce the annual grass fire hazard 

adjacent to communities and other developments. Any increase in negative effects to non-target species (from 

Alternative 2) would be related to this 7,000-acre increase in burning. The combination of treatments would 

reduce the survival of native herbaceous and woody species that were not adapted to fire. Remnant perennial 

bunchgrasses and forbs would likely survive burning and spraying, benefiting from reduced competition and the 

increase in available nutrients. Additional restoration would rely on the success of seeded species. Sites would 

generally only be worse off if the seeding fails.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

Effects of Herbicides on Non-Target Plants: Under Alternative 4, an additional 14,800 acres of herbicide 

treatments would occur when compared to Alternative 3. Nearly two-thirds of these additional treatments would 

be to treat native or other non-invasive vegetation in rights-of-way, administrative sites, and recreation sites. 

In rights-of-way, treatment is more likely to be done by boom spray (or similar broadcast method) rather than 

applying herbicides to individual plants. The risk to non-target plants from direct herbicide spray is moderate 

to high for almost all of the herbicides available under this alternative (Tables 3-12 and 3-13). Some of the 

herbicides available are relatively non-selective (Table 3-1), and would kill all inadvertently treated plants in the 

treatment area. Diuron, glyphosate, hexazinone, imazapyr, and sulfometuron methyl would be used statewide, 

and bromacil and tebuthiuron would only be used east of the Cascades. However, the use of herbicides in rightsof-way, administrative sites, and recreation sites may have negligible effects on native plants as these habitats 

are currently managed in early seral condition (primarily by mechanical methods). That said, early seral Special 

Status species that are growing on roadsides and similar sites because they are maintained in an early seral 

condition with non-herbicide treatments such as mowing would be at risk of damage from herbicides. Policyrequired pre-project clearances would mitigate most of this risk. 

Under this alternative, herbicides would be used on an estimated 5,700 acres annually to restore habitats as 

described in Conservation Strategies for Federally Listed and other Special Status species. While herbicides 

used could have risk to non-target plants, applications would be specifically designed to improve overall habitat 

conditions.

Other effects of herbicides on non-target plants under this alternative would be the same as described for 

Alternative 3.

Final Environmental Impact Statement, Chapter 4: Native and Other Non-Invasive Vegetation
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 154

Effects of Invasive Plants on Native and Other Non-Invasive Plants: In general, the loss of native plants would be 

proportional to the acres projected to become infested. Under Alternative 4, the rate of spread of noxious weeds 

is projected to decrease to 6 percent annually (down from the current 12 percent), and approximately 1/5-1/4 of all 

BLM lands in Oregon would be infested within 15 years (Table 4-6). This does not include the five million acres 

currently infested with other invasive plants that would continue to spread (presumably at a slightly reduced rate) 

under this alternative. The additional herbicides available under this alternative (one west of the Cascades; three 

east of the Cascades) are generally designed for vegetation control in rights-of-ways and other developed areas. 

Because right-of-way treatments would incidentally control noxious weeds and other invasive plants on primary 

spread routes, the benefit to native plant communities is higher than Alternative 3, with 300,000 fewer acres 

projected to be infested with noxious weeds in 15 years.

Effect of Non-Herbicide Treatments on Non-Target Plants: The amount of non-herbicide treatments projected to 

take place for the control of invasive plants, and their effect on non-target plants, is the same as for Alternative 

3. However, this alternative would also make herbicides available to control native and other non-invasive 

vegetation along rights-of-ways, administrative sites, and recreation sites. Such treatments would reduce nonherbicide treatments currently being done in those areas on an acre-for-acre basis (see Table 4-7 below, adapted 

from Table 3-8 in the Management of Native and other Non-Invasive Vegetation subsection of the Assumptions 

about Herbicide Treatments section in Chapter 3). The alternative would also make herbicides available for certain 

habitat improvements, reducing current non-herbicide treatments by about 35 percent of the proposed herbicide 

acres. The assumed net change in treatment acres when compared to Alternative 3 is shown in Table 4-7.

Table 4-7. Estimated Change in Native1 Vegetation Annual Treatment Acres by Treatment Method under

Alternative 4 (Proposed Action) When Compared to Alternative 2 (No Action)

Method

 Treatment of native vegetation 

on rights-of-way, administrative 

sites, and recreation sites under 

Alternative 4 

 Treatment of native vegetation 

for habitats as described in 

Conservation Strategies under 

Alternative 4 

Total native vegetation treated 

under Alternative 4 

 East2 West2 East West East West 

Herbicides 7,500 1,900 5,500 200 13,000 2,100 

Mechanical -6,750 -1,710 -1,155 -42 -7,905 -1,752

Manual -750 -190 -770 -28 -1,520 -218

Net change in total 

native vegetation 

acres treated 0 0 3,575 130 3,575 130 

1

 And other non-invasive vegetation.

2

 East/West of the Cascades.

For the rights-of-ways, administrative sites, and recreation sites, herbicide use does not reduce non-herbicide 

treatment risks to non-target plants, because current non-herbicide treatments are within the disturbed clearing 

limits for rights-of-way anyway. An exception might be thought to occur where a Federally Listed species occurs 

within one of these disturbed areas. However, such a site, if known, would be protected under all treatment 

scenarios, so there would be no effect.

For identified habitat improvement treatments, the reduction in mechanical and manual treatment acres would 

reduce the likelihood of soil disturbance and related damage to existing native plants (and soil crusts) on nearly 

2,000 acres. Since these treatments would be specifically designed to restore native habitats, and would involve 

Special Status species for whom habitat improvement efforts would necessarily require a particularly low level of 

risk, the likelihood of significant or long-term damage to native plants would be very low.
155

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Effects of Herbicides on Non-Target Plants: The effects of this alternative to non-target native plants would be 

similar to the effects described under Alternative 4 (Proposed Action). East of the Cascades, acres of 2,4-D and 

imazapic (both selective herbicides) would both increase by 2,000 acres; however, there is low to moderate risk 

to non-target plants that are directly sprayed with imazapic, and no to low risk for off-site drift. Two additional 

herbicides (diflufenzopyr + dicamba and diquat) become available east of the Cascades and five additional 

herbicides (diflufenzopyr + dicamba, diquat, bromacil, chlorsulfuron, and tebuthiuron) become available west 

of the Cascades. All but dicamba have a moderate to high risk of harming non-target vegetation when directly 

sprayed; for dicamba these risks would be limited to susceptible plants. However, given the limited number of 

acres that would be sprayed with these, additional adverse effects would be limited.

Effects of Invasive Plants on Native and Other Non-Invasive Plants: In general, the loss of native plants would 

be proportional to the acres projected to become infested. Like Alternative 4 (Proposed Action), the spread rate 

of noxious weeds under Alternative 5 is projected to decrease to a rate of 6 percent annually (from the current 12 

percent), and approximately 1/5 to 1/4 of all BLM lands in Oregon would be infested within 15 years. This does 

not include the five million acres currently infested with other invasive plants, that would continue to spread (but 

presumably at some reduced rate) under this alternative. The additional herbicides available under this alternative 

(five west of the Cascades; two east of the Cascades when compared with Alternative 4) would provide options 

for weed control and help prevent infestations from developing resistance to specific herbicides20. Nevertheless, 

this increase would not be expected to change the BLM’s ability to reduce the spread of noxious weeds and other 

invasive plants by a full percentage point, so the gain is not estimated.

Effect of Non-Herbicide Treatments on Non-Target Plants: The effects of this alternative to non-target native 

plants is similar to those described under Alternative 4 (Proposed Action), except that the additional 4,800 acres of 

herbicide use would be expected to reduce current non-herbicide treatments by about 1,700 acres (Table 4-7). For 

identified habitat improvement treatments, the reduction in mechanical and manual treatment acres would reduce 

the likelihood of soil disturbance and related damage to existing native plants. Since these sites may not be 

infested with noxious weeds or other invasive plants, the likelihood of damage to native plants is higher; however, 

treatments would be designed to increase these more desirable species, so the short-term impact should result in 

long-term improvements in habitat and land health. Fuel reductions and other treatments could also be conducted 

with herbicides under this alternative, and potential effects to non-target vegetation would be a site-specific 

consideration.

Endangered, Threatened, and other Special Status Plant Species

Vegetation management practices have the potential to affect Special Status plants, and to a lesser degree, 

Survey and Manage species within the range of the northern spotted owl. Any management action focused on 

preventing, reducing, or eliminating the spread of noxious weeds and invasive plants will directly or indirectly 

benefit these species. 

Effects from vegetation treatments are similar for all Special Status and Survey and Manage plants. Federally 

Listed and other Special Status species are more at risk from herbicides because their populations may be limited 

20 More specifically, having more than one herbicide available to treat a specific weed species helps prevent the treated 

population from persisting in the form of a few individuals (and their progeny) that may be materially resistant to a 

particular herbicide.

Final Environmental Impact Statement, Chapter 4: Native and Other Non-Invasive Vegetation
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 156

in geographic scope, and thus damage to individuals may have population implications. Pre-project clearances 

and protection of occupied or assumed occupied habitats required by Special Status Species Program and Survey 

and Manage direction should prevent most or all adverse effects. The vast majority of treatments can be designed 

to reduce or eliminate adverse effects to these species; however, adverse effects could occur under any alternative 

for some treatment methods on some individuals. Some projects would have short-term adverse effects to 

individual plants in order to gain long-term benefits for the species. For example, habitat improvement projects 

or reducing competition from invasive plants may injure individual plants. In most cases effects to individuals 

would be mitigated by Standard Operating Procedures, PEIS Mitigation Measures, and Conservation Measures 

from the PEIS Biological Assessment (e.g., no-herbicide buffers, timing of treatments, use of selective herbicides, 

exclosures, spot treatments that avoid Special Status plants, or avoiding or prohibiting aerial applications).

In general, plants in the sunflower, legume, and mustard families tend to be more susceptible to broadleaf 

herbicides. Therefore, there may be increased risk from these herbicides for Federally Listed species such as 

Kincaid’s lupine, and Applegate’s milk-vetch in the legume family; Willamette valley daisy and Malheur wirelettuce of the sunflower family; and, MacDonald’s rock-cress and Howell’s spectacular thelypody of the mustard 

family. The ALS-inhibiting herbicides are highly active, and extremely low concentrations could injure Special 

Status or Survey and Manage plants. Chlorsulfuron may cause severe reduction in seed production of some nontarget crops if they are exposed at critical stages of development (Fletcher et al. 1993). Rare or susceptible annual 

plants in particular may suffer if they are unable to produce seed due to exposure to chlorsulfuron. Conservation 

measures for these herbicides are designed to prevent damage to Federally Listed species (see Appendix 5). 

Buffer distances up to 900 feet are prescribed. Metsulfuron methyl is known to be harmful to commercial onion 

crops of the lily family, so other plants in that family like western lily and Gentner’s fritillary may be more readily 

affected by this herbicide. Another study reported that risks to non-target plants associated with ALS-inhibitors 

are similar to those associated with other herbicides used at higher application rates (Obrigawitch et al. 1998).

Pests and Diseases (Sudden Oak Death)

Affected Environment

The action alternatives, Alternatives 3 through 5, would make herbicides available to the BLM in Oregon “to 

treat any vegetation, as necessary, to control pests and diseases in State-identified control areas, such as Sudden 

Oak Death (Phytophthora ramorum) in Southwest Oregon.” The pests and diseases in these cases are not plants 

that could be eradicated with herbicides, but fungi, insects, oomycetes, and other pests and diseases infecting or 

infesting native or other plants. Most of the time, such pests can be directly treated with fungicides, insecticides, 

and other pesticides or with non-pesticide methods. Occasionally, as in the case of Sudden Oak Death (currently 

infesting sites in southwestern Oregon), no effective direct control method is available and the best control 

available involves removing the host plant species. Such treatments would only be applied in those areas, and for 

those species, for which the Oregon State Department of Agriculture has specified a control area. Sudden Oak 

Death in Curry County is the only such area and species currently identified by the State for control.

In contrast, for example, BLM and other land managers sometimes remove Port-Orford-cedar from roadsides 

to help prevent the spread of Port-Orford-cedar root disease. This is not a State-identified control need, and the 

alternatives do not include herbicide use for such treatments.

Because Sudden Oak Death is the only currently known example of a treatment that would be proposed under this 

portion of these alternatives, a discussion of Sudden Oak Death is included here as both an example of, and as 
157

the foreseeable application of, this aspect of Alternatives 3, 4, and 5. Treatment of future infestations of different 

pathogens would require, at minimum, a determination of whether this or another EIS adequately addressed the 

potential effects of herbicides proposed for use, and would require appropriate site-specific analysis to address 

other aspects of the proposed treatment.

Sudden Oak Death Characteristics and Dispersal Strategy

Sudden Oak Death is caused by Phytophthora ramorum, a recently described, invasive pathogen of unknown 

origin (Rizzo et al. 2002, Ivors et al. 2004, Rizzo and Garbelotto 2003, Rizzo et al. 2005, Werres et al. 2001). 

Millions of oaks (Quercus spp.) and tanoaks have been killed by this pathogen in the forests and wildland urban 

interface of coastal California since the disease became evident in the mid 1990s (Meentemeyer et al. 2008). By 

2004, the disease had inundated the California coastline extending 750 km [466 miles] (Meentemeyer et al. 2004). 

The northern-most infestation in California is near Redway in southern Humboldt County. Sudden Oak Death 

was detected in Curry County in southwestern Oregon in 2001, where it was killing tanoak and infecting Pacific 

rhododendron and evergreen huckleberry (Goheen et al. 2002). The infestation remains contained to this one area 

of Oregon, although other strains of the pathogen were detected in, and eradicated from, approximately 60 Oregon 

nurseries between 2003 and 2007 (ENTRIX, Inc. 2008).

Often referred to as “fungi,” Phytophthora species are “water molds” that are closely related to marine algae 

(Erwin and Ribeiro 1996). Favored by moist conditions, Phytophthora species include some of the world’s 

most notorious plant pathogens. Most Phytophthora species are root pathogens; however, P. ramorum

predominantly affects aboveground plant parts such as leaves, needles, boles, green twigs, and woody stems 

(Davidson et al. 2003, Hansen et al. 2008). Over 100 plant species are known hosts including native forest 

species such as tanoak, oaks in the red oak group such as California black oak, Douglas-fir, coast redwood, Pacific 

rhododendron, evergreen huckleberry, and Pacific madrone as well as important commercial nursery species such 

as rhododendron, camellia, Pieris, and laurel (USDA, USDI 2008). In Oregon, the list of native plants that have 

been found infected in the wild is much shorter; tanoak, evergreen huckleberry and Pacific rhododendron are 

usually the only infected species; occasionally Oregon myrtle and Douglas-fir have been found infected in areas 

with high inoculum levels (Hansen et al. 2008).

P. ramorum is apparently well adapted to the mild, wet conditions of the Pacific Coast (Hansen et al. 2008). Its 

current distribution in California mirrors the range of coast redwood. In Oregon forests, the pathogen has only been 

detected within 10 miles of the Pacific Ocean in the Siskiyou Biome, where the climate is wet and mild in winter and 

warm and dry in summer with frequent fog. Oregon’s infested area falls within the Mixed-Evergreen Zone as defined 

by Franklin and Dyrness (1988). Tanoak, often with Douglas-fir, dominates the infested sites. Plant community 

associations are characteristic of the warm and wet environments of the Tanoak Series (Atzet et al. 1996).

The pathogen produces small sacs (sporangia) of swimming spores (zoospores) that readily break off and can 

be spread in rain splash, drip, stem flow, and wind. Multiple generations of spores may be produced during wet 

weather periods. It also makes thick-walled resting spores (chlamydospores) in infected plant parts that allow it to 

survive heat and drought and persist for months in soil and plant debris (Hansen et al. 2008).

In the forest, tanoak twigs and leaves are first infected in the upper crown. New growth in the spring is highly 

susceptible as are recently formed tanoak sprouts. Zoospores swim through water films on the surface of leaves 

or stems until they settle, germinate, and penetrate into the plant. New sporangia are formed on infected leaves 

and twigs in wet weather and may wash or splash down the stem. The trunk cankers that kill the tree apparently 

originate from spores washed down from above. Rhododendrons and huckleberries, and occasionally other hosts 

growing beneath or adjacent to infected trees, may be infected.

Final Environmental Impact Statement, Chapter 4: Pests and Diseases (Sudden Oak Death)
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Longer distance spread in forests is facilitated by turbulent transfer of sporangia dislodged from upper crown 

infections in clouds and wind-driven rain (Hansen et al. 2008). Most newly infected trees are found within about 

300 to 600 feet of previously infected trees, a pattern consistent with wind and rain dispersal. However, new 

disease sites have been detected up to 3 miles from nearest known infested areas. P. ramorum can also be moved 

over extreme long distances (continental, global scales) in infected nursery stock (Goheen et al. 2006).

Regulations and Control

P. ramorum is subject to both State (ORS 603-052-1230) and Federal (7 C.F.R. 301.92) quarantine regulations 

that restrict the human-assisted movement of hosts from infested areas into disease-free areas. Fourteen 

contiguous coastal counties in California are currently under quarantine. In Oregon, a 160 square mile area in and 

around the city of Brookings in Curry County, is currently subject to quarantine regulations.

Oregon State regulations also require eradication of the pathogen when it is found on State or private holdings. 

As a result, the Oregon Department of Agriculture and the Oregon Department of Forestry have been involved 

in an aggressive eradication program since 2001. The objective of the eradication program is to eliminate 

P. ramorum from all known sites and to prevent the pathogen from becoming established in native wildland 

forests by eliminating the pathogen or by eliminating the plants that carry the pathogen, at each newly detected 

infestation. This disease control program is not automatically enforced or applied to Federal lands. However, 

Federal land managers administering National Forests and BLM lands in Curry County recognize that success 

of the local P. ramorum eradication effort depends on the application of control treatments across the landscape 

without regard to land ownership, and have cooperated in this effort since 2001.

Treatment History in Oregon

When P. ramorum was first discovered in southwest Oregon forests in 2001, there were nine infested forest 

sites ranging in size from 0.5 to 11 acres and totaling 40 acres on non-industrial private forest lands, industrial 

private forest lands, and Federal forest land administered by the BLM. A nine-square mile quarantine area was 

established around the area of infestation. P. ramorum probably was present at one forest location as early as 

1998 (Hansen et al. 2008).

Initial eradication treatments involved cutting, piling, and burning infected plants and all nearby potentially 

infected or exposed host vegetation within a 50 to 100-foot radius buffer zone. Treatment monitoring revealed 

that the buffer area was inadequate to capture localized spread of the pathogen and that newly emerging sprouts 

from cut infested tanoaks were highly susceptible to infection and were maintaining the pathogen on infested 

sites (Hansen et al. 2008). A variety of methods to control tanoak sprouting were attempted including backpack 

spraying of new sprouts, manually cutting, piling, and burning new sprouts, and stump-top application of 

herbicides to prevent sprouting. The use of injected herbicides imazapyr or glyphosate to prevent sprouting of all 

tanoak stems one inch diameter and larger, where possible (on State, private, and National Forest lands), has been 

incorporated into the preferred treatment prescription since 2003. Buffer zone treatments have been increased and 

now include an area within a 300-foot radius of known infected plants or larger, depending upon the proximity 

to the quarantine boundary or other infected plants. Upon completion of tanoak removal and burning, most sites 

have been planted with non-host hardwood or conifer seedlings.

To date, over 730 tanoaks in Curry County have been found infected since 2001 on approximately 200 acres (Table 

4-8). Altogether, approximately 2300 acres, including approximately 200 acres of BLM land, have been treated 

(Kanaskie 2009). Since the first finding of Sudden Oak Death in Oregon in 2001, eradication of the disease has 

eliminated P. ramorum from some treatment areas, but it continues to appear in new locations in and near the 

regulated area in Curry County. In 2006 and 2007, the disease expanded considerably, probably due to consecutive 

years of unusually wet spring and early summer weather. Because of this expansion, Oregon’s Curry County 

quarantine area was increased to 160 square miles in January 2008. Disease levels were slightly reduced in 2008.
159

The net effect of the Oregon eradication program has been a dramatic reduction in the rate of disease spread as 

compared to similar areas in California where there is no comprehensive control program. Phytophthora ramorum

was detected at low levels in tanoak forests in southern Humboldt County, CA in 2001 and was subjected to similar 

environmental conditions, including moist spring and early summer weather in 2005 and 2006. In the four-year 

period from 2004-2007, the cumulative estimated infested area in Humboldt County grew from 123 acres to 

approximately 4,500 acres, an increase of 3,658 percent. By comparison, aggressive treatment in Oregon, while 

not completely controlling the pathogen, has substantially slowed disease progression. In Oregon in 2004, 70 

infested acres were detected; by 2007, this number had increased by 182 percent to 128 infested acres.

Environmental Consequences

Effects Common to All Alternatives

Like noxious weeds, negative environmental effects are predicted to result from both the spread of P. ramorum 

and its control treatments, with or without the use of herbicides.

Effects from the Spread of P. ramorum (Sudden Oak Death)

The spread of P. ramorum poses a potentially serious threat to forest ecosystem function, habitats, fire behavior, 

landscape aesthetics, and the horticultural and timber industries (Goheen et al. 2006, Rizzo and Garbelotto 2003, 

Appiah et al. 2004, Hansen et al. 2008). Rizzo and Garbelotto (2003) speculate that the “broad host range of P. 

ramorum, the variability of symptoms between different hosts, and the pathogen’s aerial dispersal suggest that it 

has the potential to cause a cascade of long-term landscape changes.” In the California counties where Sudden 

Oak Death was first discovered, the disease has already adversely affected ecosystem functions, increased fire and 

safety hazards and reduced property values in developed areas (Rizzo and Garbelotto 2003, Appiah et al. 2004).

Tanoak occurs on approximately 1 million acres in Oregon across four southwestern Counties (Curry, Coos, 

Douglas, and Josephine) with an estimated stocking of 81 trees per acre greater than 8 inches in diameter (FIA

data). Its deep taproot and lateral root configuration contribute substantially to slope stability. It is used by a 

variety of wildlife species for cover and forage. Its acorns are considered an important winter food for deer, 

bears, rodents and several bird species. Tanoak is also a substantial component of Nesting/Roosting/Foraging 

habitat used by northern spotted owls in Southwest Oregon (USDI 2008b). A small proportion of northern spotted 

owl nests in southwestern Oregon are in tanoak trees. A substantial reduction in the tanoak component due to 

Table 4-8. Sudden Oak Death in Oregon Forests

Year Number of tanoaks infected with P. 

ramorum

Number of new disease patches Area of new disease patches each 

year1 (acres)

2001 100+ 9 36

2002 85 12 8

2003 49 12 12

2004 30 9 10

2005 49 9 18

2006 143 36 40

2007 160 60 54

2008 122 63 23

1

 includes new infested sites and expansion of existing eradication sites

Final Environmental Impact Statement, Chapter 4: Pests and Diseases (Sudden Oak Death)
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P. ramorum-caused mortality would be expected to proportionally reduce the quality and quantity of tanoak 

dominated habitat and the abundance and availability of food items for the spotted owl. Tanoak, as well as other 

species affected by P. ramorum, including evergreen huckleberry, is also considered to be of cultural importance 

to American Indians with ties to coastal environments.

Increased spread to areas outside the current quarantine area will increase the size of the quarantine area itself. 

While tanoak is limited in range to southwest Oregon, other susceptible hosts such as Pacific rhododendron 

and evergreen huckleberry occur all along the Pacific Coast into British Columbia. Increased regulated area 

represents more restrictions on the flow of products and affects larger numbers and types of forest product users. 

Costs to affected industries include lost revenues associated with collecting and selling special forest products, 

increased manufacturing costs associated with debarking or kiln drying of logs, increased labor associated with 

removing soil and twigs from logs or other wood products, increased labor costs for sanitation measures, and costs 

associated with inspections and additional shipping documentation. Infested nurseries bear the cost of destroying 

infected plant materials and are not reimbursed for revenues lost. The implications, real or perceived, of the 

disruption and higher costs of doing business within a quarantine area can be far reaching and of international 

scope. Other countries often choose to regulate plant materials at the genus level, which would mean many 

non-host species have the potential to be regulated as well as the numerous species that are known hosts. Certain 

products may even be refused on the international market. There is also currently a perception among property 

owners that private property values are reduced inside quarantine areas.

Nursery stock represents nearly a billion dollar industry in Oregon and is the State’s most valuable agricultural 

commodity (ENTRIX, Inc. 2008). The 2,100 registered nursery and greenhouse grower operations in Oregon 

export out of State more than 75 percent of the nursery stock produced. The total economic impact of the nursery 

and greenhouse industry in Oregon in 2002 was estimated at $1.69 billion in output, $1.04 billion in value added, 

and 21,554 jobs. The first known detection of P. ramorum-infected nursery plants in Oregon occurred in 2003. 

Six infested nurseries were found that year. Since then, in the years 2004 to 2007, there have been an average 

of approximately 13.5 nurseries infected annually (COMTF). Federal rules enacted in 2004 and updated in 

2007 require P. ramorum inspections for all nurseries shipping out of State and specific testing procedures for 

nurseries with susceptible species or in a quarantine area. Potential losses to the nursery industry, including those 

associated with lost market share and reduced consumer confidence is estimated in the range of $28.16 million to 

$259.20 million per year.

Surveys for P. ramorum are underway in forests and nurseries in other parts of North America as well as 

throughout Europe. Risk assessments indicate that large areas of oak forests in the southern Appalachian region 

of eastern North America, as well as in oak and beech forests in Europe, are at high risk for the establishment of 

the pathogen and losses associated with subsequent mortality. Potential impacts of this pathogen to ecosystem 

health and function and to economics and trade go well beyond the oak and tanoak forests of the Pacific Coast.

Effects of Treatment

The effect of treatment are based on the site disturbance and clearing associated with treatment of the infested 

areas, including the effects of herbicides used in those treatments. The current treatments include: 1) glyphosate 

injection of tanoak on National Forest and imazapyr on private, to prevent resprouting, 2) cutting of infected host 

species (common examples are tanoak, rhododendron, and evergreen huckleberry) 3) creating a buffer area, and 

4) burning the cut vegetation (USDA, USDI 2008).

The zone of eradication includes all infected plants and those uninfected host plants in a buffer zone that extends 

out up to 300 feet from the infected plant(s). Host plant species to be treated would be determined based on host 
161

species affected at the site or information from recent research. Buffer zone delimitation is based on current 

understanding of short-distance spread of the pathogen (USDA, USDI 2008). Treatment areas beyond 300 feet 

would be applied on occasion to treat outlying infections found on the outer edge of the quarantine, if there is 

a need to increase the distance due to higher incidence of infections in that area, or monitoring shows a need to 

extend the treatment area. Treatment sites may also extend beyond the 300 feet to allow for logical treatment 

boundaries to accommodate falling of trees, adequate burning boundaries when broadcast burning, and ownership 

boundaries where the adjacent landowner has created a fuel hazard from their Sudden Oak Death treatment. 

Multiple infestations within close proximity to each other would be buffered by up to 300 feet to create a single 

treatment site. Treatment sites may be smaller than 300-feet extensions from infected plants when adjusted for 

natural breaks, changes in plant community, and topography. 

Effects (to Vegetation)21 by Alternative

Reference Analysis – No Herbicide Use and Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

With the exception of calendar year 2010, 22 control treatments would continue as they are now; herbicides would 

not be used on the BLM portion of the infestation. Imazapyr and glyphosate would continue to be used to kill 

tanoaks and prevent resprouting23 on the 90 percent of the control area that is not on BLM lands. Chainsaws and 

follow-up sprouting control would continue to be used to kill tanoak in the 10 percent of the control area on BLM 

lands. Because of the multicyclic nature of the pathogen, most sites are treated within 1 to 10 weeks of disease 

confirmation. However, newly emerging sprouts from cut tanoaks are highly susceptible to infection and are capable 

of maintaining the pathogen on infested sites. As such if they are not killed, the goal of eradicating the pathogen is 

not achieved. Maintenance of the pathogen on a given site increases the probability of spread to uninfested sites via 

natural or human-assisted means.

Monitoring data from early Sudden Oak Death eradication treatments in Oregon suggests that localized spread 

(the creation of new disease centers from nearby infected plants) will occur when the pathogen remains viable 

on a site. One to two new infection centers resulted from those sites where the pathogen was known to survive. 

Manual treatment of sprouts essentially delays treatment effectiveness when compared to herbicide treatment. 

Manual treatment of sprouts is not done for some time, perhaps as long as a year after cutting, because it takes this 

long for sprouts to develop to a stage where it is practical to treat them. Multiple treatments may be necessary if 

stumps subsequently resprout. Estimated contract costs for manual treatment of tanoak sprouts is $690/acre.

Treatments in Curry County that make use of herbicides are more effective at controlling the pathogen than the 

treatment currently used on BLM lands. It has been the opinion of pathologists that the approach currently used 

by BLM without herbicide use is 15 to 30 percent less effective than the herbicide approach. In 2008-2009, 

pathologists established 119 plots around the stumps of the known-infected tanoak trees that had been cut, and 

examined all host vegetation remaining on the sites. Six percent of the 106 plots on private lands had infected 

tanoak re-sprouts (post-treatment) using herbicide in some form (injected, stump-top application or sprout spray). 

Thirty-eight percent of 13 plots on BLM lands where herbicide was not used had infected tanoak re-sprouts 

(post-treatment). While the small non-herbicide sample size reduces the statistical strength of the apparent trend, 

the data nevertheless supports pathologist’s earlier impressions that herbicide use reduces the number of infected 

sprouts post treatment, thus reducing the potential for continued spread of the disease. 

Continuing to treat tanoak without herbicides on BLM lands can thus be expected to result in additional infestations, 

potentially several times more, than would occur using herbicides. These additional infested acres would be treated 

21 Other resource effects from Sudden Oak Death control are included in their respective effects sections in this Chapter.

22 The 1984/87 injunction preventing the use of herbicides on native species was amended June 22, 2009 to permit the use 

of glyphosate to kill tanoak to control Sudden Oak Death in calendar years 2009 and 2010. No herbicides were used by 

the BLM for this purpose in 2009, but they are proposed for 2010.

23 Tanoak is a notoriously vigorous resprouter, quickly regenerating multiple fast-growing stems from every cut stump.

Final Environmental Impact Statement, Chapter 4: Pests and Diseases (Sudden Oak Death)
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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by cutting and burning all infected tanoaks. The area that would be disturbed by control activities and the loss of 

tanoak would be expected to similarly increase for the indefinite future. The likelihood of totally eradicating the 

infestation from Oregon, which is the goal, is substantially less than under Alternatives 3 though 5.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases; 

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses; and, Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other 

Vegetation Management Objectives

The herbicides imazapyr and glyphosate would be available for use in killing tanoaks or other host species and/

or treating cut stumps to control P. ramorum on BLM lands. Other BLM-approved herbicides may be considered 

for use as Sudden Oak Death treatment methods evolve, or if future State-identified control areas involve different 

species. Under a proposed cooperative plan to step up efforts to eradicate the pathogen from Oregon, BLM 

treatments are estimated at 250 acres per year. Herbicide would be expected to be manually applied to frills 

chopped in the boles of tanoak trees, daubed or spot sprayed on cut stumps, and/or spot sprayed on sprouting 

foliage at cut stumps. If the infestation continues to spread, these acres would be expected to increase.

Herbicide treatments to prevent tanoak sprouting are more effective in eliminating P. ramorum from infested sites, 

because sporangia, zoospores, and/or chlamydospores remaining on site readily reinfect the sprouts and continue 

to occupy the site and reproduce. The estimated contract costs for injected herbicide treatment of tanoak stems is 

$300-600/acre.

Chainsaw control of sprouting stumps would be all but eliminated under these alternatives. Achieving the 

cooperating agencies’ goal of removing the pathogen from Oregon is far more likely; and all agencies would be 

expected to more aggressively fund and pursue that goal if it is made more achievable. Site disturbances from 

the falling, piling, and burning of tanoak would be similar to such disturbances under Alternative 2 (No Action). 

These disturbances would be less under these alternatives only to the degree that the acres in need of treatment 

would be less under these alternatives in the long term.

Measures to reduce the potential effects of herbicides on fish (see Fish Section): In July 2008, the BLM and Forest 

Service prepared a Programmatic Biological Assessment for submission to the National Marine Fisheries Service 

that described the potential for 2008-2013 control efforts to affect Federally Listed Coho and Chinook salmon 

within the Southwestern Oregon Province. That Biological Assessment determined the following treatments and 

protection measures would result in no effect to Federally Listed species.

“Where allowed and feasible, all tanoak (Lithocarpus densiflorus) and other hosts with stems meeting 

minimum requirements suitable for injection (approximately 1 inch in diameter and greater) within the 

eradication zone would be injected with the chemical aquatic-labeled glyphosate using a method referred to 

as “hack and squirt.” This method would employ a single tool that injects the herbicide directly into the stem 

with little to no chance for a spill. Once the tanoak is dead (approximately two weeks), it is cut. Only daily 

quantities of aquatic-labeled glyphosate would be transported to the project site. Aquatic-labeled glyphosate 

would not be applied if rain is likely to occur within 24 hours. Spill prevention, hauling, staging, mixing, 

loading, cleaning, application equipment, and storage requirements would be implemented.

“An Oregon Licensed applicator with forestry, aquatic, and right-of-way categories would be utilized. All herbicide 

mixing would be done in the presence of an agency Project Inspector. Equipment cleaning and storage and disposal 

containers would follow all applicable State and Federal laws. The licensed herbicide applicator would prepare 

a written herbicide Spill Contingency Plan in advance of the actual aquatic-labeled glyphosate application, then 

submit it to the Authorized Officer prior to operations, and keep a copy with each crew. An agency approved Spill 

Containment Kit would be on-site during all stages of applications” (USDA, USDI 2008:20).

These measures are consistent with the treatment expected under Alternatives 3-5.
163

Final Environmental Impact Statement, Chapter 4: Air Quality

Air Quality

Affected Environment

Because air pollution can directly pose health risks and cause significant welfare effects to humans, 

management and improvement of air quality in the U.S. is an important regulatory goal. The Clean Air Act, 

originally passed in 1955 and amended several times since, establishes a mandate to reduce emissions of 

specific pollutants via uniform Federal standards. Under the Act, the EPA identifies criteria pollutants, sets 

regulatory standards for those pollutants, and approves State and tribal implementation plans (SIPs and TIPs). 

States and tribes enforce the standards set by EPA and can delegate that authority to local air pollution control 

boards. States and tribes can set more stringent standards than the National Ambient Air Quality Standards 

(NAAQS) but cannot relax standards.

The EPA set primary and secondary NAAQS (Table 4-9). The primary NAAQS protect the health of susceptible 

individuals and the secondary NAAQS protect the general welfare of the public, including visibility in Class I 

areas (EPA 2007a). Different averaging periods are established for the criteria pollutants based on their potential 

health and welfare effects. The six pollutants currently regulated are sulfur dioxide (SO2), nitrogen dioxide (NO2), 

carbon monoxide (CO), ozone (O3), lead (Pb), and particulate matter (PM).

Particulate matter is a generic term for a broad class of chemically and physically diverse substances that exist 

as discrete particles over a wide range of sizes. For regulatory purposes, particulate matter is further classified 

by the particle’s aerodynamic diameter. PM10 includes all particulate matter with an aerodynamic diameter of 

10 microns or less and is referred to as inhalable PM. PM2.5 includes all particulate matter with an aerodynamic 

diameter of 2.5 microns or less, called fine PM, and is by definition a subset of PM10. Studies have shown more 

serious health effects associated with PM2.5; therefore, EPA promulgated more stringent standards for this class of 

particulate matter.

Table 4-9. Primary and Secondary National Ambient Air Quality Standards (NAAQS)

Criteria 

Pollutant Averaging Period

NAAQS

Primary Secondary

NO2 Annual 0.053 ppm 0.053 ppm

CO

1-hour 35 ppm ---

8-hour 9 ppm ---

PM10 24-Hour 150 μg/m3 150 μg/m3

PM2.5

24-hour 35 μg/m3 35 μg/m3

Annual 15 μg/m3 15 μg/m3

SO2

3-hour --- 0.5 ppm

24-hour 0.14 ppm ---

Annual 0.03 ppm ---

Lead

Quarter 1.5 μg/m3 1.5 μg/m3

Rolling 3-month Average 0.15 μg/m3 0.15 μg/m3

O3 8-hour 0.075 ppm 0.075 ppm
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 164

All areas of the nation have been classified based on their status with regard to attaining the NAAQS. The EPA 

designates an area as being in attainment for a criteria pollutant if ambient concentrations of that pollutant are 

below the NAAQS, or being in non-attainment if criteria pollutant concentrations violate the NAAQS. Once nonattainment areas comply with the NAAQS, they are designated as maintenance areas. Areas classified as nonattainment must implement a plan to reduce ambient concentrations below the NAAQS. Areas where insufficient 

data are available to determine attainment status are designated as unclassified, and are treated as attainment areas 

for regulatory purposes.

In general, the air quality in Oregon is good but with persistent problem areas where strong inversions tend to trap 

either CO or particulate matter at certain times of the year (Table 4-10). In mid-September 2008, EPA proposed 

listing Oakridge and Klamath Falls, Oregon and some of the area surrounding these two communities as nonattainment for PM2.5. No such listing had been made as of June 2010.

Table 4-10. Non-Attainment and Air Quality Maintenance Areas in Oregon

Pollutant Non-Attainment Maintenance

Ozone (8-hour standard) None Portland Metro – service district boundary

Salem – central transportation study area

CO Salem – central transportation study area

Grants Pass – central business district

Klamath Falls – urban growth boundary

Medford – urban growth boundary

Portland Metro – service district boundary

Eugene-Springfield – urban growth boundary

PM10

Eugene-Springfield – urban growth boundary

Oakridge – urban growth boundary

Grants Pass – urban growth boundary

Klamath Falls – urban growth boundary

Lakeview – urban growth boundary

Medford-Ashland – Rogue Valley

La Grande – urban growth boundary

Visibility Protection in Mandatory Federal Class I Areas

Visibility protection in mandatory Class I areas is the most significant aspect of the human welfare part of the 

Clean Air Act standards. The EPA promulgated the Regional Haze Rule in 1999 to further improve visibility in 

mandatory Federal Class I National Parks and Wilderness areas. Mandatory Class I areas include National Parks 

over 6000 acres in size and wilderness areas over 5000 acres in size that were in existence on August 7, 1977 plus 

any subsequent additions to those areas or any wilderness areas designated as Class I in their enabling legislation. 

All areas that have not been designated Class I are designated as Class II areas. Oregon has 12 mandatory Class I 

areas and potential to affect up to 5 mandatory Class I areas in adjoining states (Table 4-11). Oregon does not have 

any non-mandatory Class I areas nor are there any in close proximity to the Oregon border in surrounding states.

In all mandatory Class I areas, improvement in visibility must be made every 10 years for the 20 percent most 

impaired (haziest) days, regardless of current condition, and there must be no degradation for the 20 percent best 

(clearest) days, until the National visibility goal is reached in 2064. State and tribal implementation plans (SIPs 

and TIPs) outline how reasonable progress towards this goal will be achieved and demonstrated. Section 308 of 

the Regional Haze Rule provides nationally applicable provisions of the rule in the development of SIPs and TIPs.
165

Environmental Consequences

The PEIS estimated that up to 70,280 acres of BLM-managed lands may be treated with herbicides in Oregon 

annually24, and analyzed the resultant potential adverse effects from vehicle emissions and herbicide drift 

on air quality. That analysis made emissions estimates for carbon monoxide (CO), carbon dioxide (CO2), 

nitrogen oxides (NOx), total suspended particulates (TSP), particulate matter 10 microns and 2.5 microns in 

size (PM10 and PM2.5, respectively) and volatile organic compounds (VOCs). Lead, ozone and sulfur oxide 

emissions from herbicide use are very low and not included in the final analysis. Volatile organic compounds 

are substances emitted as gases from a variety of solid and liquid substances, including wildland fuels as they 

burn and herbicides. Effects are also described in terms of the Prevention of Significant Deterioration (PSD) 

criteria, although these criteria are intended for use on chronic point sources of pollution and not sporadic 

dispersed sources.

Although non-herbicide treatments were analyzed, these were not included in the PEIS, but were available as 

a supporting report to the PER Annual Emissions Inventory for BLM Vegetation Treatment Methods (ENSR 

2005a). This report also details the assumptions and analysis methods used. The emissions estimates include 

emissions from internal combustion engines used in both transportation and project implementation and 

fugitive dust from driving on unpaved roads and wind erosion. In Oregon, estimated total annual emissions 

in the PEIS included 5 tons of CO, 0.57 tons of NOx, 28.77 tons of TSP, 6.97 tons of PM10, 0.99 tons of PM2.5, 

and 0.34 tons of VOCs from treating 70,280 acres annually with herbicides. Carbon dioxide emissions from 

treating with herbicides are zero.

This air quality analysis builds on the analysis conducted for the PEIS. That analysis estimated emissions 

arising from prescribed burning; exhaust from ground vehicles used for transportation and operations, exhaust 

from chainsaws, and fugitive dust from driving on unpaved roads and from wind erosion off disturbed soils. 

Exhaust emissions did not include that from aircraft (fixed wing airplanes and helicopters). Fugitive dust 

emissions did not include that arising from actual treatment operations, such as dust kicked up by mowers and 

bulldozers/road bladers.

24 Alternative 5 (which is equivalent to the PEIS preferred alternative), estimated Oregon herbicide use at 50,000 acres 

per year. The Proposed Action (Alternative 4) would treat 45,000 acres annually.

Table 4-11. Mandatory Class I Areas in Oregon and Nearby in Adjoining States

State Class I Area Land Manager

Oregon

Mt. Hood Wilderness USDA Forest Service

Mt. Jefferson Wilderness USDA Forest Service

Mt. Washington Wilderness USDA Forest Service

Three Sisters Wilderness USDA Forest Service

Crater Lake National Park USDI National Park Service

Diamond Peak Wilderness USDA Forest Service

Kalmiopsis Wilderness USDA Forest Service

Mountain Lakes Wilderness USDA Forest Service

Gearhart Mountain Wilderness USDA Forest Service

Strawberry Mountain Wilderness USDA Forest Service

Eagle Cap Wilderness USDA Forest Service

Hells Canyon Wilderness USDA Forest Service

Washington Mt. Adams Wilderness USDA Forest Service

Goat Rocks Wilderness USDA Forest Service

Idaho Hells Canyon Wilderness USDA Forest Service

California Lava Beds Wilderness USDI National Park Service

Redwood National Park USDI National Park Service

Final Environmental Impact Statement, Chapter 4: Air Quality
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 166

Fugitive dust has not been included in any environmental analyses conducted to date in Oregon. In large part, this 

lack is because fugitive dust from roads or land management operations has not been identified as a significant 

concern or issue by members of the public, the EPA, or the Oregon Department of Environmental Quality. In 

large part, this lack of concern is because fugitive dust from driving on unpaved roads or from land management 

operations tends to remain in close proximity to the source. The distance particles are dispersed depends on 

both particle size, how high the particles are lofted, and wind speed. Most particles generated by soil are 10 

microns and larger and are not lofted more than a few feet, limiting their dispersion potential. Most road dust, for 

example, lands within about 10 feet of the road. (In contrast, most particles from prescribed fire are 2.5 microns 

and smaller and can be lofted hundreds to thousands of feet in the convection column, allowing for long distance 

and widespread dispersion of these particles).

At present, the only form of carbon emissions that is regulated is CO. The PEIS includes CO2 emissions as 

well from prescribed burning and from diesel exhaust. However, neither the PEIS nor this analysis includes a 

complete carbon budget. At present, the science is lacking to develop a complete carbon budget principally due 

to the lack of information on belowground carbon dynamics in all ecosystems and very limited information on 

aboveground carbon dynamics in rangeland ecosystems. Although carbon cannot be thoroughly analyzed, one 

of the known qualitative trade-offs are that activities that can restore healthy functioning ecosystems, including 

treatments to reduce invasive plants, tend to increase carbon sequestration (Verburg et al. 2004, Bradley et al. 

2006, Prater et al. 2006). This factor may be critical in rangeland ecosystems as conversion to annual grass 

dominance results in creation of a carbon source, while shrub-steppe vegetation is a carbon sink with more carbon 

stored below-ground than above.

All alternatives cover only the emissions from activities covered in this environmental analysis. Emissions from 

prescribed burning are the primary contributor to air quality concerns. Emissions from biocontrol, livestock and 

seeding or planting are negligible and not included. Since the analysis is based on emissions estimates used in 

the PEIS to maintain consistency and comparability, emissions from prescribed fire, mechanical, manual and 

herbicide operations include emissions from exhaust and fugitive dust. The emissions from exhaust and fugitive 

dust were included since it was not possible to remove these elements from the data provided in the PEIS and 

retaining the emissions would maintain comparability with the National estimates for Oregon.

The potential air quality effects of the alternatives in this analysis were determined by calculating the tons per acre 

emissions for PM10, PM2.5, CO, CO2, NOx, SO2, and VOCs from the selected alternative in the PEIS for prescribed 

fire, mechanical, manual, and herbicide treatments. Total suspended particulates were not included in this analysis 

as these differ very little from the PM10 estimates for smoke, the most significant contributor to particulate 

emissions. Lead was also not included as lead emissions were minor or zero for the various treatment methods. 

Total emissions by pollutant for each treatment method were divided by the acres in Alternative B of the PEIS (the 

selected alternative) to estimate the tons per acre of emissions. For prescribed fire, only the values from eastern 

Oregon were used as these included less smoldering combustion. This result was then multiplied by the estimated 

acres on Table 3-3 for prescribed fire, mechanical, manual and herbicide treatments in each alternative.

Effects Common to All Alternatives

Fugitive dust from driving on unpaved roads is not expected to measurably alter air quality in mandatory Class I 

areas or in air quality non-attainment or maintenance areas. The potential toxic effects of spray drift are covered 

elsewhere in this document. Effects to air quality from herbicide treatments are somewhat less than the National 

estimate as fewer acres are treated under all alternatives than were estimated in the PEIS. The highest emissions 

from manual treatments are CO, which largely comes from the exhaust of transportation vehicles, although 
167

manual emissions are minor relative to prescribed burning and mechanical treatments. All alternatives include a 

mix of treatment methods that are dispersed throughout the year, although lowest in winter, and across the entire 

State. Given this dispersion in time and space, it is not possible to determine if any alternative could result in a 

violation of NAAQS.

Prescribed burning, 80 to 97 percent of which would be in eastern Oregon in this analysis, would most likely take 

place in late summer or early fall so that the follow-up seeding would have the advantage of winter precipitation 

to enhance germination and establishment. Direct effects to air quality from burning annual grasses are of very 

short duration due to the lack of smoldering. Emissions are quickly dispersed and diluted, therefore, are not 

expected to impair visibility in any mandatory Class 1 areas. There is some potential for short-term (1-4 hours, 

depending on individual treatment unit size) adverse effects to the Klamath Falls and Lakeview air quality 

maintenance areas since both communities are located at or near the bottom of a basin where air flow out of the 

basin is restricted during inversions and on very cold days. Potential air quality effects will also be analyzed as 

part of project-specific environmental analysis and BLM policy requires that all prescribed fire burn plans address 

smoke management, regardless of location. Oregon State law prohibits the regulation of rangeland burning under 

the State smoke management rules; nonetheless, most BLM districts voluntarily comply with the Oregon Smoke 

Management Plan.

Table 4-12 summarizes the expected emissions by alternative; these estimates are based on those in the PEIS. 

Alternative 3 has the highest emissions of all pollutants. In comparison with statewide emissions for Oregon 

from 2002, the latest year for which data are available (EPA 2007d), the particulate emissions for Alternative 3 are 

0.2% of the 2002 statewide emissions. Carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), and 

Volatile Organic Compound (VOCs) emissions in Alternative 3 are <0.1% of 2002 statewide emissions. All other 

alternatives would result in fewer emissions. No statewide data are available for carbon dioxide, however, the 

relative proportion is likely similar to the criteria pollutants.

Table 4-12. Emissions from Vegetation Treatments

Emissions from herbicide treatment only

Pollutant

Total Emissions (tons)

Oregon 

Estimated from 

the PEIS

Reference 

Analysis

Alternative 2 (No 

Action)

Alternative 3 Alternative 4 

(Proposed Action)

Alternative 5

PM10 6.97 0 1.66 3.00 4.47 4.96

PM2.5 0.99 0 0.24 0.43 0.64 0.70

CO 5.00 0 1.11 2.02 3.00 3.33

NOx 0.57 0 0.13 0.23 0.34 0.38

VOCs 0.34 0 0.08 0.14 0.21 0.23

Emissions from prescribed fire, mechanical, and manual treatments1

Pollutant

Total Emissions (tons)

Reference 

Analysis

Alternative 2 (No 

Action)

Alternative 3 Alternative 4 

(Proposed Action)

Alternative 5

PM10 936.46 884.48 981.78 378.42 378.42

PM2.5 406.00 401.39 495.95 254.00 254.00

CO 509.46 757.04 1,635.59 1,633.50 1,633.50

CO2 12,312.90 18,660.42 40,392.59 40,058.75 40,058.75

NOx 33.13 42.62 79.12 70.12 70.12

SO2 6.99 10.22 21.47 20.87 20.87

VOCs 46.65 66.86 141.90 141.17 141.17

1 No estimates were included in the PEIS

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Effects by Alternative

Reference Analysis – No Herbicide Use

This strategy would have the highest emissions from mechanical treatments, the lowest from prescribed fire, 

and no emissions from herbicide treatments. Particulate emissions are the second highest of all the alternatives. 

Particulate emissions are highest in the mechanical treatments largely due to fugitive dust and diesel exhaust. CO 

and CO2 emissions are the lowest of all the alternatives. Prescribed burning is responsible for the bulk of the CO 

and CO2 emissions, although diesel emissions under mechanical treatments account for nearly 500 tons per year 

of CO2 emissions. Fewer acres are treated using prescribed fire than in the No Action Alternative (Alternative 

2) since prescribed fire for weed control is normally used in conjunction with some herbicide applications; if the 

herbicide is not used, there is no need to burn. Mechanical treatments partially replace some of the prescribed 

burning that would have occurred under the No Action Alternative.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Emissions from this alternative provide the main baseline against which the other alternatives are compared. 

Prescribed burning is the main source of CO, CO2, NOx, SO2, and VOC emissions. Mechanical treatments are 

the main source of PM10 and PM2.5 emissions, largely due to mechanical treatments of road rights-of-way and 

habitat improvement/ecosystem restoration treatments. Manual treatments and herbicide application result in few 

emissions of the pollutants analyzed. This level of emissions would continue if none of the action alternatives are 

selected.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

This alternative has the highest emissions of all pollutants analyzed. Under this alternative, the use of imazapic 

is expected to increase the use of prescribed fire by an estimated 6,800 acres. Prescribed fire would be used as 

preparation treatment, primarily in eastern Oregon, in a three-step treatment regimen for controlling invasive 

annual grasses. However, mechanical methods are still used to treat an estimated 9,300 acres of roadways and 

11,395 acres of other vegetation. As a result, emissions of particulate matter, CO and CO2 are the highest due to 

the large increase in prescribed burning and only minor decreases in mechanical treatments over the No Action 

Alternative (Alternative 2).

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

In this alternative, the number of acres treated using prescribed fire and manual methods are the same as 

in Alternative 3. However, the number of acres treated mechanically declines as herbicide treatments are 

substituted. As a result, the fugitive dust and exhaust-related emissions decline substantially, particularly PM10, 

PM2.5, and CO2 relative to the emissions in Alternative 3. The emissions of PM10 and PM2.5 in this alternative are 

the lowest of any of the alternatives. Carbon monoxide, CO2, NOx, SO2, and VOC emissions are only slightly less 

than Alternative 3, largely because prescribed fire is the primary source of these pollutants.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

The effects of Alternative 5 are very similar to Alternative 4 (Proposed Action). Emissions are increased 

slightly over Alternative 4 due to the inclusion of an additional 4,800 acres of herbicide treatments for habitat 

improvement/ecosystem restoration. Otherwise, emissions from prescribed fire, mechanical and manual methods 

are the same as Alternative 4.
169

Climate Trends, Projections, and Implications

See the Environmental Setting section at the beginning of this Chapter for information about the current climate.

Observed Climate Trends

Mote (2003b) documented many changes in the Pacific Northwest25 climate. Over the past 100 years, 

temperatures have increased but at slightly different rates. In the maritime climatic zone, which includes the 

coast, northwest Oregon and southwest Oregon in this study, average annual temperatures have increased 1.6° 

F while the central zone, which includes eastern Oregon, has seen average annual temperatures increase by 1.5° 

F. Increases have generally been higher at higher elevations. Temperatures have increased the most in winter 

(January-March) and least in fall (October-December), with temperatures also increasing substantially in summer 

(July-September) in the maritime climatic zone. The 1990s were the warmest decade in the 20th Century.

Precipitation has also increased, although much less so in the maritime climatic zone. This zone includes many 

stations that show little change or slight decreases in western Oregon. Unfortunately, the data for eastern Oregon 

includes only stations in the Blue Mountains and Columbia Basin and none in central or southern Oregon. 

Overall, precipitation has increased 2-4 inches. This amount is relatively insignificant along the Oregon coast 

and northwestern Oregon but highly significant in eastern Oregon. Most of this increase occurred before 1945. 

Spring (April-June) precipitation has increased the most across the Pacific Northwest. Summer precipitation 

has increased some 70 percent in the central climatic zone, but this increase is insignificant given that summer 

precipitation is already very low in this zone.

These observed changes in precipitation and temperature are beginning to manifest in other aspects of Oregon’s 

climate. Below 5900 feet elevation, the amount of snow on April 1, typically the peak of snow accumulation, 

has declined by as much as 60 percent since 1950, coinciding with increased temperatures and despite increased 

precipitation (Mote 2003a). Less winter precipitation is falling as snow in the Cascades and Blue Mountains 

(Knowles et al. 2006) and spring snowmelt is occurring earlier (Westerling et al. 2006). Aridity in the interior 

western United States, which includes eastern Oregon, has been increasing since 1900 (Cook et al. 2004). On a 

global basis, the number of cold days, cold nights, and frost have become less frequent while the number of hot 

days, hot nights, and heat waves have become more frequent (IPCC 2007), although these trends have not been 

analyzed specifically for Oregon.

Climate Change Projections

The Climate Impacts Group (CIG) (2008) at the University of Washington recently released the latest projections 

for the climate of the Pacific Northwest. This forecast is based on 20 general circulation models and on two 

emissions scenarios – B1 (lower emissions) and A1B (higher emissions). By 2100, CO2 concentrations are 

expected to range from 549 ppm under the B1 scenario to 970 ppm under the A1B scenario. These concentrations 

would be approximately 2 to 3.5 times, respectively, the pre-industrial CO2 concentration of 280 ppm. Projections 

for the resulting impact on temperature have greater certainty than for precipitation.

In general, the climate in Oregon will be warmer, but not significantly wetter. Temperatures are expected to warm 

by 0.5° F per decade into the 2050s, with future changes depending on the emissions scenario used. Average 

annual temperature will increase 2.2° F (1.1-3.4° F) by the 2020s, by 3.5° F (1.6-5.2° F) by the 2040s and by 5.9° 

F (2.8-9.7° F) by the 2080s relative to the 1961-1990 average. As early as the 2020s this change could be outside 

25 The Pacific Northwest (in this instance) is defined as all of Oregon, Washington, and Idaho, southern and central British 

Columbia and part of western Montana.

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the range of variability observed in the 20th Century. All seasons will be warmer with the largest temperature 

increase in summer (June-August).

Only small changes in precipitation are expected. The average annual precipitation could increase only 1-2 

percent (-10 percent - +20 percent). By the 2020s, winter (December-February) precipitation may increase, 

although it is more likely to increase by the 2080s. Summer precipitation is expected to decrease.

Hydrological drought is expected to become more common due to increased temperatures and decreased 

snowpack. The Aleutian Low and storm track across the North Pacific are expected to shift north and intensify, 

likely increasing the frequency of large-scale storms and bringing more intense precipitation into the Pacific 

Northwest in winter (Leung et al. 2004, Salathé 2006). Most of this intense precipitation will fall in western 

Oregon and the Blue Mountains and most of the change is expected to occur in the second half of the 21st century 

(Salathé 2006).

These projected trends in temperature and precipitation have implications for other aspects of climate as well. 

The observed trend for less snow in winter and earlier snowmelt will likely continue. Increasing temperatures 

indicate the transient snow zone will rise in elevation and potentially all but the highest peaks in the Cascades 

could fall within this snow zone (Leung et al. 2004). The growing season will likely shift to earlier in the year, 

although it is much less clear if the length of the growing season will increase, decrease or remain unchanged. 

The length and intensity of the summer seasonal drought will likely increase. Cold snaps will likely happen less 

often, although they may be just as severe as past cold snaps given the source of the cold air. Heat waves and 

hot extremes are very likely to become more frequent (IPCC 2007). Multi-year droughts are expected to become 

more frequent and last longer (Cook et al. 2004). Summer may have more clear days (Leung et al. 2004).

These projections include a number of uncertainties. Generally, regional climate models can produce very 

different results from general climate models, even though the general climate models form the basis for the 

regional models. The differences arise from the generation of general climate model used as a basis, differences 

in model parameterization and differences in model resolution (Christensen et al. 2007). Ensemble modeling and 

forecasts can help reduce some of this source of uncertainty (Leung et al. 2004). High elevation terrain is not well 

represented in most models, potentially leading to an underestimation of warming at higher elevations associated 

with snow-albedo feedback (Christensen et al. 2007). How changing ocean conditions will affect ENSO and 

PDO remains unknown (Christensen et al. 2007, CIG 2008). Current models have not yet incorporated new 

information on the accelerating rate of atmospheric CO2 growth (Canadell et al. 2007). Other events, such as 

the Asian dust storms, have only recently been identified as potentially impacting the climate of western North 

America (Zhang et al. 2007) so have not been adequately incorporated into climate models either.

The alternatives themselves could affect climate change, but the differences between the alternatives are slight 

and potentially speculative. As noted in the Air Quality section, the science is lacking to develop a complete 

carbon budget principally due to the lack of information on belowground carbon dynamics in all ecosystems and 

very limited information on aboveground carbon dynamics in rangeland ecosystems. Although carbon cannot be 

thoroughly analyzed, one of the known qualitative trade-offs are that activities that can restore healthy functioning 

ecosystems, including treatments to reduce invasive plants, tend to increase carbon sequestration. That section 

points out that Alternative 4 (Proposed Action)’s replacement of roadside mowing with herbicide use should 

decrease fossil fuel use. These factors point to the Proposed Action having favorable effects on climate change 

and long-term air quality when compared to the No Action Alternative (Alternative 2), but the difference is 

qualitative and likely so small as to play little role in influencing the choice between the alternatives.
171

Implications of Climate Change on Invasive Plants

In response to increased temperatures, longer hotter summers, earlier snowmelt, and resultant increased 

hydrologic droughts, plants will migrate north and upslope (Tausch 2008, Middleton 2006). Existing plant 

communities likely will disappear and new plant communities will form based on differential migration rates; 

differential responses to temperature, precipitation and increasing carbon dioxide (CO2); and differential responses 

to competition (Best et al. 2007, CIG 2004:4). Changing weather patterns and the resultant shifts in plant 

communities will both favor invasive plants.

Many invasive plants originate from Mediterranean climates,26 and have wide ecological amplitudes, two features 

that make them successful in Oregon and will make them more successful in the future. For example, many 

invasive plants are more likely than native plants to have a deep taproot, sparse foliage, or other characteristics 

for surviving long hydrologic droughts.27 Some species may respond more to temperature changes, some more to 

precipitation changes, and some to the joint change in temperature and precipitation (CIG 2008).

There is also evidence that rising CO2 can preferentially select for invasive plant communities (Ziska and George 

2004:427, Patterson 1995). The rise in CO2 increases photosynthesis, for a “fertilizer effect.” Ziska and George 

(2004:436) found doubling CO2 increased biomass 34 percent if moisture, nutrients, and light were not limiting. 

One of the common responses to rising CO2 is an increase in belowground root growth relative to aboveground 

shoot growth (Ziska and George 2004:439). Thus, the CO2 fertilizer effect favors plants with a taproot, or higher 

root/shoot ratio than other plants, both of which are often characteristic of invasive plants.

High CO2 has altered weed herbicide resistance: Canada thistle (a species that reproduces asexually from 

belowground organs) grown at high CO2 levels becomes resistant to glyphosate (Ziska et al. 2004). If high CO2

affects other weeds similarly (increases herbicide resistance while enhancing belowground biomass storage), 

those species will become increasingly competitive with native species and harder to kill, resulting in changes to 

communities, and thus ecosystem process.

General warming and a decreased incidence of killing frosts will allow the spread of invasive plants currently 

limited by a low tolerance to freezing. Warming will allow additional invasive plants to enter Oregon.

The shift in plant communities upslope and to the north is essentially a disturbance that makes an increasing 

number of niches available. The same characteristics that make invasive plants successful at invading other 

disturbances will likely give invasive plants an advantage during this migration.

Other factors will exacerbate this “disturbance”: increased fire frequency and intensity; anthropogenic 

disturbances; and severe weather disturbances. For example, climate shifts will cause fuel loads to accumulate 

and dry earlier in the growing season (not counting the increased loading from drought-related mortality). 

Research suggests some weeds including cheatgrass grown at higher CO2 levels burns hotter, not just because 

of additional carbon storage, but also because of a higher carbon ratio (Blank et al. 2006). Thus wildfires in 

cheatgrass and potentially other invasive plant-filled communities would be expected to burn hotter in the future, 

all else being equal. Hotter wildfires are more likely to remove even fire-resistant native plants, and then invasive 

plants are more likely to invade the resultant burned areas (USDA 2005a:3-21).

Anthropogenic disturbances will have the same effect, contributing to the disturbance and stress caused by the 

climate shift and creating more opportunities for invasive plants. Similarly, as native plants thin and soils become 

26 A type of climate characterized by hot, dry, sunny summers and a winter rainy season.

27 Long seasonal soil moisture decreases resulting from earlier snowmelt and longer, hotter dry seasons.

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poorly protected, increased storm intensities are more likely to disturb soils. For each disturbance, climate 

shifts may have decreased the ability of local native plants to compete with invasive ones, or even to be used in 

subsequent restoration. It is not clear, however, if disturbances will compound the effects of climate change or 

simply trigger them.

Site-specific changes may be quite different than described above. However, a general conclusion, based on 

the preponderance of current literature, suggests, “most of the important elements of global change are likely 

to increase the prevalence of biological invaders” (Dukes and Mooney 1999:138). The temperature and CO2

changes predicted for Oregon in the coming decades will increase the spread of invasive plants and, to some 

degree make them harder to control. Plants already geographically restricted and/or stressed, such as those rare 

species listed under the Endangered Species Act or otherwise included in the Special Status species Program, will 

become more vulnerable to invasive plants than they are today, because of climate change. This increased level of 

risk is in addition to the risk that will result as invasive plants occupy more acres in Oregon.

Effects of the Alternatives on Climate Change: Greenhouse Gas Emissions and 

Carbon Storage

As well as resulting in the emissions of greenhouse gasses (see Air Quality), the alternatives also have potential 

implications to climate change. While the effects of any one action or even a group of actions may be very 

small, climate change is being driven by the cumulative impacts of the sheer number of very small actions. For 

example, while a single motor vehicle contributes a negligible amount of greenhouse gases compared to the 

volume of the atmosphere, the cumulative effects of millions of motor vehicles over several decades has been 

substantial (IPCC 2007).

Cumulative effects from the alternatives arise from two different primary effects: 1) the greenhouse gases emitted 

in conjunction with the types of treatments and numbers of acres treated and 2) the impact the treatments have on 

the plant communities treated and their carbon budgets. The feedback link between vegetation and climate has 

long been recognized, although the current generation of general circulation models (GCMs) and dynamic general 

vegetation models (DGVMs) lack the capability to include this feedback much below the biome level (e.g., 

conifer forest, grassland, etc.)(Neilson 1995, Bachelet et al. 2001, Sitch et al. 2003, Woodward and Lomas 2004, 

IPCC 2007).

Table 4-12 (Emissions from Vegetation Treatments) in the Air Quality section discloses the estimates of carbon 

monoxide and carbon dioxide from the different mix of treatment methods and acres treated in each alternative. 

The remainder of this discussion focuses on the implications for carbon storage as a factor in climate change.

Both carbon storage and carbon emissions are a function of the total biomass on a given site, and the difference 

between gains from photosynthesis and losses from respiration, or net ecosystem exchange (NEE) (IPCC 2007). 

By altering the species’ composition and total biomass on a site, the alternatives can affect whether NEE is 

positive or negative and over what time scales. Another cumulative impact is whether any shifts in species’ 

composition increase or decrease resistance to or resilience from another disturbance that can also affect NEE 

over the short- or long-term (Obrist et al. 2003, Prater et al. 2006, IPCC 2007). The highest carbon storage 

capacity occurs in forests, followed by juniper woodlands, sagebrush-steppe, salt desert shrub, and annual 

grasslands. Biological soil crusts can be a significant factor in the carbon fixing capability of some juniper 

woodlands, sagebrush-steppe and salt desert shrub (Eldridge 2000, Belnap 2003, Housman et al. 2006) but annual 

grasslands typically have no biological soil crusts due to the frequency of fire (Belnap 2003, Hilty et al. 2004, 

Housman et al. 2006).
173

Carbon-flux studies in both forests and sagebrush-steppe indicate that both systems are net emitters of carbon in 

dry years (carbon sources) and net storers of carbon in wet years (carbon sinks) with forests usually functioning as 

carbon sinks in average years as well (Obrist et al. 2003, Hunt et al. 2004, Prater et al. 2006, Wharton et al. 2009). 

Invasive annual grasslands are carbon sources (Obrist et al. 2003, Prater et al. 2006).

By convention, carbon is assumed to comprise about 50% of the total biomass of any given plant. At present, 

there are few reliable estimates of the total biomass of any biome, plant community, or plant species. The most 

reliable estimates are for the aboveground portion of commercially important conifer species and the least reliable 

estimates are for belowground storage, shrubs, herbaceous plants, and biological soil crusts. Alternatives that 

maintain or increase the the extent of late-successional biological soil crusts or control or reduce invasive plants, 

maintain or enhance net carbon storage capacity on BLM-managed lands. Alternatives that reduce the extent of 

late-successional biological soil crusts or permit invasive plants to spread reduce net carbon storage capacity on 

BLM-managed lands.

In most cases, whether biomass and overall carbon storage capacity is increased, maintained, or decreased through 

the use of herbicides is not known due to the lack of data that would allow comparisons between the biomass 

on a site dominated by an invasive or unwanted plant verses a site dominated by a native plant community. 

For example, knapweeds and thistles are typically taller than most native tall bunchgrasses, such as bluebunch 

wheatgrass, and therefore may contain more aboveground carbon. Those species that are taprooted likely contain 

less carbon belowground than a tall bunchgrass, but it is much less clear if rhizomatous species contain more, less, 

or about the same belowground carbon as a tall bunchgrass. The amount of both above and belowground carbon 

in a stand of reed canarygrass may well be very similar to a stand of cattails but may be greater than mixed stands 

of cattails, reeds, and sedges. The few cases where this information is known with a higher degree of confidence 

are discussed below.

Invasive annual grasses support less biomass both above and belowground than the native grasses and woody 

plants they displace. Invasive annual grasslands are most common in eastern Oregon but can be found in western 

Oregon as well. Alternative 2 (and the Reference Analysis) would allow invasive annual grasses to continue 

spreading at or nearly their full biological potential, reducing the carbon storage capability on BLM-managed 

lands with the greatest effect in eastern Oregon. Carbon emissions from the respiration of soil organisms would 

increase until the carbon previously stored belowground by the native plant community is mineralized (Obrist 

et al. 2003, Norton et al. 2004, Bradley et al. 2006, Prater et al. 2006). The availability of herbicides effective 

on these invasive annual grasses under Alternatives 3 through 5 would slow the rate of loss to invasive annual 

grasslands. Overall carbon storage capacity would continue to decline, but at a slower rate than under the 

Reference Analysis and Alternative 2 (No Action).

Juniper woodlands store more carbon aboveground than sagebrush-steppe. The differences in belowground 

storage are less clear due to differences in root types, total root mass and root turnover rates. As western juniper 

canopy cover increases, sagebrush and other shrub biomass decreases (Miller et al. 2005). On sites with a 

restrictive soil layer close to the surface, grass and forb biomass also decrease as western juniper canopy cover 

increases (Miller et al. 2005). In such locations, surface erosion also tends to increase, removing biological soil 

crusts and carbon stored in soil layers as the top layer of soil is lost. The effect of reducing western juniper on 

carbon storage capability is uncertain but may be neutral on sites with a restrictive layer close to the surface and 

reduced on other sites. Under the Reference Analysis and Alternatives 2 and 3, western juniper expansion would 

continue as long as the climate remains favorable for this species with an overall increase in aboveground carbon 

storage. There would also be increased erosion risks on sites with a restrictive soil layer close to the surface. 

Under Alternatives 4 and 5, some treatments are intended to reduce western juniper resulting in a decrease in 

carbon storage capability and maintenance of existing erosion risks.

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Himalayan blackberry, which is a semi-woody invasive plant commonly found in western Oregon, contains more 

aboveground biomass and carbon than the grasses and forbs it displaces in grasslands, savannahs and open forests. 

Aboveground carbon storage would be enhanced where Himalayan blackberry is allowed to continue spreading 

at its full biological potential. Alternatives 2 through 5 could potentially reduce carbon storage capability to the 

degree they are used to reduce the extent of Himalayan blackberry west of the Cascades. However, since some 

blackberry controls are already available under Alternative 2 (No Action), the amount of blackberry control is not 

expected to vary significantly between the alternatives.

Along with the general lack of detailed information concerning existing carbon storage and storage capability is 

the fact that climate responses to changes in greenhouse gas emission and storage rates is nonlinear (IPCC 2007) 

making any assessment of potential effects of the alternatives on climate itself largely speculative.

Soil Resources

Affected Environment

Soil is a dynamic medium consisting of varying levels of sand, silt and clay particles, organic matter, and 

soil organisms, both large and small (e.g., earthworms, bacteria and fungi). Soil functions to hold nitrogen, 

phosphorus, and herbicides in place, keep them out of surface water, and deliver nutrients and water to plants, 

as they need them. Soil filters, buffers, degrades, immobilizes, and detoxifies organic and inorganic materials, 

including herbicides, other manufactured products, and materials from atmospheric deposition (USDA 1997).

Soil texture (the proportional amount of sand, silt, and clay constituents) and organic matter affect the movement 

of water and herbicides into and through a given soil. Coarser textured soils (those with high amounts of sand) 

allow faster movement of water into and through them compared to fine textured (clay) soils. Clay textured soils 

have higher rates of surface runoff than sandy soils. Silty or clay textured soils and those with high levels of 

organic matter have greater surface areas that can absorb and hold greater amounts of herbicides when compared 

to coarse textured soils. Organic matter and clay particles have different positive and negative charges (cation 

exchange capacity, CEC) that provide the adsorbing mechanism. The bond between the herbicide and particle can 

be lost if other mechanisms within the soil are great enough to break the bond.

The USDA National Resources Conservation Service (NRCS) differentiates soils by diagnostic horizons28 (layers) 

or features that reflect soil-forming processes. On BLM lands in Oregon, there are four major and five minor 

soil orders (Figure 4-4). Each of the biomes may contain several or all of the soil orders because of various 

combinations of local soil forming factors. The four major soil orders (based on abundance in Oregon) are:29

Aridisols are soils found east of the Cascades (primarily in the Sagebrush Steppe biome) that have developed 

under low moisture regimes. Above ground vegetation is sparse; thus organic matter accumulations are low (less 

than 2 percent), and the ability of these soils to filter, store and process herbicides is limited to the upper soil 

layers. Herbicide degradation by sunlight (photo degradation) would be high but biological degradation would be 

low unless adequate moisture for processing by organisms was present.

28 Soil horizons, ordered from top to bottom include: the O horizon (organic matter); the A horizon (surface soil); the B 

horizon (subsoil); and, the C horizon (substratum).

29 Soil Order information for State of Oregon summarized from USDA (1999) and USDA (2006a). Major/minor split 

based simply on abundance on BLM lands in Oregon.
175

Figure 4-4. 

Soil

Orders

Final Environmental Impact Statement, Chapter 4: Soil Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 176

Mollisols are productive soils rich in organic matter from the dense root systems of prairie grasses. They cover 

much of the Eastern Forest and Sagebrush Steppe biomes and are found in the Willamette Valley and Southern 

Siskiyou Mountains. Their origin from windblown or weathered basalt parent materials allows some to be prone 

to wind erosion if not stabilized by growing vegetation. Their high organic matter content (Table 4-13) binds 

herbicides and provides degradation by soil organisms, helping reduce the risk of groundwater contamination.

Inceptisols are generally young mineral soils with high infiltration rates and low amounts of clay. Herbicide 

transport to lower depths of soil and groundwater or streams would occur if it were not already tied to vegetation 

or organic matter at the surface. They often support coniferous and deciduous forests as well as rangeland 

vegetation, and are found primarily in the Western Forest and Willamette Valley biomes with a small percentage 

in the Siskiyou biome.

Entisols occur in areas of recently deposited parent materials or in areas where erosion or deposition rates are 

faster than the rate of soil development, such as dunes, steep slopes, and flood plains. These soils are sandy in all 

layers, and are subject to wind erosion if vegetation is lacking. Most occur east of the Cascades.

The five minor (less abundant) Soil Orders are:

Ultisols support forest vegetation in the Willamette Valley and Siskiyou Biomes. They have properties that allow 

processing and storage of herbicides such as high amounts of clay, organic matter, and good drainage.

Andisols formed on volcanic ejecta and have a high natural productivity. They are prominent in the Cascades with 

minor occurrence in the Blue Mountains. The ability of these soils to process (that is, to bind, degrade, and store) 

herbicides is high, as moisture, plant growth, and binding sites would be high in the silt portion of most soils.

Vertisols have high clay content, pronounced changes in volume with moisture changes, cracks that open and 

close periodically, and evidence of soil movement. Vertisols are problematic for herbicide application due to the 

cracking and movement, but may bind herbicides due to high clay contents.

Alfisols are developed in semiarid to moist areas where weathering has leached clay minerals and other constituents 

out of the surface layer and into the subsoil, where they can hold and supply moisture and nutrients to plants.

Spodosols are soils with a B (subsoil) horizon consisting of an accumulation of black or reddish materials 

that have a high CEC, important for binding herbicides within the soil. These sandy soils have good drainage 

properties along with high organic matter contents that tend to bind and process herbicides well. These are found 

primarily on the forested coastal lands and beach areas of the BLM west of the Cascades. They are also the prime 

areas for growing cranberries on the coast.

Organic Matter - On any soil, the amount of organic matter is key to maintaining structure, allowing water and air 

to infiltrate to low depths, and providing a source of energy to microbial communities. Many herbicides readily 

bind to organic matter. Organic matter levels greater than 2.5 to 3 percent may tie up soil-applied herbicides prior 

to them being delivered to the plant. Some labels recommend increasing the amount of herbicide to the maximum 

rate in these situations. Soil orders found in the west side of the State, such as Inceptisols, Spodosols and Ultisols, 

contain considerably more organic matter than the Mollisols or Aridisols of the east side.

Clay has more surface area per volume and provides binding sites for herbicides and water, supporting herbicide 

breakdown by microorganisms (see below). However, as the percentage of clay in a given soil increases the 

potential for compaction and increased runoff also increases. If the soil becomes nearly all clay, as in the case of 
177

Vertisols, seasonal drying and wetting can produce wide deep cracks in the soil and herbicides can end up going 

deep into the soil and not necessarily on the weeds they are intended to remove.

Erosion Risk - Soils are rated by NRCS for a tolerable amount of loss before productivity is reduced. For 

example, Aridisols and Mollisols can lose less than 3 tons of soil per acre per year before their long-term 

productivity would be reduced (see T-Factor, Table 4-13). These soils also have low average wind erosion group 

ratings (5.6 to 6.5 ) if 70 percent or more of their surface becomes exposed. Since many invasive weeds provide 

poor soil cover, and weed treatments (particularly prescribed fire or the use of persistent pre-emergent herbicides) 

can leave soils exposed greater than a 70 percent level, the NRCS rating provides an indicator of certain types 

of risks. In addition to the potential for productivity loss through wind or raindrop erosion, erosion can move 

herbicides off site if they are attached to soil particles.

Biological Crusts provide important functions within, and on the surface of, the soil, such as improving soil 

stability and reducing erosion, fixing atmospheric nitrogen, and contributing nutrients for plants. Crusts are made 

up of organisms living at the surface of soils in semiarid and arid environments such as those in the Sagebrush 

Steppe and Eastern Forest biomes. The major components of the crust are cyanobacteria, green algae, microfungi, 

mosses, liverworts, and lichens. These crusts can cover up to 70 percent of the soil spaces not occupied by 

Table 4-13. Soil Order Properties and Extent on BLM Lands

Soil Order

Estimated 

Acres on 

BLM Lands

(% of total)

Average 

Percent 

Organic 

Matter1

Average 

Percent Clay1

Average T 

Factor2

(Tons/Ac/Yr 

of Soil Loss 

Allowed)

Average 

Wind Erosion 

Group Rating

(1= High, 

8=Low 3)

Range { }

Average 

Water 

Erosion 

Risk Rating

K Factor4

(L<M<H)

Average pH 

value (range)

Major Orders

Aridisols 6,913,000 

(43.9) 1.67 18.2 2.7 (1-5) 5.59 {1-8} .31 (M) 7.47 (6.8 – 8.5)

Mollisols 5,051,000 

(32.1) 2.92 21.0 2.9 (1-5) 6.46 {1-8} .25 (M) 6.86 (5.4 – 9.0)

Inceptisols 1,401,000 

(8.9) 6.14 21.7 3.0 (2-5) 6.8 {4.1-8} .22 (M) 5.88 (4.5 – 8.8)

Entisols 1,055,000 

(6.7) 2.23 18.5 4.4 (2-5) 4.95 {3-8} .31 (M) 7.63 (5.1 – 9.0)

Minor Orders

Ultisols 523,000 (3.3) 4.68 27.7 3.5 (2-5) 6.88 {6-8} .26 (M) 5.66 (5.4 – 6.4)

Andisols 297,000 (1.9) 6.04 16.9 3.0 (2-5) 5.69 {2-7} .22 (M) 5.72 (4.4 – 7.3)

Vertisols 181,000 (1.1) 5.62 34.1 4.6 (2-5) 7.68 {6-8} .23 (M) 7.05 (6.5 – 7.6)

Alfisols 66,000 (0.4) 3.37 15.6 3.3 (3-5) 4.85 {3-7} .18 (L) 6.02 (5.9 – 7.0)

Spodosols 12,000 (0.1) 7.28 14.8 4.8 (3-5) 6.2 {6-8} .30 (M) 5.06 (5.0 – 5.2)

Unknown 233,000 (1.5) -- -- -- -- -- 1 Average Organic Material and Clay contents derived from A horizon for all soils within the order, not the entire profile

2 T Factor: Tolerable amount of soil loss (tons per acre per year) prior to reduced productivity

3 Wind Erosion Groups rate the tons per acre soil loss potential for wind erosion on 70 percent-plus unvegetated soil. Ratings are: 1 = 160-

310 per tons/acre/year; 2 = 134 tons; 3 and 4= 86 tons; 5 = 56 tons, 6 = 48 tons; 7 = 38 tons; and, 8=0 tons (USDA 1999) 4 K Factor Erosion Risk Rating: Low- .05 to .2, Med .21 to .40, Hi .41+. Erosion factor K appears in the Universal Soil Loss Equation 

(Wischmeier and Smith 1978) as a relative index of susceptibility of bare cultivated soil to particle detachment and transport by rainfall.

(Data derived from USDA 2009a) 

Final Environmental Impact Statement, Chapter 4: Soil Resources
 178

Vegetation Treatments Using Herbicides on BLM Lands in Oregon

vascular plants in arid regions. The Aridisols have this important soil covering and protection mechanism. 

Individual components of the crusts become reduced during herbicide applications thus the crusts lose some 

ability to function as a soil protection and a nutrient cycling mechanism. 

Macro and Microorganisms are extremely important to proper functioning soil processes. Fungi and bacteria 

microorganisms convert complex organic compounds (including herbicides) into simpler ones that can be used 

by other plants and organisms for growth. The macro-organisms such as insects, worms, arthropods, and even 

burrowing animals mix the upper organic matter into the lower soil level for processing by the microorganisms 

found between soil particles. Soil temperature, moisture levels, and type of vegetation all affect the presence and 

activity of soil organisms (USDA 2004).

Environmental Consequences

Soil has the capacity to filter, buffer, degrade, immobilize, and detoxify herbicides. Soil properties that 

specifically bind herbicides or water to surfaces of the soil or organic matter are crucial to the soil’s ability to 

detoxify herbicides. The three most important soil properties are soil clay content, organic matter content, and 

the acidic or alkaline nature (pH) of the soil. These govern the ability of a soil to provide an environment for 

organisms and water to filter, buffer, degrade, or otherwise store or breakdown the various herbicides. Changes to 

soil properties because of non-herbicide or herbicide treatments, or noxious weeds, is considered an adverse effect 

on soil function. 

Effects Common to All Alternatives

Biological Crusts: Disturbance of soil crusts results in decreased soil organism diversity, nutrient cycling, soil 

stability, and organic matter. Crust disturbance can come about through trampling, fire, or burial by windblown 

soil. Invasive weeds generally establish themselves on the areas where crusts have been broken and soil is 

exposed, either by mechanical or animal disturbance or possibly an erosional event that buries them. It is possible 

that some30 herbicides could reduce the individual components of the crust and thus affect their ability to function 

as soil protection and cycling mechanisms.

Macro and Microorganisms: Herbicides probably affect few soil organisms directly (USDA 2004). However, 

there is only limited research on the toxicity of many herbicides to most soil organisms. Of the 18 herbicides 

proposed for use in one or more of the alternatives, four (chlorsulfuron, picloram, metsulfuron methyl and 

tebuthiuron) have some effect on soil organisms, generally reducing but not eliminating local populations for a 

limited period of time31. Eight herbicides (2,4-D, clopyralid, dicamba, diuron, fluridone, glyphosate, sulfometuron 

methyl, and triclopyr) have no or slight adverse effect on soil organisms, with some showing increases after 

herbicide treatments. There are no known studies for effects from imazapic to soil organisms. Very little if any 

study of soil organisms has been conducted on six herbicides (bromacil, diflufenzopyr, diquat, hexazinone, and 

imazapyr). Of the studies that have been conducted, effects have been demonstrated but at application rates many 

times higher than the typical rates proposed for use on Oregon BLM lands, or the decrease in soil organisms is 

temporary. Populations have increased in some situations.

30 Various studies have been done on individual algae species present in soil crusts; however, only a handful of the studies 

focused on herbicides that the BLM is proposing, and of those, results were variable. Positive, neutral, and negative effects 

were attributed to 2,4-D; positive and negative effects were attributed to diuron and diquat; neutral and negative effects 

were attributed to picloram; negative effects were attributed to bromacil; and, positive effects were attributed to 2,4-D + 

picloram (Metting 1981). Metting cites several authors who caution against extrapolating this information to the field.

31 This lasts for anywhere from a few days to three weeks. Population levels can be reduced for up to two months if rates 

exceed typical field application rate or if coupled with secondary applications of a second herbicide. 
179

If herbicides reduce macro and microorganisms, herbicides will persist in the soil longer as other means (e.g., 

hydrolysis) may become the primary breakdown mechanism. If noxious weeds have changed the soil chemical or 

moisture contents in a manner that changes the variety or overall amount of these organisms, herbicide persistence 

may be extended. Finally, disturbance from mechanical treatments or animal traffic particularly on wet soils could 

compact the surface layer to a point that these organisms would lose their ability to degrade the applied herbicides.

Erosion and Compaction are closely related. Compaction decreases soil pore space and increases soil density, 

decreasing productivity and reducing the ability of the soil to infiltrate water. Without the infiltration of water into 

the soil, soil organisms or water bound to soil particles cannot interact with the herbicides to break them down. 

Decreased infiltration means more water running across the surface, eroding soils (particularly those particles 

loosened by raindrop impact) and potentially moving herbicides off site. Traffic on the surface, be it wheeled 

or tracked vehicles, animals, or human feet can cause compaction as well as disturbance of the soil. Bare or 

compacted soils can be colonized by noxious weeds more readily than native plants, as weeds tend to be more 

adapted to establishing on such altered sites.

Vegetation is the most significant factor in controlling erosion because it intercepts precipitation, reduces rainfall 

impact, restricts overland flow, and improves infiltration. Noxious weed infestations have been shown to increase 

soil erosion in comparison to soil occupied by native grass species (Lacey et al. 1989). Weeds have less capacity 

to dissipate the kinetic energy of rainfall, overland flow, and wind that causes soil erosion, when compared to the 

native species on the site (Torri and Borelli 2000, Fryrear 2000).

East of the Cascades, wind is the primary element of erosion. Wind can remove soil particles under certain 

conditions of low vegetative cover, dry soil, high percentage of fine clays, and sufficient wind velocity. While 

wind erosion on rangelands is difficult to quantify, the presence of natural vegetation and soil crusts on most 

rangelands is generally sufficient to keep wind erosion from becoming a serious problem. Erosion selectively 

removes organic matter and the finer-sized soil particles that store nutrients for plant use, leaving behind soil 

with a reduced capacity to supply nutrients (Brady and Weil 1999). Herbicides bound to soil particles can be 

transported off-site by blowing soils, negatively affecting non-target areas. According to NRCS data, soils rated 

as Group 1 or 2 for wind erosion risk are most likely to demonstrate this condition. These soils make up 445,000 

acres of BLM lands primarily in the Deschutes, north part of Lake and the south portion of Jefferson Counties. A 

portion of these acres also reside in Umatilla, Klamath, Morrow, Gilliam, and Clackamas counties (Figure 4-5).

Parameters that Affect the Fate of Herbicides in Soils: The ability of soils to hold and breakdown herbicides 

is affected by soil biological processes (organisms and plant uptake), physical parameters (adsorption, photo 

degradation, volatilization, hydrolysis, and leaching), and physical parameters (climate and vegetation cover). 

Characteristics of the 18 herbicides that influence the effectiveness of these parameters and processes are shown 

on Tables 4-14 and 3-1.

The rate at which an herbicide degrades is expressed as the half-life. The half-life is the amount of time it takes 

for half of the herbicide to be converted into other chemical components, or its concentration is half of its initial 

level. The half-life of an herbicide can be affected by its formulation, soil type, and environmental conditions 

(e.g., temperature, moisture). The fate of the herbicide before it degrades is affected by plant uptake, soil 

sorption, leaching, and volatilization.

Plant uptake is outside the scope of this discussion (see the Native and Other Non-Invasive Vegetation section earlier 

in this Chapter) and volatilization occurs when the herbicide releases into the air. Leaching is caused by movement 

in water, which is affected by how tightly the herbicide is bound to the soil particles. Herbicides degrade or break 

down into elements such as carbon, oxygen, hydrogen, and nitrogen. Some may form intermediate compounds. 

On the plant or soil surface, primary breakdown is by photolysis or volatilization. In the soil, microorganisms 

metabolize the herbicide, it is broken down by water (hydrolysis), or it is moved through the soil in water-leaching.

Final Environmental Impact Statement, Chapter 4: Soil Resources
 180

Figure 4-5. 

Wind Erosion

Risk

Groups 1 and 2

Vegetation Treatments Using Herbicides on BLM Lands in Oregon
181

The ability of a soil to bind to an herbicide (while it breaks down) is based on its adsorption affinity. Herbicides 

vary in how tightly they are adsorbed to soil particles. Koc measures the affinity for herbicides to “sorb” to organic 

carbon. The higher the Koc value, the stronger the tendency for the herbicide to attach to, and potentially move 

with, the soil. The Koc value listed in the table below is a measure of the number of milliliters of the individual 

herbicide that can be bound by one gram of organic matter. Herbicide Koc values greater than 1,000 ml/g indicate 

strong adsorption to soil whereas low Koc values (less than 500) tend to allow movement with water more so than 

movement adsorbed to sediment. Off-site movement is also affected by the formulation of the herbicide, soil 

properties, rate and method of application, frequency and timing of rainfall or irrigation, and depth to ground water.

Herbicides can be either selective or non-selective. Selective herbicides remove only specified types of plants 

such as broadleaf, grasses, or a subset of those. Spot treatments with any herbicide, or broadcast treatments using 

selective herbicides, will retain some degree of cover and root masses on the site, reducing or preventing the 

potential for surface erosion. Herbicides can also be applied directly to the soil, usually decreasing the risk of 

drift (when compared with foliar sprays) and more quickly binding the herbicide to soil particles. Generally, the 

soil-applied herbicides included in this EIS are relatively persistent. They are applied before vegetation sprouts 

out of the ground (a pre-emergent herbicide),

Soil/herbicide interaction parameters are included on Table 4-14 as well, and are described in the table footnotes.

Table 4-14. Selected Characteristics that Affect the Fate of Herbicides in Soils

Herbicide Half-life in 

Soils (days)

Fate in Soils

(Persistence Rating1 based on half-life)

2,4-D 10 Rapid microbial degradation 1-4 weeks (Non-Persistent)

Bromacil 60 but may be 

up to 240

Degrades with biological activity in anaerobic soil but slow in aerobic soil (Moderately Persistent to Persistent)

Chlorsulfuron 40 Relatively rapid degradation by microbial and chemical actions, trace amounts have extreme bioactivity 

(Moderately Persistent)

Clopyralid 40 Biodegradation is rapid in soil, reducing the potential for leaching or runoff. Possible release of herbicide from 

decaying plants with uptake by other plants (Moderately Persistent)

Dicamba 14 Mobile in soil but easily degraded by microbes(Non-Persistent)

Diflufenzopyr 2 to 14 Biodegradation, photolysis, and hydrolysis are the primary mechanisms that remove diflufenzopyr (NonPersistent)

Diquat 1,000 Quickly and irreversibly adsorbed to soil colloids, thus no soil activity (Very Persistent)

Diuron 90 Microbial degradation generally only one season (Moderately Persistent)

Fluridone 21 Adsorption increases with clay content, organic matter, cation exchange capacity, and decreasing pH (NonPersistent)

Glyphosate 47 Tightly adsorbed and rapidly degraded by microbes, thus no soil activity (Moderately Persistent)

Hexazinone 90 Organic matter does not affect adsorption. Relatively low affinity for soil particles, dissolves in soil water. 

Bio-degradation is an importation fate (Moderately Persistent to Persistent)

Imazapic 120 to 140 Primarily bio-degradation. Sorption to soil increases with decreasing pH and increasing organic matter and 

clay content (Persistent)

Imazapyr 25 to 141 Adsorption is affected by aluminum and iron in soil more than by clay and organic matter, subject to microbial 

degradation except in cool temperatures (Moderately Persistent to Persistent)

Metsulfuron 

methyl 30 Hydrolysis and microbial degradation, with the latter being the only major pathway in alkaline soils (NonPersistent)

Picloram 20-300 Very slow microbial degradation and some photolysis. Persistent for a year or more (Moderately Persistent to 

Persistent)

Sulfometuron 

methyl 20 Relatively rapid microbial and chemical degradation. Trace amounts have extreme bioactivity (Non-Persistent)

Tebuthiuron 360 Microbial degradation (Very Persistent)

Triclopyr 46 Degradation primarily through microbial metabolism, photolysis, and hydrolysis. As plants die, release of 

triclopyr can occur and can then be taken up by other plants. (Moderately Persistent) 1 Persistence based on half-life in soils except for fluridone which is residency in water, 3 categories: non persistent -- less than 30 days; 

moderately persistent -- 30 to 100 days; and persistent -- greater than 100 days (Extoxnet PIP)

Final Environmental Impact Statement, Chapter 4: Soil Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 182

Additional Information about the Fate and Effects of Herbicides

2,4-D has a very short half-life that averages 10 days in moist soil. Its fate is dependent on soil acidity or 

alkalinity (pH). A soil pH of 7.0 is neutral. Acid soils measure between 1 and 7 on the pH scale whereas alkaline 

soils measure between 7 and 14. 2,4-D on a Spodosols would resist to degradation, but on a Mollisols, it would 

readily degrade in a warm and moist environment. 2,4-D is readily broken into simpler components in alkaline 

soils but the break-down is slower in acidic soils. Temperature affects degradation as well, with slower breakdown in cold or dry soils or where microbial organisms are not present. Warm, moist soils previously treated 

with 2,4-D have been shown to dissipate the herbicide more rapidly due to the presence of bacteria that degrade it 

(Oh and Tuovinen 1991, Smith and Aubin 1994, Shaw and Burns 1998, all cited in Tu et al. 2001). Furthermore, 

most studies of the effects of 2,4-D on microorganisms concluded that the quantity of 2,4-D reaching the soil from 

typical applications would probably not have a serious negative effect on most soil microorganisms (Bovey 2001).

Bromacil is applied to soil where it binds, or adsorbs, only slightly to soil particles, is soluble in water, and is 

moderately to highly persistent. Its half-life is about 60 days, but may be as much as 8 months in aerobic soils 

(Wauchope et al. 1992). Soil persistence is longer in soils with high organic matter (National Library of Medicine 

2002, Extoxnet 1993). Leaching is dependent on the soil type and the amount of rainfall or irrigation water. The 

potential for bromacil to leach and contaminate groundwater is greatest in sandy soils. In normal soils, it can 

be expected to leach to a depth of 2 to 3 feet (National Library of Medicine 2002). There is limited research on 

the toxicity to most soil organisms. However, one soil bacterial isolate that can biodegrade bromacil has been 

identified (Chaudhry and Cortez 1988).

Chlorsulfuron degrades in acidic soil by hydrolysis, but is more stable in neutral soils. As with most 

biodegradation rates, the higher the pH, the slower the herbicide breaks down. The higher the temperature, soil 

moisture, organic matter content, and microbial biomass, the faster it breaks down. Chlorsulfuron is only mildly 

toxic to terrestrial microorganisms and effects are short term (transient) (SERA 2004a).

The herbicide can remain active for more than a year. Sarmah et al. (1999) observed that the rate of chlorsulfuron 

degradation in alkaline subsoils was slow. They concluded that under conditions conducive to leaching in alkaline 

systems, prolonged persistence of chlorsulfuron in the soil profile is possible. It is likely that in some soils 

dissipation rates could be slower than the reported average, including arid soils with high pH and low organic 

matter. Such longevity could occur on the slightly (pH 7.4-7.9) and moderately (pH 7.9- 9.4) alkaline soils within 

the Aridisols, Mollisols, Inceptisols, and Entisols soil orders.

Clopyralid is unstable in soil and is considered moderately persistent based on its half-life. It will leach under 

favorable conditions such as wet, sandy soils like Inceptisols or Andisols as it does not bind to soil tightly. 

However, biodegradation is rapid in soil and thus the potential for leaching or runoff is low. Clopyralid can 

persist in plants and therefore can be introduced into the soil when plants die, therefore killing other plants.

Diuron is a moderately persistent herbicide with low to moderate mobility in soil, depending upon the level of 

organic matter available for it to adhere to. Decomposition is principally through biodegradation and occurs in 

both anaerobic and aerobic conditions. As degradation occurs, the breakdown product 3,4-DCA also persists and 

exhibits higher toxicity to some receptors32. Waterfleas are negatively affected but it is unknown if it affects soil 

crustaceans. Bacteria and fungi have been found to degrade this herbicide and population levels within the soil 

may increase. Thus, effects to them may be positively correlated. One study found adverse effects on bacteria 

diversity at concentrations of 25 mg/L and diversity seemed to decrease in soil treated with diuron (Giacomazzi 

32 An ecological entity such as a human, fish, plant, or slug.
183

and Cochet 2004). According to the European Food Safety Authority’s Conclusion on the Peer Review of Diuron 

(EFSA 2005), the risk from label applications to bees, non-target arthropods, and soil micro- and macro-organisms 

including earthworms is considered low for diuron and its metabolites. 

Dicamba is moderately persistent in soil. The half-life of dicamba in soil is typically 1 to 4 weeks. Under 

conditions suitable for rapid metabolism, the half-life is less than 2 weeks. Metabolism by soil microorganisms 

is the major pathway of loss under most soil conditions. The rate of biodegradation increases with temperature 

and increasing soil moisture, and tends to be faster when soil is slightly acidic. When soil moisture increases 

above 50 percent, the rate of biodegradation declines. Dicamba slowly breaks down in sunlight. Volatilization 

from soil surfaces is probably not significant, but some volatilization may occur from plant surfaces. It is stable 

to water and other chemicals in the soil. Dicamba does not bind to soil particles and is highly soluble in water. It 

is therefore highly mobile in the soil and may contaminate groundwater. In humid areas, dicamba will be leached 

from the soil in 3-12 weeks (Howard 1991). The breakdown product is 3,6-dichlorosalicylic acid that is adsorbed 

strongly to soils but is moderately toxic to earthworms (IUPAC 2009).

Diflufenzopyr: Biodegradation, photo-degradation, and hydrolysis are the primary mechanisms that remove 

diflufenzopyr from soil. It is not considered persistent. Diflufenzopyr appears to be soluble enough that transport 

in surface runoff is possible, especially in neutral to alkaline soils.

Diquat is readily adsorbed to clay soil surfaces, becoming effectively immobilized by soils with high clay content. 

Diquat is resistant to anaerobic and aerobic biodegradation, possibly in part because it adsorbs so well to soil 

particles. It is considered a highly persistent herbicide with a half-life of 3 years or longer.

Fluridone is an aquatic herbicide that adsorbs to the surface area of sediment particles within the water column. 

Particles with greater clay content, organic matter content, cation exchange capacity, and lower pH are more 

reactive. Some studies have found fluridone can persist on dry soils longer and may last up to a year, but 

fluridone is an aquatic herbicide not proposed for use on dry sites. Persistence rating of non-persistent is based 

on time remaining in an aquatic environment. Volatilization can occur slowly on wet soils but not dry ones. No 

toxicity to earthworms was found when tested with rates up to 1,000 times the typical use rate.

Glyphosate binds tightly to soil particles. This binding increases with increasing clay content, organic matter and 

decreasing soil pH. Glyphosate is biodegraded by soil organisms and many use it as a source of carbon. There is 

little information indicating that it is harmful to soil microorganisms and may benefit some (Busse et al. 2004).

Hexazinone has a low affinity for soil particles and dissolves in soil water. It has a low to moderate persistence 

based on a 90-day half-life. Soil organic matter does not affect adsorption. Soil organisms do not appear to 

be affected by hexazinone (based on soil respiration and nitrogen cycles) when applied at the recommended 

application rate, and the capacity for beneficial mycorrhizal fungi to infect conifer seedlings was unaffected 

(Busse et al. 2004).

Imazapic is moderately persistent in soils and has not been found to move laterally with surface water. Most 

imazapic is lost through biodegradation. Sorption to soil increases with decreasing pH and increasing organic 

matter and clay content. Little is known concerning the effects of imazapic on soil organisms or processes.

Imazapyr does not readily bind to mineral soils, but is likely to bind relatively strongly to organic soil. Imazapyr 

may persist in soil for a prolonged period in relatively arid regions, and does not bind tightly to alkaline soils 

with low organic matter. Imazapyr can be released from treated plants into the soil, where it remains active and 

can kill non-target plants (Tu et al. 2001). There are no studies on the effects of imazapyr on soil invertebrates, 

Final Environmental Impact Statement, Chapter 4: Soil Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 184

and incomplete information on the effects on soil microorganisms (USDA 2007a). Field studies indicate that 

imazapyr remains in the top 20 inches of soil and do not indicate any potential for imazapyr to move with surface 

water. In forest field studies, imazapyr did not run off and there was no evidence of lateral movement. Modeling 

results indicate imazapyr runoff is highest in clay and loam soils with peaks after the first rainfall. Imazapyr 

percolation is highest in sandy soils (SERA 1999, Vencill et al. 2002).

Metsulfuron methyl has the principal modes of degradation of hydrolysis and microbial degradation, with the 

latter being the only major pathway in alkaline soils (Sarmah et al. 1998). Degradation rates are affected by soil 

temperature, moisture content, and soil pH. The chemical will degrade faster under acidic conditions, and in soils 

with higher moisture content and higher temperature (Smith 1986). Half-lives in acidic or neutral soils vary from 

5 to 190 days (Sarmah and Sabadie 2002, SERA 2004e). In alkaline soils, adsorption is very low and leaching 

potential is high. This is likely to result in increased persistence in alkaline soils such as the Aridisols, Mollisols, 

or Entisols.

At surface application rates of 0.04 to 0.067 lb/ac (between typical and maximum rates), decreases in soil 

bacteria were apparent for 3 days but reversed completely after 9 days. Biodegradation of metsulfuron methyl 

increased as soil moisture increased from 20 percent to 80 percent of field capacity, and half-life decreased when 

temperature was raised from 20° to 30°C (Ismail and Azlizan 2002).

Picloram is broken down primarily through photolysis and biodegradation mechanisms of dissipation (USDA

2000b). Picloram adsorbs to clay particles and organic matter, but if the soil contains little clay or organic matter, 

picloram is easily moved by water. Picloram has been reported to remain active in soil at levels toxic to some 

plants for more than 1 year at typical application rates (SERA 2003b). The half-life of picloram in soil is reported 

to vary from 1 month under favorable environmental conditions to more than 4 years in arid regions (USDA

2000b). Picloram can be persistent in plants. When plant parts containing picloram degrade, they may release it 

into the soil, where it can kill other plants.

