Final Environmental Impact Statement

xix

Summary

Introduction

This Final Environmental Impact Statement (FEIS) presents the environmental consequences, at the programmatic 

scale, of a proposal to increase the number of herbicides available to the nine Bureau of Land Management 

(BLM) districts in Oregon for use in their existing noxious weed, invasive plant, and other vegetation 

management programs. The BLM in Oregon has been limited to the use of four herbicides1 since 1987, and their 

use is limited to the treatment of noxious 

weeds (FEIS:32).

The BLM manages approximately 15.7 

million acres in Oregon, or about 25 percent of 

the land in the State. Vegetation management 

to meet the Federal Land and Policy 

Management Act’s public lands management 

policies and to satisfy the mandates of other 

laws, policy, and management plans takes 

place annually on thousands of acres of BLM 

lands in Oregon (FEIS:4). The BLM and its 

cooperators3 manage vegetation on thousands 

of acres per year to maintain or 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 are described in existing management plans, 

have been analyzed in existing National Environmental Policy Act (NEPA) documents, and are currently in use to 

achieve vegetation management objectives (FEIS:6). 

In 1984, the BLM was prohibited from using herbicides in Oregon by a U.S. District Court injunction issued in 

Northwest Coalition for Alternatives to Pesticides, et al. v. Block, et al. (Civ. No. 82-6273-E). The injunction 

stemmed from a court decision that the BLM had not conducted a worst-case analysis for the herbicides being 

used at that time. Following completion of an EIS addressing four herbicides for