The persistence of picloram in soil is dependent on soil moisture and temperature; warm and moist soils degrade 

this herbicide readily. Picloram dissipates most slowly when soils are alkaline, fine textured, and low in organic 

matter. Picloram degrades more rapidly under anaerobic than aerobic conditions and at lower application rates 

(USDA 2000b). There does not appear to be a defined threshold for picloram toxicity to soil microorganisms 

(SERA 2003b). 

Sulfometuron methyl is broken down through hydrolysis and biodegradation. The half-life is short (Table 

4-14). It has been found to move readily through coarse textured soils such as sand and sandy loams under field 

conditions, but Trubey et al. (1998) demonstrated it is immobile under field conditions and does not pose a threat 

to groundwater. Little is known about the effects to soil organisms; however, Busse et al. (2004) demonstrated 

that this herbicide does not alter the capability of mycorrhizal fungi to infect roots even at concentrations 

detrimental to seedling growth.

Tebuthiuron is resistant to abiotic degradation and biodegradation. Its field half-life ranges from 2 weeks to over 

33 months making it a highly persistent herbicide. It has a low adsorption affinity to soil, with some adsorption 

occurring as organic matter and clay content increase. It is mobile in soil and has been detected in groundwater. 

Soil organisms (mycorrhizal spore density) have been reduced initially after applications in Utah under a soft 

brome vegetation type (Allen and West 1993). However, Mostafa and Helling (2003) found no affect to such 

spores 6 months after herbicide application.

Triclopyr is manufactured in two forms: a triethyamine salt (TEA) and a butoxyethyl ester (BEE). Both forms 

degrade readily in sunlight to the parent compound, triclopyr acid, which is also photodegradable. A study 
185

of photolysis found the half-life of triclopyr acid on soil under midsummer sun was two hours (McCall and 

Gavit 1986). Degradation occurs primarily through microbial metabolism, but photolysis and hydrolysis can 

be important. Therefore, in general, moist soils with high organic matter content support the highest rates of 

metabolism. Johnson et al. (1995) found that microbial degradation of triclopyr was significantly higher in moist 

versus dry soils, and at 30oC versus 15oC. Photodegradation can be particularly important in water. Johnson 

et al. (1995) found triclopyr acid dissolved in water had a half-life due to photolysis of one to 12 hours. They 

also found that sunlight plays a role in the rate of microbial metabolism of triclopyr, as microbial metabolism 

slowed when soil was deprived of light. The average half-life of triclopyr acid in soil is 30 days (Tu et al. 2001). 

Triclopyr can be persistent in plants and when they die, release of triclopyr can kill other plants. No information 

is available for toxicity of triclopyr acid in soil.

Effects by Alternative

Reference Analysis – No Herbicide Use

Under the Reference Analysis, weeds on approximately 42,000 acres would be controlled through manual and 

mechanical means, with prescribed fire, directed livestock, biocontrol, and seeding and planting the methods 

of choice. All but biocontrol can be mildly to intensively site disturbing. Site productivity would be reduced 

where erosion and compaction occur, particularly on the Vertisols, Ultisols, and Inceptisols. Wind erosion on 

excessively bared soil orders that have low T Factor33 ratings such as the Aridisols and Mollisols could result in 

the loss of valuable surface nutrients, organic matter, and overall productivity. The bare soil would also be prone 

to re-colonization from remaining seed or nearby weeds not eliminated by the treatment.

Directed livestock (three times higher under this strategy than under any other), and mechanical treatments (1,600 to 

2,000 acres higher than under any of the alternatives) can compact the soil where repeated passes of machines and 

animals occur on overly moist or wet soils (e.g., the wetter riparian areas, upslope early in the spring, or immediately 

after intense thunderstorms). As discussed earlier in this section, compaction directly degrades soils, inhibits plant 

growth, and decreases infiltration which leads to overland water flow and related erosion. Not all mechanical 

treatments would expose soil to erosion processes; chainsaw use is included in these acres for example.

The use of fire as a treatment method is expected to be reduced by 2,000 acres (35 percent) compared to the No 

Action Alternative (Alternative 2), which would reduce the number of burned acres. However, without follow-up 

herbicides, success of subsequent seeding will be variable and weed effects to soils could continue. Adverse soil 

effects directly from the burning would be limited, as controlled burning of weed sites is normally done at lower 

intensities than most wildfires. Lower intensity fires leave more of the existing organic matter in place and avoid 

deep heating of the soil that may kill microorganisms and reduce site productivity.

Fewer weed acres would be treated under this strategy, and it is predicted that treatments would be 30 percent 

effective. Implications to soils include the need to retreat about 70 percent of treatment areas, compounding 

adverse effects of treatments, and weeds would spread at a faster than current rate. Noxious weed spread is 

projected to increase to 14 percent per year without herbicides, and infest 2.7 million more acres in 15 years 

than under Alternative 2 (No Action; Table 4-4 in the Noxious Weeds and Other Invasive Plants section in this 

Chapter). On these acres, invasive plants would continue to alter vegetation types and organic matter levels 

(both on and within the soil). Weeds can out-compete native vegetation and lead to increased soil exposure; 

resultant increased erosion would remove soil and nutrients. Changes to the type and abundance of various soil 

microorganisms because of lower organic matter contents would be expected to hinder processing and storage 

of water or cycling organic matter into nutrients for plant growth. Weeds can out-compete native species in part 

33 T Factor: Tolerable amount of soil loss (tons per acre per year) prior to reduced productivity.

Final Environmental Impact Statement, Chapter 4: Soil Resources
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because they have high nutrient uptake rates and can deplete soil nutrients to very low levels, especially in cases 

where weed species initiate spring growth prior to native species and exploit nutrient and water resources before 

native species are actively growing (Olson 1999).34 Any of these changes would result in less productive lands for 

native vegetation and reduce the potential for restoring the original vegetation community, often permanently.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Under this alternative, invasive plants would be treated on approximately 45,500 acres; 16,700 acres (37 

percent) with herbicides. This alternative would have the lowest overall number of acres potentially exposed or 

disturbed with non-herbicide methods of all of the alternatives. The lowered level of disturbance would benefit 

soils; reducing soil disturbance would reduce adverse effects to soil functions when compared with the other 

alternatives. Treatments baring soils could result in wind and rain erosion. However, the vast majority (93 

percent) of treatments between 2000 and 2007 have been applied with ground-based equipment or with the use of 

backpack sprayers, trucks, or ATVs off road. These traditionally have been spot treatments that do not completely 

remove vegetation from extensive areas at any one time. Even the remaining 7 percent that has been applied 

aerially is usually done with selective herbicides designed to retain the native plant component of the infested 

area, providing some protection from either wind or rain erosion.

Picloram has a 90 day half-life, but may remain active in soil at levels toxic to some broadleaf plants for about 

one year at typical application rates (Extoxnet PIP). 2,4-D, dicamba, and glyphosate have half-lives between 

10 and 50 days in the soil. Picloram is the only herbicide under this alternative that is documented to affect soil 

organisms in a negative way (USDA 2005a:4-110). 2,4-D may increase bacteria that degrade the herbicide (Oh 

and Tuovinen 1991 cited in Tu et al. 2001). Busse et al. (2004) determined that both direct and indirect soil 

microbial characteristics in the top 4 inches of soil were generally unchanged after 9 to 13 years of continuous 

vegetation control by glyphosate. Thus, soil quality would not be degraded using herbicides other than picloram 

to control noxious weeds under this alternative.

The highest risk of herbicide movement under this alternative would be for dicamba or picloram used on Alfisols, 

Entisols, Spodosols, and Andisols or other orders with sandy soil textures or low amounts of organic matter. 

Under these conditions, these herbicides are easily moved by water both laterally and vertically through surface 

runoff or leaching respectively. It is generally accepted that 2,4-D is rapidly inactivated in moist soil; however, its 

persistence is largely dependent on pH.

The use of prescribed fire for weed control would create an erosion risk for temporarily bared soils. Follow-up 

use of glyphosate35 could extend the time the soil would be bare, increasing the risk of erosion, notably from wind 

since these treatments are generally done on porous soils on gentle terrain east of the Cascades. 

This alternative is projected to result in about 5.8 million acres, or one-third, of the BLM lands in Oregon 

being infested with noxious weeds in 15 years, and at least an additional five million acres being infested with 

cheatgrass. The negative effects of these weeds to soils (see Reference Analysis) would far exceed the negative 

effects likely from any of the weed control treatments envisioned under this alternative.

34 For example, leafy spurge displaces native vegetation in prairie habitats through shading and usurping available water 

and nutrients. Leafy spurge also secretes toxins that prevent the growth of other plants near it. Once present, this 

aggressive invader can completely overtake large areas of open land.

35 Glyphosate can be effective on some annual grasses, but PEIS Mitigation Measures limits use on rangeland to spot 

treatments.
187

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Adverse effects from herbicides proposed for Alternative 3 are expected to be slightly more than or equal to those 

from the four herbicides in Alternative 2 (No Action); acres would increase but total pounds of herbicide applied 

would be down 35 percent and available herbicides include herbicides that are less toxic to slightly toxic to soil 

organisms. Any additional risk would be related to herbicides with the longest persistence rate or herbicides 

that can become mobile after use. The proposed 11,500 acres of imazapic and 1,500 acres of imazapyr may 

adversely affect soil functions compared to herbicides used in Alternative 2, because of their unknown impact 

to soil organisms, their mobility, and their ability to release from dead plant material and kill other vegetation. 

Imazapic on medusahead has an advantage over the currently used glyphosate, because it is more selective for 

invasive annual grasses, thus better retaining remaining ground cover of shrubs and perennial annual grasses that 

help protect soils. Sulfometuron methyl may be used on invasive annual grasses west of the Cascades in place of 

imazapic partly because it has a half life of 20 days rather than 130, making it more environmentally friendly and 

allowing restoration to proceed quickly (rather than leaving bare ground exposed to the rains).

West of the Cascades, a minor reduction (100-300 acres) in mechanical and fire treatments will occur in this 

alternative when compared to Alternative 2 (No Action). Planting treatments increase by 100 acres and manual 

treatments remain the same. Thus, no change in risk between Alternatives 2 and 3 is expected.

East of the Cascades, the 7,000-acre increase in prescribed fire under this alternative, when compared to the No 

Action Alternative (Alternative 2), would increase the risk of wind and water erosion until these areas supported 

vegetation capable of anchoring the top surface of the soil from the effects of wind and water removal (one to two 

growing seasons). Using mechanical means (range drills) for a portion of the additional 5,000 acres of seeding or 

planting would increase soil disturbance as well. However, this increase would be minor as soil Standard Operating 

Procedures and PEIS Mitigation Measures would minimize adverse effects of soil disturbance. If aerial seeding is 

used, that increased risk of soil disturbance would not occur (although aerial seeding may not be as effective).

The projected reduction of weed-infested acres by 1.9 million acres in 15 years compared to the No Action 

Alternative would provide benefits to soils that would more than offset the soils risks described here.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

Effects described for Alternative 3 also apply to this alternative with the following exceptions. Herbicide treated 

acres would increase about 50 percent when compared with Alternative 3, although most of those acres would be 

along rights-of-way and around administrative and recreation sites. Increased risks would be incurred from the use 

of bromacil, diuron, and tebuthiuron because these herbicides persist longer, have greater risk of runoff, and are nonselective when compared to other proposed herbicides in Alternative 3. The effect to soil resources would include a 

greater area of exposure (thus possible erosion) and longer residence time of the herbicide in the soil, which would 

thus reduce biological organisms and their nutrient cycling processes. Some of these effects would be resolved once 

native vegetation returns to the sites in the next several growing seasons, although some disturbed sites would be 

maintained in a somewhat vegetation free state, to protect adjacent structures and other improvements. If similar 

acreage was treated with non-herbicide methods to remove the vegetation, it would involve mechanical equipment 

and expose soil to erosion and compaction risks that would be greater than herbicide risk.

This alternative is projected to prevent noxious weed infestations on an additional 2.2 million acres when 

compared to the No Action Alternative (Alternative 2), further reducing the adverse noxious weed effects 

described under the Reference Analysis.

Final Environmental Impact Statement, Chapter 4: Soil Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 188

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Effects under this alternative would be similar to those for Alternative 4 (Proposed Action). An additional 5,000 

acres would be treated with herbicides, mostly as habitat improvement treatments having little or no effect on 

soils, as they would occur on the drier eastside Aridisols or Mollisols. The availability of all 18 herbicides would 

include minor additional use (0-200 acres) of most herbicides. Effects from diquat and diflufenzopyr + dicamba 

would be minor considering the limited use proposed. The increased use of imazapic by 2,000 acres would 

slightly elevate risks to soils but not the increased use of 2,4-D.

Cumulative Effects

In general, declines in soil productivity are directly associated with greater loss of soil through erosion and 

displacement, loss of soil organic matter, changes in vegetation composition, removal of whole trees and 

branches, and increases in bulk density from compaction. Standard Operating Procedures and PEIS Mitigation 

Measures (Appendix 2) would prevent soil productivity loss, and any degradation of soils from the herbicide 

applications proposed in this EIS would be de minimus in the context of other management activities and events 

(including invasive plant spread) likely to occur on the same sites.

Water Resources

Affected Environment

Water resources are classified as surface water or groundwater. Surface water resources include rivers, streams, 

lakes, ponds, reservoirs, and wetlands. The major river system in Oregon is the Columbia with the main 

tributaries of the Willamette River in the west, the Deschutes and Snake River to the center and east. The 

Klamath River flows from southern Oregon into northern California. The west side of the Coast Range and 

southwestern Oregon has many short steep streams that drain directly to the Pacific Ocean. Southeastern Oregon 

has some closed basins that do not drain into any external system.

Groundwater occurrences are of two types: unconfined shallow aquifers within unconsolidated sediments and 

deeper aquifers with a confining layer above (USGS 1994).

Aquatic Conservation Strategy standards and guidelines for Riparian Reserves have been included in all 

resource management plans through the Northwest Forest Plan (USDA, USDI 1994a) west of the Cascades and 

at Klamath Falls. Resource Management Plans east of the Cascades and outside of Klamath Falls include their 

own riparian management direction and best management practices36 to protect and improve water quality and 

riparian function. Each district follows INFISH (USDA 1995b) direction wherever bull trout or its designated 

Critical Habitat are present, and each follows PACFISH (USDA, USDI 1995) direction wherever Federally Listed 

anadromous salmonids are present. Standards and guidelines in the PACFISH and INFISH strategies are designed 

to provide for the attainment of riparian management objectives, which improves and protects riparian areas and 

water quality.

36 Manual-directed standard operating procedures and other standing direction are often referred to as best management 

practices, particularly when they apply to water.
189

Final Environmental Impact Statement, Chapter 4: Water Resources

Flows

There are 6,728 miles of perennial stream and 13,679 miles of intermittent streams on BLM land in western Oregon 

and 2,453 miles of perennial and 33,835 miles of intermittent streams on BLM land in eastern Oregon. In general, 

the high flows are found in western Oregon from October through May with highest flows likely from winter rains. 

In eastern Oregon, highest flows are found in the spring from snowmelt. In both areas, rare peak flows occur with a 

rain-on-snow event at low to mid-elevations. Low flows occur in the summer when precipitation is low and water 

withdrawals (generally for irrigation) are at their highest. The timing, magnitude, duration, and spatial distribution of 

peak flows helps create and sustain riparian and aquatic habitat (USDA et al. 1993).

Water Quality

Water quality standards are established to protect beneficial uses of the State’s waters. Beneficial uses are 

assigned by basin in the Oregon Administrative Rules for water quality. For the State of Oregon, beneficial uses 

include (ODEQ 2009a):

• domestic water supply

• fishing

• industrial water supply

• boating

• irrigation

• water contact recreation

• livestock watering

• aesthetic quality

• fish and aquatic life

• hydropower

• wildlife and hunting

• commercial navigation and transportation

For streams on BLM lands, fish and other aquatic life is the most common beneficial use, although BLM-origin 

waters also supply water districts and private residences.

303(d) Streams

Section 303(d) of the Clean Water Act requires that states develop a list of water bodies that do not meet water 

quality standards and submit the list for approval to the EPA. The Oregon Department of Environmental Quality 

(ODEQ) developed its most current 303(d) list in 2004/2006.

By direction of the Federal Clean Water Act, where water quality is limited, the ODEQ develops Total Maximum 

Daily Load (TMDL) plans to improve water quality and to support the beneficial uses of water. The BLM is 

recognized as a designated management agency for implementing the Clean Water Act (as amended) on BLM 

administered lands within the TMDL management plan. The BLM provides information, analysis, and sitespecific planning efforts to support State processes to protect and restore water quality. Pollutant standards not 

being met on one or more BLM steams are:

Temperature: Temperature is the most widespread water quality impairment on BLM land (Table 4-15). Wellshaded streams often have cooler stream temperatures due to reduced input of solar energy (Brown 1969, Beschta 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 190

et al. 1987, Holaday 1992, Lee et al. 2004). Conditions that can produce highly shaded streams include:

• Riparian areas with fully developed vegetative cover over the channel;

• Deep narrow channels with overhanging banks; and/or,

• Streambeds, banks, and floodplains that capture bed load 

and woody debris, providing channel cover and groundwater 

interaction.

High solar path and air temperatures coinciding with low rainfall and 

low stream flow during the summer months are key factors causing 

elevated stream temperatures within the analysis area. South-facing 

aspects and lower elevations tend to create drier and hotter conditions, 

which serve to further elevate temperatures.

Dissolved Oxygen: High loading of organic matter and nutrients, combined with sediment and increased water 

temperature can deplete dissolved oxygen in small streams (Ringler and Hall 1975). Growth of algae with 

associated fluctuations in night and day respiration can lower dissolved oxygen at night. This process is limited to 

low-gradient streams with high algae growth. The ability of water to hold oxygen decreases with increased water 

temperature, altitude, or dissolved solids.

Bacteria: Bacteria occurs naturally in water, with sources often associated with the aquatic and terrestrial biotic 

populations. Land management introduction of bacteria has common sources linked to recreation and livestock 

grazing. Concentrated uses by humans and livestock in the riparian and channels can elevate bacteria populations 

presenting risk to downstream uses such as domestic water consumption and recreation. 

Sediment: Landslides and roads are the most common route for sediments to enter streams. Fine-grained 

sediments associated with roads that cross or parallel streams are the greatest management related problem for 

water quality. Roads may divert water and sediment from natural paths directly to a stream depending on road 

ditch line connection to streams, number of relief culverts, and number of stream crossings (Wemple et al. 2001).

Metals: Metals (including copper, lead, mercury, nickel, silver, and zinc) are most common around mining, 

agriculture, and natural sources found in certain rock types. Mercury is the most common metal of concern.

Pesticides: While no segments of streams or water bodies on BLM managed land are on the 303(d) list for 

herbicides, a few water bodies within the state are listed. According to the Oregon Pesticide Management Plan 

for Water Quality Protection (2008), most of the 303(d) listings for herbicides are due to “legacy” pesticides 

that are no longer marketed, such as DDT/DDE, aldrin, dieldrin, chlordane, and heptachlor. There are a few 

water bodies listed for currently used pesticides: chlorpyrifos (Indian Creek, Lenz Creek, and Neal Creek in the 

Hood River watershed plus West Fork Palmer Creek in the Yamhill River watershed), guthion, (Neal Creek), and 

pentachlorophenol (Willamette River) (ODEQ 2006). None of these pesticides are proposed for use under this EIS.

Source Water Protection

The 1996 Safe Drinking Water Act amendments require the identification and management of source water 

protection areas for public water systems (Figure 4-6). States are required to develop source water assessments 

for public drinking water supplies including both surface and groundwater sources. These watersheds are usually 

in rural settings and do not involve industrial contaminant sources.

Table 4-15. Miles of BLM Streams

on ODEQ 303(d) List

ODEQ 303(d) listed 

pollutant Miles impaired 

Temperature 1711

Dissolved oxygen 206

Bacteria 64

Sediment 61

Metals 50
191 Figure 4-6. 

Source Water Protection

Final Environmental Impact Statement, Chapter 4: Water Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 192

The ODEQ has recommended that BLM establish direct communication with Public Water System operators or 

community liaisons downstream of BLM planned projects with potential to affect water quality. BLM would 

consult with all interested communities during site-specific analysis. To protect public water supplies (PWS), the 

ODEQ also generally recommends 100 or 200 feet stream buffers within 500 to 1,000 feet of a PWS intake, and 

suggests that BLM’s management in municipal watersheds/aquifers should support the overall goal of providing 

the highest quality water possible downstream at intakes and wells.

In addition to public water systems, private residences sometimes use springs and streams on adjacent BLM land 

for domestic water supplies.

The EPA has set a maximum concentration for specific herbicides in potable water (Table 4-16; EPA 2009c). At 

this time, no maximum concentrations for potable water have been set for the other herbicides.

Table 4-16. Maximum Herbicide Concentration Allowed in Potable Water

Herbicide Potable water standards (μg/l)

2,4-D 70

glyphosate 700

picloram 500

diquat 20

bromacil 0.90

hexazinone 210

Herbicides in Oregon

The Oregon State Legislature (2007) passed Senate Bill 737, which required ODEQ to develop a list of priority 

herbicides based on persistent bioaccumulative toxics with a documented effect on human health. The list 

includes 118 toxic pollutants (ODEQ 2009b). None of the 18 herbicides proposed under this EIS are included 

because they do not meet specific criteria for toxicity, persistence or bioaccumulation potential.

Cooperative Agreement with EPA

As part of a Cooperative Agreement with the EPA, Oregon Department of Agriculture must report on the status 

of pesticides found in ground and surface water. Using the definitions and parameters described below, the State 

annually selects and prioritizes Pesticides of Interest and Concern using the following criteria:

• Previous water quality monitoring data (both within Oregon and surrounding states);

• Pesticide toxicity to environmental and human health;

• Established water quality standards or benchmarks;

• The potential to occur in surface & ground water based on the pesticide’s physical and chemical 

properties; and,

• Pesticide use, land use patterns, and Best Management Practices applied in key watersheds.

Pesticides of Interest (POI): The Pesticides of Interest list represents those pesticides that have the potential to 

occur in ground or surface water at concentrations approaching or exceeding a Federal, State, or Tribal human 

health or ecological reference point. The following herbicides are among those proposed for use under this 

EIS and are on the POI list: 2,4-D, clopyralid, glyphosate, dicamba, diuron, hexazinone, imazapyr, picloram, 

metsulfuron methyl, sulfometuron methyl, tebuthiuron, and triclopyr. Through the use of Standard Operating 
193

Procedures (Appendix 2) and PEIS Mitigation Measures implemented at the project level, BLM applications are 

not expected to reach concentrations above any established reference point.

Pesticides of Concern (POC): A pesticide of concern is a pesticide which is determined to approach or exceed

(or likely to approach or exceed) a human health or environmental reference point in a local area, thus posing 

possible risks to human or ecological life. In most cases, an evaluation is based on available monitoring data from 

within the state. A POC is prioritized and elevated to a higher management level to ensure that concentrations 

are maintained or reduced below an established reference point. The POC reference point quantifies Oregon’s 

efforts to manage pesticides that have been identified as posing a risk to water resources. None of the herbicides 

discussed in this EIS are included on the POC list. 

Herbicides and Monitoring in Oregon

Herbicides were the most common pesticides found in several studies covering wide areas in Oregon to quantify 

pesticide presence in either surface or ground water (Barbash et al. 1999, Wentz et al. 1998, ODA 2008, ODEQ 

2009a). A USGS National Ambient Water Quality Assessment (NAWQA) study detected 2,4-D, bromacil, 

dicamba, diuron, glyphosate and triclopyr in water samples (Wentz et al. 1998).

Table 4-1 shows the 2008 Oregon wide use of the 18 herbicides analyzed in this EIS and compares pounds 

used and acres treated with BLM use under the Proposed Action (Alternative 4). While the BLM manages 

approximately 25 percent of the land in Oregon, it would use less than 1 percent of the herbicides used compared 

to the 2008 total.

In 2008, the Oregon Department of Environmental Quality initiated a long-term program to monitor surface 

waters for toxic pollutants. Monitoring objectives were to collect data on pollutants known to present a 

substantial threat to human health or aquatic life and to gather information about the occurrence of chemicals 

of emerging concern in the Willamette River Basin. Water samples and fish were collected from mainstem 

and tributary locations throughout the basin and analyzed for a wide range of organic pollutants and metals. 

Herbicides were the class of pesticides most commonly found in water samples. Of the herbicides addressed in 

this EIS, diuron was found in many samples collected at locations throughout the basin. There is no numeric 

water quality criterion established for diuron at this time. Concentrations are highest in streams when rain soon 

after application washes it off plants into streams. In eastern Iowa, concentrations of herbicides were highest 

in late spring and early summer when intense rains occurred soon after application (Kalkhoff et al. 2000). On 

Oregon BLM lands, Standard Operating Procedures preclude applications immediately prior to rain.

Groundwater

Groundwater is commonly available from shallow wells in unconsolidated aquifers that consist primarily of sand 

and gravel but contain variable quantities of clay and silt. Many large-yield public-supply and irrigation wells, 

and thousands of domestic wells, access these types of aquifers, generally in areas of privately owned land. In 

many places, deeper wells produce water from underlying volcanic rocks, usually basalt (USGS 1994). A nationwide study by the USGS found that herbicides occur most frequently in shallow groundwater in agriculture and 

urban areas (Gilliom and Hamilton 2006).

According to the Oregon Pesticide Management Plan for Water Quality Protection (ODA 2008), between 

1980 and 2000 ODEQ conducted 45 groundwater quality assessments in Oregon. These assessments covered 

approximately 6.4% of the total land and 30.8% of the area where groundwater is used. The data provided 

a general rating of the overall quality of the groundwater resources available for use as drinking water. The 

Final Environmental Impact Statement, Chapter 4: Water Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 194

data show that nitrate is the most commonly detected contaminant, followed by pesticides, volatile organic 

compounds, and bacteria, respectively.

Groundwater can recharge through rain or snow or along losing reaches of streams.37 There are also more 

localized areas where groundwater lies above the regional ground water table due to a lens of impermeable rock 

or soil. These often discharge as seeps or springs on a hillside (OWRD 2003).

Susceptibility of aquifers to contamination relates to geology, depth to groundwater, infiltration rates, and 

solubility of contaminants. The shallow unconfined aquifers are at greater risk from surface contamination due 

to rapid infiltration from the surface to the water table. The Willamette Valley, Snake River Basin, and Columbia 

Plateau all have elevated levels of nitrates and pesticides in groundwater (Eldridge 2004). These are major 

agricultural areas where pesticide use is subsequently different than uses that would occur on BLM lands.

Environmental Consequences

A primary issue for this analysis is the potential for herbicides to enter streams and affect water quality for 

aquatic species and domestic water sources. Surface and ground waters on and adjacent to BLM lands are 

susceptible to contamination from herbicide applications through direct application, drift, spill, leaching, washing 

(erosion, overland flows), or the deposition of treated soils or vegetation matter into waters. The likelihood 

and significance of this contamination is influenced by the herbicide, adjuvants, temperature, wind, application 

method, soils, rainfall, water use, and other factors.

Effects of Herbicides on Water Resources

Herbicides used for both Aquatic and Terrestrial Vegetation Control

2,4-D: Some salt forms of 2,4-D are registered for use in aquatic systems. 2,4-D is a known groundwater 

contaminant38 although potential for leaching into groundwater is moderate by its being bound to organic matter and 

its short half-life. Concentrations of up to 61 mg/L have been reported immediately following direct application to 

water. Concentrations as low as 0.22 mg/L can damage susceptible plants (Que Hee and Sutherland 1981 cited in Tu 

et al. 2001).

In terrestrial applications, most formulations of 2,4-D do not bind tightly with soils, and therefore have a moderate 

potential to leach into the soil column and to move off site in surface or subsurface water flows (Johnson et al. 

1995 cited in Tu et al. 2001). In a study on groundwater in small shallow aquifers in Canadian prairies, 2,4-D was 

detected in 7 percent of 27 samples (Wood and Anthony 1997).

Diquat would be applied to remove emergent, floating, or submerged aquatic vegetation. In aquatic systems, diquat 

(ionic) adsorbs to sediment, suspended solids, and aquatic vegetation, and becomes immobilized (Simsiman and 

Chesters 1976). Thus, diquat is ineffective in turbid waters. Loss of diquat from aquatic systems, both through 

photolysis and biodegradation, is possible, but only when the herbicide is not adsorbed to solid surfaces. When 

adsorbed, the herbicide is protected from biodegradation and photolysis (Howard 1991). Aquatic half-lives of 1 to 2 

days have been reported for diquat, because of sorption onto particulates and sediments (National Library of Medicine 

2002). Diquat is a known groundwater contaminant. It has a moderate potential to leach into the groundwater.

37 Segments where water seeps out of the stream and into the ground water, as opposed to segments where seeps and 

springs contribute to stream flow.

38 Has been detected in groundwater. Does not necessarily mean levels have exceeded any established health standard 

or allowance.
195

Fluridone would be applied to ponds, lakes, canals, and reservoirs, but has limited use in flowing water because it 

works through contact maintained over several weeks. Water quality is not degraded when fluridone is used at a 

concentration of less than 20 ppb, and there are no label restrictions against swimming, fishing, or drinking treated 

water (WA Dept of Ecology 2002). Whole-lake treatments using fluridone are possible because the herbicide does 

not cause a rapid plant kill, which would otherwise result in oxygen-depleted water and reduced water quality.

Photodegradation in aquatic systems is an important loss pathway for fluridone (British Crop Protection Council 

and The Royal Society of Chemistry 1994). Fluridone is stable to hydrolysis, volatilizes slowly from water, 

and adsorbs to suspended solids and sediments (EPA 1986, Tomlin 1994, ENSR 2005g). Fluridone has low 

potential to leach to groundwater and is not known to contaminate groundwater. It does have high potential to be 

transported in surface runoff.

Glyphosate, which is registered for aquatic use, would be applied to wetland and emergent aquatic vegetation. 

Strong adsorption to soil particles and organic matter slows microbial degradation, allowing glyphosate to persist 

in aquatic environments in bottom sediments (half-life of 12 days to 10 weeks)(Goldsborough and Brown 1993, 

Extension Toxicology Network 1996a, all cited in Tu et al. 2001).

While glyphosate is very water soluble it is unlikely to enter waters through surface runoff or subsurface flow 

because it binds strongly to soils, except when the soil itself is washed away by runoff; even then, it remains 

bound to soil particles and generally unavailable (Rueppel et al. 1977, Malik et al. 1989, all cited in Tu et al. 

2001). Studies that are more recent found solution-phase glyphosate in 36 percent of 154 stream samples, while 

its degradation product, aminomethylphosphonic acid, was detected in 69 percent of the samples.

Glyphosate may stimulate algal growth at low concentration; Austin et al. (1991) have suggested that this could 

contribute to eutrophication of waterways. However, the study has more implications in streams flowing through 

agricultural and urban areas where glyphosate is shown to be relatively common, although additional phosphates 

from those same areas might mask the effect. The amount of glyphosate expected to reach streams from BLM 

terrestrial applications would be expected to have no noticeable effect on eutrophication. 

Some glyphosate formulations contain polyethoxylated tallow amine (POEA) surfactant, which is substantially 

more toxic to aquatic species than glyphosate or other surfactants that may be used with glyphosate (SERA

2003a). In the Risk Assessment, the toxicity of glyphosate is characterized based on the use of POEA surfactant, 

either in the formulation or added as an adjuvant in a tank mixture (SERA 2003a).

Imazapyr is registered for use in aquatic systems, including brackish and coastal waters, to control emergent, 

floating, and/or riparian and wetland plants. Imazapyr is water soluble and potentially mobile (SERA 2004d). 

Imazapyr is rapidly degraded by sunlight in aquatic solutions, with a half-life of approximately 2 days that 

decreases with increasing pH (Mallipudi et al. 1991, Mangels 1991, all cited in Tu et al. 2001). Imazapyr does not 

appear to degrade in anaerobic systems, such as wetland soil or lake or pond sentiments, and will bind strongly to 

peat (American Cyanamid 1986).

In their literature review of imazapyr, Tu et al. (2001) found no reports of imazapyr contamination in water 

despite its potential for mobility. It is not known to be a groundwater contaminant. Battaglin et al. (2000) stated 

that little is known about its occurrence, fate, or transport in surface water or groundwater. In one study, imazapyr 

(from terrestrial applications) was detected in 4 percent of the 133 samples taken from streams, but was not 

detected in reservoirs or groundwater.

Triclopyr: The two forms of triclopyr, a triethyamine salt and a BEE, behave very differently in water. Both forms 

are used to control woody riparian vegetation. However, only the triethylamine salt form of triclopyr is registered 

Final Environmental Impact Statement, Chapter 4: Water Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 196

for use for selective control of floating, immersed, and submersed aquatic plants. Both forms readily degrade to 

the acid form, which is the active form in plants. No adverse effects on water quality were observed following 

triclopyr triethyamine salt applications in two studies of whole-pond applications in closed systems (no water 

exchange; Petty et al. 2001).

The triethyamine salt form of triclopyr is soluble in water and photodegrades in several hours with adequate 

sunlight. The rate of degradation in water is generally dependent on water temperature, pH, and sediment content.

The BEE form (terrestrial use only, not registered for aquatic application) is not water-soluble and can partition 

into organic materials and be transported to sediments, where it is persistent. Alternatively, bound ester forms can 

degrade through hydrolysis or photolysis to triclopyr acid (Smith 1976 cited in Tu et al. 2001), which will diffuse 

into the water column and continue to degrade (Tu et al. 2001).

Herbicides Used for Terrestrial Vegetation Control

Bromacil is mobile in soil and is a known groundwater contaminant. It can be persistent in most aquatic 

environments because it is stable to hydrolysis, and photodegradation occurs rapidly only under alkaline 

conditions (ENSR 2005b). The environmental hazards section of current product labels includes a groundwater 

advisory warning users not to apply bromacil in areas with permeable soils in order to protect water quality. 

Biodegradation is a major loss mechanism in aerobic and anaerobic aquatic systems. Bromacil is not expected to 

partition to suspend particles or sediments in aquatic systems, but will remain dissolved in the water column and 

has a high potential to leach into the groundwater.

Chlorsulfuron is persistent and mobile in some soils. In aquatic environments, the environmental fate of 

chlorsulfuron is related to pH and temperature. Hydrolysis rates are fastest in acidic waters and slower in more 

alkaline systems (Sarmah and Sabadie 2002). As hydrolysis rates drop, biodegradation becomes the mechanism 

affecting the breakdown of chlorsulfuron. Aquatic dissipation half-lives from 24 days to more than 365 days have 

been reported (ENSR 2005c), with a shorter time reported for flooded soil (47 to 86 days) than anaerobic aquatic 

systems (109 to 263 days; SERA 2004a). Chlorsulfuron is not known to be a groundwater contaminant, but has a 

high potential to leach into the groundwater.

Clopyralid does not appear to bind tightly to soil and will leach under favorable conditions. However, leaching 

and subsequent contamination of groundwater appear to be minimal (SERA 2004b), which is consistent with 

a short-term monitoring study of clopyralid in surface water after an aerial application (Rice et al. 1997a cited 

in SERA 2004b). Clopyralid is not known to be a common groundwater contaminant, and no major off-site 

movement has been documented. Clopyralid does not bind with suspended particles in water; biodegradation 

in aquatic sediments is the main pathway for dissipation. The average half-life of clopyralid in water has been 

measured at 9 and 22 days (Dow AgroSciences 1998).

Dicamba: Because dicamba is mobile in soil, terrestrial application of this herbicide can result in groundwater and 

surface water contamination. Biodegradation is the major mechanism for dicamba degradation in water. Dicamba 

is a known groundwater contaminant, and has a high potential to leach into groundwater. The EPA has set 

health advisory concentration levels for dicamba (e.g., 300 μg/L for 1-day exposures), but has not set maximum 

concentration limits for potable water. A regional study of pesticides in shallow groundwater in Delaware, 

Maryland, and Virginia detected dicamba in groundwater at low concentrations, generally less than 3 μg/L (ppb)

(Koterba et al. 1993).

Diflufenzopyr appears to be soluble, with transportation from surface runoff following application, particularly 

when diflufenzopyr is applied on soils with neutral to alkaline pH. However, based upon proposed uses, fate 
197

characteristics, and model predictions, the EPA does not expect diflufenzopyr to occur in drinking water in 

significant quantities (EPA 1999). Diflufenzopyr is not a known groundwater contaminant.

Biodegradation, photolysis, and hydrolysis are important mechanisms in removing diflufenzopyr from aquatic 

systems. Its half-life is less than 1 month, with hydrolysis and photolysis rates higher in acidic environments. 

The aquatic dissipation half-life for diflufenzopyr is 25 to 26 days in aerobic and 20 days in anaerobic conditions. 

Diflufenzopyr’s expected half-life in small ponds is estimated at 24 days. These factors suggest that diflufenzopyr 

would be removed from an aquatic environment relatively rapidly if contamination occurred (EPA 1999).

Diuron is a known surface water and groundwater contaminant. The U.S. Geological Survey (USGS) National 

Ambient Water Quality Assessment Program analyzed pesticide occurrence and concentrations for major aquifers 

and shallow groundwater in agricultural areas and found diuron in 71 percent of 2,608 samples (Thurman et 

al. 1999). The maximum concentration of diuron was 0.34 ppb (μg/L). The EPA recently placed diuron on the 

drinking water contaminant candidate list39 (EPA 2008a).

In aquatic systems, biodegradation and photodegradation appear to be the primary loss mechanisms for diuron. 

An aquatic biodegradation half-life of 33 days has been reported for aerobic systems. Aquatic dissipation halflives have been reported ranging from 3 to 10 days in anaerobic pond sediment to 177 days in a drainage ditch. 

Diuron is stable to hydrolysis and is unlikely to volatilize from aquatic systems (EPA 2001a). Diuron is expected 

to adsorb to suspended solids and sediments (National Library of Medicine 2002).

At a poorly drained field site along an intermittent stream in Oregon, diuron and its transformation product, 

DCPMU (3-(3,4-dichlorophenyl)-1-methyl-urea), were detected in the stream at a maximum concentration of 

28 μg/L, and were detected in shallow groundwater immediately adjacent to a tributary stream at 2 to 13 μg/L. 

Movement through soil transported the herbicide and its metabolite to the stream, while surface runoff removed 

less than 1 percent of the applied herbicide (Field et al. 2003).

Hexazinone and its degradates persist, are highly mobile, and are readily washed into surface waters. Hexazinone 

has been identified as a groundwater contaminant in seven states. The EPA requires a groundwater advisory on 

all product labels stating that hexazinone must not be used on permeable soils. In areas where irrigation water is 

contaminated with hexazinone or where groundwater discharges to surface water, hexazinone residues in water 

could pose a threat to plants.

In surface water, hexazinone resists photodegradation (Neary et al. 1983 cited in Tu et al. 2001). Hexazinone 

does not bind strongly to particulates or sediments. The main method of degradation is by microorganisms in 

soils. The average half-life of hexazinone in soils and water is 90 days (Tu et al. 2001). Hexazinone has been 

detected in streams near terrestrial application sites up to 30 days after treatment, and reported in runoff up to 6 

months post-treatment in a forestry dissipation study (Neary and Michael 1996; Michael et al. 1999). Neary et al. 

(1984, 1993, all cited in Tu et al. 2001) concluded that hexazinone was diluted in the mainstream flow to very low 

concentrations in forested watersheds.

Imazapic: In aquatic systems, imazapic rapidly photodegrades with a half-life of 1 to 2 days (Tu et al. 2001). 

Since aerobic biodegradation occurs in soils, aerobic biodegradation is likely important in aquatic systems. 

Aquatic dissipation half-lives have been reported from 30 days (water column) to 6.7 years in anaerobic 

sediments (SERA 2004c). Little is known about the occurrence, fate, or transport of imazapic in surface water or 

groundwater (Battaglin et al. 2000). However, according to the herbicide label for Plateau, in which imazapic is 

the active ingredient, it is believed to be a groundwater contaminant (BASF 2008).

39 The other 17 herbicides discussed in this EIS are not on this list.

Final Environmental Impact Statement, Chapter 4: Water Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Metsulfuron methyl is stable to hydrolysis at neutral and alkaline pHs and has a half-life of three weeks in acidic 

systems (Extoxnet 1996b). The persistence of metsulfuron methyl (initial concentration 10 μg/L) was investigated 

using in situ enclosures in a woodland/boreal forest lake, and the half-life was estimated at approximately 29 days 

(Thompson et al. 1992). Metsulfuron methyl is not known to be a groundwater contaminant, although it has a 

high potential to leach into the groundwater.

Picloram can move off site through surface or subsurface runoff, and has been detected in the groundwater of 

11 states (Howard 1991). Picloram does not bind strongly with soil particles and is not degraded rapidly in the 

environment (Tu et al. 2001). Concentrations in runoff have been reported to be great enough to damage crops, 

and could cause damage to certain submerged aquatic plants (Forsyth et al. 1997 cited in Tu et al. 2001).

Picloram may degrade through photolysis, especially in non-turbid and moving water. Woodburn et al. (1989, 

cited in Tu et al. 2001) found that the half-life of picloram in water was 2 to 3 days but the EPA reported it stable 

to hydrolysis and unlikely to degrade in ground water, even over several years (EPA 1995). Maximum picloram 

runoff generally occurs following the first significant rainfall, after which runoff concentrations drop to levels 

that persist up to two years post-application (Scifres et al. 1971, Johnsen 1980, Mayeux et al. 1984, Michael et al. 

1989, all cited in Tu et al. 2001).

Sulfometuron methyl degrades quickly by hydrolysis in acidic water, but is stable in neutral water. Biodegradation 

and photolysis are major loss pathways in aquatic systems, where hydrolysis rates generally are slow. Aquatic 

dissipation half-lives are estimated at 1 to 3 days to 2 months in aerobic systems, and several months in anaerobic 

sediments (Extoxnet 1996c). Sulfometuron methyl is not known to be a groundwater contaminant. In one surface 

water study, sulfometuron methyl was detected in 2 percent of 133 samples taken from streams.

Tebuthiuron persists in the environment and has been found as a groundwater contaminant. It has a low sorption 

to soil. In a study of 71 streams, it was detected in 16 percent of 134 samples but not detected in groundwater 

(Battaglin et al. 2001). Tebuthiuron degrades slowly in aquatic systems.

Routes for Off-Site Movement of Herbicides

Runoff, Drift, Direct Application, and Leaching

The major routes for herbicide contamination of water are runoff from a large rainstorm soon after application, drift 

into streams from spraying, direct application, and leaching through soil into shallow ground water or into a stream.

Runoff

Monitoring studies and fate and transport research often find low, but detectable levels of herbicides concurrent 

with or immediately after (1) herbicide application and (2) the first or the first few rain-induced runoff events after 

application (Berg 2004:3)40.

Berg reported that herbicide applied in or along dry ephemeral or intermittent stream channels may enter streams 

through runoff if a large rainstorm occurred soon after treatment. This risk is minimized if intermittent and 

ephemeral channels are buffered. If a large rainstorm occurs after herbicide application, sediment contaminated 

40 Many or all of the referenced studies were broadcast forest and rangeland treatments, and they were not randomly 

selected. The point of the reference is not that herbicides “often” enter streams, but to identify the two most likely times 

of that entry if it is to occur at all. 
199

by herbicide could be carried into streams. As most herbicide application occurs in the spring through the fall, 

during the dryer season, the probability of a large rainstorm soon after application of herbicides is low at any 

particular site.

Berg’s (2004) compilation of monitoring studies on herbicide treatments with various buffer widths showed that 

any buffer helps lower the concentration of herbicide in streams adjacent to treatment areas. In California buffers 

between 25 and 200 feet generally resulted in no detectable concentrations of herbicide in monitored streams with 

detection limits of 1-3 mg/m3 (ppb) (Berg 2004).

In South Carolina, ground applications of the herbicides imazapyr, picloram and triclopyr had no detectable 

concentrations of herbicide in monitored streams with buffers of 30 meters (~100 feet) (USDA 2003a). No 

detection limits were given.

The USGS in partnership with the Oregon Department of Transportation studied runoff of herbicides along roads 

(similar to treatment of native and other non-invasive vegetation that would be permitted under Alternatives 4 

and 5) (Wood 2001). The study was conducted on runoff associated with several herbicides (Krovar (diuron and 

bromacil), sulfometuron methyl, and glyphosate) along a road in western Oregon simulating rainfall at 1/3 inches 

an hour at 1, 7 and 14 days after treatment. Samples collected at the shoulder of the road had concentrations of 

372-6132 μg/l of diuron the first day after application, and from 23 to 28 μg/l two weeks later. Concentrations of 

glyphosate were similar at 323-736 μg/l the first day after application and 16-41 μg/l two weeks after application. 

Sulfometuron methyl had the lowest concentration consistent with its lower application rate. Concentrations 

ranged from 119-253 μg/l the day after application and from 10-15 μg/l two weeks later. In the fall, the road 

was again sprayed and the ditch line of the road was checked during natural rainstorms for three months. 

Sulfometuron methyl was found in concentrations of 0.1 to 1 μg/l along the shoulder and from 0.3 to 0.1 μg/l in 

the ditch line but was below detectable limits in the stream. Glyphosate was not found at the shoulder, ditch line, 

or stream. This study indicates that the greatest risk of herbicides moving off site is from large storms soon after 

herbicide application. In addition, this study also indicates that 

diuron and sulfometuron methyl may persist in the environment 

as they were above detectable limits along the shoulder of the 

road the entire duration (three months) of the study.

Standard Operating Procedures require a minimum 10-foot 

stream buffer for hand treatments of upland labeled herbicides 

near a stream, 25-foot buffer for broadcast spray from a truck, 

and 100-foot buffer for aerial applications (Appendix 2, Wetland 

and Riparian Areas).

A summary of selected herbicide parameters affecting the 

potential for off-site movement is presented in Table 3-1. 

Herbicide persistence in water is presented on Table 4-17. 

Persistence (longevity in the environment), soil adsorption 

(how well it binds to soils) and solubility (how well it dissolves 

in water) are three properties of herbicides that affect their 

likelihood to move offsite.

Drift

Soil Erosion: Wind erosion can carry herbicide to streams on 

soil particles. Soil movement is heavily dependent on wind 

speed, topography, and surface cover on the soil. To estimate 

potential transport by wind erosion, the Risk Assessments 

Table 4-17. Herbicide Persistence in Water

Herbicide Persistence

Aquatic Use Herbicides 

2,4-D Moderate 

Diquat High 

Fluridone Low 

Glyphosate Moderate 

Imazapyr Moderate 

Triclopyr TEA Moderate

Terrestrial Use Herbicides 

Bromacil Moderate 

Chlorsulfuron Moderate 

Clopyralid Moderate 

Dicamba Moderate 

Diflufenzopyr Low 

Diuron Moderate 

Hexazinone High 

Imazapic High 

Metsulfuron methyl Moderate 

Picloram Moderate 

Sulfometuron methyl Low 

Tebuthiuron High 

Triclopyr BEE Moderate

Source: Vogue et al. (1994) 

Final Environmental Impact Statement, Chapter 4: Water Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 200

used average soil losses ranging from 1 to 10 tons per hectare per year. For a given herbicide, model-estimated 

transport by wind erosion was far less than off site movement of herbicide associated with surface runoff on clay 

soils, and similar to off-site losses associated with drift at a distance of 500 feet or more from the application site. 

Movement of herbicides from wind erosion would be expected to be minimal in western Oregon due to the dense 

groundcover and more limited treatment sites. It would be expected to be more important in drier areas east of the 

Cascades in larger treatment areas. See Soil Resources for additional information of wind erosion risks.

Aerial Application: Aerial application is the least targeted type of application and is the method of application 

for approximately 7 percent of the herbicide used on BLM land in Oregon (see the Herbicide Treatment Methods 

section in Chapter 3). Drift from aerial applications is the process most likely to result in herbicides getting onto 

non-target areas such as stream channels. This is primarily dependent upon the elevation of the spray nozzle, 

droplet size and air movement. The smaller the droplet, the longer it stays suspended and the farther it can travel.

Spray drift can be reduced by increasing droplet size since wind will move large droplets less than small droplets 

(Table 4-18). Droplet size can be increased by: 1) reducing spray pressure; 2) increasing nozzle orifice size; 

3) using special drift reduction nozzles; 4) using additives that increase spray viscosity; and, 5) using rearward 

nozzle orientation in aircraft.

Commercial drift reduction agents are available that are designed to reduce drift beyond the capabilities of the 

determinants described above. These products create larger and more cohesive droplets that are less apt to break 

into small particles as they fall through the air. They reduce the percentage of smaller, lighter particles, which are 

most apt to drift. Standard Operating Procedures for air quality provide techniques for controlling drift, including 

specifying selection of equipment that produces 200-800-micron diameter droplets.

Table 4-18. Drift Distance Versus Drop Diameter (NDSU 1993)

Droplet Diameter (microns) Type of Droplet Airborne Time

Lateral Distance Traveled in 

10 foot height & 3 mph wind 

speed

5 Fog 66 minutes 3 miles

20 Very Fine Spray 4.2 minutes 1,100 feet

100 Fine Spray 10 seconds 44 feet

240 Medium Spray 6 seconds 28 feet

400 Coarse Spray 2 seconds 8.5 feet

1,000 Fine Rain 1 second 4.7 feet

The Washington State Department of Ecology and Oregon Department of Forestry have monitored aerial 

application of herbicides in forest settings41. The purpose of both studies was to look at the effectiveness of buffers 

protecting water quality in streams within herbicide treatment areas. The Washington study looked at many factors 

in addition to stream buffers that affected the concentration of herbicides in streams within treatment areas.

The Washington study collected herbicide samples at seven sites on small streams (Rashin and Graber 1993). 

Buffers were 50 feet on flowing streams and no buffers on small stream channels assumed to be dry. Peak 

herbicide concentrations ranged between 0.2 and 7.55 μg/l. Maximum 24 hour averages were between 0.13 and 

3.25 μg/l. Runoff samples collected at four sites 2 to 24 days after application had concentrations between 0.17 

and 2.49 μg/l.

41 Such an application would be rare under alternatives examined in this EIS. The alternatives do not include treatments 

with timber production objectives.
201

The Washington study attributed the majority of herbicide introduction in buffered streams to swath displacement, 

drift, and secondary contribution from overspray of small stream channels mistakenly assumed to be dry. This 

study recommended buffers of between 15 to 25 meters (45-75 feet) for upwind streams and 75 to 90 meters (225-

270 feet) for streams downwind of applications.

The State of Oregon requires buffers of 60 feet for aerial application of herbicides near fish bearing streams or 

streams used for domestic water supplies. For the Oregon study, two streams outside this category also received 

60-foot buffers (actual on the ground buffers ranged from 60 to 100 feet). Most of the samples (21 sites, and 105 

post spray samples) had a detection limit of 1 μg/l. None of these samples had concentrations at detectable limits. 

Five sites (25 samples) had detection limits of 0.04 to 0.5 μg/l. Most samples were still below detectable limits, 

but 7 of the 25 samples tested between 0.9 and 0.56 μg/l (Dent and Robben 2000).

All aerial applications of herbicides will comply with EPA label restrictions and State regulations. Standard 

Operating Procedures applicable to all alternatives (Appendix 2, Wetland and Riparian Areas) require a minimum 

of 100-foot stream buffers for aerial sprays to reduce drift to streams.

Direct Application

Spray Monitoring: Washington State monitoring reports were looked at for 2003-2006 (WA Dept of Ecology 

2003-2006). Many sites showed no detection after spraying. The site with the highest detection was a small 

pond where 1/3 acres of parrot’s feather was sprayed with glyphosate. The results were 343 μg/l one hour after 

treatment and 53 μg/l 24 hours later. This is under the threshold for glyphosate in potable water and under the 500 

μg/l used for acute toxicity index for fish.

Lakes, Reservoirs, and Wetlands: Herbicides affect lakes and wetlands differently than streams. Dilution by 

flow or tributary inflow is generally less effective in lakes. Dilution is partially a function of lake size, but 

dilution could be rapid in small lakes in rare instances where they have large water contributing areas. Decreases 

in herbicide concentration in lakes, ponds, and other lentic water bodies are largely a function of chemical 

and biological degradation processes rather than of dilution. Evaporation of water from a lake’s surface can 

concentrate chemical constituents. As vegetation within water dies, the oxygen level within the lake can decrease.

Injection Monitoring: Knotweed stem-injection sites were also monitored by Washington States Department of 

Ecology. Three sites had no detectable concentrations in the water one hour or 24 hours after injection. The two 

sites with detectable concentrations were under the threshold for potable water (Table 4-19).

Accidental Spill: Concentrations of herbicides in streams as a result of an accidental spill depend on the rate of 

application and the streams’ ratio of surface area to volume. The persistence of the herbicide in water depends on 

the length of stream where the accidental spill took place, velocity of stream flow, and hydrologic characteristics 

of the stream channel. The concentration of herbicides would decrease rapidly down-stream because of dilution 

and interactions with physical and biological properties of the stream system (Norris et al. 1991). An herbicide 

transportation and handling plan is required for all herbicide control projects. This plan would address spill 

prevention and containment.

Table 4-19. Glyphosate Concentration in Washington Streams 1 Hour and 24 Hours After Injection

Year 1 hour (μg/l) 24 hour (μg/l)

2004 50 10

2005 12.1 3.8

2005 ND ND

2006 ND ND

2006 ND ND

ND = Not Detected

Final Environmental Impact Statement, Chapter 4: Water Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 202

Leaching

Groundwater: Groundwater contaminated from surface water treatments is generally minimal for many herbicides 

because decomposition of herbicide by microbial action and other processes is quicker than the time taken for 

herbicide-laden water to move from surface waters to groundwater (Berg 2004). Travel time to groundwater 

decreases as the depth to groundwater decreases, and generally, the depth to groundwater is least in spring and 

greatest in late summer. If spring rains come shortly after herbicide application and the water table is close to the 

surface, a greater potential for groundwater contamination exists (Mahler et al. 2002).

The shallower the depth to groundwater, the less soil there will be to act as a filter and the less chance for 

degradation or adsorption of herbicides (Berg 2004). In humid regions, groundwater may be only a few feet 

below the surface of the soil. If rainfall is high and soils are permeable, water carrying dissolved herbicides 

may take only a few days to percolate downward to groundwater. In arid regions, groundwater may lie several 

hundred feet below the soil surface, and leaching of herbicides to groundwater may be a much slower process 

(Alabama Cooperative Extension 1999 cited in Berg 2004).

The potential for herbicides reaching groundwater to result in adverse effects depends upon concentration level 

and subsequent human and environmental exposure. Detections alone, while potentially indicative of a need 

for controls, do not necessarily indicate a detectable effect (see Maximum Herbicide Concentration Allowed in 

Potable Water; Table 4-16).

Lakes Reservoirs and Wetlands: Herbicides affect lakes and wetlands differently than streams. Dilution by flow or 

tributary inflow is generally less effective in lakes. Dilution is partially a function of lake size, but dilution could 

be rapid in small lakes in rare instances where they have large water contributing areas. Decreases in herbicide 

concentration in lakes, ponds, and other lentic water bodies are largely a function of chemical and biological 

degradation processes rather than of dilution. Evaporation of water from a lake’s surface can concentrate 

herbicide constituents. As vegetation within water dies, the oxygen level within the lake can decrease.

Accidental Spill: Concentrations of herbicides in streams as a result of an accidental spill depend on the rate of 

application and the streams’ ratio of surface area to volume. The persistence of the herbicide in water depends on 

the length of stream where the accidental spill took place, velocity of stream flow, and hydrologic characteristics 

of the stream channel. The concentration of herbicides would decrease rapidly down-stream because of dilution 

and interactions with physical and biological properties of the stream system (Norris et al. 1991). An herbicide 

transportation and handling plan is a project requirement. This plan would address spill prevention and 

containment.

Effect of Invasive Plants on Water Resources

Invasive plants can create or exacerbate conditions that reduce water quality. Reed canarygrass is a common 

invader of wetlands and riparian areas. Purple loosestrife is another species that occupies stream banks, canals, 

and shallow ponds. Many other species can occupy either riparian or upland habitat. For example, herb Robert, 

Himalayan blackberry and scotch broom can all occupy either upland or riparian habitat. Many invasive plants 

grow quickly and densely allowing them to out-compete native vegetation. Invasive plants are difficult to control 

in riparian areas as they thrive in the moist environment. Invasive plants can affect water quality by affecting 

bank stability, sediment, stream temperature, dissolved oxygen, and pH (USDA 2005a), and can increase runoff 

and increase peak flows (Lacey et al. 1989 cited in Dewey et al. 1995:622). See the Wetland and Riparian Areas

section for additional information.
203

Japanese knotweed is one of the invasive plants that has the potential to affect stream functioning. Japanese 

knotweed is a creeping perennial that grows in the spring and summer and dies back with the first hard frost. 

Knotweed resprouts following cutting, mowing, and digging. Japanese knotweed has poor bank holding capacity, 

which leads to more bank erosion and sedimentation of streams in high winter flows (USDA 2005a). While 

knotweed may provide some shade, native streamside hardwoods and conifers are much taller and provide 

more dense shade, so knotweed-dominated areas may be associated with higher water temperatures than areas 

with native forest communities. Knotweed spreads rapidly in flood prone areas such as the Pacific Northwest. 

Knotweeds tolerate a wide variety of substrates from cobbles to fine soils (Tu and Soll 2004).

Upland invasive plants are also found along streams where they can colonize a range of sites. Himalayan 

blackberry is the most widespread and economically disruptive of all the noxious weeds in western Oregon 

(ODA 2008). It aggressively displaces native plant species and dominates lower elevation riparian habitats. Like 

knotweed, it has poor bank-holding capacity, leading to erosion and altered stream channel morphology. 

Total vegetative cover can be reduced on weed-infested sites where strong invaders outcompete native vegetation. 

Diffuse and spotted knapweeds are found along many eastern Oregon streams. Weed infested soil has been shown 

to be more susceptible to erosion than soil occupied by native grass species (Lacey et al. 1989). Soil erosion in 

a simulated rainfall test more than doubled in spotted knapweed-dominated rangeland areas when compared to 

natural bunchgrass/forb grasslands (Lacey et al. 1989).

Eastern Oregon is losing shrubland due to expansion of western juniper. The integrity and extent of riparian 

vegetation have changed and been fragmented in response to forest conversion and disturbance (Miller et al. 

2005). Western juniper removes water from most of the soil profile, decreasing discharge to streams. Reducing 

western juniper cover has been shown to increase understory vegetation and infiltration and reduce erosion (Miller 

et al. 2005, Pierson et al. 2007, Peterson and Stringham 2008).

Medusahead, knapweeds, and cheatgrass can lead to shortened fire cycles followed by increased soil erosion and 

stream sedimentation.

In addition to the aquatic emergent species discussed above, lakes and wetlands may have invasive submerged 

species such as Eurasian watermilfoil. These species are becoming common invaders of aquatic ecosystems, 

outcompeting native vegetation. For example, Eurasian watermilfoil was introduced to Oregon coastal lakes 

about 40 years ago (PSU 2000). Eurasian watermilfoil multiplies rapidly and forms canopies over the native 

plants, literally choking out native plants and severely restricting recreational activities. In addition, it degrades 

water quality and fish habitat, accelerates eutrophication (over-abundance of nutrients), and lowers amounts of 

oxygen in the water.

Effects by Alternative

Reference Analysis – No Herbicide Use

This strategy would not use herbicides and therefore would not have the potential to contaminate water with 

herbicides42. Many treatments would occur by other methods: primarily fire, livestock, mechanical, or manual 

treatments (Chapter 3). Fire without herbicides generally needs to be used several years in a row to be effective 

(Tu et al. 2001). Use of fire has potential for increased sediment input to streams depending on if large storms 

occur before other vegetation becomes established. Directed livestock has potential for localized effects to water 

42 BLM waters could still be affected by herbicide use on adjacent lands.

Final Environmental Impact Statement, Chapter 4: Water Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 204

quality if used near a stream. The effects would be increased fecal coliform and increased fine sediment. Effects 

could potentially include trampling of banks affecting the width to depth ratio of the stream. Effectiveness of 

these treatments depends on the species being treated, the timing of treatment, and the size of the infestation. 

This strategy would use directed livestock on 8,800 acres, a threefold increase from the No Action Alternative 

(Alternative 2). Wheeled and tracked mechanical treatments can have similar effects, but are less likely to be near 

the streams. Manual treatments can be effective for small infestations of non-rhizomatous species. When near 

streams, pulling weeds could increase sediment input to streams when compared to the No Action Alternative, but 

pulling and cutting can also increase mulching when plants can be left on site.

Many non-herbicide treatments are not effective with many of the invasive plants. Certain species such as 

knotweeds are not controllable without herbicides. Knotweeds have roots and rhizomes with depths of up to 7 

feet and spread of more than 20 feet from the parent plants (Boersma et al. 2006). Knotweeds are found most 

thickly in western Oregon but are present in small areas in eastern Oregon also.

Invasive plants are typically less effective at maintaining stable stream banks than native plant species. Most 

invasive plants also provide less stream shading than native hardwoods and conifers. Invasive plants are expected 

to spread at the fastest rate (14 percent), and ultimately infest more acres, under this strategy.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

The four herbicides used under this alternative include three known groundwater contaminants: picloram, dicamba 

and 2,4-D. Picloram is a high-risk herbicide for aquatic resources but is preferred in many situations because it is 

a selective herbicide that represses reestablishment of target invasive plants. Some of the invasive plants found 

in Oregon are not effectively controlled by the four herbicides available. For example, the four herbicides are 

ineffective at treating saltcedar (Appendix 7: Table A7-1). A mature saltcedar consumes as much as 800 liters of 

water per day -- 10 to 20 times the amount used by native species it tends to replace (Cooperrider 1995).

While glyphosate is available to treat emergent species such as knotweeds and yellow flag iris, no herbicides 

are available to treat submerged plants such as Eurasian watermilfoils and hydrilla. These plants degrade water 

quality by eutropification that can lead to lower oxygen levels in the water. Noxious weeds are expected to 

continue to spread at approximately 12 percent per year under this alternative, and infest about 1/3 of BLM lands 

in 15 years.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

This alternative would use herbicides on an additional 13,600 acres, (mostly east of the Cascades), but because the 

additional herbicides are effective at smaller doses, total pounds of herbicide would go down 35 percent (at the typical 

rate). Use of the four herbicides presently used would go down as other herbicides were used instead. For example, 

clopyralid (low risk to aquatic ecosystems) can frequently be substituted for the use of picloram. However, the greater 

number of acres treated increases exposure, adding risk of both surface and groundwater contamination by herbicides. 

Standard Operating Procedures require that areas with shallow groundwater and areas of groundwater-surface water 

interaction be identified to reduce impacts to groundwater from the application of herbicides.

Three of the additional herbicides in this alternative43 would be used to treat aquatic emergent or submergent plants 

giving this alternative greater potential to treat invasive aquatic plant species than Alternative 2 (No Action). The 1.9 

million fewer infested acres in 15 years than Alternative 2 translates to fewer degraded stream banks, riparian areas, 

and watersheds.

43 Fluridone, imazapyr, and triclopyr
205

Effects of Riparian and Aquatic Treatments: Restoring native plants would improve riparian stability where 

invasive plants like Himalayan blackberries and knotweeds have colonized along stream channels and outcompeted native species. However, invasive plants removal could exacerbate stream instability as well as remove 

stream shading; these effects could last until the native vegetation replaced the treated vegetation; planting is often 

used to shorten this time. BLM policy requires restoration plans under site-specific analysis to account for these 

effects, and prescribe mulching, seeding, and planting as needed to revegetate riparian and other treated areas 

(USDI 2008a:52). Speeding restoration of such management-exposed stream banks with willow planting or other 

measures is common BLM practice.

Imazapyr has an aquatic formulation that is frequently used to control knotweeds and saltcedar. Triclopyr is 

used to control broadleaf species and saltcedar in riparian areas. Removing invasive riparian and aquatic plants 

can result in improved water quality where blooms of invasive plants lead to low dissolved oxygen, and where 

invasive plants within riparian areas have lead to increased erosion and sedimentation. Monitoring data for 

emergent treatments show that the amount of herbicide entering water from treatments is generally below levels 

of concern (LOC) for potentially exposed aquatic organisms.

Fluridone is an aquatic herbicide available to control submerged aquatics including Eurasian watermilfoils and 

hydrilla. This herbicide can only be used in still waters such as ponds and lakes. It is proposed for 100 acres east 

of the Cascades and 200 west of the Cascades. In Washington, it is considered effective at controlling Eurasian 

watermilfoil without affecting drinking water quality or recreation (WA Dept of Ecology 2002). Fluridone is slow 

acting and is used at low concentrations on both submergent and emergent plants. As the plants die off slowly, 

there is not a large concentration of decaying organic matter added to the water at one time so it is less likely to 

deoxygenate the water than other aquatic herbicides.

There is low risk to drinking water from treatment with imazapyr, glyphosate, triclopyr, or fluridone even in the 

case of accidental spills. 2,4-D is considered moderate risk for drinking water under accidental spill scenarios 

(see Human Health and Safety section in this Chapter).

Effects of Upland Treatments: Buffers are effective at reducing the movement of herbicide to streams (Berg 

2004, Dent and Robben 2000, Rashin and Graber 1993). The potential for impacts from herbicide drift would 

be reduced by the Standard Operating Procedure requiring minimum 10-foot hand spray, 25-foot vehicle, and 

100 foot aerial buffers between treatment areas and water bodies (Appendix 2). Standard Operating Procedures 

require that buffers based on herbicide properties and site-specific data would be developed using the Ecological 

Risk Assessments for project level analysis. Parameters to be considered include the herbicide physical properties 

and off-site movement potential shown on Table 4-17.

Roads often parallel streams or have stream crossings. Roads can act as extensions of stream networks with 

roadside ditches having low but measurable herbicide concentrations months after treatment (Wood 2001). Since 

vehicles are a major invasive weed vector, a high percentage of invasive weed treatments are along roadsides. 

Herbicides used in these areas could reach streams even when buffers to the actual stream are applied. Standard 

Operating Procedures such as stream buffers reduce potential impacts to water quality from herbicide applications 

but do not specifically address ditches. Overall exposure would be increased under this alternative compared to 

Alternative 2 (No Action) because more acres would be treated, but the total pounds would be lower, especially 

for those herbicides of highest concern to water quality. 

This alternative would add about 7,000 acres of additional prescribed fire treatments to the 5,100 acres found under 

Alternative 2 (No Action), increasing the potential for storms to deliver sediments to streams. These treatments 

are in a dryer part of Oregon where many stream channels run seasonally, so few perennial streams are likely to be 

adversely affected by treatments. Where perennial streams are affected, those effects would be temporary; longterm effects would be positive as vegetation provides riparian shading and reduces runoff and erosion.

Final Environmental Impact Statement, Chapter 4: Water Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 206

Local and temporary increases in stream flows could occur in areas where large acreages of a monoculture such as 

cheatgrass, medusahead, starthistle, or knapweed would be treated with herbicides or prescribed fire. This would 

typically last one season or until native vegetation became reestablished.

Hexazinone is only proposed for 200 acres but is persistent and mobile. It has been reported in runoff up to six 

months post treatment (Tu et al. 2001). Hexazinone is considered a high risk for groundwater contamination.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

Alternative 4 would treat the same noxious weeds as Alternative 3 and would add treatments of native and other 

non-invasive vegetation on rights-of-way, administrative and recreation sites, and permit habitat restoration 

specified in Conservation Strategies for Special Status species. This Alternative would permit the use of more 

types of herbicides and would be expected to treat more acres with herbicides and use more pounds of herbicides, 

when compared with Alternative 3. The additional acres treated would increase the risk of contamination of 

domestic water sources (although as with other uses, required buffers and other Standard Operating Procedures 

would minimize this risk). The three added herbicides (bromacil, diuron, and tebuthiuron east of the Cascades, 

and an estimated 100 acres of diuron west of the Cascades) are all known groundwater contaminants. The same 

Standard Operating Procedures discussed under Alternative 3 would be used to minimize risks.

Effects of Riparian and Aquatic Treatments: Riparian and aquatic treatments have the same advantages and risks 

as discussed under Alternative 3.

Effects of Upland Treatments: The treatment of invasive plants has the same advantages and risks as Alternative 

3. The treatment of native and other non-invasive vegetation would add treatment of 13,000 acres east of the 

Cascades and 2,100 acres west of the Cascades. This alternative would treat rights-of-way, replacing mowing 

in an assumed 1 to 1 ratio. As more roads and rights-of-way (and thus more ditch lines) are treated, there is 

more potential for herbicide to enter water. Buffers would apply at stream crossings to minimize the amount 

of herbicide entering streams. The added herbicides, bromacil, diuron, and tebuthiuron, are commonly used 

for control of vegetation along roads and rights-of-way on non-BLM lands. These are all persistent and mobile 

herbicides. Standard Operating Procedures include buffers to minimize impacts to water quality and the 

requirement under site-specific projects to minimize impacts to water quality.

Diuron was the 13th most commonly used pesticide in the State of Oregon in 2008 (Table 4-1). Diuron was found 

at low concentrations; less than 1 microgram per liter, which is 10 to 100 times less than the EPA benchmark 

for fish and invertebrates. There is no numeric water quality criteria established for diuron at this time (ODEQ 

2008). BLM would use diuron only under Alternatives 4 and 5. The estimated use in western Oregon would 

be approximately 100 acres (800 acres for the whole state), a small fraction of the acres treated in Oregon (see 

Table 4-1). Standard Operating Procedures and PEIS Mitigation Measures include minimum buffers for use 

of upland labeled herbicides near water based on application type (Appendix 2). In addition, for project level 

analysis, Standard Operating Procedures include the guidance to develop further refined buffer widths based on 

herbicide properties and site-specific conditions to minimize impacts to water quality. Buffers limit the transport 

of herbicide from upland treatments to water (Berg 2004, Dent and Robben 2000, Rashin and Graber 1993).

Where western juniper is removed as part of a Conservation Strategy-prescribed treatment, there is a potential to 

increase stream flows, benefiting aquatic organisms and increasing riparian vegetation (Miller et al. 2005, Pierson 

et al. 2007, Peterson and Stringham 2008). Improved riparian condition improves resiliency to storm events.
207

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Alternative 5 would make 18 herbicides available for a full range of vegetation management objectives except 

livestock forage and timber production. The effects would be about the same as those discussed under Alternative 

4 (Proposed Action) except as follows. Approximately 5,000 more acres would be treated with herbicides, with 

most of the increase used for habitat improvement east of the Cascades. This alternative would add diquat for 

treatment of aquatic plants. This alternative would lower the noxious weed spread rate to 6 percent, the same 

as Alternative 4. The additional acres treated would slightly increase the risk of contamination of human water 

sources; most of the risk is expected east of the Cascades. Standard Operating Procedures discussed under 

Alternative 3 and used under this alternative also to minimize risk to human water sources.

Effects of Riparian and Aquatic Treatments: Effects of treatment of emergent and aquatic invasive plants would 

be similar to Alternative 4 (Proposed Action) with the addition of one aquatic herbicide. Diquat is a known 

groundwater contaminant and has a maximum concentration level of 0.20 μg/l for potable water. Diquat is 

an aquatic herbicide with potential to deoxygenate water if large areas are treated due to plant decomposition. 

However, only 100 acres of treatment are proposed with this herbicide east and west of the Cascades. This is 

0.25 percent of treatments east of the Cascades and 1 percent of treatments west of the Cascades. This herbicide 

is proposed for use in large part because it is the only herbicide available to BLM that will control giant salvinia. 

Giant salvinia is not known to occur in Oregon at this time, and current climate conditions in Oregon appear to be 

outside of its ecological amplitude.

Effects of Upland Treatments: The higher number of acres treated would add to the risk of herbicide impacting 

water quality although due to Standard Operating Procedures such as stream buffers, the risk is minimized. Most 

of the 5,000 additional treatment acres under this alternative would be upland treatments, and could use any of the 

18 herbicides registered for terrestrial use.

Additional acres of western juniper treatment are likely to be controlled under this alternative as a habitat 

improvement treatment, with a potential for localized increases in flow where large acreages are treated within a 

single drainage.

Summary of Effects to Water Quality

With Standard Operating Procedures and PEIS Mitigation Measures the same for all alternatives, the differences 

between alternatives for water quality are dependent on the acres treated and the pounds of herbicides applied, 

balancing the treatment of invasive plants. Alternatives 4 (Proposed Action) and 5 are higher risk for water 

quality due to the pounds of herbicide used and the fact that they treat recreation areas which are frequently found 

near water. Alternative 3 would treat more acres than Alternative 2 (No Action) but would use fewer pounds of 

herbicide, and would treat fewer acres with moderate risk herbicides. Therefore, Alternative 3 is likely to have the 

least risk to water quality from the use of herbicides.

Cumulative Effects

Herbicide use occurs on other Federal, State, and County lands, private forestry lands, rangeland, agricultural 

land, utility corridors, and road rights-of-way. Table 4-1 compares the pounds of each herbicide projected to 

be applied under the BLM Proposed Action (Alternative 4) with the amount of those herbicides used on all 

ownerships statewide. BLM manages 25 percent of the land in Oregon and would use less than 1 percent of 

the herbicides under the Proposed Action compared to the total use of these herbicides in Oregon. The use of 

herbicides by BLM is usually a small amount of the total use in any large watershed given the mixed ownerships.

Final Environmental Impact Statement, Chapter 4: Water Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 208

Washington State stream monitoring following application of herbicides to treat emergent vegetation (Table 

4-19) has resulted in no detection or levels below drinking water standards (Table 4-16) and therefore no 

increase in cumulative effects. In 2000, the Oregon Department of Forestry completed a study of aerial pesticide 

applications, indicating that water resources, aquatic organisms, and riparian management areas were being 

adequately protected under current rules (which are less strenuous than the Standard Operating Procedures 

associated with this EIS) (Dent and Robben 2000).

In addition, many of the added herbicides pose fewer risks to humans, fish, and wildlife than those available under 

the No Action Alternative (Alternative 2). The BLM’s contribution to downstream effects is minimized with 

Standard Operating Procedure implementation such as required buffer widths and limits on application methods. 

Use of additional project-specific mitigation measures would limit the extent and duration of direct and indirect 

impacts and, therefore, the addition of cumulative effects.

Treatment of invasive plants can improve water quality where riparian function improves and where vegetation 

or stabilized banks provide shading. Alternatives 3-5 target the same acres of invasive plants while Alternatives 

4-5 treat additional native and other non-invasive vegetation (and incidentally control additional noxious weeds; 

see the Noxious Weeds and other Invasive Plants section earlier in this Chapter). With additional acres treated, 

particularly along roads, there is an increased potential for off-site movement of herbicide to affect water quality.

Wetlands and Riparian Areas

Affected Environment

Wetlands are generally defined as areas inundated or saturated by surface water or groundwater at a frequency 

and duration sufficient to support, and under normal circumstances do support, a prevalence of vegetation that is 

typically adapted for life in saturated soil. Wetlands include bogs, marshes, wet meadows, estuaries, and swamps. 

To be designated as a wetland, the 1987 U.S. Army Corps of Engineers Wetland Delineation Manual requires:

• The substrate is predominately undrained hydric soil, or the soil possesses characteristics that are 

associated with reducing soil conditions;

• The area is inundated either permanently or periodically at a mean water depth of less than 6.6 feet or the 

soil is saturated to the surface at some time during the growing season of the prevalent vegetation; and,

• The land supports predominately hydrophytes. Hydrophytes are macrophytic plants with the ability to 

grow in water or on a substrate that is at least periodically deficient in oxygen (anaerobic) as a result of 

excessive water content and depleted soil oxygen levels (Environmental Laboratory 1987).

In Oregon, the BLM manages 153,814 acres of wetlands; over half of the BLM wetlands found in the lower 48 

states and about one percent of the BLM lands in Oregon. Ninety-three percent are considered to be functioning 

properly; the remaining seven percent have not been inventoried (USDI 2007b). The BLM defines properly 

functioning wetlands as those that (Prichard et al. 2003): 

1) support adequate vegetation, landform, or debris to dissipate energies associated with wind action, wave 

action, and overland flow from adjacent sites, thereby reducing erosion and improving water quality; 

2) filter sediment and aid floodplain development; 

3) improve floodwater retention and groundwater recharge; 

4) develop root masses that stabilize islands and shoreline features against cutting action; 
209

Final Environmental Impact Statement, Chapter 4: Wetlands and Riparian Areas

5) restrict water percolation; 

6) develop diverse ponding characteristics to provide the habitat and the water depth, duration, and 

temperature necessary for fish production, water bird breeding, and other uses; and, 

7) support greater biodiversity. 

Wetlands partially on BLM lands range from coastal estuaries to isolated marshes within the Sagebrush Steppe 

Biome experiencing less than ten inches of precipitation per year.

Riparian Areas occur adjacent to streams and rivers and are directly influenced by water. A riparian community 

is characterized by certain types of vegetation, soils, hydrology, and fauna and requires free or unbound water or 

conditions more moist than that normally found in the area.

BLM lands in Oregon contain just over 8,000 acres of riparian areas, with 38 percent functioning properly, 34 

percent functioning at risk, 2 percent non-functional, and 26 percent uninventoried (USDI 2007b:Table 2-2). 

The benefits of these areas far exceed their relatively small acreage. The functions of wetland and riparian areas 

include water purification, stream shading, flood attenuation, shoreline stabilization, groundwater recharge, 

and habitat for aquatic, semi-aquatic, and terrestrial plants and animals (Lewis et al. 2003). In semi-arid areas 

east of the Cascades, even intermittent streams provide opportunities for increased native vegetation and the 

associated benefits.

As indicated in the East Side Riparian Biome section earlier in this Chapter (and applicable to drier parts of 

Oregon west of the Cascades as well, such as in the Siskiyou Biome), there are physical, chemical, and biological 

linkages or interrelationships that are unique to wetland and riparian areas east of the Cascades and in the 

Siskiyou Biome. Soils within riparian areas typically contain more organic matter, clay particles, and of course 

moisture than adjacent uplands, generally allowing them to hold and process herbicides more efficiently than 

upland soils. Organic matter in riparian soils can also help promote water quality benefits such as denitrification 

(EPA 2005c). Riparian vegetation is typically more diverse and more abundant than, and is easily distinguished 

from, that in adjacent uplands. Topography helps accentuate a rapid decline in soil moisture as one moves away 

from most streams.

Unlike the moist Western Forest Biome where plant production may not change significantly from riparian 

to upland, the limited availability of water in the remainder of the State causes native plant production to be 

concentrated in and around wetland and riparian areas. Probably the most important characteristic of semiarid wetlands and their buffers is the increased diversity and productivity of native deciduous trees and shrubs 

as compared to surrounding semi-arid grasslands (City of Boulder 2007). Riparian areas tend to be one of 

the few locations in semi-arid landscapes that possess dense, multilayered vegetation including trees, shrubs, 

and herbaceous species which provide important cover for terrestrial wildlife. Abundant leaf litter from the 

cottonwoods and other woody species provides food for aquatic insects. Cottonwoods and other riparian trees 

shade streams and provide large woody debris that dissipates stream energy and supplies cover for fish.

The Warner Wetlands near Hart Mountain in Lake County, for example, is critical to nesting waterfowl and other 

wildlife, and is infested with perennial pepperweed. It is BLM’s biggest cooperative weed control project with 

Oregon Department of Agriculture. Annual nesting success of ducks in this wetland has been positively correlated 

with the success of perennial pepperweed control. Remnant native Willamette Prairie vegetation, including seven 

Federally Listed species (6 plants and 1 butterfly), is threatened by invasive plants in the West Eugene Wetlands. 

Non-herbicide methods of control are relatively ineffective against invasive plants in wetlands in part because of 

difficulty working effectively on wet and saturated soils.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 210

All wetlands and riparian areas are susceptible to invasive plants. High flow events as well as fire, wind, and 

human activities create disturbances invasive plants can exploit. Birds, recreationists, stream flow, wind, and 

other vectors readily supply the seed. Aquatic invasive plants such as reed canary grass, purple loosestrife, 

saltcedar, and Japanese knotweed grow in water or along banks, displace native plants, and adversely affect 

riparian functions (see Water Resources). Japanese knotweed has poor bank holding capacity, which leads to 

more bank erosion and sedimentation of streams in high winter flows (USDA 2005a). While knotweed may 

provide some shade, native streamside hardwoods are much taller and provide more dense shade, so knotweeddominated areas may be associated with higher water temperatures than areas with native forest communities. 

Knotweed spreads rapidly downstream in flood prone areas such as the Pacific Northwest. Knotweeds tolerate a 

wide variety of substrates from cobbles to rich soils (Tu and Soll 2004).

Purple loosestrife is an aggressive invasive plant that outcompetes native vegetation and forms monocultures in 

the infested wetlands. It grows quickly and spreads by roots, stem fragments, or seeds (Boersma et al. 2006:76). 

On smaller streams, purple loosestrife can increase fine sediment deposition, smothering spawning gravels, and 

decreasing channel capacity (USDA 2005a).

Reed canarygrass is extremely aggressive and often forms persistent monocultures in wetlands and riparian areas. 

Infestations threaten the diversity of these areas, since the plant chokes out desirable plants and grows too densely 

to provide adequate cover for small mammals and waterfowl. Where the reed canarygrass grows in water, it can 

slow the movement of water carrying sediment and lead to increased siltation along drainage ditches and streams. 

Salmon spawning streams can have the gravels covered with silt and no longer be suitable for spawning. Once 

established, reed canarygrass is difficult to control because it spreads rapidly by rhizomes (WA Dept of Ecology b).

Upland species are also found along streams where they can colonize a range of sites. Himalayan blackberry is 

the most widespread and economically disruptive of all the noxious weeds in western Oregon. It aggressively 

displaces native plant species and dominates riparian habitats (ODA 2008). Himalayan blackberry loses its leaves 

in the winter and the bare canes do not protect stream banks from rain-splash or high flow erosion in the same 

manner as native trees or wetland vegetation. The shallow root system does not protect the banks from being 

undercut. Once undercut, the stream banks collapse under the weight of the brambles; widening the channel. 

Steep banks, high erosion rates, and dense summer shade from the blackberry thickets make it more difficult for 

native vegetation to re-colonize the exposed banks (Bennett 2006).

Eastern Oregon has experienced a recent five-fold spread of native western juniper that has adversely affected 

riparian areas by decreasing groundwater available to small and intermittent streams. Stream flows have 

decreased and many riparian miles have been lost in the past 50 years due to the additional water used by 

encroaching western junipers. Removal of these western junipers has been the focus of several projects in the 

Prineville area as a means to return streams to their historic flows.

Environmental Consequences

Wetland and riparian area species and function can potentially be adversely affected by herbicide use, by nonherbicide invasive weed control measures, and by the increase of noxious weeds and other invasive plants. As 

with the other resources discussed in this Chapter, the various alternatives can potentially increase the risk in one 

or more of these categories while decreasing the risk in other(s).
211

Effects Common to All Alternatives

Fate of Herbicides in Wetlands and Riparian Areas

Herbicide drift, runoff, soil erosion, or ground water leaching could affect wetlands and riparian areas. The 

risk would be related to the amount, selectivity, persistence of the herbicide, application methods, timing of 

the application in relation to climatic conditions, and the plant species present. Accidental spills or unintended 

applications to wetlands and riparian areas would be the greatest risk and have the most impact. Herbicides 

dissipate in wetlands and riparian areas by water transport, chemical or biological degradation, and adsorption and 

immobilization in soils. Herbicides applied upland and adjacent to wetlands but moving into the wetland may 

experience increased persistence and degradation times compared to those expected in the upland area. Soil and 

water properties in wetlands or riparian areas differ from upland areas and thus the capacity to adsorb, transport, 

and transform herbicides may be affected. Soil temperatures, amount of organic matter and degree of saturation 

may change duration and storage of herbicides. Soil pH and level of oxygen present in a soil may increase 

or decrease degradation of herbicides. Generally, anaerobic degradation processes are much slower than the 

degradation processes in well-drained soils where oxygen is present (Table 4-20).

Herbicides Used for Both Aquatic and Terrestrial 

Vegetation Control

Six herbicides are registered for aquatic use by the EPA 

and approved for such use by the BLM nationally: 2,4-

D (salt forms, not esters), diquat, fluridone, glyphosate, 

imazapyr, and triclopyr. Cautions for each herbicide 

vary in the aquatic environment.

2,4-D: The principle hazard is unintended spraying 

or drift to non-target plants; spot treatments applied 

according to the labeled rate do not substantially 

affect native aquatic vegetation or significantly change 

species’ diversity (USDA 2005a, WA Dept of Ecology 

c). Kuhlmann et al. (1995) found no biodegradation of 

2,4-D under anaerobic (sulfate reducing) conditions in 

a laboratory experiment of sediments and groundwater. 

In aerobic riparian soils that have a high content of 

organic material, an active microbial community, high 

pH values, and high temperatures, toxic effects are 

limited because of rapid degradation of 2,4-D. 2,4-D 

may inhibit shoot and/or root growth of macrophytes in 

aquatic systems (Roshon et al. 1999).

Diquat is used in ponds, lakes, canals, and reservoirs where no non-target species are present. It is a non-specific 

herbicide that kills plants on contact but does not kill roots, so it is used for single season control of submerged 

aquatic plants. It is persistent in the environment (up to 3 years) but is quickly adsorbed to soils and sediments, 

immobilizing it and rendering it unlikely to contaminate leachate or runoff. It is not used to treat large areas at 

one time, because decomposition of treated plants may deoxygenate water, potentially resulting in negative effects 

to aquatic fauna.

Table 4-20. Herbicide Half-Life in Anaerobic Soils

Herbicide Half life in Anaerobic Soil 

(days)

2,4-D 333

Bromacil 144-198

Chlorsulfuron 109-263

Clopyralid >1000

Dicamba Not Determined

Diflufenzopyr 20

Diquat >1,000

Diuron 5-100

Fluridone 4-270

Glyphosate 12-70

Hexazinone 30-180

Imazapic >1000

Imazapyr >500

Metsulfuron methyl 338

Picloram >500

Sulfometuron methyl 60

Tebuthiuron Not Determined

Triclopyr TEA <1

Final Environmental Impact Statement, Chapter 4: Wetlands and Riparian Areas
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 212

Fluridone is a non-selective, slow-acting herbicide used in low concentrations to control submerged and 

emergent vegetation in ponds or reservoirs, lakes and canals where long-term contact with the target plants can be 

maintained to achieve control (not flowing waters). It photo-degrades, volatilizes slowly from water, and adsorbs 

to suspended solids and sediments.

Glyphosate would be used along shorelines and banks to control grasses, herbaceous plants and some broadleaf 

trees and shrubs, and is approved for emergent aquatic vegetation in wetlands and estuaries. It may move into 

surface water with eroded soil particles (although it is unlikely it will dislodge from the particles and become 

active) where it rapidly dissipates from surface water by biodegradation and adsorption. Freshwater aquatic 

macrophytes and algae are reported to be susceptible to low amounts (20 mg/l concentrations).

Imazapyr is approved for wetlands, riparian areas, brackish (salty) and coastal waters. Used on saltcedar, 

cordgrass, reed canarygrass, phragmites, and waterlily, it may also remove non-target vegetation. Residual soil 

contamination with imazapyr could be prolonged in some areas, possibly resulting in substantial inhibition of 

plant growth (SERA 2004d). Imazapyr is not likely to degrade in anaerobic soils or sediments, and has been 

shown to strongly bind to peat (American Cyanamid 1986, SERA 2004d).

Triclopyr generally controls woody species in an upland environment but can be used in wetlands and riparian 

areas that go dry for part of the year. It can also be used for spot treatment of Eurasian watermilfoil at low 

application rates, and purple loosestrife in riparian areas, as it does not damage native grasses and sedges. Only 

the TEA (acid) form is approved for selective control of submersed aquatic vegetation. Triclopyr BEE (ester 

form) is hazardous to aquatic life forms in maximum concentrations or spill situations where runoff to open water 

may occur.

Herbicides Used For Terrestrial Vegetation Control

Other herbicides may be used on or near intermittent streams during the dry season, or would be used to control 

vegetation outside of riparian areas using buffer widths applicable to the herbicide being used. However, 

non-target wetland and riparian areas could be exposed to herbicides through a variety of routes, including 

accidental spills or direct spray, local spray drift from adjacent target areas, surface water runoff, and soil erosion 

(Karthikeyan et al. 2003). Risks to wetland and riparian non-target species would depend on a number of factors, 

including the amount, selectivity, and persistence of the herbicide used; the application method used; the timing 

of the application; and the plant species present. Risks to wetlands and riparian areas from surface runoff would 

be influenced by precipitation rates, soil types, and proximity to the application area. Some herbicides (e.g., 

sulfometuron methyl) that adsorb readily onto clay soil particles could be carried off site in runoff situations, 

increasing their risk of affecting vegetation in wetlands and riparian areas.

Unintentional applications can have severe negative impacts on wetland and riparian systems. In particular, 

accidental spills near wetland and riparian areas could be particularly damaging to wetland and riparian 

vegetation. Spray drift can also degrade water quality in wetland and riparian areas and could damage 

non-target vegetation.

Bromacil is not selective, and accidental exposure could injure riparian shade trees and other non-target wetland 

and riparian vegetation. Bromacil is mobile and has the ability to persist in wetland environments.

Chlorsulfuron is effective at low concentrations and is prone to leaching. Hydrolysis rates are the fastest in acidic 

waters and are slower as the pH rises (Sarmah and Sabadie 2002). When hydrolysis rates drop, biodegradation 

becomes the primary loss mechanism. Strek (1998a, b) studied the dissipation of chlorsulfuron in an anaerobic 
213

sediment/water system; biodegradation progressed much more slowly than in aerobic soil systems, with a half-life 

greater than 365 days.

Clopyralid is relatively non-toxic to aquatic plants. Overall, effects to non-target wetland and riparian vegetation 

from normal application of clopyralid are likely to be limited to susceptible plant species in or very near the 

treatment area, and could be avoided by maintaining an adequate buffer between the treatment area and wetland 

and riparian areas (SERA 2004b). Clopyralid is not likely to affect aquatic plants via off-site drift or surface 

runoff pathways unless spilled.

Dicamba direct spray and drift scenarios pose a moderate to high risk to susceptible terrestrial plants. Susceptible 

aquatic algae are at high risk from an accidental spill scenario and from direct exposure at maximum rates. 

Tolerant algae are at low risk from accidental spill at maximum rate. In water, biodegradation is the major 

mechanism for dicamba degradation. Dicamba is mobile in soils and is therefore likely to reach surface water and 

groundwater. The rates of dicamba degradation were generally more rapid in the surface than in the subsurface 

soil microcosms. The study indicated that some riparian wetland soils possess limited potential to degrade 

dicamba (Pavel et al. 1999).

Diflufenzopyr is not approved for the treatment of aquatic plants, but poses a low risk to riparian species and 

aquatic plants via off-site drift.

Diuron: Under the Risk Assessment’s accidental direct spray and spill scenarios, diuron is a high risk to aquatic plants. 

Off-site drift typically poses low to moderate risk to aquatic plants at the typical and maximum rate respectively (ENSR 

2005f). (Diuron use west of the Cascades is expected to be low and limited to specialized circumstances.)

Hexazinone exposure poses a moderate to high risk for aquatic plants from acute and chronic exposures at both 

the typical and maximum application rates. Aquatic algal species are also susceptible to hexazinone exposure. It 

is also likely that aquatic macrophytes are susceptible, based on the effects of hexazinone on algae and terrestrial 

plants (SERA 1997).

Imazapic risk to aquatic plants from accidental spills of imazapic is moderate to high at the maximum application 

rate and low to moderate at the typical application rate (there is no acute risk to aquatic plants in standing water at 

the typical application rate). Aquatic plants are generally not at risk from off-site drift of imazapic, except when 

applied aerially at the maximum application rate with a buffer of 100 feet or less. Imazapic rapidly degrades 

through photodegradation in aquatic systems (SERA 2004c).

Metsulfuron methyl poses a low risk to aquatic macrophytes from acute exposure at upper exposure limits (SERA

2004e). Metsulfuron methyl is stable to hydrolysis at neutral and alkaline pHs. Larsen and Aamand (2001) 

evaluated biodegradation of metsulfuron methyl (25 μg/L) under anaerobic and aerobic conditions in sandy 

sediments; the herbicide did not biodegrade under any of these conditions.

Picloram toxicity to aquatic plants varies substantially among different species. There is low risk to susceptible 

aquatic macrophytes from acute exposure to picloram at the maximum application rate. Because picloram does 

not bind strongly to soil particles and is not rapidly degraded in the environment, it has a high potential for being 

transported to wetland and riparian areas.

Sulfometuron methyl poses a high risk to aquatic plants from accidental direct spray and spills, and a high 

risk to susceptible and aquatic plants from drift. It poses a low risk to terrestrial plants from drift. Aquatic 

plants in standing water are typically at low to moderate risk for adverse effects from surface runoff scenarios. 

Final Environmental Impact Statement, Chapter 4: Wetlands and Riparian Areas
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Sulfometuron methyl should not be applied during high winds, as drift could cause extensive damage to 

vegetation at a substantial distance from the application site.

Tebuthiuron poses a high risk of adverse effects to aquatic plants under Risk Assessment spill scenarios, and 

potentially a high risk for adverse effects from direct spray scenarios. Aquatic plants are not at risk for adverse 

effects under scenarios involving off-site drift of tebuthiuron; however, surface runoff typically poses a risk to 

submerged aquatic plants for herbicide treatments at the maximum application rate, and at the typical application 

rate in sandy soils. Tebuthiuron is resistant to hydrolysis and photolysis in aquatic systems; however, some 

photodegradation has been reported at alkaline conditions (pH=9), and tebuthiuron is expected to biodegrade 

slowly in aquatic systems.

Noxious Weeds and other Invasive Plant Effects

For terrestrial weeds, the various levels of weed control predicted to be achieved by each alternative (Table 4-4 in 

the Noxious Weeds and Other Invasive Plants section in this Chapter) will variously reduce or limit weed-induced 

changes to wetland and riparian vegetation, soil water content, and erosion in wetlands and riparian areas adjacent 

to streams. Removing species like blackberry, saltcedar, or even western juniper upslope will allow native species 

to recolonize the near stream-bank or uplands. Native wetland and riparian species are adapted to the unique 

relationship of inundation of plants or soil by water for various portions of the year and respond well or survive 

such inundations. Restoration or maintenance of upslope native vegetation in western juniper encroachment areas 

would allow water to return to the groundwater system and contribute to seasonal or perennial flows, helping 

maintain and/or restore riparian areas.

For aquatic weeds, six herbicides are registered for use in aquatic environments, and each is effective on specific 

weeds. Glyphosate may be used along shorelines for species such as purple loosestrife, reed canarygrass, giant 

reed, and cattail, as well as for floating aquatic species such as waterlily. It is also used to control grasses, 

herbaceous plants, and some broadleaf trees and shrubs in riparian areas. Imazapyr is used to treat emergent and 

floating plants as well as saltcedar. It is used on cordgrass, reed canarygrass, and floating plants such as waterlily. 

Triclopyr can be effective as a spot treatment for Eurasian watermilfoil because it is relatively selective for this 

species at low application rates. It can also be used to treat purple loosestrife, as it does not damage native grasses 

and sedges. Fluridone, 2,4-D, and diquat are effective treatments for Eurasian watermilfoil, and diquat also 

controls water-thyme, water hyacinth, and is the only herbicide available for giant salvinia, which is not known to 

be in the State of Oregon at this time.

Effects by Alternative

Reference Analysis – No Herbicide Use

Directed livestock use would be expected to increase 6,000 acres east of the Cascades, when compared to the No 

Action Alternative (Alternative 2), and some portion of this increase could occur within riparian and wetland areas. 

Directed livestock trampling on wet soils could cause soil compaction and a breakdown of soil aggregates, with a 

resultant loss of soil porosity, air and water movement, and increased density that increases resistance to infiltration. 

Increased compaction and disturbance within the wetlands could increase sediment being delivered to the stream or 

water body network. Wheeled or tracked mechanical equipment would cause the same effects as livestock.

Mechanical treatments using chainsaws and weed whackers, and manual pulling, could result in cut or pulled 

plants covering the treatment area and making erosion less likely after treatment, although weeds that produce 

vegetatively or that are approaching seed set are normally bagged and removed.
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There would be no effective control available for about 2/3 of the noxious weeds (Appendix 7: Table A7-1), 

and non-herbicide control treatments are generally difficult to implement in riparian areas. Specific weeds in 

riparian areas such as blackberry, Japanese knotweed, and reed canary grass would continue to spread essentially 

unchecked. The noxious weed spread rate would be expected to increase to 14 percent, increasing the likelihood 

of weeds infesting susceptible riparian habitats.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Of the four herbicides available under this alternative, most riparian and wetland treatments would be done using 

aquatic formulations of 2,4-D or glyphosate. 2,4-D has moderate to high risks of negatively affecting non-target 

vegetation, and up to moderate risks for some scenarios for water quality, fish, and wildlife habitats. Glyphosate 

has moderate risks under several of the same Ecological Risk Assessment exposure scenarios44 (see respective 

resource sections in this Chapter). The rapid decay of these herbicides particularly in wetland soils that have high 

organic matter, high pH, and slow or no water movement during application, limits the impacts to root tips and 

aquatic life forms that are found in this environment (Voth et al. 2006).

Directed livestock trampling on wet soils and its resultant adverse effects on soils and water quality (see 

Reference Analysis) could occur, as some portion of the 2,800 acres estimated for this alternative may be directed 

toward riparian areas, particularly as grazing often must occur before seed set. Manual and mechanical effects 

described under the Reference Analysis would occur, but at slightly lower rates.

Control methods including the four herbicides available under this alternative would effectively control 104 of 

the 120 State listed noxious weeds in Oregon, although the remaining 16 include hydrilla, creeping yellow cress, 

waterweed, saltcedar, watermilfoil, perennial pepperweed, and other riparian pests. Weeds would be expected to 

continue spreading at about 12 percent per year, and infest 1/3 of the BLM lands in Oregon in 15 years. Since 

wetlands and riparian areas provide favorable invasive weed habitat, it is expected they would become similarly 

infested.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

The additional eight or nine herbicides available under this alternative (west and east of the Cascades respectively, 

when compared to the four available under Alternative 2) would permit substitution of lower risk herbicides that 

would be effective at lower rates. 2,4-D and glyphosate projected annual acres would decrease by more than 

half when compared to Alternative 2 (No Action), while the replacement herbicides trigger very few moderate 

risks for fish or wildlife, and only one high (fluridone at maximum rates creates a high risk to Special Status 

aquatic invertebrates in the direct spray to pond scenario; Tables 3-14 and 3-15). Moderate risks are limited 

to fluridone at the maximum application rate for fishponds, and hexazinone at typical and maximum rates for 

several categories of wildlife. Projected use of these two herbicides statewide is 500 acres per year total, with all 

hexazinone use expected to be outside of riparian areas.

Effects of non-herbicide treatments would be about that same as described under Alternative 2 (No Action) with 

the possible exception of the effects of prescribed fire for weed control. The 7,000 additional acres for such 

treatment, all east of the Cascades, would most likely be outside of riparian areas. Burning could release ash and 

other nutrients that could blow or be washed to nearby water, but the amount of material released from burning 

invasive annual grasses would not be expected to noticeably affect riparian area function.

Sixteen of the 120 State listed noxious weeds in Oregon could be effectively controlled with the tools and 

herbicides that would be available under this alternative. Further, the projected reduction of the noxious weed 

44 And high risk to vegetation, and to fish under spill scenarios.

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spread rate to seven percent would reduce the occurrence of new infestations by 40 percent when compared to the 

No Action Alternative (Alternative 2).

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

Potential adverse herbicide effects described under Alternative 3 would also apply to this alternative. The 

additional treatment objectives added by this alternative would increase the use rates for several herbicides when 

compared to Alternative 3. While most pose low risk to riparian and wetland values, glyphosate use along rightsof-way would increase an estimated 1,000 acres on the east side, potentially increasing exposure to riparian areas 

and wetlands where roads and other rights-of-way cross or closely parallel these areas (although SOPs require 

the use of aquatic formulation glyphostate in riparian areas). Glyphosate has up to high risks of negatively 

affecting non-target vegetation (at maximum rates), and some (terrestrial) formulations have up to high risks for 

fish and wildlife in certain scenarios. The addition of diuron statewide, and tebuthiuron and bromacil east of the 

Cascades, could also increase risks to riparian habitats, as all three additional herbicides are known groundwater 

contaminants. Bromacil and diuron pose a moderate risk to non-target plants and to various categories of aquatic 

and terrestrial fish and wildlife from off-site drift.

The decrease in noxious weed spread rate to about one-half of its current rate would benefit riparian areas and 

wetlands by proportionately decreasing the likelihood of future infestations. Statewide, 2.2 million fewer BLM 

acres are expected to be infested with noxious weeds in 15 years when compared with the No Action Alternative 

(Alternative 2), with a proportionate decrease of 22,000 acres within the wetland and riparian areas.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

This Alternative is substantially the same as Alternative 4 (Proposed Action) with respect to riparian and wetlands, 

except for the availability of diquat. Diquat is added to this alternative for giant salvinia and as a substitute for 

fluridone if a site becomes resistant or some other factor prohibits that use. Two hundred acres of treatment are 

projected for analysis purposes. Diquat would only be used in water by BLM (although it is EPA registered 

for some terrestrial uses). It is a known groundwater contaminant and considered a high hazard to fish, aquatic 

invertebrates, and large birds, and a moderate risk to various other wildlife groups and non-target plants (it does 

not usually kill roots).

Fish

Affected Environment

Fish are an important cultural, economic, and recreational resource on public lands in Oregon. Declining 

populations of fish have been a management concern. A number of species or stocks have special management 

status as Federally listed, proposed for listing, or are otherwise designated as Special Status (see Appendix 5). 

The PACFISH (USDA, USDI 1995) and INFISH (USDA 1995b) amendments to resource management plans in 

1995 east of the Cascades, and the Aquatic Conservation Strategy standards and guidelines for Riparian Reserves 

as part of the Northwest Forest Plan (USDA, USDI 1994a) west of the Cascades respond to concerns for the 

continued existence of a number of species.
217

The Magnuson-Stevens Fishery Conservation Act requires the identification of habitat “essential” to conserve and 

enhance Federal fishery resources that are commercially fished. Essential Fish Habitat (EFH) is defined as those 

waters and substrate necessary for spawning, breeding, feeding, or growth to maturity (50 C.F.R. 600.10). EFH 

is located on portions of seven of the nine BLM districts in Oregon. EFH for Chinook and Coho salmon includes 

all streams, lakes, ponds, wetlands tributaries and other water bodies currently viable and most of the habitat 

historically accessible to these fish (Pacific Fishery Management Council 2004).

The BLM in Oregon administers lands directly affecting approximately 4,586 miles of fish-bearing streams 

and over 277,946 acres of reservoirs and natural lakes. Fish habitats range from small isolated desert springs 

in southeast Oregon to large inland and coastal rivers, such as the Columbia, Rogue, and Umpqua and their 

tributaries.

Fish and Their Habitat

The most significant group of native fishes found in Oregon, in terms of their ecological, cultural, and commercial 

importance, is the salmonid family. All members of this group, which includes salmon, trout, char, and whitefish, 

require relatively pristine, cold freshwater habitats during part or all of their life cycles. Therefore, they are 

heavily dependent on the conditions of the surrounding forests and rangelands to ensure their survival (Meehan 

1991).

Salmonid productivity within a freshwater system is dependent on the underlying stream productivity during the 

period of use by salmonids during their life cycle. Five general factors determine the suitability of aquatic habitat 

for salmonids: flow regime, water quality, habitat structure, food (energy) source, and biotic interactions.

All salmonids require suitable habitat for spawning, incubation, and rearing. Generally, adult salmon require 

spawning gravel (less than 2 inches in diameter) and overhead stream bank or vegetative cover from predation. 

Eggs and newly hatched salmon (alevins) require stable gravel, cool (less than 57° F), and highly oxygenated 

water (Meehan 1991). Bull trout, which tend to spend most, if not all of their life in inland waters, require water 

less than 42° F for spawning and rearing of newly hatched young. Salmonids prefer cold water, and temperatures 

above 77° F are lethal to most species in this family (Meehan and Bjornn 1991).

Migrant salmonids pass through several distinct habitats while traveling to and from feeding or breeding habitats, 

utilizing the full extent of the watershed. The importance of each habitat type differs by species. Chinook 

salmon, for example, spawn in the mainstem of a river. Upon emerging from the gravel, individuals either 

start their migration to the sea within their first year (ocean-type) or mature within rivers for 2 to 3 years before 

migrating to sea (stream-type). In contrast, resident trout populations, such as rainbow, bull, and cutthroat trout, 

may spend their life (5 to 6 years) in various freshwater systems, including small streams or lakes, and do not 

migrate to the sea (Meehan and Bjornn 1991).

Various fish species have been introduced into aquatic systems throughout Oregon. Most of the non-native 

species have been introduced to promote sport-fishing opportunities. Some were introduced illegally. 

Introduced salmonids (such as brook, brown, lake, and hatchery-raised rainbow trout), centrarchids (such as 

bass and sunfish), and percids (such as walleye) now support many, if not most, of the non-native sport fishing 

opportunities within these regions (Mills 1994).

Final Environmental Impact Statement, Chapter 4: Fish
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Setting - Aquatic Systems

Due to the topographical, geological, vegetative, and climatic variation across the analysis area, considerable 

variation in aquatic systems exists. Five general settings for aquatic systems present on BLM lands within 

Oregon are discussed below.

The aquatic community consists of macrophytes (large aquatic plants) and phytoplankton (free-floating algae), 

macroinvertebrates (aquatic insects and clams), fish, birds, and mammals (such as muskrats and otters). All of 

these organisms are interrelated in the aquatic community through the food chain. Organisms that play a role 

in the aquatic community require a certain set of physical and chemical conditions to exist, such as nutrient 

requirements, oxygen, light, and space.

Aquatic food chains are dependent on primary production as a source of energy within the ecosystem. For aquatic 

systems, primary production can occur in the water or out of the water in riparian areas. Numerous invertebrate 

species feed directly on primary producers through feeding functions such as grazing, scraping, shredding, and 

collecting. Other invertebrate and fish species feed on these invertebrates, which then become food for fish or 

other predators.

Great Basin

A portion of the western Great Basin is found in south-central Oregon and covers most of Lake and Harney 

counties. Streams in this area never reach the ocean, but are instead confined, typically resulting in terminal lakes, 

marshes, or sinks that are saline. The fish in this area are adapted to extreme conditions, and many have limited 

or very limited ranges. Trout are found in both lakes and streams at all elevations within the basin in Oregon 

(ODFW 2005), with chubs and suckers found in isolated lower reaches. Several of these are Federally Listed (see 

Appendix 5).

The most significant problem facing the low elevation (desert) fish is the limited water supply. Many desert fishes 

have a tenuous hold on survival under natural conditions, occurring only in the few permanent springs, rivers, and 

lakes, and their existence has been placed in doubt by human activities (Deacon and Williams 1991).

Coast Range River Systems

Coast range river systems are relatively short systems, with a high drainage density and flowing directly into the 

Pacific Ocean. Annual precipitation levels are high, with frequent high water events occurring throughout fall, 

winter, and spring seasons. Summer flows are provided by subsurface storage and thunderstorm events. Native 

fish species typically present include sculpin, coastal cutthroat trout, Coho salmon, Chinook salmon, chum 

salmon, rainbow trout, steelhead, southern green sturgeon, lamprey, and a few minnow and sucker species. As 

in all stream systems throughout the region, complex life history assemblages are often present for salmonid 

and lamprey species, including resident, fluvial, and anadromous life history strategies. Juvenile anadromous 

salmonids rear in fresh water for a few months to more than two years, depending on species and adult migration 

timing. Non-native species sometimes present include striped bass, smallmouth bass, and American shad. 

Coastal aquatic food chains are generally more detritus based45 than inland systems.

45 Small streams are often shaded from direct sunlight, inhibiting primary production from algae or macrophytes. 

Bacteria and fungus decompose the leaves and wood entering the stream from the forest, and in turn are eaten by 

shredder organisms. The smaller particles (detritus) shredded by the insects, and also their feces, in turn become food 

for other organisms downstream.
219

Several fish stocks in this area are Federally Listed (Appendix 5). Factors negatively affecting fish habitat include 

forest management, agriculture and livestock management, dams and barriers, urban and industrial development, 

mining, and estuary degradation.

Cascade Mountain River Systems

Cascade Mountain river systems are generally longer than coast range systems, with a moderate to high drainage 

density, and may drain directly into the Pacific Ocean or to the Willamette or Columbia Rivers. Rivers found in 

this region include in part the Klamath, upper Rogue, upper Umpqua, McKenzie, Sandy, and upper Deschutes. 

Annual precipitation levels are moderately high, but vary considerably, depending on elevation and season. 

Summer flows are provided by snowmelt, subsurface storage, and thunderstorm events. At higher elevations, 

above migration barriers, native fish species typically present include coastal cutthroat trout, rainbow trout, 

sculpin, and dace. Bull trout46 are also present in some locations. Below migration barriers, Coho salmon, 

Chinook salmon, and steelhead are generally present, and some minnow and sucker species are occasionally 

present. Other less common native fish species are also present. Non-native fish species often include brook 

trout and, occasionally, brown trout. Food chains are more detritus based at higher elevations, with increasing 

contributions from primary production47 within the stream occurring at lower elevations.

Several fish species or stocks in this area are listed as threatened (Appendix 5). Contributing factors are similar 

to factors negatively affecting fish habitat within the Coast Range River System but also include hybridization, 

ocean conditions, potential overfishing, and other factors.

Eastside Rangeland Stream Systems

Stream systems occurring on rangelands east of the Cascade Mountains are long and widely spaced. The vast 

majority drain into the Columbia River, and a few drain into the Snake River and Great Basin. Major rivers in 

this area include the lower Deschutes, lower John Day, and Owyhee. The climate is generally arid, and annual 

runoff patterns tend to be dominated by annual spring snowmelt. Many headwater channels are located in isolated 

mountain ranges. Summer flows are provided by snowmelt, subsurface storage, and thunderstorm events. Native 

fish species are generally rainbow trout, steelhead, Chinook salmon, bull trout, and several minnow and sucker 

species. Catfish and other less common native fish species are also present. Non-native fish species often include 

smallmouth bass and sunfish. Primary production is important to the food chain in these stream systems.

As with other stream systems in the State, several species/stocks are Federally Listed (see Appendix 5). Threats 

include hydropower development, water withdrawals, irrigation diversions, siltation, and pollution, commercial 

and sport harvest, predators and altered predator dynamics, degraded riparian and instream habitat, water 

temperature, influences of hatchery fish, and non-point source pollution.

Eastside Mountain Stream Systems

Eastside mountain streams occur in mountain ranges east of the Cascade Mountains and include the upper 

Deschutes, John Day, and Walla Walla rivers. They are generally either the headwaters of eastside rangeland 

stream systems, or flow directly into the Columbia River system. Most precipitation occurs during the winter 

months as snow, and annual runoff generally follows a classic snowmelt pattern. Native fish species are generally 

46 Bull trout, Salvelinus confluentus, is a char of the family Salmonidae and native to northwestern North America. It was 

historically part of the “Dolly Varden” (S. malma), but was re-classified as a separate species in 1980.

47 Primary productivity is the process by which organisms (autotrophs) make their own food from inorganic sources using 

solar energy to carry out metabolic processes and build cellular material.

Final Environmental Impact Statement, Chapter 4: Fish
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rainbow trout and steelhead, but Chinook salmon, bull trout, and a few minnow and sucker species may also be 

present. Many Federally Listed and other Special Status fish species found in this region (see Appendix 5) are 

also found in the Rangeland Stream Systems and are partially dependent on conditions in both areas. Food chains 

are similar to those found in the Cascade Mountains, but may have a higher primary productivity component.

Environmental Consequences

Effects to fish can come from the vegetation treatments proposed under the alternatives, and from the differences 

in future levels of invasive plants predicted for those alternatives. Although the fish species considered in this 

document have a variety of different habitat requirements and different abilities to tolerate changes to those 

habitats, there are some broad effects that treatments would be likely to have on all aquatic habitats and species. 

In general, any activity with the potential to alter aquatic habitats or water quality would also have the potential to 

affect fish found in those habitats.

Invasive plants or vegetation treatments may affect habitat important to one or more specific fish life history 

requirements. For instance, the spawning, rearing, and feeding requirements of a particular fish species may be 

different and specific within that species’ habitat. Therefore, effects must consider multiple life stages and thus 

the multiple habitat needs of a particular species.

All else being equal, the potential to adversely affect fish species that are narrowly endemic would be greater 

than the potential to affect species that are broader ranging. Standard Operating Procedures require vegetation 

treatments to be fine-tuned at the site-specific level to ensure that these narrow endemics are not negatively 

affected.

In general, the alternatives proposed in this analysis would be expected to have short-term negative and long-term 

beneficial effects on aquatic habitats. With the Standard Operating Procedures and PEIS Mitigation Measures, it 

is anticipated that negative effects would be minimized. Most herbicide uses proposed by the alternatives, those 

reducing the effects of invasive plants or improving habitat, would have long-term beneficial effects on fish and 

their habitats.

Effects Common to All Alternatives

The intensity and extent of treatment effects to fish and their habitat will vary, depending on several factors 

including the amount of area treated; soil type, proximity of the treatment to water, hydrologic regime and 

weather conditions during and after treatment; temperature, channel morphology and large woody debris; and 

biota present in surface water.

Herbicide Effects

The potential for effects on fish because of herbicide treatments would vary by the extent and method of treatment 

and herbicide used. Herbicides could enter water bodies and come into contact with fish or elements of the food 

chain on which they depend through drift, runoff, leaching, wind transport, accidental spills, and direct spraying. 

Potential impacts include mortality, reduced productivity, abnormal growth, and alteration of critical habitat. In 

general, risk to fish from spray drift is greater with narrower buffer zones, greater application rates, and greater 

application heights (i.e., aerial application or ground application with a high boom). Risk to fish from surface 

runoff is influenced by precipitation rate, soil type, groundwater depth, and application area. There would be 

a risk to fish associated with most accidental exposure scenarios (i.e., direct spray or spill into a water body). 
221

Persistent herbicides (e.g., picloram) adsorbed to soil particles could also be carried off-site by water, affecting 

fish in nearby aquatic areas.48 Application rate was a major factor in determining risk, with higher application 

rates more likely to pose a risk to fish under the various exposure scenarios.

Herbicides may be toxic to aquatic plants and invertebrates, thus indirectly affecting fish by reducing primary 

production or the trophic structure of invertebrate communities. Low concentrations of herbicides can affect 

benthic49 algae communities (McCain et al. 2000). The variation in toxicity to aquatic organisms between 

different formulations for the same herbicide can be substantial (SERA 2003a). In addition, timing of application 

can result in different effects. For example, a springtime application of glyphosate at recommended rates in a 

lake ecosystem, where dissolved oxygen levels are low or water temperatures are elevated, could be hazardous to 

young fish because decaying plants could lower dissolved oxygen levels (Folmar et al. 1979).

All of the herbicides pose some risk to non-target terrestrial and aquatic plants, and damage to riparian and 

aquatic plants may affect fish. The Native and Other Non-Invasive Vegetation and Wetland and Riparian Areas

sections in this Chapter discuss these risks, as well as herbicide application practices that can be used to reduce 

risk. Species that depend on non-target plant species for habitat, cover, and/or food may be indirectly impacted 

by a possible reduction in terrestrial or aquatic vegetation. For example, accidental direct spray, off-site drift, and 

surface runoff may negatively affect terrestrial and aquatic plants, reducing the cover and food available to fish 

within the stream.

Endocrine disrupters: The EPA reports effects of endocrine disruption in animals can “include abnormal thyroid 

function and development in fish and birds; decreased fertility in shellfish, fish, birds, and mammals; decreased 

hatching success in fish, birds, and reptiles; demasculinization and feminization of fish, birds, reptiles, and 

mammals; defeminization and masculinization of gastropods, fish, and birds; decreased offspring survival; and 

alteration of immune and behavioral function in birds and mammals.” There are some data indicating 2,4-D may 

be endocrine disrupting (EPA 2005a, SERA 2006), and this evidence is being pursued further. There are also 

studies showing developmental and thyroid effects, possibly from endocrine disruption, for sulfometuron methyl 

(SERA 2004f). Triclopyr and glyphosate have been evaluated for endocrine disrupting effects, and the weight of 

evidence indicates that these herbicides cause no specific toxic effects on endocrine function (SERA 2002). 2,4-D 

and glyphosate are included in the EPA’s first list of chemicals to be screened for endocrine disruption, although 

inclusion on that list is based only on exposure and does not indicate any evidence of risk (see Non-BLM Actions 

Potentially Affecting the Use of Herbicides on BLM Lands in Oregon section in Chapter 1). 

Exposure Scenarios

Water Contamination from Drift: Herbicide drift is one of the mechanisms of herbicide movement when applied 

as a spray. Drift or off-target movement can result in unintended injury to non-target plant species, contamination 

of surface waters, and contamination of ecologically susceptible areas. Drift occurs when fine droplets of liquid 

herbicide become windborne and are transported to adjacent areas. It is a physical process that depends on droplet 

size, weather, and topography rather than specific properties of an herbicide. The herbicide droplets can be 

subsequently deposited on surface waters that either contain aquatic species or serve as runoff conduits to water 

containing aquatic species. Risk Assessments predicted off-site drift and resulting water body (pond and stream) 

concentrations using the computer model AgDrift.

48 Ecological Risk Assessments predicted no or low (diuron) risk to fish because of wind transport of herbicides on soil 

particles under all evaluated scenarios.

49 Benthic: Of or relating to or happening on the bottom under a body of water.

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Drift studies typically focus on broadcast treatments using boom or aerial application. Drift associated with 

backpack (directed foliar applications) is likely to be comparatively low although studies quantitatively assessing 

drift after backpack applications were not found. Application pressure, nozzle size, nozzle type, spray angle, 

and spray volume are all factors in determining droplet size. The risk of off-site effects from spray applications 

(aerial, boom, and backpack) would most likely be related to drift. PEIS Mitigation Measures and Standard 

Operating Procedures applicable under all alternatives would reduce the risk of surface water contamination from 

spray drift. For example, one Standard Operating Procedure requires the use of spray equipment delivering 200- 

to 800-micron diameter droplets. A 200 micron droplet would be expected to drift about 30 feet if dropped from 

an altitude of 10 feet in a 3 mile-per-hour wind (see Water Resources section, Table 4-18).

In certain situations, contamination of susceptible areas, wetlands, and open waters may occur during aerial 

spraying. Two herbicides included in Alternatives 3, 4, and 5 (chlorsulfuron and metsulfuron methyl) are 

of particular concern in drift situations because of the higher potential for impacts to non-target vegetation, 

which can affect fish habitat and food. The risk of direct mortality from these two herbicides is low. However, 

Alternatives 3 and 4 would not permit aerial application of any herbicide west of the Cascades, and chlorsulfuron 

and metsulfuron methyl aerial applications are limited by PEIS Mitigation Measures to areas with difficult 

access, where no other means of application is possible. Alternative 2 (No Action) does not allow the use of 

chlorsulfuron, metsulfuron methyl, and sulfometuron methyl.

Water Contamination from Runoff, Leaching, and Percolation: All herbicides can potentially enter streams and 

other water bodies through water transported by runoff, leaching, or percolation. Rain events could transport 

herbicides to waterways, and convey them to aquatic species’ habitat. Soil type and herbicide stability, 

solubility, and toxicity can determine the extent to which an herbicide will migrate and affect surface waters and 

groundwater. For example, picloram is highly soluble and readily leaches through sandy soil. It is also resistant 

to biotic and abiotic degradation processes, and can move from target plants, through roots, down into the soil, 

and into nearby non-target plants. Although relatively non-toxic to humans and other terrestrial species, picloram 

is moderately to slightly toxic to juvenile or early developing fish.50 Standard Operating Procedures and PEIS 

Mitigation Measures (Appendix 2) would help protect riparian vegetation when using picloram by requiring 

appropriate treatment buffers. Glyphosate and 2,4-D, though very soluble, bind well with organic matter in soils. 

Glyphosate is not easily leached; 2,4-D leaching potential is considered moderate. All of the herbicides proposed 

for use under all of the alternatives are susceptible to transport in surface runoff, especially if applications 

are followed immediately by high rainfall events. However, Standard Operating Procedures preclude most 

applications if rain is imminent.

Exposure to herbicides is plausible for fish under each alternative. Alternative 5 poses the highest likelihood of 

exposing fish to herbicides, and Alternative 2 (No Action) has the lowest likelihood of exposure. Actual effects 

will vary depending on the herbicides used, site-specific conditions, and the design of the project. Appropriate 

project design and application of Standard Operating Procedures will minimize or avoid exposure of fish to 

herbicides under all alternatives.

Water Contamination from Accidental Spills: The most common reason for fish-kills due to herbicide application 

is from the accidental entry of the herbicide into a stream or pond or the indirect effect of lowered dissolved 

oxygen (DO) in the water resulting from plant kill and resultant decay. Fish populations can withstand the 

everyday fluctuations of DO but many types of fish cannot tolerate prolonged periods of low DO. When large 

amounts of aquatic plants are killed by an herbicide application the decaying vegetation and lack of oxygen 

production may cause DO to become so low that fish cannot survive in the water and a fish-kill occurs. If an 

50 Stehr et al. (2009) reported juvenile rainbow trout had a picloram related 96-hour LC50 of 41 ppm and juvenile bull 

trout 24 ppm. 
223

herbicide that is effective on higher plants and not phytoplankton is used, the potential for a fish-kill can be 

minimized because phytoplankton will continue to produce oxygen. The likelihood of fish-kills is less in cooler 

water because it can hold more oxygen than warm water.

The risk to fish from spill scenarios in a small pond or small stream are addressed in the Ecological Risk 

Assessments and displayed on the risk tables. Adverse effects to fish decrease with distance downstream or away 

from the spill site because of mixing.

The Potential for Synergistic Toxicity of Different Pesticides in the Aquatic Environment

Pesticide mixtures are common in the aquatic environment, including lakes, rivers, streams, and other surface 

waters that support aquatic life (Gilliom 2007). The cumulative toxicological impacts of pesticide mixtures are of 

particular concern for salmon and steelhead populations that are currently Federally Listed. 

Extensive surface water monitoring for pesticides, as part of the U.S. Geological Survey (USGS) National 

Water Quality Assessment program (NAWQA), has shown that current-use pesticides are frequently detected in 

salmon-supporting river systems (Laetz et al. 2009). Furthermore, pesticides often occur in mixtures with other 

pesticides. Analysis of NAWQA monitoring data found that more than 90 percent of water samples from urban, 

agricultural, and mixed-use streams contained two or more pesticides (Gilliom 2007). The toxicological effects of 

these mixtures on the health of salmon are largely unknown (Laetz et al. 2009).

To define the extent to which insecticides in mixtures interact, Laetz et al. (2009) exposed juvenile Coho 

salmon (Oncorhynchus kisutch) to all possible binary combinations of the insecticides diazinon, malathion, 

and chlorpyrifos and the insecticides carbaryl and carbofuran. Although the authors did not study the effects of 

herbicides on these fish, these results have important implications for Ecological Risk Assessments, particularly 

those that focus on the toxicity of individual chemicals as the basis for estimating impacts to imperiled aquatic 

species. Although the importance of multiple stressors is widely recognized in aquatic ecotoxicology (Eggen et 

al. 2004), pesticide mixtures continue to pose major challenges for natural resource agencies (Gilliom 2007; Lydy 

et al. 2004). Salmon exposed to mixtures containing some of the most intensively used insecticides in the western 

United States showed either concentration-additive or synergistic neurotoxicity as well as unpredicted mortality. 

This implies that single insecticide assessments will systematically underestimate actual risks to Federally Listed 

species in salmon-supporting watersheds where mixtures of pesticides occur. 

Most insecticide treatments on BLM lands in Oregon are likely to be spatially or temporally separated from 

most herbicide treatments proposed in this EIS, so virtually no organisms except, conceivably, plants, would be 

expected to have active doses of both materials at the same time. Cumulative adverse effects to humans or other 

elements of the environment are most likely when two pesticides share a common mechanism of toxicity. That 

is, they both affect an organism the same way. Cumulative effects assessments conducted by the EPA typically 

begin by grouping pesticides by mechanism of toxicity (EPA 2002). Because insecticides and herbicides work 

so differently, even a concurrent application would be unlikely to result in significant synergistic environmental 

effects when both products are applied within label limits. 

Effects of BLM-Evaluated Herbicides

As described under Risk Assessments in Chapter 3 and Appendix 8, BLM or Forest Service Risk Assessments are 

available for the 18 herbicides analyzed in this EIS. For fish, the essential biological requirements (i.e., survival, 

growth, and reproduction) are the attributes to be protected from herbicide exposure. Ecological Risk Assessment 

endpoints, for the most part, reflect direct effects of an herbicide on fish, but indirect effects were also considered. 

The measures of effect associated with the assessment endpoints generally consisted of acute and chronic toxicity 

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data (from herbicide registration documents and from the available scientific literature) for the most appropriate 

surrogate species.51 Resultant benchmarks are referred to as toxicity reference values (TRVs).

Exposure scenarios for risk reporting were selected based on actual BLM herbicide usage under a variety of 

conditions. The exposure scenarios considered are shown on Table 3-14.

A major potential problem associated with herbicide use is off-site drift to non-target resources. Herbicides 

drifting off site may eventually reach water bodies and contaminate fish. The AgDrift computer model was used 

to estimate off-site herbicide transport due to spray drift. The GLEAMS computer model was used to estimate 

off-site transport of herbicides in surface runoff and root zone groundwater transport. The CALPUFF computer 

model was used to predict the transport and deposition of herbicides sorbed (i.e., reversibly or temporarily 

attached) to wind-blown dust. Each model simulation was approached with the intent of estimating the maximum 

herbicide exposure concentration that could result from the given exposure scenario.

Bromacil is a non-selective, broad-spectrum, systemic herbicide that can be persistent in aquatic systems. It is 

not registered for use in riparian and aquatic systems. Bromacil does not tend to bioconcentrate appreciably in 

fish tissue. Bromacil poses a low to moderate risk to fish in streams and ponds under typical and accidental direct 

spray and spill scenarios.

Off-site drift of bromacil generally does not pose a risk to fish in streams or ponds (Table 3-14). Surface runoff 

poses no risks to fish in streams, but could pose a low acute and chronic risk to fish in ponds (there is a low 

chronic risk associated with the typical application rate, in watersheds with sand or loam soils and 10 to 50 inches 

per year of precipitation). Because bromacil has a higher affinity for water than organic carbon, it is likely to run 

off from soils into water bodies. Because of the non-selective nature of bromacil and its likelihood for runoff, it is 

not normally applied near water bodies, especially ponds.

Chlorsulfuron is a selective, ALS-inhibitor herbicide. It is not registered for use in aquatic systems. 

Chlorsulfuron’s physical and chemical properties suggest that it is highly soluble in water, and is likely to remain 

dissolved in water and runoff from soils into water bodies. In addition, this herbicide has a long half-life in 

ponds, but is not likely to bioconcentrate in aquatic wildlife. However, none of the evaluated scenarios, including 

accidental direct spray and spill of chlorsulfuron, pose any risk to fish in streams and ponds.

Diflufenzopyr is a selective, systematic post-emergence herbicide active ingredient. It is not registered for use in 

aquatic environments. The physical and chemical properties of diflufenzopyr suggest that this herbicide would 

be removed from an aquatic environment relatively rapidly following contamination and would not appreciably 

bioconcentrate in fish tissue. The Ecological Risk Assessment shows that diflufenzopyr does not pose a risk to 

fish under any of the Ecological Risk Assessment scenarios.

Diquat is a non-selective, contact herbicide the BLM would use only to control aquatic plants.52 Plant species 

controlled using diquat include Eurasian watermilfoil, water-thyme, water hyacinth, and giant salvinia.

One study reported the likelihood of bioconcentration in aquatic species, but other studies suggest that diquat’s 

bioconcentration potential is minimal (Howard 1991, Petit et al. 1995, MacKay et al. 1997). An accidental spill 

of diquat would pose a high risk to fish. Direct spray of diquat to ponds, as would occur with typical aquatic 

applications, would pose a low risk to fish (Table 3-14). Direct spray to streams, which are not typical application 

sites, would pose a low risk to fish. Because diquat is an aquatic herbicide, risk to aquatic organisms via off-site 

drift and surface runoff scenarios was not evaluated.

51 e.g., bluegill sunfish for warm water species and rainbow trout for coldwater species.

52 Diquat is also registered for certain terrestrial uses, but BLM does not propose non-aquatic use.
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Given the short-term risks of diquat to fish, this herbicide is used on a restricted basis, and then only in ponds 

that support very few native aquatic species because they are dominated by invasive plants or contain species not 

effectively controlled with other herbicides. Other aquatic herbicides evaluated in this EIS (fluridone, 2,4-D, and 

imazapyr) also pose relatively low risk to fish and would be used instead of diquat when native aquatic species are 

present, as appropriate.

Diuron is a broad-spectrum herbicide with a relatively short half-life and little to no impact on measured water 

quality variables (Perschbaucher et al. 2004). It would not be used in riparian or aquatic habitats. Previous 

studies suggest that diuron tends to remain in the soil rather than moving into groundwater or running off into 

water bodies (Mueller-Warrant and Griffith 2005).

Diuron has a low to moderate tendency to bioaccumulate in aquatic organisms (National Library of Medicine 

2002). Call et al. (1987) found the bioaccumulation in fathead minnows (Pimephales promelas) to be between 

144 and 157 times the concentration in the surrounding water, with 76 percent eliminated within 24 hours after 

return to clean water. These results suggest that diuron has a low tendency to bioaccumulate in these fish. 

Accidental direct spray and spill scenarios pose a moderate to high risk to fish (Table 3-14). When applied at 

the typical or maximum application rate, off-site drift of diuron poses no to low risk to fish. At the maximum 

application rate, off-site drift of diuron poses low risk to fish in streams and ponds under most application 

scenarios with a buffer distance of 100 feet or less. According to the Ecological Risk Assessment, surface runoff 

poses low risk to fish in ponds in the majority of scenarios. Surface runoff also poses a low risk to fish in streams 

in watersheds with at least 25 inches of rain per year (mostly at the maximum application rate). In all cases, 

effects would be less likely in watersheds with loam soils.

Fluridone is a slow-acting, broad-spectrum aquatic herbicide that can be used selectively for management of 

aquatic species, including water-thyme and Eurasian watermilfoil. As fluridone is relatively non-persistent, it is 

not expected to affect water quality for a substantial period of time (Muir et al. 1980).

Fluridone has little tendency to bioaccumulate in fish (Washington Department of Health 2000). An accidental 

spill of fluridone poses moderate risk to fish. Direct spray of fluridone over a pond at the maximum application 

rate poses a low risk to fish. Accidental direct spray of fluridone over a stream (aquatic herbicides are not 

typically applied to streams) at the maximum application rate poses no or low risk to fish. Because fluridone is an 

aquatic herbicide, off-site drift and surface runoff scenarios were not evaluated.

Imazapic, an ALS-inhibitor, is a selective, systemic herbicide. It would not be used for treatment of aquatic 

vegetation, but could be used in riparian areas. Leafy spurge and the perennial mustards would be target species.

The average half-life for imazapic in a pond is 30 days, and this herbicide has little tendency to bioaccumulate in 

fish (Barker et al. 1998). According to the manufacturer’s label, imazapic has a high runoff potential from soils 

for several months or more after application. Accidental direct spray and spill scenarios generally pose no risk to 

fish when imazapic is applied at either the typical or maximum application rate. Risk Assessments show fish are 

not at risk from off-site drift or surface runoff of imazapic.

Diflufenzopyr + dicamba is a selective, systematic herbicide, with low residence times in water bodies and a low 

bioconcentration potential (National Library of Medicine 2002). Diflufenzopyr + dicamba application does not 

pose a risk to fish under any application scenario (also see toxicity studies under dicamba and diflufenzopyr).

Sulfometuron methyl, an ALS-inhibitor, is a broad-spectrum, pre- and post-emergent herbicide. It is not approved 

for use in aquatic systems, but could be used to treat perennial pepperweed, hoary cress, and other weeds 

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associated with riparian systems if the application was made far enough from water to ensure that the active 

ingredient did not get into the water. Sulfometuron methyl has a relatively low residence time in aquatic systems, 

and bioaccumulation in aquatic organisms has not been detected (Extoxnet 1996c). According to Ecological Risk 

Assessments, there would be no risks to fish associated with the use of sulfometuron methyl under any of the 

evaluated scenarios.

Tebuthiuron is a relatively non-selective herbicide absorbed by plant roots through the soil. Tebuthiuron has little 

tendency to bioaccumulate in aquatic organisms (National Library of Medicine 2002), but may have a moderate 

residence time in water bodies (over 1 year in anaerobic conditions).

Under an accidental spill scenario, tebuthiuron would pose a low risk to fish in ponds. Fish are not at risk from 

accidental direct spray, off-site drift, and surface runoff.

Effects of Forest Service-Evaluated Herbicides

2,4-D has formulations that are registered for use on aquatic vegetation, including water hyacinth and Eurasian 

watermilfoil, and as a tank mix partner to control purple loosestrife. The toxicity of 2,4-D to fish is relatively 

low (Norris et al. 1991). Risk is greater under scenarios of direct application to water bodies or accidental direct 

spills. The ester forms of 2,4-D (including the BEEs found in Aqua-Kleen) are approximately 200 to 1,000 times 

more toxic to fish than the amine forms, when toxicity is measured by acute (24- to 48-hour) LC-50 values. 

While these esters are chemically stable, they are short-lived in natural water because of biological degradation. 

At the typical application rate, 2,4-D poses a low risk to fish, while at the maximum application rate, 2,4-D poses 

a moderate risk to fish under scenarios of accidental direct spray or spill to a stream and pond. Routine (non-spill) 

acute and chronic exposure scenarios do not pose a risk to fish.

Clopyralid is a selective herbicide most effectively used post-emergence for the control of broadleaf weeds. It 

is not registered for aquatic vegetation treatment, but can be used in riparian areas if the application does not 

affect standing water. Clopyralid is used to treat teasel, common cocklebur, and several species of thistles and 

knapweeds that could be found in riparian areas. Based on limited acute bioassays, clopyralid appears to be 

relatively non-toxic to fish. The Risk Assessment only predicted risks to aquatic organisms associated with 

accidental spill scenarios, with low risk to fish for the typical and maximum application rates.

Dicamba is not registered for use in aquatic environments. The Ecological Risk Assessment shows a low risk to 

susceptible fish under the spill scenario at the maximum rate, and no risk to fish under other exposure scenarios. 

Off-site drift and surface runoff of dicamba also present no risk to fish.

Glyphosate is a non-selective systemic aquatic herbicide. It can be applied as a broadcast, spot, stem injection, 

or wipe application, and is effective in controlling purple loosestrife, cattail, and in some situations, saltcedar. In 

general, glyphosate is immobile in soil, being readily adsorbed by soil particles and subject to microbial degradation 

(Norris et al. 1991). This immobility reduces the potential for glyphosate to enter water bodies during runoff.

Based on bioassays, technical grade glyphosate is classified as non-toxic to practically non-toxic in freshwater 

fishes (EPA 1993). Some formulations are more toxic to fish than technical grade glyphosate. At the typical 

application rate, the less toxic formulation of glyphosate poses little risk to fish, except under accidental spill 

scenarios, for which there is a low to moderate risk to fish. At the typical application rate, the more toxic (nonaquatic) formulation of glyphosate poses a high risk to fish under accidental spill scenarios, and a low risk under 

routine acute exposure scenarios (moderate risk to susceptible fish species). At the maximum application rate, 

the less toxic formulation of glyphosate poses a low risk to fish under acute exposure scenarios. Accidental spills 
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for the maximum application rate pose moderate to high risk to fish. At this same application rate, the more toxic 

formulation of glyphosate poses a high risk to fish under accidental spill scenarios, and moderate risk to fish under 

acute exposure scenarios. Based on these data, the EPA classified glyphosate formulation as moderately toxic to 

practically non-toxic to freshwater fishes (SERA 2003a).

Hexazinone: According to Ecological Risk Assessments, there is no risk to fish in ponds or streams associated 

with any exposure scenario for hexazinone (accidental spill scenarios were not modeled).

Bioassays on the active ingredient hexazinone and commercial formulations that include hexazinone indicate that 

commercial formulations are substantially less toxic than the active ingredient alone, even when exposures are 

normalized for hexazinone levels (Wan et al. 1988).

Imazapyr is an ALS-inhibiting herbicide used in the control of a variety of grasses, broadleaf weeds, vines, brush 

species, and aquatic vegetation. It is effective in the control of saltcedar, which dominates many riparian systems 

in the West. Imazapyr is relatively non-toxic to fish (SERA 2004d). At the typical and maximum application 

rates, imazapyr poses no risk to fish in streams or ponds under acute and chronic exposure scenarios. For the 

typical application rate, moderate risk is predicted for susceptible fish species for accidental spill scenarios. For 

the maximum application rate, high risk to susceptible fish and low risk to tolerant fish are predicted for accidental 

spill scenarios.

Metsulfuron methyl is a selective ALS-inhibiting herbicide used pre- and post-emergence in the control of many 

annual and perennial weeds and woody plants. It is not registered for use in aquatic situations, but can be applied 

in riparian areas if the herbicide does not come into contact with water (SERA 2004e). Overall, metsulfuron 

methyl appears to have a very low potential to cause any adverse effects in aquatic animals. According to the 

Ecological Risk Assessments, metsulfuron methyl poses almost no risk to fish in streams and ponds under 

accidental, acute, and chronic exposure scenarios involving application of typical and maximum rates (although 

an accidental spill at the maximum application rate poses a low risk to susceptible fish species).

Values from 96-hour LC50 values for acute toxicity in bluegill sunfish and rainbow trout ranged from 

approximately 150 mg/L to 1,000 mg/L for both species (SERA 2004e). In rainbow trout, signs of sub-lethal 

toxicity include erratic swimming behavior, lethargy, and color change at concentrations around 100 mg/L, with 

a no observable effects concentration (NOEC) of 10 mg/L (SERA 2004e). One investigation did not observe any 

effects on rainbow trout hatching, larval survival, or larval growth over a 90-day exposure period, at a NOEC of 

up to 4.5 mg/L (Kreamer 1996 cited in SERA 2004e). The NOEC of 10 mg/L for sub-lethal effects in rainbow 

trout is approximately 100 times more susceptible than bluegill sunfish that has a NOEC of 1,000 mg/L.

Picloram acts as a plant growth regulator. It would not be used to control aquatic vegetation. The acute and 

chronic toxicity of picloram has been assayed in various species of fish. Based on studies, the EPA classified 

picloram acid as moderately toxic to freshwater fish (SERA 2003b).

According to the Ecological Risk Assessments, when applied at either the typical or the maximum application 

rate, picloram poses low risk to susceptible fish species under acute exposure scenarios. Under accidental spill 

scenarios, risks to susceptible fish are high; risks to tolerant fish are low (for both application rates).

Triclopyr is a selective, systemic herbicide used on broadleaf and woody species, including woody species found 

in riparian and aquatic areas, such as saltcedar, willows, and purple loosestrife. Commercial formulations of 

triclopyr may contain the acid form (TEA) or the BEE form; these triclopyr derivatives are evaluated separately 

in the Forest Service Risk Assessment. The risk characterizations for aquatic animals differ for triclopyr TEA and 

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triclopyr BEE. When applied at the typical or maximum application rate, triclopyr TEA poses no risk to fish in 

streams or ponds under acute and chronic exposure scenarios. Under an accidental spill scenario, there would be 

low risk to fish. When applied at the typical rate, triclopyr BEE would pose a moderate risk to fish under acute 

exposure scenarios, and a high risk to fish under a scenario involving an accidental spill into a stream or pond. 

Triclopyr acid would pose a moderate risk to fish under an accidental spill scenario involving the maximum 

application rate. Triclopyr BEE would pose a high risk to fish under acute exposure scenarios at the maximum 

rate, and high risk to fish because of an accidental spill into a stream or pond.

Some effects may be anticipated for fish under certain conditions. While there is a major difference in the 

potential hazards posed by triclopyr TEA forms (which are registered for aquatic use) and triclopyr BEE forms 

(which are not registered for aquatic use) to fish, there are no significant differences among species in terms of 

susceptibility to the various agents. Sub-lethal effects of triclopyr BEE on salmonids occur at concentrations 

between 0.32 and 0.43 mg/L, where fish were lethargic, while behavioral changes to triclopyr TEA would occur at 

200 mg/L. Subchronic toxicity in fathead minnows (at the embryo-larval stages) was observed when the fish were 

subjected to 140 mg/L of triclopyr TEA for 28 days (Mayes et al. 1984, Mayes 1990, all cited in SERA 2003c). 

This study found that survival of these minnows was greatly reduced at this toxicity level.

Although triclopyr BEE is more toxic than triclopyr TEA, the risk of triclopyr BEE to fish is low, as this form will 

rapidly hydrolyze to triclopyr acid, lowering risk to fish.

Summary of Herbicide Effects

The risk characterization process of the Ecological Risk Assessment suggested that chlorsulfuron, diflufenzopyr, 

diflufenzopyr + dicamba, and sulfometuron methyl shows no risk associated with use of these herbicides under 

any of the evaluated scenarios, including accidental direct spray or spill. There is no risk from dicamba exposure 

scenarios except for a low risk for the spill scenario at the maximum application rate. Imazapic does not pose 

a risk to fish, except when directly sprayed over a stream at the maximum application rate. There is no risk to 

fish associated with off-site drift of bromacil or tebuthiuron. Under surface runoff scenarios, diuron can present 

a moderate to high risk to fish if applied at the maximum application rate. The risks to fish associated with 

application of aquatic herbicides to ponds and streams is greater for diquat than for fluridone, which when applied 

at the typical application rate only poses a risk in streams (aquatic herbicides are not typically applied to streams; 

therefore, this is an accidental scenario).

The ALS-inhibiting herbicides evaluated in this EIS are chlorsulfuron, imazapic, imazapyr, metsulfuron methyl, 

and sulfometuron methyl (all but imazapyr are terrestrial herbicides). These herbicides are considered highly 

potent to plants and are applied at low application rates because only small concentrations are necessary to 

damage plants. However, the process they inhibit is unique to plants. There is low risk associated with direct 

spray of imazapic or imazapyr at the maximum application rate. However, this risk is similar to or less than risks 

associated with the other evaluated herbicides, and could be avoided by applying at the typical application rate. 

Their very low typical rates could mean there is less risk of off-site transport associated with their use.

Adjuvants, Degradates, Inert Ingredients, and Tank Mixes

Adjuvants: The BLM reviewed toxicity data for adjuvants, such as surfactants and anti-foam agents, to assess risks 

to fish. In addition, the GLEAMS model was used to evaluate the risks associated with polyoxyethylenamine 

(POEA), a surfactant found in some glyphosate formulations that is more toxic to fish than glyphosate itself. 

This adjuvant is of greatest concern in terms of potential effects to fish. Using the GLEAMS model, the BLM 

predicted the portion of an adjuvant that would potentially reach an adjacent water body via surface runoff.
229

Based on GLEAMS modeling for POEA, risks to aquatic organisms were not predicted for the majority of 

pond and stream scenarios involving exposure to this adjuvant. However, risks were predicted (using the most 

conservative acute endangered species LOC) for applications at a distance of 0 feet from the water body. This 

scenario, which essentially assumes a direct application to the water body with no dilution or drift, is highly 

conservative and highly unlikely under BLM application practices. Risks to Federally Listed and other Special 

Status aquatic organisms in streams and ponds were also predicted for aerial applications of POEA at the 

maximum rate at a distance of 100 feet from the water body. However, it is unlikely that the BLM would apply 

glyphosate formulations containing POEA in an area known to contain Special Status aquatic species. Because 

of a lack of physical chemical property information, POEA was not modeled for leaching properties and runoff to 

water bodies. Therefore, there is some uncertainty associated with risk to fish from this exposure.

Some sources (Muller 1980, Lewis 1991, Dorn et al. 1997, Wong et al. 1997) generally suggest that the acute 

toxicity of surfactant and anti-foam agents to aquatic life ranges from 1 to 10 mg/L, and that chronic toxicity 

ranges as low as 0.1 mg/L. This evaluation indicates that, for herbicides with high application rates, adjuvants 

have the potential to cause acute, and potentially chronic, risk to aquatic species. More specific modeling and 

toxicity data would be necessary to define the level of uncertainty. Use of adjuvants with limited toxicity and low 

volumes near aquatic habitats would mitigate this risk. 

Degradates: Degradates may be more or less mobile and more or less toxic in the environment than their source 

herbicides (Battaglin et al. 2003). Differences in environmental behavior (e.g., mobility) and toxicity between 

parent herbicides and degradates makes prediction of potential impacts challenging. For example, a less toxic, 

but more mobile, bioaccumulative or persistent degradate may have a greater adverse impact due to residual 

concentrations in the environment. The BLM conducted a detailed analysis of degradates for herbicides proposed 

for use under the herbicide treatment program. Several databases, including EPA’s ECOTOX database (EPA 

2009a), were searched, and relevant aquatic toxicity data for degradates were identified and considered in the Risk 

Assessments (Appendix 8).

In most cases, predicted risks to fish from degradates would likely be less than risks from the active ingredients 

diquat, diuron, imazapyr, and metsulfuron methyl predicted in Ecological Risk Assessments. For some degradates 

associated with 2,4-D, diuron, fluridone, and triclopyr, selected aquatic species may be more susceptible to the 

degradate than to the active ingredient. These findings should be considered in the context of herbicide use 

practices, the concentration of degradate relative to the parent compound, the process of degradate production, 

and the body of available toxicity data. For instance, in most cases, the increased toxicity of the degradate may be 

offset by the fact that only a minute amount of the degradate is produced, which would likely disperse rapidly in 

an active aquatic system.

Other Ingredients: Relatively little toxicity information was found on inert ingredients during preparation of 

the BLM Ecological Risk Assessments. A few acute studies on aquatic or terrestrial species were reported. No 

chronic data, no cumulative effects data, and almost no indirect effects data (food chain species) were found 

for the inerts in ten herbicides examined. However, some of the inerts, particularly the EPA List 3 compounds 

(inert ingredients of unknown toxicity) and unlisted compounds, may potentially be moderately to highly toxic to 

aquatic species (based on information in Material Safety Data Sheets or published data).

Based on GLEAMS modeling of a generalized inert compound in a “base case” watershed, concentrations of 

inert ingredients exceeded concentrations of herbicide active ingredients under all stream and pond scenarios. 

In general, greater exposure concentrations of inerts occurred under higher application rates, exceeding 1 mg/L

for the maximum pond application scenario. These results suggest that inerts associated with the application of 

herbicides may contribute to acute toxicity to fish if they reach the aquatic environment. However, given the lack 

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of specific inert toxicity data, this statement may overestimate their potential toxicity. It is assumed that toxic 

inerts would not represent a substantial percentage of the herbicide, and that minimal impacts to the environment 

would result from these inert ingredients. Standard Operating Procedures and PEIS Mitigation Measures should 

make adverse effects to fish negligible.

Tank Mixes: Risk Assessment analysis of tank mixes indicates that risks to fish vary by tank mix. The risks to fish 

associated with applications of tank mixes of bromacil plus sulfometuron methyl, and diflufenzopyr + dicamba is 

no greater than those associated with applications of bromacil, imazapic, or diflufenzopyr alone. Risks to fish for 

a tank mix of chlorsulfuron and diuron are greater than those for chlorsulfuron (but not diuron) alone, and risks 

for a tank mix of sulfometuron methyl and bromacil are greater than for bromacil applied alone. There is some 

uncertainty in this evaluation because herbicides in tank mixes may not interact in an additive manner; this may 

overestimate risk if the interaction is antagonistic, or it may underestimate risk if the interaction is synergistic. In 

addition, other products may also be included in tank mixes and may contribute to the potential risk.

Invasive Plant Effects

Riparian systems are being invaded by non-native species, which are generally detrimental to native aquatic 

species. Potential adverse effects to aquatic species are also described in part under the Water Resources and 

Wetlands and Riparian Areas sections in this Chapter. Invasive plants are generally less efficient at holding soil 

in place, and cause water-quality problems. Whenever the water quality of a fish-bearing stream is affected, so 

are fish. Specifically, fish are affected by turbidity, sedimentation, loss of large organic debris, loss of shading 

(and associated temperature increases), and exposure to hazardous substances. Erosion increases turbidity and 

sedimentation that can reduce fish feeding success. Severe cases of sedimentation can keep fry (early-stage fish) 

from emerging, or fill in or reduce the deeper pools preferred by fish, especially trout.

In riparian areas, invasive plants (e.g., Himalayan blackberries, reed canary grass, saltcedar, Japanese knotweed) 

often support fewer native insects than native plant species, which could affect food availability for insectivorous 

fish species, such as salmonids. The replacement of native riparian plant species with invasive plants may 

adversely affect stream morphology (including shading and instream habitat characteristics), bank erosion, and 

flow levels. Invasive plants break down the complex natural vegetative physical structure and interfere with 

natural processes.

Problematic invasive plants that could be treated by the BLM using herbicides include water-thyme and Eurasian 

watermilfoils, which are found in ponds, lakes, and streams; and perennial pepperweed, saltcedar, knapweed, 

and thistles, which are found in riparian habitats. These species displace native vegetation and decrease species’ 

diversity. Dense concentrations of aquatic plants can reduce light penetration and lower the concentration of 

dissolved oxygen in the water and can upset the balance of the fish community by providing too much cover 

for small fish (Payne and Copes 1986). Many invasive riparian plants form monocultures that crowd out more 

desirable native plant species.

Treatments that reduce or slow the spread of noxious weeds and other invasive plants would decrease the 

incidence of these adverse effects. Alternative 2 (No Action) is predicted to result in about 1/3 of BLM lands 

in Oregon becoming infested with noxious weeds in 15 years, with Alternative 3 about 1/4, and Alternative 4 

(Proposed Action) closer to 1/5th. These proportions would be expected to apply or be similar for riparian areas; 

weeds could spread even faster in these areas because of flood disturbances, water transport, and affinity of many 

plants for wetter areas.
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Non-Herbicide Treatments Effects

Manual and Mechanical Treatments: Certain manual and mechanical treatments within riparian areas that 

disturb soil, such as grubbing and pulling, carried out over a large area, may lead to increased erosion and stream 

sedimentation. Resultant sedimentation may adversely affect fish by covering eggs or spawning gravels, reducing 

prey availability, or directly harming fish gills, reducing stream carrying capacity for fish. However, the risk of 

harm to aquatic ecosystems due to fine sediment production from manual treatment or use of motorized hand 

tools is low, and short-term, resulting in effects likely to be localized and minor. However, depending on the 

scale of treatment, pulling significant numbers of large plants or treating large riparian areas with motorized hand 

tools may moderately increase the risk to fish. Cut vegetation not in danger of contributing invasive plant seeds 

or sprouting matter to the site (including any cut non-target vegetation) left on the treatment site can reduce the 

potential for erosion and subsequent sediment delivery to streams or other water bodies.

The risk of harm to fish from use of wheeled or tracked machinery will vary, depending on the extent of 

treatment area and proximity to aquatic environments; vehicle tracks can compact soils and divert waters. Fish 

are temporarily affected when water is affected by turbidity, sedimentation, and local increases in surface water 

runoff. However, all wheeled equipment (including OHVs containing spray mix and other herbicide application 

equipment) would normally be kept well away from riparian areas to minimize aquatic effects and the risk of 

water-affecting spills. Some kinds of equipment, such as walking brush-cutters, are designed to minimize ground 

disturbance.

Power-tool use near water can potentially cause water contamination with minor amounts of chainsaw oil or 

minor fuel spill. An oil skim on water, while highly unlikely, can deplete oxygen levels and cause fish kills. This 

effect is more likely for fish living in ponds than for fish living in rivers or streams, since the flow of water in 

streams would move and disperse small amounts of oil.

Directed Livestock: The use of livestock to control invasive plants requires a highly specialized operation, often 

involving animals that are “trained” to forage on the target plant, and usually involving temporary fencing 

to keep the animals within the target area. The livestock species, grazing intensity, and management of the 

grazing animals used to treat invasive plants are different from grazing for livestock production. The specific 

use of livestock in this type of control effort has not been utilized extensively in riparian areas or near aquatic 

ecosystems. Current techniques for using directed livestock as an invasive plant treatment tool are not likely to 

have adverse effects on riparian areas and aquatic environments.

Prescribed Fire for Weed Control: The risk of harm to fish from prescribed fire for weed control depends on fire 

intensity, timing, and land form, among other factors. Prescribed burning has the potential to bare large areas 

of soil, and thus increase both surface erosion and sedimentation of streams. Heavy runoff from burned areas 

can increase water pH, indirectly affecting aquatic biota. Site-specific implementation of Standard Operating 

Procedure would help prevent this method from being used where significant adverse stream effects would occur 

(PER:2-31).

Biological Controls and Seeding/Planting: No adverse effects to fish are anticipated from either of these nonherbicide processes.

Final Environmental Impact Statement, Chapter 4: Fish
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Effects by Alternative – Non-Special Status Fish

Reference Analysis – No Herbicide Use

Under the no-herbicide Reference Analysis, fish would not be affected by BLM-applied herbicides.53 Effects 

could stem from other vegetation treatment methods however. Ecosystem benefits resulting from vegetation 

treatment would be reduced under this strategy when compared to the No Action Alternative (Alternative 2), 

in part because about 2/3 of the noxious weeds cannot be effectively controlled without the use of herbicides. 

Treatment methods, such as mechanical methods and prescribed fire can result in soil disturbance and 

sedimentation in aquatic bodies, and retreatment in the same areas is more likely because a single treatment is less 

likely to adequately achieve control.

Specifically, it is often difficult to control or eradicate some species, such as aquatic species and those that 

resprout from rhizomes, by means other than herbicide application. For example, Eurasian watermilfoil forms a 

dense mat that crowds out native aquatic plants and degrades fish habitat (Bossard et al. 2000), and in some cases 

herbicide treatments, including the use of 2,4-D, diquat, and fluridone, are more effective than other treatments, 

such as mechanical harvesters that tend to fragment and spread the weed. The only alternatives to herbicide 

treatment of submersed vegetation are mechanical or manual removal; water drawdown on controlled reservoirs, 

lakes, and ponds; and flooding with salt or brackish water. These treatments generally are not as effective as 

herbicide treatments at controlling many invasive aquatic plants (Gettys et al. 2009). Management under the 

Reference Analysis would be most likely to leave some invasive aquatic plants largely uncontrolled, potentially 

resulting in displaced native species and degraded and reduced fish habitat.

Non-herbicidal treatments are generally less effective than herbicides on many terrestrial riparian species as 

well. Knotweed is not controllable without using herbicides because the plant has roots and rhizomes that extend 

to depths of up to seven feet and spread out over distances of 20 feet or more. Bennett (2006), after reviewing 

several methods used to eliminate blackberries, found that without the use of herbicides, projects were generally 

not successful at eradication nor cost effective.

Without the use of herbicides, noxious weed populations are projected to increase 14 percent per year and occupy 

2.7 million more acres of BLM lands in 15 years than the No Action Alternative (Alternative 2). The spread 

of noxious weeds and other invasive plant populations would cause further damage to susceptible native plant 

communities, including riparian communities that directly or indirectly provide habitat for fish.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Effects to fish would be similar to those that are presently occurring. Sixteen of the 120 State listed noxious weed 

species are not effectively controlled by the four herbicides or other methods available under this alternative, and 

herbicides cannot be used to treat non-noxious invasive plants.

Herbicide Effects: Based on Forest Service Ecological Risk Assessments, chronic (long-term) and acute (shortterm) exposures modeled for all herbicides in this alternative except acute exposure for glyphosate did not exceed 

the NOEC for any fish. For glyphosate, the Ecological Risk Assessment modeling predicted low to moderate 

risks from acute exposures at typical and maximum application rates.

It is unlikely that the use of herbicides proposed in this alternative would cause fish kills at the concentrations 

likely to occur in water. Mortality to fish is also not expected or likely from operational use, because dilution, 

53 There would still be herbicides in the system, even on BLM lands, because of herbicide use on adjacent lands.
233

degradation, adsorption, and other factors reduce the amount of herbicide that could enter a water body. In rare 

circumstances, high concentrations of herbicides could wash into streams from rainfalls shortly after herbicide 

application along road ditches or other surfaces that rapidly generate overland flows, or because of an accidental 

spill. In such instances, localized fish kills are plausible in small tributary streams or small enclosed water bodies 

where contaminated flows would not be readily diluted. Dicamba presents a risk (low) only for susceptible fish 

under the accidental spill scenario at the maximum rate.

Invasive Plant Effects: Noxious weeds would be expected to continue spreading at about 12 percent per year 

on BLM lands in Oregon. In addition, the inability to treat other non-noxious invasive plants with herbicides 

increases the likelihood additional plants will become well established before they are declared noxious weeds. 

The spread of invasive plant populations at current rates would continue to cause damage to native plant 

communities, including riparian communities, which directly or indirectly provide habitat for fish. The continued 

spread of invasive plant populations will have harmful effects on fish.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Herbicide Effects: Based on Ecological Risk Assessments, chronic (long-term) and acute (short-term) exposures 

modeled for chlorsulfuron, clopyralid, fluridone, hexazinone, imazapic, metsulfuron methyl, and sulfometuron 

methyl (seven of the herbicides added by this alternative to the four discussed in Alternative 2 – No Action) 

did not exceed the NOEC for any fish (Table 3-14 and Table 3-15). Two herbicides in this alternative and not 

included in Alternative 2, imazapyr and triclopyr, were found to have high risk under certain scenarios. Imazapyr 

was found to have high risk for susceptible (coldwater) fish in an accidental spill scenario at the maximum 

exposure. Modeling for triclopyr found a high risk to susceptible (coldwater) fish in the accidental spill scenario 

at both the typical and maximum application rates, and a high risk for susceptible (coldwater) fish in the acute 

exposure scenario.

Based on the results of the Ecological Risk Assessments, it is unlikely the fish species would be harmed by 

herbicide use proposed in this alternative.

As this alternative proposes to treat 13,600 more acres than Alternative 2 (No Action), it could potentially result 

in greater exposure to fish. However, 12,600 acres of this increase will occur in eastern Oregon uplands generally 

away from streams. The BLM’s ability to use up to nine additional herbicides (see Table 3-3), and thus reduce 

the total pounds of herbicide applied by 35 percent (Table 3-4), would reduce risks to fish when compared to the 

No Action Alternative (Alternative 2). For example, fluridone shows no risks to fish at typical application rates 

and could replace other aquatic herbicides currently used by the BLM on public lands. In addition, the use of 

glyphosate would decrease more than 50 percent under this alternative.

Imazapic, chlorsulfuron, clopyralid, and metsulfuron methyl would primarily be used east of the Cascades, but 

could still provide benefits greater than those under the No Action Alternative. These herbicides could be used to 

control biennial thistles, annual and perennial mustards, knapweeds, starthistle, and cheatgrass. These invasive 

plant species degrade riparian and upland habitats and can contribute to shortened fire cycles, followed by soil 

erosion and sedimentation.

Under accidental direct spray, spill, and off-site drift scenarios modeled in the Ecological Risk Assessment, 

imazapic presents a very low or no risks to fish, similar to chlorsulfuron, and sulfometuron methyl but lower than 

the risks associated with other herbicides currently being used.

Ecological Risk Assessments for chlorsulfuron, imazapic, and sulfometuron methyl predict no risk to fish from 

direct spray, off-site drift, surface runoff, or accidental spill to a pond (Table 3-14). For the surface runoff 

Final Environmental Impact Statement, Chapter 4: Fish
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scenarios, risks to fish were not predicted for chlorsulfuron, fluridone, imazapic, and sulfometuron methyl. 

Glyphosate and triclopyr do present risk to fish under some application scenarios. Each of the four currently 

available and nine additional herbicides that would be available under this alternative has different properties (e.g., 

mode of action), different suggested uses, and is most effective/least risky in different scenarios. This suggests that 

the more herbicides available for use, the more opportunities there would be to select one or more during projectlevel design that would present the least risk to fish while accomplishing the specific weed control objective.

Fluridone is an aquatic herbicide that would be available under this alternative to control submerged aquatics 

including Eurasian watermilfoils and hydrilla. The fluridone Ecological Risk Assessment (Table 3-15) predicts 

no risk to fish from direct spray in a pond (fluridone is not used in streams). However, the Ecological Risk 

Assessment predicts risk to fish may occur when fluridone is spilled directly into a pond. Fluridone is slow 

acting and is used at low concentrations on both submergent and emergent plants. As the plants die off slowly, 

there is not a large concentration of decaying organic matter added to the water at one time so it is less likely to 

deoxygenate the water and kill fish than other aquatic herbicides.

It is very unlikely that implementation of aquatic vegetation control under this alternative will result in a fish-kill. 

Fish have avoidance mechanisms and are mobile allowing them to move to other parts of a lake or stream in order 

to avoid adverse conditions. However, under certain circumstances such as an accidental spill in an enclosed 

water body or small fish-bearing stream, fish-kills could occur.

The effects of using glyphosate for control of Sudden Oak Death are expected to be de minimus because the 

Biological Assessment specifies use of the less toxic form and specifies other project design criteria protective to 

fish (see the Pest and Diseases section earlier in this Chapter.

Invasive Plant Effects: Under this alternative, the noxious weed spread rate is projected to be reduced to 7 

percent per year, and noxious weeds are projected to infest 1.9 million fewer acres of BLM lands in 15 years 

than the No Action Alternative (Alternative 2). Although Alternative 3 would prevent more invasive plant 

infestations, their continued spread would continue to damage native plant communities, including riparian 

communities that directly or indirectly provide habitat for fish. This continued, albeit reduced, spread would 

have harmful effects on fish.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

This alternative could result in potential adverse effects to fish if subjected to long-term exposure. However, 

acute (short-term) herbicide exposures to aquatic organisms are not likely to result in harm under foreseeable 

conditions, and the expected reductions in adverse fish effects from the additional control of invasive plants 

exceeds the potential herbicide risk to fish.

Herbicide Effects: Based on Ecological Risk Assessments, bromacil, diuron, and tebuthiuron54 modeling predicted 

risks to fish in certain scenarios (Tables 3-14 and 3-15). Bromacil has a low or moderate risk at typical and 

maximum application rates for most scenarios modeled with the exception that it had no risk to fish in the surface 

runoff scenario for a pond or stream. Diuron has high or moderate risk to fish in most scenarios modeled. No and 

low risk to fish from diuron was found for the off-site drift or surface runoff scenarios. For tebuthiuron, no risks 

to fish were recorded except for low risk during an accidental spill to pond at maximum application rate. The use 

of these materials along rights-of-way could pose additional exposure opportunities for fish as roadside ditches 

54 These are the three additional herbicides that would become available under this alternative, in addition to those 

discussed under Alternatives 2 and 3.
235

and unobserved culverts and seeps could lead to nearby streams, particularly if materials are not well bound by 

the onset of the next precipitation event. However, little use of these materials is proposed west of the Cascades 

where these conditions are most likely to be encountered.

Other herbicide use would increase as well. The acres of 2,4-D, glyphosate, and picloram would approach No 

Action Alternative (Alternative 2) levels, as these material would be used to treat native and other non-invasive 

vegetation along rights-of-way and in habitat improvement areas. The risk to fish from herbicides would be 

higher under this alternative than under Alternatives 2 and 3 because of additional acres treated, additional pounds 

used, and use of boom spraying along roads. Required application of Standard Operating Procedures and PEIS 

Mitigation Measures (Appendix 2) minimize this risk, and overall adverse effects are predicted to be less under 

this alternative because of the additional reduction in the spread of noxious weeds. 

Invasive Plant Effects: Under this alternative, the noxious weed spread rate is projected to decrease to 6 percent 

per year, and noxious weeds are projected to infest 2.2 million fewer acres in 15 years than under the No Action 

Alternative (Alternative 2). Although invasive plants would continue to spread under Alternative 4, that spread 

would be minimized and native riparian communities that directly or indirectly provide habitat for fish would be 

more likely to remain uninfested.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Herbicide Effects: As this alternative proposes to treat slightly more acres and use more herbicides than 

Alternative 4 (Proposed Action), there is a slightly greater potential for negative effects to fish. Based on 

Ecological Risk Assessments, diquat has a moderate risk to fish from direct spray to a stream at maximum 

application rates, and high risk for the accidental spill to pond scenario. However, diquat is an aquatic herbicide 

so it is not used where fish kill must be avoided. The Ecological Risk Assessment for diflufenzopyr + dicamba 

found no risks to fish in any of the scenarios modeled.

Although the effects to fish in this alternative are very similar to Alternative 4, this alternative would result in the 

highest likelihood of adverse effects to fish because it proposes the most treatments (300 percent more acreage 

than would be treated with herbicides under the No Action Alternative (Alternative 2), and 68 percent more 

pounds using the typical application rate). However, based on the results of the Ecological Risk Assessments, it is 

unlikely the fish species would be harmed by the herbicide use proposed in this alternative.

Invasive Plant Effects: The spread of invasive plants and its effects on fish habitat would be essentially the same 

as under Alternative 4 (Proposed Action).

Effects by Alternative – Special Status Fish

There are potential risks to Federally Listed, proposed for listing, and other species designated by the BLM 

State Director as Special Status fish species (managed under the Special Status Species Program). Although the 

predicted risks for adverse health effects to individual fish are the same as those predicted for non-Special Status 

fish, the associated population-and species-level effects would be much greater for many Special Status fish 

species because of their limited/fragmented distribution and limited population size. Risks to Special Status fish 

would be minimized by following Standard Operating Procedures and PEIS Mitigation Measures in Appendix 

2 including those specific to Special Status fish, Protective Measures in Appendix 5, and following the BLM’s 

Special Status Species Program policies. 

Final Environmental Impact Statement, Chapter 4: Fish
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 236

The invasion and spread of non-native plant species into aquatic and riparian habitats may affect certain 

populations of Special Status fish. An overview of the ways in which non-native aquatic and riparian plants may 

affect aquatic habitats is presented earlier in this section. Numerous Federally Listed fish are threatened by the 

changes in water quality and flow that may result from weed infestations. Salmon, for example, require a high 

level of dissolved oxygen, which is reduced when aquatic weeds such as Eurasian watermilfoil and water-thyme 

invade an aquatic system. A decrease in dissolved oxygen associated with the encroachment/excessive growth of 

vegetation has also been listed as a threat to the Foskett specked dace in south-central Oregon (USDI 1985b). For 

species such as these, herbicide treatments to reduce coverage of non-native plant species in aquatic and riparian 

habitats would likely improve habitat over the long term. 

Numerous Special Status fish, however, are most threatened by changes in water levels and quality associated 

with development, upslope land use practices, and groundwater pumping, and the expansion of non-native fish 

populations. For most fish, invasions of non-native plant species into riparian and aquatic habitats have not been 

listed in Conservation Strategies and other documents as threats to the species’ survival. For these fish, health 

risks and increased inputs of chemicals into the water associated with herbicide spraying could outweigh any 

habitat improvements resulting from minimized weed infestations. In addition, some herbicide treatments could 

have short-term adverse effects on Special Status fish by killing non-target vegetation and reducing the overall 

cover of riparian vegetation that regulates water temperature through shading. 

Adverse effects to water quality from the spread of invasive plants vary by alternative as described earlier in this 

section. Damage to watersheds, stream banks, and riparian areas by invasive plants is more significant for Special 

Status fish because populations are already weakened or stressed.

A more conservative LOC of 0.05 was used to determine risks to Special Status fish. The potential effects of 

herbicides on Special Status fish could be greater than the effects on non-Special Status fish and other aquatic 

organisms (an LOC of 0.1 was used for non-Special Status species), as shown in Tables 3-14 and 3-15.55 Aquatic 

herbicides with the greatest likelihood of affecting Special Status fish during a normal application to an aquatic 

habitat include diquat and the more toxic formulation of glyphosate. Normal aquatic applications of 2,4-D and 

imazapyr would not pose a risk to Special Status fish.

 

Terrestrial herbicides with the greatest likelihood of affecting Special Status fish because of a spill, drift, 

accidental direct spray into an aquatic habitat, or surface runoff are diuron, picloram, and the more toxic 

formulation of glyphosate. According to Ecological Risk Assessments, there would be no risks to fish associated 

with chlorsulfuron, diflufenzopyr, imazapic, diflufenzopyr + dicamba, or sulfometuron methyl. Dicamba shows a 

risk (low) for susceptible fish in the spill scenario at maximum rates.

Reference Analysis - No Herbicide Use 

There would be no impacts from herbicide exposure from BLM vegetation treatments. Effects from nonherbicide treatments would be similar to those described earlier for non-Special Status fish.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Noxious weeds would continue to spread at current rates, and control of weed infestations in aquatic and 

riparian areas would continue to be limited by the availability of only two aquatic herbicides, glyphosate and 

2,4-D. Current adverse effects to Special Status fish would continue; the degree of benefit to Special Status fish, 

55 Risks for BLM-evaluated herbicides, Table 3-14, were calculated with a lower LOC as described. For FS-evaluated 

herbicides, the “susceptible” category was used as a proxy for special status fish.
237

particularly species that are currently threatened by infestations of non-native plants, would likely be lower than 

under the action alternatives. However, short-term adverse impacts to habitats that support Special Status fish 

(such as increased water temperatures) would be lower as well. The degree of benefits versus impacts to these 

habitats from treatments would largely depend on where the treatments occurred.

Considering acreage alone, it is likely that Special Status fish would be exposed to herbicides far less under 

this alternative than under the other herbicide-use alternatives (Alternatives 3, 4, and 5). However, Standard 

Operating Procedures and PEIS Mitigation Measures protect these species and their habitat from harm under all 

alternatives, which should minimize differences in risk to Special Status species.

Under this alternative, 2,4-D and glyphosate could be used in aquatic and riparian habitats. The herbicides not 

registered for aquatic use (picloram and dicamba) could also be used in riparian areas, provided the herbicide did 

not contact the water and required buffers were implemented. Of these herbicides, only glyphosate is likely to 

pose toxicological risks to Special Status fish during a normal application, but only if the more toxic formulation 

is used, or the less toxic formulation is applied at the maximum application rate. In all areas with Special Status 

fish, typical rate application of the less toxic aquatic form of glyphosate is normally specified. Although there 

would be risks to fish in accidental spill scenarios, continuing to use these herbicides to treat riparian and aquatic 

vegetation would pose a low risk to Special Status fish.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

The greater number of acres expected to be treated in aquatic and riparian habitats than under Alternative 2 (No 

Action) could potentially result in greater impacts to Special Status fish. However, risk from normal use would 

remain minimal, provided only the less toxic formulation of glyphosate was applied at typical application rates. 

The availability of additional herbicides, including five registered for aquatic or riparian use, could reduce risks 

to fish. For example, fluridone shows no risks to fish at typical application rates and could replace other aquatic 

herbicides currently used by the BLM on public lands under certain conditions. Chlorsulfuron, imazapic, and 

sulfometuron methyl pose no risk to fish. Therefore, these herbicides would provide the BLM with additional 

low-risk options for treating near Special Status fish.

Acute (short-term) herbicide exposures to Special Status fish are not likely to result in harm under foreseeable 

conditions under this alternative. Since more terrestrial herbicides would be used under this alternative when 

compared to the No Action Alternative (Alternative 2), risks associated with accidental spill of those herbicides in 

or near a water body, and accidental direct spray into a water body, would be greater. However, the total acres of 

moderate risk herbicides applied would be about one-half of those treated under Alternative 2 (Table 2-5).

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

This alternative includes the use of 2,4-D, dicamba, glyphosate, picloram, clopyralid, diuron, fluridone, 

hexazinone, imazapic, imazapyr, metsulfuron methyl, sulfometuron methyl, and triclopyr State-wide, and 

bromacil, chlorsulfuron, and tebuthiuron east of the Cascades. As this alternative proposes to treat more acres and 

use more herbicides, there are greater positive and negative effects to Special Status fish.

The herbicides used in riparian and aquatic areas to treat invasive vegetation, as well as the quantity of herbicides 

used and the methods of application, would not be substantially different than for Alternative 3. Risks to Special 

Status fish from these herbicides and uses would remain minimal at typical rates, because only aquatic-labeled 

glyphosate would be used near water bodies. However, since additional, generally more toxic herbicides would 

Final Environmental Impact Statement, Chapter 4: Fish
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 238

be made available for native and other non-invasive vegetation treatments (albeit away from water bodies), risks 

associated with accidental spill of those herbicides in or near a water body, and accidental direct spray into a water 

body, would also be greater than under Alternatives 2 and 3.

Roads often parallel streams or have multiple stream crossings. Roads often act as extensions of stream networks 

with roadside ditches sometimes having low but measurable concentrations months after treatment (Wood 

2001). Herbicides used along road rights-of-way could reach streams even when buffers to the actual stream are 

applied. Picloram and the more toxic formulations of glyphosate are the biggest risks. Having a greater number 

of herbicides from which to choose, and recognition of this issue during project design, including consideration 

of Special Status species and the application of Standard Operating Procedures and PEIS Mitigation Measures, 

would reduce potential impacts to water quality from herbicide applications.

Acute (short-term) herbicide exposures to aquatic organism are not likely to result in harm under foreseeable 

conditions, and the expected reductions in adverse fish effects from the additional control of invasive plants 

exceeds the potential risk to fish from the proposed herbicide applications.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Based on acreage, this alternative would entail the greatest amount of herbicide exposure to Special Status fish. 

Although a slightly greater amount of herbicides would be used in aquatic and riparian habitats than under the 

other alternatives (most additional treatments under Alternatives 4 and 5 would be outside of riparian areas), 

risks to Special Status fish from their normal use would remain minimal, provided glyphosate was only applied at 

typical application rates, and only the less toxic formulation was used. However, since more terrestrial herbicides 

would be used under this alternative as well, risks associated with accidental spill of those herbicides in or near a 

water body, and accidental direct spray into a water body, would also be greater than under the other alternatives.

Diquat would become available under this alternative. Diquat would likely be used only where the other five 

aquatic herbicides would not accomplish weed control objectives, specifically giant salvinia if it were to be found 

on BLM lands in Oregon. Direct spray would pose low to high risks to fish (including Special Status fish) during 

a normal application, depending on the application rate and type of aquatic habitat. Use of diquat in place of other 

aquatic herbicides would likely increase the incidence of adverse health effects to aquatic organisms per area 

treated. Diflufenzopyr + dicamba, which would also become available under this alternative, poses no risk to fish. 

Acute (short-term) herbicide exposures to aquatic organisms are not likely to result in harm under foreseeable 

conditions. 

Cumulative Effects

Existing Controls

A number of Federal, State, local, and tribal resource management and monitoring programs have been 

established to protect environmental resources and, in cases where there is existing environmental impairment, 

to effect restoration. The assessment of cumulative impacts recognizes the existence of these programs and 

assumes that the mandate under which each program was established will continue. The cumulative effects 

analysis assumes in part that these programs effectively avoid or mitigate the environmental impacts that they 

are designed to address.
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Fish as an Indicator of Ecosystem Health

Fish, the dominant aquatic vertebrate in the analysis area, constitute a key component of aquatic systems on public 

lands in Oregon. Fish are a critical resource to humans and as such have influenced the development, status, 

and success of social and economic systems in Oregon. Aquatic organisms such as insects and other aquatic 

invertebrates provide food for fish. The health of fish and other aquatic organisms is often indicative of the 

health of the watershed. Fish and other aquatic organisms are often more susceptible than humans and wildlife to 

herbicides and other chemicals in their environment, and thus can be an indicator of the water quality standards. 

Today, the rapid expansion of invasive plants across public lands is a threat to ecosystem health and one of the 

greatest challenges in ecosystem management.

Past Effects and Their Accumulation

Cumulative impacts to fish and the lakes, ponds, wetlands, and riparian areas that provide habitat for fish on 

public lands and throughout Oregon have occurred from human-caused disturbance factors, including natural 

resource extraction, recreation, fire exclusion, construction of roads, dams, and hydropower facilities, agriculture, 

and urbanization. In addition to these and natural disturbances, use of wetland and riparian areas by livestock and 

wild horses has degraded habitat values. Water withdrawal from ditches and diversions have affected fish habitat 

on public and other lands. Overfishing has been blamed for the declines in some fish populations (USDA, USDI 

2000a). The introduction of non-native game fish has also affected some native fish populations.

BLM surveys show that about 50 percent of inventoried riparian habitat on BLM lands in Oregon lack 

characteristics necessary for “proper” functioning condition (see Wetlands and Riparian Areas section). Proper 

functioning riparian areas have the necessary physical and structural components to dissipate stream energy 

associated with high water flows, as well as conditions that support a diverse and healthy population of fish and 

other aquatic organisms.

The permitting process and the regulatory environment for protecting fish have improved over time and are 

generally effective. Proper construction and placement of bridges and culverts have greatly reduced adverse 

effects but have not eliminated them. Little is known about the effects of water withdrawals from lakes on fish. 

Some fish have been harmed or killed during water extraction, but these numbers have been small and have 

not accumulated (USDI 2005d). The rate of loss of wetland and riparian areas has slowed with the passage of 

Federal, State, and local regulations that strive to protect wetland and riparian habitat. There has been some 

improvement in the functional quality of wetland and riparian areas on public lands in Oregon, a trend that is 

likely to continue.

During the early years of the BLM, most resource conservation and management was focused on upland sites. 

An increased emphasis on wetland and riparian habitat protection began in the 1960s. In the 1970s, FLPMA was 

passed (1976) and the BLM began preparing land use plans to better manage natural resources on public lands. 

Land use plans set goals and objectives for natural resource management and identify priority watersheds on 

which to focus restoration efforts. In addition, the BLM is assessing the condition of wetland and riparian areas, 

and conducting restoration efforts in areas that are less than proper functioning.

Past weed control efforts by the BLM, other Federal and State agencies, private landowners, and/or businesses 

(particularly the agricultural industry) have resulted in the application of thousands of tons of herbicides and other 

pesticides to the environment (see Table 4-1). As discussed earlier in this section, some of these herbicides break 

down relatively quickly in the environment or are not harmful to aquatic organisms at typical application rates. 

However, some herbicides are harmful to aquatic organisms, and may persist in the environment for many months.

Final Environmental Impact Statement, Chapter 4: Fish
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Invasive Plants

The spread of invasive plant species is one factor that degrades habitat for aquatic organisms. Within riparian 

shrublands, there has been extensive conversion to areas dominated by exotic grasses and forbs. This conversion 

has made these areas more susceptible to fire (which further degrades the resource) and reduced their value to 

aquatic organisms (USDA, USDI 2000a). BLM efforts to restore watersheds including managing and controlling 

noxious weeds and other invasive vegetation would help to reduce erosion and sedimentation and restore native 

plant communities. Restoration of native vegetation should improve riparian habitat and moderate stream 

temperatures and water flows. In addition, the ability of the BLM in Oregon to use aquatic herbicides to control 

aquatic weeds would benefit lakes and ponds and the aquatic organisms that use these habitats.

Streams cross multiple jurisdictions, including private land, along their entire course. In many cases the condition 

of the stream habitat off of public lands and on private or other jurisdiction lands is unknown and could be of 

lower quality. Dams and other diversions found in the Columbia River and most other major rivers in Oregon 

also limit access to upriver habitats and alter occupied habitats for certain anadromous fish and other species. 

Thus, restoration of native vegetation and natural ecosystems may be most immediately beneficial to resident fish 

rather than migratory fish that travel off public lands to meet part of their life requisites (USDA, USDI 2000a).

Cumulative Effects of the Alternatives

Although herbicide treatments can lead to the harm or even death of fish and aquatic organisms, application of 

herbicides is not expected to result in significant mortality to fish. However, while the amount of herbicides 

expected to reach water is expected to be very low under any of the alternatives, and site-specific treatment design 

and required Endangered Species Act consultation will attempt to prevent adverse effects to Federally Listed 

species, the BLM cannot conclude with certainty that herbicides could not potentially reach fish-bearing streams 

and cause adverse effects.

Most studies of herbicide effects on fish observe the effect of short-period exposures to high concentrations 

of herbicides, rather than the low concentrations over an extended period more likely to be found in streams, 

lakes, and ponds. Therefore, chronic effects to fish would not be readily apparent. There is also potential for 

an accidental spill or inadvertent improper use of herbicides to result in the contamination of water, thereby 

adversely affecting fish.

The adverse effect of invasive plants is apparent and growing rapidly. Based on the number of acres treated, 

short-term adverse impacts are nearly the highest under Alternative 4 (Proposed Action). However, long-term 

improvements to the health and productivity of fish would be greatest under Alternative 4 and least under the 

Reference Analysis and Alternative 2 (No Action). The number of acres treated under Alternatives 4 and 5 and their 

associated short and long-term effects would be similar, while Alternative 3 would treat fewer acres than the Proposed 

Action but probably has the lowest likelihood of adverse effects to fish. Most treatments under the Proposed Action 

would occur on uplands, but fish would also benefit from upland treatments located near aquatic habitats.

Herbicide use already occurs on BLM and other Federal, State, and County lands, private forestry lands, 

rangeland, agricultural land, utility corridors, and road rights-of-way. Table 4-1 shows a comparison of the 

pounds of herbicides projected to be used by the BLM under Alternative 4 (Proposed Action), with the pounds 

of those same herbicides used on all ownerships statewide in 2008. The proposed use of herbicides by BLM is 

a small amount of the total use in the State or even any large watershed, given the mixed ownership. This use, 

conducted under the Standard Operating Procedures and PEIS Mitigation Measures, and following site-specific 

analysis and appropriate consultation, is unlikely to contribute substantially to downstream effects.
241

Final Environmental Impact Statement, Chapter 4: Wildlife Resources

Wildlife Resources

Affected Environment

This section addresses the amphibians, birds, mammals, mollusks, aquatic and terrestrial invertebrates, and 

reptiles found on BLM lands in Oregon, collectively called wildlife.56 Over 700 species have been documented 

in the State (all ownerships) including 31 amphibians, 478 birds, 139 mammals, 35 reptiles, and an uncountable 

number of invertebrates (Johnson and O’Neil 2001:2). In addition to resident wildlife, the Pacific Flyway57, 

covering much of Oregon, serves migratory birds. Federally Listed and other Special Status species receive 

special protection during management activities as needed (Appendix 5). For the BLM in Oregon, these include 

13 amphibians, 45 birds, 24 mammals, 2 reptiles, and more than 60 invertebrates (mollusks, arthropods, etc.). 

Conservation Measures included in Appendix 5 and referenced in the PEIS Mitigation Measures in Appendix 2 

apply to Federally Listed and other Special Status species and their proposed or designated critical habitat. 

Within the range of the northern spotted owl, additional species are subject to Survey and Manage requirements. 

These requirements generally include management for population persistence at known sites and, for those whose 

characteristics make clearance surveys practical, pre-disturbance surveys prior to potentially harmful management 

activities. The potential for herbicide exposure is somewhat reduced for species included in Survey and Manage 

because all are believed to be late-successional or old-growth forest associates (or remnant snags and logs). Most 

Survey and Manage species deemed at risk from management activities and locatable with surveys have also been 

designated as Special Status species.

Birds, particularly migratory birds, have experienced precipitous declines since European settlement due to 

multiple causes, including habitat loss, over-utilization, and more recently, changes to natural disturbance patterns 

(Hunter et al. 2001, USDI 2008e). Invasive plants (and animals) contribute to their decline. Migratory birds are 

also subject to the Migratory Bird Treaty Act. BLM management under this Act focuses primarily on long-term 

habitat conditions (USDI 2009b), and provides guidelines when projects may affect populations or their habitats. 

In addition, BLM is a partner in the Partners in Flight cooperative and considers Partners in Flight guidelines, 

conservation strategies, and technical reports in project planning and implementation.

Oregon BLM supports a rich assemblage of mammals. They include big game species such as big horn sheep, 

elk, deer, pronghorn, black bear, cougars, coyotes, and many small-to-medium sized mammals such as mustelids 

(weasels, fishers, martens, skunks), rodents (squirrels, mice, rats, shrews, rabbits) and bats. Mammal populations 

and distributions in Oregon have been influenced by management and a variety of anthropogenic and natural 

habitat alterations. Mammals that are adaptable and tolerant of human activities, such as coyotes, have increased 

in number and distribution. Those that are restricted to unique habitats (such as big hornsheep or pronghorn) have 

decreased.

Invertebrate biodiversity and habitat relationships are poorly researched (King and Porter 2005). Lattin (1993) 

estimates that 6,000 arthropod species may be found in Pacific Northwest old growth forests. Over 3,400 

different species are known from a single 6,400 ha site in Oregon, but information on them is rudimentary. There 

are three Federally Listed invertebrates in Oregon (Appendix 5). Microorganisms are discussed in the Soil 

Resources section in this Chapter.

56 Fish may also be considered wildlife, but they are covered in a separate section.

57 The Pacific Flyway is a major north-south route of travel for migratory birds in the Americas, extending from Alaska 

to Patagonia. Every year, migratory birds travel some or all of this distance both in spring and in fall, following food 

sources, heading to breeding grounds, or travelling to overwintering sites.
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The Oregon Special Status Species Program list, which includes all Federally Listed species, currently includes 

14 Lepidoptera. Remaining populations of these rare butterflies and moths are in fragmented remnants of habitat, 

and population size is very low in most occupied locations (Schultz 2001, Stoner and Joern 2004). The adult 

stage is very short; the entire nectaring period of a small population of some butterflies can be less than 10 days. 

However, individuals of larger populations generally mature at different times, which extends that population’s 

nectaring season. The history of other life phases and their habitat relationships are less known. Some, but not 

all, Lepidoptera are affiliated with specific native plants.

Adult honeybees are used as a surrogate for invertebrates in Risk Assessments. Exotic (non-native) bees have 

been shown to favor exotic plant species, and can differentially allow the exotic vegetation to compete against 

native plants (Goulson 2003). There are more than 3500 species of native solitary bees in North America, and 

many more invertebrate native pollinators that can be influenced by weeds and weed treatments (Greer 1999). 

The balance of invertebrates (predators, herbivores, and nectar-feeders) can be disturbed if too much of one group 

of plants (for instance, broad-leaf or flowering forbs) are removed during their life cycle or native invertebrates 

may be replaced by non-native species if the spread of invasive plants is not controlled.

Mollusks are prey for birds and small mammals (Dunk et al. 2004) and serve other important ecological functions 

by breaking down vegetative litter. From a global conservation perspective, mollusks represent 20 percent of all 

threatened animals, and 37 percent of known animal extinctions since 1600 A.D. (Seddon 1998 cited in Dunk et 

al. 2004). Approximately 69 percent of freshwater mussels in North America are extinct, imperiled, or vulnerable 

to extinction (Stein et al. 2002). Most Oregon mollusks are food generalists, and do not seem to be affiliated 

with unique plant types (Duncan, N. pers. comm.). They are active and most vulnerable during wet times of the 

year. Snails and slugs have moist skin that can make them more susceptible to toxic qualities of water-dissolved 

chemicals. Some herbicides have low toxicity to mollusks.

BLM lands in Oregon support both terrestrial and aquatic forms of amphibians (frogs and salamanders), which are 

moist-skinned cold-blooded animals that breathe through their skin. Diverse habitats on BLM lands in Oregon 

also support a wide variety of reptiles (snakes, turtles, and lizards). Like amphibians, they are cold-blooded 

animals, but unlike amphibians, have scaly skin and are more tied to terrestrial habitats such as rock outcrops. 

Reptiles and amphibians are collectively called “herptiles.”

There are several weeds thought to adversely affect herptiles including Eurasian watermilfoil, purple loosestrife, 

saltcedar, and cheatgrass (Pilliod and Wind 2008). None of the herptiles are currently Federally Listed. 

Habitat connectivity among populations is a concern for all the herptiles (Pilliod and Wind 2008). Restricting 

management activities around water offers some protection for the species that use riparian or water habitats, but 

both reptiles and amphibians move well away from waterways during their life cycle. (Not all herptiles are water 

associated.) Amphibian declines have received more attention in terms of research and publicity, but Gibbons 

et al. (2000) suggests reptiles may be exhibiting declines that are even more precipitous. Both are adversely 

impacted by invasive plants (including invasive fauna as well as weeds) (Hinton and Scott 1990 cited in Gibbons 

et al. 2000), and are vulnerable to the treatments to control weeds. Reptiles, particularly the Special Status 

painted turtle and western pond turtle, have long seasonal metamorphosis periods when they are particularly 

susceptible to all types of management activities.

The natural environment is in constant change due to natural events: seasonal and temporal climate, successional 

development, fire, wind, drought, flood, insect, and disease. Nearly all Oregon native wildlife is dependent 

upon some mosaic of habitat created and maintained by those natural disturbances. Anthropomorphic (human) 

activities have complicated the disturbance pattern and brought irreversible changes to the natural environment. 

Humans have introduced non-native plants and animals—including both beneficial and invasive plants. 
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Wildlife Considerations by Biome

Sagebrush Steppe

BLM lands currently account for 70 percent of the remaining sage grouse habitat in Oregon (Hagen 2005). 

Shrubland and grassland birds, representing an important component of the biodiversity of the western United 

States, are declining faster than any other group of species in North America (Saab and Rich 1997, Paige and 

Ritter 1999, Dobkin and Sauder 2004). Species dependent on sagebrush ecosystems (Brewer’s sparrow, Sage 

Sparrow, Sage Thrasher) may be important predictors of ecological degradation. The sagebrush ecosystem 

throughout the Great Basin has been described as one of the most endangered in the United States (Noss et al. 

1995). Several authors identify invasive plants as one risk factor (Wisdom et al. 2005:6, Paige and Ritter 1999:8). 

Connelly et al. (2004) reported 31 percent of original sage grouse habitat has been converted to areas dominated 

by invasive cheatgrass, medusahead, knapweed, and yellow starthistle.

In a central Nevada study, Wisdom et al. (2005) documented 26 bird species and 28 mammals that use sagebrush 

lands for cover and food. Vander Haegen et al. (2001) concluded that 49 of the 103 species (44 birds, 26 

mammals, 20 reptiles, 9 amphibians) in the sagebrush biome may be sagebrush obligates. Amphibian species 

richness and density in sagebrush ecosystems is low due to dry conditions and lack of open water. Vander Haegen 

et al. (2001:239) documented that sites dominated by native plants have more closely associated wildlife habitat 

relationships than those dominated by exotics. 

Many high desert species time their activities to avoid climatic extremes to allow them to capitalize on spotty 

resources such as food or water when they are available. During times of scarce resources or harsh weather, 

species such as marmots, pygmy rabbits, ground squirrels, and burrowing owls may burrow or estivate. They can 

be especially vulnerable to herbicide exposure if limited food or water is contaminated during their metabolically 

active period when they are ingesting large amounts of food or water in a short time. 

Sagebrush habitats dominated by cheatgrass or medusahead monocultures do not provide usable habitat for sage 

grouse and other sagebrush related species. Rowland et al. (2005) evaluated 40 vertebrate species in the Great 

Basin and Nevada for risk to displacement from cheatgrass by using risk models and quantifying habitat for those 

species. They described 36 percent of habitat at high risk and 25 percent at moderate risk of displacement from 

cheatgrass (Rowland et al. 2005:156). All but five of those species occur on BLM lands in Oregon (although the 

Oregon percentages of habitats at risk would be different). Spotted knapweed and many other noxious weeds also 

degrade wildlife habitat in the sagebrush biome. The increase in invasive annual grasses has increased wildfire 

risk as compared to the native shrubland. Rabbitbrush can sprout after a fire that would kill sagebrush (Hammond 

1995 cited in Montana FWP 2008), causing rabbitbrush to be more prevalent than would be found in a healthy 

sagebrush community. Western junipers have increased in sagebrush-dominated communities at higher elevations 

to further degrade sage grouse (Hagen 2005) and mule deer habitat (Clements and Young 1997). A diverse mosaic 

of different sagebrush species and other shrubs is described for healthy sagebrush systems (Rowland 2004).

Eastern Forest

Wildlife communities are relatively unstudied in the eastern forests, as compared to coastal west side forests, 

or east side riparian communities, and much of the limited research has focused on ungulates (Sallabanks et al. 

2001). Wildlife habitat matrices (Johnson and O’Neil 2001) identify 287 vertebrate species associated with (but 

not necessarily obligates of) east side interior forests and woodlands, which is fewer species than riparian or west 

side forests, but more species than those associated with alpine/subalpine habitats. The eastern dry forest hosts 

over a dozen amphibians, 130 birds, 80 mammals, and 20 reptiles. The majority of birds in the Eastern Forest 

biome are foliage-gleaners that glean insects and fruit from vegetation—not from the ground (Sallabanks et al. 

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2001). Herbivory (domestic and wild ungulates) has influenced the understory vegetation in eastern dry forests 

by suppressing shrub canopies and biomass accumulation, particularly through selective suppression of N-fixing 

plants (Sallabanks et al. 2001).

East Side Riparian

This biome is specific to the east side in this EIS, but many of the riparian relationships remain true in west 

side riparian habitats as well. Riparian areas are diversity “hotspots,” supporting some of the richest species 

assemblages of any habitat association (Kauffman et al. 2001). Riparian zones are critical wildlife habitats in the 

high desert of southeast Oregon (Thomas 1979), and the Blue Mountains (Thomas 1979). Thomas identified 285 

of the 378 terrestrial vertebrate species in the Blue Mountains use or are directly associated with riparian habitats. 

Over 80 bird species were documented in a 1.5-mile stream reach in northeast Oregon (Kauffman et al. 1982). 

Kauffman et al. (2001) reported 319 of 593 (53 percent) of wildlife species in Oregon and Washington were 

riparian associates, including many wildlife species included on the Special Status Species Program list.

Siskiyou

This biome has a diversity of wildlife and habitats not usually found in such a limited area. Oregon Department 

of Fish and Wildlife (2005) identifies the Siskiyou mixed conifer forests and woodlands as the most diverse 

forest habitats in Oregon. The Klamath Mountains are considered a herptile “hotspot” by Bury and Pearl (1999), 

supporting 38 native species of amphibians and reptiles, higher than any similar-sized mountain range in the 

Pacific Northwest (Olson et al. 2001). Sixty-five Special Status species are documented or suspected in the 

Siskiyou Biome. The highest avian species richness west of the Cascade crest in Oregon and Washington occurs 

in the Klamath Mountains (Ralph et al. 1991). The Klamath-Siskiyou ecoregion is an area of “extraordinary 

biodiversity,” rated “among the world’s most outstanding temperate coniferous forests” (DellaSala et al. 1999). 

DellaSala et al. (1999) analyzed 2,377 terrestrial animals (including snails, butterflies, birds, mammals, reptiles 

and amphibians), and 168 (or 7 percent) were found nowhere else.

Western Forest (including riparian)

More than 300 vertebrate species are associated with the structurally diverse Oregon western forest biome, 

making it one of the most species-rich areas in Oregon (Olson et al. 2001). Amphibians make up approximately 

13 percent of the total wildlife species in the montane region (which includes the Willamette Valley and Siskiyou 

Biomes in this EIS) (Olson et al. 2001). Mollusks (snails and slugs) are abundant in number and diversity in the 

moist habitats of the western forest biome.

Road density is high, and most BLM lands are in a checkerboard ownership pattern interspersed with private 

industrial lands or rural residential. The patchiness that results from land use and ownership patterns has 

fragmented older forests which serve as habitat for species such as the Pacific-slope flycatcher, varied thrush 

and Vaux’s swifts (Brown 1985), but this fragmentation also provides edge and structural diversity for many 

other wildlife species such as willow flycatchers, white-crowned sparrows, song sparrows and spotted towhees. 

Microhabitats in the lush moist vegetation next to water support many forest riparian species (bats, shrew, marten, 

waterfowl, and amphibians).

The checkerboard ownership, intensive land use, and extensive road network increases the risk of invasive plant 

establishment. Some weeds such as Himalayan blackberry and Scotch broom dominate large portions of the 

western forest landscape. The large amount of water close to human activity also facilitates introduction of waterassociated noxious weeds, such as purple loosestrife and yellow flag iris, which threaten the viability of the many 

aquatic species in this biome.
245

Willamette Valley

Less than one percent of the BLM lands in Oregon are in this biome, but nearby BLM lands in the Western Forest 

Biome can be similar to this biome. Habitat connectivity is one of the greatest concerns for wildlife associated 

with the Willamette Valley, and isolated populations of many rare species remain. Invasive plants are a primary 

factor adversely affecting survival of isolated populations of rare wildlife in the Willamette Valley.

Oak Habitats

There are oak woodland components in all of the biomes in western Oregon. Oak habitats are important habitat 

to many Oregon wildlife species. The ODFW has recognized the importance of this habitat in the Oregon 

Conservation Strategy (ODFW 2005). Oaks are important to wood ducks, band-tailed pigeons, California quail, 

varied thrush, jays, Lewis and acorn woodpeckers, black bear, squirrels, mice, raccoons, and deer (ODFW 

2005). Oak habitats generally have open grass-dominated understories and most have been degraded by annual 

grasses and exotic shrubs to varying degrees. Oaks also have shallow root systems, making them vulnerable to 

mechanical disturbance. Non-native species can suppress the seedlings of oaks, pines and other native species 

(Polster 2004).

Environmental Consequences

The likelihood of significant adverse effects to wildlife from contact with the herbicide uses proposed in the 

action alternatives is negligible at the population scale. The herbicides are formulated to affect plants, and have 

been selected to have some of the lowest (or no) demonstrable wildlife toxicity of licensed herbicides, do not 

bioaccumulate in wildlife, and are quickly degraded in wildland settings. The EPA manual summarizes “Many 

modern herbicides kill weeds selectively by impairing metabolic processes that are unique to plant life. For this 

reason, their systemic toxicities in mammals are generally low. The water-soluble herbicides are not retained in 

body tissues for long periods, as were the old lipophilic organochlorine insecticides such as DDT.”

Risk Assessments (Chapter 3 and Appendix 8) indicating moderate or high risk to wildlife help guide application 

of buffers and other measures to reduce the likelihood of contacting individual animals with hazardous doses. 

Requirements for site-specific pre-project clearances for Federally Listed and other Special Status species also 

help prevent adverse effects to rare species, providing habitat and/or occupancy information to project planners 

so protection measures can be prescribed. Local biologists would use herbicide Risk Assessments that consider 

Special Status species to be 10-times more susceptible to herbicides than other wildlife, to help choose herbicides 

with lesser toxic risk to that particular class of rare species or choose more selective application methods to avoid 

or reduce herbicide contact. Despite efforts to reduce exposure, an occasional non-Federally Listed wildlife 

individual may be exposed to doses above the LOC. Impacts would vary by individual and circumstance, but 

adverse effects would not be expected to be significant to the population level. Similarly, the few wildlife Survey 

and Manage species not requiring pre-disturbance surveys may be harmed if they are sprayed. 

Four categories of potential effects are addressed in this section; a) the potential for adverse health effects from 

the herbicides, b) effects of habitat change either from the spread of invasive plants, or c) as collateral damage 

from the weed treatments, and d) disruption effects (noise and other disturbances) from the vegetation treatments. 

The responses of wildlife species and wildlife communities to habitat changes and to disturbance can be variable, 

complex, interactive, and difficult to accurately predict.

Final Environmental Impact Statement, Chapter 4: Wildlife Resources
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Effects Common to All Alternatives

Effects from direct contact or ingestion of herbicides

Herbicides have the potential to directly harm wildlife individuals, populations, or species (USDA 2005a) through 

toxic reactions. Terrestrial animals might be exposed to any applied herbicide from direct spray, the ingestion 

of contaminated material (vegetation, prey species, or water), or indirect contact with contaminated vegetation. 

Aquatic animals can be exposed to the six herbicides approved for aquatic use (2,4-D, diquat, fluridone, 

glyphosate, imazapyr and triclopyr), and from off-site drift or runoff from terrestrial herbicides.

Toxic effects can include death, damage to organs, changes to body weight or growth rates, reduced reproduction, 

reduced survival of offspring, increased risk of predation, and behavioral (sub-lethal) changes that reduce fitness.

In practice, most BLM weed treatment would be specifically targeted at weeds through direct spray or hack 

and squirt, or at native and other non-invasive vegetation along rights-of-way through boom applications, and 

not applied to extensive acreage across all occupied wildlife habitat. It is likely that larger animals and birds 

would avoid the treatment area during treatment because of noise and activity. Animals that temporarily leave 

the treatment area have reduced risk of directly ingesting the herbicide while grooming, or from ingesting 

herbicides on vegetation or prey (insects or other animals that were directly sprayed), because most of the 

herbicides proposed in this EIS have a very short active period where wildlife toxicity could occur. The few 

studies of herbicides on mollusks indicate they have relatively high resistance to toxic effects of herbicides in the 

environment, although their moist skin facilitates exposure to herbicides in soil and water.

Standard Operating Procedure buffers on wetlands and riparian habitats can reduce risks to herptiles in their 

aquatic form, but may not be large enough to protect herptiles from exposure when they are in terrestrial habitats. 

Turtles and frogs use upland habitat several hundred feet or more from water at certain times of their lives (Bishop 

and Pettit 1992 cited in Govindarajulu 2008). Most of the limited research of herbicides on amphibians has 

been on tadpoles or fish surrogates. Several recent studies of herbicide effects on amphibians suggest adverse 

effects of glyphosate, but the studies used a commercial version of glyphosate that included the surfactant POEA 

(Relyea 2005a, b, Relyea et al. 2005, Relyea 2009). Aquatic animals in water are more vulnerable to exposure 

from herbicides used for aquatic vegetation than terrestrial species because they are less likely to find untreated 

alternate habitat for refugia, although species and developmental stages vary significantly in their susceptibility.

Some sessile animals, such as mollusks and other invertebrates, ground-dwelling mammals, or pre-fledgling birds 

could be restricted to the treatment area. These organisms could be adversely affected by broad scale treatments 

using herbicides with moderate to high toxicity. 

Accidental exposure from off-site drift or spill is also possible. Spill scenarios are included in the Risk 

Assessments. 

Herbicides can be absorbed by plants (and biodegraded in the plant’s processing of the herbicide), are degraded 

by microorganisms rapidly, can be degraded by UV exposure, or are diluted and broken-down into non-toxic byproducts by contact with water or air. Some of the active mechanisms of herbicides are affected by temperature as 

well. Some herbicides have strong affinity to soil particles, which can further reduce active herbicide contact with 

wildlife (see Soil Resources section). Herbicides can change the pH of water that might have indirect effects on 

wildlife that use that habitat (Relyea and Hoverman 2006).
247

ALS-inhibitors: ALS-inhibitors (including chlorsulfuron, imazapic, imazapyr, metsulfuron methyl, and 

sulfometuron methyl, all of which are included in Alternatives 3, 4, and 558) work by inhibiting a biological 

pathway that exists only in plants and not in animals, thus making the ALS-inhibitors among the lowest risk 

herbicides for wildlife (CIS 2009).

Adjuvants: Some sources (Muller 1980, Lewis 1991, Dorn et al. 1997, Wong et al. 1997) generally suggest that 

the acute toxicity of surfactant and anti-foam agents to aquatic life ranges from 1 to 10 mg/L, and that chronic 

toxicity ranges as low as 0.1 mg/L. This evaluation indicates that, for herbicides with high application rates, 

adjuvants have the potential to cause acute, and potentially chronic, risk to aquatic species. More specific 

modeling and toxicity data would be necessary to define the level of uncertainty. Use of adjuvants with limited 

toxicity and low volumes near aquatic habitats would mitigate this risk. 

Endocrine disrupters: The EPA reports effects of endocrine disruption in animals can “include abnormal thyroid 

function and development in fish and birds; decreased fertility in shellfish, fish, birds, and mammals; decreased 

hatching success in fish, birds, and reptiles; demasculinization and feminization of fish, birds, reptiles, and 

mammals; defeminization and masculinization of gastropods, fish, and birds; decreased offspring survival; and 

alteration of immune and behavioral function in birds and mammals.” Of the herbicides analyzed, 2,4-D and the 

surfactant NPE have been identified as potentially having estrogenic effects (USGS 1998, Bakke 2003). Triclopyr 

and glyphosate have been evaluated for endocrine disrupting effects, and the weight of evidence indicates that 

these herbicides cause no specific toxic effects on endocrine function (SERA 2002). Sulfometuron methyl can 

cause malformations in amphibians (SERA 2004f), but whether the malformations are caused by endocrine 

disruption, cellular toxicity, or other pathways has not been reported.

2,4-D is a possible endocrine disrupter (see Endocrine Disrupters) and is one of the more toxic herbicides for 

wildlife of the foliar-use herbicides considered in this EIS. The ester form is more toxic to wildlife than the salt 

form. Ingestion of treated vegetation is a concern for mammals, particularly since 2,4-D can increase palatability 

of treated plants (USDA 2006b) for up to a month following treatment (Farm Service Genetics 2008). Mammals 

are more susceptible to toxic effects from 2,4-D, and the sub-lethal effects to pregnant mammals were noted at 

acute rates below LD50. Birds are less susceptible to 2,4-D than mammals, and the greatest risk is ingestion of 

contaminated insects or plants. The salt form is practically non-toxic to amphibians, but the ester form is highly 

toxic. It can be neurotoxic to amphibians; although not all amphibians respond the same (e.g., toads were more 

susceptible than leopard frogs). There is little information on reptile toxicity, although one study noted no sexual 

development abnormalities. It presents low risk to honeybees (Table 3-15), but little information is available 

for other terrestrial invertebrates. Parasitic wasps may be affected, which could result in changes to community 

structure by favoring damaging insects controlled by parasitic wasps.

Dicamba: No adverse effects on mammals are plausible for either acute or chronic exposures of dicamba. At the 

highest tested rate, there are adverse reproductive effects possible for acute scenarios consuming contaminated 

vegetation. There is little basis for asserting that adverse effects in aquatic animals is plausible. Limited studies 

on dicamba suggest it is practically non-toxic to amphibians and honeybees. Amphibians are as tolerant as the fish 

to the acute toxicity of dicamba, and aquatic invertebrates appear to be somewhat more susceptible to dicamba 

than fish or amphibians. Dicamba has no adverse effects on birds for acute or chronic exposures, although highest 

tested application rates had possible adverse reproductive concerns for acute scenarios involving birds consuming 

contaminated vegetation or contaminated insects (SERA 2004g).

Glyphosate is a low toxicity herbicide, widely used for terrestrial applications and is approved for aquatic use. 

Toxicity to most wildlife groups is very low, so much so that NOAEL levels are used because the LD50 were 

58 Chlorsulfuron is not available west of the Cascades under Alternatives 3 and 4.

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not found at high doses in many cases. Observed effects had to do with reduced feeding efficiency and reduced 

weight gain. Glyphosate adheres to soil, is degraded by soil bacteria, and does not bioaccumulate. Formulas vary 

in toxicity: 1) technical grade (pure) glyphosate is much less toxic than some of the commercial formulations; 

2) commercial glyphosate formulations with the surfactant POEA are similar in toxicity to the surfactant POEA 

alone; 3) glyphosate herbicide formulations, such as Rodeo®, that are formulated without a surfactant are much 

less toxic than formulations with the surfactant POEA; 4) glyphosate herbicides with alternative surfactants 

would be much less toxic to frogs than Roundup Original/Vision® (Mann and Bidwell 1999, Perkins et al. 2000, 

Edginton et al. 2004a, Howe et al. 2004, all cited in Govindarajulu 2008, Relyea 2006). These studies support 

the conclusion that the toxic effect of POEA-containing glyphosate herbicides is due to POEA rather than to the 

active glyphosate ingredient. Ephemeral wetlands important to amphibians may not be protected by standard 

buffers (Govindarajulu 2008). There may be short-term adverse effects to terrestrial and aquatic amphibians 

where POEA formulations of glyphosate are used. Effects would vary by species and by developmental stage 

(Relyea 2005a (lethal impact); Relyea et al. 2005). Larval amphibians were more susceptible in some studies 

(Relyea 2005b), but less so in other studies (Thompson et al. 2004). Glyphosate has not been tested on a wide 

range of amphibians, nor does EPA require the testing of surfactants. Proprietary labels do not always identify 

the surfactants used. Pre-project clearance evaluations for Special Status or Survey and Manage amphibians will 

help project planners choose appropriate weed treatments that have lower chance of adverse effects where these 

amphibians are likely to occur. In any event, a PEIS Mitigation Measure specifies avoiding using glyphosate 

formulations containing POEA, or seeking the use of formulations with the least amount of POEA, to reduce risks 

to amphibians (Appendix 2).

Picloram: Studies on birds, bees, and snails generally support picloram as relatively nontoxic to terrestrial 

animals. The few field studies indicated no change to mammal or avian diversity following picloram treatment. 

Variations in different exposure assessments have little impact to risk through ingestion, grooming or direct 

contact. Maximum rates have higher risk to mammals due to contaminated grass or insects. No information was 

found in the literature about picloram’s effect on reptiles (SERA 2003b).

Bromacil is an herbicide often used where maintenance of bare ground is desired. It poses a low toxicity hazard 

to terrestrial mammals, birds, and honeybees. It poses zero to low toxicity risk to mammals that ingest treated 

vegetation over time under plausible treatment scenarios, assuming they remain in the treatment area, and 

alternate food is unavailable. BLM’s application scenario reduces the risks of herbivore ingestion. There is 

practically no risk to invertebrates (ENSR 2005b).

Chlorsulfuron is an ALS-inhibitor; a group of herbicides that has the lowest risk to all groups of wildlife of 

the herbicides evaluated. All likely application scenarios are below the LOCs for wildlife groups under tested 

scenarios, even under spill or off-site drift scenarios. It is unlikely to cause any adverse effect on aquatic animals 

(Table 3-14). No studies on amphibians or reptiles were found (SERA 2004a).

Clopyralid is useful in treating starthistle, thistles, and knapweeds, which are noted as damaging to wildlife 

habitat. Clopyralid is unlikely to pose risk to terrestrial mammals. All of the estimated mammalian acute 

exposures are below the acute NOEL; mammalian chronic exposures are below the chronic NOEL. It is 

relatively “harmless” to earthworms (Dow AgroSciences 1998) and 14 of 17 insect parasites and predatory 

mites (Hassan et al. 1994 cited in SERA 2004b). There was no mortality to bees at relatively high doses. Four 

of 18 direct spray scenarios resulted in exposure levels below the estimated NOEL. Large and small birds 

have some risk of ingestion of contaminated food but hazard quotients are below the level of concern for all 

exposure scenarios. No studies on amphibians/reptiles were found. Clopyralid is one of the herbicides with 

lower toxic risks (SERA 2004b).
249

Diflufenzopyr + dicamba: Diflufenzopyr has slightly more toxic impacts to wildlife than dicamba based on 

evaluations in the Ecological Risk Assessment. The mixture has a moderate residual effect that could affect 

insects and mammals through ingestion but insect lethal effects are unlikely. It is practically non-toxic to aquatic 

invertebrates and has low toxicity to honeybees. Risk Quotients for terrestrial wildlife were all below the most 

conservative LOC of 0.1 (acute endangered species), indicating that accidental direct spray impacts are not likely 

to pose a risk to terrestrial animals. The mixture is practically non-toxic to birds, but there are some concerns for 

ingestion of contaminated thistle or knapweed manifesting in reproductive effects at high application rates. There are 

chronic and acute ingestion concerns for mammals as well (Table 3-14). Aquatic invertebrates are more susceptible 

to dicamba than fish. One study on dicamba indicates it is practically non-toxic to amphibians (ENSR 2005d, i).

Diquat is approved for aquatic use and is one of the more toxic herbicides evaluated in this EIS. It is moderately 

toxic to mammals through dermal contact and ingestion. The risks are greater for large mammals and large avian 

herbivores compared to smaller animals and birds, particularly with maximum application rates (Table 3-14). 

There are high risks to aquatic species sprayed with diquat. There are moderate to high risks identified for aquatic 

invertebrates at typical and maximum rates, and low toxicity to terrestrial invertebrates. Diquat is one of two 

herbicides evaluated in this EIS with high categories at both typical and maximum rates for Special Status species, 

partly related to aquatic exposure scenarios (ENSR 2005e).

Diuron is approved for ditch banks, but will not be used in riparian areas. It has a low to moderate tendency 

to bio-accumulate (Extoxnet 1996a). It has been rated as a surface water and groundwater contaminant (Water 

Resources section in this chapter). Acute direct spray risks on food were low for most mammal and bird 

scenarios, but exceeded the LOC for all scenarios at the maximum rate. Some chronic scenarios presented a high 

risk. Diuron has low to moderate risks to pollinators at typical and maximum rates respectively, and moderate 

to high risk for aquatic invertebrates. Diuron was listed as a risk under most direct spray and ingestion of 

contaminated food scenarios (ENSR 2005f).

Fluridone is used for submerged weeds that threaten aquatic wildlife such as watermilfoils. It has a low tendency 

to bioaccumulate (in fish). Fluridone exhibits low toxicity to most terrestrial mammals and small mammals may 

be more susceptible than large. Acute oral exposure of fluridone is practically non-toxic to birds and practically 

non-toxic to honeybees. Fluridone is one of the aquatic herbicides with the highest risk factors; however, at 

typical rate it is less toxic to fish and aquatic organisms than diquat, and has very low risk to other wildlife 

forms (Table 3-14). Application timing could avoid most susceptible (water-associated) stages of amphibian 

development, if this information is available for resident herptiles at the treatment site (ENSR 2005g).

Hexazinone: The commercial formulas are less toxic than hexazinone by itself and the liquid form is more toxic 

than granular. For granular formulations, none of the hazard quotients for mammals exceed a level of concern 

even at the highest application rate. For liquid formulations of hexazinone, hazard quotients exceed the level 

of concern at all application rates and all of the scenarios involving residue rates for contaminated vegetation or 

insects (Fletcher et al. 1994). Hexazinone and its degradates are persistent and highly mobile and hexazinone 

has been identified as a groundwater contaminate in some states. Bullfrogs were slightly more susceptible to 

behavioral change (diminished response to prodding) than leopard frogs over a 9-day study but amphibian studies 

were not adequate to determine the LD50. Hexazinone poses zero to moderate risk to mammals for ingestion under 

both acute and chronic scenarios (Table 3-15). Birds are more tolerant than mammals (SERA 2005c).

Imazapic is an ALS-inhibitor that rapidly metabolizes and does not bioaccumulate. It is effective against 

medusahead, leafy spurge, and cheatgrass, which adversely affect wildlife habitat. Imazapic is not highly toxic 

to most terrestrial animals. Mammals are more susceptible during pregnancy and larger mammals are more 

susceptible than small mammals. Imazapic has low toxicity to honeybees. No adverse short-term exposure risks 

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to birds were noted for imazapic, but some chronic growth reduction was noted. None of the risk categories for 

susceptible or non-susceptible shows any ratings that exceed the LOC. Imazapic is one of the lowest toxic risks to 

wildlife of herbicides evaluated in this EIS along with other ALS-Inhibitors (SERA 2004c).

Imazapyr is approved for aquatic use and is an ALS-inhibitor. There was no bioconcentration in aquatic Daphnia 

and toxicity is apparently low. There is a lack of information on dose levels that demonstrate harm to mammals, 

amphibians, or birds. Effects of field studies (Brookes et al. 1995) suggest observed changes to birds and 

mammals following treatment are habitat related, and not due to toxic effects. Imazapyr is one of the least toxic 

aquatic herbicides evaluated (except for accidental spill for susceptible fish). Imazapyr is only slightly more toxic 

than the other ALS-inhibitors, all of which are the least toxic of any of the herbicides evaluated (SERA 2004d).

Metsulfuron methyl is an ALS-inhibitor that does not appear to bioaccumulate. Metsulfuron methyl can be 

effective for invasive weeds that are unsusceptible to other herbicides. None of the acute or chronic exposure 

scenarios exceeded the LOC at the typical rate, and few exceeded LOC at maximum rate. Metsulfuron methyl 

has very low toxicity to birds for direct spray and consumption; no mortality of acute spray on honeybees; and, 

aquatic invertebrates do not appear to be susceptible. One study on Rove beetle indicated reduced egg hatching. 

Daphnia are relatively tolerant. Like other ALS-inhibitors, it is one of the least toxic of herbicides evaluated 

(SERA 2004e).

Sulfometuron methyl is an ALS-inhibitor. Sulfometuron methyl could be used to control weeds in riparian areas 

when no water exposure is likely. It is highly toxic to aquatic plants. The Ecological Risk Assessments indicated 

no risks to aquatic invertebrates from any scenario. All scenarios indicate no rating that exceeded the LOC, 

although it may be moderately toxic to amphibians. Sulfometuron methyl has the lowest risk to all groups of 

wildlife of the herbicides evaluated (with other ALS-inhibitors). Site-specific evaluations prior to treatment could 

reduce potential risks to amphibians possibly occurring in riparian treatment areas (SERA 2004f). Sulfometuron 

methyl can cause malformations in amphibians (SERA 2004f), but whether the malformations are caused by 

endocrine disruption, cellular toxicity, or other pathways has not been reported.

Tebuthiuron: Direct spray of tebuthiuron at the typical rate is not likely to pose risks to small mammals, although 

there are some risks to birds at typical and maximum rates—primarily due to ingestion of contaminated food. It 

has low acute toxicity to insects and direct spray is not a concern to aquatic invertebrates. Off-site drift issues 

related to tebuthiuron are unlikely to affect aquatic wildlife, but accidental spray exceeded LOC for aquatic invert 

risk in ponds or streams. At low rates, tebuthiuron can help restore ecological mosaics in sagebrush ecosystems 

important to sage grouse and pygmy rabbits (Crawford et al. 2004, ENSR 2005k).

Triclopyr is approved for aquatic use and can be used on saltcedar, watermilfoil, and purple loosestrife, all species 

known to adversely affect wildlife habitat. Triclopyr, as triethylamine (TEA) salt and butoxyethyl ester (BEE), is 

covered in the Risk Assessments. Some formulations of the TEA salt of triclopyr have been labeled for aquatic 

weed control. Triclopyr TEA is less toxic to wildlife than triclopyr BEE. The major metabolite of triclopyr, 

3,5,6-trichloro-2-pyridinol (TCP) has about the same toxicity as triclopyr. At the upper range of exposures, 

hazard quotients for triclopyr exceed the LOC for large mammals, but average hazard quotients do not exceed 

the LOC for any exposure scenario. Triclopyr acid is practically non-toxic to slightly toxic to birds and triclopyr 

TEA and triclopyr BEE are practically non-toxic to birds. Consumption of treated vegetation (and insects) is the 

greatest concern for birds or mammals. Of aquatic-approved herbicides evaluated in this EIS, triclopyr risk is 

about average. Using less toxic formulas reduces risk (SERA 2003c).
251

Habitat Change Resulting from Invasive Plants

The International Union for the Conservation of Nature (IUCN) notes that a significant proportion of species now 

considered extinct were driven to extinction by invasive species, and generally ranks invasive species as one of 

the top ten threats to currently threatened species (IUCN 2008). 

Loss and degradation of habitat is a major contributor to native wildlife population declines (PIF 2002, Noss et 

al. 1995). Native bird diversity has been positively correlated with native plant diversity (by volume), but had 

no or negative correlation with exotic vegetation (Mills et al. 1989, Germaine et al. 1998). Wilcove et al. (1998) 

documented that invasive species have adversely affected approximately 46 percent of the plants and animals 

Federally Listed as endangered species (USDA 2003b). Severe weed infestations can cause declines in native 

diversity, habitat quality, and ecosystem function (Asher 2000, Lacey and Olsen 1991). Russian knapweed 

infestations resulted in severe reductions of kangaroo rat and ground squirrel populations in Wyoming (Johnson et 

al. 1994). Spotted knapweed invasion was found to reduce available elk winter forage 50 to 90 percent (Duncan 

1997). Herbivores avoided leafy spurge (Trammell and Butler 1995). The thorns and seedpods of many invasive 

plants can kill or injure wildlife (Archer 2001). Bats and hummingbirds have been killed by entrapment on 

burdock seedheads (burrs) (Raloff 1998).

Weeds can particularly devastate riparian wildlife habitat. Thompson et al. (1987) found that muskrats and longbilled marsh wrens leave marshes infested by purple loosestrife. Mammal, reptile, and amphibian populations 

were reduced when habitat was invaded by weeds (Duncan et al. 2004). Saltcedar reduced habitat for some birds, 

reptiles and mammals (Zavaleta 2000) but more human-communal species such as crows, magpies and mourning 

doves were more common in saltcedar sites (Harmon et al. 2006). Non-native weeds can choke out native species 

and fill-in open water areas to adversely impact amphibians, which prefer a proportion of open water in their 

habitat (Brotherson and Field, 1987, Dudley 2000, Horton 1977). Haycock (1999) reported that Oregon spotted 

frog populations are threatened by the invasion of reed canary grass that reduces open-water habitat in their 

shallow marsh habitats.

Some wildlife apparently benefit from, or at least tolerate, invasive plants, but invasive plants seldom provide 

wildlife the same food and cover quality as native species. American goldfinch and red-winged blackbird 

utilize purple loosestrife (Kiviat 1996, Thompson et al. 1987); non-native chukar will utilize cheatgrass early 

in the spring (Csuti et al. 1997), and; elk, deer and rodents eat rosettes and seed heads of spotted knapweed 

and dandelion. Forage quality is reduced in weedy habitats (Bedunah and Carpenter 1989, Rice et al. 1997b, 

Trammell and Butler 1995), and functional cover for many species of wildlife is reduced. The few uses that an 

invasive plant may provide do not outweigh the adverse impacts to an entire ecosystem (Zavaleta 2000).

Recruitment and survival of juvenile sage grouse (Special Status) is considered to be positively correlated to the 

historic amount, distribution and pattern of sagebrush habitat (Connelly et al. 2004), which is negatively affected 

by the increase in invasive annual grasses (Hagen 2005, Wisdom et al. 2005) and the increase in western juniper 

expansion (Hagen 2005, Wisdom et al. 2005, Suring et al. 2005). The increase in western juniper increases 

perches for predatory birds, which increases predation (lethal population impacts) on sage grouse. Annual 

invasive grasses increase fire frequency beyond the historic fire interval and often results in an annual grass/fire 

system that prevents sagebrush reestablishment. This changes disturbance patterns, which lowers the fitness of 

most of the native sagebrush wildlife species such as sage grouse, pygmy rabbits, and Brewer’s sparrows (all 

Special Status), and increases chronic lethal impacts on those species.

Western pond turtles (Special Status) require bare, sandy soil near water to dig nests in which to deposit 

eggs. The eggs need the thermo-regulation of the non-vegetated soil to mature. Purple loosestrife, Himalayan 

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blackberry, and other noxious weeds can quickly overtake bare soil in riparian areas, changing the solar regulation 

processes. Turtles are forced to lay eggs that don’t mature, move further from riparian areas (increasing 

predation), or fail to nest at all (Hays et al. 1999).

Leafy spurge invades grasslands and changes the vegetative structure. Changes are beneficial for western 

meadowlarks but adverse for savannah and grasshopper sparrows (Scheiman et al. 2003).

Some invasive plants (such as knapweed) contain chemical compounds that make the plant unpalatable to 

grazing animals. Chemical compounds in these invasive plants disrupt microbial activity in the rumen, or cause 

discomfort after being ingested, resulting in a reduced or avoided consumption of the invasive plant (Olson 

1999). Invasive plants can act as a population sink by attracting a species and then exposing them to increased 

mortality or failed reproduction (Chew 1981). For example, Schmidt and Whelan (1999) reported that native 

birds increased their use of exotic honeysuckle and buckbrush shrubs over native trees, even though nests built in 

the exotic shrubs experienced significantly higher mortality rates.

Maintenance or improvement of conditions and processes found in healthy native ecosystems would have 

beneficial long-term effects to the native wildlife that are associated with that ecosystem, particularly rare species. 

Alternatives that protect or restore the greatest number of acres of native vegetation (see Table 4-4 in the Noxious 

Weeds and Other Invasive Plants section) would have correspondingly greater benefits to wildlife populations, 

particularly when Standard Operating Procedures and PEIS Mitigation Measures reduce or avoid short-term 

adverse effects. One of the two objectives of the BLM’s Special Status Species policy is “to initiate proactive 

conservation measures that reduce or eliminate threats to Bureau sensitive species to minimize the likelihood of 

and need for listing of these species under the ESA” (USDI 2008d).

Habitat Change Resulting from Vegetation Treatments

Native wildlife may use invasive plants but they are seldom dependent upon them; they would typically fare better 

with native plants. Invasive plants such as blackberries are still more detrimental to native wildlife habitat than the 

benefits they provide because they displace more valuable native fruiting shrubs. Some of the species benefitting 

from invasive plants are actually exotics such as starlings. There is potential for localized adverse effects to 

wildlife habitat from weed control treatments resulting from the collateral damage to native species. The potential 

for such habitat changes to adversely affect species would depend upon the vegetation species affected, the 

percent of native vegetation within the home range/population of a species that is affected, the importance of that 

vegetation to the resident wildlife, and the availability of unaffected vegetation in the treatment area.

Few broad-scale treatments of native vegetation are anticipated to be conducted under any of the alternatives 

unless they are specifically designed to benefit wildlife habitat (Chapter 3, Assumptions about Herbicide 

Treatments). Invasive plant treatments are generally directed only at noxious weeds and other invasive plants, 

either by treating only the invasive plant or by using a selective herbicide. The objective of those treatments is to 

remove weeds and restore native (or other non-invasive) vegetation. Treatments are designed to reduce damage to 

native vegetation and reduce unnecessary site disturbance that favors reinvasion by invasive plants.

Most weed treatments are spot treatments directed at specific plants. Collateral damage to native habitats is 

insignificant or limited to the immediate area. The BLM uses non-herbicide methods with care, by design, or uses 

the smallest amount of herbicide that will kill the weed, so that the risk of non-target mortality is low. The Native 

and Other Non-Invasive Vegetation section in this Chapter notes that the risk to non-target plants from herbicide 

treatments is less under the action alternatives than under the No Action Alternative (Alternative 2). Some 

habitats are so infested with weeds they offer little suitable habitat for native wildlife. It is unlikely that sites too 
253

heavily infested with weeds for spot treatments but still retaining enough native vegetation to serve as important 

habitat for native wildlife species, would be treated unless there are over-riding objectives, such as restoration of 

Special Status species’ habitat or special use areas.

Disturbance to Wildlife in or Near the Treatment Areas

Both herbicide and non-herbicide treatments have the potential to disturb wildlife. Disturbance may disrupt 

normal behavior to the extent survival of adults is impaired or reproduction compromised depending on the 

intensity of disturbance, extent of habitat affected, duration of the activity, and whether the activity occurs during 

a vulnerable time such as when the animal is restricted to a nest, breeding area, or winter range. If an animal is 

frightened from its habitat, displacement away from habitat can be as short as a few hours or as much as several 

days. Disturbance can be most significant for rare species such as the pygmy rabbit, because effects to individuals 

can adversely affect already reduced populations in fragmented habitat.

Vehicle Use: Up to 33 percent of herbicide application is anticipated from vehicles (ATV/Trucks) off roads 

(Chapter 3), and 20 percent is predicted to occur from existing roads. OHVs are used almost exclusively to carry 

mix tanks for individuals on foot to spot-spray target weeds. The vehicles travel slowly to avoid accidents and 

spills, reducing the potential for adverse effects when compared to other types of vehicle effects. Equipment (e.g., 

mowers) and vehicles can also hit or injure ground nesting birds, amphibians, reptiles, invertebrates and small 

mammals and their nests, particularly sessile mollusks or wildlife like grouse that “hide and cower.” Vehicles 

can break down pygmy rabbit “tunnels” through the sagebrush making the rabbits more vulnerable to predation. 

Raptors and corvids have learned to follow human pathways and prey on ground nesting birds, causing increased 

mortality. OHVs or small crews of individuals doing spot-treatments would likely have negligible disturbance 

impacts to most common wildlife. Clearances for Federally Listed and other Special Status species would 

identify the important habitats of rare species so potential disturbance/disruption to those areas could be avoided, 

at least during the most vulnerable periods of the year.

Manual/Mechanical/mowing/planting treatments may involve chainsaws and motorized equipment that have the 

potential to disturb or disrupt species during vulnerable life stages. Manual treatments are more likely to require 

repeated treatments (and cause increased disturbance risks). Mowing/chaining, plowing have disruption potential 

due to noise, and also could kill or injure sessile or slow-moving wildlife such as mollusks, worms or non-flying 

insects, newly-born young, or immobile life forms such as eggs that are in the direct path of ground-disturbing 

machinery. The extent of direct injury is dependent on the duration of the disturbance, the footprint of the grounddisturbing/habitat changing treatment, time of year of the activity, the density and vulnerability of native wildlife 

in the treatment area, and acres affected.

Directed livestock has some potential for disturbance because the activity is intensive and highly focused. 

Directed livestock grazing would likely occur in areas where weed density has already severely degraded native 

wildlife habitat. Disturbance to native wildlife would be insignificant and short-term.

Biological controls would have negligible disturbance effects occurring when biological agents are released, and 

monitored.

Prescribed Fire for Weed Control: Most native wildlife populations have adaptive mechanisms that facilitate 

their resilience to natural disturbances. Russell et al. (1999) summarized the literature on herptile (and other 

wildlife) responses to fire and noted that most wildlife can avoid harm by leaving the treatment area or by 

burrowing. Although there is potential for some harm or mortality during vulnerable periods (snake skinshedding was mentioned), they cite Means and Campbell (1981) “it is illogical that animals associated with 

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fire vegetation are not themselves at least behaviorally adapted to resist mortality by fire” and cite Lyon et al. 

(1978), Wood (1981): “high levels of fire-induced mortality also appear to be uncommon in many species of 

birds and mammals.” Prescribed fire, which often occurs earlier in the season or during wetter times of the year 

than wildfire, might occur during breeding seasons and thus might have more potential to kill or injure immobile 

species, eggs, and young. 

Herbicide application has disturbance potential. Foot traffic from people using backpack sprayers or daubing 

herbicide is similar to foot traffic disturbance from manual methods (hand pulling). Crews work slowly and 

wildlife have time to move out of the way (USDA 2005a). The disturbance effects of power sprayers and 

motorized equipment could be considered similar to that of chainsaws, although crews might move through an 

area more quickly. The disturbance from boom-sprayers is similar to vehicle and OHV effects, but boom sprays 

would generally be used only along roads and other rights-of-way. Aerial applications can cover large areas and 

be intense, but disturbance at any one area is of short duration. Wildlife varies in their sensitivity to over-flight 

disturbance, but most response would be indirect and related to wildlife leaving cover or food for various periods.

Effects by Alternative

Reference Analysis – No Herbicide Use

Disturbance Effects: Not using herbicides would result in a net decrease of 3,400 acres of habitat treated annually 

compared to the No Action Alternative (Alternative 2), so the potential of short-term impacts to wildlife in the 

treatment area would decrease. No herbicide impacts would result to wildlife from BLM activities under this 

alternative. Compared to the No Action Alternative, the 1,600-acre increase in mechanical treatments, particularly 

those with ground-disturbing potential such as plowing/disking or chaining, would have greater disturbance 

potential to native wildlife in the treatment area than any of the alternatives. Some sites would be disturbed 

several times to meet the same weed treatments result, since the effectiveness of treatments without herbicides is 

predicted to average 30 percent.

Invasive Plant Effects: Because non-herbicide methods are not particularly effective at controlling about 2/3 of the 

noxious weeds in Oregon (Appendix 7: Table A7-1), a no-herbicide strategy would reduce opportunities to control 

several weed groups that adversely affect wildlife habitat. These groups include the annual grasses which have 

severely affected the sagebrush ecosystem (sage grouse, pygmy rabbits), Oak Woodlands (Columbia white tail 

deer, other ungulates, upland game birds), and the Siskiyou Biome (Mardon skipper). This strategy would also 

preclude the use of pre-emergent herbicides that can be effective in restoring wet meadow habitats, where soil or 

ground-disturbing effects would preclude plowing/disking, or where such post-treatment herbicide treatments are 

needed after mechanical treatments to prevent new (or different) weed invasion. Limiting the tools available for 

restoration activities could result in important wildlife habitat being untreated because successful native habitat 

restoration would not be assured.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Herbicide and Non-Herbicide Treatment Effects: The four herbicides available under this alternative include 

two of the six herbicides proposed in this EIS that have high risk categories to wildlife (including aquatic 

invertebrates): 2,4-D and glyphosate. Glyphosate can be moderately toxic to amphibians, most likely due to 

the surfactant POEA. The current 12 percent rate of spread increases the number of acres that may be exposed 

to increased disturbance resulting from treatments and a higher chance of adverse exposure to herbicides from 

treatments. The use of broad-spectrum herbicides like glyphosate increases the risk of damage to non-target 

vegetation important to wildlife. Glyphosate and 2,4-D are the only herbicides under Alternative 2 authorized for 
255

aquatic weeds, and each has the possibility of adverse impacts to amphibians. Glyphosate may be a poor choice 

for aquatic weeds because it dilutes rapidly in water, and can adhere to soil particles at label rates before it reaches 

levels toxic to target plants. 

Invasive Plant Effects: The inability to control invasive plants that are not yet listed as noxious weeds increases 

the chance that new invasive plants might become well established prior to being controlled; thus, habitats are 

more difficult to protect. In addition, none of the herbicides under Alternative 2 are selective against annual 

grasses, so medusahead and cheatgrass would continue to degrade sage grouse and other habitats. Approximately 

1/3 of the BLM lands in Oregon are projected to be infested with noxious weeds in 15 years, with a corresponding 

decrease in their value to wildlife. Restoration and recovery for rare species could be deterred when invasive 

plants invade their habitat.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Herbicide Effects: The wider choice of herbicides available under this alternative would increase the likelihood 

that a more target-specific herbicide could be used to reduce collateral damage in or near the treatment area. 

Alternative 3 includes the use of three herbicides that had risk levels below the Level of Concern (LOC) for all 

evaluated wildlife under all scenarios: chlorsulfuron, imazapic and sulfometuron methyl.

Alternative 3 adds three more herbicides approved for use in aquatic habitats, facilitating the selection of 

herbicides with less toxic effects to aquatic wildlife. The likelihood of having an herbicide that can be used to 

treat invasive plants within habitats occupied by rare wildlife species would be substantially increased under this 

alternative. The addition of imazapyr as an aquatic herbicide allows use of an herbicide with zero risk to aquatic 

invertebrates at typical application levels (Table 3-15). It would provide an alternative to glyphosate where there 

may be amphibian concerns.

Invasive Plant Effects: More habitat would be protected under this alternative and more weeds could be curtailed 

before they become established, compared to the No Action Alternative (Alternative 2); noxious weeds are 

projected to infest 1.9 million fewer acres in 15 years. Alternative 3 also would extend herbicide treatments to 

invasive plants not yet listed as noxious weeds. Sagebrush Steppe Biome wildlife would benefit from imazapic to 

control cheatgrass and medusahead; none of the treatment measures or herbicides available in Alternative 2 are as 

effective at controlling these invasive annual grasses. Tebuthiuron could help restore essential sagebrush mosaic 

seral patterns. The additional herbicides expand integrated vegetation management options, such as combining 

herbicides following burns to reduce the chance of target weeds from re-establishing, or other weeds from 

invading the burn site.

Disturbance Effects: Additional herbicides provide managers with more flexibility to tailor treatments to benefit 

wildlife by allowing use of herbicides with wider seasonal windows (making avoidance of susceptible wildlife 

periods more feasible), and facilitating greater opportunities to implement integrated vegetation management 

strategies that combine herbicides and non-herbicide treatments to more specifically meet ecological goals. 

Herbicides have lower ground-disturbing effects, so there would be less chance of disturbance to microsites for 

mollusks, reptiles, birds, and invertebrates.

Sudden Oak Death: Treating Sudden Oak Death-infested native habitat with herbicides could reduce, but not 

avoid, the adverse effects to wildlife caused by treating Sudden Oak Death under Alternative 2. Sudden Oak 

Death occurs in late seral coniferous forests in western Oregon that is also essential habitat for the Federally listed 

marbled murrelet and northern spotted owl. The non-herbicide treatment for Sudden Oak Death includes cutting 

of infested plants and susceptible plant species, and repeated burning (USDA, USDI 2008). The intensive and 

repeated treatment for Sudden Oak Death under non-herbicide methods has adverse disturbance effects on both 

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of these species. The loss of vegetation and habitat inherent to Sudden Oak Death treatment cannot be avoided, 

but repeated mechanical and permanent ground disturbance related to treatment of Sudden Oak Death areas could 

be reduced with the use of herbicides, and the higher likelihood of control will benefit wildlife. Many of the host 

species affected by Sudden Oak Death are also important for wildlife forage and structure. See the Pests and 

Diseases section for more details about Sudden Oak Death.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

Effects include all those described for Alternative 3, in addition to the following:

Effects of Herbicides: Many of the Conservation Strategies identify weeds and habitat degradation as a factor 

contributing to the rare status of the species. The ability to use herbicides for certain habitat improvements would 

increase the number of acres treated for wildlife recovery. For example, low-dose application of tebuthiuron 

can be an effective herbicide to help restore sagebrush mosaics in sage grouse restoration (Olson and Whitson 

2002, Johnson et al. 1996). The use of herbicides as a restoration tool for wildlife habitat can reduce or avoid the 

adverse effects associated with fire or mechanical methods.

Alternative 4 would also make herbicides available to treat rights-of-way, administrative sites, and recreation 

sites. Treating native and other non-invasive vegetation on these sites would increase the risk of herbicides on 

plants being ingested by wildlife. Diuron, bromacil, and tebuthiuron become available under this alternative, 

although diuron and bromacil are normally applied to soil or very low growing vegetation where the maintenance 

of bare ground is the objective. Diuron has a higher risk than some of the herbicides available under Alternatives 

2 and 3, primarily for ingestion situations for mammals, but it also has lower risk for birds at the typical rate than 

some of those same herbicides. Bromacil is one of the herbicides with lowest risk to invertebrates, and is one of 

the least impactful of herbicides that have risks for Special Status species. Ingestion for most wildlife is unlikely 

because bromacil will be used as a pre-emergent herbicide. Tebuthiuron has no more than low category for 

typical application rates in all exposure scenarios including those to Special Status species. Some animals, like 

deer, will seek out openings, such as rights-of-way because they provide lower growing succulent plants. Bears 

and other large mammals often use road or power line rights-of-way for travel because the reduced vegetation 

is easier to navigate, and raptors will often hunt along the openings. Exposure through ingestion of herbicidecontaminated forage is increased if diuron is applied to forage vegetation in these areas.

Effects of Invasive Plants: Wildlife habitat would benefit from the reduced spread of noxious weeds and other 

invasive plants; noxious weeds are projected to infest 300,000 fewer acres in 15 years under Alternative 4 than 

under Alternative 3.

Effects of Treatment: Herbicides are projected to be used on 9,300 acres to meet native and other non-invasive 

vegetation control objectives in and adjacent to rights-of-way and other developments. These objectives are 

currently being met with other non-herbicide methods. Roadsides would most likely be sprayed with low boom 

nozzles fixed to vehicles on the road; power line and other linear rights-of-way could be treated similarly using 

existing access roads, and in some instances east of the Cascades, aerial application could be used. Disturbance 

effects to wildlife are low at many of these sites because the development often displaces animals that are 

susceptible to noise and activity away from these areas, limiting their exposure, or they become habituated to it. 

In any event, herbicide application activities would be no more disturbing than current non-herbicide treatments.

Continued maintenance of early seral vegetation under power lines can be beneficial to some species. A 

symposium of papers evaluating rights-of-way across the United States and Canada included several studies 

where rare species used or even benefitted from right-of-way habitat and vegetative treatments (including 
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herbicide treatments) on those areas (Goodrich-Mahoney et al. 2000). Wildlife could be adversely affected by 

herbicides and/or habitat change when sites are treated, but it is the maintenance of current conditions that keeps 

the early seral habitat from being converted to less favorable conditions due to natural succession.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Effects include all those described for Alternative 4 (Proposed Action), in addition to the following.

Effects of Herbicides: The moderate residual effect of diflufenzopyr + dicamba could affect insects and mammals 

in treatment areas because of proposed use in forest and rangeland situations. Diquat is one of the most hazardous 

herbicides for wildlife proposed in any of the alternatives, but use is limited to aquatic applications where it could 

be used to control giant salvinia if it were to enter Oregon or as a back-up for one of the other aquatic herbicides if 

they were to become ineffective. The effects on desirable aquatic wildlife would be evaluated at the site-specific 

level. Additional site-specific mitigation could be applied, where appropriate, to reduce effects. In the case of 

both herbicides, the proposed use is low.

Effects of Treatments: Approximately 4,800 additional acres would be treated under Alternative 5, and these could 

be for a full range of vegetation management objectives except livestock forage and timber production. Most of 

this increase is expected to go to additional wildlife habitat improvement treatments not included in Alternative 

4 (Proposed Action). Native vegetation such as rabbitbrush and western juniper could be treated in this scenario, 

for example, to help restore healthier native sagebrush habitats.

Alternative 5 has the greatest opportunity for wildlife habitat improvement treatments, and potentially the greatest 

positive effects to wildlife. Re-establishing ecosystems to be sustainable under fire disturbance could have 

long-term benefits to the wildlife populations in those ecosystems. Wildlife habitat improvement treatments 

that restore complex mosaic shrub/forb/bunchgrass communities would generally be beneficial to sagebrushdependent wildlife (Crawford et al. 2004). Any adverse effects would be considered at the site-specific level. 

There could be potential short-term impacts from the treatment of native shrubs such as rabbitbrush, which can 

be locally important to pollinators (Stephen, B. pers. comm.), or to herbivores where in the late season more 

palatable vegetation is unavailable (Clements and Young 1997). Treatments designed to reduce fire risk may have 

short-term adverse impacts to wildlife. Vegetation changes that are sufficient to reduce fire risks can be more 

extensive and intensive than weed treatments, and thereby have a greater chance of reducing native vegetation 

important to local wildlife for the short-term.

Cumulative Effects

Native wildlife in Oregon has been influenced by dozens of stressors since the onset of European settlement. 

Habitat continues to be lost to natural and anthropogenic disturbances, resulting in highly fragmented habitat for 

most wildlife species and population levels decreased from historic levels. Wildlife that prefer or tolerate human 

activities and habitat changes such as coyotes and ravens have increased, often outcompeting less adaptable 

wildlife. Invasive plants and animals reduce native wildlife survival and contribute to unhealthy ecological 

systems, unbalanced communities, and decreased connectivity.

Use of herbicides, fungicides, fertilizers, and insecticides contribute to the landscape levels of chemicals in the 

environment (Table 4-1). Some of the more toxic (generally non-BLM) chemicals can accumulate in wildlife 

over the long-term (Belden et al. 2006). Several other herbicides such as alachlor, diquat, glyphosate, picloram, 

and 2,4-D also have been detected in surface and ground water, and the EPA has assigned MCLs to all of them 

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(Stevenson et al. 1997). Field studies of herbicide effects are few and some unforeseen risks may exist (Blus 

and Henny 1997). There is a chance of additive chemical reactions in downstream waterways from combining 

off-site herbicides from BLM projects with runoff from more dangerous insecticides used in intermingled private 

agricultural lands. The BLM reduces this risk as much as possible by using targeted application methods, 

herbicides with low persistence and low toxicity, and establishing buffers around susceptible areas.

BLM lands make up 25 percent of the lands in Oregon, a high percentage of the habitat for native wildlife 

remaining in Oregon, and 70 percent of the remaining Oregon sage grouse habitat (Hagen 2005). The addition of 

more tools to control weeds under any of the action alternatives would improve opportunities to more effectively 

work cooperatively across multiple ownerships. Neighbors may be more inclined to treat weeds adjacent to BLM 

if the BLM lands were also treated and were not a source population for reintroduction of noxious weeds. Weed 

treatment partnerships would be more effective within logical control areas.

The Proposed Action (Alternative 4) is projected to result in 2.2 million fewer acres of noxious weeds over the 

No Action Alternative (Alternative 2). When used in conformance with the Standard Operating Procedures and 

PEIS Mitigation Measures, and after site-specific analysis, the herbicide risks to wildlife appear to be less than 

the documented effects of additional infestations of invasive plants. Although use of some of these herbicides 

may pose some risk to individuals within a wildlife population in some cases, the reduction or slowing of invasive 

plants at this magnitude will benefit wildlife populations and vegetation community health on a landscape scale.

Livestock

Affected Environment

Approximately 14 million acres of public lands in Oregon are open to livestock grazing, with use levels 

established in land use or resource management plans and administered through the issuance of grazing permits/

leases. The majority of the grazing permits issued by the BLM involve grazing by cattle, with fewer and smaller 

grazing permits for other kinds of livestock (primarily sheep and horses).

The BLM conducts grazing management practices through BLM Manual Handbook H-4120-1 (Grazing 

Management; USDI 1984a). Management of livestock grazing is authorized and enforced through both permits 

and leases. The grazing permit establishes the allotment(s) to be used, the total amount of use, the number and 

kind of livestock, and the season of use. Term grazing permits/leases may also contain terms and conditions as 

appropriate to achieve management and resource condition objectives. Allotment management plans further 

outline how livestock grazing is to be managed to meet multiple-use, sustained yield, and other needs and 

objectives, as identified in the resource management plans.

Rangeland Health Standards and Guidelines for Livestock Grazing Management for Oregon and Washington 

were approved by the Secretary of the Interior in August 1997 (USDI 1997). The standards are expressions of the 

physical and biological condition or degree of function necessary to sustain rangeland ecosystems. The standards, 

designed to comply with 43 C.F.R. 4180, direct management toward the maintenance and restoration of physical 

function and biological health of rangeland ecosystems. The five standards are:

1) watersheds are in or making significant progress towards properly functioning physical condition in 

uplands areas;

2) watersheds are in or making significant progress towards properly functioning physical condition in 

wetland-riparian areas;
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3) ecological processes including the hydrologic cycle, nutrient cycle, and energy flow are maintained;

4) water quality complies with State water quality standards; and,

5) significant progress is being made toward restoring or maintaining habitats for all Special Status 

species.

Reviews of rangeland health standards are often conducted when grazing permits or leases expire, particularly 

when those permits or leases are within Clean Water Act section 303(d)-listed streams or Essential Fish Habitat 

watersheds.

Public lands provide an important source of forage for many ranches, especially during spring and summer 

months, allowing private lands to be devoted to the production of feed sources and resources to sustain operations 

the remainder of the year. Grazing on these lands helps support the agricultural component of many communities 

scattered throughout the west. As of February 2009, the total number of grazing permits/leases in Oregon was 

1,286, with 1,022,645 Animal Unit Months (AUMs) authorized (USDI 2009a). Most grazing is east of the 

Cascades. Authorized livestock grazing west of the Cascades is limited to portions of Josephine and Jackson 

Counties. The 88 grazing leases in these two counties have a composite authorized or allowable use of up 

to 15,220 animal unit months (AUM) on an estimated 329,995 acres. Actual livestock AUM use west of the 

Cascades is generally far less due to variations in individual operator preferences, seasonal availability of forage, 

and other factors. Some leases are inactive and others are planned to be phased out over time (i.e., 49,423 acres, 

2,714 AUMS, and 11 grazing leases in the Cascade Siskiyou National Monument in Josephine County).

Livestock consume annual and perennial native and introduced grass species, and seasonally utilize forbs and 

some shrubs. Healthy plant communities support current livestock grazing levels. Invasive plants reduce forage 

for livestock, degrade plant community health, and result in reduced capacity to sustain existing grazing levels. A 

combination of invasive plants and shorter fire return intervals59 can further limit forage use from year-round, to 

seasonal, or to none at all.

Some grazing permit holders are seeking, or have, organic certification. Herbicide use within these allotments 

could conflict with this objective.

Environmental Consequences

This section addresses the reasonably foreseeable effects of the alternatives on livestock grazing on BLM lands in 

Oregon. The effects of the alternatives on other ecological functions of rangelands are described in other resource 

sections in this Chapter. It is recognized that all alternatives exclude herbicide use specifically for livestock 

forage production. That means that herbicide use proposals will not, either as an objective or as an evaluation 

criterion, have a site-specific forage production purpose. Noxious weed (and pest and disease) treatments are 

driven instead by weed control objectives including stopping new weeds from getting a foothold, preventing 

existing weeds from spreading to new areas, protecting or restoring susceptible areas such as Special Status 

species’ habitats, and preventing weeds from spreading to adjacent non-BLM lands. Such treatments could occur 

in grazing areas in part because invasive plants can occur anywhere and in part because disturbed sites are favored 

by most noxious weeds and other invasive plants, and livestock can serve as a vector.

Nevertheless, noxious weed control efforts are going to affect future grazing numbers, much the same way control 

efforts will affect such things as water quality, and visual resources. Economic effects, including those resulting 

59 Reference is to the cycle of invasive annual grasses like cheatgrass, and their effect of substantially shortening natural 

fire return intervals at the expense of native (and more palatable) vegetation.

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from lost productivity on grazing lands within the State are one criterion the State uses when considering whether 

to designate non-native plants as noxious weeds. To the degree BLM noxious weed treatments contribute to 

the control and elimination of weeds the State and neighboring landowners have identified as needing control, 

Chapter 1’s Purpose number 5 of cooperatively controlling invasive plants so they do not infest or reinfest 

adjacent non-BLM lands, will be furthered.

Effects to livestock from the Proposed Action (Alternative 4) or one of the other action alternatives could result 

from direct or indirect contact with the herbicides, from inadvertent reductions in forage amount and preferred 

forage type, and from the reduction of noxious weeds and restoration of native vegetation.

Effects Common to All Alternatives

Effects of Herbicides on Livestock

The extent of direct and indirect impacts to livestock from herbicides would vary by the application method, 

herbicide used, physical features of the terrain including the presence of forage, and the weather conditions at the 

time of application. Possible adverse direct effects to individual animals include death, damage to vital organs, 

change in body weight, decreases in healthy offspring, and increased susceptibility to predation. The impacts of 

herbicide use on individual livestock would depend directly on the susceptibility of each species to the particular 

herbicides used, how the individual animal was exposed to the herbicide, and indirectly to the degree to which 

a species or individual is positively or negatively affected by changes in rangeland conditions, including forage 

quality and availability. Livestock would have a greater chance of being adversely impacted by herbicide use 

if the pasture or use area was partially or completely sprayed because they would have greater exposure to 

herbicides through direct contact with the herbicide upon application or indirect contact via dermal contact with 

vegetation or ingestion of vegetation.

When herbicide labels prohibit grazing, or risks are otherwise anticipated, exposure is typically reduced by 

the removal of livestock during vegetation treatments, scheduling treatments when livestock are not present, 

temporarily fencing the treated area, or herding the livestock away from the treatment area and shutting off 

water or using other techniques to keep them away. However, the grazing permit holder would be adversely 

affected in the short term because of the area being temporarily unavailable for grazing purposes. Additionally, 

in the short term, there could be impacts to the sale and consumption of livestock because of mandatory 

restrictions (quarantine) associated with the use of herbicides. During the interim period, the permit holder 

may incur additional costs for replacement forage and/or a loss of income. Livestock may experience greater 

impacts in systems where herbicide transport is more likely, such as areas where herbicides are aerially sprayed 

adjacent to rangeland, dry areas with high winds, or areas where rainfall is high and soils are porous; however, 

these scenarios have not been modeled. The degree of interception by vegetation, which depends on site and 

application characteristics, would also affect direct spray impacts.

The impacts of herbicide use on livestock would be site and application specific, and as such, site assessments 

would have to be performed, using available impact information, to determine an herbicide use strategy that 

would minimize impacts to livestock.

Effects of BLM-Evaluated Herbicides

According to BLM Risk Assessments, herbicide exposure scenarios of direct spray, spill, and indirect contact 

with foliage after direct spray do not pose a risk to small mammals (large mammals were not modeled, but 

have a smaller surface area to body weight ratio, so are less likely to be impacted by these scenarios than small 
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mammals; Table 3-14). Several herbicides do pose a risk to large mammalian herbivores under a scenario of 

ingestion of food items contaminated by direct spray, and these are presented below. The receptor chosen for the 

large mammalian herbivore was a 154-pound mule deer.

Bromacil does not present a risk to small mammals via direct spray or indirect contact with foliage after direct 

spray (Table 3-14; ENSR 2005b). These scenarios are very conservative because they assume 100 percent 

absorption and because small mammals have a relatively large surface area for absorption of herbicide. 

Therefore, it is unlikely that bromacil would affect larger livestock under these scenarios. Low chronic risk for 

large mammal ingestion at the typical rate, and low acute and moderate chronic risks for ingestion scenarios 

at the maximum application rate suggest direct spray of bromacil onto rangeland could pose a risk to livestock 

consuming sprayed vegetation, particularly if applied over large areas. However, bromacil is a non-selective 

herbicide that is not registered for application on rangelands or other livestock grazing areas where some 

vegetative cover is desired, suggesting that under typical use bromacil would not affect livestock. Any risk would 

come from off-site transport of bromacil to livestock grazing areas or treatment of vegetation in accessible rightsof-way. Use of bromacil in spot applications or over small areas is not likely to affect livestock. Based on label 

directions, there are no restrictions on livestock use of treated areas.

Chlorsulfuron risk quotients for mammals for all modeled scenarios were below the conservative LOC of 0.1, 

indicating that direct spray and ingestion of sprayed vegetation is not likely to pose a risk to livestock (Table 3-14; 

ENSR 2005c). Based on label directions, there are no restrictions on livestock use of treated areas.

Diflufenzopyr is not proposed for use alone. Risk quotients for terrestrial animals were all below the most 

conservative LOC of 0.1, indicating that direct spray of diflufenzopyr is not likely to pose a risk to livestock 

(Table 3-14; ENSR 2005d). Based on label directions, there are no restrictions on livestock use of treated areas.

Diquat: Low chronic risks for ingestion scenarios at typical rates, and low to moderate chronic and acute risks at 

maximum rate (Table 3-14; ENSR 2005e) suggest that livestock could be at risk from the short- and long-term 

consumption of vegetation contaminated by diquat. However, use on BLM lands would be limited to aquatic 

applications; diquat is not registered for rangelands. Thus, the likelihood of exposure of livestock to diquat is 

minimal. Livestock that feed exclusively in riparian areas where drift might be present on riparian grasses, and/

or drink water from ponds treated with diquat, are potentially at risk. However, labels require livestock to be 

removed from areas with such exposures.

Diuron: There were no acute risks but low to moderate chronic risk if food was directly sprayed at the typical 

application rate; there would be low acute risk and moderate to high chronic risk if food was sprayed at the 

maximum application rate (Table 3-14; ENSR 2005f). However, because diuron is a non-selective herbicide not 

likely to be broadcast where vegetation is desired, and not registered for use on rangelands, exposure to livestock 

would be limited. Any exposure would likely be limited to rights-of-way use, off-site drift, or surface runoff. 

Based on label directions, there are no restrictions on livestock use of treated areas.

Fluridone: Risk quotients for large terrestrial animals were below the most conservative LOC of 0.1 for all 

scenarios (Table 3-14; ENSR 2005g). These results indicate that accidental direct spray or drift of this aquatic 

herbicide would be unlikely to pose a risk to livestock.

Imazapic: Risk quotients for terrestrial animals were all below the most conservative LOC of 0.1, indicating that 

direct spray or drift of imazapic would be unlikely to pose a risk to livestock (Table 3-14; ENSR 2005h). Based 

on label directions, there are no restrictions on livestock use of treated areas.

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Dicamba + diflufenzopyr poses a low chronic risk to large mammalian herbivores that consume plants 

contaminated by direct spray at the typical application rate and a moderate risk for ingestion scenarios involving 

direct spray at the maximum application rate (Table 3-14; ENSR 2005i). Because it is proposed for use in 

rangelands and has moderate residual activity, livestock may be at risk from the application of this herbicide, 

particularly if it is sprayed throughout the range area. Based on label directions, there are no restrictions on 

livestock use of treated areas.

Sulfometuron methyl: This herbicide is relatively non-selective and would be used on rights-of-way, but it is not 

registered for sites that are grazed. Risk quotients for terrestrial animals were all below the most conservative 

LOC of 0.1, indicating that direct spray or drift of sulfometuron methyl would be unlikely to pose a risk to 

livestock (Table 3-14; ENSR 2005j).

Tebuthiuron: For large mammalian herbivores ingesting food items contaminated by tebuthiuron, there would 

be a low acute and chronic risk if the food was directly sprayed at the maximum application rate (Table 3-14; 

ENSR 2005k). The strength of this herbicide is its use as a habitat modifier in the BLM shrub reduction program; 

it is relatively non-selective but does not tend to harm grasses present. Therefore, impacts to livestock would 

be unlikely with intended use of this herbicide. According to the label for at least one formulation which has 

tebuthiuron as an active ingredient, if a treated area is to be used for haying or grazing, no more than 5 pounds per 

acre of formulation should be applied and the product should not be applied more than once per year.

Effects of Forest Service-evaluated Herbicides

Risk information for the following eight herbicides is taken from Ecological Risk Assessments completed by 

the Forest Service prior to BLM’s completion of the PEIS. As part of its Risk Assessments, the Forest Service 

developed worksheets (SERA 2005b), which allowed the BLM to assess the risks of the herbicides using its own 

maximum application rates and LOCs (rather than the Forest Service rates and LOCs), and to parallel the BLM 

Risk Assessment process as much as possible. However, modeled risk scenarios for terrestrial animals may be 

different from those used for the BLM-evaluated herbicides, depending on the specificity of available toxicity 

data. The assessment of impacts below is presented using the Forest Service upper estimates of Hazard Quotients 

(HQ), to maximize the conservatism of the assessment. In addition, it should be noted that the HQs developed 

by the Forest Service (as well as the BLM) are already conservative for many reasons (e.g., assumption of 100 

percent dermal absorption, assumption of 100 percent of diet contaminated, use of most sensitive values for 

exposure and dose/response assessments). Referenced risk quotients are displayed on Table 3-15.

2,4-D presents a low to moderate acute risk to livestock under several of the direct spray, ingestion, and spill 

scenarios, and a moderate chronic risk for large mammals for consumption of on-site contaminated vegetation 

under both typical and maximum rate (SERA 2006). The Risk Assessment suggests that because large livestock 

eating large quantities of grass and other vegetation are at risk from routine exposure to 2,4-D and because 2,4-D 

is considered for use in rangeland, it should not be applied over large application areas where livestock would 

only consume contaminated food. According to label directions for one formulation, dairy animals should be 

kept out of areas treated with 2,4-D for 7 days. Grass for hay should not be harvested for 30 days after treatment. 

Meat animals should be removed from treated areas 3 days prior to slaughter. Similar restrictions may be in place 

for other formulations.

Clopyralid: Large mammals face low acute risks from direct spray and from consumption of contaminated 

grass at the typical and maximum application rates. The maximum application rate also poses a low chronic 

risk to large mammals consuming on-site contaminated vegetation. All risks identified fall within the lowest 

risk category; adverse effects to livestock are unlikely with expected exposure scenarios. According to label 

directions, there are no restrictions on grazing or hay harvest following application at labeled rates, but livestock 
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should not be transferred from treated grazing areas to susceptible broadleaf crop areas without first allowing for 7 

days of grazing on untreated pasture.

Dicamba: The ingestion of food items contaminated by direct spray of dicamba at the typical and maximum 

application rate would pose a low and moderate acute risk to large mammalian herbivores respectively, and no 

chronic risk (Table 3-15). Because dicamba is proposed for use in rangelands and forestlands and does have 

moderate residual activity, livestock may be at risk, particularly if it is sprayed throughout the range area. Based 

on label directions, there are no restrictions on livestock use of treated areas, other than for lactating animals.

Glyphosate presents a low to moderate acute risk to livestock under several of the direct spray, ingestion, and spill 

scenarios, and a low chronic risk for large mammals for consumption of on-site contaminated vegetation under 

the maximum rate (SERA 2003a). Ingestion of treated grasses could represent a risk, but glyphosate is nonselective and kills grass, suggesting that spot applications in rangeland would be the most appropriate use of this 

herbicide (although risk could occur if invasive grasses were treated when they were young and palatable). Spot 

applications would reduce risks associated with consumption of contaminated vegetation, as fewer non-target 

areas would be impacted by direct spray or spray drift. Based on label directions, there are no restrictions on 

livestock use of treated areas.

Hexazinone: Applications of hexazinone at the typical and maximum application rates would pose a low to 

moderate acute risk to livestock under several exposure scenarios, and a low to moderate chronic risk to large 

mammals under the on-site consumption of contaminated vegetation scenario at typical and maximum rates 

respectively (SERA 1997). According to label directions, livestock should not be grazed, nor forage or hay cut, 

on treated areas for 60 days after application.

Imazapyr applications at the typical application rate should not pose a risk to livestock (SERA 2004d). The 

maximum application rate, however, would pose a low risk under the direct spray of a small animal and 

consumption of contaminated vegetation by large mammal scenarios. Imazapyr is not registered for use in 

rangelands; therefore, it is unlikely that impacts via direct spray or consumption of contaminated vegetation 

would occur. Based on label directions, there are no restrictions on livestock use of treated areas.

Metsulfuron methyl applications at the typical application rate should not pose a risk to livestock (SERA

2004e). Applications at the maximum application rate pose a low acute risk to small animals under scenarios 

involving 100 percent absorption of direct spray and to large mammals under scenarios involving consumption 

of contaminated vegetation. Metsulfuron methyl is registered for use in rangeland, but impacts to livestock 

are unlikely if the typical application rate is used. However, a supplemental label restricts the application on 

rangelands to 0.06 ounces active ingredient per acre.

Picloram poses a low to moderate risk for applications at the typical and maximum application rates for 100 

percent absorption of direct spray by a small animal and acute exposure through consumption of contaminated 

vegetation by a large mammal (SERA 2003b). Picloram is registered for use in rangeland, and can be applied 

over large areas heavily infested with weeds, as its primary targets are broadleaf and woody species. Therefore, 

it might be used to manage certain broadleaved plants without impacting native or other desirable grasses, but 

with the potential to expose livestock. Picloram has a number of restrictions on use in areas grazed by livestock 

or used for cutting hay. In general, livestock should not be grazed on treated areas, nor should hay be cut, for 2 

weeks after treatment.

Triclopyr presents low to moderate risk to livestock under several acute, and two chronic, scenarios, particularly 

through the consumption of contaminated vegetation (SERA 2003c). Because risk categories were determined 

using calculated HQs for the two evaluated forms of triclopyr (triclopyr acid and triclopyr BEE) are the same, no 

Final Environmental Impact Statement, Chapter 4: Livestock
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differentiation is made between these two forms in this section. Triclopyr can be used in rangelands to selectively 

manage woody species without impacting native or other desirable grasses, so broadcast treatments could 

create exposure scenarios if livestock are not removed or the treatment area is limited in scope. There are few 

grazing restrictions for triclopyr, except for lactating dairy cattle. Hay should not be harvested within 14 days of 

application. Although cattle can graze at any time, they would be removed from treated areas at least 3 days prior 

to slaughter.

Effects of Treatments on Forage

Possible adverse indirect effects from increasing herbicide use include reductions in forage amount and preferred 

forage type. However, analysis displayed in the Native and Other Non-Invasive Vegetation section in this Chapter 

indicates the risk to non-target plants is generally low and not dissimilar to the risk from non-herbicide treatments. 

As discussed in the Assumptions about Herbicide Treatments section in Chapter 3, broadcast treatments of 

invasive plants generally occur only with selective herbicides or in areas where invasive plants have essentially 

eliminated the native species. In any event, range conditions would generally benefit from the control of invasive 

plants, and any adverse native vegetation changes would begin to disappear within one to two growing seasons 

after treatment.

Effects of Noxious Weeds on Livestock

The spread of invasive plant populations would likely have harmful effects on livestock. Many studies and repeated 

landowner experiences show that weeds commonly reduce livestock carrying capacity from thirty-five percent to 

ninety percent (Hilken 1980, USDA 1994a). Yellow starthistle forms solid stands that dramatically reduce forage for 

livestock and wildlife. This species causes a fatal neurological disorder (chewing disease) when ingested by horses 

(USDA 2005a:3-9). Spotted knapweed has been found to reduce grass production from 60-90 percent (Harris and 

Cranston 1979, Bedunah and Carpenter 1989, Wright and Kelsey 1997) decreasing carrying capacity for livestock 

and lowering the quality of winter range habitat for wildlife (Rice et al. 1997a). Rangeland that contains excessive 

or unpalatable brush cover is less useful for grazing and has reduced carrying capacity for domestic livestock. 

Similarly, capacity for cattle grazing decreases proportionately with loss of forage caused by weed infestation. 

Economic returns in terms of improved grazing value typically exceed herbicide treatment costs on lands where 

herbicides are used to control weeds (Olson 1999). In addition, some noxious weeds are toxic to livestock including 

common tansy, leafy spurge, Russian knapweed, common St. Johnswort, and yellow starthistle.

Treatments that maintain or reduce the cover of noxious weeds and restore native and other forage vegetation 

on grazed lands would benefit livestock by increasing (or at least slowing the decline of) the number of acres 

available for grazing and the quality of forage. Decline in range condition from invasive weeds would be 

proportional to the acres projected to become infested over time. The differences between the alternatives could 

be expected to have differing effects on grazing capacity over the long term.

Effects by Alternative

Reference Analysis – No Herbicide Use

Under the Reference Analysis, livestock would not be affected by BLM herbicide use. Primary impacts would 

stem from other vegetation treatment methods and/or from the spread of noxious weeds and other invasive plants.

Effects of Invasive Plants: Without herbicides, there would be an increase in the spread of invasive plants, 

increasing the rate at which invasive plants replace native plant communities other non-invasive vegetation 

that livestock depend on for forage. Invasive plants are projected to occupy 2.2 million more acres in 15 years 
265

under the no-herbicide Reference Analysis than under the No Action Alternative (Alternative 2), damaging 

desirable plant communities including rangeland communities that provide forage for livestock. Other factors can 

exacerbate these effects on particular acres. Only about 1/3 of noxious weeds can be effectively controlled using 

non-herbicide methods. For example, it is often difficult to eradicate some species (e.g., resprouting shrubs or 

invasive annual grasses) by non-herbicide methods. In addition, non-herbicide methods can be impractical over 

large areas or in some situations because of cost, time, or public concerns. Large-scale non-herbicide treatments 

can adversely affect native plants, soils and other resources, and lead to a higher likelihood of reinvasion than spot 

or selective herbicide treatments.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Effects of Herbicides: Although herbicides would be applied to fewer acres under this alternative than under any 

of the action alternatives, the potential toxicity of the four herbicides available under this alternative keep this 

alternative from having the least risk for livestock. As noted under Effects Common to All Alternatives above, 

2,4-D and glyphosate present risks to mammals from direct spray and from consumption of contaminated grass at 

the typical and maximum application rates. Inadvertent spraying of grass and other forage near treated invasive 

weeds, as well as drift and other avenues, could result in exposure. Picloram also presents low to moderate risks 

under some exposure scenarios, and dicamba presents a low to moderate risk under food contamination scenarios 

for typical and maximum rate respectively.

Effects of Invasive Plants: Under the No Action Alternative (Alternative 2), native plant communities would 

continue to be impacted by cheatgrass and medusahead spread, decreasing plant diversity, habitat quality, and 

productivity thereby reducing forage for livestock and wildlife. Medusahead rye is a noxious weed infesting an 

estimated 600,000 acres of BLM lands in Oregon; it is considered non-forage for livestock as high silica content 

and other attributes render it unpalatable. The invasive cheatgrass infests another 5 million acres and except for a 

very few weeks early in the season, is similarly unpalatable. The frequency and intensity of wildland fire would 

increase as plant communities continue to become more infested with these two invasive annual grasses. Noxious 

weeds would continue to expand at their current rate, and are projected to infest about 1/3 of the BLM lands in 

Oregon in 15 years.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Effects of Herbicides: Although the acres projected to be treated with herbicides nearly double when compared 

to the No Action Alternative (Alternative 2), total pounds of herbicides applied would decrease 35 percent at 

the typical rate. Use of the four herbicides available under Alternative 2 would decrease by 60 to 80 percent, 

and herbicides generally less toxic to livestock would be used. For example, approximately 1/3 of the projected 

herbicide use under this alternative would be with imazapic, an herbicide with no measured risk to livestock under 

any of the exposure scenarios, and for which no grazing label restrictions apply. Similarly (from Effects Common 

above):

• Chlorsulfuron, fluridone, and sulfometuron methyl risk quotients were all below the most conservative 

LOC indicating that direct spray would not likely pose a risk; and,

• Imazapyr and metsulfuron methyl under typical application rates had no risk to livestock predicted under 

any scenario.

For the other two herbicides available under this alternative, hexazinone presents a low to moderate risk for some 

scenarios, but it is typically utilized for treatment of woody species and is semi-selective with spot application, so 

risk to livestock under normal applications may be lower than those predicted by the Risk Assessment. Triclopyr 

presents low risk through consumption of contaminated vegetation at the typical rate and moderate risk at the 

maximum rate. It is utilized in rangelands due to selectivity for woody species, and has low residual activity.

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The reduced application rates and prohibition of using aerial applications west of the Cascades would 

substantially reduce the impacts of off-site drift to livestock, an exposure scenario that is not specifically modeled 

for the BLM herbicides. (Consumption of contaminated vegetation off-site was modeled for most of the Forest 

Service herbicides, with no risk demonstrated to livestock for any of these herbicides, except dicamba, and for 

triclopyr when applied at the maximum application rate.) The increased number of herbicides available under this 

alternative would lower risk to livestock because more choices would be available to meet site-specific concerns 

including the presence of livestock.

Effects of Invasive Plants: Noxious weeds are projected to infest 1.9 million fewer acres under this alternative 

than under the No Action Alternative (Alternative 2). The option to use more selective and effective herbicides 

for noxious weed control would assist in the eradication of new infestations on BLM lands and also slow the 

spread of larger noxious weed infestations from public land into non-Federal commercial rangelands. Alternative 

3 would provide herbicides that could be used to control invasive annual grasses such as cheatgrass and 

medusahead, which have displaced native grassland communities and negatively impacted livestock grazing 

patterns, seasons of use, and overall operations. This would indirectly help control other invasive plants that are 

either the result of large grass-related fires, or that are otherwise fire dependent and out-compete native vegetation 

in establishing dominance in fire-disturbed sites.

The lack of an aerial spray option west of the Cascades could result in large areas of rangeland remaining 

untreated, which could negatively affect livestock habitat and forage in these areas over the long term.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

Effects described for Alternative 3 would also apply to Alternative 4. Additional effects are described below.

Effects of Herbicides: This alternative is projected to increase acres treated with herbicides by 2.7 times when 

compared with the No Action Alternative (Alternative 2), but increase the total pounds of herbicides used only 

52 percent (at typical rate). Much of the increase is from three herbicides not registered for use on rangeland and 

new to this alternative for vegetation control in rights-of-way and other developments. Bromacil, diuron, and 

tebuthiuron are relatively long-lasting non-selective pre-emergent herbicides that would be used for complete 

vegetation control in and near developments where vegetation is already being kept at a minimum to protect 

the investment and function of the developments. Treatment of recreation and administrative sites under this 

alternative would have little or no impact on livestock since they have limited or no access to these sites, but 

treatments on unfenced rights-of-way and other developments could result in livestock exposure. None of 

the three additional herbicides represent a risk to livestock from direct spray or dermal contact with treated 

vegetation. Ingestion of treated foliage does present risk however; tebuthiuron presents a low risk from mammal 

ingestion scenarios when applied at the maximum rate, and bromacil presents low to moderate risk, and diuron 

presents low to high risks, under several of the ingested vegetation scenarios.

There would also be an increase in acres treated with most of the herbicides available under Alternative 3 along 

rights-of-way where native and other non-invasive vegetation control would better meet maintenance objectives 

(see Administrative Sites, Roads, and Rights-of-Way in this Chapter). Use of the four Alternative 2 (No Action) 

herbicides would remain lower under this Alternative than under Alternative 2.

Wildlife habitat improvement treatments to meet goals specified in Conservation Strategies (e.g., tebuthiuron 

applications to thin sagebrush) could pose a risk to livestock; such risks will be considered at the site-specific 

scale. The availability of 13 to 16 herbicides would provide options for reducing this risk, since about half of the 
267

herbicides available have little or no identified risk to livestock. Tebuthiuron in particular is expected to be used 

in low doses to effect structural changes in sagebrush, but such doses present no identified risk to livestock.

Forage and the Effects of Invasive Plants: The small areas subject to total vegetation removal, such as around 

administrative sites and communications facilities, should have little to no effect on the availability of livestock 

forage. These areas are already low in forage production, as they are currently subject to manual or mechanical 

cutting. In addition, livestock may already be excluded by fences. Range conditions would benefit from 

additional control of noxious weeds. Incidental control of noxious weeds during herbicide rights-of-way 

treatments are projected to reduce the acres infested with noxious weeds in 15 years another 300,000 acres when 

compared to Alternative 3 (See Table 4-4 and Appendix 7).

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Effects described for Alternative 4 (Proposed Action) would also apply to Alternative 5. Additional effects are 

described below.

Effects of Herbicides: It is estimated that an additional 4,800 acres would be treated with herbicides under this 

alternative when compared to Alternative 4, with 2,4-D and imazapic estimated to each account for 35 percent 

of the increase. Treatments would be primarily for wildlife habitat improvement east of the Cascades, although 

a variety of resource management objectives may be accomplished except those designed specifically for 

livestock forage or timber production. Potential livestock exposure would be greatest under this alternative. 

Imazapic presents no identified risk to livestock, but 2,4-D presents risks to mammals from direct spray and from 

consumption of contaminated grass at the typical and maximum application rates.

The two additional herbicides available under this alternative are projected to each be used on 200 acres annually. 

Diflufenzopyr+dicamba risk quotients are all below the most conservative LOC indicating direct spray would 

not pose a risk to livestock. Consumption of vegetation contaminated by direct spray of diquat at the typical 

rate poses low chronic risk and moderate acute and chronic risk at the maximum application rate; therefore, 

livestock could be at risk from short and long-term consumption of contaminated forage. However, because this 

is an aquatic herbicide that is not proposed for use in terrestrial areas, and because the label requires exclusion of 

livestock, the likelihood of livestock exposures is minimal. There is a concern for livestock feeding in wetlandriparian areas where the herbicide would be utilized; risk could be reduced through herding or fencing animals out 

of treatment areas until the herbicide has dissipated.

Forage and the Effects of Invasive Plants: Because Alternative 5 involves the most treatment acres, it could also have 

the greatest short-term adverse impact on livestock grazing operations through temporary closures, although wildlife 

habitat improvement treatments might similarly benefit livestock. Benefits to livestock from the control of noxious 

weeds and other invasive plants would be similar to those described for Alternative 4 (Proposed Action).

Cumulative Effects

Loss of native vegetation and declining ecosystem health on public lands due to noxious weeds and other 

invasive vegetation60 has contributed to reductions in the ability of public lands to support livestock grazing. 

Livestock grazing itself has caused some of these changes. The increased demand for multiple uses on public 

lands has further affected vegetative communities, impacting the land’s ability to support current levels of 

60 And their effect on fire regimes.

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Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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livestock use. Restoring ecosystem processes and rangeland health by reducing invasive plant spread helps 

create and/or maintain plant communities resistant to disturbance and capable of producing livestock forage. 

However, even with treatment, noxious weeds and other invasive plants would continue to spread. The BLM 

would continue to modify grazing to attain rangeland health standards. 

Proposed herbicide use on BLM lands would be a small portion of the existing pesticide use statewide (Table 4-1). In 

general, any herbicide effects to water and other BLM resources will be cumulative to effects from non-BLM uses.

Wild Horses and Burros

Affected Environment

The BLM manages wild horses and burros on public land through the Wild Free-Roaming Horse and Burro Act of 

1971. Wild horses and burros are managed on 18 Herd Management Areas (HMAs) covering 2.6 million acres of 

BLM lands and another 134,000 acres of National Forest, the majority of which is in Harney, Lake, and Malheur 

counties. The Act mandates that wild horses and burros can only be managed in areas where they were found in 

1971. Public lands inhabited by wild horses or burros are closed to grazing under permit or lease by domestic 

horses and burros, but are otherwise open to (and mostly covered by) permits and leases for other livestock 

grazing. Public lands are the primary source of forage for wild horses in eastern Oregon. Typically, the BLM 

does not feed or water the animals, but does intervene during extreme drought, fire, or freezing weather, and may 

relocate animals or remove them from the range during extreme conditions.

Each HMA has an Appropriate Management Level (AML), which is an estimate of the number of wild horses 

and burros that public lands can support while maintaining a thriving natural ecological balance. The combined 

AMLs for the 18 HMAs in Oregon is 1,340 to 2,655 animals. Wild horse herds grow at an average rate of 20 

percent annually. Animals that exceed the AML or that stray onto non-designated public and/or private lands are 

removed (USDI 2007a). As of 2008, wild horse and burro numbers were estimated to be 3,605 animals (about 30 

of which were burros), and the AML was being exceeded in 10 of the 18 HMAs. Excess animals damage range 

conditions, adversely affecting other commodity and non-commodity resource values and generally increasing the 

likelihood of invasive plant establishment. Herd sizes are managed primarily by periodically gathering surplus 

animals. Fertility control is also being used in some HMAs as a means to reduce the population growth rate. In 

FY 2008, 225 wild horses were adopted in Oregon. The main holding facility for wild horses in Oregon is located 

in Harney County just west of Burns, Oregon. The facility serves as a short-term holding area prior to distribution 

to other states for adoption, and includes a public viewing area. Wild horses and burros in Oregon represent about 

5 percent of the total population on BLM lands in ten western states, with the highest numbers being in Nevada 

(46 percent) and Wyoming (13 percent).

Environmental Consequences

The proposed increase in the number of herbicides available and the types of vegetation management activities 

they could be used for could affect wild horses through direct and indirect exposure to herbicides that could harm 

their health, or through temporary decreases in amount of food available. However, any of the action alternatives 

would be expected to improve (or at least slow the decline of) the amount and quality of forage available, 

potentially increasing the carrying capacity of the HMAs and reducing other resource conflicts.
269

Effects Commons to All Alternatives

In addition to the following discussions, effects described in the Livestock section would generally apply to wild 

horses and burros.

Herbicide Effects

The extent of direct and indirect effects to wild horses or burros would vary by the amount of herbicide placed on 

vegetation that is used as forage (which is affected by the formulation and the extent and method of treatment), the 

toxicity of the herbicide, physical features of the terrain, weather conditions, and the time of year (e.g., newborn 

foals and burros would be susceptible during foaling season, with March through June being a critical period). 

Potential adverse direct effects to individual animals because of exposure to herbicides include death, damage 

to vital organs, change in body weight, decreases in healthy offspring, and increased susceptibility to predation. 

Wild horses and burros would have a greater chance of exposure to herbicides—either via direct contact with the 

herbicide upon application or indirect contact via dermal contact with vegetation or ingestion of vegetation—if 

their range extent was partially or completely sprayed. However, these animals are wide ranging, and HMAs are 

often larger than 30,000 to 40,000 acres for Oregon herd areas. Most treatments would be less than 200 acres, 

treat only the invasive plant portion of the vegetation, or be on recently burned areas (e.g., imazapic on newly 

burned areas to control invasive annual grasses).

Wild horses or burros may also experience greater impacts under conditions where herbicide drift is more 

likely, such as in areas where herbicides are aerially sprayed adjacent to herd management areas. The BLM and 

Forest Service Risk Assessments suggested several possible common scenarios where herbicides could affect 

wild horses (Appendix 8). Wild horses consume large quantities of grass and are thus at relatively greater risk 

for harm than smaller wildlife or wildlife that feed on other herbaceous vegetation, seeds, or fruits, which may 

have less herbicide residue than grass (Fletcher et al. 1994), at least where broad-scale applications of selective 

herbicides have been made on invasive plants over native grasses. Thus, 100 percent grass grazing scenarios were 

specifically modeled in the Risk Assessments. However, reaching Ecological Risk Assessment-identified risk 

levels would be unlikely unless the animal forages exclusively within the treatment area for an entire day.

Herbicide exposure to wild horses and burros would also be limited in the following two scenarios. Areas that are 

fenced are generally not accessible to wild horses and burros. In addition, any aerial application would cause wild 

horses to disperse from the immediate area of application for unspecified periods unless a sole water source is in 

the treatment areas. Population management generally consists of aerial census and use of helicopters for gather/

removal operations, so wild horses have a strong tendency to flee when aircraft come in close proximity to the herds.

The discussion of the individual herbicides in the Livestock section also applies to wild horses and burros.

Forage, Invasive Plant, and Other Effects

Adverse indirect effects could include reductions in preferred forage or forage amount. Forage reduction or 

disturbance (particularly aerial) may cause wild horses to move out of herd management areas and onto lands that 

are not legally designated for wild horse and burro management where there may be competition for forage with 

domestic livestock.

Many HMAs are currently above AMLs. Noxious weed infestations can greatly reduce the land’s carrying 

capacity for wild horses, which tend to avoid weeds that have low palatability from defenses such as toxins, 

spines, and/or distasteful compounds (DiTomaso et al. 2006). In addition, some noxious weeds (e.g., horsetail, 

Final Environmental Impact Statement, Chapter 4: Wild Horses and Burros
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 270

wild mustard, poison hemlock, tansy ragwort, yellow starthistle, and common St. Johnswort) are poisonous to 

horses. Grazing can be an effective means of managing certain invasive plants in HMAs. However, if vegetation 

is overgrazed (e.g., as a result of horses in excess of the AML), direct invasive plant control treatments such as 

those involving the use of herbicides may be required to return vegetation to a more desirable composition that 

can be maintained by grazing. Successful weed removal would directly benefit wild horses and burros over the 

long term.

Treatments that reduce the risk of atypically frequent or high-intensity wildfire would also benefit wild horses. 

Rangeland weeds that increase the risk of high-intensity wildfire include cheatgrass, medusahead, diffuse 

knapweed, and perennial pepperweed. Uncontrolled, high intensity wildfires can remove forage from large tracts 

of rangeland, reducing its suitability for wild horse and burro grazing. In some instances, BLM has gathered all 

wild horses in those areas and placed them in temporary holding until resource restoration objectives were met, 

and then returned the horses to those areas.

Effects by Alternative

Reference Analysis – No Herbicide Use

Wild horses and burros would not be affected by BLM herbicide use. However, this no-herbicide strategy would 

be expected to have the greatest continued spread of invasive plants that would replace native plant communities 

that wild horses and burros depend on as forage. Non-herbicide treatments would be effective on smaller 

areas for some species, but ineffective on other species that can only be controlled with herbicides alone or in 

combination with other methods.

Invasive Plant Effects: Without the use of herbicides, invasive plant infestations are projected to continue to 

spread, probably at increasing rates. The increase of invasive plant populations would cause further damage 

to susceptible native plant communities, including rangeland communities that provide forage for wild horses, 

particularly in situations where other treatment methods would not be effective or feasible (e.g., large tracts 

of rangeland or grassland dominated by invasive, re-sprouting shrubs; or areas without enough fine fuels to 

carry prescribed fires). The spread of invasive plant populations would be expected to have harmful effects 

on wild horses; the capacity for wild horse grazing decreases proportionately with loss of forage caused by 

weed infestations. Noxious weeds that are toxic to wild horses, including common tansy, leafy spurge, Russian 

knapweed, common St. Johnswort, and yellow starthistle would increase, further reducing forage and herd 

viability.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Herbicide Effects: Impacts to wild horses or burros (positive and negative) would be similar in nature to 

those that have occurred in the past 18 years. Although herbicides would be applied to fewer acres under this 

alternative than under any of the action alternatives, the potential toxicity of the four herbicides available under 

this alternative keep this alternative from having the least risk for wild horses and burros. 2,4-D and glyphosate 

present risks to mammals from direct spray and from consumption of contaminated grass at the typical and 

maximum application rates. Inadvertent spraying of grass and other forage near treated invasive weeds, as well 

as drift and other avenues, could result in exposure. Dicamba and picloram also presents low to moderate risks 

under some exposure scenarios. The primary targets for these two herbicides are broadleaf and woody species, 

so it can be used to target species infesting native or other desirable grass species without affecting the grass. 

Grazing of these sprayed grasses by horses could result in exposure. 
271

Invasive Plant Effects: Under the No Action Alternative (Alternative 2), native plant communities would continue 

to be impacted by cheatgrass and medusahead spread, decreasing plant diversity, habitat quality, and productivity 

thereby reducing forage for wild horses and burros. Medusahead rye is a noxious weed infesting an estimated 

600,000 acres of BLM lands in Oregon; it is considered poor forage as high silica content and other attributes 

render it unpalatable. The invasive cheatgrass infests another 5 million acres and except for a very few weeks 

early in the season, is similarly unpalatable. The frequency and intensity of wildland fire would increase as native 

plant communities become more infested with these two invasive annual grasses. Noxious weeds would continue 

to expand at their current rate, and are projected to infest about 1/3 of the BLM lands in Oregon in 15 years. 

Given the rate of new weed infestations and spread of established weeds, some HMAs could be functionally lost 

to grazing by wild horses in the next ten years.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Herbicide Effects: Under this alternative, total pounds of herbicides applied would decrease 35 percent when 

compared to Alternative 2 (No Action). In addition, use of the four herbicides available under Alternative 2 

would decrease by 60 to 80 percent, and herbicides generally less toxic to wild horses and burros would be used. 

For example, approximately 1/3 of the projected herbicide use under this alternative would be with imazapic, an 

herbicide with no measured risk to wild horses under any of the exposure scenarios. Similarly,

• Chlorsulfuron, fluridone, and sulfometuron methyl risk quotients were all below the most conservative 

LOC indicating that direct spray would not likely pose a risk; and,

• Imazapyr and metsulfuron methyl under typical application rates had no risk to wild horses predicted 

under any scenario, and imazapyr is not registered for rangeland application and therefore it would be 

unlikely that wild horses would either eat contaminated vegetation or come in direct contact with it.

For the other two herbicides available under this alternative, hexazinone presents a low to moderate risk for some 

scenarios, but it is typically utilized for treatment of woody species and is semi-selective with spot application, 

so risk to wild horses and burros under normal applications may be lower than those predicted by the Risk 

Assessment. Triclopyr presents low risk through consumption of contaminated vegetation at the typical rate and 

moderate risk at the maximum rate. It is utilized in rangelands due to selectivity for woody species, and has low 

residual activity.

The increased number of herbicides available under this alternative would lower risk to wild horses and burros 

because more choices would be available to meet site-specific concerns including the presence of wild horses and 

burros.

Invasive Plant Effects: Noxious weeds are projected to infest 1.9 million fewer acres on BLM lands statewide 

under this alternative than under the No Action Alternative (Alternative 2), proportionately benefitting the 2.6 

million acres of BLM HMAs. The option to use more selective and effective herbicides for noxious weed 

control would assist in the eradication of new infestations on BLM lands. Alternative 3 would provide herbicides 

(particularly imazapic, with no rated risk to wild horses) to control invasive annual grasses such as cheatgrass 

and medusahead, which have displaced native grassland communities and changed wild horse and burro grazing 

patterns, seasons of use and overall herd behavior. This would indirectly help control other invasive plants 

that are either the result of large grass-related fires, or that are otherwise fire dependent and out-compete native 

vegetation in establishing dominance in fire-disturbed sites. Although this would not necessarily restore native 

grasslands and result in increases in available forage for wild horses, it would reduce the spread of invasive plants.

Final Environmental Impact Statement, Chapter 4: Wild Horses and Burros
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Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

Effects described for Alternative 3 would also apply to Alternative 4. Additional effects are described below.

Herbicides Effects: This alternative adds three herbicides for vegetation control in rights-of-way and other 

developments. Bromacil, diuron, and tebuthiuron are relatively long-lasting non-selective pre-emergent 

herbicides that would be used for complete vegetation control in and near developments where vegetation is 

already being kept at a minimum to protect the investment and function of the developments. They are not 

registered for use on rangeland. Treatment of recreation and administrative sites under this alternative would have 

little or no impact on wild horses and burros since access is often limited and human activity would be avoided. 

However, drift and treatments of unfenced rights-of-way and other developments could result in exposure. None 

of these three additional herbicides represent a risk to wild horses from direct spray or dermal contact with treated 

vegetation. Ingestion of treated foliage does present risk however; tebuthiuron presents a low risk from mammal 

ingestion scenarios when applied at the maximum rate, and bromacil presents low to moderate risk and diuron 

presents low to high risks under several of the ingested vegetation scenarios.

There would also be an increase in acres treated with most of the herbicides available under Alternative 3 

both along rights-of-way where selective vegetation control would better meet maintenance objectives (see 

Administrative Sites, Roads, and Rights-of-Way in this Chapter). Use of the four Alternative 2 (No Action) 

herbicides would remain lower under this Alternative than under Alternative 2.

Habitat improvement treatments to meet goals specified in Conservation Strategies could pose a risk to wild 

horses; such risks would be considered at the site-specific scale. Some of these treatments would be done aerially, 

which would cause horses to leave the area. The availability of 13 to 16 herbicides would provide options for 

reducing risk, since about half of the herbicides available have little or no identified risk to horses. Tebuthiuron in 

particular is expected to be used in low doses to effect structural changes in sagebrush, but such doses present no 

identified risk to horses.

Invasive Plant Effects: The small areas subject to total vegetation removal, such as around administrative sites 

and communications facilities, should have no effect on the availability of forage. These areas are already low in 

forage production, and horses and burros do not typically forage close to developments. Range conditions would 

benefit from additional control of noxious weeds. Incidental control of noxious weeds during herbicide rights-ofway treatments are projected to reduce the acres infested with noxious weeds in 15 years another 300,000 acres 

when compared to Alternative 3 (See Table 4-4 and Appendix 7).

The ability to use herbicides for certain habitat improvement projects would reduce the adverse effects of current 

non-herbicide methods including the risk of escaped habitat-improvement prescribed fires.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Effects described for Alternative 4 (Proposed Action) would also apply to Alternative 5. Additional effects are 

described below.

Herbicide Effects: It is estimated that approximately 4,800 additional acres would be treated with herbicides 

under this alternative when compared to Alternative 4 (Proposed Action), with 2,4-D and imazapic estimated to 

each account for 35 percent of the increase. Treatments would be primarily for habitat improvement, although a 
273

Final Environmental Impact Statement, Chapter 4: Fire and Fuels

variety of resource management objectives may be accomplished except those specifically for livestock forage or 

timber production, and a portion of these projects would be in HMAs. Potential wild horse exposure would be 

greatest under this alternative. Imazapic presents no identified risk to wild horses and burros, but 2,4-D presents 

risks to mammals from direct spray and from consumption of contaminated grass at the typical and maximum 

application rates.

Two additional herbicides are available under this alternative, and are projected to each be used on 200 acres 

annually. Diflufenzopyr + dicamba risk quotients are all below the most conservative LOC indicating direct 

spray would not pose a risk to wild horses. Consumption of vegetation contaminated by diquat direct spray at the 

typical rate poses low chronic risk and moderate acute and chronic risk at the maximum application rate, therefore 

wild horses and burros could be at risk from short and long-term consumption of contaminated forage. However, 

because this is an aquatic herbicide that is not proposed for use in terrestrial areas, the likelihood of wild horse and 

burro exposure is minimal. There is a concern for horses feeding in wetland-riparian areas where the herbicide 

would be utilized; this risk could be reduced by herding animals out of treatment areas.

Invasive Plant Effects: Benefits to wild horses from the control of noxious weeds and other invasive plants would 

be similar to those described for Alternative 4 (Proposed Action). Although this program component would not

necessarily restore native grasslands and result in increases in available forage for wild horses and burros, it is 

likely that it would reduce the spread of invasive plants, particularly onto non-Federal grazing lands. Wild horses 

and burros would be expected to benefit from a portion of habitat improvement projects expected to be conducted 

under this alternative.

Cumulative Effects

Loss of native and other non-invasive vegetation and declining ecosystem health on public lands due to noxious 

weeds and other invasive vegetation61 has contributed to reductions in the ability of public lands to support wild 

horses and burros. The wild horses and burros themselves have caused some of these changes. The increased 

demand for multiple uses on public lands has further affected vegetative communities, affecting the land’s ability 

to sustain current levels of wild horse use. Restoring ecosystem processes and balancing wild horse use and 

rangeland health reduces invasive plant spread and helps create and/or maintain plant communities resistant to 

disturbance. However, even with treatment, noxious weeds and other invasive plants would continue to spread. 

BLM would continue to manage wild horses within AMLs to attain rangeland health standards.

Proposed herbicide use on BLM lands would be a small portion of the existing pesticide use statewide (Table 4-1). In 

general, any herbicide effects to water and other BLM resources will be cumulative to effects from non-BLM uses.

Fire and Fuels

Affected Environment

With the exception of cheatgrass, medusahead, and other invasive annual grasses (primarily in the Sagebrush 

Steppe Biome), the effects of invasive plants on fire frequency and intensity are mixed and generally subdued. 

The potential effects of invasive plants on fire regimes and fire behavior is largely dependent on the structure 

and characteristics (flammability) of the plants themselves, and their indirect effect of altering the abundance 

and arrangement of native plant fuels. Invasive plants may reduce fuels in ways that suppress the spread of fire 

61 And their effect on fire regimes.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 274

in ecosystems where fire is desirable; or may increase hazardous fuels in ways that increase fire intensity or 

frequency in ecosystems where it is not (Brooks et al. 2004).

In western Oregon’s grasslands and oak woodlands, natural62 fire frequency, fire line intensities, and fire spread 

are reduced when non-native forbs (such as spotted knapweed and yellow starthistle) become the dominate 

species. Similarly, these fire characteristics decrease when the non-native perennials Scotch broom and 

Himalayan blackberry are present in forest openings, riparian areas, recreational sites, and along roadsides. 

Plant characteristics such as coarser stems, higher fuel moisture content, reduced fuel continuity, and decreased 

ignitability reduce fire behavior and allow for quicker initial containment of fires by suppression resources. 

Perennial grasses such as reed canarygrass found in western Oregon wetland prairies tend to increase fuel loading, 

increasing fire intensities and spread. These changes are localized.

Invasive plants in the Western Forest Biome are generally neither flammable nor continuous enough to constitute 

a major fuel hazard or to have significantly altered the fire regime. Exceptions exist: gorse is credited with having 

contributed to a fatal wildfire burning downtown Bandon in 1936 (Simberloff 1996) for example, and reducing 

fire risk may occasionally be a weed treatment objective in this biome, but these exceptions are not particularly 

significant to the differences between the alternatives in this EIS.

In the Siskiyou, Willamette Valley, and Eastern Forest Biomes, a historic fire return internal of less than 10 years 

was common on many sites and helped maintain oak savannahs and open pine stands. Invasion by non-native 

annual grasses has not substantially changed these fires except perhaps to increase their intensity in the most open 

areas at the lowest elevations (Medford area for example). While the diversity of these ecosystems is certainly 

threatened by the dominance of the invasive plants and by increased wildfire intensity as well, there is not a 

substantial increase in the fire danger or change in the long-term fire regime attributable to the invasive plants 

themselves in these vegetation types. Control of invasive plants in these plant communities to reduce wildfire risk 

is not a need identified in this EIS.

In the Sagebrush Steppe Biome invasive annual grasses have not just increased fuel loading, they have become 

sufficiently established to create a self-sustaining cheatgrass-wildfire regime. Plant invasions that alter fire 

regimes typically do so by altering more than one fuel or fire regime property (Brooks et al. 2004). When 

an invasive plant with a different fire regime is established enough to dominate the landscape, its intrinsic 

characteristics and effects on native plants combine to alter fuel properties sufficiently to shift the historic fire 

regime outside of the reference range of variation. If the new fire regime favors the dominance of the invasive 

plants causing new fuel conditions and negatively affecting native species, an invasive plant/fire regime cycle 

becomes established (Zouhar et al. 2008).

Native sagebrush plant communities in the Sagebrush Steppe Biome were historically made up of sagebrush, 

separated by native forbs and bunchgrasses that retained moisture long into the dry summer season and existed in 

discontinuous bunches, often separated by areas of soil crust (see Soil Resources section in this Chapter). Natural 

fire return intervals in this type were 32 to 70 years (Quigley and Arbelbide 1997:797). In the past 130 years, 

large areas of these sagebrush communities have experienced a total vegetation conversion to fire-prone invasive 

annual grasses, which has converted vast landscapes of native sagebrush steppe to non-native annual grasslands 

(Menakis et al. 2003). The noxious weed medusahead and invasive cheatgrass infest over 5 million acres on 

BLM lands in eastern Oregon (Figure 4-7). Effects in the Eastern Forest Biome are not as severe. However, in 

the Sagebrush Steppe Biome, these grasses can increase horizontal fuel continuity and create a fuel bed more 

conducive to ignition and spread, and have been shown to increase fire frequency and size as well as expand the 

seasonal window of burning (Zouhar et al. 2008). These grasses have increased fuel continuity across large areas 

of contiguous landscape, supporting more frequent and more intense fast-moving fires that are initially difficult to 

contain and result in large landscape fires.

62 “Natural” in this context includes pre-European anthropogenic fires.
275

Figure 4-7. Invasive Annual

Upland

Grasses East of the Cascades

Final Environmental Impact Statement, Chapter 4: Fire and Fuels
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Environmental Consequences

The BLM treats hazardous fuels using a variety of non-herbicide methods on tens of thousands of acres per year 

in Oregon. A full discussion of that program is outside the scope of this analysis; the portion of such treatments 

potentially done with herbicides is small, approximately 1 to 5 percent. Currently allowed herbicide treatment of 

noxious weeds (Alternative 2) could have a fuels treatment objective, but the four herbicides currently available 

are not capable of controlling the most pressing case of the invasive annual grasses in the Sagebrush Steppe 

Biome and elsewhere. Alternatives 3-5 would add imazapic and other herbicides capable of treating this fuels 

problem. Herbicide treatments of native and other non-invasive vegetation to meet fuels reduction objectives 

would be permitted under Alternative 5, but are unlikely to occur.

Herbicides would be used as part of an integrated vegetation management approach. Treatment goals would 

include reducing fire intensity and spread rates to protect resource values and to increase firefighter and public 

safety, and restoring fire adapted ecosystems or fire regimes through the modification of vegetation (fuels) 

structure and composition. Herbicides would be used to help achieve these goals in a number of different ways:

• As a standalone treatment or in combination with other vegetation treatments to change the vegetation 

structure and composition to reduce fire behavior characteristics (rate of spread, fire line intensities) and 

facilitate suppression actions;

• As a follow up or maintenance treatment to mechanical or prescribed fire treatments or post wildfire 

rehabilitation treatments, to either further reduce the fuels hazard or to help control new or existing 

invasions from occurring or spreading; and/or

• To create strategically placed breaks in vegetation (fuel) continuity adjacent to wildland urban interface (WUI) 

communities or where treatment of the entire affected area would be either impractical or too expensive.

Fuels Treatment Program: Prescribed fires and other fuels treatments create disturbances that can be exploited 

by noxious weeds and other invasive plants. Similarly, wildfire suppression techniques can introduce or spread 

invasive plants. The potential for various BLM activities to spread noxious weeds is outside the scope of this 

analysis; these are ongoing programs already covered by integrated vegetation management policies designed 

to prevent and control spread. For example, a management activity with a moderate or high risk of spreading 

noxious weeds is required to have a noxious weed risk assessment that identifies actions to be taken to reduce or 

prevent the spread of noxious weeds (USDI 1992b, Appendix 3 of this EIS). The degree to which these and other 

ongoing management practices might contribute to the spread of invasive plants is considered in the spread rate 

analysis in the Noxious Weeds and Other Invasive Plants section earlier in this Chapter.

Effects Common to All Alternatives

In western Oregon under all alternatives, localized weed treatments would occasionally have a fuels reduction 

co-objective. More likely, weed treatments would occur as a secondary maintenance treatment or as a preventive 

measure in areas previously treated for hazardous fuels within the WUI, or to reduce invasions of particularly 

flammable species along roadsides or within recreational sites and areas of special concern like the CascadeSiskiyou National Monument.

In eastern Oregon, there would be a focus on fuels reduction and restoration of large grass-invaded areas to reduce 

severe fire behavior by restoring natural fire adapted ecosystems. Treatments that would help with the reduction 

of fire would include fuel breaks within the WUI or through the center of large infested areas to help support 

suppression efforts.

The effects of herbicides either as a standalone treatment or in combination with prescribed fire, manual or 

mechanical treatments to reduce fire behavior characteristics of invasive annual grasses are generally localized to the 
277

areas treated. Under each of the alternatives, proposed fuel treatment acres are only a small portion of the identified 

infested areas, and would have little to no effect on the estimated acre annual spread rate. Typical treatments are 

likely to be focused on new or small populations of existing species, advancing edges of larger populations, or the 

use of a brown stripping (removal of vegetation) within or adjacent to WUI or large infested areas.

The most significant parameters for comparing the alternatives is the net change in plant communities dominated 

by invasive annual grasses, and the ability to remove and restore those plant communities to protect high interest 

areas such as the WUI. As discussed in the Noxious Weeds and Other Invasive Plants section earlier in this 

Chapter, the alternatives would variously slow the spread of noxious weeds statewide. Cheatgrass, however, 

is not part of the weed spread rate calculations because it is widespread and not listed as a noxious weed. The 

difficulty in effectively eradicating the noxious weed medusahead is given, in that section, as a reason for 

pessimism in the calculations. Therefore, the 4 million acre difference in predicted noxious weed infested acres 

between the Reference Analysis and Alternative 5 in 15 years (Table 4-4) could overstate the relative differences 

between the alternatives for fire risk; the invasive annual grass spread rate may not be significantly affected by the 

various alternatives. The primary difference between the alternatives would be the ability to reduce fuels and/or 

restore more fire-resistant ecosystems on specific sites of interest.

Effects by Alternative

Reference Analysis – No Herbicide Use and Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious 

Weeds Only

Under the Reference Analysis and Alternative 2 (No Action), manual treatments would be the most effective 

treatment in removing annual grasses. The reduction of non-native annual grasses through mechanical and 

prescribed burning would be limited, however, and dependent on the current condition of the fire regime prior to 

treatment, the intensity, severity, size, and seasonality of a fuel treatment, and site factors such as, topography, 

soil characteristics, and weather conditions (Zouhar et al. 2008). Mechanical methods could create non-vegetated 

or brown stripping in the WUI when opportunities to use prescribed fire are limited. These areas would likely 

require annual maintenance or retreatment to remain effective in reducing the fire risk to communities. This cost 

is likely to keep treatments small in scale, providing protection to limited areas of the WUI.

Prescribed burning can be used to suppress invasive annual grasses in the short term. However, sagebrush steppe 

is very susceptible to reestablishment and increases in abundance of annual non-native grasses after prescribed 

burning unless the site initially had a sufficient component of native perennials to naturally reestablish (Zouhar 

et al. 2008). If a wildfire initially promoted non-native and invasive plants, then using prescribed fire alone to 

reduce the invasion is not likely to be effective. Fire is sometimes more effective when used in combination 

with other treatments (Zouhar et al. 2008). For example, burning cheatgrass and medusahead is most useful 

as a seedbed preparation technique if followed by immediate seeding of desirable (usually native) species. 

These areas need to be planted within a year of the burning or they can become reinvaded (Zouhar et al. 2008). 

Under Alternative 2 (No Action), annual retreatment with herbicides could be utilized to maintain mechanical 

non-vegetated or brown stripping breaks, reducing the cost of maintaining these areas, and increasing their 

effectiveness at reducing fires.

Glyphosate is sometimes used for medusahead control, but does not reduce the seedbank. Because glyphosate in 

non-selective, it removes native shrubs and forbs needed to help restore the site. As with prescribed fire, active 

restoration is usually required. Actual fuel hazard reduction benefits, even in the short term, are limited.

The reduction in the severity of fire behavior characteristics (rate of spread, fire line intensities) under the Reference 

Analysis and Alternative 2 would be relatively labor-intensive, and benefits would be localized to the area treated.

Final Environmental Impact Statement, Chapter 4: Fire and Fuels
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Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Herbicides that would become available under this alternative include pre-emergents (e.g., imazapic) that would 

control invasive annual grasses including cheatgrass and medusahead, making a combination prescribed fireherbicide-seeding treatment effective at removing these grasses and restoring native plants. This treatment could 

be used to meet a variety or restoration objectives but significant to this discussion, the treatment would reduce 

the risk of fast-moving intense grass-fueled fires when applied to meet fuel reduction objectives within the WUI.

Herbicides would also increase the effectiveness of greenstripping – a proactive technique to reduce the 

magnitude of the cheatgrass-wildfire cycle by growing fire-resistant vegetation at strategic locations in order 

to slow or stop the spread of wildfires (Quigley and Arbelbide 1997:801), and would increase the likelihood of 

successfully working with adjacent landowners on fuel breaks and related treatments.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

The effects described for Alternative 3 would also apply to Alternative 4. Alternative 4 would also permit the use 

of herbicides for the control of native and other non-invasive plants around administrative sites. Objectives for 

vegetation treatments around administrative sites such as communications sites and other remote structures include 

keeping wildfire from entering the developed area of the site and destroying structures and other improvements. The 

use of persistent pre-emergent non-selective herbicides such as diuron for these treatments would likely be more 

effective than regular non-herbicide treatments, because better long-term control would be achieved.

Other herbicide treatments permitted under Alternative 4 including most treatments along rights-of-ways would 

probably be neutral regarding their effect on wildfire. For example, it is not clear that sprayed vegetation would 

be any more or less flammable than mown vegetation. Bare-ground treatments immediately adjacent to some 

roadsides east of the Cascades could reduce the incidence of wildfires coming from vehicles, and reduce road 

damage from wildfires.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

In addition to all treatments permitted under Alternative 4 (Proposed Action), Alternative 5 would make 

herbicides available for any vegetation treatment except livestock forage or timber production. In unusual 

circumstances, this might include treatments of native plants to reduce fuel loading.

Timber

Affected Environment

This section addresses the reasonably foreseeable effects of the alternatives on timber volume production from 

BLM lands in Oregon. The effects of the alternatives on the broad ecological function of forests are included in 

the Native and Other Non-Invasive Vegetation section elsewhere in this Chapter.

All alternatives exclude herbicide use specifically for timber production. That means that herbicide use proposals 

will not, either as an objective or as an evaluation criterion, have a site-specific timber volume production 
279

purpose. The noxious weeds and other invasive plants and pest control portion of the alternatives focus on 

stopping new weeds from getting a foothold, preventing existing weeds from spreading to new areas, and 

protecting or restoring susceptible areas such as Special Status species’ habitats. Such treatments could occur in 

recently harvested timber sale units in part because any area is susceptible to invasion, and in part, because site 

disturbances and increased sunlight to the ground increases the likelihood of infestation.

Weed control efforts have the potential to affect future timber growth, much the same way control efforts 

will affect water quality, visual resources, and so forth. Economic effects, including those resulting from lost 

productivity on forestlands within the State are one criterion the State uses when considering whether to designate 

non-native plants as noxious weeds. The action alternatives propose to control Sudden Oak Death, for example, 

even though the objective of that control is both environmental and economic (with respect to the potential for 

protection of timber volume, nursery sales, and other commodity production). To the degree BLM noxious 

weed treatments contribute to the control and elimination of weeds the State and neighboring landowners have 

identified as needing control, the Purpose (Chapter 1) of cooperatively controlling invasive plants so they do not 

infest or reinfest adjacent non-BLM lands, will be furthered.

Existing Timber Volume Production

East Side Dry Forests and Other Woodlands

On most BLM forests east of Highway 97 in central Oregon, forest management activities are conducted to 

promote forest stand health and resiliency to fire, insects, and disease. Treatments include thinning to reduce 

densely canopied young forests, fuels reductions of densely stocked stands resulting from many years of fire 

suppression, fire salvage to reduce fuels and capture surplus mortality after wildfires, and/or uneven age stand 

management to restore pre-settlement stand conditions. While an average of four million board feet (MMBF) per 

year has recently been harvested in the Eastern Forest Biome (two million from the portion of the Klamath Falls 

Resource Area east of Highway 97 and two million from all other), timber volume production per se is not an 

objective of these treatments.

Similarly, some of the Resource Management Plans (RMPs) include management prescriptions and allowable 

commercial forest product sales from woodlands, specifically western juniper.

While the presence of invasive plants certainly affects the health and function of these dry forests and may change 

the need for stand treatments using timber sales, those effects are more appropriately addressed in the Native and 

Other Non-Invasive Vegetation section in this Chapter.

Western Oregon Including O&C Lands

Under the six RMPs adopted in 1995 for BLM districts west of the Cascades, and that portion of the Klamath Falls 

Resource Area west of Highway 97, 607,600 acres63 (about 28 percent of the area’s 2.2 million acres of forested 

lands) are managed for regularly scheduled timber harvest totaling slightly over 200 MMBF per year. The remaining 

forested areas are managed primarily as Late-Successional Reserves and Riparian Reserves that produce some 

timber when thinning and other treatments are needed to achieve those area’s specific management objectives. 

63 These are the lands suitable for regularly scheduled timber harvest in the Matrix and Adaptive Management Area land 

use allocations. Various standards and guidelines applicable to these lands reduce actual acres treated.

Final Environmental Impact Statement, Chapter 4: Timber
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Invasive Plants on Timberlands

A recent compilation of invasive plant information from permanent inventory plots spread across all forestlands 

in Oregon found invasive plants64 made up 6 percent of the crown cover in Oregon forests, and more than 

17 percent in seedling/sapling stands less than 5 inches dbh. The percentage of inventory plots with one 

or more invasive plants present ranged from 100 percent in the Blue Mountains to 47 percent in the Coast 

Range (Donnegan et al. 2008:63-64). Cheatgrass was the most common invasive plant in Oregon forestlands 

(all ownerships) at 196,000 acres, and Himalayan blackberry was second at 149,000 acres (all ownerships). 

Himalayan blackberry is the most common invasive plant in western Oregon. A 2008 compilation by the BLM 

reported 130 invasive plants and 61 noxious weeds on BLM lands west of the Cascades and the Klamath Falls 

Resource Area, with the highest density on the Medford District.

The BLM manages 12.3 percent of Oregon’s forestlands (Donnegan et al. 2008:19). Because BLM forests are 

typically low elevation, and are arranged in a checkerboard pattern with other forestlands and share a common 

road system, the invasive plant percentages included in or inferred from Donnegan et al. (2008) would be 

expected to apply or even under-report conditions on BLM lands.65

Environmental Consequences

This section addresses the effect of the alternatives on timber production, even though the alternatives themselves 

do not include the use of herbicides specifically for timber volume production.

Effects Common to All Alternatives

Effects of Herbicide and Non-herbicide Treatment Methods

The effects of invasive plant treatments themselves, whether accomplished with herbicide or non-herbicide 

methods, are expected to be negligible. Treatments for noxious weeds and other invasive plants are generally 

focused on specific plants, and collateral damage to crop trees is rare. Aerial application, for example, would not 

occur west of the Cascades under Alternatives 3 or 4, and would occur only rarely if at all under Alternatives 2 

or 5. Equipment used to pull larger plants such as Scotch broom can damage or uproot individual conifers, but 

individual tree mortality in timber production plantations is common and usually does not noticeably reduce longterm production unless the site is only marginally stocked. The same damage could occur during spot herbicide 

treatments, and treatments would be designed to avoid damage to non-target plants including conifers. The 

likelihood of damage from herbicide and non-herbicide weed control treatments would decrease as trees get older.

If there are effects to timber production, they would likely be positive “release” type effects as invasive plants 

competing with desirable conifers are removed.

64 The “invasive plant” definition used in the Donnegan report is different than used elsewhere in this EIS. Donnegan et 

al. (2008) considered all species not native to the U.S. and readily recognizable to a trained inventory crew. Thus, it 

includes some species not considered invasive in this EIS, like foxglove, but misses less common noxious weeds. The 

overall numbers are probably reasonably comparable with other numbers in this EIS.

65 Donnegan et al. (2008) numbers would be expected to under-report low elevation checkerboard forests and over-report 

higher elevation more consolidated National Forests because most common invasive weeds favor temperate climates 

and harvest-related disturbances. 
281

Effects of Invasive Plants

Invasive plants adversely affect reforestation and early growth in forest plantations. Invasive grasses like false 

brome use early season soil moisture and reduce first year conifer seedling survival. Most invasive plants are 

early seral species, although large species like Himalayan blackberry and Scotch broom will remain in the stand 

for decades, impacting growth and complicating cultural work such as young-stand thinning. Pole-size and 

larger stands typically shade out early seral invasive plants, and those that are left would likely use only a small 

percentage of site resources. Few if any invasive plants have been reported altering forest soils sufficiently to 

retard reforestation and growth, at least west of the Cascades. Long-lived seeds such as those from Scotch broom 

would typically lay dormant under such conditions, and not germinate unless an opening was created or the stand 

was regenerated again. Scotch broom has been identified as the noxious weed causing the highest productivity 

losses of any of Oregon’s noxious weeds, at $47 million annually (Radke and Davis 2000:19-20).

Invasive plants reduce timber growth as well, but the effect is not as pronounced as it is on adjacent private 

commercial forestlands where rapid growth is the primary objective. In western Oregon, native plants 

quickly reestablish in timber harvest sites and contribute to stand diversity, helping stands to meet a variety of 

management objectives in exchange for some timber volume growth. Invasive plants such as Scotch broom are 

even more efficient than native plants at populating recently harvested sites and being competitive with desired 

conifers. This results in decreased growth, but the effects are gradual; current culturing methods are already 

dealing with some level of invasive plants. Yield predictions are based in part on the performance of existing 

stands, and quantifying the growth loss from the current or future percentage of invasive plants has not been done 

for BLM lands.

In addition to some level of growth loss, any area with noxious weeds is more expensive to manage if for no other 

reason than because mitigation measures must be taken to prevent off-site movement. For example, a requirement 

can be added to the sale contract that equipment be cleaned before it is moved from one area to another. In 

general, risks from harvest activities should be mitigated by the BLM’s policy of requiring the development of 

a noxious weed risk assessment that identifies actions to be taken and monitoring to be done whenever analysis 

of proposed ground disturbing activities determines the activity will have a moderate or high risk of spreading 

noxious weeds (USDI 1992b).

There are other potential effects that are detrimental to timber production. Some invasive plants such as 

Portuguese broom invade and grow faster and more competitively than most native species, and additional 

“release” treatments may be needed to keep the plantations healthy, thereby increasing costs. Some have 

particularly long-lived seeds that are quick to invade disturbed sites (although the seeds of some native brush 

species like manzanita are similarly long-lived). Some have allelopathic influences that poison the soil or 

otherwise slow regeneration and tree seedling growth. Some, such as gorse, create a spiny thicket that foresters 

cannot work in, and that equipment might inadvertently move to other areas. In addition, some regeneration 

treatments (and natural small gap dynamics taking place in areas managed for old-growth and natural processes) 

rely on natural seeding by conifers, and aggressive invasive plants could lower success in these cases, or create a 

need to do more expensive and potentially more ground-disturbing site preparation. Invasive plants can also limit 

the growth of native and other non-invasive plant species important to soil nutrients in the long term, such as the 

nitrogen fixing characteristics of alder, lupines, and ceanothus.

As described in the Noxious Weeds and Other Invasive Plants section earlier in this Chapter, the action 

alternatives are predicted to slow the spread of noxious weeds from a current 12, to 7 and 6 percent annually for 

Alternatives 3 and 4/5 respectively. These reductions would correspondingly reduce the potential for the adverse 

effects listed above.

Final Environmental Impact Statement, Chapter 4: Timber
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 282

Effects by Alternative

Reference Analysis – No Herbicide Use and Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious 

Weeds Only

Continuation of the current (Alternative 2) or even accelerated (Reference Analysis) weed spread rate is predicted 

to result in one-third or more of BLM lands in Oregon infested with noxious weeds in 15 years. While infestation 

rates in the forested lands in western Oregon may lag behind this statewide projection to a degree (Denton 2009), 

problematic weeds such as Scotch Broom, Himalayan blackberry, gorse, yellow starthistle, and others could 

become ubiquitous in the not-too-distant future at this level of control. Decreased growth, increased costs, and 

long-term site productivity losses are likely.

With management responsibility for about ten percent of the current State-designated Sudden Oak Death 

quarantine area in southwestern Oregon, Alternative 2 (No Action) would keep the BLM as the only landowner 

not using herbicides to control the native host plants. Pathologists predict that the likelihood of eventual control 

in that area is being compromised by this limitation. If Sudden Oak Death escapes the current quarantine area and 

becomes widespread, the growth and marketability of certain hardwoods and even Douglas-fir will be negatively 

affected. See Pests and Diseases in this Chapter for more information.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

The additional herbicides available under this alternative would reduce the likelihood of collateral damage to nontarget plants including those being grown for timber. The addition of pests and diseases as an allowable control 

objective would allow the BLM to more aggressively treat its portion of the Sudden Oak Death State quarantine 

area (or any future area designated by the State as a quarantine area), significantly increasing the likelihood of 

eventual containment and control of Sudden Oak Death in Oregon.

The reduction in the spread rate for noxious weeds predicted for this alternative from 12 to 7 percent could 

significantly delay or prevent the adverse effects of noxious weeds on many timber sites.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses and Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation 

Management Objectives

Because of its checkerboard ownership, the BLM shares a road system with other landowners. This road system 

is particularly susceptible to infestation by invasive plants. The current system of spot-spraying noxious weeds 

and then returning to mow other encroaching vegetation is not only inefficient, it risks missing noxious weeds 

that can then be spread by the mowing equipment or spread onto the road where it can be spread by other traffic. 

It is perhaps here as much as anywhere that the additional 25 percent gain in noxious weed control from using 

herbicides to control non-invasive roadside vegetation would apply, decreasing overall weed spread to six percent 

and proportionately benefitting the timber resource for BLM (and adjacent non-Federal timberlands).
283

Final Environmental Impact Statement, Chapter 4: Paleontological and Cultural Resources

Paleontological and Cultural Resources

Affected Environment

In the 1960s, passage of the National Historic Preservation Act (1966) and NEPA (1969) lead to increased 

awareness of the cultural and scientific value of cultural resources and slowed inadvertent loss of those resources 

on public lands. With requirements to inventory and evaluate cultural properties for eligibility to the National 

Register of Historic Places, previously undocumented cultural resources were identified often in response to 

proposed developments or other Federal undertakings. The Archaeological Resources Protection Act of 1979 

provided additional protections for cultural resources on public and tribal lands. In 1990, passage of the Native 

American Graves Protection and Repatriation Act provided protection of American Indian human remains, sacred 

objects and associated funerary objects on Federal and tribal lands. The Paleontological Resources Protection Act 

(PRPA) was signed into law as part of the Omnibus Public Lands Management Act of 2009. Federal agencies are 

required to protect and manage paleontological resources using scientific principles and expertise. In addition, 

the Federal Land Management and Policy Act (FLPMA) of 1976 authorizes the Federal agency to protect public 

resources including those with scientific values. These resources include fossilized paleontological specimens 

on Federal lands. In addition, FLPMA directs the BLM to protect the quality of historical resources and 

archaeological values.

Paleontological Resources

As a natural heritage resource, fossil localities must be considered in developing land use management decisions. 

The fossil record in the western U.S. includes almost all of the geologic periods from the Cambrian (500+ million 

years ago) to the Holocene (about 10,000-12,000 years ago to present). Many of the fossil deposits contain 

specimens of national and international importance and were first made known to the scientific world from 

deposits found in the western U.S.

The BLM manages fossils under the general guidance of the PRPA, FLPMA, and NEPA to promote their use in 

research, education, and recreation. The BLM manages 15.7 million acres of public land in Oregon. Nearly 300 

paleontological localities have been identified on BLM administered land in the State. The fossil record extending 

as early as 100 to 200 million years ago includes some of the richest Paleogene /Neogene (65 million to 1.8 

million years ago) plant and animal fossil localities in the world (USDI 1999:45). Exposures of nearly continuous 

datable geologic sequences offer unique opportunities for scientists to study and understand changing ecology, 

geologic structure, and mammalian evolution.

Cultural Resources

Cultural resources include archaeological, historic, or architectural sites, structures, or places with historically 

significant values and uses, and may include locations (sites or places) of traditional cultural or religious 

importance to specific social or cultural groups. Cultural resources are managed according to their relative 

importance, to protect historically and culturally significant resources from inadvertent loss, destruction, or 

impairment, and to encourage and accommodate the appropriate uses of these resources through planning and 

public participation.

The cultural heritage for public lands administered by the BLM in Oregon extends back 11,000 to 13,000 years 

before the present. The increased number and variety of known cultural properties through time is attributed 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 284

in part to preservation and discovery of cultural materials and to population growth including European and 

Euroamerican exploration and immigration into the Northwest by the early nineteenth century. Cultural sites 

include geological landmarks with American Indian cultural and historical significance, American Indian activity 

sites such as campsites, fish traps, shelters, trails, and pictographs, and Euro-American settlement sites including 

trestles, shipwrecks, buildings, wagon roads, river fords, and mines. Approximately 1.5 million acres of BLM 

administered lands in Oregon have been inventoried for cultural resources and more than 12,000 sites have been 

recorded.

Traditional and Cultural Uses (American Indian Interests)

Some Pacific Northwest Indian tribes have reservation lands held in trust status by the Secretary of the Interior. 

However, of the tribes with interests within the State of Oregon some also have treaty reserved, or Executive 

Order rights upon unoccupied Federal lands outside the bounds of their respective Indian reservations. These 

rights include fishing, hunting, gathering, trapping, and the right to graze domestic livestock. There are also tribes 

without specific off-reservation reserved rights who continue to gather natural resources for traditional or cultural 

purposes (Table 4-21).

Table 4-21. Federally Recognized American Indian Tribes with Interests in Oregon

Tribe Off-Reservation Rights

Klamath Tribes √

Confederated Tribes of the Umatilla Indian Reservation √

Confederated Tribes of the Warm Springs Reservation of Oregon √

Nez Perce Tribe √

Confederated Tribes and Bands of the Yakama Nation √

Confederated Tribes of the Colville Reservation √

Shoshone-Bannock Tribes of the Fort Hall Reservation √

Shoshone-Paiute Tribes of the Duck Valley Reservation √

Fort McDermitt Paiute and Shoshone Tribes √

Burns Paiute

Confederated Tribes of the Coos, Lower Umpqua and Siuslaw Indians of Oregon

Coquille Indian Tribes

Cow Creek Band of Umpqua Tribe of Indians

Confederated Tribes of the Grand Ronde Community of Oregon

Confederated Tribes of Siletz Indians of Oregon

Quartz Valley Indian Community (California)

Fort Bidwell Paiute (California)

The areas of interest to American Indian tribes with off-reservation rights are the lands ceded to the U.S., often 

referred to as “ceded lands.” Historically, some of these lands were occupied by a single specific tribe or band, 

while others were used by several tribes or bands. These ceded lands include most of the Federal lands managed 

by the BLM within the State of Oregon.

Protecting and maintaining plants, animals, fish, and water quality on these lands is an important responsibility of 

the Federal Government. As a land management agency, the BLM has a responsibility to ensure that meaningful 

government-to-government consultation is conducted with Federally recognized tribes to discuss and consider the 

effect that any proposed management action may have on treaty rights and resources.
285

Invasive plants interfere with reserved treaty rights of American Indian tribes of the Pacific Northwest. Invasive 

plants crowd out plants traditionally gathered for food, dress, or ceremonial purposes and can influence wildlife 

and fish numbers and behavior.

Environmental Consequences

Paleontological and cultural resources are nonrenewable, and any damage or displacement from their 

natural context is often irreparable and cumulative. Although fossil resources and many cultural 

resources are often protected from impacts by overlying sediments and deposits, once eroded or otherwise 

physically exposed, the potential for adverse effects greatly increases. All alternatives include treatment 

methods that could affect cultural resources through ground disturbance, increased erosion, or thermal 

alteration. Adverse effects can also result from the herbicide mixes themselves, and from invasive plants. 

Similarly, tribal traditional and cultural use areas can be adversely affected by activities conducted under 

each of the alternatives, and from increases in invasive plants. Effects would be most likely to occur if 

the these resources were not recognized and marked for avoidance by required pre-disturbance surveys 

during the identification or implementation phases or if the project could not be re-designed to avoid 

these resources. In those instances, incidental or inadvertent discovery or impacts to sites could occur but 

measures to document or recover the data from those sites would mitigate those effects to some extent.

In any case, most vegetation treatment options involving ground-disturbing activities would likely 

disturb only the upper few inches of sediments and in many cases would be confined to roads, trails, or 

access routes. Treatment methods causing erosion or soil disturbance could cause indirect impacts to 

these resources but these effects are expected to be minimal. Potential effects would be reduced by predisturbance review and inventory of treatment areas to reduce inadvertent or incidental impacts to cultural 

resources. Consequently, cumulative loss of paleontological, cultural, and tribal use resources on public 

lands due to the proposed vegetation treatments under any of the alternatives is expected to be negligible.

Effects Common to All Alternatives

Paleontological Resources

The effect of vegetation treatments on fossil material would vary with respect to fossil type, minerals, 

degree of fossilization, and exposure. Damage to fossil materials would likely result if wheeled 

equipment used to apply herbicides, or other mechanical methods, or prescribed fire, impacted the site 

directly, exposed it by causing erosion, or created tracks or other access later traveled by recreational 

OHVs. The degree of those effects to fossil resources would depend on the attributes of the fossil 

material, whether the fossil is buried or exposed, and the method of herbicide application. Methods 

involving the use of off-road vehicles could crush fossil material exposed on the surface or increase 

erosion in the fossil localities.

With the exception of some fire or mechanical vegetation treatment methods, impacts to fossil resources 

are unlikely to be substantial. Application of herbicides by wheeled vehicles may crush or displace some 

fossils exposed at or near the ground surface.

Indirect impacts can result from activities that contribute to erosion of fossil bearing sediments that lead to 

exposure of fossils and subsequent discovery as well as advance deterioration or loss of the resource. Direct 

impacts can result from activities that cause ground disturbance or direct harm to the resource. Proposed nonFinal Environmental Impact Statement, Chapter 4: Paleontological and Cultural Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 286

herbicide vegetation treatments including mechanical methods or prescribed fire can produce direct harm through 

crushing or indirect effects from increased erosion or other soil disturbances to fossil resources. This potential 

effect could occur on more than 15,000 acres in the next 15 years under all alternatives.

Cultural Resources

The effect of vegetation treatments on cultural resources depends on the treatment method and the herbicides 

applied. Some herbicide applications can increase soil acidity, which can advance artifact deterioration. Exposure 

of artifacts or other archaeological resources to herbicides is expected to be minimal; however, herbicides 

containing alkyl, biphenyl, or other compounds that contain C12 and C14 could contaminate carbon samples from 

exposed cultural materials commonly used for dating (Fink and Zietz 1996:473). In addition, the herbicide can 

affect surfaces of masonry structures, pictographs, or petroglyph panels if not removed soon after exposure.

Cultural resources are distributed unevenly over the landscape. Areas with high probability for sites associated with 

pre-contact or historic use are generally predictable but locations of specific sites or subsurface cultural resources are 

generally unknown without an inventory. Numerous cultural resources have been identified but many more remain 

unknown until either exposed by erosion or identified by inventory and excavation. Cultural resources often occur 

on or near the ground surface and can be easily impacted or damaged by ground disturbing activities. The more 

surface disturbance that occurs, the greater the potential for cultural resource site disturbance.

Traditional and Cultural Uses

None of the alternatives would change, restrict, or abrogate treaty reserved or Executive Order rights. However, 

implementation of one of the action alternatives may affect food or other natural resources on which the tribes 

depend. Herbicides can harm plants used by American Indians and can affect the health of the people who gather, 

handle or ingest recently treated plants, fish or other animals contaminated by the herbicides. Since traditionally 

gathered plants and animals may occur near vegetation treatment areas, drift from herbicide treatments may occur 

in areas utilized by American Indians.

In some instances, plants traditionally used by American Indians for subsistence, religious or other uses may 

not be avoided by vegetation treatments. Whether the plants are affected due to the treatment method selected 

or the objectives of the treatment (i.e., western juniper control) or through incidental contamination from drift, 

some traditional use plants may be negatively affected. Herbicide residue left on plants, in the water or other 

food sources could result in health risks through ingestion, contact, or other exposure to the herbicides from the 

herbicide treatments.

Effects by Alternative

Reference Analysis – No Herbicide Use

There would be no risk of BLM authorized herbicide treatments drifting onto non-target plants of historical 

importance or of traditional value to American Indian people, and no risk of exposure through contact or ingestion.

Invasive Plants: Noxious weed management without herbicides would, it is estimated, increase the spread rate of 

noxious weeds and other invasive plants and result in 2.7 million more acres infested with noxious weeds in 15 

years than the No Action Alternative (Alternative 2). In addition, because only about 1/3 of the noxious weeds 

on BLM lands can be effectively controlled with non-herbicide methods, the ability to respond to specific weed 

problems in traditional tribal use areas is reduced. Weeds and other invasive vegetation would continue to displace 
287

native species that are desirable to traditional American Indian activities, and would adversely affect the quality 

forage and cover for wildlife utilized by tribes (see Wildlife Resources section in this Chapter). Gathering areas 

for cultural plants, first foods and medicinal plants would be adversely impacted. Cultural features, historical and 

traditional use areas would also be impacted forcing traditional users to seek other, non-traditional areas. The 

spread of invasive plants from BLM lands to Tribal lands would affect existing uses and Tribal interests.

Noxious weed invasion would increase risks to paleontological and cultural resources through increased erosion, 

reduced shading, changes in soil pH, and other environmental changes.

Site Disturbance: Under the Reference Analysis, 8800 acres of directed livestock, 3700 acres of prescribed fire 

for weed control, and 5100 acres of mechanical treatments would be expected, all of which have a higher risk of 

affecting sites through ground disturbance than most herbicide application methods (Table 4-22). Although fewer 

acres would be treated for weeds in this strategy than under Alternative 2 (No Action), the number of acres to be 

treated by directed livestock and mechanical methods (and thus potentially resulting in site disturbance) would 

increase. While this acreage is only slightly higher overall than under Alternative 2, the number of acres that 

would be disturbed by the most impacting mechanical treatments and directed livestock, would be significantly 

greater (31 percent and 68 percent respectively) than under Alternative 2.

Table 4-22. Vegetation Treatment Methods Contributing to Ground Disturbance

Method

Reference 

Analysis

Alt 2 (No 

Action) Alt 3 Alt 4 (Proposed Action) Alt 5

Invasive Invasive Invasive Invasive & 

wildlife

Rights-ofwayInvasive & 

all other

Rights-ofway

Herbicides Applied by 

OHV1 0 5567 10100 11900 0 13533 0

Mechanical Methods 5100 3500 3200 20032 -84603 9744 -84603

Fire 3700 5700 12500 12500 12500

Livestock 8800 2800 2800 2800 2800

Total acres 17600 17567 28600 20743 21347 1

 33 percent of total herbicides applied

2

 3200 acres of invasive plant treatment minus 1197 acres of wildlife treatments. Under Alternative 2, these treatments are 

done mechanically; under Alternative 4, these treatments are done with herbicides

3

 8460 acres of right-of-way work. Under Alternative 2, these treatments are done mechanically; under Alternative 4, these 

treatments are done with herbicides

4

 3200 minus 2226 acres of wildlife treatments. Under Alternative 2, these treatments are done mechanically; under 

Alternative 4, these treatments are done with herbicides

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Herbicides: The risk to human health associated with use of glyphosate, picloram, and dicamba is zero for most 

exposure scenarios, low for consumption of water contaminated with a spill at the maximum rate. Risk is low 

to moderate for 2,4-D under some scenarios including consumption of water contaminated with a spill. For 

American Indians gathering traditional resources, exposure to herbicides would be expected to be lowest of 

any of the alternatives because fewer acres would be treated, however the high number of acres of 2,4-D in this 

alternative could result in inadvertent contact and risk to these users.

Invasive Plants: Noxious weed treatments under this alternative are predicted to be twice as effective at 

eliminating weed populations as methods available under the Reference Analysis (see Noxious Weeds and 

Final Environmental Impact Statement, Chapter 4: Paleontological and Cultural Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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other Invasive Plants section earlier in this Chapter). However, noxious weeds would be expected to continue 

spreading at their current 12 percent rate and infest approximately 1/3 of all BLM lands in Oregon in 15 years. 

This continued spread of noxious weeds would proportionately negatively affect traditional gathering areas as 

native vegetation is displaced by weeds.

Site Disturbance: Adverse effects from non-herbicide treatment methods (directed livestock, mechanical, and 

prescribed fire) would be reduced when compared to the Reference Analysis. Approximately 2800 acres of 

directed livestock, 5700 acres of fire treatments, and 3500 acres of mechanical treatments would be expected, all 

of which have a higher risk of affecting sites through ground disturbance than most herbicide application methods 

(Table 4-22). In this alternative, 5567 acres of herbicide application by OHV is estimated. Treatments using 

OHVs pose a risk of disturbance to paleontological resources and cultural resources, but the risk is less than with 

the above non-herbicide methods.

For paleontological and cultural resources, prescribed fires of low severity would be expected to result in fewer 

impacts to artifacts or other archaeological resources. Impacts from broadcast seeding would be negligible but 

disturbances from drill seeding could result in additional adverse effects.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Herbicides: Under this alternative, glyphosate would be applied to fewer acres statewide and 2,4-D, dicamba, and 

picloram would be used to treat fewer acres east of the Cascades, than under the No Action Alternative (Alternative 

2). While herbicide exposure for American Indians utilizing vegetal resources in treatment areas would be expected 

to increase as more areas are treated with herbicides, most of the herbicides proposed are of lower risk to human 

health at typical application rates. In addition, the reduction in the acres for use of 2,4-D and exclusion of aerial 

spraying west of the Cascades would reduce potential health risks in Alternative 3, although aerial spraying would be 

uncommon in known American Indian plant collection and use areas under any of the alternatives.

Invasive Plants: The additional treatment acres estimated for this alternative and the increased effectiveness of 

those treatments because of the wider array of herbicides available would be expected to slow weed spread to 

7 percent annually and results in 1.9 million fewer acres infested in 15 years. Reducing the spread of noxious 

weeds could benefit traditional gathering areas as displacement of native vegetation by weeds is slowed. Having 

herbicides capable of effectively controlling 116 of the 120 State listed noxious weeds in Oregon, as well as 

other invasive plants, would allow targeting of specific weeds creating specific resource problems, such as those 

infesting susceptible or important use areas.

Site Disturbance: In this alternative, 10,100 acres would be treated with herbicides by OHV. Approximately 

2800 acres of directed livestock, 12,500 acres of fire treatments, and 3200 acres of mechanical treatments would 

be authorized, all of which have a higher risk of affecting sites through ground disturbance than most herbicide 

application methods (Table 4-22). A total of 28,600 acres would be treated by methods that may result in impacts 

to cultural and paleontological resources by ground disturbance, the most acres of any of the alternatives. The 

number of acres proposed for treatment potentially resulting in disturbance to cultural and paleontological sites is 

approximately 39 percent higher than under Alternative 2 (No Action).

The number of acres treated by prescribed fire east of the Cascades, and acres of seeding and planting would 

increase in this alternative. Following prescribed fire treatment, hunting and plant gathering pursuits would be 

temporarily limited and possibly shifted to other areas during recovery. Fire treatments would be used primarily 

for invasive plant control where target plants are resistant to fire or are absent or sparse in the treatment area. 

Therefore, impacts to plants of traditional value or to sites would be limited.
289

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

About two thirds of the increased number of acres treated in this alternative address management 

objectives for controlling non-invasive vegetation in rights-of-way, recreation sites, and administrative 

sites. While acres of herbicide treatments would increase in those areas, a corresponding reduction in 

non-herbicide treatments would result.

Herbicides: Six herbicides (2,4-D, glyphosate, picloram, imazapic, metsulfuron methyl, and triclopyr) 

would be used for more than 75 percent of herbicide treatments in this alternative.

The risk to human health associated with use of glyphosate, picloram, imazapic, metsulfuron methyl, and 

triclopyr at typical application rates is low or zero. Risks to human health are low to moderate for 2,4-D 

under some scenarios, but the herbicide would be reduced to ounces per acre and would be used in tank 

mixes for approximately 50 percent of the acres projected. Bromacil and diuron would be added by this 

alternative and have high health risks to humans under most exposure scenerios, but these herbicides 

would be used for bare-ground treatments adjacent to roads and other developments, not on previously 

undeveloped areas or areas traditionally used for tribal gathering. The broader mix of herbicides would 

increase the options for appropriately managing vegetation while minimizing the risk to humans including 

American Indians gathering traditional resources near the treatment areas.

The increased number of acres treated with herbicides would result in slightly more acres temporarily 

closed to traditional hunting and plant gathering following herbicide treatments than Alternative 3. Most 

of the increased acres are for rights-of-way and other developments, but about 5,700 acres are projected 

for habitat treatments.

Invasive Plants: Although treatments targeting invasive plants are assumed to be the same under this 

alternative as under Alternative 3, incidental control of invasive plants along roadsides while controlling 

encroaching non-native vegetation would further reduce the spread of noxious weeds. Weed spread is 

projected to be reduced to 6 percent, and there would be 300,000 fewer infested acres in 15 years when 

compared to Alternative 3 (See Table 4-4 and Appendix 7). Despite the short-term effects and/or area 

closures resulting from herbicide treatments, the long-term objective of reducing the spread of noxious 

weeds would benefit traditional gathering areas as displacement of native vegetation by weeds is slowed.

Many designated wild and scenic rivers and some Areas of Critical Environmental Concern (ACECs) 

contain cultural sites and other tribal use areas, and these areas are often crossed by utility lines or 

pipelines or include roads and railroads where right-of-way vegetation treatments with herbicides could 

be expanded. The incidental control of noxious weeds by the herbicide use proposed could potentially 

decrease the spread of noxious weeds and other invasive plants into or within culturally significant areas.

Site Disturbance: Under Alternative 4, 11,900 acres would be treated with herbicides by OHV. Approximately 

2800 acres of directed livestock, 12,500 acres of fire treatments, and 2003 acres of mechanical treatments would 

be expected, all of which have a higher risk of affecting sites through ground disturbance than most herbicide 

application methods (Table 4-22). A total of 20,743 acres would be treated by methods that may result in impacts 

to cultural and paleontological resources by ground disturbance, approximately 27 percent lower than Alternative 

3, but 15 percent higher than under Alternative 2 (No Action). Herbicide treatments of rights-of-way, recreation 

sites, and administrative sites would be unlikely to impact cultural and paleontological resources.

Final Environmental Impact Statement, Chapter 4: Paleontological and Cultural Resources
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Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Herbicides: In addition to the herbicides identified in Alternative 4 (Proposed Action), two additional 

herbicides, diquat and diflufenzopyr + dicamba, would be available under Alternative 5, and bromacil, 

chlorsulfuron, and tebuthiuron would be authorized west of the Cascades. All herbicides could be 

used for any vegetation management objective except livestock forage and timber production. Most of 

the increased acreage in this alternative would likely go toward habitat improvements not included in 

Alternative 4.

This alternative would have the greatest short-term impact on traditional gathering areas, primarily by 

resulting in the temporary closure of more lands. Along with these closures, opportunities for collection 

of plant materials would likely be reduced more than under other alternatives. Although only a small 

portion of the acres treated using herbicides would occur in known culturally significant areas, more acres 

and areas would be treated under this alternative than the other alternatives.

Diquat, bromacil, and diuron pose the most severe human health risks and would increase risk to 

American Indian health if herbicides were ingested from plants that were collected in the treatment areas 

under this alternative. However, diquat would be used as an aquatic herbicide, and bromacil and diuron 

use would be along roadsides and around other developments, so they should not pose a significant risk.

Invasive Plants: As with Alternative 4 (Proposed Action), weed spread is projected to be reduced to 6 

percent, and there would be 300,000 fewer infested acres in 15 years when compared to Alternative 

3. Despite the short-term effects and/or area closures resulting from herbicide treatments, the longterm objective of reducing the spread of noxious weeds would benefit traditional gathering areas as 

displacement of native vegetation by weeds is slowed.

Site Disturbance: In Alternative 5, 13,533 acres would be treated with herbicides by OHVs. 

Approximately 2800 acres of directed livestock, 12,500 acres of fire treatments, and 974 acres of 

mechanical treatments would be expected, all of which have a higher risk of affecting sites through 

ground disturbance than most herbicide application methods (Table 4-22). The acres of vegetation control 

potentially resulting in disturbance to sites are greater under this alternative (21,347) than the Proposed 

Action, Alternative 4 (20,743).

Cumulative Effects

Paleontological resources (fossils) are nonrenewable and once damaged or displaced from their natural context, 

the damage is often irreparable and cumulative. Although about 300 fossil localities have been identified on BLM 

administered lands in Oregon, the location of fossils is predictable only to a limited extent. The locations of many 

paleontological resources remain unknown.

Past effects result from natural erosion as well as purposeful and inadvertent damage from public land uses. 

Scientific research as well as “collectors” have contributed to past destruction, removal and displacement of fossil 

resources. Prior to the 1970s, inadvertent damage resulting from various land development and management 

activities occurred. With increased awareness of the scientific value of the resource, and development of 

regulations requiring inventory and prohibiting unauthorized removal of scientifically important and unique fossil 

resources, the cumulative loss of paleontological resources has slowed.
291

Cultural resources including archaeological and historic sites and materials and properties of traditional cultural 

and religious importance are vulnerable to cumulative effects from a variety of activities. Archaeological sites 

can be impacted by erosion, construction, looting, excavation, and activities that alter or destroy features or 

remove artifacts or other cultural materials from their depositional context. Cultural properties including sites of 

the built environment, and properties of traditional importance, hunting and fishing sites, graves, and religious or 

ceremonial sites may lose their integrity and cultural significance when they are degraded as a result of natural or 

human caused disturbance processes or when access to the properties is lost so that the people who value them 

can no longer access them resulting in the loss of people’s connection to those places over time.

Numerous processes including deposition, erosion, re-use and deterioration has affected artifacts and other 

cultural materials through time. As natural processes destroyed, deformed, or re-deposited cultural materials and 

as peoples reused found objects or features, the nature of sites and other cultural resources have been affected. As 

Euro-American settlement advanced into the region, American Indian peoples were displaced and sites were often 

further altered, damaged, or destroyed. As Euro-American settlements advanced, land disturbances largely from 

grazing, timber harvest and mineral exploration and extraction resulted in wide scale impact and loss to cultural 

properties and life ways.

Cumulative impacts to paleontological and cultural resources from vegetation treatments would be least under the 

No Action Alternative (Alternative 2) and greatest under Alternative 3 due to the number of acres that could be 

impacted by ground disturbing activities (Table 4-22). The remaining alternatives would be intermediate between 

these two alternatives. Most vegetation treatment options involving ground-disturbing activities likely would 

disturb only the upper few inches of sediments and in many cases would be confined to roads, trails, or access 

routes. Treatment methods causing erosion or soil disturbance could cause indirect impacts to paleontological 

resources but these effects would be minimal. Potential effects would be reduced by pre-disturbance surveys 

and inventory of treatment areas to identify fossil resources, and by designing treatments to avoid impacts to 

paleontological resources. Consequently, cumulative loss of paleontological and cultural resources on public 

lands due to actions under any of the alternatives is expected to be negligible.

Tribal uses are adversely affected by the spread of noxious weeds and displacement of plants and animals of 

traditional importance. Ground disturbing activities including resource extraction, grazing, motorized vehicles, 

and other land disturbing activities increase impact to cultural resources. Proposed vegetation treatments that 

increase the number of acres to control the spread of noxious weeds and non-invasive vegetation can result in 

short-term impacts by temporarily limiting access to traditional resources by American Indian tribes but long-term 

benefits for improved habitats and plant communities can also be realized. The cumulative impacts to cultural 

resources from the proposed vegetation treatments would be least under the No Action Alternative (Alternative 

2) and greatest under Alternative 3 based on the number of acres that could be impacted by ground disturbing 

activities. The remaining alternatives would be intermediate between these two alternatives. Prescribed fire 

and mechanical treatment methods would be anticipated to have the greatest short-term impacts to wildlife and 

habitats. Acres treated using mechanical methods would be the lowest in Alternative 4 (Proposed Action) and 

Alternative 5. Acres to be treated by prescribed fire would be similar in Alternative 3, 4, and 5, and each would 

treat more acres east of the Cascades and fewer acres west of the Cascades than Alternative 2.

Alternative 5 would authorize the greatest number of acres of vegetation treatment with short-term impacts resulting 

from temporary closure of treatment areas and long-term benefits from more effective and efficient weed treatments, 

and could result in the greatest risk to American Indian health from exposure or ingestion of herbicides. Alternative 

2 (No Action) would treat the fewest acres with herbicides, and Alternative 3 would treat the fewest acres with 

herbicides having a moderate (or high) risk to American Indian health. However, these alternatives would be less 

effective than Alternative 4 at controlling vegetation and plants of value to American Indian tribes.

Final Environmental Impact Statement, Chapter 4: Paleontological and Cultural Resources
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Completion of cultural resource reviews, inventories and consultation with American Indian tribes in areas likely 

to include cultural resources and traditional cultural values prior to vegetation treatments would reduce potential 

effects to cultural resources under all alternatives. Pre-disturbance site identification methods and avoidance 

or other protection methods would reduce the chance that significant cultural resources would be impacted and 

would result in negligible cumulative impacts to cultural resources.

Visual Resources

Affected Environment

The public lands administered by the BLM in Oregon contain many outstanding scenic landscapes. Vast areas 

of forested land, grassland, shrubland, canyon land, and mountain ranges provide scenic views to recreationists, 

visitors, adjacent landowners, and those just passing through. Activities occurring on these lands, such as the 

treatment of invasive plants and other vegetation, have the potential to impact scenic values.

The BLM uses a system called VRM (Visual Resource Management; Manual 8400) to systematically identify 

and evaluate scenic values to determine the appropriate level of scenery management (USDI 1984b). The BLM 

Visual Resource Inventory Handbook (Handbook 8410-1; USDI 1986a) sets forth the procedures for inventorying 

scenic values and establishing VRM objectives, referred to as Management Classes. These ratings are then used 

during the land use planning process and considered along with other resource objectives to determine final 

VRM objectives, or classes. BLM policy requires that every acre of BLM land be inventoried and assigned a 

VRM class ranging from Class I to Class IV. After VRM classes have been established, BLM policy requires all 

management activities to be designed to meet the assigned class objectives. Class IV allows for the most visual 

change to the existing landscape, while Class I allows the least. In Oregon, there are approximately 2.7 million 

acres in VRM Class I and approximately 750,000 acres in VRM Class II. Several Standard Operating Procedures 

apply to reducing the visual impact of herbicide and other treatments such as designing treatments in Class I and 

Class II VRM areas so they do not attract attention of the casual viewer (Appendix 2).

In Oregon, it is estimated that 1.2 million acres of BLM administered lands in Oregon are infested with noxious 

weeds and another 5 million are infested with other invasive plants, increasing at a rate of 12 percent per year (see 

Noxious Weeds and other Invasive Plants section in this Chapter). In these infested areas, the native vegetation 

has been replaced, dominated, or significantly altered by one or more invasive plants, leaving the areas in an 

unnatural state that are assumed in this analysis to be visually degraded. The BLM uses guidance found in the 

Visual Resource Contrast Rating Handbook (Handbook 8431-1; USDI 1986b) to make such determinations 

of landscape quality and character. The handbook provides an objective and consistent method for describing 

landscape character, evaluating visual effects of activities, and developing mitigation to meet VRM objectives. 

The contrast rating process involves describing the landscape in the context of the basic environmental design 

elements and features that comprise it. The elements of form, line, color, and texture are used when describing 

and evaluating landscapes. Activities or modifications in a landscape that repeat these elements are considered to 

be in harmony with their surroundings. Modifications that contrast with their surroundings are considered not in 

harmony with their surroundings.

Environmental Consequences

The visual effects of vegetation treatments are dependent on a variety of factors including the existing visual 

condition of the area, the method of treatment used, the time of year the treatment is conducted and the size of 

the area treated. The use of herbicides have the short-term effect of creating browned and dead vegetation with 
293

Final Environmental Impact Statement, Chapter 4: Visual Resources

the long-term effect of reducing the spread of the targeted species and therefore improving the overall health and 

visual quality of the landscape.

Effects Common to All Alternatives

Effects of Invasive Plants

Based on principles outlined in BLM’s Visual Resource Contrast Rating Handbook (USDI 1986b), this EIS makes 

the assumption that diverse, native-dominated communities are more visually appealing than plant communities that 

have been overtaken by monocultures of weeds or other undesired species66. The weed spread rate analysis in the 

Noxious Weeds and Other Invasive Plants section in this Chapter determined that for every acre of weeds effectively 

treated (eradicated), 10 fewer acres are infested 15 years from now, providing a corresponding benefit to visual 

resources.

Effects of Treatments

Conversely, it is also recognized that all methods of invasive plant treatments have the potential to impact 

visual resources in the short term (1-3 years). The alternatives in this EIS differ in terms of the types and 

amounts of invasive plant control and, therefore, the visual impacts of these alternatives. In Oregon, there are 

approximately 2.7 million acres in VRM Class I and approximately 1.1 million acres in VRM Class II. Of these 

acres, 0.6 million acres are outside of Wilderness and Wilderness Study Areas, Wild and Scenic Rivers, National 

Monuments, Areas of Critical Environmental Concern, Outstanding Natural Areas, Steens Mountain Cooperative 

Management and Protection Area, and Research Natural Areas and similarly designated areas where following the 

underlying direction for the area would automatically achieve the VRM objectives.

Mechanical treatments such as mowing and the use of chainsaws have the short-term visual effect of cut and 

browned vegetation and stumps. Blading and disking produces the visual effect of tilled and disturbed soil in the 

short term. The use of these mechanical methods usually occurs on an annual basis and therefore this visual effect 

is cyclical in nature with no long-term change in the visual quality of the treatment area. The mechanical portion 

of the non-herbicide treatment acres for each alternative in all VRM classes are listed below. As noted on the table, 

no attempt has been made to quantify the tens of thousands of acres of native vegetation treatments currently being 

done by the BLM in Oregon for all resource objectives. However, for Alternatives 4 and 5, herbicide use would 

replace approximately 9,657 and 10,686 acres of mechanical treatments respectively, so these are shown as negative 

numbers, or reductions, in the amount of mechanical treatments currently being done (Table 4-23).

Manual methods of treatment such as pulling, digging, and grubbing weeds focus on the removal of only the 

unwanted vegetation and therefore there is very little short-term visual impact from this activity, although there is 

the potential for some trampling of non-target vegetation and soil disturbance to occur (see Table 4-23).

Prescribed fire treatments result in a short-term visual effect of a burned-over, charred, and blackened landscape. 

Prescribed fire as a weed control treatment is normally applied where invasive plants dominate the landscape, 

and thus few native species would be lost because of the treatment. These treatments are typically followed by 

reseeding the area with native vegetation, which results in new growth in the next growing season, with the longterm positive effect of creating a native species-dominated vegetation landscape (see Table 4-23).

The use of directed livestock for weed control (such as the use of grazing goats to treat invasive vegetation) 

results in the visual effect of a grazed area with limited short-term visual impact (see Table 4-23).

66 It is acknowledged that the yellow flowers of Scotch broom, gorse, and other weeds can be visually appealing to many 

people, and the effects described in this section might also be considered from that standpoint.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 294

Effects from biological agent releases such as insects, pathogens, or other organisms to feed upon the targeted 

weed species occur gradually and are thus almost imperceptible as their impact on the invasive plant may occur 

over an entire growing season or several growing seasons. Over the long term, their removal of the targeted 

invasive vegetation will result in a more native dominated system that is visually appealing (see Table 4-23).

The visual effects of using herbicides to treat invasive vegetation vary depending on which herbicide is applied 

and how it is applied (Chapter 3). Where herbicides are applied directly to the invasive plant using a backpack 

sprayer or wicking method, the short-term (up to several months, depending on the season) visual impact is 

from browned and dead vegetation mixed with green, native vegetation and therefore the impact is not very 

dramatic or easily discernable. When non-selective herbicides are applied aerially or with a boom sprayer, the 

resulting short-term visual effect is one of an open, browned landscape. For invasive weed treatments, such 

treatments are usually restricted to areas where invasive weeds dominate the landscape and natives are either 

resistant to the treatment being applied or the treatment is in conjunction with seeding native species or equivalent 

restoration treatment. In eastern Oregon, there are also opportunities to treat an area after a wildfire to prevent the 

introduction of such invasive plants as cheatgrass and medusahead. In these situations, the visual quality of the 

area has already been diminished by the wildfire and the application of the herbicide after such an event does not 

further degrade the visual character of the area. For example, approximately 11,500 of the 13,600 acre projected 

herbicide use increase between Alternatives 2 and 3 would be imazapic applied aerially east of the Cascades 

in areas heavily infested with invasive annual grasses such as cheatgrass and medusahead, and most of these 

treatments would follow wild or prescribed fire (see Table 4-23).

In addition, 9,300 acres of the additional herbicide acres between Alternative 3 and 4 are non-selective safety 

and maintenance treatments along rights-of-ways and around other improvements. However, all of these (and 

a portion of other treatments proposed under Alternative 4 [Proposed Action]) replace non-herbicide methods 

Table 4-23. Estimated Annual Treatment Acres by Alternative

Reference 

Analysis

Alt. 2 (No Action) Alt. 3 Alt. 4

(Proposed Action)

Alt. 5

Mechanical 

Invasive Vegetation 5,100 3,500 3,200 3,200 3,200

Native Vegetation Unknown1 Unknown1 Unknown1 -9,6572 -10,6862

Manual

Invasive Vegetation 3,500 2,200 2,200 2,200 2,200

Native Vegetation Unknown1 Unknown1 Unknown1 -1,9082 -2,5942

Prescribed Fire

Invasive Vegetation 3,700 5,700 12,500 12,500 12,500

Directed Livestock 

Invasive Vegetation 8,800 2,800 2,800 2,800 3,000

Bio-control

Invasive Vegetation 400 300 200 200 200

Herbicide

Invasive and Native 

Vegetation

NA 16,700 30,300 45,200 50,000

1 No attempt was made to calculate the acres of mechanical and manual treatments for general (non-invasive) vegetation 

management. Vegetation management on BLM lands in Oregon using all methods generally exceeds 100,000 acres annually.

2 See the Assumptions and Information About Treatment Acres section in Chapter 3.
295

currently taking place. Nearly 80 percent of the expected herbicide increase between Alternatives 3 and 4, and 

75 percent of the increase between Alternatives 3 and 5, replace right-of-way, administrative site, recreation site, 

and habitat improvement projects already being done with non-herbicide methods (see negative numbers under 

Alternatives 4 and 5 above), and therefore may be neutral or even beneficial to visual resources (see Table 4-23).

The greater the area of vegetation treatment, the greater the visual impact is likely to be. The effects of treatments 

over a large portion of the landscape are more likely to be observed by people than the effects of small-scale 

treatments. However, since areas receiving large-scale treatments are most likely to be degraded lands of low 

to moderate scenic quality, the visual impact from treatment would be minimized and there would likely be an 

improvement in the scenic quality of the land over the long term.

Color contrasts caused by vegetation removal would be most apparent in areas dominated by green and/or 

flowering vegetation and by large plants, such as western juniper. The visual impacts would be heightened if 

the herbicides also prevented the manifestation of seasonal changes in vegetation, such as spring flowers and/

or fall color. However, the brown colors associated with vegetation treatments would be least noticeable during 

the late fall and the winter, when they would blend more naturally with surrounding colors, than in the spring and 

summer, when the green colors of new growth are more likely to be present. Impacts to visual resources from 

even the most broad-scale herbicide treatments would begin to disappear within one to two growing seasons 

in most landscapes. The regrowth of vegetation on the site would eliminate much of the stark appearance of a 

cleared area. Over the long term, vegetation treatments would be expected to improve visual resources on public 

lands as natural color and form are maintained and/or restored.

Effects by Alternative

Reference Analysis – No Herbicide Use

Effects of Invasive Plants: Loss of natural color and form are projected to occur on an additional 2.7 million acres 

infested with noxious weeds in 15 years when compared to the No Action Alternative (Alternative 2; see Table 

4-4 in the Noxious Weeds and Other Invasive Plants section in this Chapter).

Effects of Treatments: Potential negative effects to the visual resource that would occur under a no-herbicide 

strategy are associated with the mechanical, manual, prescribed fire, biological control, and directed livestock 

treatment methods that would be conducted. These non-herbicide methods of treatment are expected to be 

conducted on more than 20,000 acres annually. Compared to Alternative 2, this is an approximate 50 percent 

increase in these methods, but a 16,700-acre decrease in the use of herbicides, resulting in an overall increase in 

short-term negative effects.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Effects of Invasive Plants: Under this alternative, the number of infested acres partially or wholly replacing more 

visually desirable native plant communities (see Effects Common to All Alternatives, above) is projected to reach 

5.9 million acres over a 15 year period, or about 1/3 or all BLM lands in Oregon, with an annual rate of spread of 

12 percent (Table 4-4).

Effects of Treatments: Potential negative effects that would occur as a result of implementation of the No Action 

Alternative (Alternative 2) are associated with the mechanical, manual, prescribed fire, biological control, directed 

livestock, and herbicide treatment methods that would occur under this alternative. Under this alternative, 

herbicides can only be used to treat noxious weeds, and the annual herbicide treatment levels are projected to 

Final Environmental Impact Statement, Chapter 4: Visual Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 296

be 16,700 acres. The predominant visual effects of treatments are associated with the use of backpack foliar 

sprayers and hand held sprayers attached to a small tank on an ATV/UTV or truck. Only the noxious weeds in the 

treatment area would be sprayed, creating a mosaic visual effect with only the noxious weeds in the treatment area 

turning brown and dying.

The remaining herbicide acres would be treated with aerial applications (7 percent). The visual effect of 

these treatments involves the browning and die-off of larger swaths of vegetation. These types of broadcast 

applications occur where a significant portion of the area is already infested and therefore already exhibits a 

diminished visual quality. In general, herbicide treatments would have short-term negative effects (first year 

following treatment) and long-term positive effects on visual resources by allowing for the protection and/or 

return of native vegetation.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Effects of Invasive Plants: Under this alternative, the number of infested acres partially or wholly replacing more 

visually desirable native plant communities (see Effects Common to All Alternatives, above) is projected to be 1.9 

million acres less than under the No Action Alternative (Alternative 2) in 15 years, and be spreading 5 percent 

slower (7 percent versus 12 percent).

Effects of Treatments: Negative visual effects from implementation of Alternative 3 would be associated with the 

mechanical, manual, prescribed fire, biological control, directed livestock, and herbicide treatment methods that 

would occur under this alternative. Under this alternative, with the broader array of herbicides available and the 

ability to treat invasive vegetation and control pests and diseases in addition to noxious weeds, there is an increase 

in the total acres treated with herbicides when compared to Alternative 2 (30,300 acres compared to 16,700 acres). 

There is also a 7,000-acre increase in the use of prescribed fire. The mechanical treatments would be slightly less 

(3,200 acres compared to 3,500 acres) as would be the use of biocontrol methods (200 acres compared to 300). 

Both Alternatives 2 and 3 estimate the same amount of directed livestock use (2,800 acres).

Under this alternative, the use of currently available herbicides (2,4-D, dicamba, glyphosate, and picloram) would 

be reduced while other herbicides would be used. It is estimated that approximately 18,800 of the herbicide 

treatment acres would be treated using directed foliar spray (spot treatments) and cut stump/wick/wipe/hack and 

squirt methods, while 11,500 would be treated using imazapic aerially following prescribed fires or wildfires. The 

visual effect on the 18,800 acres would similar to Alternative 2, involving the browning and die-off of the noxious 

weed, invasive weed, or pest and disease host (e.g., tanoak trees in Curry County) creating a mosaic visual effect. 

This visual effect would be short-term with the long-term effect of promoting native vegetation and reducing the 

spread of the targeted species.

In those situations where imazapic is used following wildfires or prescribed fires, either a wildfire has occurred 

and the visual quality of the area has already been degraded as a result of the wildfire, or the entire area was 

already degraded by the establishment of invasive grasses and a prescribed fire was conducted. The subsequent 

application of herbicides will have no additional visual impact other than the long-term benefit of preventing the 

resurgence of invasive plants and allowing the area to return to a state where native vegetation dominates. This 

use of imazapic following wild and prescribed fires in eastern Oregon represents 85 percent of the 13,600 acres 

of increase in herbicide use between Alternative 2 (No Action), and Alternative 3. The actual increase in spot 

treatments on all other species is projected to be 2,100 net acres.

In general, herbicide treatments would have short-term negative effects (first year following treatment) and longterm positive effects on visual resources by facilitating the return of native vegetation.
297

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

Effects of Invasive Plants: Under this alternative, the number of infested acres partially or wholly replacing more 

visually desirable native plant communities (see Effects Common to All Alternatives, above) is projected to be 

2.2 million acres less than under the No Action Alternative (Alternative 2) in 15 years, and noxious weed spread 

would be reduced to an annual rate of 6 percent, or about half the current rate.

Effects of Treatments: The visual effects of Alternative 4 are associated with the mechanical, manual, prescribed 

fire, biological control, directed livestock, and herbicide treatment methods estimated to occur under this 

alternative. Under this alternative, with the broader array of herbicides available and the ability to treat invasive 

vegetation, pests and diseases, vegetation in rights-of-way, administrative sites, recreation sites, and improve 

habitats as described in Conservation Strategies, the acres treated with herbicides is estimated at 45,200 acres. 

This is a 28,400-acre increase compared to Alternative 2 (No Action). The visual effects associated with the 

treatment of noxious weeds and other invasive plants, and pests and diseases, are the same as noted under 

Alternative 3.

Under this alternative 9,300 acres of rights-of-way, administrative sites, and recreation sites would also be treated 

using herbicides. In some right-of-way areas, such as under power lines, the application of herbicides will most 

likely involve the use of a selective herbicide, which will result in a mosaic visual effect that would replace the 

visual effect of mechanically treating these areas with such things as a mower or chainsaw. Along road edges 

and around many administrative sites, a broad-spectrum pre-emergent herbicide would be used to remove most 

vegetation to prevent damage to improvements and limit the risk of wildfire encroaching on communication and 

other developed sites. In those areas where herbicides would be used in other administrative sites and recreation 

sites the primary application method would be backpack application of the herbicide to the targeted vegetation 

such as blackberry bushes, resulting in the visual effect of intermittent browned and dead vegetation in the area in 

the short term.

Under this alternative, 5,700 acres would also be used for habitat improvement projects identified in Conservation 

Strategies. For example, this type of herbicide use is proposed for treatment of western juniper and sagebrush to 

improve habitat conditions for sage grouse in eastern Oregon. Western juniper and sagebrush are currently treated 

using mechanical methods (chainsaw/mowing) to achieve these habitat objectives. All but 200 acres of these 

treatments are expected to be east of the Cascades (Table 3-3). The visual effect of these herbicide treatments 

would depend on the size of the treatment area and the application method selected, but would result in increased 

browned and dead vegetation in the short-term.

In general, the herbicide treatments proposed under this alternative would have short-term visual effects (first year 

following treatment) with the long-term visual effect of returning the treated area to one dominated by a diverse 

array of native vegetation, and preventing (or slowing) a decline in visual quality caused by future infestations.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Effects of Invasive Plants: As with Alternative 4 (Proposed Action), the number of infested acres partially or 

wholly replacing more visually desirable native plant communities (see Effects Common to All Alternatives, 

above) is projected to be 2.2 million acres less than under the No Action Alternative (Alternative 2) in 15 years, 

and noxious weed spread would be reduced to an annual rate of 6 percent.

Final Environmental Impact Statement, Chapter 4: Visual Resources
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 298

Effects of Treatments: The visual impacts of Alternative 5 are associated with the mechanical, manual, prescribed 

fire, biological control, directed livestock, and herbicide treatment methods expected to occur under the 

alternative. This alternative expands upon the use of herbicides proposed in Alternative 4 (Proposed Action) by 

4,800 acres to include treating vegetation to meet a wide range of management objectives such as treating native 

vegetation to promote habitat for elk and whitetailed deer. With the exception of this additional 4,800 acres, all 

of the visual effects for this alternative would be the same as described for Alternative 4. (Like Alternative 4, the 

mechanical, manual, prescribed fire, biological control, and directed livestock treatments are the same as those 

estimated for Alternative 3).

On the 4,800 acres where additional herbicide treatments are estimated to occur, the visual effects would depend 

on the size of the treatment area and the application method selected, but would result in increased browned 

and dead vegetation in the short-term with the long-term visual effect of creating a healthy native vegetative 

community. Some portion of these treatments would be replacing treatments currently being done with nonherbicide methods.

Wilderness and Other Special Areas

Affected Environment

In Oregon, BLM lands include Wilderness and Wilderness Study Areas; National Wild and Scenic Rivers; 

National Monuments and National Conservation Areas; National Scenic and Historic Trails; Areas of Critical 

Environmental Concern (ACEC); Research Natural Areas; and Outstanding Natural Areas. Special management 

applies within these areas, with the intent to preserve, protect, and evaluate these significant components of our 

national heritage. Most special areas are either designated by an Act of Congress or Presidential Proclamation, 

or are created under BLM administrative procedures. With the exception of Wilderness Areas and Wilderness 

Study Areas, there are no specific restrictions on vegetation treatments in these special areas. However, activities 

that have the potential to degrade the quality, character, and integrity of these lands are prohibited. The unique 

characteristics of these special areas would be considered during planning for vegetation treatment activities.

Wilderness and Wilderness Study Areas

The BLM manages eight Wilderness Areas in Oregon encompassing over 247,000 acres. The recently enacted 

Omnibus Public Land Management Act of 2009 added four new wilderness areas on BLM land, including Soda 

Mountain in the Cascade-Siskiyou National Monument, the Badlands just east of Bend, Oregon, Spring Basin 

on the John Day River, and a portion of the Lower White River Wilderness on Mt. Hood. Wilderness Areas are 

designated by Congress as areas “where the earth and its community of life are untrammeled by man, where man 

himself is a visitor who does not remain” (Wilderness Act of 1964). Consisting of areas generally 5,000 acres 

or larger, Wilderness Areas also offer outstanding opportunities for solitude or a primitive and unconfined type 

of recreation. These areas may also contain ecological, geologic, or other features that have scientific, scenic, or 

historic value. In Oregon, the BLM also manages 87 Wilderness Study Areas (WSAs) encompassing 2.6 million 

acres. While Congress considers whether to designate a WSA as permanent wilderness, the BLM manages the 

area to prevent impairment of its suitability for wilderness designation.

Vegetation treatments used in wilderness and wilderness study areas follow the guidance contained in 43 C.F.R. 

6300 (Wilderness Management; Federal Register 2000), and in the Management of Designated Wilderness Areas 
299

Final Environmental Impact Statement, Chapter 4: Wilderness and Other Special Areas

Handbook H-8560-1 (USDI 1988b), and the Interim Management Policy for Lands under Wilderness Review 

Handbook H-8550-1 (USDI 1995a). The guidance for these areas includes the following direction regarding 

noxious weeds:

• Noxious weeds may be controlled by grubbing or with herbicides when they threaten lands outside 

wilderness or are spreading within the wilderness, provided the control can be done without serious 

impacts on wilderness values and treatments are necessary to maintain the natural ecological balance.

• Plant control must be approved for native plants when needed to maintain livestock grazing operations 

where practiced prior to the designation of wilderness.

• Reseeding may be done by hand or aerial methods to restore natural vegetation.

In addition to designated wilderness and WSAs, BLM maintains inventories of public lands found to possess 

wilderness characteristics since completion of the original inventories in the late 1970s and early 1980s. To date, 

those inventory updates have found approximately 26,000 acres in western Oregon and approximately 225,000 

acres in eastern Oregon outside of designated wilderness and WSAs that meet the minimum criteria for wilderness 

character. There are no specific management restrictions associated with these areas, unless a land use plan has 

specifically allocated these areas for protection of their wilderness character. Regardless, management activities 

proposed in these areas must be analyzed for impacts to the area’s wilderness character, and reasonable mitigation 

opportunities will be considered.

Wild, Scenic, and Recreational Rivers

National Wild and Scenic Rivers (WSRs) are rivers (or river sections) designated by Congress or the Secretary 

of the Interior, under the authority of the Wild and Scenic Rivers Act of 1968, to protect and enhance remarkable 

scenic, recreational, geologic, fish and wildlife, historic, cultural, or other similar values and to preserve the 

river in its free-flowing condition. The law recognizes three classes of rivers—wild, scenic, and recreational. 

Wild rivers are free of impoundments and generally inaccessible except by trail, with watersheds or shorelines 

essentially primitive and water unpolluted. Scenic rivers are free of impoundments with shorelines or watersheds 

largely undeveloped, but accessible in places by roads. Recreational rivers are readily accessible by road or 

railroad, may have some development along their shoreline, and/or may have undergone some impoundment or 

diversion in the past. In Oregon, the BLM manages all or portions of 25 rivers totaling more than 800 miles as 

part of the National WSR System.

National Monuments

National Monuments are established by Act of Congress or by Presidential Proclamation under the authority of 

the Antiquities Act. National Conservation Areas (NCAs) are designated by Congress. Oregon BLM manages 

one National Monument (Cascade-Siskiyou National Monument) totaling nearly 54,000 acres in the Medford 

District. There are no NCAs per se on BLM-administered lands in Oregon, but the Steens Mountain Cooperative 

Management and Protection Area (428,000 acres) in the Burns District, and the Yaquina Head Outstanding 

Natural Area in the Salem District (100 acres), fall under the NCA category due to their similar Congressional 

designation origins.

National Scenic and Historic Trails

Congress, under the National Trails System Act of 1968, designates areas as National Scenic and Historic Trails. 

National Scenic Trails offer maximum outdoor recreation potential and provide enjoyment of the various qualities 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 300

(scenic, historical, natural, and cultural) of the areas through which these trails pass. National Historic Trails 

are extended trails that follow as closely as possible, on Federal land, the original trails or routes of travel with 

national historic significance. Designation identifies and protects historic routes and their historic remnants and 

artifacts for public use and enjoyment. A designated trail must meet certain criteria, including having a significant 

potential for public recreational use or interest based on historical interpretation and appreciation. In Oregon, 

BLM manages approximately 50 miles of National Scenic and Historic Trails (41 miles of the Pacific Crest 

National Scenic Trail, 8 miles of the Oregon National Historic Trail, and about 3⁄4-miles of the California National 

Historic Trail).

Areas of Critical Environmental Concern, Research Natural Areas, and 

Outstanding Natural Areas

In Oregon there are 207 ACECs totaling 826,138 acres. The BLM uses the ACEC designation to highlight 

public land areas where special management attention is necessary to protect and prevent irreparable damage to 

important historic, cultural, and scenic values; fish or wildlife resources; or other natural systems or processes. 

The ACEC designation may also be used to protect human life and safety from natural hazards. The BLM 

identifies, evaluates, and designates ACECs through its resource management planning process. Management 

prescriptions are set forth in approved RMPs and plan amendments. More detailed activity plans for ACECs may 

be prepared where circumstances warrant.

In Oregon, there are 82 Research Natural Areas (RNAs) encompassing 197,520 acres. RNAs are areas that are 

permanently protected from resource extraction and other forms of active management. They are a scientifically 

classified system of naturally occurring ecosystems for the purposes of scientific study and education and for 

protection of biological diversity. RNAs are managed to maintain the natural features for which they were 

established and to maintain natural processes.

Outstanding Natural Areas (ONAs) are areas that have unique scenic, scientific, educational, and recreational 

values. Recreation activities center on those that foster education and interpretation of the ONA’s unique 

resources. In Oregon, there are nine ONAs encompassing 17,885 acres.

Environmental Consequences

Due to the unique nature of wilderness and other special areas, limited vegetation management occurs in these 

areas. However, the BLM does control invasive and noxious weeds when they threaten lands outside the area or 

are spreading within the area itself and can be controlled. Any treatments that take place in wilderness and other 

special areas need to conform to the management prescriptions for that area and any activity that has the potential 

to degrade the quality, character, and integrity of these protected lands are prohibited. Treatment methods have 

the potential to directly and indirectly affect wilderness and other special areas such as the potential effects of 

disturbed soil (from such actions as grubbing), and the potential to affect native, non-target vegetation with the 

use of herbicides. Although it is permissible in special or emergency cases, mechanical methods of treatment are 

rarely utilized in wilderness areas due to their potential for disturbance and adherence to the principle of avoiding 

use of mechanized equipment in wilderness areas.
301

Effects Common to All Alternatives

In general, herbicide treatments in wilderness and other special areas would have short-term and usually 

negligible negative effects and long-term positive effects on wilderness and special status area values and 

surrounding areas. Regulations and planning direction governing wilderness areas and WSAs permit only 

treatments that improve the natural condition of these and surrounding areas. In Wild and Scenic Rivers, only 

treatments that protect and enhance the outstanding and remarkable values identified in the legislation establishing 

each river are permitted. Therefore, long-term effects, if treatments were successful, would be beneficial. The 

net effect of treatments on wilderness and other special areas would depend on whether the end condition of 

the treatment site (considering both long-term benefits and short-term impacts) was an improvement in the 

characteristics of the area. In almost every case (e.g., eradication of a small population of an incipient pest), 

vegetative communities in the treatment area would quickly recover, and the overall effect would be positive. In 

rare cases (e.g., repeated access to a site in order to meet off-site control objectives), the impacts of the treatment 

to the wilderness character or river values of the site could outweigh the potential long-term benefits to the special 

area. The short-term effects of vegetation treatments in other special areas would typically be less significant 

than those in wilderness areas and wild sections of WSRs, as human activities and influences are not necessarily 

incompatible with their unique qualities. However, all treatments would have the potential to alter these unique 

qualities, as well as to provide long-term benefits by controlling weeds.

With the use of herbicides, there could also be closure effects in these special areas. Access to a site treated with 

an herbicide is restricted for a few hours or days, depending on the requirements of the herbicide label. During 

site closures, BLM posts signs noting the exclusion area and the duration of the exclusion. The longer a site is 

closed, the greater the adverse effect to recreationists in terms of lost use days, particularly at sites that experience 

a higher volume of visitors.

In addition to the full range of integrated vegetation management techniques such as prevention and early 

detection common to all alternatives (see Integrated Vegetation Management in Chapter 3), the Standard 

Operating Procedures common to all alternatives help minimize the potential for adverse effects to wilderness and 

other special areas (Appendix 2).

In areas found to possess wilderness character outside of designated wilderness and WSAs, vegetation treatments 

could impair their wilderness values to varying degrees depending on the type and purpose of treatments. For 

areas with wilderness character specifically protected under a land use plan decision, effects to wilderness 

character would be similar to those effects described above for wilderness and WSAs. In other areas with 

wilderness character, treatments designed to improve ecological conditions would have impacts similar to 

protected areas, while some other treatments may more permanently affect wilderness values where treatments 

are not designed to return the area to a natural appearance. In all cases, site-specific impact analyses would be 

conducted as actual treatments are proposed, and possible mitigation measures would be considered.

Effects by Alternative

For context, and as a point of reference for assessing the potential effects of each of the alternatives, the 

approximate annual acres of noxious weeds currently being treated within each of the special area designations by 

treatment method are shown on Table 4-24. The annual acres of other invasive weeds currently being treated in 

these areas are shown on Table 4-25.

Final Environmental Impact Statement, Chapter 4: Wilderness and Other Special Areas
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 302

Reference Analysis – No Herbicide Use

The manual, mechanical, and biological treatments that would be conducted without herbicides would have 

minimal temporary adverse effects (such as soil disturbance from grubbing), and would contribute to controlling 

the spread of noxious weeds and reducing their effects on the values that the special designations are intended 

to preserve. The BLM currently treats approximately 950 acres of noxious weeds in special areas using these 

methods (Table 4-24), without compromising area objectives. Weeds within and adjacent to special areas that can 

only be effectively treated with herbicides (2/3 of the noxious weeds species, see Appendix 7: Table A7-1) are not 

likely to be eradicated with these treatments. These species would threaten the special values of these important 

areas over the long term.

It is projected that this alternative would result in an additional 2.7 million acres of BLM lands infested with 

noxious weeds in 15 years (see Table 4-4 in the Noxious Weeds and other Invasive Plants section in this Chapter) 

when compared with Alternative 2 (No Action). This additional spread would negatively affect special areas. 

This adverse effect would occur even if weed treatments were a priority in these areas, because increases in weeds 

in surrounding areas would increase the likelihood that special areas would become infested in spite of treatments.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Herbicide and non-herbicide treatments would have minimal temporary adverse effects (such as soil disturbance 

from grubbing), and have the long-term benefit of helping control the spread of noxious weeds and their effects 

on the values that the special area designations are intended to preserve. The BLM currently treats approximately 

950 acres of noxious weeds in special areas using manual, mechanical, and biological methods and approximately 

2,700 acres of noxious weeds using herbicides (Table 4-24) without compromising area objectives. These 

treatments have the long-term benefit of reducing noxious weeds within the special area and preventing them from 

spreading beyond the special area.

Under Alternative 2, the BLM is limited to the use of four active herbicide ingredients: dicamba, picloram, 

2,4-D, and glyphosate. There are 16 noxious weeds not likely to be effectively controlled under this alternative 

(Appendix 7: Table A7-1).

Table 4-24. Approximate Acres of Noxious Weeds Currently Treated Annually in Special Areas

Method Wilderness

Wilderness 

Study Areas

National 

Monuments

National 

Conservation

Areas ONAs RNAs ACECs

Wild and 

Scenic Rivers Total

Herbicides1 26 160 600 1400 180 27 74 237 2,704

Manual 12 7 50 2 175 22 34 275 577

Mechanical 130 30 105 265

Biocontrol 10 4 1 10 80 105

1

 Herbicides limited to 2,4-D, dicamba, glyphosate, and picloram

Table 4-25. Approximate Acres of Other (non-noxious) Invasive Vegetation Currently Treated Annually in

Special Areas

Method Wilderness

Wilderness 

Study Areas

National 

Monuments

National 

Conservation 

Areas ONAs RNAs ACECs

Wild and 

Scenic Rivers Total

Manual 10 25 1 21 7 64

Mechanical 5 3 5 13

Biocontrol 5 5
303

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

With a broader array of herbicides available under this alternative, the BLM would have the opportunity to 

substitute more effective and/or selective herbicides for those currently being used in special areas. This would 

result in a reduction in short-term effects to non-target species in these special areas because treatments would 

be more effective and thus less likely to need repeating, and the additional herbicides could be more selective 

and require lower quantities to be effective. This broader array of herbicides would make available herbicides 

to treat weeds that currently go untreated due to a lack of effective control. As a result, there would likely be 

an increase in acres of special areas treated under this alternative. There would be short-term effects from the 

herbicide treatments conducted under this alternative (such as the browning of the targeted vegetation) and a 

long-term benefit of better reducing the rate of weed spread within these special areas when compared with the No 

Action Alternative (Alternative 2). The ability to treat pests and diseases in State-identified control areas using 

herbicides under this Alternative is not anticipated to affect special areas unless future control areas are identified 

within or adjacent to specially designated areas. In the event this were to occur, the benefits of eradicating or 

slowing the spread of the pest or disease with an herbicide would be evaluated in the context of the values for 

which the special area was designated. At this time, the Sudden Oak Death quarantine area in southwest Oregon 

is the only identified control area in the State and has within it the North Fork Chetco River ACEC. A May 2010 

Environmental Assessment for treating Sudden Oak Death in that area with glyphosate, Applying Glyphosate 

on Tanoak to Aid in Sudden Oak Death Eradication, states that, “Glyphosate would be judiciously applied to 

facilitate the control of SOD in the ACEC. The use of glyphosate would not threaten the resource values for 

which the area was established.”

Under this alternative, the number of acres infested with noxious weeds on BLM lands in Oregon is projected 

to be 1.9 million acres less than under the No Action Alternative (Alternative 2) in 15 years, and be spreading at 

a rate of 7 percent (compared to 12 percent for the No Action Alternative). This reduced rate of spread and the 

ability to utilize herbicides that are more target-specific and require lower doses when compared to the No Action 

Alternative would result in less short-term disturbance (from both spraying and non-herbicide methods) to nontarget species, as well as increased long-term benefits to native vegetative communities in these special areas.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

The effects to wilderness and other special areas associated with the treatment of noxious weeds, invasive weeds, 

and pests and diseases are the same as noted under Alternative 3 except that treatment along roadsides and other 

developments would result in an even slower weed spread (6 percent annually, half of current rate and more acres 

protected) which will benefit all BLM administered lands, including special areas. Under Alternative 4, there 

is the additional opportunity to use herbicides to treat native and other non-invasive vegetation to achieve goals 

specified in Conservation Strategies for Federally Listed and other Special Status species and to meet safety and 

operation objectives in administrative sites, recreation sites, and rights-of-way. Should any of these treatment 

opportunities present themselves in a specially designated area, the treatment would need to be consistent with, 

and conform to, the special requirements and management objectives for that area. Therefore, treatments having 

the potential to negatively affect the unique values of the special area over the long term would be unlikely.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

The effects to wilderness and other special areas under this alternative would be essentially the same as those for 

Alternative 4 (Proposed Action) except as follows. Alternative 5 expands the opportunity to treat native and other 

non-invasive vegetation provided under Alternative 4 to include any vegetation management objective except 

livestock forage or timber production (e.g., treating native vegetation to promote native plant communities, reduce 

the risk of wildfire, and improve fish and wildlife habitat). Should any of these treatment opportunities present 

Final Environmental Impact Statement, Chapter 4: Wilderness and Other Special Areas
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themselves in a specially designated area, the treatment would need to be consistent with, and conform to, the 

special requirements and management objectives for that area. Therefore, treatments that have the potential to 

negatively affect the unique values of the special area over the long term would be unlikely. 

Recreation/Interpretive Sites

Affected Environment

Public lands in Oregon provide visitors with a wide range of recreational opportunities, including hiking, 

fishing, camping, horseback riding, hunting, cross-country skiing, boating, hang gliding, OHV driving, mountain 

biking, birding, viewing scenery, and visiting natural and cultural heritage sites. Recreation settings include 

evergreen forests, high deserts, lava flows, rugged river canyons, coastal headlands, and whitewater rapids (USDI 

2007d). Combining these natural wonders with the multitude of cultural destinations such as historic trails and 

archaeological sites makes Oregon public lands some of the most diverse and exciting in the United States (USDI 

2007d). In Fiscal Year 2007, there were 8,337,627 recreation visits to BLM public lands and waters in Oregon 

(USDI 2007d).

The presence of noxious weeds, invasive plants, and other undesirable vegetation (such as poison oak) has the 

potential to negatively affect the recreational experience of visitors to public lands. Native and other non-invasive 

vegetation also encroaches on roads, campsites, buildings, and other developments creating safety, access, and 

maintenance issues (see Administrative Sites, Roads, and Rights-of-Way section in this Chapter). At the same 

time, recreational pursuits themselves have the potential to inadvertently introduce these forms of vegetation to 

public lands. A key component of BLM’s integrated vegetation management strategy is raising public awareness 

of the threats of noxious weeds and other invasive plants and including prevention techniques on such things as 

maps, brochures, informational kiosks, and interpretive signs at trailheads. 

Following is an overview of the primary ways in which BLM classifies the recreation opportunities found on 

BLM public lands and the types of vegetation treatments associated with those classifications.

Recreation Management Categories

Dispersed Sites

The majority of BLM lands in Oregon are managed to accommodate multiple uses including many forms of dispersed 

recreation (e.g., horseback riding, hiking, nature viewing, and hunting), with basic access to these lands provided, 

and general information such as maps and brochures available, to recreationists. Visitors generally have the freedom 

of recreational choice with minimal regulatory constraints. Vegetation treatments occurring in these areas would be 

designed to meet the various vegetation objectives outlined in the Resource Management Plan for the area.

Some areas such as Wild and Scenic Rivers, parts of the National Trail System, and Wilderness Areas have 

restrictions or special emphases that may limit or focus the types of recreation taking place. Vegetation 

management in these areas is more likely to be directed at the recreation-oriented designation, and require 

selective vegetation treatments to protect visitors from hazards and/or adverse effects associated with certain 

plants in order to maintain and protect the special and unique features of the area.

Developed Sites

The other significant components of BLM’s recreation program are developed recreation sites, designated trails, 

and interpretive facilities. In Oregon, there are 30 developed campgrounds, 35 developed picnic areas, 31 
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Final Environmental Impact Statement, Chapter 4: Recreation/Interpretive Sites

developed recreation trails, 8 off-highway-vehicle (OHV) sites with staging and parking areas, 2 hang gliding 

sites, 47 “Watchable Wildlife” viewing/interpretive sites, 17 “Adventures in the Past” cultural interpretive sites, 2 

wild horse viewing sites, and 15 Backcountry Byways totaling 876 miles. The level of development varies widely 

among these different sites and designated areas, but in general, the vegetative management objectives focus on 

protecting visitors from hazards and/or adverse effects associated with certain plants and involves the control 

of noxious weeds and other invasive plants. Removal of undesirable vegetation such as poison oak to protect 

visitors, maintain the appearance and function of the site, and prevent the degradation of BLM improvements 

(such as buildings and parking lots) also takes place in developed recreation sites.

Environmental Consequences

Effective treatment of noxious weeds, invasive plants, and undesirable vegetation enhances the recreational 

experience and opportunities of public land visitors. Noxious weeds crowd out native vegetation, altering the 

natural landscape and diminishing the visual appeal of such recreational pursuits as hiking and nature viewing. 

Control of invasive plants in and around recreation sites also reduces the likelihood of their being spread to other 

sites by recreationists and their equipment.

Effects Common to All Alternatives

Effects of Invasive Plants and other Vegetation

A site that is dominated by noxious weeds would diminish the habitat for native fish and wildlife species which 

in turn diminishes the opportunities for those who enjoy such pursuits as wildlife viewing, fishing, and hunting. 

Certain types of vegetation are also injurious to humans such as yellow starthistle (noxious weed) and poison oak 

(native vegetation). The dominance and spread of noxious weeds such as Himalayan blackberry can also limit 

recreation access to such things as campgrounds, trails, and rivers. Weedy landscapes would also be aesthetically 

less pleasing, discouraging recreational use and causing recreationists to go elsewhere.

Native vegetation also encroaches on roads, developed sites, buildings, and other structures creating access, 

safety, and maintenance issues. Vegetation can destroy pavement, rub on buildings, reduce site-distances on 

access roads, and eliminate vistas.

Effects of Treatments

Control treatments for invasive and unwanted native vegetation also have an effect on recreation. For example, 

the noise associated with mechanical methods of treatment may adversely affect the recreational experience of 

a public land visitor as can closures that occur to allow the activity to take place. With the use of herbicides, 

there could also be closure effects. Access to a site treated with an herbicide is restricted for a few hours or days, 

depending on the requirements of the herbicide label. During site closures, BLM posts signs noting the exclusion 

area and the duration of the exclusion. The longer a site is closed, the greater the adverse effect to recreationists 

in terms of lost use days, particularly at sites that experience a higher volume of visitors. Dead and browned 

vegetation from herbicide treatments could also temporarily reduce recreational potential until vegetation recovered. 

Herbicide treatments could also pose some health risks to recreational users (see Human Health and Safety section). 

Unintended effects of herbicides on non-target plants, animals, and water could also affect recreation activities (e.g., 

hiking, plant collecting, hunting, and fishing). The risks to non-target species from use of the 18 herbicides are 

discussed in the Native and Other Non-Invasive Vegetation, Fish, and Wildlife Resources sections.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Overall, vegetation treatments would have short-term negative effects and long-term positive effects on 

recreation. Prevention/removal of noxious weeds and other invasive plants would maintain/return public lands to 

a more “natural” or “desirable” condition, which hikers and nature enthusiasts would likely value over degraded 

lands. In addition, the increased aesthetic value of protected or restored sites would benefit most recreational 

users. In some instances, treated sites could become more desirable as destinations for outdoor activities, making 

them more popular to recreational users. Treatment of sites to protect or restore native vegetation would enhance 

fish and wildlife habitat, to the benefit of hunters, birdwatchers, and other users of these resources. Effective 

control of unwanted native and other non-invasive vegetation within developed sites reduces building and road 

maintenance costs, and improves safety and accessibility.

Effects by Alternative

Noxious weeds and other invasive plants negatively affect all recreationists regardless of the type of recreation 

they are involved in. As noted above, negative effects range from changes in visual quality, to displacement of 

native flora and fauna, to actual human injury from nettles and other plant defenses. Noxious weeds are projected 

to continue to spread on BLM lands in Oregon under all alternatives, but the rate of spread and thus the number of 

acres infested in the next 15 years varies by alternative (Table 4-4). To the degree the alternatives would change 

that level of infestation, the negative effects to recreationists would be proportionately affected. The types and 

amount of vegetative treatments utilized under the different alternatives to address noxious weeds, invasive plants, 

and unwanted vegetation would affect recreationists and recreational opportunities on public lands.

The following discussion of recreation effects by alternative highlights the degree to which the alternatives:

• affect dispersed recreation occurring on most BLM lands; and

• affect recreation in developed recreation sites.

To provide context for this discussion, Table 4-26 provides the approximate annual acres of vegetation treated 

within developed recreation sites and hiking trails by treatment method under existing conditions (Alternative 2 –

No Action). (Currently, and under Alternative 2, the BLM can only treat officially designated noxious weeds with 

herbicides, and is limited to the use of four herbicide active ingredients: dicamba, picloram, 2,4-D and glyphosate.)

Table 4-26. Approximate Annual Acres of Vegetation Currently Treated Within Developed Recreation Sites

and Hiking Trails by Treatment Method

Method

Watchable 

Wildlife 

Viewing

Wild Horse 

Viewing

Developed 

Campgrounds

Developed 

Picnic Areas Boat Ramps

OHV Staging /

Parking Areas

Hang Gliding 

Sites

Developed 

Hiking Trails Total

Acres of Noxious Weed Treatment 

Herbicides1 1 207 8 37 30 57 340

Manual 10 360 32 17 19 1 74 513

Mechanical 22 15 13 15 1 30 96

Biocontrol 5 1 1 7

Acres of Invasive Plant Treatment 

Manual 46 23 9 7 1 54 140

Mechanical 100 4 170 21 11 10 1 33 250

Acres of Native and other Non-Invasive Vegetation Treatments 

Manual 4 45 25 9 5 1 58 147

Mechanical 2 218 10 9 6 1 32 278

1

 Herbicides limited to 2,4-D, dicamba, glyphosate, and picloram
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Reference Analysis – No Herbicide Use

Dispersed Recreation

Effects of Noxious Weeds and Other Invasive Plants: An additional 2.7 million acres of public lands are projected 

to be infested with noxious weeds when compared to the No Action Alternative (Alternative 2), and the rate 

of weed spread is estimated to be 14 percent per year instead of 12 percent, when compared to the No Action 

Alternative. As the presence of noxious weeds increases in dispersed recreation areas, their recreation potential 

decreases. Resultant adverse effects would be as described under Effects Common to All Alternatives; weedcaused reductions to fish and wildlife would diminish wildlife viewing, fishing, and hunting; weeds would limit 

access and cause injuries, and weeds would generally lower the aesthetic value of the recreational experiences – 

all proportional to the number of acres infested.

Effects of Treatments: The nearly 50 percent increase in mechanical treatments projected, when compared to the 

No Action Alternative (Alternative 2), would have the effect of such things as noise from the use of chainsaws 

and potential area closures for public safety during actual work. The effects on dispersed recreation would be 

short-term in nature. There are no anticipated short-term effects to dispersed recreation from the other forms of 

treatment available (manual, biocontrol, and livestock). Prescribed fire effects to users (smoke, area closures) 

would be less than under No Action.

Developed Recreation

Effects of Noxious Weeds and Other Invasive Plants: Without herbicides, noxious weeds would be more likely to 

infest developed sites than under the No Action Alternative (Alternative 2; Table 4-4). Further, about 2/3 of the 

noxious weeds in Oregon cannot be effectively controlled with non-herbicide methods (Appendix 7: Table A7-

1), so some weeds would not be effectively controlled at all. Either these acres would be treated using another, 

potentially less effective, form of treatment or these areas would go untreated. The resulting presence and spread 

of noxious weeds in these areas would diminish the recreation potential of the site over the long-term, and could 

lead to site closures.

Effects of Treatments - Under the Reference Analysis, most of the 340 acres of noxious weeds currently treated 

annually in developed sites with herbicides would be attempted with non-herbicide treatments, even if they 

were known to be less effective. Disturbance impacts and risks to user publics are probably lower with these 

treatments than with herbicides (in part, because herbicide uses can result in seasonal or area closures), although 

such a generality would not apply in all cases. The BLM already treats approximately 513 acres of noxious 

weeds in developed recreation sites using manual methods, approximately 96 acres using mechanical methods, 

and approximately 7 acres using biological methods (Table 4-26). The BLM also treats up to 100 acres of 

invasive plants and approximately 400 acres of native and other non-invasive vegetation (including poison oak) 

in developed sites annually with non-herbicide methods (Table 4-26). The mechanical and manual methods 

of control would result in short-term effects to recreationists (noise from the use of mechanical equipment and 

potential access restrictions while the weeds are mowed, cut, or pulled). However, most of these effects are 

happening currently, and the net effect of increasing non-herbicide treatments and decreasing herbicide treatments 

would likely be a reduction of adverse effects to user publics. (There are no anticipated short-term effects 

associated with the use of biological controls to developed recreation.)

For both dispersed and developed recreation, the lack of herbicide use eliminates any potential for accidental 

exposure to herbicides by recreationists.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Dispersed Recreation

Effects of Noxious Weeds and Other Invasive Plants - Under this alternative, the rate of weed spread would be 

expected to remain at 12 percent per year and noxious weeds are projected to infest about 1/3 of all BLM lands in 

Final Environmental Impact Statement, Chapter 4: Recreation/Interpretive Sites
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 308

Oregon in 15 years. As discussed under the Reference Analysis, the presence of noxious weeds has the potential 

to affect recreation in dispersed areas and therefore, the degree to which each alternative reduces the threat of 

noxious weeds results in a benefit to dispersed recreation activities.

Effects of Treatments - The use of herbicides under this alternative would result in temporary use restrictions 

that could affect dispersed recreation. These restrictions would typically last 24 hours but could be as long as 

one to two years to allow desirable vegetation to become established. The use of herbicides also results in dead 

and browned vegetation that might result in short-term visual impacts that adversely affect the recreational 

opportunities of a treatment area. The use of herbicides under this alternative could also result in accidental 

exposure to the herbicide by recreationists (see the Human Health and Safety section).

The effects of mechanical, manual, fire, biocontrol, and livestock treatments under this alternative are essentially 

the same as those described for the Reference Analysis.

Developed Recreation

Effects of Noxious Weeds and Other Invasive Plants - Developed sites would be affected by the current weed 

spread rate; the potential for weeds to invade developed sites would continue to increase exponentially as 

surrounding landscapes become infested. However, this alternative provides effective treatment methods for 104 

of the 120 State listed noxious weeds, so noxious weed control efforts focused on weeds in developed sites would 

generally be successful.

Effects of Treatments - Under Alternative 2 (No Action), most noxious weed control in developed recreation 

sites occurs using manual methods (approximately 513 acres). Approximately 340 acres would be treated using 

herbicides, 96 acres using mechanical methods and approximately 7 acres would be treated using biocontrols 

(Table 4-26). The mechanical and manual methods of control would result in short-term effects to recreationists 

(noise from the use of mechanical equipment and potential access restrictions while the weeds are manually 

pulled or grubbed). There are no anticipated short-term effects associated with the use of biological controls 

to developed recreation. The effects of treating noxious weeds with herbicides under this alternative includes 

temporary closure of the site or trail in accordance with the herbicide label instructions, the presence of browned 

and dead vegetation after the treatment, and the potential for accidental exposure to the herbicide by recreationists 

(see the Human Health and Safety section for more information).

Under Alternative 2, all treatment of invasive and any other unwanted native vegetation consists of manual and 

mechanical treatments (Table 4-26). The effects of these treatments would be the same as described for the 

Reference Analysis.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Dispersed Recreation

Effects of Noxious Weeds and Other Invasive Plants - Under this alternative, the rate of weed spread would 

decrease to an estimated 7 percent per year compared to 12 percent under the No Action Alternative (Alternative 

2). Under Alternative 3, 1.9 million fewer acres are projected to become infested in 15 years than under the No 

Action Alternative. As discussed for the Reference Analysis, the presence of noxious weeds has the potential 

to effect recreation in dispersed areas and therefore, the degree to which each alternative reduces the threat of 

noxious weeds results in a benefit to dispersed recreation activities. Additional benefits beyond the reduced 

spread rate include: 1) the broader array of herbicides available allows for the treatment of those noxious weeds 

that can only be effectively controlled using one of the herbicides available under this alternative and therefore 

the reduction of those weeds will improve the health and ultimately the recreation potential of those areas; and, 2) 
309

invasive (non-noxious) vegetation could be treated using herbicides. Treating some at-risk areas after a wildfire 

to prevent the establishment of invasive plants such as cheatgrass will help ensure that those areas support 

native or other non-invasive vegetation as they recover and this in turn will help those areas support recreational 

opportunities and activities.

Effects of Treatments - The effects to dispersed recreation from all methods of treatment would be essentially the 

same as described under Alternative 2 except that the additional herbicides (above the four available under the No 

Action Alternative 2) would often allow the use of an herbicide that is more target specific and generally less toxic 

to humans, and more effective in lower doses, thereby reducing the impacts of herbicide use on the recreational 

resource and reducing the chance for accidental exposure to recreationists. In addition, the use of herbicides 

to treat invasive vegetation would likely result in additional closures and additional acres of browned and dead 

vegetation, both of which could affect recreation opportunities and experiences.

Developed Recreation

Effects of Noxious Weeds and Other Invasive Plants - The effects of treating noxious weeds in developed 

recreation sites and trails would likely be very similar to effects listed under Alternative 2 (No Action) with 

several exceptions. The ability to treat another dozen of the 16 noxious weeds that cannot be effectively treated 

under the No Action Alternative could help prevent those species from adversely affecting developed recreation 

sites and trails. As with dispersed recreation under this alternative, the availability of more effective herbicides 

has the potential to improve treatment effectiveness. However, with a broader array of herbicides available, an 

herbicide may be used in place of mechanical and manual treatments if it is thought to be a more effective method 

of treating a noxious weed in the developed recreation site or trail.

Effects of Treatments - As noted under the dispersed recreation discussion, this alternative could result in the use 

of herbicides to treat invasive vegetation in developed recreation sites and trails. Currently, 140 acres of invasive 

vegetation are being treated using manual methods and 250 acres are being treated using mechanical methods in 

developed recreation sites and trails. With the opportunity to use herbicides, some of these acres would likely be 

treated using herbicides and it is also likely that additional acres, that currently go untreated due to a lack of an 

effective method, would be treated using herbicides under this alternative. The additional herbicide use would 

result in short-term recreation effects such as those associated with closures, browned vegetation, and potential 

for accidental exposure to herbicides. The availability of additional herbicides would reduce the amount needed 

(per acre), the need for retreatment, and the effects to non-target vegetation. It is anticipated that manual methods 

of treatment would continue to be the primary form of treatment of noxious weeds in recreation sites, and that the 

acres treated and the associated effects from both manual and mechanical methods would be very similar to those 

under Alternative 2 (No Action).

Native and other non-invasive vegetation encroaching on roads and other developments would continue to be 

treated using manual and mechanical methods. The effects of those treatments would be essentially the same as 

described for Alternative 2.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

The effects to both developed and dispersed recreation under Alternative 4 are very similar to those found under 

Alternative 3 with the following exceptions.

Dispersed Recreation

Alternative 4 allows for the use of herbicides to do safety and maintenance treatments of native and other 

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 310

non-invasive vegetation along access roads and around trailhead parking areas, staging areas, and similar 

developments. This would result in additional short-term closures of these areas, the presence of browned and 

dead vegetation, and an increased risk of accidental exposure to herbicides all of which potentially detract from 

the recreation experience and recreation resources. However, the long-term benefit of these additional treatments 

is an additional 1 percent reduction in the annual rate of noxious weed spread, to 6 percent, and 300,000 fewer 

acres infested in 15 years on BLM lands in Oregon when compared to Alternative 3. This gain comes in part 

because these herbicide treatments would incidentally control small, undetected noxious weeds before they are 

picked up by recreational equipment and clothing and get spread to other areas (see the Noxious Weed Spread 

Rate by Alternative subsection for Alternative 4 in the Noxious Weeds and Other invasive Plants section earlier in 

this Chapter). The maintenance of healthy, native, and diverse vegetative communities that results from this lower 

rate of weed spread benefits recreation resources over the long-term.

Unlike Alternative 3, Alternative 4 also allows for the treatment of native and other non-invasive vegetation with 

herbicides in an effort to improve habitat for Special Status species. These types of treatments could benefit 

dispersed recreation opportunities such as wildlife viewing, hiking, and hunting by promoting more natural 

conditions for plants and wildlife.

Developed Recreation

The other primary difference in recreation effects when comparing Alternatives 3 and 4 involves the option 

of treating native and other non-invasive vegetation in developed recreation sites, such as poison oak, using 

herbicides. These treatments would increase the effects of short-term area closure, the presence of browned 

and dead vegetation,67 and the risk of accidental exposure to herbicides. The ability to treat unwanted 

vegetation would result in short and long-term benefits to recreation sites and trails by improving 

access, protecting BLM improvements (signs, restrooms, parking lots), and reducing the potential for 

recreationists to be exposed to injurious native vegetation such as poison oak. With the ability to use 

herbicides to treat native and other non-invasive vegetation in developed recreation sites there would be 

a corresponding reduction in the amount of manual and mechanical treatments and therefore the effects 

from those activities would be reduced. 

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

The effects to both developed and dispersed recreation under Alternative 5 would be the same as described for 

Alternative 4 (Proposed Action) with the following exceptions.

Alternative 5 permits the use of herbicides for general habitat improvement, fuels treatments, and other nonvegetation management objectives other than those specifically for livestock forage or timber production. An 

additional 4,800 acres of herbicide treatments are expected to occur under this alternative. These types of treatments 

could have additional short-term negative impacts to dispersed recreationists from site closures, and long-term 

benefits from improved wildlife viewing, hiking, and hunting from improved conditions for plants and wildlife.

Alternative 5 also allows for the use of a slightly broader array of herbicides when compared to Alternative 

4. This would provide the BLM with greater flexibility in the treatment of noxious weeds, invasive plants, and 

unwanted vegetation and may result in different herbicides being applied in dispersed and developed recreation 

sites and trails. However, the overall acres of noxious weeds and other invasive plants treated would be about the 

same as under Alternative 4, so changes in effects to recreationists would be negligible.

67 It is also possible that treatment of native vegetation could involve such things as treating stumps of cut woody 

vegetation to keep it from sprouting. Without herbicides, the vegetation would be cut anyway, but preventing its 

resprouting would allow adjacent desirable vegetation to grow. 
311

Final Environmental Impact Statement, Chapter 4: Administrative Sites, Roads, and Rights-of-Way

Administrative Sites, Roads, and Rights-of-Way

Affected Environment

This section addresses vegetation management around administrative sites68, roads, and rights-of-way (referred 

to herein as “developments”) for the purposes of maintaining and protecting infrastructure developments and 

providing for their safe and efficient designed use. Developments addressed here include those owned and 

managed by the BLM, as well as those owned and managed by private individuals, companies, districts, city/

county/state governments, and other Federal agencies and occupying BLM lands under permit or other written 

agreement. They include but are not limited to:

• Linear utility transmission systems and pipelines, including multi-purpose corridors;

• Road or railroad rights-of-way;

• Oil and gas production or gas storage agreement areas and facilities;

• Geothermal, wind, or solar energy production areas and facilities;

• Pumped storage hydro-power production areas and facilities69;

• Common-material or rock quarry pits and storage areas (primarily to ensure invasive weeds are not spread 

with the material);

• Federal, State, local or tribal designated fire suppression equipment sites and staging areas including 

helispots;

• Cell phone, microwave, and other communication sites;

• BLM seed orchards and progeny test sites;

• Public purpose lease areas, including airstrips, schools, parks, etc. ;

• Interagency special management areas (e.g., reservoirs, military training, etc.);

• Watchable Wildlife, Adventures in the Past, Wild Horse Herd Viewing, Outstanding Natural Areas and 

other BLM designated interpretive sites;

• BLM offices, fire stations, and other facilities;

• Developed campgrounds, picnic areas, trails, overlooks, OHV play staging or parking areas, hang-gliding 

areas and boat facilities;

• Other administrative and operational sites needed for wildfire suppression, law enforcement, search and 

rescue, inventory, research, resource monitoring or other authorized administrative uses; and,

• Mines.

Vegetation is currently managed around and/or within these sites to prevent it from growing into, against, or 

through developments such as buildings, power lines, and roads; to reduce fuels so wildfire will not damage 

developments such as microwave towers and transformer stations; to reduce fuels so fires starting within the 

developments do not escape onto surrounding wildlands; to remove vegetation interfering with road sight 

distances or the safe use of developed recreation sites; and, to facilitate their designed use such culturing activities 

needed to establish, maintain, and access trees within seed orchards or progeny test sites. In general, this 

68 Administrative sites include various developed recreation sites, which are discussed in additional detail in the 

Recreation/Interpretive Sites section in this Chapter. 

69 As of July 2010, there are no approved wind, solar, or pumped storage facilities on Oregon BLM lands, but such 

projects might be developed in the future. A proposed wind energy project is under consideration on the Baker 

Resource Area.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 312

vegetation management is the responsibility of the development owner, using methods approved by the BLM. 

Permit holders are usually also responsible for controlling State Category A and T noxious weeds on their permit 

areas. Except for noxious weed control using one of the four currently approved herbicides, herbicide use is not 

currently an approved method for vegetation management in or around these sites.

Government Facilities and Roads

• The BLM operates or oversees operation of diverse facilities on public lands.70 These includeDesignated 

BLM road systems, rock quarries or pits and bulk material or equipment storage sites;

• Buildings, administrative sites and other government facilities, including leased sites and BLM (sole use) 

communication facilities, remote weather stations, water wells, etc.;

• Seed orchards and progeny test sites or cottonwood gallery production sites.

Construction and operations disturbance can often introduce noxious weeds and other invasive vegetation to 

facility sites and roads. However, most vegetation management at facilities focuses on controlling vegetation that 

can pose a health, safety, or fire hazard, contaminate materials, or interfere with site operations.

Government Roads, Quarries, Rock Pits, Bulk Material, and Equipment Storage Sites: There are approximately 

23,000 miles of BLM managed roads in Oregon including mainline, collector and administrative roads and spurs 

(USDI 2007d). All components are managed to meet transportation system objectives, including maintaining 

roadside vegetation to minimize wildfire hazards, optimize driver line-of sight for safe operations and provide 

access to various informational signs or kiosks. In addition, there are non-system roads, ways, and user-created 

access routes, which are normally not subject to routine annual maintenance. Generally, only noxious weed and 

other invasive plant management is anticipated for non-system roads.

BLM road systems require substantial quantities of “pit-run” or unprocessed rock material and crushed and graded 

rock to surface, maintain, and stabilize roads and related structures. BLM also provides nearby owners and State 

and local governments with common material to minimize overall road system management costs and increase 

efficiency and safety of travel. In some instances, material is stockpiled or pre-positioned for future use. It is 

estimated there are 300 rock pits or quarries and an additional 300 material stockpile or other road-system related 

storage sites. These sites are usually maintained free of most vegetation to enhance site operations and safety and 

to minimize the production and distribution of invasive weed seeds from the quarry, pit, or storage site to the road 

system.

Buildings, Administrative Sites, and Other Government Facilities: These include seasonal fire stations, BLM 

managed airstrips and helipads, corrals, water source developments, sanitary systems, BLM-only communication 

sites, and remote automated weather stations. Small radio repeater stations are often required to extend the “line 

of sight” for radio transmissions into remote and rugged terrain. Often these facilities are co-located with other 

BLM structures or sites managed in common with other low power communication systems owned by Rural Fire 

Districts, County Sheriffs, Oregon State Police, etc.

Recreation and Public Purpose (R&PP) Leases and Jointly Managed BLM Managed Lands: About 40 parcels 

totaling over 7,000 acres are under long-term lease or cooperative management agreements to local governments. 

These include parks, schools, solid waste transfer stations, and highway equipment maintenance or bulk materials 

storage. They also include airport buffer zones or options for future site expansion that do not require active 

vegetative management at this time. BLM also jointly manages lands with other Federal agencies, including dams 

and recreation areas around reservoirs managed with the Corps of Engineers, and training areas and radar sites 

managed with the Department of Defense. It is possible the Oregon Air National Guard, the Air Force, and some 

70 Some BLM roads and other developments not on BLM lands are also included in this discussion.
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Oregon County Sheriff’s departments have pre-identified road junctions or other suitable locations for medicalevacuation landing sites, especially in areas with frequent search and rescue operations.

Seed Orchards and Progeny Test Sites: The Oregon BLM manages four seed orchards in Clackamas, Lane, Jackson, 

and Josephine Counties. The seed orchards provide genetically improved Douglas-fir and sugar pine seed and 

seedlings for reforestation and a variety of land management activities. Additionally, the orchards are involved in 

cooperative agreements with private timber companies and nurseries to provide seed in return for commensurate 

payment for operational and management costs. All have current NEPA analysis and management plan/Record of 

Decisions (USDI 2005a, b, c, 2006a, b) with identified needs and opportunities for the use of up to five herbicides71

to control unwanted vegetation inside fenced, access-controlled, posted sites. The Forest Service Dorena Genetics 

Resource Center is also on BLM lands and has an existing NEPA document addressing the use of glyphosate and 

triclopyr (USDA 1995a). In addition there are hundreds of progeny test sites; the Forest Service manages a seed 

orchard on BLM lands in Coos County, and the Prineville District manages a cottonwood “gallery” for production of 

riparian restoration seedling production.

Rights-of-Way

Under FLPMA and the Mineral Leasing Act provisions, the BLM issues right-of-way grants to authorize the 

construction, operation, and maintenance of a wide range of projects on public lands. These include petroleum 

and natural gas pipelines, electrical transmission lines, telecommunications lines, energy development and 

distribution facilities, water facilities, (non-BLM) communication sites, and roads. Rights-of-way are issued for 

short-term use of public lands or in perpetuity. Right-of-way grants including those to the Oregon Department 

of Transportation and counties for highways generally include provisions that authorize the holder to manage 

vegetation within and adjacent to the rights-of-way using methods approved by the BLM. Provisions also 

require adherence to applicable State and Federal laws and regulations concerning the use of herbicides and other 

pesticides. Prior to the use of such substances on or near the right-of-way, grantees are required to complete a 

written plan for approval by the BLM that specifies the type and quantity of material to be used, the pest to be 

controlled, the method of application, and other information as the BLM may require. All use of such substances 

on or near the right-of-way shall be in accordance with the approved plan.

The scope and intensity of vegetation management treatments within rights-of-way are operationally specific and 

highly variable, and various vegetation management methods are used. Currently on non-BLM managed lands 

in Oregon, pre-emergence or post-emergence herbicides can be applied to prevent or control young emerging 

and existing vegetation. Mechanical methods, such as mowing, are also used on all ownerships to eliminate 

undesirable vegetation. In certain situations, livestock are used to selectively remove undesirable plant species, 

in a targeted approach. Both invasive and non-invasive vegetation can interfere with right-of-way site access and 

facility maintenance, interfere with electric power flow, and pose safety problems for workers and other users 

of the right-of-way. The development and maintenance of rights-of-way has significant impacts on vegetation. 

Maintenance of most rights-of-way in early seral vegetation exacerbates the potential for invasive plants; the 

relatively open nature of rights-of-way make them attractive to many recreationists including OHV enthusiasts, 

horseback riders, and hikers who can spread these plants within and away from the right-of-way.

Permits or memorandums of understanding (MOUs) specify expectations and responsibilities for vegetation 

management. For example, the Federal government’s 2006 MOU with Edison Electric Institute regarding its 

transmission lines specifies reducing soil erosion and water quality impacts within the right-of-way by using best 

management practices; reducing the risk to human health, natural resources, and the environment by promoting 

the use of integrated vegetation management for maintaining vegetation near transmission and distribution lines; 

manage rights-of-way to maintain habitat and protect Federally Listed species; reduce the introduction and control 

71 dicamba, glyphosate, picloram, hexazinone, and triclopyr

Final Environmental Impact Statement, Chapter 4: Administrative Sites, Roads, and Rights-of-Way
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the spread of invasive plants or noxious weeds; and, prevent wildfires (Edison Electric Institute et al. 2006). 

Vegetation management along many power line rights-of-way and other developments is addressed by existing, 

cooperatively written NEPA documents, and herbicide use proposed in those documents or their decision records 

is included on Table 3-3 for Alternatives 4 and 5.

Petroleum and Natural Gas Leases, Pipelines, Access and Related Facilities: Natural gas pipeline and associated 

underground facilities are operated and maintained in accordance with 49 C.F.R. 192, Transportation of Natural 

and other Gas by Pipeline: Minimum Federal Safety Standards, as required by the Department of Transportation. 

The only producing natural gas or petroleum field in Oregon is the Mist Field, located in Columbia and Clatsop 

Counties. This field is also used for seasonal underground storage of off-site-produced natural gas under a 

Federal gas storage agreement. Portions of major (10 inches or larger diameter) petroleum or natural gas regional 

transportation pipelines cross BLM managed lands in Oregon, and can require vegetation control on a corridor 50 

feet wide. Vegetation along the permanent pipeline right-of-way is periodically maintained by mowing or cutting. 

Vegetation maintenance is a required periodic use of the Federal lands crossed by the pipeline, and is included 

in the terms and conditions of the right-of-way grant. Generally, herbicides would not be used except for select 

treatment of nuisance vegetation or select use within aboveground facilities. No herbicides are used without 

the consent of the land-managing agency. Vegetation maintenance is conducted every 3-to-5 years, depending 

on vegetation growth rates. However, to facilitate periodic corrosion and leak surveys, a corridor not exceeding 

10 feet in width, centered over the pipeline may be maintained in an herbaceous state by annual maintenance if 

required. In addition, access routes and related facilities for monitoring, control, pumping, or compression may 

entail additional acreage. Generally, these related facilities would be fenced and devoid of any vegetation to 

reduce operational or fire safety risks. Current vegetation management, exclusive of noxious weed control, is 

limited to non-herbicide methods.

Geothermal Energy Leases, Energy Generation, and Transmission: There are no producing geothermal energy 

leases on BLM managed lands in Oregon, although there are geothermal leases primarily in Deschutes and 

Klamath Counties. Geothermal energy conversion to electric power would require on-site development of 

pipelines, generation and other facilities, electric sub-stations and transmission lines.

Railroads – Railroad rights-of-way cross BLM managed lands primarily in Baker, Deschutes, Douglas, 

Tillamook, and Union Counties. Rights-of-way also include maintenance access routes and related facilities for 

system monitoring, control, or material storage (often fenced). Generally, facilities are maintained devoid of any 

vegetation to reduce operational or fire safety risks.

Electric and Telecommunications Transmission Lines: About 4,000 miles of electric transmission lines cross 

BLM-managed lands in Oregon. Major transmission systems are considered any line energized to 69 kilovolts or 

more and are generally designated as utility corridors through BLM’s land use planning process. The interstate 

electric transmission system includes numerous lines that are operated at 230, 360, 500, or 750 kilovolts and 

require cleared rights-of way 200 feet wide and greater. Vegetation management standards are included in 

American National Standards Institute (ANSI) Standards A300-2001, Tree Care Operations – Tree, shrub and 

Other Woody Plant Maintenance – Standard Practices, and the conduct of vegetation control is covered in part by 

ANSI Z133.1-1994 for Tree Care Operations – Pruning, Trimming, Repairing, Maintaining, and Removing Trees, 

and Cutting Brush – Safety Requirements (Edison Electric Institute et al. 2006). Smaller local lines or distribution 

lines frequently cross BLM lands and are often associated with public roads and co-located with communication 

lines. Communication lines include metallic wire and fiber-optic cable telephone lines. Fiber-optic cables may be 

co-located on high-voltage towers or poles or buried in conduits parallel to power lines, railroads, or road rightsof-way. Transmission system maintenance access routes and related facilities for system monitoring, control, or 

voltage regulation or distribution sub-stations may entail additional acreage. Generally, these related facilities 

would be fenced and devoid of any vegetation to reduce operational or fire safety risks.

Communication Sites: There are about one hundred authorized communication sites on BLM managed lands in 
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Oregon, averaging about two acres per site. Some have vegetation management objectives covering as much 

as 200 acres to maintain line-of-sight for both radio and microwave technologies. Most sites are located on 

exposed ridgelines or other high topographic features and may be naturally devoid of deeper soils and taller or 

faster growing vegetation. Site maintenance access routes and related facilities for system monitoring, control 

or emergency operation fuel storage may entail additional acreage. Generally, these related facilities would be 

fenced and devoid of any vegetation to reduce operational or fire safety risks.

Renewable Wind, Solar and Hydro Energy Generation and Transmission Facilities: There are no commercial 

operating wind or solar energy facilities on BLM lands in Oregon at this time. However, the BLM’s national EIS/

Record of Decision projected a long-term wind energy lease and development potential of 9,700 acres of BLM 

managed lands, of which ten percent or approximately 970 acres could be directly affected by access roads, tower 

sites and related ancillary land uses requiring regular vegetation treatments (USDI 2005e). Oregon’s currently 

untapped solar resources are significant with two-thirds of Oregon receiving as much or more annual radiation 

than Florida. The Oregon Department of Energy’s 2005 Renewable Energy Action Plan notes 100 megawattrange solar thermal electric facilities may be the preferred option for central solar power generating facilities in 

the future (ODEQ 2005:27). A University of Oregon Solar Radiation Monitoring Laboratory 2004 Solar Resource 

GIS Data Base report shows Lake, Harney, and Malheur Counties to have the highest levels of solar radiation 

in the State (SRML 2004:1). Various other energy proposals have been made, notably pumped storage power 

generation in Klamath County, and herbicide use may be considered in related future NEPA documents.

Environmental Consequences

Effects by Alternative

West of the Cascades, up to fifty percent of rights-of-way and other developments require annual control of 

encroaching non-invasive vegetation depending upon the nature of the development and its level of use, with 

some portions of heavily used system roads getting vegetation treatment at least annually. Total non-invasive 

(native and other) vegetation control in and around administrative sites, roads, and rights-of-way is estimated 

to be 10,000 to 15,000 acres per year.72 East of the Cascades, although gross acres of developments are four to 

five times what they are west of the Cascades, the need for annual maintenance is much lower, and the annual 

vegetation control need is also estimated to be 10,000 to 15,000 acres per year.

Reference Analysis – No Herbicide Use; Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious 

Weeds Only; and, Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control 

Pests and Diseases

Under the Reference Analysis and Alternatives 2 and 3, all management of native and other non-invasive 

vegetation in and around developments would continue to be conducted using non-herbicide methods. These 

methods include mowing, flailing, tilling, roller/crushing, hoeing, scraping, pulling, prescribed fire, directed 

livestock, covering, propane (or other fuel) burning, hot foam or steam, and other methods. Objectives of these 

treatments include:

• protect developments from damage from plants such as trees growing into wires or rubbing on buildings, 

and plants growing through pavements;

• reduce flammable vegetation near developments, particularly those in remote areas such as microwave 

72 This work is so functionalized and spread across so many development owners that a more precise estimate would 

be difficult. The estimate is offered here only to provide a rough context for the Alternatives 4 and 5 proposed use of 

herbicides. 

Final Environmental Impact Statement, Chapter 4: Administrative Sites, Roads, and Rights-of-Way
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towers, to reduce the risk of damage from wildfire;

• reduce flammable vegetation along roads and around drilling and other work sites to prevent sparks and 

other ignition sources from starting a wildfire;

• remove vegetation interfering with road sight distances;

• remove vegetation interfering with safe use of developed recreation sites such as poison oak; and,

• to otherwise conduct the management the site is designed for, such as conducting culturing activities 

needed to establish, maintain, and access trees within seed orchards or progeny test sites.

Where vegetation resprouts, treatments may need to be repeated two or three times per season.

Under Alternative 2, four herbicides would be available for treating noxious weeds only. Only an incidental 

portion of the above treatments would involve noxious weeds, so the use of herbicides under Alternative 2 

would do very little to change the conduct or effectiveness of these treatments. In fact, it is common practice 

in some areas to treat noxious weeds along roadsides with herbicides, and then return to mow or otherwise treat 

the remaining vegetation on the same site. Under Alternative 3, more herbicides would be available, but their 

use would be limited to noxious weeds and other invasive plants. Along roads and around other developments 

where invasive plants such as cheatgrass create a fuels hazard, some fire protection objectives could be met with 

herbicides because invasive plants could be controlled with herbicides.

Accomplishing this work without herbicides is usually practical; it has been done at least since 1984. As 

discussed in other sections of this EIS, however, there are drawbacks when compared to herbicide use. These 

drawbacks most notably include high cost and the higher likelihood that mowing and crushing equipment would 

spread invasive plants down the road and from site to site much more so than would spray equipment. In rural 

areas, however, vegetation management along highways and county roads can be delayed or left undone because 

of the complexity of having to treat the BLM-portion of the right-of-way with non-herbicide methods. This 

results in safety issues, and having vegetation and resultant fires come right to the pavement edge where they 

cause damage.

The additional herbicides under Alternative 3 would substantially improve the ability of rights-of-way permit 

holders to meet permit requirements to control State listed Category A and T noxious weeds.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses and Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Vegetation 

Management Objectives

Alternatives 4 and 5 would make herbicides available to meet a portion of the vegetation management objectives 

in and around developments. The analysis assumes that herbicide use would replace, on a one-to-one basis, 

acres currently treated with non-herbicide methods (Chapter 3). West of the Cascades, selective herbicides are 

generally used. For example, except for a couple of feet immediately adjacent to the pavement edge73, roadside 

treatments west of the Cascades generally seek to reduce woody vegetation while maintaining roadside grasses 

and forbs in roadside drainage ditches to prevent erosion. East of the Cascades, one of several persistent preemergent herbicides may be used (Table 3-3) because the risk of erosion in the ditches is lower while the risk of 

a wildfire being started on a roadside is considerably higher, making complete clearing for 10 to 20 feet more 

desirable. Similarly, herbicides could be used to treat vegetation around wooden power poles on BLM lands, to 

reduce the risk of wildfire burning down the poles. 

73 On both sides of the Cascades, the couple of feet adjacent to pavement may be treated with persistent, bare-ground 

herbicides to prevent plants from damaging pavement edges.
317

Under these alternatives, the persistent and relatively non-selective herbicides bromacil, diuron, and tebuthiuron 

would be available east of the Cascades (and diuron would be available west of the Cascades) to provide 

longer-term vegetation control around pump stations, communications sites, electricity substations, and other 

administrative sites to protect them from wildfire. Dry vegetation near developments east of the Cascades can be 

a fire risk, and a vegetation-free buffer of even a few yards can protect these otherwise unprotected, often isolated, 

and generally unstaffed sites (see herbicide use summaries under The 18 Herbicides section in Chapter 3). Nonherbicide methods that require rock, pavement, or other materials are more expensive and can create disturbances 

that exacerbate invasive weed problems.

Herbicides would be considered where they have operational advantages over non-herbicide treatments. For 

example, vegetation under power lines west of the Cascades can be converted to shrubs and forbs by chainsaw 

cutting trees and following with stump-applied herbicide treatments to keep them from resprouting. Herbicides 

would also facilitate the removal of low-growing vegetation without the damage to compacted fills and shoulders 

that could result from blading or other treatments. As noted in the Noxious Weeds and Other Invasive Plants 

section in this Chapter, herbicides are likely to do less site disturbance, reducing the likelihood of infestation 

by invasive plants. Other potential advantages (and disadvantages) of using herbicides in rights-of-way, 

administrative sites, and recreation sites are discussed in other resource sections within this Chapter and include:

• Herbicide use would reduce mowing and other potentially more visually disturbing treatments (see Visual 

Resources section).

• Herbicide vegetation control would be less expensive than corresponding non-herbicide treatments (see

Implementation Costs section). This is particularly true for owners of pipelines, transmission lines, and 

other linear developments where the owners are already using herbicides on non-BLM portions of the 

route.

• On many sites, herbicide treatments can be safer for workers than the corresponding use of mechanical 

equipment like repeated use of chainsaws (see Human Health and Safety section).

• Herbicide use on native and other non-invasive vegetation would incidentally kill noxious weeds not 

identified and controlled by noxious weed control crews, which is particularly important because roads are 

dispersal corridors for noxious weeds, and access roads under power lines often attract OHV use, which is 

implicated in noxious weed spread (see Noxious Weeds and Other Invasive Plants section). 

• Because OHVs use power line and other access roads, herbicide exposure could increase for this user 

group.

• Herbicide equipment would be less likely to move noxious weed seeds to other sites than other control 

methods (see Noxious Weeds and Other Invasive Plants section). These last two points are projected 

to incidentally74 reduce noxious weed infestations by 300,000 acres over 15 years when compared to 

Alternative 3.

• Herbicides would be less likely to start fires than most mechanical control treatments, particularly 

chainsaws.

• Herbicides could be used by cooperators to maintain sight-distances on shared maintenance roads in 

checkerboard lands, allowing safety-related maintenance of entire haul routes in a single treatment and 

better facilitating cooperators’ expected heavy use dates. 

• Keep wildfire away from developments (also see Fire and Fuels).

The potential for positive and negative effects to soils, wildlife, water, wetlands and riparian areas, human health, 

public perception (socioeconomic), and native and other non-invasive plants are discussed in those sections. For 

example, roadsides include ditches and culverts that lead to streams. The potential for roadside sprays to enter 

those streams is considered in the Water Resources section. Similarly, the general application of herbicides to 

74 Incidentally, because noxious weed control is not the stated objective of the native vegetation control treatments that 

would take place under Alternatives 4 and 5.

Final Environmental Impact Statement, Chapter 4: Administrative Sites, Roads, and Rights-of-Way
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 318

roadsides is considered by many publics to result in an unknown and unacceptable potential exposure to humans 

(see Social and Economic Values and Human Health and Safety sections).

Standard Operating Procedures, site-specific NEPA analysis, licensed applicators, and other restrictions would 

apply to all herbicide applications. For example, herbicides are usually not applied aerially over power lines 

because drift could not be adequately controlled while flying that high (although they may be applied by flying 

under power lines). In addition, stream and Special Status species’ buffers suggested in the PEIS Mitigation 

Measures and finalized at the project level must be adhered to. Herbicide use in and around developments 

including those occupying BLM lands under permit or other agreement is subject to BLM approval.

Seed Orchards and Progeny Test Sites: Herbicide use at the Horning, Tyrrell, Provolt, and Sprague Seed Orchards 

was proposed and examined in detail in a 2005 Integrated Pest Management EIS, and that use was subsequently 

approved in December 2005/2006 Records of Decision pending the lifting of the 1984/87 District Court Injunction. 

Five herbicides75 are proposed to be used in combination with non-herbicide methods for the control of noxious 

weeds, woody brush, and other vegetation along fence lines, roads, administrative buildings, buffer areas, 

competing vegetation around orchard trees, and for site preparation when establishing new seedlings. Herbicides 

would replace some of the work currently done with non-herbicide methods. For example, manual vegetation 

control along fence lines at the Tyrrell Seed Orchard is currently scheduled about every three years, and requires 

about 21 days for a 10-person inmate crew to complete. An herbicide application covering the area would take 

one person a single day. These alternatives also include the use of glyphosate and triclopyr (as well as future siteevaluated herbicides) at the Forest Service Dorena Genetic Resource Center for noxious weeds, woody brush and 

vegetation along fence lines, roads and administrative buildings, and competing vegetation around orchard trees. 

The cottonwood gallery site at Prineville may need incidental herbicide use for vegetation maintenance.

In general, herbicides are not required for vegetation control on the hundreds of first generation progeny sites; 

measurements are nearly completed and most are being managed as part of the surrounding forestland. However, 

Salem and Eugene BLM each have a 10-acre second-generation Douglas-fir site planted in 2001, and Coos Bay 

BLM has two 13-acre Douglas-fir sites planted in 2002. Control of selected brush and weed species on the Salem 

and Eugene sites may be beneficial for maintenance, but only minimal herbicide use is planned. Herbicides are 

not expected to be required on the Coos Bay sites. Proposed herbicide use in seed orchards and progeny sites 

totaling about 100 acres per year is included on Table 3-3, and the potential for adverse effects to water and other 

resources is addressed in those sections of this EIS.

Social and Economic Values

Affected Environment

Use of resources and recreational visitation on BLM lands generates employment and income in the surrounding 

communities and counties. Revenues generated from these uses are returned to the counties and Federal treasury, 

or are used to fund additional activities to accomplish land management objectives. Similarly, resources flowing 

from BLM lands including water, fish, wildlife, and clean air affect surrounding communities and off-site 

resources. Additionally, less desirable elements like wildfire and invasive weeds can also affect surrounding 

communities. Herbicide use and other vegetation treatment methods on BLM lands affect these area resources 

and opportunities, and thus affect the adjacent communities.

75 dicamba, glyphosate, picloram, hexazinone, and triclopyr
319

Final Environmental Impact Statement, Chapter 4: Social and Economic Values

Analysis Area

For this analysis, four economic areas from the U.S. Bureau of Economic Analysis (BEA)76 are used to divide 

the State into two broad areas composed of counties that fall on the east and west sides of the Cascade mountain 

range. Social and economic characteristics of Oregon make this division appropriate. The Interior Columbia 

Basin Ecosystem Management Project (ICBEMP) used the BEA’s economic areas for regional analysis (USDA 

1998). These economic areas represent the relevant regional markets for labor, products, and information and 

are mainly determined by commuting patterns. This delineates local labor markets and serves as a proxy for 

local markets where businesses in the areas sell their products (Johnson and Kort 2004). Four of these economic 

areas make up most of Oregon: west of the Cascades the Portland-Vancouver and Eugene-Springfield economic 

areas, and the Bend-Prineville and Pendleton-Hermiston economic areas are located east of the Cascades. 

While Curry, Klamath and Malheur counties make up portions of other economic areas, they can reasonably be 

considered as integrated with adjacent economic areas in Oregon for this analysis. Two analysis areas, one for 

each side of the cascades, logically combine economic areas, correspond to district boundaries, and separate areas 

with significantly different ecological settings, issues, and primary resource management objectives. Scoping 

comments, population density differences, and other factors also make this grouping appropriate from a social 

perspective.

In the western half of the State, residents are likely to identify and place value in a variety of traditions, cultures, 

and ways-of-life within both urban and rural areas. Communities in the growing urban centers of the Willamette 

Valley and SW Oregon value public land for recreational, commodity, and non-commodity uses. Outside of these 

urban areas agricultural traditions are valued and a part of the culture of many Oregonians. In more rural areas 

of the Cascade Mountain foothills, the Coast Range and along the coast, timber, and fishing traditions are valued 

culturally.

In the eastern half of the State, residents also identify and place value in a variety of traditions, cultures, and 

ways-of-life within the growing urban areas and steadfast rural communities. Along the Columbia Plateau 

residents identify with farming traditions more than grazing or timber. In the Northeastern portion of the State, 

residents are outdoor-oriented in work and play which remains a key value in local communities and an amenity 

that attracts newcomers. Grazing and timber traditions are also a source of cultural identity in this area (JKA

2006). As noted above, pockets of growing urban areas also exist throughout Oregon’s east side where residents 

identify and place value in a variety of cultures. Regardless of whether a community is west or east side or can be 

classified as urban or rural, Oregonians value natural resources and the outdoors at some level. Whether through 

traditional industry, recreation, or with a preservation ethic, communities see the landscape as an important part of 

what it means to be an Oregonian.

Population and Demographic Change

In 2005, the State of Oregon had a total population of 3,629,959 people with 3,148,960 (85 percent) and 480,999 

(15 percent) west and east of the Cascades respectively. Population growth from 1970 to 2005 on both sides of 

the Cascades was faster than the 45 percent national average. Over this period, the State population grew by 72.4 

percent west of the Cascades and 75.7 percent east of the Cascades (Figure 4-8).

Oregon had an overall population density of 38 people per square mile in 2005. Population density within Oregon 

varies widely, with the lowest county population density at 0.7 people per square mile in Harney County and the 

highest county population density at 1,560 people per square mile in Multnomah County.

76 The Bureau of Economic Analysis (BEA) is an agency in the United States Department of Commerce that provides 

important economic statistics including the gross domestic product of the United States. Its stated mission is to 

“promote a better understanding of the U.S. economy by providing the most timely, relevant, and accurate economic 

data in an objective and cost-effective manner.”
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Figure 4-8. Population change for Oregon and counties east and west of the Cascades (Source: US

Department of Commerce 2005)

Population density does not indicate if the people living in the area are in more urban or rural areas. The U.S. 

Census Bureau classifies urban areas and their populations. In the year 2000, populations in counties west of 

the Cascades were 82 percent urban and 18 percent rural. Of the 82 percent, 65 percent were classified as being 

inside urban areas while the remaining 17 percent were inside urban clusters (census blocks that have a population 

density of at least 1,000 people per square mile and surrounding census blocks have an overall density of at least 

500 people per square mile), demonstrating a predominantly urban population.

East of the Cascades, populations were 58 percent urban and 42 percent rural. Of the 58 percent classified as 

urban only 13 percent were actually classified as being inside urban areas while the remaining 45 percent were 

inside urban clusters, demonstrating the east side contains pockets of urban populations (US Census Bureau 

2000a) across a predominantly rural landscape.

Economic Specialization

It is expected that communities that are particularly dependent on a single, resource-dependent industry would 

be more susceptible to the differences between the alternatives than other communities. In particular, ranching 

and recreation-dependent communities may be more affected than more diversified communities. Rural county 

population change, the development of rural recreation, and the development of retirement-destination areas are 

all related to natural amenities (Knapp and Graves 1989, Clark and Hunter 1992, Treyz et al. 1993, Mueser and 

Graves 1995, McGranahan 1999, Lewis et al. 2002). Many of the natural amenities in the area are managed by 

the BLM and thus, may indirectly contribute to specialization in rural areas. For example, elk hunting on BLM 

lands in the fall provides a significant injection of external dollars in some rural areas of Oregon.
321

Perceptions, Values, and Concerns

Oregonians’ awareness of the threat posed by invasive species to the landscape, and consequently to their values 

traditions, cultures, and ways-of-life, is increasing. Scoping for this EIS indicated a broad level of support for 

controlling invasive species on public lands. In 2002, the Oregon Invasive Species Council was created by the 

State Legislature and began working to raise public awareness of Oregon’s invasive species. One of the actions 

taken by the council was the creation of a hotline to ensure that the public could help in reporting of new exotics 

and invasive plants. Since its inception, the number of calls has increased each year (Statesman Journal 2007) 

indicating a potential increase in awareness and community engagement.

The effects of Federal land management actions are likely to be most critical to small, rural communities (USDA 

2000a:5). Consequently, geographically defined communities are an important and relevant level for social 

assessment. Not all social scientists agree however, that the geographically based community is always the 

appropriate level of analysis. FEMAT (USDA et al. 1993:VII-35) makes the point that this view “only refers to 

physical or political boundaries and not to the relationships among people who reside within such boundaries.”

Communities of interest transcend physical or political boundaries and can be used to examine effects to 

rural communities. Communities of interest bring together stakeholders from different backgrounds to solve 

problems of common concern (Fischer 2001:4). Brown and Duguid (1991) describe communities of interest as 

“communities-of-communities.” They provide unique opportunities to explore the linkages between people and 

public land that may transcend the geographically defined community. 

The Environmental Consequences section identifies scoping-defined groupings based on perceptions, values, and 

concerns that address both communities of place and communities of interest as they relate to the alternatives.

Environmental Consequences

Invasive plants affect BLM and surrounding lands in a variety of negative ways. Infestations can reduce 

recreational land values, and the spiny species can cause human health problems (DiTomaso 2000). For 

example, hunters and bird dogs are reluctant to use land infested with thistles, and weeds diminish the enjoyment 

of recreationists along trails and near campgrounds. Float boaters similarly have difficulty finding suitable 

campsites, and fishing along stream banks is often impossible because of the pain inflicted by thistles (Asher 

and Spurrier 1998). Invasive plants can have a negative effect on observation-based tourism, as the wildlife and 

wildflowers that people come to enjoy and photograph are crowded out by invasive plants (Westbrooks 1998). 

Consequently, recreation dependent communities in Oregon may be more susceptible to the effects of invasive 

weed spread than more economically diversified communities.

Similarly, the Livestock section in this Chapter identifies reductions in livestock carrying capacity of thirty-five to 

ninety percent from weed infestations. Invasive weeds affect the livestock industry by lowering yield and quality 

of forage, poisoning animals, increasing the costs of managing and producing livestock, and reducing land value 

(DiTomaso 2000). A 1993 economic study in Grant County showed the annual economic impact to livestock 

grazing was $326,000 and losses would climb to over $3.96 million [2009 dollars] without increased weed 

management (Test 1993). In addition to impacts on forage for livestock, invasive plants have impacts on other 

commodity uses of BLM lands. West of the Cascades, scotch broom partially hampers reforestation efforts and 

reduces growth rates of surviving trees on some timber harvest units (Asher and Spurrier 1998).

Management of invasive plants affects the goods, services, and uses provided by BLM lands. The analysis 

of social and economic effects considers market and non-market related values as well as effects to program 

Final Environmental Impact Statement, Chapter 4: Social and Economic Values
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 322

areas and users of public lands. Direct and indirect effects to programs and BLM users are examined for each 

alternative in the context of community perceptions, values, and concerns.

Concerns Raised During Oregon Scoping

Many if not most of the comments received during the scoping period for this EIS in July 2008 reflect the 

perceptions, values and concerns of individuals, geographic communities, and communities of interest throughout 

Oregon. People’s feelings and ideas about herbicides are complex. The variety and detail of scoping comments 

is summarized here into three general categories that are subsequently examined across the range of alternatives. 

The categories are not intended to label individuals as the comments from single individuals often fell into more 

than one of these categories.

The Spread of Invasive Plants from Adjacent BLM Lands

Scoping comments described adverse effects from the spread of invasive plants from BLM to adjacent lands. 

Comments suggested BLM’s fragmented ownership pattern and large number of acres (more than 75 percent of 

some counties east of the Cascades) creates more edge and greater potential for invasive plants spread onto private, 

residential, urban, agricultural, or other land uses. The inability of BLM to effectively control numerous specific 

weed species such as medusahead and perennial pepperweed jeopardizes cooperative weed management efforts, as 

other partners are using herbicides that are more recently available. This was the most frequent comment raised east 

of the Cascades. 

Concerns over the spread of invasive weeds from BLM lands are often founded in the reality of economic losses 

seen in communities often close to BLM lands. In 1988, a 1,300-acre ranch in Klamath County was abandoned 

and then auctioned for about ten percent of its original value due to a leafy spurge infestation (Asher and Spurrier 

1998). Incomes in ranching dependent communities are also affected by weed spread since weeds decrease the 

nutritional value and availability of forage in pastures. These effects are compounded by increasing commodity 

prices, which further decrease profitability. Production losses, fire damage and control costs associated with 21 

invasive plants in Oregon were estimated at $120 million per year in 2007 dollars. Potential nursery production 

losses and control costs if Sudden Oak Death continues to spread in Oregon were estimated at $79 to $304 million 

per year in 2007 dollars. In addition, the complete removal of invasive plants and revegetation with native species 

in the city of Portland was estimated at $10 to $31 million per year in 2007 dollars (Cusack and Harte 2008). 

While total costs attributable to invasive plant spread from BLM lands are not available, these examples give 

perspective on the extent of potential losses statewide. Costs from noxious weed and other invasive plant spread 

from BLM lands would be borne by communities and landowners adjacent to BLM.

Herbicide as a Threat to Resource Values and Human Health

Many comments proposed that the potential damage to resource values from treatments does not justify the use 

of herbicides. Many suggested herbicides threaten non-target native, Federally Listed, and other Special Status 

species. Some noted effects to other forest products collected for their subsistence, cultural or commercial value 

such as chanterelle or matsutake mushrooms. Others suggested herbicides would destroy beneficial species which 

help control invasive plants. Concerns about the persistence of herbicides in soils and their threat to air and water 

quality were noted. Particular concern was expressed about bioaccumulation and the threat herbicides pose to 

biodiversity and ecosystem function. Several comments identified threats to resource values off BLM lands 

from off-site movement of herbicides; agricultural crops and other non-target species were mentioned. Other 

comments made the case that the use of aerial application and boom broadcast spraying methods increased the 

likelihood of harm to these resource values. Many of these comments reflect the interests of communities who 

value non-commodity uses of BLM.
323

In addition to concerns about adverse ecosystem effects of herbicides, comments reflected concerns about adverse 

effects on human health. These comments noted the increased human health threat to users of BLM lands, 

adjacent landowners, herbicide applicators, and BLM personnel who work in the field. Particular comments 

made the case aerial application and boom broadcast spraying methods were a threat to human health. Other 

comments noted that children, elderly, and others with special medical conditions have an increased vulnerability 

to herbicide treatment. Bioaccumulation and cumulative exposure to pesticides and other contaminants from all 

sources was stated as a concern.

Herbicide as a Benefit to Resource Values

Many comments stated that proper herbicide use could enhance, protect, and maintain resource values. These 

comments made the case that herbicides can be used to maintain and restore habitats and biodiversity on BLM lands, 

including in special management areas. Others said herbicide treatments would decrease the threat of noxious weeds 

and other invasive plants to commodity and human uses such as livestock grazing recreation use. Others stated 

that additional herbicides, and aerial application methods, are essential to ensure efficient and effective treatment of 

invasive plants and allow BLM to enhance, protect, and maintain resource values at lower cost.

These and related comments identified a range of commodity and non-commodity resource values important to 

quality of life that need to be protected. They noted that assigning and understanding the value of non-commodity 

resources and non-market values was important, since without estimates, these resources may be undervalued 

and decisions regarding their use may not accurately reflect their true value to society. Non-market values can be 

particularly difficult to quantify because they include existence, bequest, and option values. Existence values are 

the amount society is willing to pay to guarantee that an asset simply exists, while option and bequest values are 

society’s willingness to pay to preserve the opportunity for future use and for future generations

In their report to the Oregon Invasive Species Council, Cusack and Harte (2008) note that while there have been 

many studies on the impacts of invasive species in localized settings, few take into account non-use impacts of 

invasive species, which might be due to the difficulty in preparing estimates and the controversy over available 

methods. In the absence of quantitative information for these goods, they are discussed qualitatively where 

appropriate below. These values are also discussed in other sections of this EIS.

Effects Common to All Alternatives

Invasive weeds on BLM lands and the activities proposed under the alternatives can affect the public in several 

different ways including:

• Management activities such as those involving timber, vegetation, public access, grazing, recreation, 

mining, fire, and fuels management are made more expensive by the need to incorporate weed prevention 

techniques such as equipment cleaning, avoidance, seasonal restrictions, mitigation, and monitoring;

• Physical and aesthetic impediments to land use created by the invasive plants themselves;

• Area or facility closures, or herbicide exposures, related to vegetation treatments themselves;

• Degradation of resources flowing from BLM lands such as water or wildlife;

• The spread of invasive weeds to non-BLM lands; and,

• Infestation-related resource displacement resulting in commodity, non-commodity, and non-market losses.

Conversely, treatments under the action alternatives would variously result in improvements in the condition 

of BLM resources and would lead to increases in commodity, non-commodity, and non-market values. 

Non-market values such as improved recreation opportunities, reductions in wildfire risk, more efficient 

Final Environmental Impact Statement, Chapter 4: Social and Economic Values
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 324

management of rights-of-way, and habitat improvements would benefit the economies of communities, 

dependent on recreational opportunities and natural amenities.

Economic Losses

Economic losses are not particularly quantifiable for BLM lands with existing information. BLM lands share a 

statewide problem that no central source exists for compiling invasive plant infestation and treatment information 

within Oregon, and there is no requirement for county, private, or corporate landowners to report invasive plant 

information Despite limited reporting on weed locations, maps of the reported distribution of noxious weed 

species are available on a species-by-species basis online at http://www.weedmapper.org. The 1.2 million acre 

estimate for noxious weeds was compiled by the nine BLM district weed coordinators based on district maps and 

records, and from a special report, and includes about 600,000 acres just of medusahead.

Oregon-wide information compiled for the Oregon Department of Agriculture by Radke and Davis (2000) 

is illustrative of the issues on BLM lands, since BLM manages 25 percent of Oregon and 12.3 percent of its 

forestlands. Their report includes:

“A preliminary analysis of the economic impact in personal income of the 12 worst noxious weeds in 

Oregon estimated the foregone income to Oregon of these weeds to be $67 million annually (Radtke 

1999)”,

And

 “In Oregon... tansy ragwort, is known to have caused annual losses on the order of $6 million. 

Economic Containment programs so far have kept tansy ragwort from becoming an economic problem in 

eastern Oregon. There is a real threat for this noxious weed to expand into rangelands of eastern Oregon. 

The potential loss to agriculture and supporting industries for such on invasion could be $10 million in 

total personal income or 400 annual jobs.”

Effects by Alternative

The Spread of Invasive Plants from Adjacent BLM Lands

Neighboring private and public lands are adversely affected by the spread of invasive plants from BLM lands. 

Land values are reduced, forage and other vegetation values are harmed, and weed control costs for neighboring 

landowners or other administrative agencies (Federal, State, and local governments) are increasing. A reduction 

in the magnitude of these adverse effects would be directly related to the success of the selected alternative in 

slowing noxious weed spread and decreasing future infested acres.

Reference Analysis – No Herbicide Use: The spread of invasive plants from BLM lands would be highest under 

without herbicides, where weed spread would increase to a predicted 14 percent annually, and an estimated 1/2 

of BLM lands in Oregon would be infested with noxious weeds in 15 years (Table 4-4). Further, the BLM would 

be without effective control methods for about 2/3 of the noxious weed in Oregon (Appendix 7: Table A7-1), so 

eradication of specific weed populations about to spread to new or susceptible areas would often be ineffective.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only: Under Alternative 2, noxious weeds 

would be expected to continue expanding at the current 12 percent per year, and about 1/3 of the 15.7 million 

BLM acres in Oregon are projected to become infested in 15 years (Table 4-4). Since treatment acres would 

remain at current levels, future costs to neighboring private and public lands would continue to escalate along 

current trends as the scope and size of the problem continued to grow.
325

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases: 

Under Alternative 3, future costs to neighboring private and public lands would decrease (from the No Action 

Alternative). Herbicides would be available to treat 97 percent of the noxious weeds, and cooperative control 

efforts could take place on BLM lands because most of the herbicides already being used by these groups on 

adjacent lands would be available. The BLM would be perceived as a more equal partner in weed control efforts 

with the means to use a wider range of herbicides. In addition, some east side and possibly Siskiyou Biome 

communities would benefit from decreased fire risk associated with additional treatments with imazapic to reduce 

annual grasses. Wildland fire-related costs in these communities (such as property loss, and lost revenues) could 

be reduced because of the additional 11 to 13,000 acres of invasive grass treatments east of the Cascades.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses and Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation 

Management Objectives: Under Alternatives 4 and 5, neighboring private, residential, urban, and other land uses 

adjacent to BLM lands would benefit from the overall reduction in noxious weeds of 2.2 million acres in 15 years 

when compared to the No Action Alternative (Table 4-4). Benefits to adjacent landowners would particularly 

accrue from the roadside herbicide treatments indirectly reducing noxious weeds and other and invasive plants in 

locations where they are most likely to be spread to their lands.

Herbicide as a Threat to Resource Values and Human Health

Many comments stated invasive plant control did not justify the adverse effects to non-target plants, wildlife, 

water quality and other resources values from herbicide treatment. Particular concern was expressed about the 

use of methods such as aerial application and boom broadcast spraying methods. This perception would be least 

under Alternative 2 (No Action) and to some degree 3, because herbicide use would be limited to the control 

of invasive plants. A certain segment of the comments expressed concerns that herbicides would unacceptably 

damage non-target plants and other non-commodity resources and non-market values. Alternative 2 may be more 

acceptable because of the fewer acres treated with herbicides (Table 3-3), but Alternative 3 would use 35 percent 

fewer total pounds (Table 3-4) and provide more herbicides to accomplish control objectives while decreasing 

environmental risk.

A related concern is potential threats to human health from herbicide use and its method of application. In 

addition to users of BLM lands and resources, comments identified applicators as being among those most likely 

to be exposed to herbicides. Concerns were not limited to exposure from direct application; concerns have been 

expressed over the potential for accumulation and cumulative effects, and from contamination of ground and 

surface waters that are used for consumption. Because concerns about herbicide effects on the environment and 

human health are primarily tied to the acres of use, concern is likely to remain lower under Alternative 2, the No 

Action Alternative than under any of the action alternatives.

Under Alternative 3, concerns about the use of herbicides would likely intensify because of an 81 percent 

increase in projected herbicide treatment acres, an increase in the number of herbicides available, and the 

addition of non-noxious invasive plants to the list of species that could be sprayed. However, while an 81 

percent overall increase over the No Action Alternative (Alternative 2) is projected, concerns may be limited 

because only a 14 percent increase is anticipated west of the Cascades where population densities are the 

greatest. Increased use west of the Cascades is limited by a slightly lower incidence of invasive plants, a lower 

incidence of the invasive annual grasses that account for most of the increase east of the Cascades, by the 

presence of more (and often difficult to detect) watercourses, by topography, and by population densities and 

public concerns. The 14 percent acreage increase would be considered by a portion of this concern group as 

worthwhile because it would control additional weed species and Sudden Oak Death, because total pounds of 

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herbicide to be applied would decrease 35 percent, and because there would be no aerial applications permitted 

west of the Cascades. As with Alternative 2, Standard Operating Procedures and PEIS Mitigation Measures 

would limit risks to human health and wildland resources.

The Human Health and Safety section in this Chapter concludes that the additional herbicides available under 

Alternative 3, on average and in total, present less risk to human health than the four currently used herbicides. 

Use of 2,4-D is projected to decrease by 2/3 compared with Alternative 2. Despite the adoption of Standard 

Operating Procedures and PEIS Mitigation Measures, the decreased risk associated with the additional herbicides, 

and the 35 percent reduction in pounds applied, perceived risk to human health would remain and likely be greater 

than under the No Action Alternative (Alternative 2) because 13,600 more acres would be treated.

Under Alternative 4 (Proposed Action), concerns about resource damage and human health risk from the use of 

herbicides are likely to intensify significantly with the addition of herbicides to annually treat nearly 15,000 acres 

of native and other non-invasive vegetation along rights-of-ways, administrative sites, recreation sites, and certain 

habitats. Public comments reflected concern that herbicide treatments along roadsides could have unintended 

consequences on human health and non-target food or water sources. Comments expressed concern that they 

would be unknowingly exposed by traveling on BLM roads and utilizing roadside resources. They also point out 

that this work is taking place now simply at higher cost. Aside from using herbicides at all, spraying roadsides 

is probably the biggest concern with this group. This alternative is rated in the Human Health and Safety section 

in this Chapter as having a slightly higher potential for health risks than Alternative 3. Thus, perceptions of 

herbicide as a threat to resource values, human health, and quality of life would remain and likely intensify given 

the availability of additional herbicides and treatment of 14,900 additional acres when compared with Alternative 

3 (Table 3-3).

Under Alternative 5, concerns about resource damage and human health risks from the use of herbicides would 

be greater than under Alternative 4 (Proposed Action) because the additional 4,800 acres of projected use is more 

open-ended in terms of its objective, need, and location. Further, 50,000 total acres of herbicide use annually will 

simply seem too high for many people in this group, regardless of the objective. It is nearly three times the No 

Action Alternative (Alternative 2) and nearly four times use levels in recent years. This alternative would also 

permit aerial applications west of the Cascades, although such use would be rare (something less than one project 

annually). Finally, this alternative would raise the number of herbicides available to 18, although actual treatment 

acres for some of the additional herbicides would be low.

It would help those with concerns about Alternative 5 that most of the increased use (when compared to 

Alternative 4) would be east of the Cascades, and that most would likely be for additional habitat treatments 

such as the reduction of rabbitbrush and western juniper currently at unnaturally high levels because of years of 

fire exclusion. These individuals and groups will also be eased by the fact that the 18 herbicides that would be 

available under this alternative have been analyzed and chosen by the BLM nationally as those with the least 

risk to humans and the environment and most appropriate for BLM wildland use, from among over a hundred 

herbicides registered for use in Oregon. These herbicides, and this alternative, are what is currently available to 

BLM in the other 16 western states. Nevertheless, the potential for adverse effects to human health and wildland 

resources could be perceived as greater under Alternative 5 than for the other alternatives. The analysis in this 

EIS judged this alternative to have the greatest overall risk to human health of the alternatives in this EIS, thus 

the perceptions of herbicide as a threat to resource values and human health would be the greatest under this 

alternative, with its availability of additional herbicides, additional management objectives, and 4,800 additional 

acres treated.
327

Herbicide as a Benefit to Resource Values

Reference Analysis: Many comments stated that proper herbicide use could enhance, protect, and maintain 

resource values. While effective invasive plant control without herbicide use could be maintained in some areas, 

the 14 percent noxious weed spread rate and 8.6 million acres infested in 15 years would be perceived as more 

adverse than the other alternatives by these stakeholders. Those who hold commodity, non-commodity, and 

non-market values of BLM lands and perceive herbicide use as an effective means to protect these values would 

be troubled by accelerated decline in resource conditions and biodiversity as a result of increases in the rate of 

spread. Given the largest costs per acre of treatment (Implementation Costs section) and the labor-intensive 

nature of limited treatment options, individuals and groups interested in reducing costs to protect resource values 

would likely perceive reduced treatment effectiveness as an inefficient means of controlling invasive plants.

Alternative 2, the No Action Alternative, would be perceived as an improvement over the Reference Analysis. 

However, many stakeholders would perceive the current spread of noxious weeds and other invasive plants as an 

adverse effect. Since more effective controls are available to other agencies and landowners in Oregon and even 

to BLM in the other 16 western states. Those who hold value commodity, non-commodity, and non-market values 

of BLM lands and perceive herbicide use as an effective means to maintain those values, would see the continued, 

and to them unnecessary, decline in resource conditions and biodiversity as an inappropriate way to manage the 

BLM’s public resources.

Alternative 3 would be perceived as a substantial improvement to those seeing herbicides as an efficient and 

effective way to benefit resource values. Additional herbicide treatments of noxious weeds and other invasive 

plants under this alternative would be perceived as improving ecosystem health, thus improving the quality of 

market and non-market values. In addition to reducing weed infestation by an estimated 1.9 million acres in 15 

years, unquantifiable benefits would accrue from being able to treat weeds as aggressively as adjacent landowners. 

Important native species and biological diversity within scenic areas, scenic byways, wild and scenic rivers, 

wilderness areas, and ACECs would be better maintained; recreation and/or educational values of these areas 

would be enhanced. Given the smaller cost per acre of effective treatment than Alternative 2, individuals and 

groups interested in reducing costs to protect resource values, would likely perceive this alternative as a more 

efficient means of controlling invasive plants.

Alternative 4 (Proposed Action) would be perceived as providing additional resource benefits with the additional 

300,000-acre reduction in weed-infested acres in 15 years and a decrease in the rate of noxious weed spread from 

7 to 6 percent. Individuals and groups who associate an improvement in commodity uses with herbicide use 

would likely perceive little change from herbicide treatment of rights-of-way because the work is taking place 

now, without herbicides. The increase in treatments for wildlife objectives would also be perceived as beneficial 

by those interested in commodity, non-commodity, and non-market values.

Alternative 5 would be perceived as contributing additional benefits associated with the annual treatment of 

approximately 4,800 additional acres, almost all of which would be habitat improvements east of the Cascades. 

Individuals and groups identified above would associate some additional benefits to their non-commodity and 

non-market values associated with these habitat improvements.

Cumulative Effects

In addition to localized effects discussed above cumulative effects to social and economic values have accrued 

and are discussed here. Historically, trade and migration routes from Europe to the New World were the major 

pathways of invasive species to the Unites States. Changing world markets have made Oregon a more important 

U.S. port increasing Oregon’s susceptibility to invasive species (Statesman Journal 2007). In addition, the

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Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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economy can be affected by a variety of factors including population growth, changes in interest rates, location 

of new industries, recession, growth of new sectors, tax policy, State economic policy, etc. which are influenced 

by regional and world market factors. When compared to these kinds of variables, the projected effect of noxious 

weeds and other invasive plants on BLM resources in Oregon has a relatively small if any effect on regional 

economic conditions. However when combined with the spread of noxious weeds and other invasive plants that 

would occur off BLM lands, effects on the regional economic conditions could occur. The rate of weed spread 

estimated to occur under Alternative 2 (and under the Reference Analysis) would have cumulative adverse effects 

on weed suppression costs on and off BLM lands within the State. While the ability to treat existing noxious weeds 

and other invasive plants will improve as more herbicides are made available, market forces of an ever-changing 

world economy make cooperative efforts across agencies, community, and cultural boundaries critically important.

Although private landowners and Federal, State, and local governments administering lands adjacent to the BLM 

will continue invasive plant treatment activities, implementation of Alternative 2 would continue to contribute 

to increased occurrence of weeds throughout Oregon relative to the action alternatives. The resulting decrease 

in biological diversity and reduction in economic and social returns would continue to adversely affect all 

stakeholders. For example, the threat to the agricultural based economy of the region posed by invasive plants 

would be aggravated by spread from BLM lands, thereby adversely affecting the continuation of agricultural 

associated lifestyles and customs. Costs incurred by adjacent land ownerships would likely continue to increase 

because of increased spread from BLM lands.

Environmental Justice

Affected Environment

Environmental justice refers to the fair treatment and meaningful involvement of people of all races, cultures, 

and incomes with respect to the development, implementation, and enforcement of environmental laws, 

regulations, programs, and policies. Executive Order 12898 requires Federal agencies to “identify and address the 

disproportionately high and adverse human health or environmental effects of its programs, policies, and activities 

on minority populations and low-income populations.” Thus, the concentrations of low income and minority 

groups, as well as trends in ethnic and racial composition of Oregon, are relevant to this analysis.

Population and Demographic Change

For the State of Oregon, the percentage of the total population identified as white, African American, and 

American Indian or Alaska Natives declined between 1990 and 2000. The percentage of Asian, Native Hawaiian, 

those persons identifying with some other race alone77, and Hispanics increased over this period (Table 4-28). 

Within individual counties:

• The percentage of total population identified as white decreased between 1990 and 2000 within all 

counties in Oregon.

• The largest increases in non-white racial groups were:

◦ Malheur County where those identified as African American increased as a percentage of total 

population by 1.2 percent;

77 Persons identifying with a single other racial group other than white, African American, American Indian or Alaska 

Native, Native Hawaiian and Other Pacific Islander, and Asian groups. 
329

Final Environmental Impact Statement, Chapter 4: Environmental Justice

◦ Klamath County American Indians and Alaska Natives increased by 1.7 percent;

◦ Multnomah County Asians increased by 2.8 percent, and;

◦ Morrow County those identifying with some other race increased by 11.1 percent.

• Individual county percentages higher than the percentage in their respective east and west side analysis 

areas indicate where higher concentrations of minorities may exist:

◦ On the east-side, all counties exceed the analysis area percentage for at least one minority group except 

Baker, Crook, Deschutes, Gilliam, Wallowa and Wheeler counties, and;

◦ West of the Cascades, all counties exceed the analysis area percentage for at least one minority group 

except Clackamas, Clatsop, and Tillamook counties (Table 4-29).

Race and ethnicity are broken out separately since Hispanics can be of any race. Between 1990 and 2000, the 

percentage of the total Oregon population of Hispanic origin increased by 4.1 percent (from 3.9 to 8 percent). 

Population numbers and the percentage of total population increased in all counties except Gilliam and 

Wallowa. The Hispanic populations of the east side and west side of Oregon increased by 3.9 percent and by 

4.1 percent, respectively.

According to the Council on Environmental Quality’s Environmental Justice Guidelines for NEPA (CEQ 1997) 

“minority populations should be identified where either: (a) the minority population of the affected area exceeds 

50 percent or (b) the minority population percentage of the affected area is meaningfully greater than the minority 

population percentage in the general population or other appropriate unit of geographic analysis.....a minority 

population also exists if there is more than one minority group present and the minority percentage, as calculated 

by aggregating all minority persons, meets one of the above stated thresholds.” The discussion above and Table 

4-29 shows the percentage of those identifying with some other race78 or Hispanics was greater in many Oregon 

counties than the total percentage on the east or west side. The concentration of minority populations within 

counties “meaningfully” greater than east and west side populations suggests they likely exist within smaller 

geographies. Thus, the U.S. Census data suggest minority populations within the analysis area likely meet the 

CEQ’s Environmental Justice criterion.

In addition to race, concentrations of low-income people and trends in the change of the population defined as low 

income are pertinent to the examination of Environmental Justice considerations. Between 1989 and 1999, the 

percentage of the Oregon population living below the Federally defined poverty level increased in nine counties, 

only two of which were west of the Cascades - Washington and Marion counties (Table 4-27). Sherman County 

(east of the Cascades) saw the largest percentage increase, while Washington County increased most in absolute 

terms by 12,377 (less than 1 percent change). In 1999 the percentage of the population living below poverty 

was slightly greater east of the Cascades (13.1 percent) than west of the Cascades (11.4 percent). In addition the 

percentage of the total population east of the Cascades decreased by a greater degree than west of the Cascades 

over the period from 1989 and 1999 - decreasing by 1.6 and 0.7 percent, respectively. In 1999, 26 counties had 

higher percentages of their populations living below the poverty level than the State percentage, 11 west of the 

Cascades and 15 east of the Cascades (Table 4-27) (US Census Bureau 2000b).

CEQ guidance on identifying low-income populations states “agencies may consider as a community either 

a group of individuals living in geographic proximity to one another, or a set of individuals (such as migrant 

workers or American Indians), where either type of group experiences common conditions of environmental 

exposure or effect.”

Examining both the racial and ethnic composition of poverty (Table 4-30), it is apparent that poverty levels 

amongst minority populations are greater than among white populations in all Oregon counties. In all counties 
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 330

except Clackamas and Curry counties, the percentage of at least one minority group was greater than its respective 

east and west side aggregated percentage in 1999, indicating concentrations of low income minorities exist 

throughout the State and likely meet the CEQ’s Environmental Justice Criterion for poverty discussed above. In 

Lane County, the percentage of people living below the poverty level exceeds the State and west side percentages 

for all minorities and Hispanics (Table 4-30).

Environmental Consequences

According to the description of the affected environment, minority and low income populations, as defined by 

CEQ, are likely present in Oregon. The presence of minority groups, low income, and American Indian tribes 

is relevant to the analysis because they may be disproportionately affected by the alternatives. These groups are 

often at a disproportionate risk compared to the general Oregon population, since they often participate in special 

uses on BLM lands. These uses include gathering food, cultural material, floral material, and other products either 

for personal or commercial use. Disproportionate risk to these groups could also result from participation in weed 

and other vegetation control work with herbicide and non-herbicide methods as part of a contract work crew.

Identification of minority populations and low-income populations primarily requires an analysis of trends and 

current populations of minorities and people living below the poverty level from U.S. Census data. Effects to 

resources important to minorities or persons living below the poverty level are one concern. The other is that 

work crews implementing weed control activities having a higher percentage of minorities and lower income 

groups could be subject to adverse effects of herbicide and non-herbicide treatments.

The potential for effects to non-target plants and animals that might be used by minority and other groups was 

determined from those respective resource sections elsewhere in this Chapter. To consider potential effects to 

Table 4-27. Population Living Below the Poverty Level

1989 1999 change

change in 

number of low 

income

1989 1999 change

change in 

number of low 

income

OREGON 12.4% 11.6% -0.8% 43873 OREGON 12.4% 11.6% -0.8% 43873

WEST-SIDE EAST-SIDE

Benton * 15.5% 14.6% -1.0% 660 Baker * 14.7% 14.7% 0.0% 218

Clackamas 6.9% 6.6% -0.4% 2866 Crook 11.1% 11.3% 0.2% 591

Clatsop * 14.4% 13.2% -1.2% -102 Deschutes 10.9% 9.3% -1.6% 2513

Columbia 10.2% 9.1% -1.2% 97 Gilliam 11.9% 9.1% -2.8% -31

Coos * 16.5% 15.0% -1.4% -484 Grant * 12.7% 13.7% 1.0% 86

Curry * 12.4% 12.2% -0.1% 185 Harney * 10.6% 11.8% 1.2% 137

Douglas * 14.9% 13.1% -1.7% -829 Hood River * 15.7% 14.2% -1.4% 235

Jackson * 13.2% 12.5% -0.7% 3344 Jefferson * 18.6% 14.6% -4.0% 244

Josephine * 18.3% 15.0% -3.3% -68 Klamath * 16.7% 16.8% 0.0% 1021

Lane * 14.5% 14.4% -0.1% 5585 Lake * 13.9% 16.1% 2.2% 192

Lincoln * 14.4% 13.9% -0.5% 560 Malheur * 19.3% 18.6% -0.7% 320

Linn 13.5% 11.4% -2.1% -560 Morrow * 15.1% 14.8% -0.3% 476

Marion * 13.2% 13.5% 0.3% 8466 Sherman * 9.9% 14.6% 4.7% 90

Multnomah * 13.1% 12.7% -0.5% 6826 Umatilla * 16.5% 12.7% -3.9% -895

Polk 13.6% 11.5% -2.1% 468 Union * 15.8% 13.8% -2.0% -346

Tillamook 15.0% 11.4% -3.6% -450 Wallowa * 15.8% 14.0% -1.8% -76

Washington 6.6% 7.4% 0.8% 12377 Wasco * 13.4% 12.9% -0.5% 172

Yamhill 11.7% 9.2% -2.6% 37 Wheeler * 20.9% 15.6% -5.3% -52

West-side totals 12.1% 11.4% -0.7% 38978 East-side totals 14.8% 13.1% -1.6% 4895

(* County percent of population greater than the State in 1999. Sources: US Census Bureau 2000a, b)
331

work crews, BLM districts provided estimates of the percentage of non-herbicide and herbicide treatments that 

would be accomplished by contract work crews for the control of noxious weeds and other invasive plants for the 

Reference Analysis and Alternatives 2 and 3. The rights-of-way and related treatments portion of Alternatives 4 

and 5 was assumed to be mostly accomplished by employees of the persons owning the developments on those 

rights-of-ways. Applicators are likely to be regular employees using equipment, and little to no disproportionate 

representation is expected.

Effects Common to All Alternatives

Work Crew Exposure

The racial composition of work crews implementing treatment activities are expected to be generally similar 

to that of the analysis area population, with potential for slightly higher percentages of minorities and lower 

income groups. Scoping suggested minority laborers who may know little English, may not be able to read 

product labels, may not have prior awareness of the health risk of using herbicides, may not be in a position to 

seek redress for being put in illegal or unsafe situations by their employers, and/or may not be able to access 

workmen’s compensation or other health care, may be at greater risk by working on herbicide application crews. 

Such a situation is conceivable, but should be considerably mitigated by current requirements that all contract 

crew members be State certified as, at minimum, Trainees. The test for a Trainee permit examines knowledge of 

applicable laws and safe handling procedures. There is a potential for disproportionate representation of minority 

and low income groups in work crews implementing herbicide treatments. To some degree, this suggests that all 

alternatives could pose an adverse risk to these groups. This risk increases with the amount of acres treated with 

herbicides under each alternative (Table 3-3), and the toxicity of those herbicides to humans. However, there are 

also risks associated with non-herbicide methods as well. For example, a reduction in chainsaw exposure is one 

factor favoring the use of herbicides in some rights-of-way.

Invasive Plant Effects

American Indian and other racial, ethnic, or low-income backgrounds participating in subsistence or cultural 

uses on BLM lands may be disproportionately affected by the spread of noxious weeds and other invasive 

plants. Populations of native plant species used for cultural purposes such as food, medicine, dress, basketry, or 

ceremonial activities are likely to be reduced because of invasive plant spread. These groups would be forced 

to seek these resources in other areas, or the resources would become less available. Some invasive plants like 

blackberries have collectable value, but such species are over-represented and spreading at the expense of native 

species. Although some culturally significant historic American Indian gathering areas may be relatively higher 

priority for weed control treatments, most areas would be expected to become infested at the same rate as BLM 

lands in general. Noxious weeds are projected to infest (be present on) approximately 1/2, 1/3, 1/4, and 2/9 of the 

BLM lands in Oregon and be spreading at a rate of 14, 12, 7 and 6 percent in 15 years for the Reference Analysis 

and Alternatives 2, 3 and 4/5 respectively under a current budget trends scenario (Table 4-4).

User Group Exposure

The same user groups that would be adversely affected by the displacement of native species by invasive plants 

could also be affected by herbicide residues or area closures associated with herbicide use under the various 

alternatives. Treatment areas would normally be posted on site, depending upon the label and an analysis of the 

risk, but that would not necessarily prevent all contact or ingestion. Site-specific planning on proposed treatments 

would include consultation with tribes, and potential mitigation measures to protect and preserve those resources 

for the people that use them. The BLM may opt to use manual and mechanical treatments in traditional use areas 

and herbicides outside of those areas.

Final Environmental Impact Statement, Chapter 4: Environmental Justice
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 332

Effects by Alternative

Reference Analysis – No Herbicide Use

Work Crew Exposure: An estimated 28,600 acres of manual and mechanical treatments would be performed by 

contract crews. Work crews may experience injury during manual and mechanical treatments, such as chainsaw 

injuries cutting hardwood trees on steep hillsides under power lines. Exposure to cutting and grubbing tool 

injuries would be comparable to those experienced by fire crews. There is no potential for human exposure to 

BLM-applied herbicides.

Invasive Plant Effects: Without herbicides, noxious weeds are projected to infest 8.6 million acres in 15 years, or 

about 1/2 of all BLM lands in Oregon. Other invasive plants would cover millions of additional acres. Native 

plants important for cultural uses could potentially be crowded out of some areas forcing American Indian users 

to seek these resources in other areas or discontinue traditional uses. Populations of culturally important plants 

could decrease to the point of being insufficient to support traditional use. Visitors from other racial, ethnic, or 

low-income backgrounds participating in subsistence or cultural uses may also be impacted. Areas important to 

these visitors for mushroom gathering, berry picking, greenery or floral materials collection or other activities 

could be adversely impacted by the spread of invasive plants.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Work Crew Exposure: An estimated 20,600 acres of manual and mechanical treatments would be performed by 

contract crews, exposing workers to tool and other injuries. In addition, approximately 15,300 acres of noxious 

weeds would be treated with herbicides by certified or licensed contract crews under this alternative. Of the 

four herbicides available under this alternative, 2,4-D has low to moderate risk from direct contact under all 

application methods, and dicamba presents a low risk to applicators from boom spraying at maximum rates.

Invasive Plant Effects: Under Alternative 2 (No Action), noxious weeds are projected to infest 5.9 million acres 

in 15 years, or about 1/3 of all BLM lands in Oregon. Other invasive plants would cover millions of additional 

acres. Native plants important for cultural uses could be crowded out of some areas forcing American Indian 

users to seek these resources in other areas or discontinue traditional uses. Populations of culturally important 

plants could decrease to the point of being insufficient to support traditional use. Visitors from other racial, 

ethnic, or low-income backgrounds participating in subsistence or cultural uses may also be impacted. Areas 

important to these visitors for mushroom gathering, berry picking, greenery collection or other activities could be 

adversely impacted by the spread of invasive plants.

User Group Exposure: An estimated 16,700 acres would be treated with herbicides under this alternative. 

American Indian and visitors from other racial, ethnic, or low-income backgrounds participating in subsistence or 

cultural uses could be adversely affected by herbicide exposure, or by inadvertent effects to non-target culturally 

important plants, or to wildlife species of value to these groups. However, treatment design would attempt to 

minimize exposure of non-target food and water sources. In addition, Standard Operating Procedures require 

consultation with tribes to locate any areas of vegetation that are significant to the tribes and that might be affected 

by herbicide treatments. Despite these measures, the potential for disproportionate or adverse impacts to minority 

or low-income work crews would still exist.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Work Crew Exposure: An estimated 17,100 acres of manual and mechanical treatments would be performed by 

contract crews, exposing workers to tool and other injuries. In addition, approximately 27,000 acres of noxious 

weeds would be treated with herbicides by contract crews under this alternative. Twelve or 13 herbicides 

would be available on the west and east side respectively, providing project planners with opportunities to select 
333

herbicides that are used at lower rates, and present lower risks, than those available under Alternative 2 (No 

Action). Use of 2,4-D and dicamba would be lower than under Alternative 2, but hexazinone, triclopyr, and 

chlorsulfuron present a risk (albeit low) under at least one worker exposure scenario at the maximum rate.

Invasive Plant Effects: Under Alternative 3, noxious weeds are projected to infest 4.0 million acres in 15 years, 

or about 1/4 of all BLM lands in Oregon. Other invasive plants would cover millions of additional acres. Native 

plants important for cultural uses could potentially be crowded out of some areas forcing American Indian users 

to seek these resources in other areas or discontinue traditional uses. Populations of culturally important plants 

could decrease to the point of being insufficient to support traditional use. Visitors from other racial, ethnic, or 

low-income backgrounds participating in subsistence or cultural uses may also be impacted. Areas important to 

these visitors for mushroom gathering, berry picking, greenery collection or other activities could be adversely 

impacted by the spread of invasive plants.

User Group Exposure: An estimated 30,300 acres would be treated with herbicide under this alternative, an 

increase of 13,600 acres when compared to the No Action Alternative (Alternative 2). American Indian and 

visitors from other racial, ethnic, or low-income backgrounds participating in subsistence or cultural uses could 

be adversely affected by herbicide exposure, or by inadvertent effects to non-target culturally important plants, or 

to wildlife species of value to these groups. However, treatment design would attempt to minimize exposure of 

non-target food and water sources. In addition, Standard Operating Procedures require consultation with tribes to 

locate any areas of vegetation that are significant to the tribes and that might be affected by herbicide treatments. 

Despite these measures, the potential for disproportionate or adverse impacts to minority or low-income work 

crews would still exist. 

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

Work Crew Exposure: Work crews may experience injury during manual and mechanical treatments, with risks 

expected to be similar to those described for Alternative 3. Contract treatments are projected to increase less than 

5,000 acres from Alternative 3.

Invasive Plant Effects: Under Alternative 4, noxious weeds are projected to infest 3.7 million acres in 15 years, 

or about 2/9 of all BLM lands in Oregon. Other invasive plants would cover millions of additional acres. Native 

plants important for cultural uses could potentially be crowded out of some areas forcing American Indian users 

to seek these resources in other areas or discontinue traditional uses. Populations of culturally important plants 

could decrease to the point of being insufficient to support traditional use. Visitors from other racial, ethnic, or 

low-income backgrounds participating in subsistence or cultural uses may also be impacted. Areas important to 

these visitors for mushroom gathering, berry picking, greenery collection or other activities could be adversely 

impacted by the spread of invasive plants.

User Group Exposure: An estimated 45,200 acres would be treated with herbicides under this alternative, an 

increase of 14,800 acres from Alternative 3. Approximately 2/3 of the increase would be spraying native and 

other non-invasive plants along roads, rights-of-ways, and other developments. To the degree some user groups 

collect products within a few feet of the road edge, as might occur with blackberries for example, exposure would 

be increased. Under Alternative 4, these plants would be deliberately targeted, increasing the potential to affect 

plants and other products (which include other forest products such as mushrooms, manzanita, and greenery for 

wreaths) utilized by under-represented groups.

As with Alternatives 2 and 3, however, treatment design would attempt to minimize exposure of non-target 

food and water sources. In addition, Standard Operating Procedures require consultation with tribes to locate 

any areas of vegetation that are significant to the tribes and that might be affected by herbicide treatments. 

Despite these measures, the potential for disproportionate or adverse impacts to minority or low-income work 

crews would still exist. 

Final Environmental Impact Statement, Chapter 4: Environmental Justice
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 334

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

Work Crew Exposure: Work crews may experience injury during manual and mechanical treatments, with risks 

expected to be similar to those described for Alternative 3. Contract herbicide treatments could increase as much 

as 8 to 9,000 acres compared to Alternative 3, but the type of exposure would be similar.

Invasive Plant Effects: Effects from invasive plants would be essentially the same as described for Alternative 4 

(Proposed Action).

User Group Exposure: Alternative 5 would increase herbicide treatments on an additional 4,800 acres when 

compared to Alternative 4 (Proposed Action), with the increase primarily applying to treatment of native plants for 

habitat improvement and other vegetation treatments not designed for livestock forage or timber production. The 

risk to plants and other resources used by American Indian and other under-represented groups on a per-acre basis 

would be higher than under Alternatives 2 and 3, because treatments would target native and other non-invasive 

plants, which could affect forest products such as mushrooms, manzanita, and greenery for wreaths. Inadvertent 

treatment of areas not identified as important to other racial, ethnic, or low-income backgrounds participating in 

subsistence or cultural uses would be highest under this alternative.

However, treatment design would attempt to minimize exposure of non-target food and water sources. Habitat or 

fuels treatments under this alternative would normally target areas where total vegetation, or a specific species, 

has become over-abundant. In addition, Standard Operating Procedures require consultation with tribes to 

locate any areas of vegetation that are significant to the tribes and that might be affected by herbicide treatments. 

Despite these measures, the potential for disproportionate or adverse impacts to minority or low-income work 

crews would still exist.

Cumulative Effects

With growing populations of minority (Table 4-28) and low-income populations (Table 4-27) throughout the 

State, the cumulative effects on Environmental Justice are relevant. As Hispanic, American Indian, and other 

minority or low-income populations continue to grow, the likelihood of these groups using public lands is likely 

to increase. Combined with increasing levels of treatment, the possibility increases that effects associated 

with vegetation treatments would disproportionately affect these minority populations. These combined trends 

illustrate the importance of site-specific consideration of the potential to affect under-represented groups, and 

American Indian consultation, conducted during planning for future herbicide treatment projects.
335

Table 4-28. Racial and Ethnic Change Compared to the Total Population Change in Oregon, by County

(1990 to 2000)

White 

alone

Black or 

African 

American 

alone

American 

Indian and 

Alaska Native 

alone

Asian 

alone

Native Hawaiian 

and Other Pacific 

Islander alone

Some 

other 

race 

alone

Hispanic*

OREGON -6.4% 0.0% -0.2% 0.7% 0.0% 2.5% 4.1%

WEST-SIDE COUNTIES

Benton -2.9% 0.1% -0.2% -1.2% 0.0% 1.0% 2.5%

Clackamas -5.3% 0.3% -0.1% 0.8% 0.1% 1.5% 2.5%

Clatsop -3.9% 0.4% -0.2% 0.0% 0.0% 0.9% 2.4%

Columbia -2.5% 0.2% -0.2% -0.4% 0.0% 0.2% 0.3%

Coos -4.1% 0.0% -0.2% -0.3% 0.0% 0.7% 0.8%

Curry -3.1% 0.1% -0.7% 0.5% -0.1% 0.6% 1.7%

Douglas -2.9% 0.0% -0.2% 0.0% -0.2% 0.3% 0.6%

Jackson -4.0% 0.2% -0.6% -0.1% 0.1% 1.3% 2.6%

Josephine -3.2% 0.0% -0.3% 0.1% 0.0% 0.5% 1.4%

Lane -4.9% 0.0% 0.0% 0.1% 0.0% 1.2% 2.0%

Lincoln -5.6% 0.1% 0.2% 0.1% 0.0% 1.5% 3.0%

Linn -4.0% 0.0% 0.1% 0.1% 0.1% 1.0% 1.8%

Marion -9.8% 0.0% -0.2% 0.1% 0.1% 6.4% 9.6%

Multnomah -8.2% -0.6% -0.2% 1.3% 0.1% 3.1% 4.5%

Polk -3.9% -0.1% 0.0% 0.1% 0.1% 1.0% 3.3%

Tillamook -3.0% -0.2% -0.8% 0.1% 0.0% 1.3% 3.5%

Washington -10.0% 0.4% 0.0% 2.8% 0.1% 3.4% 6.5%

Yamhill -5.2% 0.0% -0.3% 0.1% -0.1% 2.8% 4.0%

West-side Totals -6.5% -0.1% -0.2% 0.8% 0.1% 2.5% 4.1%

EASTSIDE COUNTIES

Baker -2.4% 0.1% -0.1% 0.2% 0.1% 0.5% 0.1%

Crook -4.3% 0.0% -0.4% 0.2% 0.0% 3.2% 3.1%

Deschutes -2.8% 0.1% -0.4% 0.0% -0.1% 1.1% 1.8%

Gilliam -2.0% 0.1% 0.5% -0.4% 0.0% 1.0% -1.0%

Grant -1.6% 0.0% -0.2% -0.1% 0.0% 0.0% 0.4%

Harney -4.3% 0.1% 0.1% 0.2% 0.1% -0.2% 1.4%

Hood River -11.9% 0.0% -1.0% -0.1% -0.1% 10.5% 9.4%

Jefferson -5.7% -0.1% -4.2% 0.2% 0.0% 6.4% 7.2%

Klamath -5.3% -0.2% 0.1% 0.3% 0.1% 1.4% 2.6%

Lake -4.6% -0.2% 1.7% 0.2% -0.5% 0.7% 1.2%

Malheur -5.7% 1.2% -0.1% -1.3% 0.0% 3.0% 5.4%

Morrow -14.3% 0.1% 0.5% 0.2% -0.1% 11.1% 13.4%

Sherman -5.9% 0.6% 1.3% 0.5% 0.0% 0.8% 3.2%

Umatilla -7.0% 0.4% -0.1% 0.0% 0.0% 4.6% 7.4%

Union -2.4% 0.1% -0.5% 0.1% 0.1% 1.0% 0.8%

Wallowa -1.2% 0.0% -0.1% -0.3% 0.0% 0.1% -0.8%

Wasco -6.2% 0.0% -0.2% 0.3% -0.3% 3.6% 4.2%

Wheeler -4.2% 0.1% 0.1% -0.1% 0.0% 1.7% 2.2%

Eastside Totals -5.1% 0.1% -0.4% 0.0% 0.0% 2.9% 3.9%

(*Hispanics or Latinos may be of any race. Sources: US Census Bureau 2000a)

Final Environmental Impact Statement, Chapter 4: Environmental Justice
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 336

Table 4-29. Racial and Ethnic Share of 2000 Population

White 

alone

Black or 

African 

American 

alone

American 

Indian and 

Alaska Native 

alone

Asian 

alone

Native Hawaiian 

and Other Pacific 

Islander alone

Some 

other 

race 

alone

Hispanic*

OREGON 86.4% 1.6% 1.3% 2.9% 0.2% 4.3% 8.0%

WEST-SIDE COUNTIES

Benton 89.0% 1.0% 0.7% 4.3% 0.1% 1.8% 4.6%

Clackamas 91.2% 0.6% 0.6% 2.4% 0.2% 2.3% 5.0%

Clatsop 92.5% 0.7% 0.9% 1.0% 0.2% 1.8% 4.6%

Columbia 94.2% 0.3% 1.3% 0.5% 0.1% 0.9% 2.3%

Coos 91.5% 0.2% 2.6% 0.5% 0.1% 1.2% 3.2%

Curry 93.0% 0.1% 2.4% 0.8% 0.0% 1.0% 3.3%

Douglas 93.7% 0.2% 1.6% 0.6% 0.0% 0.9% 2.8%

Jackson 91.6% 0.4% 1.1% 0.8% 0.2% 2.9% 6.7%

Josephine 93.7% 0.2% 1.3% 0.5% 0.0% 1.3% 4.2%

Lane 90.5% 0.8% 1.1% 1.9% 0.2% 2.0% 4.5%

Lincoln 90.3% 0.2% 2.7% 0.7% 0.3% 1.9% 4.7%

Linn 93.0% 0.2% 1.4% 0.8% 0.2% 1.8% 4.1%

Marion 81.7% 0.9% 1.3% 1.7% 0.3% 10.6% 17.2%

Multnomah 79.0% 5.4% 1.0% 5.6% 0.4% 4.1% 7.5%

Polk 89.3% 0.3% 1.6% 1.2% 0.2% 4.5% 8.8%

Tillamook 94.4% 0.2% 0.5% 0.5% 0.1% 1.7% 5.1%

Washington 82.0% 1.0% 0.7% 6.7% 0.3% 5.9% 11.1%

Yamhill 89.2% 0.7% 1.2% 1.0% 0.1% 5.1% 10.6%

West-side Totals 86.3% 1.7% 1.1% 3.2% 0.2% 4.0% 7.7%

EASTSIDE COUNTIES

Baker 96.0% 0.3% 0.7% 0.5% 0.1% 0.7% 1.9%

Crook 92.5% 0.0% 1.7% 0.3% 0.0% 4.0% 5.6%

Deschutes 94.8% 0.2% 0.9% 0.5% 0.1% 1.5% 3.8%

Gilliam 96.8% 0.1% 1.0% 0.3% 0.0% 1.0% 1.4%

Grant 95.8% 0.0% 1.3% 0.1% 0.0% 0.9% 2.7%

Harney 90.3% 0.1% 3.6% 0.8% 0.2% 1.0% 4.5%

Hood River 78.7% 0.2% 0.9% 1.4% 0.1% 16.2% 25.1%

Jefferson 68.7% 0.1% 15.3% 0.6% 0.1% 11.9% 17.6%

Klamath 87.2% 0.5% 4.1% 0.7% 0.2% 3.6% 7.8%

Lake 90.5% 0.0% 3.2% 0.7% 0.1% 2.8% 4.9%

Malheur 75.7% 1.4% 0.9% 1.6% 0.1% 17.4% 25.7%

Morrow 75.0% 0.2% 1.7% 0.5% 0.0% 20.2% 24.4%

Sherman 92.5% 0.6% 2.1% 0.7% 0.0% 1.3% 4.7%

Umatilla 82.0% 1.0% 3.2% 0.7% 0.1% 10.9% 16.1%

Union 94.5% 0.5% 0.6% 0.9% 0.6% 1.5% 2.3%

Wallowa 97.8% 0.0% 0.4% 0.0% 0.1% 0.2% 0.7%

Wasco 86.4% 0.4% 3.5% 0.9% 0.1% 5.9% 9.3%

Wheeler 95.2% 0.1% 0.5% 0.0% 0.0% 1.7% 3.4%

East-side Totals 87.1% 0.5% 2.7% 0.7% 0.1% 6.5% 10.5%

(*Hispanics or Latinos may be of any race. Sources: US Census Bureau 2000a)
337

Table 4-30. Population Living Below the Poverty Level in Oregon, by County, Race, and Ethnicity

White

Black or 

African 

American

American 

Indian & 

Alaska Native

Asian

Native Hawaiian 

& Other pacific 

Islander

Some 

Other 

Race

Hispanic 

or Latino*

OREGON 10% 24% 22% 12% 18% 27% 25%

WESTSIDE COUNTIES

Benton 13% 24% 15% 38% 11% 21% 25%

Clackamas 6% 10% 9% 5% 16% 26% 21%

Clatsop 12% 52% 19% 15% 22% 48% 45%

Columbia 8% 15% 17% 11% 15% 35% 26%

Coos 14% 29% 25% 17% 39% 14% 22%

Curry 12% 0% 15% 1% 0% 3% 7%

Douglas 13% 12% 18% 11% 17% 32% 28%

Jackson 12% 24% 20% 18% 10% 29% 26%

Josephine 14% 13% 25% 14% 13% 27% 24%

Lane 13% 26% 24% 31% 26% 28% 27%

Lincoln 13% 16% 30% 12% 21% 35% 29%

Linn 11% 19% 20% 9% 3% 30% 26%

Marion 11% 31% 19% 13% 30% 27% 27%

Multnomah 10% 26% 22% 13% 14% 30% 26%

Polk 10% 31% 22% 14% 4% 27% 29%

Tillamook 11% 77% 13% 16% 0% 32% 39%

Washington 6% 11% 11% 8% 21% 24% 21%

Yamhill 8% 6% 6% 18% 3% 21% 20%

West-Side Totals 10% 24% 19% 13% 18% 27% 25%

EASTSIDE COUNTIES

Baker 14% 7% 40% 17% 100% 33% 29%

Crook 10% 0% 32% 0% NA 34% 37%

Deschutes 9% 42% 26% 10% 0% 24% 20%

Gilliam 9% 0% 0% 0% NA 47% 35%

Grant 13% NA 27% 0% 0% 44% 24%

Harney 10% 0% 36% 10% 42% 24% 22%

Hood River 12% 0% 14% 9% 0% 28% 34%

Jefferson 10% 0% 32% 0% 0% 19% 22%

Klamath 15% 17% 40% 11% 3% 37% 32%

Lake 15% NA 28% 0% 25% 32% 30%

Malheur 16% 47% 39% 4% 72% 30% 28%

Morrow 11% 41% 15% 20% 0% 27% 27%

Sherman 14% 0% 20% 21% NA 73% 39%

Umatilla 10% 33% 21% 6% 29% 25% 23%

Union 13% 24% 21% 16% 35% 18% 24%

Wallowa 14% NA 15% 0% 100% 0% 33%

Wasco 11% 9% 24% 11% 33% 21% 25%

Wheeler 14% 0% 0% NA NA 56% 60%

East-side Totals 11% 27% 30% 9% 22% 27% 27%

(*Hispanics or Latinos may be of any race. NA indicates counties contained no population of that minority.

Sources: US Census Bureau 2000a)

Final Environmental Impact Statement, Chapter 4: Environmental Justice
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 338

Implementation Costs

This section examines the direct costs of implementing the various alternatives. Examined for each alternative are 

total direct costs, direct costs per effectively treated acre, and cost savings (where applicable) from substituting 

one treatment method for another for activities that must be conducted regardless of the alternative selected. 

BLM funding is finite; funds spent in one place usually means less funding is available to be spent elsewhere. No 

attempt is made to estimate the cost/benefit of these potential alternative uses for funds.

Costs are arguably not a potential effect on the human environment and thus the section is not necessarily 

required by NEPA. However, in this case, it furthers NEPA objectives to display the factors that will be used by 

the decision-maker to select from among the alternatives, and cost-effectiveness is thus identified as a Purpose

in Chapter 1. BLM planning policy specifies that management actions having a high likelihood of improving 

resource conditions for relatively small expenditures of time and money should receive relatively higher priority 

(USDI 2005f:34). This section helps furthers these decision-making objectives.

This section does not assign a dollar value to resources impacted by invasive weeds. It is difficult to assess the 

monetary value for many of the resource values obtained from public lands. The various degrees of infestation 

would add complexity to those estimates. However, the various resource sections in this Chapter describe the 

negative effects in qualitative terms. Invasive weeds increase management costs, decrease resource values and 

outputs, and exacerbate the effects of natural and human-caused resource disturbances. See Cumulative Effects at 

the end of this section for further information.

Treated Acres and Effectively Treated Acres, by Alternative

Treated Acres

An estimate of the acres of noxious weeds and other invasive plants that would be treated annually with each 

herbicide and each non-herbicide treatment method, for each alternative, is presented in Table 3-3. Included also 

are estimated acres of rights-of-way/recreation site/administrative site herbicide treatments, and habitat and other 

vegetation treatments that would occur with herbicides if herbicides were available for those purposes (Alternatives 4 

and/or 5). Table 3-3 acres are a compilation of estimates made by the nine BLM districts in Oregon using a “current 

budget trends” assumption, and represent an estimated average annual treatment level for the next 10 to 15 years. 

Table 3-3 acres applicable to this cost analysis are summarized in Table 4-31 below, for reference.

Actual annual treatment levels could vary based on changes in program emphasis or priorities, fluctuations in 

annual budgets, opportunities for cost savings with partnerships, and the availability of external funding. Since 

project related actions may be implemented through cooperative agreements, multiple partners may bear these 

costs. State and local governments, adjacent land owners, Cooperative Weed Management Areas, interest groups, 

and right-of-way and other permit holders will contribute to or fully fund some vegetation treatments, especially 

where those parties own, or have interests in, a potentially affected area or development. Although a rough 

estimate of the percentage of each vegetation treatment category to be accomplished by Federal versus nonFederal work forces is possible (to identify BLM’s portion of the work), especially for rights-of-way and related 

work in Alternatives 4 and 5, such a breakdown is not necessarily relevant to comparing the alternatives, since 

most costs are ultimately borne by (and benefits accrue to) a general cross section of the public78. Therefore, 

78 Most rights-of-way treatments, for example, would be done by the State, counties, or utility companies and costs are 

borne by taxpayers or ratepayers.
339

Final Environmental Impact Statement, Chapter 4: Implementation Costs

the estimated costs and benefits of all herbicide uses on BLM lands that would occur under each alternative are 

reported together and not allocated between partners (Table 4-31).

Effectively Treated Acres

The Noxious Weeds and other Invasive Plants section in this Chapter explains that invasive weed control 

treatments are not 100 percent effective at controlling invasive weed populations on the first try. Under each 

alternative, some level of retreatment would be necessary to achieve complete control. A five-acre treatment, for 

example, would be monitored to detect additional or remaining plants, and some portion of those acres would 

likely require retreatment. The amount of retreatment necessary is a function of how effective the prior treatment 

is. For the Reference Analysis, for example, nearly two-thirds of the noxious weeds in Oregon cannot be 

effectively controlled with non-herbicide methods. Further, non-herbicide methods (particularly mechanical and 

directed livestock treatments) often disturb soils leading to reinvasion, and plants are more likely to be moved off 

site. Mechanical treatments of re-sprouting woody species may temporarily reduce the vigor of these species, but 

not kill the weed.79

“Effective” treatments for each alternative are the portion of the treatments that successfully control the invasive 

weeds on the treated site and thus prevent future weed spread. The percentage of treatments meeting this 

definition varies by alternative and is estimated to be 30, 60, and 80 percent of the total weed treatments for the 

Reference Analysis and Alternatives 2 and 3-5 respectively (Table 4-31). It is most appropriate to look at cost 

per effectively treated acres, because the overarching objective is to control weeds and prevent their spread. The 

efficacy of herbicide treatments for objectives other than control of invasive plants under Alternatives 4 and 5 is 

assumed to be effective, since complete plant removal is usually not the objective.

Costs by Treatment Method

Direct project-level costs were provided by each of the nine BLM districts for herbicide treatments and for 

non-herbicide methods. Costs include equipment, materials, wages, and contract costs; they do not include 

program planning (e.g., NEPA) or overhead. Costs on the east and west sides of the Cascades are averaged 

separately because there are substantial differences between the two areas in terms of factors that affect costs, 

like topography, size and density of vegetation, and moisture regime. The acreage-weighted averages of these 

estimates are shown in Table 4-32. Costs are not discounted since all costs are annual averages in 2008 dollars, 

79 Not being able to kill the weed does not mean the treatments are a waste of time. Treatments may prevent seed 

production or other spread, and thus meet objectives of containing infestations and preventing spread.

Table 4-31. Estimated Annual Acres of Noxious/Invasive Weed Treatment by Alternative

Method Reference Analysis Alt. 2 (No Action) Alts. 3-51

Invasive with non-herbicide methods 42,100 28,800 28,100

Invasive with herbicide methods - 16,700 30,300

Total Treated 42,100 45,500 58,400

Percent Effective2 30 % 60 % 80 %

Total Treated Effectively 12,630 27,300 46,1603

1

 The noxious weed/invasive plant portions of Alternatives 3 through 5 are the same.

2

 From the Noxious Weeds and other Invasive Plants section in this chapter. 3

 Does not include 2,350 acres of noxious weeds incidentally killed by right-of-way treatments of native and other non-invasive plants in 

Alternatives 4 and 5 and not included in invasive weed cost per acre calculations.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 340

and apply equally to all years. Providing a discounted total of all costs over the next 10 or 15 years would not 

change the relative difference between the alternatives.

Herbicide application costs were averaged even though the cost of the herbicides themselves varies. The 

potential difference the additional calculations would have made was not judged to be significant to a reasonable 

comparison of the alternatives.

Table 4-32. Average Direct Cost of Treatment by Treatment Method, per Acre, East and West of the Cascades

Method Cost per acre

W1 E

Non-herbicide

Mechanical $225 $222

Manual $345 $90

Prescribed Fire for Weed Control $340 $48

Directed Livestock $284 $250

Seeding of Planting $199 $108

Herbicides: Noxious & Invasive Weeds

Herbicide Application $107 $118

Herbicides: Rights-of-Way & Wildlife/Other

Herbicide Application $107 $118 1

 West/East of the Cascades

Table 4-33. Annual Cost of Noxious Weed/Invasive Plant Treatment per Alternative

Method Reference Analysis Alt. 2 (No Action) Alts. 3-51

W E W E W E

Non-Herbicide $2,371,941 $4,769,567 $1,921,718 $2,741,639 $1,806,178 $3,627,714

Herbicide $0 $0 $746,200 $1,141,903 $852,800 $2,625,201

Total cost $7,141,508 $6,551,460 $8,911,892

Cost per acre 

effectively treated $565 $240 $193

1

 The noxious weed/invasive plant portions of Alternatives 3 through 5 are the same.

Total Cost and Cost per Effectively Treated Acre by Alternative 

The noxious weed and other invasive plant control treatment acres are predicted to increase under alternatives 

making more herbicides available, e.g., Alternative 3 would treat more acres than Alternative 2 (No Action), 

and Alternative 2 would treat more acres than the Reference Analysis. Reasons for this increase include: 1) the 

additional herbicides provide tools to control weeds not presently treated or at least not treated effectively; 2) the 

additional herbicides make control treatments more efficient and therefore more treatments can be done within 

existing funding; 3) additional cooperator and permit-holder funding sources become available as it becomes 

practical to treat more species; and 4) approving herbicides currently used on adjacent non-BLM lands would 

encourage cooperative weed management across ownerships.

Total costs generally increase as successive alternatives treat more acres. However, the cost per effectively treated 

acre decreases as the effectiveness of the alternatives increases (Table 4-33). This decrease is wholly related to 

the increased efficiency of having more control tools available.
341

Effects by Alternative

Reference Analysis – No Herbicide Use

The annual cost of implementing treatments is greater than Alternative 2 (No Action) (in spite of fewer acres 

treated), but less than all other alternatives at a total of $7,141,508 in 2008 dollars (Table 4-34). Despite the 

relatively lower cost of treatment, the cost per acre treated effectively is the higher than any of the alternatives at 

$565 per acre (Table 4-33).

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

The annual cost of implementing treatments is $6,551,460 in 2008 dollars, the least of all alternatives. Costs of 

herbicide treatment for invasive plants are less than the cost of herbicide treatments under the action alternatives 

for both the east and west-sides. However, reduced effectiveness of treatment makes the treatment cost per acre 

higher than the action alternatives, at $240 per acre (Table 4-33).

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

The annual cost of implementing treatments is more than the Reference Analysis or the No Action Alternative 

(Alternative 2), at $8,911,892 in 2008 dollars. However, increased effectiveness of treatment makes the treatment 

cost per acre lower than all other alternatives at $193 (Table 4-33).

Although indirect benefits of each alternative are qualitatively discussed at the end of this section, it should be 

noted that an effect specific to this alternative would be the ability to control invasive annual grasses, potentially 

reducing the risk of wildfire adjacent to communities (the wildland urban interface) east of the Cascades.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses and Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation 

Management Objectives

The effects and costs for Alternative 3 apply equally to the noxious weeds and other invasive plant treatment 

portion of Alternatives 4 and 5 as well. However, Alternative 4 would also make herbicides available for treating 

native and other non-invasive vegetation encroaching on the safety and function of rights-of-way, administrative 

sites, and recreation sites (9,300 acres), and for certain habitat treatments (5,700 acres). Alternative 5 would 

include all of the treatments in Alternative 4, and would add about 4,800 more acres of herbicide treatments 

for habitat improvement and other vegetation management not including those for livestock forage or timber 

production. Only these additional uses are discussed here.

Rights-of-Way, Administrative Sites, and Recreation Sites: For controlling native and other non-invasive 

vegetation affecting the safety and function of rights-of-way, administrative sites, and recreation sites, agencies 

and partners are currently accomplishing needed vegetation control work with non-herbicide methods. The 

9,300 acres proposed for herbicide use for these objectives under Alternatives 4 and 5 (Table 3-3) thus represent 

a corresponding number of acres of non-herbicide treatments already taking place.80 (The remainder of annual 

vegetation treatment needs along rights-of-way and other developments would continue to be accomplished with 

non-herbicide methods.) For cost comparison purposes, 10 percent of the herbicide treatments are assumed to 

80 These current rights-of-way and other sites non-herbicide native vegetation treatments are not displayed on Tables 3-3 

or 4-31 to avoid confusion with the non-herbicide noxious weed/invasive plant control treatments

Final Environmental Impact Statement, Chapter 4: Implementation Costs
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 342

replace existing manual treatments, while 90 percent are assumed to replace existing mechanical methods. Using 

herbicides to meet the annual vegetation control needs on 9,300 acres of rights-of-way, roads, and around other 

developments would save nearly $1 million per year (Table 4-34).

Table 4-34. Annual Cost for Rights-of-Way/Administrative Sites/Recreation Sites Treatments.

Alts 1-3

(Non-herbicide)

Alts 4 and 5

(Herbicide)

Treatments for Rights-of-Way/Administrative Sites/Recreation site objectives

Cost East of the Cascades $1,566,188 $882,915 

Cost West of the Cascades $449,752 $202,540 

Total cost $2,015,940 $1,085,455

Acres 9,300 9,300

Average Cost per Acre $217 $117

Habitat and Other Objectives: Of the acres proposed for herbicide use to accomplish habitat improvement 

objectives under Alternative 4 (5,700 acres), and wildlife and other objectives under Alternative 5 (an additional 

4,800 acres), about 35 percent are already being done with non-herbicide methods and 65 percent represents new 

opportunities because of the availability of herbicides. The 35 percent already being done with non-herbicide 

methods costs about $217 per acre. Doing these same treatments with herbicides would cost an average of $117 

per acre. The availability of herbicides would lead to the accomplishment of nearly three times more acres in 

part because of the reduced cost, but in part because many needed treatments cannot be accomplished with nonherbicide methods because they would be too labor intensive, difficulties in targeting the correct plant species or 

age group, or would cause site disturbances that would negate all or part of the treatment objective.

Alternative 4 would make herbicides available to treat any vegetation to achieve habitat goals specified in 

approved Recovery Plans or other plans specifically identified as part of recovery or delisting plans, Conservation 

Strategies, or Conservation Agreements for Federally Listed and other Special Status species. The 5,700 acres of 

treatments proposed in Alternative 4 to meet this objective would cost $668,800 if accomplished with herbicides. 

No corresponding non-herbicide cost is calculated because the same acres would not be attempted with nonherbicide methods.

In addition to the habitat treatments described for Alternative 4, Alternative 5 would make herbicides available for 

the full range of objectives and uses approved nationally in the Record of Decision for the PEIS except projects 

specifically to improve livestock forage or timber production. Districts indicated most additional treatments under 

this alternative would be thinning western juniper and sagebrush for habitat improvement, or possibly treating fuels 

east of the Cascades, although other uses are possible. The additional 4,800 acres projected to be treated to meet 

these objectives under Alternative 5 would cost $574,700 if accomplished with herbicides. No corresponding nonherbicide cost is calculated because the same acres would not be attempted with non-herbicide methods

Non-Quantified and Cumulative Effects

Management of invasive plants affects the goods, services, and uses provided by BLM land and the costs of 

managing those lands. Increased operating costs due to invasive plant management may result in direct or indirect 

transfer of costs to land management programs or users of BLM lands. Noxious weed and other invasive plant 

management may compete with other important land management needs, resulting in cost tradeoffs; management 

of timber, vegetation, roads, public access, grazing, recreation, habitat, minerals, and fire may be affected by cost 
343

Final Environmental Impact Statement, Chapter 4: Human Health and Safety

increases or loss of opportunity due to invasive plant management. Invasive plant and other treatments would 

result in improvements in the condition of BLM resources and would lead to increases in commodity and noncommodity values. Treatments would also increase the quantity and quality of wildlife forage, reduce fire hazard, 

and reduce other negative effects from noxious weed and other and invasive plant spread. Improved recreation 

opportunities, reductions in risk of wildfires, improvements of rights-of-way, and habitat improvements would 

benefit the economies of rural communities, which are often dependent on recreational opportunities and other 

natural resource-based businesses.

Human Health and Safety

Affected Environment

Background Health Risks

People living in Oregon are exposed to a variety of risks common to the U.S. as a whole, including automobile 

accidents and other injuries; contaminants in the air, water, soil, and food; smoking, alcohol and various diseases. 

Risks to workers may differ from those facing the public, depending on the nature of a person’s work. Some of 

these risks may be quantified, but a lack of data allows for only a qualitative description of certain risks. Human 

Health information was obtained from the Centers for Disease Control and Prevention (CDC), the National 

Center for Injury Prevention and Control (NCIPC), the National Center for Health Statistics (NCHS), the National 

Institute for Occupational Safety and Health (NIOSH), and the Bureau of Labor Statistics.

Risks from Diseases

Disease Incidence

Despite the difficulties in establishing correlations between work conditions and disease, only certain illnesses 

have been linked to occupational hazards. For example, asbestosis and lung cancer among insulation and 

shipyard workers has been linked to their exposure to asbestos (NTP 2009). Pneumoconiosis among coal miners 

has been correlated with the inhalation of coal dust. Occupational exposures to some metals, dusts, and trace 

elements, carbon monoxide, carbon disulfide, halogenated hydrocarbons, nitroglycerin, and nitrates can result 

in increased incidence of cardiovascular disease. Neurotoxic disorders can arise from exposure to a wide range 

of chemicals, including some pesticides.81 Dermatological conditions like contact dermatitis, infection, trauma, 

cancer, vitiligo, urticaria, and chloracne have a high occurrence in the agricultural, forestry, and fishing industries.

Injury and Disease Mortality

Mortality rates for Oregon compared with national statistics are listed in Table 4-35. The five most common 

causes of death in the U.S., as well as in Oregon, are heart disease, cancer, cerebrovascular disease (stroke), 

respiratory disease, and accidents. Oregon has lower than average mortality rates for cancer, heart disease, and 

injuries and higher incidence for stroke and respiratory disease.

81 Pesticides include insecticides, rodenticides, fungicides, herbicides, and other “pest” control materials.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 344

Risks from Cancer

Cancer Incidence

Nationwide, the chance of developing some form of cancer during one’s lifetime is estimated to be about one 

in three (NCI 2005). There are many causes of cancer development, including genetic, viral, and occupational 

exposure to carcinogens, environmental contaminants, and substances in food. In the U.S., one-third of all 

cancers are attributed to tobacco smoking. Work-related cancers are estimated to account for 4 percent to 20 

percent of all malignancies. It is difficult to quantify the information because of the long time intervals between 

exposure and diagnosis, personal behavior patterns, job changes, and exposure to other carcinogens. The NIOSH 

has reported that approximately 20,000 cancer deaths and 40,000 new cases of cancer each year in the U.S. are 

attributable to occupational hazards. Millions of U.S. workers are exposed to substances that have tested as 

carcinogens in animal studies (NIOSH 2009b).

Cancer Mortality

Cancer accounted for 23 percent of all deaths in Oregon in 2003. Nationwide, cancer accounts for approximately 

24 percent of all fatalities (NCHS 2007). Generally, males have higher rates of cancer mortality than females, and 

African Americans have higher rates than Caucasians.

Injury Risk from Using Herbicides and Non-Herbicide Treatments

Manual and mechanical treatments can present health hazards to forestry workers. Adverse weather and terrain 

commonly create unfavorable working conditions and increased hazards. Hazards associated with adverse 

weather conditions include extreme heat and cold, which can be exacerbated by very dry and very wet conditions. 

Other hazards include falling objects (especially when cutting trees), tripping or slipping on hazards on the 

ground, protruding objects such as branches and twigs, poisonous plants and insects, and dangerous wildlife.

Tools and equipment present inherent hazards, such as sharp edges on the tools themselves, and the hazardous 

nature of fuels and lubricants used in mechanized equipment. Manual and mechanical methods present potential 

ergonomic hazards related to lifting and carrying equipment, and when pulling vegetation.

Injuries can vary from minor cuts, sprains, bruises, and abrasions to major arterial bleeding, compound bone fractures, 

serious brain concussions, and death. Workers are subject to heat-related illness or hypothermia when working in 

extreme weather conditions, and may incur musculo-skeletal injuries related to improper body mechanics.

Table 4-35. Leading Causes of Death by Percentage

Oregon U.S.

Cancer 23.4 24.3

Heart Disease 22.7 27.2

Cerebrovascular Disease 8.3 5.0

Chronic Lower Respiratory Disease 5.9 5.0

Accidents 4.5 6.1

Oregon numbers are from DHS (2002); U.S. numbers are from NCHS (2007).
345

Equipment operators could be injured from improperly operating the equipment or losing control of equipment on 

steep or slippery terrain. Operators and nearby workers can also suffer hearing damage. Nearby workers and the 

public can be struck by flying debris around some machinery.

The potential for hazard exposure (risk of injuries) is exacerbated when workers are fatigued, poorly trained, 

poorly supervised, or do not follow established safety practices. Appropriate training, together with monitoring 

and intervention to correct unsafe practices, would minimize risk of worker injury and illness. Compliance 

with Occupational Safety and Health Administration (OSHA) standards, along with agency, industry, and 

manufacturers’ recommendations reduces the potential exposure and risk of injury to workers. Members of the 

public are usually not at risk from manual and mechanical methods unless they are too close to machinery that is 

producing flying debris during treatment.

Statistics on injuries from herbicide application, mechanical treatment, and prescribed fire are sparse. Workrelated pilot fatalities in agriculture have a fatality rate of 70 per 100,000, third highest in the United States far 

exceeding the overall occupational fatality rate of 4 per 100,000. Only timber cutters and fishing industries have 

higher rates and these workers have fatality rates eight times the average worker rate (CDC 2004, USBLS 2008). 

Agriculture and forestry activities have among the highest injury rates (USBLS 2008). Use of chainsaws and 

mowers in mechanical treatments can lead to injuries. Likewise, prescribed fire presents hazards from inhaling 

particulates. Fatalities have been caused by prescribed fire (NIOSH 2009a).

Use of all terrain vehicles (ATVs) for herbicide application and prescribed fire has also caused injuries and 

fatalities. In response to this, BLM has conducted research to evaluate the type of vehicle, load size, slope, and to 

establish policy and training to make ATV application safer (Morin 2008). This research has been used by OSHA, 

the Consumer Product Safety Commission, and the EPA to promulgate regulations for ATV use.

Injuries from vegetation treatment are related to the percentage of acres treated by method. For instance, under 

the No Action Alternative (Alternative 2), 2 percent of acres treated are aerial application of herbicide and 32 

percent are ground application. Twelve percent of acres treated are manual or mechanical treatment and another 

12 percent of acres are treated by prescribed fire. The remaining acres are treated with bio-control, directed 

livestock, or seeding and planting.

No injuries to herbicide applicators from herbicide exposure have been recorded for at least the past five years on 

BLM lands in Oregon (Thompson, T. pers. comm.; DOI Accident Database).

Environmental Consequences

Herbicides are formulated to affect plant growth; some mimic plant hormones (auxins), others affect 

photosynthesis, amino acid, or lipid synthesis, or disrupt plant cell membranes. While they are selective for 

plants and among plants, they have the potential to affect human health if used improperly. The use of herbicides 

under a variety of application methods, as proposed in this EIS, involves potential risk or the perception of 

risk to workers and members of the public living or engaging in activities in or near herbicide treatment areas. 

Therefore, Risk Assessments were conducted to evaluate potential human health risks that could result from 

herbicide exposure both during and after treatment of public lands. See Chapter 3 and Tables 3-16 through 3-21 

for more explanation of the process and a summary of the risk categories under various exposure scenarios.

Final Environmental Impact Statement, Chapter 4: Human Health and Safety
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 346

Methodology for Assessing Effects

For the PEIS, the BLM completed Risk Assessments to evaluate potential risks to human health from exposure 

to the following five active ingredients: diflufenzopyr, diquat, fluridone, imazapic, and sulfometuron methyl. 

Diflufenzopyr was assessed only in formulation with dicamba. The remaining 12 active ingredients addressed 

in this EIS were evaluated in other Risk Assessments. The BLM relied on Risk Assessments prepared in recent 

years by the Forest Service to evaluate the risks to human health associated with ten active ingredients (2,4-

D, chlorsulfuron, clopyralid, dicamba, glyphosate, hexazinone, imazapyr, metsulfuron methyl, picloram, and 

triclopyr). For bromacil, diuron, and tebuthiuron, the BLM relied on information provided in an earlier BLM 

vegetation treatment EIS (USDI 1991), confirmed with a literature search for the PEIS.

The following sections briefly discuss the Risk Assessment methods used by the BLM in the current assessment, 

the Risk Assessment methods used by Forest Service, and the methods used by BLM in the earlier EISs. More 

detailed information on the methodology used to evaluate risks is in Appendix 8 and 13, and the Risk Assessments 

themselves are in Appendix 8.

BLM Human Health Risk Assessment Methodology (2007)

For diflufenzopyr (with dicamba), diquat, fluridone, imazapic, and sulfometuron methyl, the Risk Assessments 

followed the four-step risk assessment model identified by the National Academy of Sciences (NAS 1983)(See 

Appendix 13). These steps are: 1) hazard identification; 2) dose response assessment; 3) exposure assessment; and, 

4) risk characterization. The outcome of each of these steps is discussed below. The PEIS used herbicide toxicity 

factors from EPA that included system, neurologic, reproductive, and endocrine disrupting, and other endpoints.

An exposure assessment was conducted to predict the magnitude and frequency of potential human exposure 

to the herbicides under consideration. Both worker and public (adult and children) exposures were evaluated. 

Exposures were evaluated for applications using the maximum application rate designated by the herbicide label, 

and applications using a typical application rate that was defined by BLM.

Workers include those that mix, load, and apply herbicides and operate transport vehicles, recognizing that in 

some cases workers would perform multiple tasks, increasing his or her exposure. Both routine-use and accidental 

exposure scenarios were included in the worker evaluation. For the routine-use exposure scenario, the exposure 

assumptions were derived using information from the Pesticide Handlers Exposure Database, which is a generic 

database containing empirical dermal and inhalation exposure data for workers mixing, loading, or applying 

pesticides (EPA 1998). Accidental exposures for workers could occur via spills or direct spray onto a worker.

Two types of public use exposure scenarios are addressed:

• Potential exposure by the public during routine use of public lands to herbicide active ingredient(s) that 

have drifted outside of the area of application; and,

• Accidental scenarios where the public prematurely enters a sprayed area (a reentry scenario), is sprayed 

directly, or contacts water bodies that have accidentally been sprayed directly or into which an herbicide 

active ingredient has been spilled.

Based on consideration of potential public uses of BLM lands, and consistent with the 1991 Vegetation Treatment 

on BLM Lands in Thirteen Western States Final EIS (USDI 1991), receptors (people exposed) evaluated included 

1) hiker/hunter; 2) berry picker - child and adult; 3) angler; 4) swimmer - child and adult; 5) nearby resident - 

child and adult; and 6) American Indian - child and adult. It is assumed that the public could be exposed through 

one or more of the following exposure pathways: 1) dermal (skin) contact with spray; 2) dermal contact with 

foliage; 3) dermal contact with water while swimming; 4) ingestion of drinking water or incidental ingestion of 

water while swimming; 5) ingestion of berries; and, 6) ingestion of fish.
347

AgDrift, a computer model developed by the EPA, industry, and others was utilized to evaluate the off-site 

deposition of herbicides (SDTF 2003). The GLEAMS model was used to simulate surface runoff of the three 

terrestrial herbicides (see Appendix 8).

Forest Service Human Health Risk Assessment Methodology

The Forest Service Risk Assessment methodology (used for 2,4-D, chlorsulfuron, clopyralid, dicamba glyphosate, 

hexazinone, imazapyr, metsulfuron methyl, picloram, and triclopyr) was similar to that used by the BLM. In the 

exposure assessment phase, the Forest Service developed general and accidental exposure scenarios for workers 

expected to be handling the herbicides and for the public who could be inadvertently exposed to herbicides. 

General exposure for workers included exposure via directed foliar, broadcast ground, and broadcast aerial 

applications. Accidental exposure scenarios for workers included immersion or contaminated clothing and spills. 

Exposure scenarios for the public included: 1) direct spray; 2) dermal exposure from contaminated vegetation; 3) 

consumption of contaminated water; 4) acute exposure via spills; 5) consumption of contaminated fish; and, 6) 

consumption of contaminated vegetation.

The risk characterization process then compared the exposure assessment to the dose response assessment to 

determine a hazard quotient (HQ) for a specific exposure scenario. HQs were calculated by dividing the exposure 

level determined in the PEIS by the toxicity factor. A higher HQ indicates that the exposure level exceeds the 

toxicity factor.

BLM Human Health Risk Assessment Methodology (1991) and Toxicology Literature Review

Human health Risk Assessments for bromacil, diuron and tebuthiuron were conducted by the BLM for an earlier 

vegetation treatment EIS (USDI 1991). Literature reviews and evaluations were conducted for the period 

between 1991 to 1998 to assess whether toxicity data reported since the 1991 EIS would indicate that a new risk 

assessment should be conducted (e.g., if the new toxicity data suggested greater risks to humans) (McMullin and 

Thomas 2000). Bromacil, diuron, and tebuthiuron did not have recent toxicity data suggesting additional risks to 

humans; therefore, the human health risks of these herbicides are reported using results from the earlier EIS.

Uncertainty in the Risk Assessment Process

The Risk Assessments conducted by the BLM and Forest Service incorporate varying conservative assumptions 

to compensate for uncertainties in the risk assessment process. Within any of the steps of the human health 

risk evaluation process, assumptions must be made due to a lack of absolute scientific knowledge. Some of the 

assumptions are supported by considerable scientific evidence, while others have less support. Every assumption 

introduces some degree of uncertainty into the risk evaluation process. Regulatory risk evaluation methodology 

requires that conservative assumptions be made throughout the risk assessment process to ensure that public 

health is protected. This conservatism, both in estimating exposures and in setting toxicity levels likely led to an 

exaggeration of the real risks of the vegetation management program to ensure any uncertainty was interpreted on 

the side of protecting human health.

Effects Common to All Alternatives

Human Health Risks Associated with Herbicides Evaluated in the 2007 BLM PEIS

Tables 3-16 and 3-17 present summaries of the level of risk that workers and the public would face during 

the application of a given herbicide, for both maximum and typical application rate scenarios. Aggregated 

Risk Indices (ARIs) (see Chapter 3) are partitioned into no, low, moderate, and high levels of risk for ease 

of comparison. These designations are strictly for comparison purposes, and do not imply actual risks to 

Final Environmental Impact Statement, Chapter 4: Human Health and Safety
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 348

people because Standard Operating Procedures, PEIS Mitigation Measures, site-specific mitigation, and actual 

application and exposure scenarios would lessen exposures from Risk Assessment levels (see Standard Operating 

Procedures, PEIS Mitigation Measures, Risk, and the Potential for Adverse Effects, Chapter 3).

Diflufenzopyr: For workers, routine use ARIs were calculated for inhalation exposures under both typical and 

maximum application rate scenarios. No dermal toxicity values are available for diflufenzopyr, which, based on 

laboratory data, is not expected to be toxic through the dermal route. Routine use ARIs are greater than 1 under 

both the typical and maximum application rate scenarios, indicating no exceedance of the EPA’s LOC (see Risk 

Assessments, Chapter 3). Because the accidental worker scenarios all assume dermal exposure and diflufenzopyr 

does not have a short-term dermal NOAEL, an accidental scenario ARI was not calculated.

For the public, routine use scenario ARIs are greater than 1 under both the typical and maximum application 

rate scenarios for the public, indicating no LOC. Under the accidental scenario, it is assumed that the public is 

exposed directly to maximum herbicide application rates via dermal contact, incidental ingestion of water while 

swimming, or dietary exposure pathways at the maximum application rate. All accidental scenario ARIs are 

greater than 1, indicating risks are below the LOC.

These results indicate that exposures to diflufenzopyr are not expected to exceed the EPA’s LOC for worker or the 

public under the scenarios evaluated. Risk to aerial and boat workers were not evaluated because diflufenzopyr is 

not applied aerially or to aquatic sites. Risk to workers for accidental spill was not evaluated because there is no 

toxicity factor for oral exposure.

Diquat: PEIS Mitigation Measures (Appendix 2) limit the use of diquat to aquatic treatments, and to typical 

application rates where feasible. At the typical application rate, diquat presents a low to moderate risk to some 

workers (all backpack and horseback applicators),82 and a low risk to child residents. When diquat is applied 

at the maximum application rate, there is low to moderate83 risk to workers (except boat applicators) and the 

public (except swimmers). Diquat poses a high risk to workers and a low to moderate risk to the public under all 

accidental scenarios. Diquat causes moderate acute dermal effects and reversible eye irritation.

Fluridone: PEIS Mitigation Measures (Appendix 2) limit the use of fluridone to typical application rates, 

where feasible. Fluridone does not pose a risk to workers or the public when applied at the typical application 

rate. When fluridone is applied at the maximum application rate, there is low risk to aerial mixer/loaders. For 

accidental scenarios, fluridone poses a low to high risk to all workers, and a low risk to children and resident 

publics. Fluridone causes reversible eye irritation.

Imazapic applications do not present risk to the public or workers when applied in routine use situations at either 

the typical or maximum application rate. Accidental scenarios involving dermal contact with direct spray of 

vegetation or dietary exposure were not calculated because imazapic has not been shown to have acute dietary 

or dermal effects in hazard analyses conducted by the EPA (ENSR 2005l). Accidental scenarios involving 

dermal contact with a sprayed water body or a water body into which herbicide is spilled do not result in risk to 

swimmers. Risk to workers for accidental spill and to several public scenarios was not evaluated because there is 

no toxicity factor for oral exposure.

82 Risks to aircraft loaders are also displayed in Chapter 3, but Standard Operating Procedures preclude aerial application 

of diquat.

83 Diquat shows a high risk to workers for two aerial application scenarios, but Standard Operating Procedures prohibit 

aerial application.
349

Sulfometuron methyl applications do not present risk to human health when applied in routine use situations at 

either the typical or maximum application rate. Accidental scenarios involving dermal contact with direct spray 

of vegetation or dietary exposure were not calculated because sulfometuron methyl has not been shown to have 

acute dietary or dermal effects in hazard analyses conducted by the EPA (ENSR 2005l). Accidental scenarios 

involving dermal contact with a sprayed water body or a water body into which sulfometuron methyl is spilled do 

not present a risk to swimmers. Risk to workers for accidental spill and most public scenarios were not evaluated 

because there is no toxicity factor for oral exposure. The EPA has not developed any acute toxicity categories for 

sulfometuron methyl (EPA 2008b).

Human Health Risks Associated with Herbicides Evaluated in the 2005 Forest Service EIS84

Tables 3-18 and 4-19 present summaries of the level of risk that workers and the public would face during the 

application of a given herbicide, for both maximum and typical application rate scenarios. The Forest Service 

Risk Assessments presented the risk results as HQs, which were used to designate a risk level as no, low, 

moderate or high, for ease of comparison.

2,4-D: PEIS Mitigation Measures (Appendix 2) limit the use of 2,4-D to typical application rates, where feasible. 

At the typical and maximum application rates, workers involved in backpack spray, boom spray, and aerial 

application face low to moderate risk from 2,4-D exposure. Workers also face moderate risk from wearing 

contaminated gloves for 1 hour and no risk from exposure to a spill on lower legs for one hour or from exposure 

to spill on the hands for one hour. Based on upper bound hazard quotients that exceed 1, adverse health outcomes 

are possible for workers exposed repeatedly over a longer period. The public faces zero risk from most modeled 

scenarios at the typical and maximum application rates. Consumption of contaminated vegetation (fruit) over 

a period of several months would have a low risk to the public and a moderate risk to subsistence populations. 

Other chronic exposures to the public have no risk.

Based on recent studies reviewed by SERA, 2,4-D is toxic to the immune system and developing immune system, 

especially when used in combination with other herbicides (tank mixes). The mechanism of action of 2,4-D 

toxicity is cell membrane disruption and cellular metabolic processes. 2,4-D toxicity affects human lymphocytes 

and nerve tissue. Therefore, interactions are likely to occur when 2,4-D is mixed with other chemicals that affect 

cell membranes and cell metabolism (SERA 2006).

SERA (2006) suggests that 2,4-D may cause endocrine disruption in male workers applying large amounts of 

this herbicide; however, the study was inconclusive. Based on currently available toxicity information that 

demonstrate effects on the thyroid and gonads following exposure to 2,4-D, there are some data supporting 

its endocrine disruption potential and EPA is studying this further (EPA 2005a). In the Human Health Risk 

Assessment conducted to support the reregistration of 2,4-D (EPA 2004), the EPA concluded that there is not 

sufficient evidence that 2,4-D is an endocrine disrupting chemical. 

Chlorsulfuron: For both workers and the public, most exposures to chlorsulfuron at the typical or maximum 

application rate would not pose a risk (SERA 2004a). Ground broadcast applications at the maximum application 

rate would pose a low risk to workers.

Eye and/or skin irritation are likely to be the only overt effects of mishandling chlorsulfuron. Following industrial 

hygiene practices during the handling of the chlorsulfuron would eliminate or minimize these effects.

84 The 2,4-D Risk Assessment was updated in 2006.

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Clopyralid: There are no risks to the public or workers associated with most of the anticipated typical and 

accidental exposure scenarios for clopyralid. Irritation and damage to the skin and eyes can result from direct 

exposure to relatively high levels of clopyralid; this is likely to be the only overt effect as a consequence of 

mishandling clopyralid (SERA 2004b). Children face low risk from consumption of water contaminated by an 

accidental spill.

The human health risks of hexachlorobenzene and pentachlorobenzene were also analyzed in the Forest Service 

Human Health Risk Assessment, as technical grade clopyralid may be contaminated with these chemicals. 

Hexachlorobenzene was evaluated for potential carcinogenicity. Based on the levels of contamination of technical 

grade clopyralid with hexachlorobenzene and pentachlorobenzene, and the relative potencies of these compounds 

compared to clopyralid, this contamination is not significant in terms of potential systemic toxic effects. In 

addition, the contamination of clopyralid with hexachlorobenzene does not appear to present any substantial 

cancer risk above the Forest Service cancer risk LOC of 1 in 1 million.

Dicamba applications present low risk to workers during boom spraying. Dicamba may result in reversible eye 

irritation and severe skin irritation. There is low risk to the public from the consumption of water from a pond 

contaminated with a spill.

Glyphosate: For both workers and members of the public, there are no risks associated with nearly all exposures 

to glyphosate at the typical or maximum application rate (SERA 2003a). The Risk Assessment calculated no 

risk for all but one of the tested scenarios. There is low risk to children in the public associated with accidental 

exposure to glyphosate consumption of contaminated water after an herbicide spill into a small pond.

Endocrine disruption and glyphosate was studied by SERA in 2002. SERA reported, “Three specific tests on 

the potential effects of glyphosate on the endocrine system have been conducted and all of these tests reported 

no effects. The conclusion that glyphosate is not an endocrine disruptor is reinforced by epidemiological studies 

that have examined relationships between occupational farm exposures to glyphosate formulations and risk 

of spontaneous miscarriage, fecundity, sperm quality, and serum reproductive hormone concentrations... the 

approach taken in the Risk Assessment is highly conservative and no recent information has been encountered 

suggesting that this Risk Assessment is not adequately protective of any reproductive effects that might be 

associated with glyphosate exposure.” However, a recent study by Benachour and Seralini (2008) shows potential 

endocrine disruption, DNA damage, and toxicity of POEA and possibly alpha-amino-3-hydroxy-5-methyl-4-

isoxazolepropionic acid (AMPA, the major glyphosate degradate) in human cell cultures. This is a single study 

and scientists rely on the weight of evidence of multiple studies, which have not identified these adverse effects. 

These new findings need to be confirmed by other studies (see also the Adjuvants subsection later in this section).

Hexazinone: PEIS Mitigation Measures (Appendix 2) limit the use of hexazinone to typical application rates, 

where feasible, in addition to not allowing the application of hexazinone with an over-the-shoulder broadcast 

applicator. At typical and maximum application rates, all worker groups exposed to hexazinone may face risks, 

with the highest risks predicted for workers using an over-the-shoulder broadcast applicator (SERA 1997). 

Worker exposure is likely to exceed exposures that would generally be regarded as acceptable, if workers do 

not follow prudent handling practices that would minimize exposure. Workers exposed to hexazinone via direct 

and broadcast ground spray and aerial applications at the maximum application rate are at low risk. There 

would be a low risk associated with accidental exposure to hexazinone mixed for the maximum application rate 

via contaminated gloves (also low risk at the typical application rate) and via spills on lower legs. The most 

likely effects include irritation to the eyes, respiratory tract, and skin. Even under the most extreme exposure 

scenarios, outward toxic effects are not likely to be observed; however, the upper estimates of exposure levels 

could be associated with subclinical (non-symptomatic) effects and possible reproductive effects. In some 

accidental exposure scenarios, members of the public may face risks from exposure to hexazinone. At the typical 

application rate, there is low to moderate risk to the public associated with exposure to hexazinone under the 

following scenarios: direct spray of the entire body, acute consumption of water contaminated by a spill, and acute 
351

consumption of contaminated fish by the public and subsistence populations. For application at the maximum 

rate, the risks to the public associated with the above scenarios are low to moderate. The following additional 

scenarios pose a low risk: direct spray of the lower legs, acute and chronic consumption of fruit, and consumption 

of stream water contaminated by runoff or percolation.

Imazapyr: Most exposures to imazapyr at either the typical or the maximum application rate do not present a risk 

to either workers or members of the public, suggesting that workers and the public would generally not be at any 

substantial risk from longer-term exposure to imazapyr even at the upper range of the application rate considered 

in the Risk Assessment (SERA 2004d). Eye irritation is likely to be the only overt effect as a consequence of 

mishandling imazapyr. This effect can be minimized or avoided by prudent industrial hygiene practices during 

the handling of the compound.

Metsulfuron methyl: Typical exposures to metsulfuron methyl at the typical or maximum application rates do 

not present a risk to workers or the public (SERA 2004e). For workers, there is no risk associated with acute or 

chronic exposure scenarios, even at the upper ranges of estimated dose. For members of the public, no risks were 

predicted for any of the exposure scenarios. From a practical perspective, eye and skin irritation are likely to be 

the only overt effects of mishandling metsulfuron methyl. These effects can be minimized or avoided by prudent 

industrial hygiene practices during the handling of this compound.

Picloram: Typical exposures to picloram at either the typical or maximum application rates present few risks 

to workers or the public (SERA 2003b). For workers, no risks were predicted even at the upper ranges of 

exposure. For members of the public, no risks were predicted except for the consumption of water by a child 

following an accidental spill of a large amount of picloram into a very small pond, which presents a low risk. 

From a practical perspective, eye irritation and skin sensitization are likely to be the only overt effects as a 

consequence of mishandling picloram. Based on the standard assumptions used in this and other Forest Service 

Risk Assessments, the contamination of picloram with hexachlorobenzene does not appear to present a substantial 

cancer risk, even at the upper ranges of plausible exposure.

Triclopyr: PEIS Mitigation Measures (Appendix 2) limit the use of triclopyr to typical application rates, where 

feasible. Workers face low risk from directed and broadcast ground spray and aerial applications at the upper ranges 

of exposures for both evaluated forms of triclopyr (triclopyr acid and triclopyr BEE), at the maximum application rate 

(SERA 2003c). At the maximum application rate, workers face low risk from accidental exposure to contaminated 

gloves (1-hour duration). Thus, for workers who may apply triclopyr repeatedly over a period of several weeks 

or longer, it is important to ensure that work practices involve reasonably protective procedures to avoid the upper 

extremes of potential exposure. At higher application rates, measures that limit exposure should be developed on a 

case-by-case basis depending on the application rate and method. There is low to moderate risk to the public from 

triclopyr applications under several acute or accidental scenarios: 1) direct spray to the entire body; 2) direct spray 

to the lower legs; 3) dermal contact with contaminated vegetation; 4) acute consumption of contaminated fruit 

(maximum application rate only); and 5) acute consumption of pond water contaminated by a spill.

Human Health Risks Associated with Herbicides Evaluated in the 1991 BLM EIS

The human health risks of bromacil, diuron, and tebuthiuron were evaluated in an earlier BLM vegetation 

treatment EIS. These herbicides were not reevaluated because a literature review and evaluation showed that 

most toxicity values for these herbicides reported in more recent studies were not substantially lower (i.e., present 

more risk) than the values used to assess risks to human health in the 1991 EIS (McMullin and Thomas 2000). 

Tables 3-20 and 3-21 present summaries of the risks to workers and the public associated with these herbicides.

Bromacil: PEIS Mitigation Measures (Appendix 2) limit the use of bromacil to typical application rates, where 

feasible. According to the 1991 EIS, there would be a risk to workers associated with several exposure scenarios 

involving typical bromacil application practices. Pilots and aerial mixer-loaders face a risk for systemic, 

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reproductive, and cancer effects from typical and maximum exposures to bromacil. Backpack and hand 

applicators and ground applicators, mixer-loaders, and applicator/mixer-loaders are also at risk for systemic and 

reproductive effects from maximum exposures. Risks for systemic, reproductive, and cancer effects to workers 

and the public are associated with accidental scenarios of spill to skin (concentrate and mixture), direct spray (no 

cancer risk), consumption of fish from a directly sprayed water body (no cancer risk), consumption of directly 

sprayed berries (no cancer risk), and drinking from water contaminated by a truck spill or a jettison of mixture 

(no cancer risk). The cancer slope factor for bromacil used in the Human Health Risk Assessment was the one 

available from the EPA at the time of the 1991 EIS. However, in its most recent review of bromacil, the EPA did 

not provide a cancer slope factor (EPA 1996), therefore bromacil is likely not carcinogenic.

Diuron: PEIS Mitigation Measures (Appendix 2) limit the use of diuron to typical application rates, where feasible. 

According to the 1991 EIS, there are risks to workers and the public associated with both routine and accidental 

exposures to diuron. Aerial application poses a risk to the public for systemic effects from worst-case exposures 

(e.g., direct exposure of hikers, berry pickers, anglers, and nearby residents; spray drift to skin; vegetation contact 

by berry pickers; consumption of contaminated drinking water and fish). Berry pickers also face a risk for systemic 

effects from worst-case direct exposure and contact with vegetation scenarios. In aerial application scenarios, pilots 

and mixer-loaders are at risk for systemic and reproductive effects under both typical and worst-case exposures, 

and fuel-truck operators are at risk for systemic and reproductive effects under worst-case exposures. In addition, 

backpack and hand applicators and ground applicators, mixer-loaders, and applicator-mixer-loaders are at risk for 

systemic and reproductive effects for typical (systemic only) and worst-case exposures. There are also risks to 

workers and the public for systemic and reproductive effects associated with accidental exposures of spill to skin 

(herbicide concentrate and mixture), direct spray, drinking, or eating fish from a directly sprayed water body, or 

immediate reentry into a sprayed area by a berry picker. Diuron is a known carcinogen.

Tebuthiuron: PEIS Mitigation Measures (Appendix 2) limit the use of tebuthiuron to typical application rates, 

where feasible. According to the 1991 EIS, tebuthiuron poses health risks to workers under various application 

scenarios. Typical and worst-case aerial application exposure to tebuthiuron could result in systemic and 

reproductive effects to pilots and to mixer-loaders (no systemic risk at typical exposures). Fuel-truck operators 

could experience systemic effects from worst-case exposure to tebuthiuron during aerial application. Backpack 

applicators face systemic and reproductive risks from maximum exposures to tebuthiuron. For workers using 

ground mechanical equipment, there are systemic and reproductive risks to applicators, mixer-loaders, and 

applicator/mixer-loaders associated with worst-case exposures to tebuthiuron. Hand applicators are at risk from 

typical (reproductive effects) and worst-case (systemic and reproductive effects) exposures. Several accidental 

scenarios also pose a risk for systemic and reproductive effects to workers and the public: 1) spill of herbicide 

mixture to skin; 2) direct spray to person; 3) drinking directly sprayed water (reproductive only); 4) immediate 

reentry of a berry picker into a sprayed area; 5) consumption of directly sprayed berries; and 6) consumption of 

water contaminated by a jettison of mixture or by a truck spill.

Potential Endocrine Disrupting Chemicals 

According to the World Health Organization (2002), endocrine disrupters have been defined as exogenous 

substances that alter function(s) of the endocrine system and consequently cause adverse health effects in an 

intact organism or its progeny, or in (sub) populations. Endocrine disrupters interfere with the functioning of the 

endocrine system, in at least three possible ways: 

• By mimicking the action of a naturally-produced hormone, such as estrogen or testosterone, and thereby 

setting off similar chemical reactions in the body; 

• by blocking the receptors in cells receiving the hormones (hormone receptors), thereby preventing the 

action of normal hormones; or, 

• by affecting the synthesis, transport, metabolism, and excretion of hormones, thus altering the 

concentrations of natural hormones. 
353

During the toxicity review for the Human Health and Ecological Risk Assessments, no endocrine disrupting 

effects were noted. However, an extensive literature search revealed that diuron and 2,4-D are listed by the 

European Commission Directorate-General for the Environment (2003) as Category 2 chemicals, meaning that 

there is evidence of the potential for the listed chemical to cause endocrine disruption. Diuron only appeared 

on a single list, so there is some uncertainty within the scientific community about this herbicide’s status as an 

endocrine disruptor. 

In the Human Health Risk Assessment conducted to support the reregistration of 2,4-D (EPA 2004c), the EPA 

concluded that there is not sufficient evidence that 2,4-D is an endocrine disrupting chemical. The EPA did not 

conduct the Human Health Risk Assessment using endocrine disruption endpoints. Since the current studies that 

showed evidence of endocrine effects were tested using doses above renal saturation, the EPA recommended 

formal testing of 2,4-D for endocrine endpoints. However, there is no standard protocol for determination of 

endocrine effects of chemicals. 

Adjuvants 

Various sources of toxicity data (Muller 1980, Lewis 1991, Dorn et al. 1997, Wong et al. 1997) suggest that, for 

herbicides with high application rates, adjuvants have the potential to cause acute, and potentially chronic, adverse 

effects to aquatic species. Adjuvants and degradates were examined in the PEIS. 

The adjuvant POEA was present in the formulations of glyphosate examined in the Risk Assessment but is not 

present in all formulations. Glyphosate with POEA is potentially toxic to fish (discussed in the Fish section), 

but there is no evidence in the Risk Assessment that humans approach LOCs under any exposure scenario. A 

recent study by Benachour and Seralini (2008) shows potential endocrine disruption, DNA damage, and toxicity 

of POEA in human cell cultures. This is a single study and scientists rely on the weight of evidence of multiple 

studies, which have not identified these adverse effects. As the study itself points out, these new findings need to 

be confirmed by other studies. 

The adjuvant R-11 is a nonylphenol ethoxylate that is acutely toxic to aquatic life (Stark and Walthall 2003) and is 

suspected to be an endocrine-disrupting chemical (Bakke 2003). The Record of Decision for the PEIS suspended 

the use of R-11 in herbicide applications.

Human Health Risks by Application Method

Air: Aerial applications of herbicides generally pose a greater risk due to off-site drift than ground applications, 

as herbicides applied at greater distances from the ground are able to drift farther from the target application area. 

Therefore, risks to the public recreating or living near an application area would extend out greater distances if the 

herbicide were applied aerially than if it was applied by a ground application method. The BLM does not apply, 

sulfometuron methyl, or diflufenzopyr by air. Standard Operating Procedures specify avoiding applying bromacil 

or diuron aerially, and limiting aerial application of chlorsulfuron and metsulfuron methyl to areas with difficult 

land access.

Ground applications typically pose a lower risk to off-site humans than aerial applications because they are less 

likely to be exposed to spray drift. Similarly, spot rather than boom/broadcast applications are less likely to result in 

health risks to people downwind. However, these spot applications could present an increased risk to the workers 

charged with applying the herbicide because they are more likely to come into contact with the herbicide (their 

exposure doses is higher). In particular, workers applying diquat and 2,4-D by backpack and horseback would be at 

low to moderate risk for health risks from exposure to the herbicide. Ground boom spray applicators of 2,4-D would 

have low to moderate risk, but those applying diquat at the typical application rate by ATV or truck would not be at 

risk. In contrast, chlorsulfuron does not pose a risk to workers involved with aerial applications, but does pose a risk 

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to workers conducting ground broadcast applications at the highest application rate. Exposure to hexazinone and 

triclopyr at the maximum rate has low risk to backpack and ground boom sprayers.

Typical Application Rate

PEIS Mitigation Measures limit the use of the following herbicides to the typical application rate, where 

feasible.85 Diquat is not applied to BLM lands aerially, and poses a low risk at typical rates under some worker 

and public exposure scenarios. 2,4-D applications at the typical application rate would pose a low to moderate 

risk to plane and helicopter pilots and mixer/loaders, backpack applicator/mixer/loaders, horseback applicators 

and applicator /mixer /loaders, and consumers of contaminated fruit/vegetation. Bromacil, diuron, hexazinone, 

triclopyr, and tebuthiuron also pose a risk to the public and workers when applied at the typical application 

rate. None of the other herbicides pose a risk to people when applied at the typical application rate (Tables 3-16 

through 3-21 and Table 4-36).

Maximum Application Rate

At the maximum application rate, more herbicides, in a greater number of exposure scenarios, have greater 

potential to affect human health. Fluridone, chlorsulfuron, clopyralid, dicamba, glyphosate, picloram, and 

triclopyr do not pose a risk when applied at the typical application rate, but do pose a risk under one or more 

exposure scenarios when applied at the maximum application rate. Clopyralid, glyphosate, and picloram pose a 

low risk under the accidental scenario involving consumption of water from a small pond that has experienced a 

recent spill of herbicides mixed for the maximum application rate, which is a very unlikely scenario. In addition, 

a greater number of exposure scenarios have health risks from herbicide applications at the maximum application 

rate. Diflufenzopyr, imazapic, imazapyr, metsulfuron methyl, and sulfometuron methyl do not pose a risk to any 

humans when applied at the maximum (or typical) application rate.

Accidental Direct Spray and Spill Scenarios

Accidental direct spray and spill scenarios for many herbicides pose a risk to workers and the public (accidental 

scenarios for diflufenzopyr, imazapic, and sulfometuron methyl were not evaluated because these herbicides are 

not considered toxic through short-term dermal exposure). These scenarios are unlikely, and can be minimized 

by following Standard Operating Procedures. However, these scenarios are included on Table 4-36, Estimated 

Annual Acres of Treatments with Risk to Human Health.

Human Health Risks

Worker: 2,4-D, bromacil, diquat, diuron, and tebuthiuron pose risks to workers when applied at both typical 

and maximum application rates. Diuron poses a risk to most workers at the typical application rate. For 2,4-D, 

diquat, bromacil, and tebuthiuron, people working with aerial applications would be at low to moderate risk for 

applications at the typical application rate, and most workers would be at risk when applying these herbicides 

at maximum application rates. 2,4-D, also poses risks to ground applicators, particularly during applications at 

the maximum application rate. In addition, there are potential cancer risks to mixer/loaders of diuron. Mixer/

loaders working with aerial applications of fluridone are at low risk, and those working with bromacil, diuron, and 

tebuthiuron are at high risk when applying those herbicides at the typical and maximum application rates.

85 Standard Operating Procedures specify typical rate, where feasible, for 2,4-D, bromacil, diquat, diuron, fluridone, 

hexazinone, tebuthiuron, and triclopyr to reduce the risk to occupational and public receptors (Appendix 2).
355

Ground broadcast applicators are at risk from applying dicamba or diuron at the typical application rate, and 

bromacil, chlorsulfuron, and tebuthiuron at the maximum application rate. All workers are at risk from applying 

hexazinone, tebuthiuron, and triclopyr at the maximum application rate. The rest of the scenarios of potential 

exposure to workers were not predicted. Workers involved in the aerial application of herbicides appear to be at 

greater risk than are other workers; however, the application method that creates the most risk to workers appears 

to depend on the herbicide.

Public: In general, there are lower risks to the public than occupational workers. However, within this category, 

there is higher risk to children than adults. The public does not appear to be at risk from chlorsulfuron, diflufenzopyr, 

imazapic, imazapyr, metsulfuron methyl, or sulfometuron methyl applications (accidental scenarios were not 

evaluated for imazapic and sulfometuron methyl because these herbicides are not toxic through short-term exposure 

for specific exposure routes). Diquat application at the typical application rate poses a low risk to children. At the 

maximum application rate, diquat poses a low to moderate risk to the public, except swimmers.86 Under maximum 

application rates or accidental exposures, diuron poses a risk to the public under all treatment scenarios. In addition, 

2,4-D, bromacil, dicamba, diuron, fluridone, glyphosate, picloram, tebuthiuron, and triclopyr pose a risk to the 

public under one or more maximum application rate accidental exposure scenarios (e.g., exposure resulting from the 

spill of an herbicide into a small pond). For most herbicides (except diquat), risk to the public can be minimized or 

avoided by using the typical application rate, including other proposed mitigation measures, and following Standard 

Operating Procedures that greatly reduce the likelihood of accidents (see Standard Operating Procedures, PEIS 

Mitigation Measures, Risk, and the Potential for Adverse Effects, Chapter 3).

Summary of Highest Human Health Risks

Bromacil, diuron, diquat, and tebuthiuron have the highest health risks for workers of the 18 herbicides analyzed. 

PEIS Mitigation Measures specify avoiding applying bromacil and diuron aerially, and avoiding the maximum 

rate where feasible. Bromacil, diuron, and tebuthiuron have the highest risks to some of the public. Diuron is a 

suspected carcinogen (ENSR 2005f). 2,4-D has possible endocrine disruption abilities in workers applying large 

amounts of 2,4-D and poses moderate risks to workers performing ground-based boom spraying at maximum 

rates and under some accidental exposure scenarios.

Cumulative Human Health Risks

The human health risks from both herbicide and non-herbicide vegetation treatments are not unlike a host of other 

occupational risks throughout the west, as this section point out. The pounds of herbicide expected to be applied 

annually under future decisions implementing the Proposed Action (Alternative 4) (Table 3-4) are less than twotenths of one percent of the total pounds of pesticides applied in Oregon in 2008 (Cumulative Impacts section near 

the start of Chapter 4). Other cumulative effects are described within this section.

Effects by Alternative

As described in the Affected Environment section, there is injury/fatality risks associated with prescribed fire and 

manual and mechanical vegetation control as well as with herbicides. Aerial spraying is hazardous to pilots, but 

the hours worked in aerial spraying are far less than hours worked for ground applications per acre.

Because mechanical methods in Oregon often involve timber cutting (the most dangerous occupation in the U.S.), 

mechanical and fire methods are generally believed to be more hazardous to workers than use of herbicides.

86 Standard Operating Procedures preclude using diquat at maximum rate, or using aerial application.

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The criteria used in this section, and in Table 4-36, are: (1) relative risk of injury and disease between herbicide 

use and non-herbicide vegetation controls (e.g., mechanical and prescribed fire), (2) relative toxicity of herbicides, 

(3) acres treated, (4) mode of treatment (aerial versus ground application), and (5) population density.

Table 4-36. Estimated Annual Acres of Treatments with Risk to Worker and Public Human Health by Alternative

Herbicide or Method / Risk 

Category1

Reference 

Analysis

Alt 2

(No Action) Alt 3

Alt 4 (Proposed 

Action) Alt 5

Statewide

Estimated Annual Acres of 

Herbicide Treatments by Risk 

Category

H 0 0 0 2600 3300

M 0 8500 4000 5400 7500

L 0 4600 3200 5700 6300

0 0 9700 25700 34500 37000

Total Non Herbicide Risk Acres 8800 9200 15700 6043 5014

West of the Cascades (population density: 1 person every 6.7 acres)

Bromacil H 0 0 0 0 100

Diuron H 0 0 0 100 100

Tebuthiuron H 0 0 0 0 100

Total High Risk Acres 0 0 0 100 300

2,4-D M 0 1800 2100 2300 2300

Total Moderate Risk Acres 0 1800 2100 2300 2300

Dicamba L 0 100 200 200 200

Diquat L 0 0 0 0 100

Triclopyr L 0 0 1500 2200 2300

Total Low Risk Acres 0 100 1700 2400 2600

Total 0 Risk (Herbicides) Acres 0 5400 5600 6700 7000

Mechanical 4100 3300 3000 1248 1206

Fire 600 600 400 400 400

Total Non Herbicide Risk Acres 4700 3900 3400 1648 1606

East of the Cascades (population density: 1 person every 95.3 acres)

Bromacil H 0 0 0 900 900

Diuron H 0 0 0 1300 1300

Tebuthiuron H 0 0 0 300 800

Total High Risk Acres 0 0 0 2500 3000

2,4-D M 0 6700 1900 3100 5200

Total Moderate Risk Acres 0 6700 1900 3100 5200

Dicamba L 0 4500 800 1400 1400

Diquat L 0 0 0 0 100

Triclopyr L 0 0 700 1900 2200

Total Low Risk Acres 0 4500 1500 3300 3700

Total 0 Risk (Herbicides) Acres 0 4300 20100 27800 30000

Mechanical 1000 200 200 -7705 -8692

Fire 3100 5100 12100 12100 12100

Total Non Herbicide Risk Acres 4100 5300 12300 4395 3408

H = High, M= Moderate, and L=Low

1

 Highest risk category considering all exposure scenarios, typical rate, from Tables 3-16 through 3-21 (highest categories come from 

accidental exposure scenarios).
357

Reference Analysis – No Herbicide Use

There would be no human health risk associated with herbicide applications; risk to human health would be 

entirely from non-herbicide vegetation controls.

On the west side of the Cascades, invasive plants would be treated with mechanical methods and fire on 4,700 

acres, which is more than under any of the alternatives. Hence, risk from non-herbicide methods would be higher 

than under any of the alternatives.

On the east side of the Cascades, acres treated with mechanical and fire account for 4,100 acres. This is less than 

most alternatives.

Alternative 2 (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only

Under Alternative 2 (No Action), there would be human health risk from the application of 2,4-D and dicamba. 

2,4-D poses a moderate risk to workers, and to the public under one accidental exposure scenario, which makes 

it one of the highest risk herbicides being proposed under any alternative (of the 18 being considered). Dicamba 

poses a low risk to workers using boom sprays at the maximum application rate and to the public under one 

accidental spill scenario. The other two herbicides proposed under this alternative are generally in the no risk 

category except for some low risks under one or more accidental exposure scenarios.

On the west side of the Cascades, 1,800 acres of 2,4-D and 100 acres of dicamba would be applied, which is less 

than under any other alternative (and hence less risk). Mechanical and fire treatments would happen on 3,900 

acres, which is less than the Reference Analysis, but more than under any of the alternative (and hence more risk).

East of the Cascades, 6,700 acres of 2,4-D and 4,500 acres of dicamba would be applied. This is more acres for 

these two herbicides than under any other alternative. Mechanical and fire treatments would be the second highest 

of the alternatives (and hence the second highest risk).

Aerial application of herbicides would account for 7 percent of the application, and most or all of this would occur 

east of the Cascades.

Adverse effects (risk) can extend beyond BLM borders as cooperators attempt to match BLM herbicides on 

intermixed ownerships or cooperative use roads.

Alternative 3 – Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases

Under Alternative 3, low risk triclopyr become available.

West of the Cascades, the use of 2,4-D and dicamba would increase slightly, which, along with 1,500 acres of low 

risk triclopyr, makes this alternative slightly higher risk from herbicides than Alternative 2 (No Action). Aerial 

application would not be allowed. Acres treated with mechanical and fires would decrease, which would decrease 

risk from non-herbicide methods.

East of the Cascades, the use of 2,4-D would drop 70 percent and dicamba more than 80 percent with addition 

of herbicides categorized as no risk. Seven hundred acres of low risk triclopyr becomes available. Imazapic is 

likely to be applied aerially for 90 percent of the imazapic acres, but imazapic has a risk category of no risk, and 

would be applied in areas with low population. Aerial methods will be used to apply seven percent of the other 

Final Environmental Impact Statement, Chapter 4: Human Health and Safety
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 358

herbicides. Risk from herbicides would be lower than under any other alternative. However, mechanical and fire 

methods are expected to increase significantly, and risks from non-herbicide methods would be higher than under 

any other alternative.

Alternative 4 (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat Invasive Weeds plus Limited 

Additional Uses

West of the Cascades, under Alternative 4, diuron, which is assigned a risk category of high, becomes available. 

The use of 2,4-D would increase slightly, which, along with 100 acres of diuron and 2,200 acres of low risk 

triclopyr, makes this alternative slightly higher risk from herbicides than Alternative 2 (No Action). Aerial 

application would not be allowed. Mechanical acres drop slightly, which would slightly decrease risk from nonherbicide methods.

East of the Cascades, the use of 2,4-D would increase when compared to Alternative 3 (but still be half of the 

Alternative 2 acres), and 2,500 acres of high risk herbicides would be available, which would increase risks 

(when compared to Alternative 3)(Table 4-36). In addition, the low risk triclopyr acres would increase to 1,900. 

Imazapic would be applied aerially for 90 percent of the imazapic acres, but imazapic has a risk category of no 

risk, and would be applied in areas with low population. Aerial methods would be used to apply nearly seven 

percent of the other herbicides. Under this alternative, rights-of-way, administrative sites, and recreation sites can 

be sprayed to control native and other non-invasive vegetation, and this could result in less selective treatments 

than under Alternatives 2 and 3. However, total high and moderate risk herbicides would be be lower than 

Alternative 2 (No Action). Mechanical methods are expected to decrease significantly, and risks from nonherbicide methods would be lower than under Alternative 2 and 3, and similar to the Reference Analysis.

Alternative 5 – Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives

West of the Cascades, under Alternative 5, the low and high rated diquat, bromacil, and tebuthiuron become 

available. The use of 2,4-D would increase slightly, which, along with 100 acres of high risk diuron and 2,300 

acres of low risk triclopyr, makes this alternative higher risk from herbicides than any of the other alternatives. 

Aerial application would be allowed, but would be rare. Mechanical acres drop slightly, which would decrease 

risk from non-herbicide methods slightly.

East of the Cascades, the use of 2,4-D would increase (but still be less than under Alternative 2), and additional 

low risk triclopyr and high risk tebuthiuron would become available and the herbicide risk from the alternative 

would be the highest of any of the alternatives. Imazapic would be applied aerially for 90 percent of the imazapic 

acres, but imazapic has a risk category of no risk, and would be applied in areas with low population. Aerial 

methods will be used to apply nearly seven percent of the other herbicides. Mechanical methods are expected to 

continue to decrease, and risks from non-herbicide methods would be lowest under this alternative.
359

Final Environmental Impact Statement, Chapter 4: Critical Elements of the Human Environment

Critical Elements of the Human Environment

Air Quality Air Quality is addressed in the Air Quality section.

American 

Indian Religious 

Concerns

American Indian religious concerns are addressed in the Paleontological and 

Cultural Resources section.

Areas of Critical 

Environmental 

Concern [ACECs]

Areas of critical environmental concern are addressed in the Wilderness and Other 

Special Areas section.

Cultural 

Resources

Cultural resources are addressed in the Paleontological and Cultural Resources

section.

Energy Executive Order 13212 provides that agencies shall expedite review and...take 

action to expedite...projects that will increase the production, transmission, or 

conservation of energy. BLM Instruction Memorandum OR-2002-081 requires 

NEPA documents to contain information from which the BLM can later complete 

a Statement of Adverse Energy Impacts. Alternatives 4 and 5 would reduce 

maintenance costs by making herbicides available to treat native and other noninvasive vegetation within rights-of-ways.

Environmental 

Justice

Environmental Justice is addressed in the Environmental Justice section. 

Prime Farmlands 

or Unique Land 

Characteristics

The Farmland Protection Policy Act, (7 U.S.C. §4201 et seq.) regulates Federal 

actions with the potential to convert existing prime and unique farmlands to nonagricultural purposes. None of the action alternatives would convert farmlands. 

In fact, the alternatives would increase the likelihood of maintaining the 

productivity of such lands on or near BLM lands.

Floodplains Executive Order 11988, as amended, requires agencies to determine if a Proposed 

Action (Alternative 4) will occur in a floodplain and if the action will significantly 

affect the quality of the human environment. The objective of the law is to avoid 

adverse impacts associated with occupancy and modification of floodplains 

and to avoid floodplain development. The action alternatives themselves do 

not authorize any actions; only add tools for the control of invasive plants. By 

improving the control of invasive plants, the action alternatives could positively 

affect floodplains in ways that significantly affect the quality of the human 

environment. The potential effects of the alternatives on water flows that could 

affect floodplains are addressed in detail in the Wetlands and Riparian Areas and 

Water Resources sections.

Invasive Species EO 13112 requires the prevention of introduction of invasive species and to 

provide for their control and to minimize their economic, ecological, and human 

health impacts. The Need to which this EIS responds is, in part, to be able to 

better meet BLM’s noxious weed responsibilities, and Alternatives 3-5 seek to 

more efficiently reduce the spread of noxious weeds and other invasive plants.

Invasive and Nonnative Species

The Lacey Act of 1981, as amended, makes it unlawful to import, export, sell, 

acquire, or purchase fish, wildlife, or plants. None of the alternatives propose 

such activities.
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Noxious Weeds The Federal Noxious Weed Act of 1974, as amended, requires carrying out 

operations or measures to eradicate, suppress, control, or prevent or retard the 

spread of any noxious weed. Alternative 3 and portions of Alternatives 4 (Proposed 

Action) and 5 are specifically designed to further the objectives of this Act.

Threatened or 

Endangered 

Species

Federally Listed, Proposed, and other Special Status species of plants, fish, and 

wildlife are addressed in the Native and Other Non-Invasive Vegetation, Fish, 

and Wildlife Resources sections, and in Appendix 5, and in additional detail in the 

Biological Assessment of the PEIS, which is incorporated in this EIS. There are 

several Federally Listed fish, plants, and terrestrial animals within the analysis 

area that could potentially be affected, usually positively at least in the long term.

Wastes, 

Hazardous or 

Solid

The Resource Conservation and Recovery Act of 1976 and the Comprehensive 

Environmental Response, Compensation, and Liability Act of 1980 are laws that 

regulate hazardous waste that endangers public health or the environment. The 

alternatives propose the use of herbicides, some of which may not be applied, 

may become outdated, and may require disposal in Class I dumps. Every effort is 

made to avoid this action. Empty containers will be triple rinsed and disposed of 

in approved dumps.

Water Quality, 

Drinking or 

Ground

The Water Resources section addresses water quality and conformance with State 

water quality standards.

Wetlands/

Riparian Zones

Executive Order 11990 requires Federal agencies to avoid destruction or 

modifications of wetlands and to avoid undertaking or providing assistance for 

new construction located in wetlands. The alternatives themselves only authorize 

consideration of additional herbicides for the control of noxious weeds and other 

invasive plants in wetlands and riparian areas. These measures do not destroy, 

modify, or undertake/assist new construction located in wetlands. The action 

alternatives could variously benefit wetlands.

Wild and Scenic 

Rivers

Wild and scenic rivers are discussed in the Recreation / Interpretive Sites and the 

Wilderness and Other Special Areas sections.

Wilderness Wilderness and wilderness study areas are discussed in the Wilderness and Other 

Special Areas section.

Other Environmental Consequences

Consistent with the mandates of FLPMA and other laws and policies, the BLM and/or its cooperators manage 

vegetation on thousands of acres per year to restore forest and rangeland health; provide sustainable habitat for 

Special Status and other species of plants and animals; reduce the risk of wildland fire; and, provide for safe use 

and access to a variety of authorized developments. For these treatments, a full range of non-herbicide treatment 

methods have been analyzed in existing resource management plan (RMP) or program NEPA documents, and 

are currently in use to achieve vegetation management objectives. A portion of the vegetation management 

program is focused on the control on noxious weeds, and the tools used for the noxious weed portion of the 

program currently include the use of four herbicides. RMP direction directing the control of noxious weeds 

is compiled for reference in Appendix 6. It is in this context that the alternatives examined in this EIS are 

presented. The proposal is to increase the number of herbicides available to the nine BLM districts in Oregon 
361

Final Environmental Impact Statement, Chapter 4: Other Environmental Consequences

for use in their existing vegetation management programs. No additional types of work would be added by the 

action alternatives. Efficiency and quantity of vegetation management may go up because of selection of one of 

the action alternatives, but those effects would be within the scope of existing plans. No effects from any of the 

action alternatives, beyond those addressed within this Chapter, are anticipated.

This EIS is programmatic; individual NEPA analysis and decision-making will be made at the district and/or 

project scale to examine the potential for site-specific adverse effects. 

The Council on Environmental Quality regulations require that the discussion of environmental consequences include 

 . . . any adverse environmental effects which cannot be avoided should the proposal be implemented, 

the relationship between short-term uses of man’s environment and the maintenance and enhancement of 

long-term productivity, and any irreversible or irretrievable commitments of resources which would be 

involved in the proposal should it be implemented (40 C.F.R. 1502.16). 

Adverse Effects Which Cannot Be Avoided

Decisions made following an EIS do not have to avoid adverse effects, but the EIS must identify and disclose any 

adverse environmental, social, and economic effects. This EIS attempts to describe all identifiable adverse effects 

caused by the alternatives herein. Adverse effects, which cannot be avoided, include the likely continued spread 

of some species of noxious weed and other invasive plants at some level. The action alternatives are predicted 

to slow, but not eliminate, the adverse effects of this spread.87 For some or possibly all areas, the benefits of the 

alternatives in terms of preventing infestations of some noxious weeds, or restoring native plant communities 

infested by them, may be transitory.

There is also a low potential that the herbicide use proposed would contribute to the cumulative effect of 

herbicides, other pesticides, and other pollutants in some of Oregon’s waters. This EIS displays, in Chapter 3, the 

amount of each herbicide that would be used under the Proposed Action (Alternative 4) in the context of the total 

amount of those herbicides used statewide. The BLM could conceivably contribute to the amount of any of those 

herbicides that are found, for example, in the waters of the State. However, because of low application rates, 

streamside buffer distances and other Standard Operating Procedures and PEIS Mitigation Measures, the percent 

applied with ground methods, and the presence of environmental factors that will help hold and break down those 

herbicides, the BLM’s contribution to detectable off-site herbicide accumulations should be even lower than its 

percentage contribution to statewide totals would imply. 

Standard Operating Procedures and PEIS Mitigation Measures, as well as potential mitigation measures listed 

in Chapter 2, should make the likelihood of adverse effects low. In any event, those likelihoods are described 

in their respective sections. The possible adverse effects include health effects to persons applying herbicides, 

particularly via spills and other accidents. Although no toxicity accidents have been documented on BLM lands 

in Oregon in at least five years, they have certainly occurred in other states and could occur in Oregon in the 

future. Following prescribed procedures however, there is no evidence injury levels would significantly exceed 

those expected for industrial type work, or exceed those that would occur if the work were to be accomplished 

with non-herbicide methods.

87 Using “current budget trends” and the spread rates calculated in the Noxious Weeds and Other Invasive Plants section. 

The predicted spread rates could be incorrect, program emphasis may change, biocontrols may reduce the effect of 

weeds, and other factors outside the scope of this analysis may contribute to changes in weed spread rates in the future.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 362

Relationship Between Short-Term Uses of the Human Environment and 

Maintenance of Long-term Productivity

The Proposed Action (Alternative 4) is not an extraction or development. The action alternatives would help slow 

the spread of noxious weeds and other invasive plants, improve habitat, and make native and other non-invasive 

vegetation control more effective and efficient (and potentially less impacting) than currently-used methods. The 

Soil Resources section in this Chapter concludes that the herbicides proposed would not have permanent effects on 

the soil. Some of the herbicides are known ground-water contaminants, and PEIS Mitigation Measures are offered to 

reduce the likelihood of BLM applications polluting water. Half-lives of the herbicides under various conditions, are 

addressed in the Soil Resources and Water Resources sections; BLM-applied herbicides will break down at or near 

the point of application. The Fish section indicates BLM applications will not significantly contribute to cumulative 

downstream effects to fish. No herbicide-related effects to long-term productivity are identified. 

Long-term productivity will be affected by noxious weeds, however, either by their displacement of native plant 

communities or by their allelopathic effects on soil, so native species are displaced. These effects can last for 

years or decades. The degree to which noxious weeds remain uncontrolled will affect long-term productivity.

Irreversible or Irretrievable Impacts 

Irreversible refers to a loss of nonrenewable resources, such as mineral extraction, heritage (cultural) resources, 

or to those factors which are renewable over long time-spans, such as soil productivity. Irretrievable commitment 

applies to losses that are temporary, such as loss of forage production in an area being used as a ski run or use of 

renewable natural resources. 

The Proposed Action (Alternative 4) is not an extraction or development. The potential for damage to, or 

loss of, non-renewable cultural resources is addressed in this EIS. That portion of the analysis concluded that 

with required pre-project clearances and surveys in likely paleontological and historic areas, the likelihood of 

damaging sites during herbicide treatments was negligible. 

The spread of invasive weeds will likely cause irreversible and irretrievable impacts on many BLM sites in 

Oregon. Adverse and potentially long-term effects of noxious weed spread are documented in the analysis and 

include reductions in soil quality and wildlife habitat carrying capacity, reduced livestock and wild horse carrying 

capacity, and decreased water quality. The action alternatives would reduce, not exacerbate, these effects.

.

:
Final Environmental Impact Statement: Glossary

363

Glossary

Abiotic: Not involving living organisms.

Absorption: The process by which a chemical or other substance is able to pass through body membranes and 

enter an organism. 

Acetolactate synthase (ALS): A plant enzyme that facilitates the development of amino acids needed for plant 

growth.

Acetolactate synthase (ALS)-inhibitor: An herbicide that starves plants by reducing ALS. In this EIS, the 

ALS-inhibitors include three sulfonylureas (chlorsulfuron, metsulfuron methyl, and sulfometuron methyl) and two 

imidazolinones (imazapic and imazapyr).

Acid soil or acidic soil: A soil material having a pH of less than 7.0.

Active ingredient (a.i.): The ingredient in an herbicide that prevents, destroys, repels, desiccates, or otherwise 

controls the target plant.

Acute adverse effect level: The level at which a substance can cause adverse effects within a short time of 

dosing or exposure. 

Acute effect: An adverse effect on any living organism in which symptoms develop rapidly and often subside 

after the exposure stops. 

Acute exposure: A single exposure or multiple brief exposures occurring within a short time (e.g., 24 hours or 

less in humans). The classification of multiple brief exposures as “acute” is dependent on the life span of the 

organism.

Acute toxicity: The quality or potential of a substance to cause injury or illness shortly after exposure through a 

single or short-term exposure.

Adaptive management: A system of management practices based on clearly identified outcomes, monitoring to 

determine if management actions are meeting outcomes, and if not, facilitating management changes that will best 

ensure that outcomes are met or reevaluated. 

Additive: A substance added to another in relatively small amounts to impart or improve desirable properties or 

suppress undesirable properties. 

Additive effect: A situation in which combined effects of exposure to two chemicals simultaneously is equal to 

the sum of the effect of exposure to each chemical given alone. 

Adjuvant: A chemical that is added to the pesticide formulation to enhance the toxicity of the active ingredient 

or to make the active ingredient easier to handle. 

Administrative site: A reservation of public land for use as a site for a public buildings or other administrative 

facility. Administrative sites are generally withdrawn from public entry or mining claims and also include 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 364

any Federal lands that have been dedicated to a specified public purpose. On BLM managed lands in Oregon, 

administrative sites include, but are not limited to; seasonal fire stations, wild horse corrals, rock quarries and bulk 

material and equipment storage sites, seed orchards and related progeny test sites, other developed or improved 

sites for vegetative propagation, BLM managed airstrips and helipads, BLM range improvements and water 

source developments, sanitary systems, BLM communication sites, remote automated weather stations, etc.

Adsorption: 1) The adhesion of substances to the surface of solids or liquids. 2) The attraction of ions of 

compounds to the surface of solids or liquids. 

Adverse impact: An impact that causes harm or an undesirable result. 

Aerobic: Life or processes that require, or are not destroyed by, the presence of oxygen (Also see anaerobic).

Affected environment: Existing biological, physical, social, and economic conditions of an area subject to 

change, both directly and indirectly, as the result of a proposed human action.

Air pollutant: Any substance in the air that could, if in high enough concentration, harm humans, animals, 

vegetation, or material. Air pollutants may include almost any natural or artificial matter capable of being 

airborne in the form of solid particles, liquid droplets, gases, or a combination of these. 

Air quality: The composition of air with respect to quantities of pollution therein. Used most frequently in 

connection with “standards” of maximum acceptable pollutant concentrations. 

Algae: Simple plants containing chlorophyll. Many are microscopic, but under conditions favorable for their 

growth, they can grow in colonies and produce mats and similar nuisance masses.

Alien species: Any species, including its seed, eggs, spores, or other biological material capable of propagating 

that species that is not native to the ecosystem under consideration. Also referred to as non-natives, or exotics.

Allelopathic or allelopathy: Suppression of growth of a plant by a toxin released from a nearby plant of the 

same or another species. 

Allotment (grazing): Area designated for the use of a certain number and kind of livestock for a prescribed 

period of time. 

Alluvium: General term for clay, silt, sand, or gravel deposited in the bed of a stream during relatively recent 

geologic time as a result of stream action. 

Alternative: In an EIS, one of a number of possible options for responding to the purpose and need for action. 

Ambient air: Any unconfined portion of the atmosphere; open air, surrounding air, or “outdoor air.” 

Amphibian: Any of a class of cold-blooded vertebrates (including frogs, toads, or salamanders) intermediate in 

many characteristics between fishes and reptiles and having gilled aquatic larvae and air-breathing adults.

Amplitude: See ecological amplitude.

Anadromous fish: Fish that mature in the sea and swim up freshwater rivers and streams to spawn. Examples 

include salmon, steelhead, and sea-run cutthroat trout.
Final Environmental Impact Statement: Glossary

365

Anaerobic: Life or processes, such as the breakdown of organic contaminants by microorganisms, which take 

place without oxygen. 

Analyte: A chemical substance that is the subject of a chemical analysis.

Animal unit (AU): A standardized unit of measurement for range livestock that is equivalent to one cow, one 

horse, five sheep, five goats, or four reindeer, all over six months of age. 

Animal unit month (AUM): The amount of feed or forage required by one animal unit grazing on a pasture for 

one month. 

Anions: Negatively charged ions in solution e.g., hydroxyl or OH–ion.

Annual (plant): A plant whose life cycle is completed in one year or season. 

Anthropogenic: Caused or produced by humans.

Antifoaming agent: A type of adjuvant added to a commercial pesticide that prevents the formation of foam. 

Aquatic: Growing, living in, frequenting, or taking place in water; used to indicate habitat, vegetation, or wildlife 

in freshwater. 

Aquifer: Rock or rock formations (often sand, gravel, sandstone, or limestone) that contain or carry groundwater 

and act as water reservoirs. 

Area of Critical Environmental Concern (ACEC): An area within public lands that requires special 

management attention to protect and prevent irreparable damage to important historic, cultural, or scenic values; 

fish and wildlife resources; other natural systems or processes; or to protect life or provide safety from natural 

hazards. 

Areal: Of or relating to or involving an area.

Arid: A term applied to regions or climates where lack of moisture severely limits growth and production of 

vegetation. The limits of precipitation vary considerably according to temperature conditions. 

Arthropods: Invertebrates belonging to the largest animal phylum (more than 800,000 species) including 

crustaceans, insects, centipedes, and arachnids. Characterized by a segmented body, jointed appendages, and an 

exoskeleton composed of chitin.

Attainment area: A geographic area that is in compliance with the National Ambient Air Quality Standards. 

An area considered to have air quality as good as or better than the National Ambient Air Quality Standards as 

defined in the Clean Air Act. 

Auxin: A class of substances that in minute amounts regulate or modify the growth of plants, esp. root formation, 

bud growth, and fruit and leaf drop.

Back Country Byways: Roads designated to complement the National Scenic Byway program, featuring 

waterfalls, geology, glaciers, and rivers. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 366

Basal application: In pesticides, the placing of an herbicide on stems or trunks of plants just above the soil line.

Base: Substances that (usually) liberate OH anions when dissolved in water and weaken a strong acid.

Bedload: Rocks, pebbles, and other material in regular contact with the streambed but being moved along by it. 

Includes material moving only part of the time, as well as material rolling, sliding, etc.

Benthic: Of or relating to or happening on the bottom under a body of water.

Bequest Value: The willingness to pay or forgo something of value to ensure resources are available for use by 

future generations. This value may be expressed at the individual, group, or societal scales. 

Best management practices (BMPs): Manual-directed standard operating procedures and other standing 

direction, particularly when they apply to water.

Binder: A material used to bind together two or more other materials in mixtures. 

Bioaccumulation: The process of a plant or animal selectively taking in or storing a persistent substance. Over 

time, a higher concentration of the substance is found in the organism than in the organism’s environment. 

Biodegradation: Process of decomposition by microorganisms or other natural environmental factors. 

Biodiversity: The variety of life and its processes, including all life forms from one-celled organisms to complex 

organisms such as insects, plants, birds, reptiles, fish, other animals; and the processes, pathways, and cycles that 

link such organisms into natural communities. 

Biological assessment (BA): A document prepared by or under the direction of a federal agency. A BA 

addresses Federally Listed, species proposed for listing, and designated and proposed critical habitat that may be 

present in the action area, and evaluates the potential effects of the action on such species and habitat. 

Biological control: The use of non-native agents including invertebrate parasites and predators (usually insects, 

mites, and nematodes), and plant pathogens to reduce populations of invasive plants.

Biological crust: Thin crust of living organisms on or just below the soil surface; composed of lichens, mosses, 

algae, fungi, cyanobacteria, and bacteria. Biological crusts are typically found in arid areas.

Boom (herbicide spray): A tubular metal device that conducts an herbicide mixture from a tank to a series of 

spray nozzles. Usually mounted to a truck, or behind a tractor or all-terrain vehicle. 

Brackish: Saline water whose salt concentration is between that of freshwater and seawater (ranging from 0.5 to 

30 parts per thousand). 

Broadcast application: An application of an herbicide that uniformly covers an entire area. 

Bryophytes: Plants of the phylum Bryophyta, including mosses, liverworts, and hornworts; characterized by the 

lack of true roots, stems, and leaves.
Final Environmental Impact Statement: Glossary

367

Buffer: A solution or liquid whose chemical makeup is such that it minimizes changes in pH when acids or bases 

are added to it; a space or distance left between the application and a non-target area; a strip of vegetation that is 

left or managed to reduce the impact that a treatment or action on one area might have on another area. 

Bunchgrass: A grass having the characteristic growth habit of forming a round clump; lacking stolons or 

rhizomes. 

Bureau Sensitive: Species designated by the State Director as requiring special management consideration 

to promote their conservation and reduce the likelihood and need for future listing under the ESA. All Federal 

candidate species, proposed species, and delisted species in the 5 years following delisting are conserved as 

Bureau sensitive species, in addition to species designated by the State Director. (see also Sensitive species.)

Burn-down: Quickly stopping a plant’s progress towards seed ripening.

California Puff (CALPUFF): CALPUFF is an advanced non-steady-state meteorological and air quality 

modeling system adopted by the U.S. Environmental Protection Agency as the preferred model for assessing long 

range transport of pollutants and their impacts involving complex meteorological conditions. 

Carcinogen: A chemical capable of causing cancer. 

Carnivore: An animal that feeds on other animals, especially the flesh-eating mammals. 

Carrier: A non-pesticide substance added to a commercial pesticide formulation to make it easier to handle or 

apply. 

Carrying capacity: The maximum population of a particular species that a particular area can support without 

hindering future generations’ ability to maintain the same population. 

Cascades: A mountain range in Oregon. As used in the EIS, the Cascade crest until, at the south end of the 

state, the crest meets the Klamath County line. Then follow that line west and then south to the state line, so that 

the entire Klamath Falls Resource Area is considered east of the Cascades, and the entire Medford District is 

considered west of the Cascades. 

Cation: Positively charged ions in a solution.

Cation exchange capacity (CEC): The capacity of soil to hold nutrients for plant use. Specifically, CEC is 

the amount of negative charges available on clay and humus to hold positively charged ions. Effective cation 

exchange capacity (ECEC) is reported for acid soils (pH<5). Expressed as centimoles of charge per kilogram of 

soil (cmolc/kg). 

Chaining: Woody vegetation control that is accomplished by hooking a large anchor chain between two 

bulldozers, or one bulldozer and a weight; as the bulldozers move through the vegetation, the vegetation is broken 

or uprooted. Chaining kills a large percentage of the woody vegetation, and is often followed a year or two later 

by burning and/or seeding. 

Chloracne: An acne-like skin disorder caused by prolonged exposure to chlorinated hydrocarbons.

Cholinesterase: An enzyme found in animals that regulates nerve impulses. Cholinesterase inhibition is 

associated with a variety of acute symptoms such as nausea, vomiting, blurred vision, stomach cramps, and rapid 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 368

heart rate, paralysis, convulsions, and death.

Chemical degradation: The breakdown of a chemical substance into simpler components through chemical 

reactions. 

Chronic exposure: Exposures that extend over a long period. Chronic exposure studies are used to evaluate the 

carcinogenic potential of chemicals and other long-term health effects. 

Chronic toxicity: The ability of a substance or mixture of substances to cause harmful effects over an extended 

period, usually upon repeated or continuous exposure sometimes lasting for the entire life of the exposed 

organism. 

Cisco: Salmonid fish of the genus Coregonus that differs from other members of the genus in having upper and 

lower jaws of approximately equal length and high gillraker counts.

Class I area: Under the 1977 Clean Air Act amendments, all international parks, parks larger than 6,000 acres, 

and national wilderness areas larger than 5,000 acres that existed on August 7, 1977. This class provides the most 

protection to pristine lands by severely limiting the amount of additional air pollution that can be added to these 

areas. 

Clay: In soil, particles smaller than .002 mm in diameter.

Climate: The composite or generally prevailing weather conditions of a region throughout the year, averaged 

over a series of years. 

Code of Federal Regulations (CFR): A codification of the general and permanent rules published in the Federal 

Register by the executive departments and agencies of the federal government. 

Confidential business information (CBI): Information submitted to EPA by a pesticide registrant to fulfill 

requirements for pesticide registration that contains trade secrets or commercial or financial information that has 

been claimed as confidential by its source. EPA has special procedures for handling such information.

Conservation Strategy: See Chapter 2, Alternative 4 or http://www.fs.fed.us/r6/sfpnw/issssp. Recovery 

Plans or other plans specifically identified as part of recovery or delisting plans, Conservation Strategies, and 

Conservation Plans are collectively referred to as Conservation Strategies.

Consultation: Exchange of information and interactive discussion; usually refers to consultation mandated 

by statute or regulation that has prescribed parties, procedures, and timelines (e.g. Consultation under National 

Environmental Policy Act or Section 7 of the Endangered Species Act, or Consultation with tribes). 

Control: Eradicating, suppressing, or reducing vegetation; a population that is not exposed to the potentially 

toxic agent in toxicology or epidemiology studies.

Cooperator: Leasees, permittees, and others with authorized uses or occupancy on BLM lands.

Council on Environmental Quality (CEQ): An advisory council to the President of the United States 

established by the National Environmental Policy Act of 1969. It reviews federal programs for their effect on the 

environment, conducts environmental studies, and advises the President on environmental matters. 
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Cover: 1) Trees, shrubs, rocks, or other landscape features that allow an animal to partly or fully conceal itself. 

2) The area of ground covered by plants of one or more species, usually expressed as a percent of the ground 

surface. 

Criteria pollutants: Air pollutants designated by the U.S. Environmental Protection Agency as potentially 

harmful and for which ambient air quality standards have been set to protect the public health and welfare. The 

criteria pollutants are carbon monoxide, sulfur dioxide, particulate matter, nitrogen dioxide, ozone, hydrocarbons, 

and lead. 

Critical habitat: 1) Specific areas within a species’ habitat that are critically important to its life functions; an 

area designated by the FWS under rule-making as being critical to the needs of a federally listed species, and 

which then carries special protection and consultation requirements. 

Cultural resources: Nonrenewable evidence of human occupation or activity as seen in any area, site, building, 

structure, artifact, ruin, object, work of art, architecture, or natural feature, which was important in human history 

at the national, state, or local level. 

Cumulative effect: The effects that results from identified actions when they are added to other past, present, and 

reasonably foreseeable future actions regardless of who undertakes such other actions. Cumulative effects can 

result from individually minor but collectively significant actions taking place over a period of time.

DBH: See diameter at breast height.

Degradates: Compounds resulting from degradation.

Degradation: Physical or biological breakdown of a complex compound into simpler compounds. 

De minimus: Latin for "of minimum importance" or "trifling." Essentially it refers to something or a difference 

that is so little, small, minuscule, or tiny that it is not worth considering.

Density: The number of individuals per a given unit area. 

Detritus: Matter produced by the decay or disintegration of an organic substance.

Diameter at breast height: The diameter of the stem of a tree measured at 4.5 feet above the ground on the 

uphill side.

Diluent: An inert diluting agent added to a commercial pesticide formulation that decreases the viscosity of the 

formula. 

Dilution: The act of mixing or thinning, and therefore decreasing a certain strength or concentration. 

Direct effects: Effects on the environment that are caused by the action and occur at the same time and place. 

Directed livestock: The careful application of grazing or browsing prescriptions (i.e., specified grazing 

intensities, seasons, frequencies, livestock species, and degrees of selectivity) to achieve natural resource 

objectives. Livestock production is a secondary or nonobjective when using prescribed grazing as a natural 

resource management tool. 
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Disseminule: A reproductive plant part, such as a seed, fruit, or spore that is modified for dispersal. 

Dispersant: A type of inert ingredient added to an herbicide formulation that reduces the cohesive attraction 

between like particles. 

Dispersion: The act of distributing or separating into lower concentrations or less dense units. 

Disturbance: Events that alter the structure, composition, or function of terrestrial or aquatic habitats. Natural 

disturbances include, among others, drought, floods, wind, fires, wildlife grazing, and insects and pathogens. 

Human-caused disturbances include actions such as timber harvest, livestock grazing, roads, and the introduction 

of exotic species; also, noise or visual distractions that may displace or otherwise adversely affect wildlife. 

Dominant: A group of plants that by their collective size, mass, or number exerts a primary influence onto other 

ecosystem components; a tree whose canopy is above surrounding trees of the same age. 

Dose: The amount of chemical administered or received by an organism, generally at a given point in time. 

Dose-response: Changes in toxicological responses of an individual (such as alterations in severity of symptoms) 

or populations (such as alterations in incidence) that are related to changes in the dose of any given substance. 

Draft environmental impact statement (DEIS): The draft statement of the environmental effects of a federal 

action, which is required under Section 102 of the National Environmental Policy Act, and released to the public 

and other agencies for comment and review. 

Drift: That part of a sprayed herbicide that is moved from the target area by wind while it is still airborne. 

EC50: A concentration in air or in water that causes 50% inhibition of growth.

EC100: A concentration in air or water that causes complete inhibition of growth.

Ecological amplitude: The breadth of the biological and environmental requirements of a species such as 

temperature, moisture, soil types, hosts, and vegetation community characteristics.

Ecosystem: Includes all the organisms of an area, their environment, and the linkages or interactions among 

them; all parts of an ecosystem are interrelated. The fundamental unit in ecology, containing both organisms and 

abiotic environments, each influencing the properties of the other.

Effect: Environmental change resulting from a proposed action. Direct effects are caused by the action and occur 

at the same time and place, while indirect effects are caused by the action but are later in time, further removed in 

distance, or secondary. Effect and impact are synonymous as used in this document. 

Encroaching vegetation: Any plants growing too closely into a roadway and hampering access or visibility 

(safety) or cracking pavement; growing into power lines or structures and endangering them; growing into 

campgrounds and preventing use or diminishing enjoyment; and so forth.

Endangered species: Any species listed under the Endangered Species Act as being in danger of extinction 

throughout all or a significant portion of its range.
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Endangered Species Act (ESA): A law passed in 1973 to conserve species of wildlife and plants determined 

by the Director of the Fish and Wildlife Service or the NOAA Fisheries to be endangered or threatened with 

extinction in all or a significant portion of its range. Among other measures, ESA requires all federal agencies to 

conserve these species and consult with the Fish and Wildlife Service or NOAA Fisheries on federal actions that 

may affect these species or their designated critical habitat.

Endemic species: A species that is naturally unique to a specific locality. 

Endocrine: Referring to several glands in higher animals that secrete hormones.

Environment: 1) The physical conditions that exist within an area (e.g., the area that may be affected by a 

proposed project), including land, air, water, minerals, flora, fauna, ambient noise, and objects of historical or 

aesthetic significance. 2) The sum of all external conditions that affect an organism to influence its development 

or existence. 

Environmental assessment (EA): A concise public document that serves to document an examination of the 

potential environmental effects of a proposed project, and from that, examination documents whether to prepare 

an environmental impact statement or a finding of no significant impact. 

Environmental impact statement (EIS): A document required by the National Environmental Policy Act to 

display the significant environmental effects that may occur as a result of a federally proposed action or action 

on federal lands, and to document the examination by the responsible federal agency of consideration of a 

reasonable range of alternatives to achieve the same purpose, in order to help facilitate federal decision-making 

that minimizes unnecessary adverse environmental effects. 

Environmental justice: Equal protection from environmental hazards for individuals, groups, or communities 

regardless of race, ethnicity, or economic status. This applies to the development, implementation, and 

enforcement of environmental laws, regulations, and policies, and implies that no population of people should 

be forced to shoulder a disproportionate share of negative environmental impacts of pollution or environmental 

hazard due to a lack of political or economic strength.

Ephemeral Streams: Streams that contain running water only sporadically, such as during and following storm 

events.

Epidemiology study: A study of human population or human populations. In toxicology, a study which 

examines the relationship of exposures to one or more potentially toxic agents to adverse health effects in human 

populations. 

Eradication: Removal or elimination of a population. 

Erosion: The wearing away of the land surface by running water, wind, ice, gravity, or other geological activities.

Essential fish habitat (EFH): Waters and substrate necessary to fish for spawning, breeding, feeding, or growth 

to maturity. 

Estivation: A state of animal dormancy somewhat similar to hibernation that takes place during periods of heat 

and dryness (summer)
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Eutrophication: Excessive nutrients in a lake or other body of water, usually caused by runoff of nutrients 

(animal waste, fertilizers, sewage) from the land, which causes a dense growth of plant life; the decomposition of 

the plants depletes the supply of oxygen, leading to the death of animal life. 

Evapotranspiration: The process of transferring moisture from the earth to the atmosphere by evaporation of 

water and transpiration from plants.

Existence Values: The value held by an individual, group, or society associated with the existence of a specific 

place or resource. This typically includes market and non-market values.

Exotic species: Includes species introduced into an area; non-native species.

Extirpate: The elimination of a species from a particular area.

Extrapolation: The use of a model to make estimates of values of a variable in an unobserved interval from 

values within an already observed interval.

°F: Degrees Fahrenheit. 

Fate: The course of an applied herbicide in an ecosystem or biological system, including metabolism, microbial 

degradation, leaching, and photodecomposition. 

Fauna: The vertebrate and invertebrate animals of the area or region. 

Feasible: Capable of being accomplished in a successful manner within a reasonable period of time, taking into 

account economic, environmental, legal, social, and technological factors. 

Federally Listed: Species listed as threatened or endangered under the Endangered Species Act.

Final Environmental Impact Statement (Final EIS): A revision of the Draft Environmental Impact Statement 

based on public and agency comments on the draft; the document upon which a Record of Decision is based. 

Fire dependent: A plant or ecosystem evolving under periodic perturbations by fire and that consequently 

depends on periodic fires for normal function. 

Fire intolerant: Species of plants that do not grow well with, or die from, the effects of too much fire. 

Fire return interval: The average time between fires in a given area. 

Fire tolerant: Species of plants that can withstand a certain frequency and intensity of fire. 

Fire use: The combination of prescribed fire and wildland fire use for resource benefit to meet resource 

objectives.

First order dermal absorption: Absorption of a material (herbicide) that occurs over 24 hours. 

Fishery: The act, process, occupation, or season of taking an aquatic species. 

Flora: Plant life, especially all the plants found in a particular country, region, or time regarded as a group; a 

systematic set of descriptions of all the plants of a particular place or time.
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Fluvial: Of or relating to or happening in a river.

Forage: Vegetation eaten by animals, especially grazing and browsing animals. 

Forb: Small broad-leafed plant; broad-leaved herb other than a grass, especially one growing in a field, prairie, 

or meadow. 

Forestland: Land where the potential natural plant community contains 10% or more tree canopy cover. 

Formulation: The commercial mixture of an herbicide that includes both the active and inactive (inert) 

ingredients. 

Fragmentation (habitat): The breaking-up of a habitat or cover type into smaller, disconnected parcels.

Fuel (fire): Dry, dead parts of trees, shrubs, and other vegetation that can burn readily. 

Fugitive dust: Small dust particles that travel some distance from their point of origin; the road and trail dust 

equivalent of drift smoke.

Fungi: Molds, mildews, yeasts, mushrooms, and puffballs, a group of organisms that lack chlorophyll and 

therefore are not photosynthetic. 

Gravel: In soil, particle sizes between 2 and 64 mm in diameter.

Gross infested area or treatment area: An area of land occupied by one or more invasive plant species; the 

area of land defined by drawing a line around the general perimeter of the infestation, not the canopy cover of the 

plants; the gross area of a logical treatment unit. May contain significant parcels of land that are not occupied by 

the weed.

Groundwater: Subsurface water that is in the zone of saturation; the top surface of the groundwater is the “water 

table”; source of water for wells, seeps, and springs. 

Groundwater Contaminant: Chemical detected in ground waters. Does not necessarily infer levels are toxic or 

harmful.

Habitat: The natural environment of a plant or animal, including all biotic, climatic, and soil conditions, or other 

environmental influences affecting living conditions; the place where an organism lives. 

Half life: The amount of time required for half of a compound to degrade. 

Hazardous fuels: Living and dead and decaying vegetation that form a special threat of ignition and resistance to 

control. 

Hazard quotient (HQ): The ratio of the estimated level of exposure to a substance from a specific substance 

from a specific pesticide application to the reference dose (RfD) for that substance, or to some other index of 

acceptable exposure or toxicity. An HQ less than or equal to 1 is presumed to indicate an acceptably low level of 

risk for that specific application. Analogous to BLM risk quotient.

Herbaceous: Non-woody plants that include grasses, grass-like plants, and forbs. 
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Herbicide: A pesticide used to control, suppress, or kill vegetation, or severely interrupt normal growth 

processes. 

Herbicide resistance: Naturally occurring heritable characteristics that allow individual weeds to survive and 

reproduce, producing a population, over time, in which the majority of the plants of the weed species have the 

resistant characteristics. 

Herbivore: An animal that feeds on plants. 

Herd management areas (HMAs): Areas established for wild and free-roaming horses and burros through the 

land use planning process. The Wild Free-roaming Horse and Burro Act of 1971 requires that wild free-roaming 

horses and burros be considered for management where they were found at the time Congress passed the Act. The 

BLM initially identified 264 areas in the western U.S. as herd management areas. 

Herptiles, herps, herpetofauna: Reptiles and amphibians.

Historic Trail: See national historic trails.

Home range: The area around an animal’s established home that is visited during the animal’s normal activities. 

Hydric soil: A soil that formed under conditions of saturation, flooding, or ponding long enough during the 

growing season to develop anaerobic conditions in the upper part.

Hydrologic: The properties, distribution, and effects of water on the earth's surface, in the soil and underlying 

rocks, and in the atmosphere.

Hydrologic cycle (water cycle): The ecological cycle that moves water from the air by precipitation to the earth 

and returns it to the atmosphere; includes evaporation, run-off, infiltration, percolation, storage, and transpiration. 

Hydrolysis (chemical): Decomposition or alteration of a chemical substance by water. 

Imidazolinone: A group of herbicides that interfere with interfere with acetolactate synthase, an enzyme needed 

for plant cell growth.

Impermeable: Cannot be penetrated. 

Indigenous: Living or occurring naturally in an area; native, endemic people, flora, or fauna. 

Indirect effects: Effects that are caused by an action, but are later in time or farther removed in distance. 

Inert ingredient(s): Those ingredients that are added to the commercial product (formulation) and are not 

herbicidally active. Also called other ingredients.

Infested: An area having one or more of the subject invasive species – either plants or plant pathogens. Infested 

areas are not necessarily 100 percent infested. 

Infested Area: See gross infested area. 

Infiltration: The movement of water through soil pores and spaces. 
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375

Infrastructure: The basic facilities and installations needed for the functioning of a community or society, such 

as transportation and communications systems, water and power lines, public buildings, campgrounds, and other 

developments.

Insolation: Solar radiation received at the earth's surface.

Integrated vegetation management (IVM): A long-standing, science-based, decision-making process that 

identifies and reduces risks from vegetation and vegetation management related strategies. It coordinates the 

use of vegetation biology, environmental information, and available technology to prevent unacceptable levels 

of damage by the most economical means, while posing the least possible risk to people, property, resources, 

and the environment. IVM provides an effective strategy for managing vegetation in all arenas from developed 

agricultural, residential, and public areas to wild lands. IVM serves as an umbrella to provide an effective, all 

encompassing, low-risk approach to manage problem vegetation. A sustainable approach to managing vegetation 

by combining biological, cultural, physical, and chemical tools in a way that minimizes economic, health, and 

environmental risks.

Interagency special status/sensitive species program (ISSSSP): The BLM and FS shared program to 

coordinate record keeping and other management of the Bureau Special Status and Forest Service Sensitive 

species programs. Also, see special status species.

Intermittent stream: Any non-permanent flowing drainage feature having a definable channel and evidence of 

annual scour or deposition. This includes what are sometimes referred to as ephemeral streams if they meet these 

two criteria. 

Interspecific: Occurring between different species.

Interpretive facilities: Developed sites designed primarily to educate and provide safe access for resource 

observation, such as Adventures in the Past, Watchable Wildlife, wild horse viewing, and geologic interpretation 

sites.

Introduced species: An alien or exotic (non-native) species that has been intentionally or unintentionally 

released into an area as a result of human activity.

Invasive plants (or weeds): A non-native aggressive plants with the potential to cause significant damage to 

native ecosystems and/or cause significant economic losses. This Oregon EIS definition differs from the PEIS 

definition by not including species native to the ecosystem under consideration.

Invertebrate: Small animals that lack a backbone or spinal column, e.g. spiders, insects, and worms. 

Irretrievable commitment: A term that applies to losses of production or commitment of renewable natural 

resources. For example, while an area is used as a ski area, some or all of the potential timber production there 

is “irretrievably” lost. If the ski area closes, timber production could resume; therefore, the loss of timber 

production during the time the area is devoted to skiing is irretrievable, but not irreversible, because it is possible 

for timber production to resume if the area is no longer used as a ski area. 

Irreversible commitment: A term that applies to non-renewable resources, such as minerals and archaeological 

sites. Losses of these resources cannot be reversed. Irreversible effects can also refer to the effects of actions on 

resources that can be renewed only after a very long period of time, such as the loss of soil productivity. 
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Issue: A matter of controversy, dispute, or general concern over resource management activities or land uses. 

K Factor: In soils, a relative index of susceptibility of bare cultivated soil to particle detachment and transport by 

rainfall.

Koc: Organic carbon-water partition coefficient. 

Label: All printed material attached to or part of the pesticide container, and which contains instructions for the 

legal application of the pesticide.

Landscape: All the natural features such as grasslands, hills, forest, and water, which distinguish one part of 

the earth’s surface from another part; usually that portion of land that the eye can comprehend in a single view, 

including all of its natural characteristics. 

Large woody debris: Pieces of woody material derived from tree limbs, boles, and roots in various stages of 

decay, generally having a diameter of at least 3 inches and a length greater than 3 feet; pieces of wood that are of a 

large enough size to affect stream channel morphology. 

LC50 (median lethal concentration): A concentration of a chemical in air or water to which exposure for a 

specific length of time is expected to cause death in 50% of a defined experimental animal population.

LD50 (median lethal dose): The dose of a chemical calculated to cause death in 50% of a defined experimental 

animal population over a specified observation period. The observation period is typically 14 days. 

Leaching: The movement of chemicals through the soil by water; may also refer to the movement of herbicides 

out of leaves, stems, or roots into the air or soil. 

Lek: A traditional place where males (esp. sage grouse) assemble during the mating season and engage in 

competitive displays that attract females.

Lentic: Pertaining to or living in still water.

Level of concern (LOC): The concentration or other estimate of exposure above which there may be effects. 

Lichens: Organisms made up of specific algae and fungi, forming identifiable crusts on soil, rocks, tree, bark, 

and other surfaces. Lichens are primary producers in ecosystems. They contribute living material and nutrients, 

enrich the soil and increase soil moisture-holding capacity, and serve as food sources for certain animals. Lichens 

are slow growing and sensitive to chemical and physical disturbances. 

Listed species: Formally listed as a threatened or endangered species under the ESA. Designations are made by 

the FWS or NMFS.

Litter: The uppermost layer of organic debris on the soil surface, which is essentially the freshly fallen or 

slightly decomposed vegetation material such as stems, leaves, twigs, and fruits. 

Long-term: Generally refers to a period longer than 10 years, but it depends upon the context. 

Lowest observed adverse effect level (LOAEL): The lowest dose of a chemical in a study, or group of studies, 

that produces statistically or biologically significant increases in frequency or severity of adverse effects between 

the exposed and control populations. 
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377

Lymph: A clear fluid containing white blood cells. Lymph circulates throughout the lymphatic system, removing 

bacteria and certain proteins from body tissue. It also is responsible for transporting fat from the small intestine 

and supplying mature lymphocytes to the blood. 

Lymphatic: Pertaining to lymph, a lymph vessel, or a lymph node. 

Macrophyte: A plant, especially a marine or aquatic plant, large enough to be visible to the naked eye. 

Malignant: Cancerous.

Marsh: A type of wetland that does not accumulate appreciable peat deposits and is dominated by herbaceous 

vegetation. Marshes may be either fresh or saltwater, tidal or nontidal.

Mast: Nuts or fruits of trees and shrubs, such as beechnuts, acorns, and berries, which accumulate on the forest 

floor, providing forage for animals. 

Material safety data sheet (MSDS): A compilation of information required under the Occupational Safety and 

Health Administration Communication Standard on the identity of hazardous chemicals, health and physical 

hazards, exposure limits, and precautions. 

Maximum application rate: The maximum application rate included on the label of the formulated product. 

For example, Plateau, the formulated product that has imazapic as its active ingredient, the label states that no 

more than 12.0 fluid ounces of product are to be applied on a per acre basis. According to the label there are 

two pounds of imazapic acid equivalent in a gallon of formulated product, so the maximum amount of active 

ingredient that may be applied is 0.1875 lb. a.i./acre. 

Mechanical control: The use of any mechanized approach to control or eliminate invasive plants (i.e. mowing, 

weed whipping, or cutting with a chainsaw).

Mediterranean climate: A type of climate characterized by hot, dry, sunny summers and a winter rainy season.

Mesic: Of, characterized by, or adapted to a moderately moist habitat.

Metabolism: The sum of the chemical reactions occurring within a cell or a whole organism; includes the 

energy-releasing breakdown of molecules (catabolism) and the synthesis of new molecules (anabolism).

Microbial degradation: The breakdown of a chemical substance into simpler components by bacteria or other 

microorganisms. 

Micron: The millionth part of a meter. There are 10,000 microns in a centimeter.

Minimize: Apply best available technology, management practices, and scientific knowledge to reduce the 

magnitude, extent, and/or duration of something.

Mitigation: Actions that would: 1) avoid an impact altogether by not taking a certain action or parts of an action; 

2) minimize an impact by limiting the degree or magnitude of the action and its implementation; 3) rectify an 

impact by repairing, rehabilitating, or restoring the affected environment; 4) reduce or eliminate an impact over 

time by preserving and maintaining operations during the life of the action; and, 5) compensate for an impact by 

replacing or providing substitute resources or environments.
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Mollusks: Invertebrate animals (such as slugs, snails, clams, or squids) that have a soft unsegmented body 

usually enclosed in a calcareous shell; representatives found on BLM lands include snails, slugs, and clams.

Monitoring: The orderly collection, analysis, and interpretation of resource data to evaluate progress toward 

meeting management objectives.

Montane forests: The lower vegetation belt on mountains.

Monument: See national monument.

Morbidity: Rate of disease, injury, or illness.

Motility: Capability of motion.

Multiple uses: A combination diverse resource uses that takes into account the long-term needs of future 

generations for renewable and nonrenewable resources. These may include recreation, grazing, timber, minerals, 

watershed, wildlife, and fish, along with natural scenic, scientific, and historical values. 

Mutagenic: Capable of inducing mutation or increasing its rate.

National ambient air quality standards (NAAQS): Standards set by the U.S. Environmental Protection Agency 

for the maximum levels of pollutants that can exist in the outdoor air without unacceptable effects on human 

health or the public welfare. 

National conservation areas: Areas designated by Congress their natural, recreational, cultural, wildlife, aquatic, 

archeological, paleontological, historical, educational, and/or scientific resources and values, that are managed for 

the areas long-term conservation, protection, enhancement, and use. 

National Environmental Policy Act (NEPA): An act of Congress passed in 1969, declaring a national policy to 

encourage productive and enjoyable harmony between people and the environment, to promote efforts that will 

prevent or eliminate damage to the environment and the biosphere and stimulate the health and welfare of people, 

and to enrich the understanding of the ecological systems and natural resources important to the nation, among 

other purposes. 

National Historic Trails: Trails established to identify and protect historic routes; they follow as closely as 

possible the original trails or routes of travel of national historic significance. 

National Landscape Conservation System (NLCS): A single system that encompasses some of the BLM’s 

premier land designations such as wilderness, wild and scenic rivers, national scenic and historic trails, national 

monuments, and other designations. 

National Monument: An area designated to protect objects of scientific and historic interest by public 

proclamation of the President under the Antiquities Act of 1906, or by the Congress for historic landmarks, 

historic and prehistoric structures, or other objects of historic or scientific interest situated upon the public lands; 

designation also provides for the management of these features and values. 

National Recreation Area: An area designated by Congress to assure the conservation and protection of natural, 

scenic, historic, pastoral, and fish and wildlife values and to provide for the enhancement of recreational values. 
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379

National Recreation Trails: Trails established administratively by the Secretary of the Interior to provide for 

a variety of outdoor recreation uses in or reasonably close to urban areas. They often serve as connecting links 

between the National Historic Trails and National Scenic Trails. 

National Scenic Trails: Trails established by an Act of Congress that are intended to provide for maximum 

outdoor recreation potential and for the conservation and enjoyment of nationally significant scenic, historical, 

natural, and cultural qualities of the areas through which these trails pass. 

Native species: Species that historically occurred or currently occur in a particular ecosystem and were not 

introduced. 

Naturalized: An exotic species that now behaves like a native in that it maintains itself without further human 

intervention and is regionally widespread leading many to believe it is native.

Neurotoxins: Materials that affect nerve cells and may produce muscular, emotional, or behavioral 

abnormalities, impaired or abnormal motion, and other physiologic changes. 

Neutral: In pH terms, 7; neither acid nor basic.

Neutral soil: A soil in which the surface horizon is neither acid nor alkaline in reaction; soils with pH 6.5 to 7.5.

Neutralizer: A type of inert ingredient added to an herbicide that modifies the effect of, or counteracts the 

properties of, something within the herbicide or spray solution. 

No action alternative: The most likely condition to exist in the future if current management direction were to 

continue unchanged. 

No observed adverse effect level (NOAEL): The exposure level at which there are no statistically or biological 

significant differences in the frequency or severity of any adverse effect between the exposed and control 

populations. 

No observed effect level (NOEL): Exposure level at which there are no statistically or biological significant 

differences in the frequency or severity of any effect between the exposed and control populations. 

Non-market values: Values assigned by an individual, group, or society to goods and services that are not 

usually bought, sold, or traded. Non-market values are typically very difficult to measure.

Non-selective herbicide: An herbicide that is generally toxic to plants without regard to species or group. 

Non-target: Any organism that is not the objective of a control treatment. 

Noxious weed: A subset of invasive plants that are county, state, or federally listed as injurious to public health, 

agriculture, recreation, wildlife, or any public or private property

Nutrient cycle: Ecological processes in which nutrients and elements such as carbon, phosphorous, nitrogen, and 

others, circulate among animals, plants, soils, and air. 

O&C lands: Public lands granted to the Oregon and California Railroad Company and subsequently revested to 

the United States. O&C lands are only in Oregon, and most are managed by the BLM.
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Objective: A concise, time-specific statement of measurable planned results that respond to pre-established 

goals. An objective forms the basis for further planning to define the precise steps to be taken and the resources to 

be used to achieve identified goals. 

Obligate, as in obligate species: Required; also, exhibited by, all members of a species without exception.

Off-highway vehicle (OHV): Any motorized track or wheeled vehicle designed for cross-country travel over 

natural terrain. 

Omnivore: An animal that eats a combination of meat and vegetation. 

Option values: The willingness to pay or forgo something of value to preserve future options. This value may be 

expressed at the individual, group, or societal scales.

Oregon and California lands: Public lands in Western Oregon that were granted to the Oregon Central Railroad 

companies (later the Oregon and California Railroad Company) to aid in the construction of railroads, but that 

were later forfeited and returned to the federal government by revestment of title. 

Organic matter: Plant and animal material that is in the process of decomposing.

Paleontological resources: A work of nature consisting of or containing evidence of extinct multicellular beings 

and includes those works or classes of works of nature designated by the regulations as paleontological resources. 

Paleontology: A science dealing with the life of past geological periods as known from fossil remains.

Parent material: The unconsolidated and more or less chemically weathered mineral or organic matter from 

which the soil has developed by pedogenic processes. 

Particulate matter (PM): A complex mixture consisting of varying combinations of dry solid fragments, solid 

cores with liquid coatings, and small droplets of liquid. These tiny particles vary greatly in shape, size, and 

chemical composition, and can be made up of many different materials such as metals, soot, soil, and dust. 

Particulates: Solid particles or liquid droplets suspended or carried in the air. 

Pathogen: An agent such as a fungus, virus, or bacterium that causes disease. 

Perennial: A plant with a life cycle lasting more than two years; a stream that flows year round.

Periphyton: A complex matrix of algae and heterotrophic microbes attached to submerged substrata in almost all 

aquatic ecosystems. 

Permit: A revocable authorization to use public land for a specified purpose. 

Persistence: The length of time a compound, once introduced into the environment, stays there. 

Pesticide: Any substance used for controlling, preventing, destroying, repelling, or mitigating any pest. Includes 

fungicides, herbicides, fumigants, insecticides, nematicides, rodenticides, desiccants, defoliants, plant growth 

regulators, and so forth. Any material used in this manner is a pesticide and must be registered as such, even if it 

has other non-pesticide uses. 
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Petroglyph: An image recorded on stone, usually by prehistoric peoples, by means of carving, pecking, or 

otherwise incised on natural rock surfaces. 

Pictograph: A symbol that represents an object or a concept by illustration. 

pH: A measure of how acidic or alkaline (basic) a solution is on a scale of 0 to 14 with 0 being very acidic, 14 

being very alkaline, and 7 being neutral. The abbreviation stands for the potential of hydrogen. 

Photodegradation: The photochemical transformation of a molecule into lower molecular weight fragments, 

usually in an oxidation process. This term is widely used in the destruction (oxidation) of pollutants by 

ultraviolet-based processes. 

Photolysis: Chemical decomposition induced by light or other radiant energy. 

Phytotoxicity: The ability of a material such as a pesticide or fertilizer to cause injury to plants. 

Piscivore: Animal that feeds on fish. 

Plant: Any of various photosynthetic, eukaryotic (meaning an organism with cells having a distinct nucleus), 

multicellular organisms of the kingdom Plantae characteristically producing embryos, containing chloroplasts, 

having cellulose cell walls, and lacking the power of locomotion. For purposes of this EIS, the term “plant” does 

not include fungi.

Plant community: A vegetation complex, unique in its combination of plants, which occurs in particular 

locations under particular influences. A plant community is a reflection of integrated environmental influences on 

the site, such as soils, temperature, elevation, solar radiation, slope aspect, and precipitation. 

Playas: Flat land surfaces underlain by fine sediment or evaporate minerals deposited from a shallow lake on the 

floor of a topographic depression. 

PM2.5: Fine particulates that measure 2.5 microns in diameter or less. 

PM10: Particulate matter that measures 10 microns in diameter or less. 

Porosity: The ratio of the volume of void space in a material (e.g., sedimentary rock or sediments) to the volume 

of its mass. 

Post-emergent (herbicide): Herbicide used to kill weeds after they have germinated and are growing. 

Potable water: Water that is considered safe for drinking and cooking.

Potential vegetation type: The combination of species that could occupy the site in the absence of disturbance. 

Predator: An animal that exists by preying on other animals. 

Pre-emergent (herbicide): A soil applied herbicide used to keep seeds from germinating.

Preferred alternative: The alternative identified in an EIS as best resolving the problems identified in the 

purpose and need. 
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Prescribed fire: A wildland fire that burns under specified conditions and in predetermined area, to produce the 

fire behavior and fire characteristics required to attain resource management objectives.

Prevention: To detect and ameliorate conditions that cause or favor the introduction, establishment, or spread of 

invasive organisms or conditions.

Prevention of significant deterioration (PSD): A U.S. Environmental Protection Agency program in which 

state and/or federal permits are required in order to restrict emissions from new or modified sources in places 

where air quality already meets or exceeds primary and secondary ambient air quality standards. 

Primary productivity: The process by which organisms make their own food from inorganic sources. The 

majority of primary producers are terrestrial plants and microbial life, such as algae. These organisms are known 

as autotrophs, since they can use inorganic substrates and solar energy to carry out metabolic processes and build 

cellular material. Primary productivity due to photosynthesis is commonly measured by quantifying oxygen 

production or CO2 assimilation.

Productivity: The innate capacity of an environment to support plant and animal life over time. Plant 

productivity is the rate of plant production within a given period of time.

Productive soil: Soil with the capacity of a soil to produce plant growth, due to the soil’s chemical, physical, and 

biological properties.

Programmatic EIS: An EIS that examines the area-wide effects of a proposal to adopt area-wide direction. 

Progeny test site: A test area for evaluating parent seed trees by comparing the growth of their offspring 

seedlings.

Propagule: A structure such as a cutting, a seed, or a spore, that can produce a plant.

Proper functioning condition: The condition of riparian and wetland areas when adequate vegetation, landform, 

or large woody debris are present to dissipate stream energy associated with high water flows. This reduces 

erosion and improves water quality; filters sediment, captures bedload, and aids in floodplain development; 

improves floodwater retention and groundwater recharge; develops root masses that stabilize streambacks against 

cutting; develops diverse ponding and channel characteristics to provide habitat and water depth, duration, 

and temperature necessary for fish production, avian breeding habitat, and other uses; and supports greater 

biodiversity. 

Proposed action: A proposal by a federal agency to authorize, recommend, or implement an action. 

Proposed threatened or endangered species: Plant or animal species proposed by the U.S. Fish & Wildlife 

Service to be biologically appropriate for listing as threatened or endangered and that is published in the Federal 

Register. It is not a final designation. Proposed species are, at minimum, managed as Bureau Sensitive until a 

decision is made about federal listing. 

Public domain lands: One category of public lands that have never left federal ownership (as opposed say, to 

the O&C lands); also, lands in federal ownership that were obtained by the government in exchange for public 

domain lands or for timber on public domain lands. 
Final Environmental Impact Statement: Glossary

383

Public lands: Any land and interest in land owned by the United States that are administered by the Secretary 

of the Interior through the BLM, without regard to how the United States acquired ownership, except for 1) 

lands located on the Outer Continental Shelf, and 2) lands held for the benefit of American Indians, Aleuts, and 

Eskimos. Includes public domain and acquired lands. 

Public purpose lease: Public lands leased to State and local governments and to qualified nonprofit organizations 

for recreation and public purposes such as historic monument sites, campgrounds, schools, firehouses, law 

enforcement facilities, municipal facilities, landfills, hospitals, parks, and fairgrounds. Authority is under the 

Recreation and Public Purposes Act, 68 Statute 173; 43 United States Code 869 et. Seq., and administered by the 

BLM under regulations at 43 CFR Part 2912.

Public scoping: See scoping.

Pumped storage hydro-power: A high and low lake system connected by pump/turbines that can generate 

electricity from falling water during high electrical use periods, and then reverse to pump the water back up using 

alternative sources of electricity during low electrical use periods, such as at night.

Qualitative: Traits or characteristics that relate to quality and cannot be readily measured with numbers or for 

which the numbers are unknown and would be difficult to obtain with any precision. 

Quantitative: Traits or characteristics that can be measured with numbers. 

Radiorespirometric: Of, relating to, or being a study of metabolism by the measurement of carbon dioxide 

labeled with carbon 14 from the carbohydrate substrate.

Rangeland: Land on which the native vegetation is predominantly grasses, grass-like plants, forbs, or shrubs; not 

forests. 

Raptor: Bird of prey; includes eagles, hawks, falcons, and owls. 

Ratepayer: A utility subscriber whose monthly bill goes in part to (and is thus affected by) maintaining the 

generating and/or distribution system across public lands, be it power or phone lines, pipe lines, cell phone 

towers, wind mills, etc. 

Receptor: An ecological entitysuch as a person, fish, plant, or slug exposed to a stressor such as an herbicide 

dose. 

Record of decision (ROD): A document separate from, but associated with, an EIS, which states the decision, 

describes why it was selected from among the alternatives, specifies which is environmentally preferable 

alternative, and states whether all practicable means to avoid environmental harm from the alternative have been 

adopted, and if not, why not. 

Recovery plan: A plan for the conservation and survival of an endangered or threatened species listed under the 

Endangered Species Act. The plan's purpose is to improve (recover) the status of the species so it no longer needs 

Federal Listing. 

Recreation Area: See national recreation area.

Recreation Trails: See national recreation trails.
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Reducing or reduced soil conditions: Conditions that deplete or remove oxygen and where anaerobic processes 

dominate.

Reference dose (RfD): An estimate of a daily oral exposure to the human population (including sensitive 

subgroups) that is likely to not result in an appreciable risk of deleterious effects during a lifetime. It is derived 

from the no-observed-adverse-effect-level, the lowest-observed-adverse-effect-level, or a benchmark dose. 

Uncertainty factors are applied when developing the reference dose so the RfD incorporates additional protection 

to account for the range of uncertainties in the data used. 

Registered herbicide: All herbicides sold or distributed in the United States must be registered by the U.S. 

Environmental Protection Agency. Registration requires scientific studies showing that the material can be used 

without posing unreasonable risks to people or the environment. 

Research natural areas (RNAs): Parts of a national network of reserved areas under various ownerships, 

containing important ecological and scientific values and are managed for minimum human disturbance. They are 

established and managed to protect ecological processes, conserve biological diversity, and provide opportunities 

for observation for research and education.

Resident fish: Fish that spend their entire life in freshwater (e.g., bull trout) on or near a specific location. 

Residue: Herbicide or its metabolites remaining in or on soil, water, plants, animals, or surfaces. 

Resilience: The ability of a system to respond to disturbances without long-term adverse effects to the 

functioning of the system; the ability of a community to respond to externally induced changes such as larger 

economic forces. 

Resource management plan (RMP): A plan for a BLM district or portion of a district that provides for public 

land use. The Plan must observe the principles of multiple use and sustained yield, use an interdisciplinary 

approach, give priority to the designation and protection of areas of critical environmental concern, consider 

present and future uses, consider scarcity of the values involved, and appropriately integrate with other federal 

plans and pollution control laws.

Restoration: Actions taken to move a degraded ecosystem back toward desired, healthy, and functioning 

conditions and processes. 

Revegetation: Establishing or re-establishing desirable plants where desirable plants are absent or of inadequate 

density, either by controlling site conditions (including the suppression of unwanted competition) so existing 

vegetation can reseed and spread, or by direct seeding or transplanting. 

Right-of-way (ROW): A permit or an easement that authorizes the use of lands for certain specified purposes, 

such as the construction of forest access roads, gas pipelines, or power lines. 

Rill erosion: An erosion process in which many small channels a few centimeters deep are formed. It occurs 

mainly on recently denuded soils. 

Riparian area: Those terrestrial areas where the vegetation complex and microclimate conditions are products of 

the combined presence and influence of perennial and/or intermittent water, associated high water tables, and soils 

that exhibit some wetness characteristics. Normally used to refer to the zone within which plants grow rooted in 

the water table of these rivers, streams, lakes, ponds, reservoirs, springs, marshes, seeps, bogs, and wet meadows.
Final Environmental Impact Statement: Glossary

385

Risk: The likelihood that a given exposure to an item or substance (e.g. herbicide dose) will produce illness or injury. 

Risk assessment: The process of gathering data and making assumptions to estimate short- and long-term 

harmful effects to human health or elements of the environment from particular products or activities. See 

Appendix 8. 

Risk quotient (RQ): The Estimated Environmental Concentration (EEC), as calculated through computer 

modeling, divided by the LD50 (lethal dose where 50% of test population dies) or LC 50 (lethal concentration for 

aquatic forms, where 50% of the test population dies). RQs were developed to provide a more realistic scenario 

of herbicide exposure. Even so, results assume 100 percent exposure and animals confined to the treatment 

area. For species that are at all mobile, such exposures are unlikely from the applications proposed by the action 

alternatives. Analogous to Hazard Quotient. An RQ less than or equal to 1 is presumed to indicate an acceptably 

low level of risk for a specific application.

Risk quotient: The lowest reported acute statistical endpoint (e.g. NOAEL, LOEAL) or Toxicity reference value 

(TRV) divided by the estimated exposure concentration (ECC). See Chapter 3, High, Medium, and Low Risk in 

BLM and FS Risk Assessments.

Runoff: Overland flow; that part of precipitation, as well as any other flow contributions that does not soak into 

soil or stay held on the site for evaporation or transpiration, but runs into streams.

Salmonids: Fishes of the family Salmonidae, including salmon, trout, chars, whitefish, ciscoes, and grayling. 

Sand: In soil, particles .05 to 2 mm in diameter. 

Savannah: Areas with canopy cover (generally dominated by oaks) less than 30 percent, and grass dominated 

understory. 

Scenic trails: See national scenic trails.

Sclerophyllous: Hard-leaved evergreen shrubs that are adapted to hot summers.

Scoping: A process at the beginning of a NEPA analysis whereby the public is asked to provide oral or written 

comments about the scope of the analysis and the range of alternatives, to help ensure the analysis appropriately 

addresses potential effects on individuals, communities, and the environment.

Sediments: Unweathered geologic materials generally laid down by or within water bodies; the rocks, sand, 

mud, silt, and clay at the bottom and along the edge of lakes, streams, and oceans. 

Sedimentation: The process of forming or depositing sediment; letting solids settle out of wastewater by gravity 

during treatment. 

Seed orchard: A plantation of clones or seedlings from selected trees; isolated to reduce pollination from outside 

sources; weeded of undesirables; and cultured for early and abundant production of seed.

Selective herbicide: A chemical designed to affect only certain groups or types of plants, leaving other tolerant 

plants unharmed. 

Semi-arid: Moderately dry; region or climate where moisture is normally greater than under arid conditions, but 

still limits the production of vegetation. 
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Sensitive species (Bureau Sensitive): Native species designated by the state director as sensitive because 

they are found on BLM-administered lands for which the BLM has the capability to significantly affect the 

conservation status of the species through management, and either: 1. There is information that a species has 

recently undergone, is undergoing, or is predicted to undergo a downward trend such that the viability of the 

species or a distinct population segment of the species is at risk across all or a significant portion of the species 

range, or 2. The species depends on ecological refugia or specialized or unique habitats on BLM-administered 

lands, and there is evidence that such areas are threatened with alteration such that the continued viability of the 

species in that area would be at risk (USDI 2008d). See also Bureau Sensitive.

Seral: Pertaining to the sequence of ecological communities successively occupying an area from the initial stage 

to the climax.

Sheet erosion: The removal of a fairly uniform layer of soil from the land surface by runoff water.

Short-term effects: Effects occurring during or shortly after project implementation and normally ceasing or 

recovering within hours to weeks, depending upon the resource. 

Shrub steppe vegetation: See Sagebrush Steppe Biome description near the beginning of Chapter 4.

Significant: The description of an impact that exceeds a certain threshold level. Requires consideration of both 

context and intensity. The significance of an action must be analyzed in several contexts, such as society as a 

whole, and the affected region, interests, and locality. Intensity refers to the severity of effects, which should be 

weighed along with the likelihood of its occurrence. Determination of significance for effects is a management 

decision considering multiple factors, and not one made by technical specialists to indicate the quantity of effects 

are above or below some level.

Silt: In soil, particles between .002 and .05 mm in diameter.

Site-specific: At the site, area, or project level.

Socioeconomic: Pertaining to, or signifying the combination or interaction of social and economic factors. 

Soil compaction: The compression of the soil profile from surface pressure, resulting in reduced air space, lower 

water holding capacity, and decreased plant root penetrability. 

Soil horizon: A layer of soil material approximately parallel to the land surface that differs from adjacent 

genetically related layers in physical, chemical, and biological properties. 

Special status species: Federally Listed threatened, endangered, proposed, or candidate species, and species 

managed as sensitive species by the BLM. 

Species: A group of organisms all of which have a high degree of physical and genetic similarity, generally 

interbreed only among themselves, and show persistent differences from members of allied groups of organisms.

Spot treatment: An application of an herbicide to a small selected area such as an individual plant, as opposed to 

a broadcast application. 

Stabilizer: A type of inert ingredient added to a commercial pesticide that makes the mixture more stable. 
Final Environmental Impact Statement: Glossary

387

Stand: A group of trees, shrubs, or grasses in a specific area that is sufficiently alike in composition, age, 

arrangement, and condition so as to be distinguishable from the vegetation in adjoining areas. 

Standard operating procedures (SOPs): Procedures that would be followed by the BLM to ensure that risks to 

human health and the environment from treatment actions were kept to a minimum. See Appendix 2. Since they 

originate from Manual and other direction, they may appear in resource management and other plans under other 

titles. SOPs specific to water are usually referred to as best management practices (BMPs).

Step-down: The process of applying broad-scale science findings and land use decisions to site-specific areas 

using a hierarchical approach of understanding current resource conditions, risks, and opportunities. 

Stressor: Any event or situation that precipitates a change. 

Subalpine: A terrestrial community that generally is found in higher elevation harsher environments than the 

montane terrestrial community. Subalpine communities are generally colder than montane and support a unique 

clustering of plant and wildlife species. 

Subchronic toxicity: The ability of the substance to cause effects for more than one year but less than the 

lifetime of the exposed organism. 

Subchronic: The effects observed from doses that are of intermediate duration, usually 90 days. 

Subsistence: Customary and traditional uses of wild renewable resources (plants and animals) for food, shelter, 

fuel, clothing, tools, etc. 

Substantive: Possessing substance; having practical importance, value, or effect. 

Succession: The change in structure and composition of plant and animal communities over time. Usually 

used to describe the advancement of a younger, pioneering community to an older differing in species age, 

composition, and processes, and thus may be reset by fire or other disturbance.

Sulfonylurea: A group of herbicides that interfere with interfere with acetolactate synthase, an enzyme needed 

for plant cell growth.

Surface water: Water naturally open to the atmosphere (rivers, lakes, reservoirs, streams, impoundments, seas, 

estuaries, etc.) and all springs, wells, or other collectors that are directly influenced by surface water.

Surfactant: A material that improves the emulsifying, dispersing, spreading, wetting, droplet size, or other 

surface-modifying properties of liquids. 

Surrogate: A substitute or stand-in. 

Synergistic: A type of cumulative effect where total effect is greater than the sum of the effects taken 

independently. 

T Factor: The tolerable amount of soil loss (tons per acre per year) prior to reduced productivity.

Tank mixture: The mixture of two or more compatible herbicides in a spray tank in order to apply them 

simultaneously. 
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Target species: A species (in this EIS, a plant species) that is a target or goal of a treatment or control effort. 

Teratogenic: Causing structural defects that affect the development of an organism; causing birth defects. 

Terrestrial: Of or relating to the earth, soil, or land; inhabiting the earth or land. 

Threatened species: A plant or animal species federally listed as threatened under the Endangered Species Act, 

and status defined as likely to become an endangered species throughout all or a significant portion of its range 

within the foreseeable future. 

Threshold: A dose or exposure below which there is no apparent or measurable adverse effect. 

Tier: Incorporating by reference the analyses in an EIS or similar document of a broader scope. For example, 

BLM field offices could prepare environmental assessments for local projects that tier to this EIS. 

Tolerable soil loss: The maximum annual amount of soil which can be removed before the long-term natural soil 

productivity is adversely affected.

Tolerances: EPA limits on the amount of a pesticide permitted in foods or drinking water.

Total suspended particles (TSP): A method of monitoring airborne particulate matter by total weight. 

Toxicity: A characteristic of a substance that makes it injurious. 

Toxicity reference value (TRV): A quantitative benchmark. For each herbicide, receptor, and route of exposure, 

the lowest reported acute statistical endpoint was selected as the Acute TRV.

Traditional use areas (Native American plant gathering): Areas where tribes continue to gather plant materials 

for food, basketry, and other traditional uses. These may or may not be treaty reserved rights and/or areas.

Transpiration: Water loss from plants during photosynthesis. 

Treaty resources: Resources for which one or more tribes have treaty rights. An exhaustive list does not exist, 

because American Indian tribes maintain confidentiality for names of medicines or spiritual plants and other 

natural resources.

Treaty rights: Tribal rights or interests reserved in treaties, by American Indian tribes for the use and benefit of 

their members. The uses include such activities as described in the respective treaty document. Only Congress 

may abolish or modify treaties or treaty rights.

Tribe: Term used to designate any American Indian band, nation, or other organized group or community, which 

is recognized as eligible for the special programs and services provided by the U.S. to American Indians because 

of their status as Indians. 

Trophic: Of or pertaining to nutrition; concerned in nutritive processes.

Trust land: Any land in collective tribal holding or individual ownership for which the Secretary of the Interior 

has a continuing responsibility to manage in a manner to benefit the respective tribe or individual. The most 

common example is forested acres on a reservation. Some Trust lands were set aside as compensation for claims 

made against the Government; most of which are off-reservation.
Final Environmental Impact Statement: Glossary

389

Typical rate or typical application rate: One of two application rates considered in many Risk Analyses (the 

other being Maximum Rate); a rate based upon a general summary of actual applications that have been made of 

the different formulations of a particular active ingredient on BLM lands. Under some situations, this value may 

be higher or lower than what is going to be applied for a specific job. The rate of application of any pesticide is 

based upon several factors, including, but not limited to, the species to be controlled, the environment for which 

the application is to be made, the timing of the application, and other factors. For example, a typical rate of 

application for imazapic is about 2.0 fluid ounces of Plateau, which, when taking into the concentration of the 

formulated product (2.0 pounds acid equivalent/per gallon) equates to 0.0313 lb. a.e./acre. It is known that 2.0 

fluid ounces of Plateau will achieve a specific level of control under a specific set of conditions. Rates around 

4.0 to 6.0 fluid ounces of imazapic appear to be the more common range for activity, based on the experience 

of researchers, for downy brome. The rate is based upon what is identified as what is normally considered for 

application under a normal condition. See Background for Effects Analysis in Chapter 3 for table of amounts of 

a.e./acre.

Uncertainty factor: A multiplier used in risk assessments to compensate for unknown risks due to limitations in 

the research.

Understory: Plants that grow beneath the canopy of other plants. Usually refers to grasses, forbs, and low 

shrubs under a tree or shrub canopy. 

Upland: The portion of the landscape above the valley floor or stream.

Urticaria: A transient condition of the skin usually caused by an allergic reaction, characterized by pale or 

reddened irregular, elevated patches and severe itching; hives.

Utility corridor: A linear strip of land identified for the present or future location of utility lines.

Vascular plants: Plants that have specialized tissues that conduct nutrients, water, and sugars along with other 

specialized parts such as roots, stems, and reproductive structures. Vascular plants include flowering plants, ferns, 

shrubs, grasses, and trees. 

Vertebrate: An animal with a backbone, such as fish, amphibians, reptiles, birds, and mammals. 

Visual resources: The visible physical features of a landscape. 

Vitiligo: A skin disorder characterized by smooth, white patches on various parts of the body, caused by the loss 

of the natural pigment.

Volatilization: The conversion of a solid or liquid into a gas or vapor; evaporation of herbicide before they are 

bound to a plant or ground. 

Water quality: The interaction between various parameters that determines the usability or non-usability of 

water for on-site and downstream uses. Major parameters that affect water quality include temperature, turbidity, 

suspended sediment, conductivity, dissolved oxygen, pH, specific ions, discharge, and fecal coliform. 

Watershed: The region draining into a river, stream, or body of water. 

Weed: A plant considered undesirable and that interferes with management objectives for a given area at a given 

point in time. 
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Wetlands: Those areas that are inundated or saturated by surface water or groundwater at a frequency and 

duration sufficient to support, and that under normal circumstance do support, a prevalence of vegetation typically 

adapted for life in saturated soil conditions. Wetlands include habitats such as swamps, marshes, and bogs. 

Wild and scenic rivers: Rivers designated in the National Wild and Scenic Rivers System that are classified in 

one of three categories (wild, scenic, or recreational), depending on the extent of development and accessibility 

along each section. In addition to being free flowing, these rivers and their immediate environments must possess 

at least one outstandingly remarkable value: scenic, recreational, geologic, fish and wildlife, historical, cultural, or 

other similar values. 

Wilderness: Land designated by Congress as a component of the National Wilderness Preservation System. 

Characteristics qualifying an area for wilderness are: 1) naturalness - lands that are natural and primarily affected 

by the forces of nature; 2) roadless and having at least 5,000 acres of contiguous public lands; and 3) outstanding 

opportunities for solitude or primitive and unconfined, non-motorized types of recreation. In addition, areas may 

contain “supplemental values,” consisting of ecological, geological, or other features of scientific, educational, 

scenic, or historical importance. 

Wilderness study area: An area managed so as not to impair its suitability as wilderness, while Congress 

determines whether to designate it as wilderness.

Wildfire: An unwanted wildland fire. 

Wildland fires: Fires occurring on wildlands, regardless of ignition source, damages, or benefits, and including 

wildfire and prescribed fire. 

Wildland urban interface (WUI): An area where structures and other human development intermingle with 

undeveloped wildlands or vegetative fuels. 

Woodland: Areas with oak or other hardwoods occupying greater than 30 percent canopy cover, generally 

forming only an open canopy with the intervening area being occupied by lower vegetation, commonly grass.

Xeric: Very dry region or climate; tolerating or adapted to dry conditions (e.g. desert). 
Final Environmental Impact Statement: References

391

References

References included here are specific to Chapters 1-4. References sections are also included in many of the appendices.

As Cited Citation

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Allen and West 1993 Allen, E.B., and N.E. West. 1993. Nontarget Effects of the Herbicide Tebuthiuron on 

Mycorrhizal Fungi in Sagebrush Semidesert. Mycorrhiza 3:75-78. pp 46-53.

American Cyanamid 

1986

American Cyanamid. 1986. Arsenal Herbicide: Technical Report. American Cyanamid 

Agricultural Division. Madison, New Jersey.

Anderson and Inouye 

2001

Anderson, Jay. E. and Richard S Inouye. 2001. Landscape-scale changes in plant species 

abundance and biodiversity of a sagebrush steppe over 45 years. Ecological Monographs 

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Appiah et al. 2004

Appiah, A.A., P. Jennings and J.A. Turner. 2004. Phytophthora ramorum: one pathogen and 

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Archer 2001 

Archer, Amy J. 2001. Taeniatherum caput-medusae. In: Fire Effects Information System, 

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Asher 2000 Asher, J. 2000. War on Weeds: Winning it for Wildlife. Transactions of the Sixty-fifth North 

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Asher and Spurrier 

1998

Asher, Jerry, and C. Spurrier. 1998. “The Spread of Invasive Weeds in Western Wildlands: 

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Atzet et al. 1996. 

Atzet, T., White, D.E., McCrimmon, L.A., Martinez, P.A., Fong, P.R., and Randall, V.D. 

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Austin et al. 1991 

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(Glyphosate) on Periphyton Communities Developed in Experimental Streams. Bulletin of 

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Bachelet et al. 2001

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Bailey 1998

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Bakke 2003 Bakke, David. 2003. Analysis of Issues Surrounding the Use of Spray Adjuvants With 

Herbicides. Pacific Southwest Research Station, USDA Forest Service, Albany, CA.

Barbash et al 1999

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Barker et al. 1998

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Barney and 

Frischknecht 1974

Barney, Milo A and Neil C. Frischknecht. 1974. Vegetation Changes Following Fire in the 

Pinyon-Juniper Type of West-Central Utah. Journal of Range Management. Vol 27, No 2. pp 

91-96 (March 1974). Available at http://www4.nau.edu/direnet/publications/publications_b/

files/barney_frischknecht_1974.pdf

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Battaglin et al. 2000 

Battaglin, W.A., E.T. Furlong, M.R. Burkhardt, and C.J. Peter. 2000. Occurrence of 

Sulfonylurea, Sulfonamide, Imidazolinone, and Other Herbicides in Rivers, Reservoirs and 

Ground Water in the Midwestern United States, 1998. Science of the Total Environment 

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Battaglin et al. 2003

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Final Environmental Impact Statement: List of Preparers

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List of Preparers

Cathi Bailey – Outdoor Recreation Planner and Program Lead for Recreation, Visual Resources, and Wild and 

Scenic Rivers. Cathi has a B.S. in Wildland Recreation Management from the University of Idaho. She has 

worked for federal land and water management agencies for 22 years in California, Wyoming, and Oregon. Cathi 

has held positions as an Outdoor Recreation Planner, Natural Resource Specialist, Interdisciplinary Program 

Coordinator, and Environmental Specialist. 

Richard Bailey – Archeologist/Cultural Heritage Program Manager. Richard received a B.S. in Sociology/Anthropology from Montana State University and a M.A. in Anthropology from Washington State University. He has 

worked for archaeological contracting firms and universities including the Washington Archaeological Research 

Center at Washington State University. He has worked with the Spokane District BLM since 1993 and is currently 

the District Archaeologist. His professional research interests include ethno-botany, lithics, and historic preservation. 

Michael Crawford – Seed Orchard Program Manager. Mike has a B.S. in Forest Science from The 

Pennsylvania State University. Mike has worked for the BLM orchard program for 11 years. He also spent 8 

years working as a forester/silviculturist for the U.S. Forest Service and 6 years as a forester/research assistant for 

Oregon State University. Mike has been involved with work in orchard management, operational reforestation/

regeneration, and reforestation research. 

Christi Denton - Database Coordinator – Writer/Editor. Christi graduated from Mills College with a B.A. in 

2000, and got a graduate degree from CCMIX in France in 2004. She worked as a database engineer for several 

software companies in the San Francisco Bay Area, and then as an administrator and logistician for NGOs and 

other non-profits. She was the writer/editor - database coordinator on the Survey and Manage SEIS Team (2007). 

She is currently the owner of an environmental company that prepares NEPA documents.

Ken Denton – Team Leader. Ken has a B.S. in Natural Resources from Humboldt State. He was with the Forest 

Service for 34 years until 2004, working in silviculture and planning in California, Idaho, and Oregon. He served 

most recently on the interdisciplinary teams for the Forest Service EIS for the northern spotted owl (1992), 

the Northwest Forest Plan SEIS (1994), the Survey and Manage SEISs (2000, 2004), and was Team Leader 

for the Port-Orford-cedar SEIS (2004) and Survey and Manage SEIS (2007). He is currently a partner in an 

environmental company that prepares NEPA documents.

Al Doelker - Fisheries Biologist. Al received a B.S. in Fisheries Biology from Humboldt State University. After 

seasonal employment with the BLM, U.S. Forest Service, and Army Corps of Engineers, he worked for a private 

salmon hatchery in Oregon. He has worked for the BLM since 1990, working in Arizona and Oregon. He has 

most recently been involved with broad scale aquatic and riparian monitoring and analysis, application of aquatic 

conservation strategies, database development, Endangered Species Act consultation, and compliance with the 

Clean Water Act.

Henry Eichman – Economist. Henry received a B.A. in Biology from Colorado College and a M.S. in 

Agricultural and Resource Economics from Oregon State University. He held positions as a biological technician 

for the Colorado Department of Wildlife, the US Forest Service Rocky Mountain Research Station, and the 

Rio Grande National Forest, and in 2006 began providing the BLM with social and economic support for site 

specific and programmatic planning efforts in Montana, New Mexico, Oregon, North Dakota, and South Dakota. 

Henry works for the Forest Service and provides social and economic support for Forest Service planning efforts 

throughout the nation. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Louisa Evers – Fire Ecologist. Louisa received a B.S. in Forestry from the University of Tennessee and an M.S. 

in Forest Resources Management from the University of Idaho. Louisa has 28 years of experience in wildland 

fire and 20 years as a fuels specialist and fire ecologist in the Northern Rockies, Pacific Northwest, Great Basin, 

and Southwest for both the Forest Service and BLM. She currently has responsibilities in fire ecology, NEPA, 

monitoring, fire behavior, managing wildfires for resource benefits, and climate change.

Karl Ford – Toxicologist. Karl has a Ph.D in Environmental Health from Colorado State University. He 

worked for several national environmental consulting firms in toxicology and hazardous waste and served on 

the faculty at California State University Northridge. For the past 17 years, he has served as BLM’s toxicologist 

and remediation advisor throughout the 12 western states, including serving as an advisor in toxicology and risk 

assessment for the PEIS 2003-2007, and instructing Certified Pest Management class.

Maya Fuller – Public Affairs Specialist. Maya has a B.A. from the University of Oregon and a Masters of 

Public Administration from Portland State University. Maya develops and coordinates public outreach efforts 

and manages high profile issues for the BLM. Her primary functions are problem solving and issue resolution, 

information sharing, reporting, and media relations. 

Paul Fyfield – Cartographer. Paul received his Masters degree in Geography from Portland State University 

in 2003. He has worked at the Bureau of Land Management Oregon State Office in Portland since 2001. His 

cartographic work has included mapping in support of many BLM planning documents, mapping wilderness 

proposals at congressional request on both BLM and Forest Service land, and the multi-agency Pacific Northwest 

Recreation Map Series covering Oregon and Washington states.

Ellen Michaels Goheen - Plant Pathologist. Ellen received her B.S. in Forestry from the University of Montana 

and M.S. in Plant Pathology from Washington State University. She has worked on the Forest Health Protection 

staff of the Forest Service since 1983. She is the lead plant pathologist for the Pacific Northwest Region’s Sudden 

Oak Death program. 

Gary R. Harris - Tribal Relations. Gary graduated from Southern Illinois University with a B.S. in Forestry in 

1979, and received a Certificate from the U.S. Department of Defense Information Officer School at Ft. Mead, 

Maryland. He has worked for the Forest Service on four national forests and two regional offices as a forestry 

technician, forester, forest plan writer-editor, GIS coordinator, ranger district management assistant, district ranger, 

and regional legislative affairs program manager. He is currently the Tribal Relations Staff for both the USDA Forest 

Service R6 Regional Forester and USDI Bureau of Land Management Oregon/Washington State Director.

Robert G. Hopper - Rangeland Management Specialist and Wild Horses and Burro Program Lead. Robert 

obtained a B.S. in Range Management from Washington State University. He has served in his current position in 

the Oregon State Office since January 2007. He has held positions with the BLM in Nevada and Oregon as a soil 

scientist, range management specialist, supervisory rangeland management specialist and a supervisory natural 

resource specialist. He tasks include fire restoration, prescribed fire planning and implementation, grazing permit 

renewals and administration, and wild horse and burro management.

Carole Jorgensen – Wildlife Biologist. Carole received a B.S. from the University of Montana. She worked for 

three years with the US Fish and Wildlife Service before working for the BLM in Eugene, Rawlins, Prineville, 

Lakeview, a detail in the Washington DC office, and now as District Wildlife Biologist in Medford BLM. She is a 

member of several professional societies. Her primary professional interests include ecological relationships, rare 

species management, carnivore biology—particularly bears, and public land management.
Final Environmental Impact Statement: List of Preparers

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Brenda Lincoln Wojtanik – Program Analyst. Brenda received a B.A. in Political Science from the State University of New York at Albany and an M.S. in Environmental Science from the State University of New York, 

College of Environmental Science and Forestry. Brenda has worked as a public affairs specialist with the BLM 

Oregon State Office and as the Deputy Communications Team Leader for the Interior Columbia Basin Ecosystem 

Management Project. She currently provides project support to the Vegetation Treatments Using Herbicides on 

BLM Lands in Oregon EIS team.

Jerry Magee –Wilderness and National Landscape Conservation System Program Lead. Jerry has a B.S. in 

Environmental Planning & Management from the University of California, Davis, and a Master of Environmental 

Law and Policy from Vermont Law School. He has worked for the BLM since 1976 beginning as Outdoor Recreation Planner and Wilderness Specialist, and since severing on various EIS teams and in NEPA and environmental 

planning jobs at district or state offices in California and Oregon, with details to the Washington D.C. Office and 

to the Department of the Interior. He is currently the Wilderness and National Landscape Conservation System 

Program Lead in the BLM state office in Oregon. 

Leanne Mruzik - Fuels Management Specialist. Leanne completed the Technical Fire Management (TFM) 

program accredited through Colorado State University in 2000. Leanne began her career in fire in 1987, and 

continued working seasonally with the Forest Service on the Klamath and Shasta-Trinity National Forest in 

California until 1996. In 1997, Leanne joined the BLM on the Medford District as a fuels management specialist 

and eventually becoming the fuels program lead for the Butte Falls Resource Area, until being hired into her 

position at the State Office as the Fuels Management Program Lead for Oregon and Washington in 2008. Leanne 

has been involved with watershed analysis, environmental analysis, planning and implementation of a complex 

integrated fuels management program, restoration projects, and community education and outreach projects 

related to fire and fuels. 

Adrienne Pilmanis - Botanist. Adrienne has a BS in Biology from the University of Colorado, an MS in Botany 

from Duke University. She started working in ecology and botany in the early 1990's doing seasonal ecological 

studies on the Nevada Test Site. She spent several years doing advanced academic research before joining the 

Oregon State office of BLM as the Regional Data Steward for the Special Status Species Program in 2005, and 

is now the Botany Lead at the BLM Wyoming State Office. Adrienne's research included spatial analysis of soil 

and vegetation heterogeneity in disturbed Chihuahuan desert, nitrogen cycling under simulated global change 

scenarios in Colorado Plateau grasslands, and Holocene vegetation and fire history in northwestern Ontario. . 

Jeff Rose - BLM Eastern Oregon Sagebrush Conservation Coordinator. Jeff has a MS in Rangeland Resources 

from Oregon State University. Beginning in 1986, he has served as a Range Conservationist for the Confederated 

Tribes of Warm Springs, Research Associated for the Eastern Oregon Agricultural Research Center in Burns, 

OR, and as a Fire Ecologist for the Burns District of the Bureau of Land Management. Jeff has authored or 

coauthored 15 journal articles relating to ecology and management of western juniper woodlands and sagebrush 

steppe habitats. In his current position, Jeff works with BLM districts in Oregon to coordinate restoration and 

conservation activities concentrating on sagebrush and western juniper habitats.

Jeanne M. Standley – Botanist and Weed Coordinator. Jeanne has a B.S in Rangeland Resources at Oregon 

State University. She began her federal career with the Soil Conservation Service in eastern Oregon in 1983. 

She worked seasonally for the Extension Service in Roseburg as a Forestry technician and as a botanist for the 

USFS in Glide, OR, and joined the BLM in 1986. Jeanne served as the district weed coordinator and botanist in 

Roseburg, and as the state program lead for several programs in Alaska including Forestry, Botany, Range, and 

Weeds, as well as co-leading a team to implement Burned Area Emergency Stabilization and Rehabilitation on 6.4 

million acres. She is the weed coordinator with the Coos Bay District, and a member of the EIS core team. 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Dale A. Stewart – Soil Scientist. Dale obtained a B.S in Forestry and a M.S. in Biological Sciences from 

Michigan Technological University. He worked for the United States Forest Service on the Fremont National 

Forest in Oregon and the Ouachita National Forest in western Arkansas. He has worked for the BLM, Coos 

Bay District since 1986 in forest management as a timber sale administrator and planner, silviculturist, and since 

1994, as the district soil scientist. He has been involved in watershed analysis, environmental analysis, and 

implementation of forest management activities and restoration projects such as road decommissioning, culvert 

replacements and sediment control

Eric Stone - Program Analyst, Planning and NEPA. Eric obtained a B.S. in Forestry from the University of 

Connecticut and a M.S. in Forest Management from Oregon State University. He is currently employed as a 

consultant with the Oregon State Office, BLM in Portland Oregon. Before retiring from the BLM, he had held 

positions as a field forester, natural resource specialist, environmental coordinator, regional planner and program 

analyst from 1969-2004. He was involved at the State Office level in all land use planning and major activity 

plans in Oregon/Washington from 1980-2004. He has previously worked in the BLM Salem District and Eastern 

States and Montana State Offices.

Todd Thompson – Natural Resource Specialist – Restoration Coordinator and Vegetation Treatments EIS Team 

Project Manager. Todd has a B.S. in Wildlife Resources from the University of Idaho in Moscow. He worked 

for the Idaho Fish & Game as a Wildlife Technician before joining the BLM in Spokane where he was the 

Border Resource Area Wildlife Biologist and in 1996 became District Fish, Wildlife & Botany Program lead. 

Before managing the EIS Team, he was primarily involved in partner-based habitat restoration and vegetation 

management projects including a number of shrub-steppe and riparian/aquatic projects located throughout eastern 

Washington and northern Idaho. 

Carol Thornton – Hydrologist. Carol has a B.S. in Geology from the University of Oregon and a M.S. in 

Hydrology from the University of Nevada Reno. She worked for BLM for two years as a hydrologist and then 

went to work in 2002 for the Forest Service as a member of TEAMS, an enterprise unit. Her work takes her to 

projects throughout the west and occasionally to the eastern U.S. NEPA projects include timber sales, salvage 

sales, and other invasive plant EIS's. Non-NEPA projects have included stream surveys and watershed analysis.

Brian J. Watts - Fire Ecologist. Brian has a B.S. in Rangeland Management from Oregon State University. 

Brian has worked in both Range Management and Fire Management since 1992 with both the United States 

Forest Service and BLM in Oregon, Idaho, Nevada, and New Mexico. He is currently Fire Ecologist with the 

Bureau of Land Management on the Vale District in eastern Oregon. 

Public Comment Analysis Team

Carolyn Sharp – Public Comment Coding Lead. Carolyn has a Masters degree in Urban and Regional Planning 

from Portland State University and a Bachelors of Science in Environmental Studies from Florida International 

University. She is the owner of Sharp Communication, LLC, specializing in public involvement, environmental 

planning, and technical writing. With ten years of experience in environmental planning for local governments, 

she has four years of experience implementing public outreach strategies and two years of experience analyzing 

public comments for a large capital infrastructure project undergoing NEPA analysis.

The public comment coding team included BLM botanists Claire Hibler, Robin Taylor-Davenport, and 

Marcia Wineteer; Denton and Denton Environmental planners Markus Mead and Tiffany Gray and wildlife 

biologist Carroll Albert; and Mason, Bruce and Girard planners Jonathon Belmont, Kate Parker, and Brian 

Cook and technical writer Daniel Trudo.
Final Environmental Impact Statement: List of Preparers

425

Special Acknowledgments

Jerry Asher - Retired BLM special assistant to the State Director for noxious and other invasive weeds. Thanks 

for the references, leads, review of working papers, and review of the EIS.

Program and other specialists in the BLM Oregon State Office for contributing technical information to a 

section, or contributing to other aspects of the document preparation: Margaret Langlas (planning), Craig 

Ducey (GIS); Michael Campbell (public affairs); Jeannette Griese (timber); John Styduhar (rights-of-way); 

Ron Tuttle and Don Ehrich (administrative sites); Chris Knauf (OHVs); Janell Addison and Elaine Marie 

Macon (administrative support); Joan Seevers (Research Natural Areas); Steve Bulkin (Human Health), Shelly 

York and David Garcia (Document preparation and printing).

BLM District Weed Coordinators: Dan Tippy, Lynn Silva, Mike Woods, Lesley Richman, Erin McConnell, 

Molly Boyter, Claire Hibler, Nancy Sawtelle, Susan Carter, Mark Mousseaux, Glen Harkleroad, Brennan Hauk, 

Jennifer Moffit, Jeff Moss, Caryn Meinicke, and Jeanne Standley

Steering Committee:

Mike Mottice (Deputy State Director to May 2009), Mike Haske (Deputy State Director since May 2009), Miles 

Brown (Branch Chief, Rangeland Resource, Recreation, and Wilderness), Dave Henderson (District Manager, 

Vale to December 2009), Don Gonzales (District Manager, Vale since December 2009), Mark Johnson, EIS 

Steering Committee President (District Manager, Coos Bay)

About 30 internal reviewers and the members of the Southeast Oregon Resource Advisory Council and the John 

Day/Snake Resource Advisory Council for their pre-publication review. 

Rochelle Desser, Doug Daoust, Shawna Bautista, Cathy Selby, and other members of the Forest Service Invasive 

Plant EIS Team.

Susan Hale and the members of the public who participated in scoping in July 2008.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Final Environmental Impact Statement: Distribution List

427

Distribution List

In June of 2008, the Oregon BLM sent out 17,200 postcards and 2,000 emails notifying individuals and organizations 

that the Oregon BLM was going to begin preparation of this EIS. The postcards and emails advised how to get on the 

mailing list and when scoping meetings would be held. Those notified included: State and Federal elected officials; 

American Indian Tribes and Nations; lessees of BLM land; Soil and Water Conservation Districts and Oregon State 

University Extension Boards, as well as other interested parties identified by the Oregon Department of Agriculture; 

and, mailing lists from other planning efforts including the Western Oregon Plan Revisions, the Forest Service’s 

Invasive Plant EIS, the National PEIS, and all Oregon BLM districts’ mailing lists of persons having expressed an 

interest in being kept informed about local BLM planning efforts.

At the same time, approximately 400 press releases were sent to media outlets throughout the State. Newspapers do not 

have to publish news releases, but articles were published in several papers, including the Oregonian and the Ontario 

Argus Observer, and the issue received airtime on KEX and KCBY.

In addition, a Notice of Intent was published in the Federal Register on June 23, 2008. The Federal Register notice, 

news releases, and the postcards all announced the twelve scoping meetings, subsequently held throughout the State in 

July 2008.

About 1,300 interested parties were on the mailing list to receive the Draft EIS and about 2,000 interested parties are on 

the mailing list (below) to receive the Final EIS. Per NEPA regulations (40 C.F.R 1502.10), the Draft and the Final EIS 

includes the names and/or organizations of all parties who are on the mailing lists. 

Elected Officials

Governor Ted Kulongoski

U.S Senators

Ron Wyden

Jeff Merkley

U.S. Representatives

David Wu

Greg Walden

Earl Blumenauer

Peter DeFazio

Kurt Schrader

Oregon State Senators

Jason Atkinson

Alan Bates

Suzanne Bonamici

Brian Boquist

Ginny Burdick

Margaret Carter

Peter Courtney

Richard Devlin

Jackie Dingfelder

Ted Ferrioli

Larry George

Fred Girod

Mark Hass

Ken Jacobsen

Betsy Johnson

Jeff Kruse

Rick Metsger

Laurie Monnes Anderson

Rod Monroe

Bill Morrisette

Frank Morse

David Nelson

Floyd Prozanski

Diane Rosenbaum

Bruce Starr

Chris Telfer

Joanne Verger

Joanne Verger

Vicki Walker

Doug Whitsett

Jackie Winters
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 428

Oregon State Representatives

Jules Bailey

Jeff Barker

Phil Barnhart

Brent Barton

Cliff Bentz

Vicki Berger

Elizabeth Beyer

Deborah Boone

Scott Bruun

Peter Buckley

Kevin Cameron

Ben Cannon

Brian Clem

Jean Cowan

Michael Dembrow

Chris Edwards

David Edwards

Sal Esquivel

Tim Freeman

Larry Galizio

Bill Garrard

Chris Garrett

Sara Gelser

Vic Gilliam

George Gilman

Mitch Greenlick

Bruce Hanna

Chris Harker

Paul Holvey

John Huffman

Dave Hunt

Bob Jenson

Nick Kahl

Bill Kennemer

Betty Komp

Tina Kotek

Wayne Krieger

Greg Matthews

Ron Maurer

Nancy Nathanson

Mary Nolan

Andy Olson

Tobias Read

Dennis Richardson

Chuck Riley

Arnie Roblan

Mike Schaufler

Chip Shields

Greg Smith

Jefferson Smith

Sherrie Sprenger

Judy Stiegler

Kim Thatcher

Jim Thompson

Carolyn Tomei

Suzanne VanOrman

Jim Weidner

Gene Whisnant

Matt Wingard

Brad Witt

Washington State Senators

Ken Jacobsen

County Commissioners

Lane County Commissioner Faye Stewart

Lincoln County Commissioners

Stevens County Commissioners

Tillamook County Commissioner Charles Hurliman
Final Environmental Impact Statement: Distribution List

429

Federal Agencies

Environmental Protection Agency

Region 10

Department of Agriculture

Forest Service

Region 6

Bend/Fort Rock Ranger District

Modoc National Forest

Ochoco National Forest

Wallowa-Whitman National Forest

Winema National Forest 

PNW Research Station

Natural Resource Conservation Service

Department of Commerce

NOAA Fisheries

Department of Defense

US Army Corps of Engineers

Department of Energy

Bonneville Power Administration

Department of the Interior

Bureau of Indian Affairs

Bureau of Land Management

Washington D.C. (National) Office

California State Office

Colorado State Office

Idaho State Office

Montana State Office

Nevada State Office

Oregon State Office

Arcata Office

Baker Office

Burns Office

Coos Bay Office

Eugene Office

Grants Pass Office

Klamath Falls Resource Area

Lakeview Office

Medford Office

Prineville Office

Roseburg Office

Salem Office

Tillamook Office

Vale Office

Spokane (WA) Office

Wenatchee (WA) Office

Lake Havasu (AZ) Office

Snake Resource Advisory Committee

Southeast Oregon Resource Advisory Committee

Bureau of Reclamation

Fish and Wildlife Service

Alaska Regional Office

Bend Field Office

Ecological Services Program

Eagle Creek National Fish Hatchery

Klamath Basin National Wildlife Refuge

National Park Service

Whitman Mission National Historic Site

USGS Research

Department of Justice

Bureau of Alcohol, Tobacco, Firearms and Explosives
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 430

State, County, and Local Governments

Idaho

Department of Lands

Oregon

Department of Agriculture

 Noxious Weed Control

Department of Environmental Quality

Department of Fish and Wildlife

Department of Forestry

Department of State Lands

Research Reserve South Slough NERR

Department of Transportation

District 11E

Parks and Recreation Department

Water Resources Department

Watershed Councils

Columbia Slough Watershed Council

Gilliam-East John Day Watershed Council

Harney County Watershed Council

Lower Columbia River Watershed Council

Malheur Watershed Council

McKenzie River Watershed Council

Mid John Day & Bridge Creek Watershed Councils

Mohawk Watershed Partnership

North Fork John Day Watershed Council 

Owyhee Watershed Council

Tualatin River Watershed Council 

Counties

Association of O & C Counties

Baker County Weed Control

Benton County

Coos County

Curry County

Deschutes County

 Sheriff’s Posse

Douglas County Land Dept

Garfield County Noxious Weed Control Board

Gilliam County Road Department

Harney County 

Court

Weed Board

Hood River County

Jackson County Roads and Parks

Josephine County Parks

Klamath County 

Weed Supervisor

Planning Department

Lane County 

Public Works

Council of Governments

Lincoln County Road Dept.

Linn County Road Department

Malheur County Weed Control

Marion County Public Works

Polk County Public Works

Sherman County Assessor

Umatilla County

Wallowa County

Wasco County Weed Department

Yamhill County Sheriff Crabtree

Cities

Canyon City Watermaster Office

Cottage Grove

Hillsboro – Water Department

Medford Water Commission

Oxbow Park

Redmond

Salem Water Resources Section: Public Works Department

Washington

City Of Ilwaco

Washington Department of Fish and Wildlife

Webster Forest Nursery

WSDOT Southwestern Region

County Weed Boards

Klickitat County Noxious Weed Control Board

Lewis County Noxious Weed Control Board

Pend Oreille County Weed Board

Snohomish County Noxious Weed Control Board

Yakima County Noxious Weed Board
Final Environmental Impact Statement: Distribution List

431

American Indian Tribes and Nations

Burns Paiute Tribe

Confederated Tribes of Siletz Indians

Confederated Tribes of the Colville Reservation

Confederated Tribes of the Coos, Lower Umpqua and Siuslaw Indians

Confederated Tribes of the Grand Ronde Community of Oregon

Confederated Tribes of the Umatilla Indian Reservation

Coquille Tribe

Cow Creek Band of Umpqua Tribes of Indians

Fort Bidwell Indian Community

Fort McDermitt Tribe

Klamath Tribes

Latgawa Native American Indian Tribe

Nez Perce Tribe

Siletz Tribe

Warm Springs Reservation

Yakama Tribe

Businesses

ABC Tree Farms

Arrowhead Timber Company

Babylon Computer

Barnes Cattle Company

BASF Corporation

Benton Rock Products

Big Wind Oregon LLC

Boise Cascade Co

Box R Water Analysis Lab

Buckhorn Ranch

C&D Lumber Company

Capital Press

Central Lincoln People’s Utility District

Chevron Pipe Line Co

Coast Range Conifers LLC

Comfort Control Heating

Consumers Power Inc.

Coos County Sheep Company

Corbett Water District

Crook Timberlands LLC

Crump Ranch

Curtis Wicks Contracting

Custom Installation

Devil’s Canyon Ranch

Douglas Electric Coop

Douglas Timber Operators

Dow AgroSciences

DuPont Crop Protection

Ed Garrett Ranch, Inc

Emigrant Creek Ranch

E.I. DuPont de Nemours and Company

ENSR International

EP Minerals LLC

ERA All State Real Estate

Eugene Water & Electric Board 

Ferris Creek Ranch

Ferris Nursery

Flying Buffalo Ranches

Forest Capital Partners

Freres Timber Inc

Georgia Pacific LP

Giustina Land & Timber Co

Giustina Resources

Greyskull Enterprise, LLC

Habitat Creations

Haglund Kelley

Hammond Ranches, Inc

Healy Ranch

HGJ Livestock

High Desert Museum

High Heaven Timberlands

Hollingsworth Tree Farms LLC

Idaho Power

Indian Hill, LLC

Inform Media

Inshallah Ranch Inc.

Jacobs Ranch
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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James Matteri & Sons

Jerry & Linda Miller Ranch LLC

JKs Rough String Ranch

JWTR LLC

Lane Electric Coop

Loghouse Plants

Lone Rock Timber Management Company

Mackenzie Ranch

M.A. Palmer & Sons Inc

McMinnville Water and Light

MBM Group

McDade Ranch

Miller Ranch

Morgan Woods

Mortimore Corporation

North Unit Irrigation District

Ochoco Valley Ranch

Optasite Towers LLC

Oregon - Idaho Utilities

Oregon End Ranch

Oregon Safe Tree, Inc.

Overland Ranch

Owyhee Grazing Association, LLC

Pacific Analytics

Panhandle Spray Service

Pesticide Research Institute

PFC Properties

Plum Creek Timber Company

Port of Coquille River

Portland General Electric

Pryor Land And Livestock Inc.

Rashford Tree Farm

Raven Research

Resource Management Services

River Run Ranch

Rosboro, LLC

Roseburg Forest Products

Roseburg Resources Company

Roxy Ann Gem and Mineral / Crater Rock Museum

Sainte Partners II, L.P.

Scientific Ecological Services

Seneca Jones Timber Co

Seneca Sawmill Company

Silvies Valley Ranch LLC

Sno-Peak Nobles

Spirit Lake Industrial Park

Starfire Lumber Company

Stimson Lumber Company

Stuntzner Engineering

The Final Edition / Mt. Family Calendar

Timber Products Company

Tree Top Ranches

Tri-Creek Ranch

TtEC

Up the Creek Ranch

URS Corporation

Westfall Ranches

Weyerhaeuser Company

Whitewater Ranch

Wild and Scenic Nursery

William Smith Properties

Willow-Witt Ranch

YJ Ranch
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Other Organizations

Cooperative Weed Management Areas

Diamond Valley CWMA

Harney County CWMA

Lake County CWMA

Tri-County CWMA

Jordan Valley CWMA

Soil and Water Conservation Districts

Crook County SWCD

Douglas SWCD

East Multnomah SWCD

Josephine County SWCD

Marion SWCD

Polk SWCD

Sherman County SWCD

Tualatin SWCD

Upper Willamette SWCD

West Multnomah SWCD

American Forest Resource Council

Applegate Fire Plan

Applegate Forestry

Archaeological Society of Central Oregon (ASCO)

Associated Oregon Loggers

Audubon Society of Portland

Back Country Horsemen and Oregon Equestrian Trails

Bark

Blue Mountains Biodiversity Project and League of 

Wilderness Defenders

Blue Ribbon Coalition

Camp Forest

Canaries Who Sing, Gaia Vision, Coast Range Guardians, 

Residents of Oregon Against Deadly Spray and Smoke, 

and Citizens Environmental Protection Alliance

Cape Arago Audubon Socienty

Cascade Geographic Society

Cascadia Wildlands Project

Cascadia’s Ecosystem Advocates

Center for Biological Diversity

Central Oregon Shooting Sports Association

Citizens for Florence

Citizens Environmental Protection Alliance

Citizens Interested In Bull Run

Coast Range Guardians

Concerned Citizens for Clean Air

Corkscrew Trail

Crescent Water Association

Deer Creek Valley Natural Resources Conservation 

Association

Defenders of Wildlife

Deschutes Land Trust

Ecola Creek Awareness Project

Emerald Chapter, Oregon Society of American Foresters

Environment and Human Rights Advisory

Fir Point Bible Conference

Forestland Dwellers

Forestry Action Committee

Greater Greenwater Gateway Committee

Hells Canyon Preservation Council

Hugo Neighborhood Assoc. & Historical Society 

Human Downstream

Institute for Applied Ecology

Institute for Culture and Ecology

International Society for the Protection of Mustangs and 

Burros

Izaak Walton League of America

John Day Basin Trust

Josephine County OSU Extension Office

Kalmiopsis Audubon Society

Kettle Range Conservation Group

Klamath Forest Alliance

Klamath Siskiyou Wildlands Center

Kootenai Environmental Alliance

Lacomb Irrigation District

Lane County Audubon Society

Legacy Lands Project

Lick Creek Road Association

Lincoln County Mycological Society

Lyons Gulch P O A

Mohawk Valley Community Grange

Motorcycle Riders Association

Mt Hood Corridor Community Planning Organization

North American Butterfly Association

Eugene/Springfield Chapter

Northcoast Environmental Center

Northwest Coalition for Alternatives to Pesticides

Northwest Environmental Advocates

Northwest Environmental Defense Center

Northwest Weed Management Partnership

OHA Harney County Chapter

Oregon Cattlemen’s Association

Oregon Center for Environmental Health

Oregon Council Trout Unlimited

Oregon Environmental Council

Oregon Farm Bureau Federation

Oregon Grotto

Oregon Hunters Association
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Oregon Natural Desert Association

Oregon Recreation Coalition

Oregon Society of American Foresters

Oregon State Snowmobile Association

Oregon Toxics Alliance

Oregon Wild

Oregonians for Food and Shelter

Pacific Biodiversity Institute

Pacific Northwest 4 Wheel Drive Association

Pacific Rivers Council

Parsnip Peak Grazing Association

Partnership for the Umpqua Rivers

Pitchfork Rebellion

Plas Newydd

Redmond Oregon Hunters Association

Rocky Mountain Elk Foundation

Rockydale Neighborhood Association

Rogue Snowmobilers

Rogue Group Sierra Club

Rogue Valley Audubon Society

Sagebrush Sea Campaign

Save Our Ecosystems

Selkirk Conservation Alliance

Sierra Club

Siskiyou Project

SOLV

Somerset Hills III HOA

Southeast Oregon Resource Advisory Council

Sunriver Owners Association

The Nature Conservancy

Threatened and Endangered Little Applegate Valley

TraditionalMountaineering.org

Tumalo Irrigation District

Umpqua Valley Audubon Society

Umpqua Watersheds, Inc.

Urban Forager

Wallowa Canyonlands Partnership

Western Watersheds Projects

Wilderness Watch

Wildlife Forever

Willamette Agate and Mineral Society

Willamette Valley Grotto

Williams Community Forest Project

Williams Waterways Project

WOPR & Beyond Coalition

Libraries, Schools, and Universities

Ashland Public Library

Colorado State University Libraries

Corvallis- Benton County Public Library

Dallas Public Library

Douglas County Library System

Eagle Point Public Library

Klamath County Library

Lake County Library

Lewis and Clark College 

Lewis and Clark Law School: Boley Law Library

University of Washington: Natural Sciences Library

Oregon State University

Agricultural Program

Columbia Basin Agricultural Research Center

Department of Crop & Soil Science

Extension Service - Pendleton

Forest Engineering Department

Klamath Basin Research and Extension Center

Library

Rangeland Ecology and Management

Northwestern University – Environmental Policy and 

Culture Program

Rogue Community College

Ruch Public Library

South Lane School District 4553

Southern Oregon University

Springfield Public Library

Thomas Creek Library

University of Georgia – Center for Invasive Species and 

Ecosystem Health

University of Minnesota: Forestry Library

University of Notre Dame

University of Oregon 

Library

School of Law

USDA National Agricultural Library
Final Environmental Impact Statement: Distribution List

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Media

Argus Observer (Ontario)

Eugene Weekly

KLCC Radio (Eugene)

News-Register (McMinnville)

Individuals

Diana Abernathey

Sandra Ackley

Chad S Adams

Mark Adams

Noel Adams

John and Judy Ahmann

Diane Albino

John Albisu

George and Frances Alderson

Ken and Jan Alexander

Mike Allen

Bill and Kathleen Allison

Scott Allison

B M Alphent

Laurie Altier

Diane Amarotico

Guenter Ambron

Craig Ambrose

Nancy Ames

Carol Ampel

Dale Anderson

Michele Anderson

Nancy and Bert Anderson

Sean Anderson

Steve Anderson

Terry and Candice Anderson

Judith Ano

S B Anpu

Kimberly Anstey

Charlotte Anthenisen

Karl G Anuta

Nickolas Anzelmo

Maggie Appel

John Applegarth

John S Applegarth

Rick Applegate

Dick Artley

Philip N Arvin

Jerry Asher

Stephen D Auerbach

Fred and Sandra Austin

James W Ayling

Roderick K Baca

Joshua Baeckel

T Baer

Darrel Bagley

Anna Baio

James Baird

Jack Baker

Kimberly Baker

Loraine Baker Hanley 

Lorna Baldwin

Lorna Baldwin

Edwin Ball

Karen Bankole

Steven Baratz

Sterl and Ux Bare

Miles Barger

Richard Barnes

Donald Barnhart

Anthony Barreiro

Daniel Barron

Joey Barrote

Shannon Bartow

Katy Bartzokis

Christine Barvin

Dan and Theresa Bastian

Susan Bastian

James Batdorff

Gail Battaglia

Aubrey Bauer

Kevin and Heidi Bauer

Ted J Bauer

Craig Bauman

Kenneth F Baumann

Bruce Bayles

Gus Beall

D.A. Beauchamp

Paula Beckley

Ruth Belcher

Mickey Bellman

Peter&Mary Belov

Jim Bender

Linda Bentz

Terry Bequette

Peter Bergin

Bob Berman

Sharee Berman

Roy Beyer

Emerson Biehl

Joanne Bigman

Cynthia Biles

Rex Billingsley

Nanette S Bingaman Schultz 

Geraldine Bish

Kathleen Bishop

Sue Bitterling

Keeley Bittner

K E Black

Foy T Blackburn

Richard Blackwell

Larry Blank

Wayne Blaylock

David Bohn

Derek Bolkard

Steve Bollock

Sam Booher

Fred Borngasser

Robert and Connie Boronda

Gert Borschowa

David A Bossuot

Rebecca Bosworth

Karen Sue Bower

Lynn Bowers

Alan Bowes

Duane Bowman

Marta Boyett

Melvin E Boyles

Brian A Bradley

N Bradley
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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P Bradley

Thomas A Branciforte

Christopher Bratt

Peter A Bray

Melissa Breed

Chris J and Lisa Brehmer 

Charles Brent

Mick Bress

Charles Bridges

Katharine Brigham

Jon and Jean Bright

Dianne Broderick

Alan Brooks

Jonathan Brooks

Jan Brotman

D Brown

Jack Brown

Jordan Brown

Marcia Brown

Vriean Brown

Thom Bruce

Lee Brumble

Cheryl Bruner

Paul and Christy Bryan

Arthur Buck

Kathy Buckles

Lora Buckley

Carl E and Elaine Budlong 

Frank Buell

Mimi Bulkley

John Bullock

Linda Bumpas

Glen Bundy

Sara Burant

Sam Burchell

Ken and Bernie Burkholder

Bruce M Burnett

Kandy Burns

Julia Burwell

Brian Busta

Julie Butche

Twila J Butler

Sandy Cabraser

Henry J Cadwell Jr 

Terry Cain

David Calahan

Bruce Campbell

B Cannady

Jim Cant

Jane Capizzi

Randolph S Carey Jr 

Carol Carlson

Craig Carlton - Cederglen 

Carol Carmick

Susan Carney

Jay B Carr

Joann Carrabbio

Michael Carrigan

Shawn Carroll

Annette Carson

Bobby Carter

Fay Carter

Avona L Carttier

Marvin and Edie Casey

Oshana Catranides

Donald Cavaletto

Carol Cesaletti

cvhxj cgjxgjx

Heather Chalmers

Jackson Champer

Miriam Champer

Lisa Champlin

Les Chapman

Mel Chase

David A Chasmar

Susan Chauncey

Richard G. Chenoweth

Renee Childs

Samantha Chirillo

Keith Chisholm

Merry J Christiansen

Christopher Christie

Denise Christine

Paul H Christman

Charles Churchill

Jane Civiletti

Tricia Clark-McDowell

James Clarkson

Kathryn Cleland Sipfle 

Barry Clock

Robert Clutter

Amber Cobourn

Robert Cochran

Marilyn Cohen

Grant Combs

Deborah Connolly

David Cook

John W Cook

Sheila Cook

D Cooke

Ed Cooley

Lori Cooper

Phillipe Coquet

Robert J Corbari

David Corby

Jennifer Corio

Michele Cornelius

Barbara K Cosby

Randy Cottrell

Arthur Coulton

Clayton M and Marilyn Couture 

Leslie Cox

Erika Coyer

Patrick Craig

Sandra and Stephen Cramer

Rebecca Crane

Jed Cravitts

Niko Cremer

Connie Crew

Phyllis Cribby

Sukita Crimmel

Laurel Croft

Dan and Laury Cron

Jerome Cronin

Monty Crum

Arleen Curths

Wanda Custance

Deborah Cuthane

Ruth Daemler

Laura A Dahl

J R Dallas

Ken Dalton

Michelle D’Amico

Jennifer Damon-Tollenaere

Oceanah D’amore

Ruth Danielsen

Stuart Davies

Charles Davis

Daniel Davis

Deniece Davis

Donald R Davis

Leontyne Davis

Martin Davis

Mike Davis

Robert B Davis

Ron and Mary Jo Davis

Bruce Dawley

D. Christopher Dawson

Fred A Dayton Jr 

Erik de Buhr 
Final Environmental Impact Statement: Distribution List

437

Dr Paul M Deauville 

Virginia and Don Debusk

Art Decker

Dee Decker

Joel Deese

Susanna DeFazio

Gary and Marjorie Defenbaugh

Michelle Deford

Ted E Deford

John DeGroot

Noah Deligia

Susan Delles

Sam Dement

Kenneth E Denton

Lisa M Derave

Diana Derwart

Lillian and Reggie DeSoto

Dorothy Detsch

Katie Dettman

Jill DeVine

Laura Devlin

Janene L Diaz

Juan Diaz

Ed Dierling

Karly Dillard

Krislyn Dillard

John B Dimick

Shauna Dingus

Melba Dlugonski

Kim Donahey

Diana Donaldson

Marc Donofrio

Mary P Dorroh

Sage and Lynne Dorsey

Melissa Dougherty

Myles Downes

Sean Downey

Patricia Downing

Sylvia Doxsee

Fred and Joy Doyle

Malcolm Drake

Randell Drake

Ray Drayton

Linda Driskill

Ruth Duemier

Jack Duggan

Agnes K Duncan

David J Duncan

Carol Dunten

John Duran

Nancy Duran

Joel Durr

Vern Eastburn

Keith Easterday

Francis Eatherington

Charles K Eckels Jr 

Jeanette Egger

Mark Egger

Burt and Linda Eikleberry

Cari Eisler

Robert Elder

Cerrissa Elleins

Rob Ellington

Lavon Elliott

Arthur Ellis

Maurice Ellsworth

John Elzey

Scott English

Stephen Eraker

Joseph Ereneta

Elizabeth Erfurth

Mel Ergekgoy

Lynne Erickson

Roddy Erickson

Chuck Erkenbeck

Joann Ernst

Mildred Eshelby

Angela Etter

Bill Evans

Jeanne Evans

Thea Evenstad

Herbert L Everett

Steve Everidge and Jeri Keatley 

Rodney Fagundes

Bruce Farmer

Joan Faulkner

John Felsner

James M Fenton

Draco Ferguson

Jo Ferneau

Robert A Ferreira

Jim Fety

Margot Fetz

Scott Fife

Antonette Figuendo

Deborah Filipelli

Dudley Finch

Jean Findley

Irachel Finolay

Richard Fleming

Bryan Flora

Mary Flowerday

Calvin Flowers

Susan Flynn

Ivan Forbes

Michael Fornalski

Greg and Rana Foster

Rana Foster

Stephen J Foster

Deborah Fox

Gail Frank

Winn Frankland

Sherry Franzen

Stephen Frazier

Denn Free

James Freeberg

Dr G.W. Freed-Rowland

Lincoln Freeman

Mark Freeman

Ross Freeman Levin 

P Freimuth

Paul Frey

Yvonne Fried

Dennis Fritzinger

Linda Frohbach

George Fuller

Doug Furlong

Rae Furrer

Richard G Furrer

John and Robin Gage

Dean Gaiser

Joyce P Gall

Scott Gall

John Galloway

Dr John L Gardiner 

Alexandra Gardner

Teresa Gardner

Valerie Garrick

Chris Garrison

Lydia Garvey

Pam Garvin

Cindy and Bruce Gates

John Geddie

Maya and Dan Gee

Jonathan Geoly

Eric Geyer

Ed Gibson

Randall Gicker

Wayne Giesy

James R Gilbert
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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William M Gilbert

Erna Gilbertson

Kent Gill

Alan Gillespie

Kathy Ging

Blair Girard

Suzi and Bob Given

Everlynn Gladiola

Thea Gladiola

T.R. Glasow

Janet Glassberg

Daniel Glenn

Richard Goble

Jim Goes

Elisabeth Goines

Esther Goldberg

Nabha Goldfeder

Janice Goldstein

Christine Golightly

Misha Gomez

Daniel Gonzalez

Amber Good

Ken Goodpaster

Cat Gould

Steve Grabs

Victoria Grace

Erin Grady

Michael Graham

Peter Graham

Will Grant

John Graves

Claudia Gray

Tim Greathouse

Ron Greb

Donna Green

Griffin Green

Scott Green

Cherry Gregory

Probyn Gregory

Ron L Gregory

Beth Grendahl

Jessica Gresmak

George Grier

Glen Griffith

Tom Gritzka

Al Grosz

G R Grovt

George R Gruning

Robert Gunther

Clifton Guyton

H. Elizabeth Gwynn and Lynda 

Blumenthal 

Kiley Gwynn

Amy Hack

Marion Hadden

Heidi Haehlen

Bob Hagerty

Clarence Hagmeier

Marlies Hahn

Giuliana Haim

Kyle Haines

Bill Hall

Chanah Hall

Michael Hall

Don Hamann

Liz Hampton

Al and Shawna Hanan

Christine Hanks

Jesse Hannon

Bruce Hansen

Anne Hanson

Nicole Hanson

Jeff Hanus

Susan Hardy Straub 

Amy Harlib

Barry Harper

Bert Harris

Eva Harris

Dennis Harrison

J Harrison

Josh Harrison

Keira Harrison

Paul Harrison

Terry Harrison

Steve Hart

Tyrell Hart

Cate Hartzell

Mark and Tammy Hastings

Robyn Hathcock

Scott Havill

John and Susan Hawksley

Maura Hayes

Richard Heaney

Carol Heart

Debbie Hebert

Morgan Heckman

Katherine J Heer

Dan H Heierman

Robert Hein

Martin Held

Delbert Heller

Roy Heller

Nathan Hendricks

Jerry Hendrickson

Paul Henion

Joe Henry

P Sydney Herbert

Kenny Herinck

MaryAnn Herral

Rand Herrick

Jacob Herringh

Carla Hervert

Azure Hess

Elizabeth A Hess

Jenni and David Hess

Martha Hess

Opie Heyerman

Dean Hibbs

John Hickam

Gregory Hickey

Maureen Hicks

Debra Higbee

Don Higby

Roxy Hiils

Frank Hill

Joel Hill

Gretchen Hillard

Juaglyn Hillman

Kay Hilton

John Hines

Duane Hinkley

JoAnn Hoeber

Arjen Hoekstra

Tom Hoesly

Loree Hoff

Michelle Hoff

David Hoffman

Rob Hoffman

Mike and Connie Hoffstetter

Jim Hogan

Peter Holden

Charles Holley

Elvera Holtz

Amanda Holzgang

Monica Honegger

Dennis Honkomp

Kenneth Hoppe

Karen Horn

Kathy Horn

David Horste
Final Environmental Impact Statement: Distribution List

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Harold Hotchkiss

Barbara Howard

Paul Howard

T Howell

Charles G Hoyle

Ann Hubbird

Ray Hudson

Arthur Huebner

Koema Hummingbird

Marcus Humus

Linda Hunt

Walter Hunt

Diana Huntington

Yvonne Hurst

Loretta Huston

Joseph Huth

George Ice

Chhaya Ichele

Yoshiko Ichinohe

Juliet P Imes

Jim Ince

Cheryl Ingersoll and Tyler Groo 

Charles E Ireland Jr 

Ruby Irish

Gina Isaac

Nancy Isham

Eric Jacobs

Esther Jacobson - Tepfer 

Peter James

William Jameson

Jason Jandl

Barbara Jansson

Carol Jaquet

Jocelyn Jenks

Courtlandt Jennings

Trip Jennings

Leonard Jennsen

Carol Jensen

Randye D Jensen

Shelley Jensen

Melanie Jessee

Sarah Jilka

Katia Jimenez

Douglas E Johnson

Kenneth Johnson

Paul S Johnson

Helen Jones

Scott Jones

Maureen Joplin

Rachel Jordan

Rob Joseph

Anthony Joyce

Owen Jurling

Cathy Justice

Tim Kaiser

Nikolaus Kamrath

Karyn Kaplan

Rob Karnuth

David Kaspar

Denny Kasunic

Teresa Kasza

Gail Katul

Gail S Katul

Kim Kauffman

Charles J Keegan

Michael Keerins

James C Keesey

Paul Keller

Barbara Kelley

Erica Kelley

Wayne Kelly

Alex Kendrick

Mark Kennedy

Eldon Kent

David Kerlick

Al Kernagis

Kammy Kern-Korot

Gail Kerns

Phyllis Kesner

Merle Kidwell

Siddiq Kilkenny

Martin Kilmer

Greg Kimball

Margaret Kimble

Reida Kimmel

Bob Kindschy

Eron King

Robert King

Samantha King

Jeff Kipilman

Kris Kirkeby

Lindea Kirschner

Kathy Kirsh

Monty Kizer

Basey Klopp

Rick L Klumph

Loren G Knight

Bill Kobialky

Victoria A Koch

Jeff Kochenderfer

Jon Koebel

John Koenig and Deborah 

Toobert 

Georgia Kollandra

Lucinda Kolo-Caron

Mike Konovalov

Brigitte Kranabitl

Keith D and Wendy K Kranz

Eric Kranzush

Perry L Krieger

Steve Kriegh

James and Catherine Krois

Mary Ann Kruse

Eugene Kunze and Christine 

Denton 

John Kunze

Amber Kurt

M. Dawn and Thomas Kurzka 

Janet La Fountain 

Gerard Labrecque

Robbin Lacy

Von Laine

Drew Laird

Jim and Rochelle Lake

Sylvia Lakey

Dennis Lambert

Jennifer Lance

Barbara Lane

David Lane

Jonathan I Lange

Steve Lanusse

Steve Lanusse-Siegel

Linda Lanzhammer

Claudia Lapp

Monty Larson

Pat Larson

Russell and Gail Larson

Terry Larson Sr.

Lu Laverde

David Lawrence

Fabian Lawrence

Sharon Lawrence

Len Lea

Darrell Leach

G L Leblanc

Christopher W Lee

Matthew Lee

Frank Leeds

Karen Lefer

Frank Lehram
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Hannah Leigh

Sharon Lemaster

John LeMasurier

Sheila Lemons

Jim Lemos

Johnathan Lenann

Spencer Lennard

George Lescher

Patricia and Maciej Lesiecki

Michael A Letendre

Sharon Levin

Kathy Levy

Dr Jonathan and Mrs Levy 

Bill Lewey

Abigail Lewis

Carlos Lewis

David C Lewis

Emma Leyburn

Daniel H Lichtenwald

Rozz Lieght

Fred Lifton

Chelsea Lincoln

Robert Lindsay

Lori Linehan

Alexander Lipshutz

Gary Lisman

Peter Little

Ronald and Claudia Little

Sara Livingston

Jason Lloyd

Olson Lloyd

Phil Loe

Caroline Loester

Geren and June Long

Herbert Long

Mary Lou LoPreste

Frank D Lospalluto

Toni Lovaglia

Nena Lovinger

Grant Low

Joseph T Low

Sheila Lowe

Pamela and Sherman Lucas

Jack Luce

Louise Luce

Cathy Lucero

Bill Luckey

Paul Luehrmann

Debbie Lukas

Sue Lynn

Sandra Lyon

Denise Lytle

James Maberry

Cathy Macay

Jeff Mach

Suzanna Mack

Wilson L Mackenzie

Kendra G Madden

Brian Maher

Dr Eugene I Majerowicz 

Ray and Beverly Major

Michael Mallo

Kathleen Maloney

Clifford Mann

Susan Manske

Ken Mantel

Sue Mapolski

Luna Marcus

Mark Mardon

Jason Margulis

D Maria

John and Bonnie Marineau

Albert Marra

Eve Marsh

Melissa Marsh

Donald Marshall

Travis Marshall

Sita Martin

Malena Marvin

D D Mascall

Charles and Christopher Mason

James Mast

Bill Mathison

Liz Matteson

Tara Mattis

Randy Matzek

Roger Maulding

Tom Maxwell

Darrell and Connie May

Joseph B Mazza

David McAllister

Tom McAllister

Kevin McBirney

Carol McBrian

Gregg McBride

Justin McBurnett

Amy McCall

Rebecca and Justus McCann

Josie McCarthy

Glenn McCaslin

John McClash

Roger McConnell

Bert L McCormack

C McCue

John McDonough

Bonnie McDroe

Debra E McGee

Wendy McGowan

Richard McGuinness

Dana McGuire

Mike and Victoria McKinney

Jennifer McKinnis

Richard McLead

Charles Otter McSweeney

Phil Meglasson

Susan Menanno

Sue Mendelson

Michael S Meredith

Edward M Merriman

Fred Mertzer

Warren Merz

Jason Messerle

Mario Messina

Gary Messinger

Bill Meyer

Diane Meyer

Lee Meyer

Cynthia Miani

William Michel

Eileen M Micke-Johnson

Dave Mickey

David Mildrexler

Jacqueline Milikien

Bonnie Miller

Chloe Miller

Dee Ann Miller

Gregory S Miller

Harriet Miller

Hubert Miller

Kenny C Miller

Pat and Naida Miller

Robert Miller

Ron Miller

Ronald W Miller

Russell L Miller

Sara Miller

William Miller

Anne Millhollen

Olympia Minard

James Minervini

Don Minore
Final Environmental Impact Statement: Distribution List

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Russ Minten

Ed Miranda Jr

Lisa Mischke

Albert Mitchell

Anne Mitchell

Bryce Mitchell

Chuck Mitchell

J Mitchell

Robbie Mitchell

Melissa Mitchell-Hooge

Frederick Mittleman

Mary Moffat

Clifton K Molatore

G L Monahan

Michael Monarch

William Mondale

David Monett

John Monroe

Edith Montgomery

Monty Montgomery

Julia Mooney

James F Moore

M L Moore

Vera and J Robert Moore

Mike and Betty Morgan

Raymond J Morris

Sharon Morris

C A Morrison and Pamela Schrimps 

Shelley Morrison

Chris Morstad

Peg Morton

Douglass Moser

Sayle Moser

Tobiah Moshier

Lola Moulton

Peter Moulton

Karen Mount

Kenneth B Mueller

Teresa Mueller

Dr Fraser J Muirhead 

Robert Mullong

Robert Mumby

Kurt R Munson

Daniel Murphy

James Murphy

Jean Murphy

R E Myer

Leo Naapi

Paula Naas

Lawrence Nagel

Gloria Nash

Richard Nauman

Rich Nawa

Paul E Neal

Wolfgang Nebmaier

Brent Neill

Hannah Nelson

Jan Nelson

Jean Nelson

Jeffrey Nelson

Leon C Neuschwander

Rick Nevitt-LaMantia

Judy Newton

Nancy Nichols

Chad Nicholson

Louise Nicholson

Scott Nilholson

Dave Noble

David Norem

Peter Norman

Jim Norris

Steven Novotny

David B Now

Charlotte Nuessle

Tom Nygren

Donald Oakes

Sally O’Donnell

Gregg Oelker

Laura M Ohanian

Conan Oharrow

Doug Oien

Erik Olaf

Jim Olney

Marti Olson

Regan Olson

Stuart O’Neill

Ludwig Opfermann

Susan Orluten

Barbara Orsow

Lynn Ortwein

Thomas and Terra O’Ryan

Larry Orzechowski

Fred Otley

David Owen

Michelle Owen

Cheryl Owens

Jim Oxyer

Stacy Page

Lawrence Pagen

Sarah Pagen

B Palmer

George L Palmer

Giancarlo Panagia

Saffo Papantonopoulou

Desiree Paqueth

Sandra Parnelle

Wallace N Parrish

Paul and Kathy Patrick

Craig Patterson

Derek Patterson

Frederick M Patton

Kathleen Patton

Kent D Patton

H D Patton Jr 

Ruth A Paul

Warren H Paulat

Grafton Pauls

E T Paulus

Wade R Peerman

Michele Penner

Barbara Pereina

George and Mary Perez

Laura Perrigan

Kialing Persy

Georgia Peters

Jim Petersen

Allan Peterson

Eric Peterson

Gary D Peterson

Leonard P and Ada Peterson 

Marilyn Pettenger

William Pettit

Glenda Phillips

Stuart Phillips

Bill Philp

David I Piccioni

Darrell R Pieper

Jonathan Pincus

Chuck Pinkerton

Priscilla Piper

John La Plante

Judith Platt

Tim Pledger

Chris Pollard

Tippi Pollet

Michael Port

Dick Posekany

Gary Powell

Philip T Powell

Nancy Powers
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Jim and Nancy Prince

Janet and Jeff Propp

Paula Ptacek

Jean Public

Jonah Pugh

Diana Purdy

Ron Quant

Keith Quick

Joseph Patrick Quinn

Paul D Quinn

Roger Rabb

Gary Rabideau

James Ragan

Roth and Cherri Randall

Taylor Randes

Dan Rasmussen

Philip Ratcliff

Cathy Raymer

Terry Raymer

Ina Marie Raymond

Russell Reade

Rusty Reaves

David Reed

Gary Reeser

Kathy Reid

Kari Rein

Christy and Ron Renchler

Ulrich Richard

Jay Richards

Bill Richardson

Jacob Richardson

Len Richardson

Matthew A Richardson

Phil Richman

Bark Richmond

Richard W and Joan Rickard 

Virginia Ricketts

Joe Rickner

Donna Riddle

Kenneth Rieck

Lyle Rilling

Laura R Rini

Melanie Rios

Denise Ripellino

Scott Ritner

Jennifer Rivais

Diane Rivas

Victor and Martha Robert

Harold Robertson

Cathy Robinson

Richard Robinson and Dorthy 

Robinson-Foldes 

Robert Rock

Jo Rodgers

Marcia Rodine

Marcia Rodine

Nancy Roeder

Marie Roehrich

Kim Roemer

Evelyn Roeth

Maggie Rogers

Ron Roggensack

Justin and Lisa Rohde

Ryan Rose

Marvin Rosenberg

David Rosenblatt

Sasha Rotecki

Naomi Rowden

Lynn Royce

Tim Rozewski

Aldine Rubinstein

Kevin Russell

Reed D Russell

Anton and Donna Rustand

Zola Ryan

B Sachau

Ron Sadler

John Saemann

Avery Safehaven

Gerald Sagert

Joseph Saine

Doug Saldivar

Heron Saline

DeAnne Salmon

Jo An Saltzen

Claire and Howard Sands

J K Sandt

Brian Santos

P Saraceno

Peter Saraceno

Don Sargent

Christina Sasser

John Sather

David Saul

Roger and Ellen Savage

Michelle Saxton

Kurt A and Kathryn Saylor 

Mike Schauther

Anthony Scherr

William Scheufele

Ken Schiff

Day Schildkret

Judith Schlacter

Earl Schlegel

Dean Schmidt

Kurt Schmidt

Tom Schmidt

Jennifer Schomp

Edward Schoor

David Schorran

Alan Schroeder

Steven Schultz

Carl H Schwarzenberg

Melissa Schweisguth

Cynthia Schwell

Larry Scofield

C Scott

Gordon Scott

Henry Scott

John and Delores Scott

Joel Sdeese

Kathy Seabrook

Darla Seagoe

Bonny Seal

Jim and Nancy Sears

Will Sears

Lloyd Seely

John Segundo

Carolyn Self

Lara Sernoffsky

Mohabee Serrano

Ezra Severine

Alex Sewell

Steve Sewell

Porter Sexton

Richard Shadoian

Bonnie Shaffer

Peggy Shaft

Jim Shake

Eric Shamay

Donna Sharp

Lynn Sharp

Jai Shayla

Kathleen M Shayler

Matthew Sheehan

Roger Sheley

Gabriel Sheridan

Terry Sherman

Dan Sherwood

Robert Shimane

Jack Shipley
Final Environmental Impact Statement: Distribution List

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Kirsten Shockey

Ron Short

Castro Shrader

J L Shultz

Richard Shuster

Richard G Shuster

Toni Siegrist

Adrienne Simmons

Terry Simpson and Jayne Goodwin 

Julia Siporin

Kevin Slager

Audrey Slater

Dudley Slater

Wayne Slawson

Charles Sliger

Garrett Slusky

Dennis R Smith

Jack G Smith

Jason Smith

Judy Smith

Larry Smith

Robert Smith

S K Smith

Susan Smith

Tony S Smith

Walter Smith

Paul Smoland

Max Smoot

Stuart Smythe

John Snelling

Harriet and Dennis Snyder

Sandra Soho

A Solak

Tanya Sommer

Josh Soran

Manual Soto

Don Southern

James Sowerwine

Linda Spangle

Jonathan Spero

David Spiciarich

Frank Spiecker

Vaughn Spiker

Richard Spotts

John Spragens

Robert Spragins

Bobby Stafford

John Stahl

Kathy Staley

Amanda Stanley, Ph.D 

Kathleen Stasny

Heather Stein

Steven Steinhauer

Paul Stell

Brandan Stemt

Ken Stern

Ted Stevens

Joanne and Kenneth Stevenson

Karen Stingle

Christine Stockdale

John L Stoddart

David Stone

Jeffrey Stone

JoAnne Stone

Paul Stone

Dianna Storli

Rick and Joann Stoughton

Kindler Stout

Joel Strab

Frank Stragar

Sherry Straus

Sally Streeter

Lotte Streisinger

Connie Stringer

Don Stroeber

Eric Stuit

Ed Styskel

Debra Sullivan

Renae Summershee

Micheal Sunanda

John Sundquist

Sue Supriano

Pete Swensen

Al Swisher

J T

Ross T

Deniz Tahinagly

Charles C Tandy

Buck and Linda Taylor

George and Rebecca Taylor

Laura Taylor

Joseph and Asa Tellschow

Judith A Templeton

Jason and Melene Terry

Thomas Thacker

Erich Thalmayer

Karen Theodure

Robert Thies

Patrice Thiessen

Harley D Thom

Charles Thomas

Lauri Thomas

Maggie and Jeff Thompson

Ambers Thornburgh

Marlene Thorp

Steven Tichenor

Gilbert J Ticoulat

Stephanie Tidwell

Hillary Tiefer

Ruth Tiger

Paul Tipton

Avery Gary Tittle

Debby Todd

Viggo Toftemark

William Toll

Billy and Dora Toman

Doris and Norm Tonseth

Ian Torrence

Paul Torrence

Hannah Torres

John R Townes

Lawrence and Gina Trafton

Trinity Treat

Jay Treiger

Gene Tresefeld

Rudy Trevino

Vicki Tripoli

James Turner

John Turner

Sheryl Tuttle

David Tvedt

Dee Tvedt

Joe Tyndall

Kathy Uhtoff

Larry Ulrich

Sarah Vaile

Carol Valentine

Gary Van Van Cleef

Jan Van Dusen

Charles Van Lear

Mark Van Ryzin 

Roberta Vandehey

Suzanne Vandeneynde

George VanderLinden

Floyd Vandervelden

Ian VanOrnum

Suzanne Vautier

Jenny Velinty

Cathy Verret

Fern L Vikerts
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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Ann Villarqui

Chuck Volz

Pete and Josephine von Hippel

Deborah Vukson

Lauria Wadsworth

David H Wagner

James Wagner

Lisa Wale

John and Janet Walker

Margaret Walker

Michael Walker

Thomas Walker

Wandalea Walker

James J Walters

Steven Walters

Aisha Wand

Roger Want

Anita and John Ward

Tom Ward

Peter and Diane Ware

Thomas Ware

Amy Warren

T D Warrick

Willard Wash

Stan Washburn

Linda Watts

Pam Watts

John Weatherman

Clint D Weaver

Ron Weaver

David Webb

Della Webb

R Weeks and G Griggs 

Sally Weersing

Katie Weidman

Heather Welburn

Joshua Welch

Greeley Wells

Jim Wells

Sharon Wendt

Clint and Cathy Wentz

Gerald West

Michael Wherley

Charles Whitaker

Frank G White

Jeffrey N White

Joshua White

Robert White

John Whitehead

Stephen Whitlock

Benjamin Whitney

Susan Whitney-Kurtz

H Wick

Gary Wickham

Mark Wienert Jr. 

Ken Wienke

Carol Wilcox

David Wilcoxen

David and Kathy Wilder

Glenna Wilder

Kay Wiley

George Wilkinson

James Wilkinson

Doreen Williams

Janese Williams

Ken Williams

Matt Williams

Mitch Williams

Robert J Williams

Bruce D and Christine Williams 

Mike Wills

Brian Wilson

Carol L Wilson

George C Wilson

Mouna Wilson

Mark and Robin Winfree-Andrew

Jason Winkel

David Winston

Edward Winter

Margery Winter

Shauna Wirth

Ryan Wishart

Jay and Mary Ann Wisman

Darryl Wisner

Jane and George Withers

Donald and Deborah Withrow

Matt Witt

Mervin Witt

Joanna Wnorowski-Pecoraro

Judy Wolfe

John and Polly Wood

Wendell Wood

Laurie Woodard

Elaine Woodriff

Jan Woods

Franklin L Woody Barnes JR 

Nancy Woolfson

Corry Wright

L K Wright

Rick Yaw and Diane Orrell 

Jeff Yockers

Kristi Yoder

Jack Young

Berta Youtie

Jackie Yow

Russ Yttri

Greg Zahradnik

Duane Zentner

Richard Zentzis

Carolyn Zetterberg

George Ziermann

Chris Zilka

Gloria Ziller

Marianne, Rae, and and Alan 

Zindal

Kenneth Zink

Marguery Lee Zucker
Final Environmental Impact Statement: Index

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Index

2,4-D .........................................xxix, 17, 18, 20, 30, 31, 37, 59, 62, 77, 80, 81, 83, 95-103, 116, 119, 145-146, 178, 181, 

182, 192-194, 199, 211, 214, 221, 222, 226, 229, 247, 262, 349, 353, 355, 356, 535, 607, 610, 617-623, 628

Accidental spill ....................................................................94-104, 116-117, 144, 201, 202, 211, 220, 222, 354, 810-811

Acronyms............................................................................................................................................................................ v

Adjuvant...................................................................................28, 58, 63, 64, 114, 194, 195, 228, 247, 353, 624-627, 820

Administrative sites ............................................................................................ 31, 77, 82, 83-85, 154, 311-318, 338-342

Aerial application.................................................29, 30, 34, 59-61, 65, 71, 79, 82, 95, 102, 104, 114, 144, 156, 199-200, 

208, 222, 254, 269, 318, 322, 353, 355

AgDrift.................................................................................................................................................................... 221, 347

ALS-inhibitor........................................................................................................................ 34, 62, 63, 145, 156, 228, 247

Application methods......................................................................................................................................70-73, 82, 254

Auxin transport inhibitor................................................................................................................................................. 147

Biological Control........................................................................................................... 66, 68, 76, 78, 139, 231, 253, 294

Brands.....................................................................................................................................................(see Formulations)

Bromacil.............................................xxix, 31, 59, 62, 77, 80, 94-104, 119, 146, 181, 182, 192, 193, 196, 199, 211, 212, 

224, 248, 261, 351, 355, 356, 535, 607, 609, 617-623, 630

Buffer distances................................................................................................................................................156, 466-467

Carotene inhibitor ........................................................................................................................................................... 147

Chlorsulfuron .......................... xxx, 30, 31, 34, 59, 63, 77, 80, 94-103, 119, 145, 181, 182, 196, 199, 211, 212, 222, 224, 

 248, 261, 349, 535, 607, 609, 617-623, 632

Clopyralid ............................................. xxx, 30, 31, 59, 63, 77, 80, 95-103, 119, 145, 178, 181, 182, 196, 199, 211, 213, 

226, 248, 262, 350, 535, 607, 609, 617-623, 633

Conservation Agreement............................................................................................................................................. 31, 32

Conservation Measures........................................ 29, 93, 142, 156, 486, 487, 490, 492, 506-510, 514, 516, 517, 533-539

Conservation Strategy............................................................................................................................... 31, 32, 77, 83, 85

Consultation ................................................................................................................................ 13, 22, 284, 292, 331, 485

Costs, or Implementation Costs......................................................................................................... (see Treatment Costs)

Cumulative impacts ............................ 117-120, 188, 207-208, 238-240, 257-258, 267, 273, 290-292, 327-328, 334, 342

Degradates................................................................................................................................................. 87, 114, 229, 818

Dicamba ..........................................xxix, 30, 31, 59, 63, 77, 80, 81, 95-103, 119, 145-146, 178, 181, 183, 193, 196, 199, 

211, 213, 226, 247, 263, 350, 355, 356, 536, 607, 611, 617-623, 634

Diflufenzopyr (+ dicamba)........................ xxx, 59, 63, 77, 80, 94-101, 119, 147, 181, 183, 196, 199, 211, 213, 224, 249, 

 261, 262, 348, 536, 537, 607, 611, 617-623, 635

Diquat................................................xxx, 59, 62, 77, 80, 94-101, 119, 146, 181, 183, 192, 194, 199, 214, 224, 236, 249, 

261, 348, 356, 536, 607, 612, 617-623, 636

Directed Livestock.......................................................................................................75, 78, 150, 231, 253, 293-294, 340

Diuron ..................................... xxx, 17, 20, 31, 60, 62, 77, 80, 94-104, 119, 146, 178, 181, 182, 193, 197, 199, 211, 213,

 224, 229, 249, 261, 352, 355, 356, 536, 607, 612, 617-623, 637
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Drift...........................................................................21, 88, 94-97, 144, 199-201, 211, 220, 221, 224, 269, 318, 353, 802

Endangered Species (Federally Listed) .....................................................................41, 114, 142, 149, 155, 360, 483-541

Endocrine Disrupter.......................................................................................18, 20, 64, 221, 247, 346, 349, 350, 352-353

EPSP synthase inhibitors ............................................................................................................................................... 147

Fluridone............................... xxx, 30, 31, 60, 62, 77, 80, 94-101, 119, 147, 178, 181, 183, 195, 199, 211, 212, 214, 224, 

229, 249, 261, 348, 355, 536, 607, 612, 617-623, 639

Formulations................................................................................................................................3, 27, 28, 33, 58, 609-616

Fungi ......................................................................................................................................................... (see Mushrooms)

Glyphosate .......................................xxix, 20, 30, 31, 60, 62, 77, 80, 81, 95-103, 119, 147, 178, 181, 183, 192, 193, 195, 

199, 211, 212, 214, 226, 236, 247, 263, 350, 353, 355, 536, 607, 612, 617-623, 640

Ground application.............................................................................................................................................. 71, 82, 353

Ground water .............................................................................................................................43, 145, 188-208, 211, 222

Half-life.....................................................................................................................................179-185, 194-198, 211, 224

Herbicide formulations / trade names.....................................................................................................(see Formulations)

Hexazinone ................................... xxx, 30, 31, 60, 62, 78, 80, 95-103, 119, 146, 181, 183, 192, 197, 199, 211, 213, 227, 

249, 263, 350, 537, 607, 613, 617-623, 641

Human health (risks)......................................................41, 86-92, 100-104, 114, 135, 192, 305, 313, 317, 321, 322, 325, 

328, 348-358, 785-786, 788-793, 801-802, 805-808, 809-811

Imazapic.......................... xxx, 30, 31, 34, 60, 63, 78, 80, 94-101, 119, 145, 181, 183, 197, 199, 211, 213, 224, 249, 261, 

278, 348, 537, 607, 614, 617-623, 642

Imazapyr ......................... xxx, 30, 31, 34, 60, 62, 78, 80, 95-103, 119, 145, 181, 183, 195, 199, 211, 212, 214, 227, 250, 

263, 351, 537, 607, 614, 617-623, 643

Inert ingredients............................................................................................................................ 20, 21, 64, 114, 229, 818

Integrated vegetation management ....................................................................................................................8, 27, 65-70

Invasive Plants................................................................................................................................................................ 131

Key species ............................................................................................................................................(see Target species)

Leaching........................................................................................................ 59-61, 144, 179-185, 194-202, 211, 220, 222

Manual method ....................................................................................73, 78, 150, 167, 231, 253, 293-294, 340, 344, 355 

Maximum application rates.................................................................................................. 59-61, 80, 81, 91, 94-104, 354

Mechanical method..............................................................................74, 78, 150, 167, 231, 253, 293-294, 340, 344, 355

Metsulfuron methyl................................. xxx, 30, 31, 34, 60, 63, 78, 80, 95-103, 119, 145, 181, 184, 198, 199, 211, 213, 

227, 250, 263, 351, 537, 607, 615, 617-623, 644

Mitigation measures, PEIS..........................................................................28, 41, 57, 91, 93, 116, 156, 457-467, 484-485

Mitigation measures, Potential.....................................................................................................................................50-53

Monitoring .................................................................................................................70, 133, 201, 208, 223, 238, 469-475

Mushrooms ..............................................................................................................................................145, 322, 332-334

Non-herbicide treatment methods....................................... xxiii, xxv, 15, 36, 39, 41, 73-76, 78, 136, 150, 151, 204, 215, 

231, 340, 342, 344

Noxious weeds.............................................................................................................................xxiv, 9, 131-139, 585-588

Oak habitats ............................................................................................................................................ 130, 152, 245, 274

Oregon State-listed noxious weeds......................................................................................................(see Noxious weeds)
Final Environmental Impact Statement: Index

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Pesticide use reports.................................................................................................................................................. 81, 118

Photosystem inhibitors.................................................................................................................................................... 146

Picloram.........................xxix, 30, 31, 60, 63, 77, 80, 81, 95-103, 119, 145, 181, 184, 192, 198, 199, 211, 213, 227, 248, 

263, 351, 355538, 607, 615, 617-623, 645

Potential vegetation..................................................................................................................................................141-143

Pounds of herbicides..................................................................................................................................... 77, 80, 81, 119

Prescribed fire .............................................................................. 76, 78, 150, 167, 231, 253, 273-278, 293-294, 340, 355

Prevention and education.................................................................................................................... 6, 8, 66, 67, 133, 359

Risk Assessment............................................................................ 14, 37, 41, 64, 80, 86-104, 114, 116, 605-607, 804-821

Recovery plan ................................................................................................................................................................... 31

Recreation sites..............................................................................31, 50, 77, 82, 83-85, 154, 304-310, 311-318, 338-342

Rights-of-Way..........................................................................................31, 50, 59-61, 77, 83-85, 154, 311-318, 338-342

Seed orchard........................................................................................................................................ 15, 31, 311, 313, 318

Special Status species (or Special Status fish, Special Status wildlife, Special Status plants)................ 10, 14, 31, 41, 91, 

94-99, 114, 142, 149, 155, 216, 235-238, 241, 242, 244, 360, 485-553

Spread rate ....................................................................................................................41, 42, 116, 133-139, 149, 594-597

Standard Operating Procedures...................................................................28, 41, 57, 91, 93, 115, 156, 457-467, 484-485

Sudden Oak Death ...................................................................................................................3, 11, 30, 156-163, 255, 322

Sulfometuron methyl ........................ xxx, 18, 30, 31, 34, 60, 63, 78, 80, 94-101, 114, 119, 145, 178, 181, 184, 198, 199, 

211, 213, 221, 222, 224, 250, 262, 349, 538, 607, 615, 617-623, 646

Survey and Manage......................................................................................................................................... 144, 155, 241

Synthetic auxins.............................................................................................................................................................. 145

Tank mixture ................................................................................................................... 62, 78, 83, 89, 116, 195, 230, 820

Target species and recommended herbicide controls....................................................xxix-xxx, 58-61, 589-594, 617-623

Tebuthiuron ......................... xxx, 31, 61, 62, 78, 80, 94-104, 119, 146, 181, 184, 198, 199, 211, 214, 226, 250, 262, 352, 

355, 356, 538, 607, 616, 617-623, 647

Treatment acres.................................................................................................... xxiii, 38, 40, 65, 77-78, 85, 13, 154, 340

Treatment costs............................................................................................................................ 12, 46, 161-162, 338-343

Treatment methods.......................................................................................................................................................68-76

Tribes .....................................................................................................................................13, 14, 22, 283-292, 330, 331

Triclopyr...................................................................................xxx, 17, 30, 31, 61, 63, 78, 80, 95-103, 119, 145-146, 178, 

181, 184, 193, 195, 199, 211, 212, 214, 227, 229, 250, 263, 351, 355, 356, 538, 607, 616, 617-623, 648

Typical application rates...................................................................................................... 59-61, 80, 81, 91, 94-104, 354

User group (exposure)......................................................................................................................................317, 331-334

Vectors of weed transmission.................................................................................................................. 132, 205, 210, 259

Weed Prevention ........................................................................................................................................(see Prevention)

Wind.................................................................................................................................114, 177, 179-180, 194, 220, 315

Work crew exposure.................................................................................................. 331-334, 354, 785-786, 788-793, 802
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

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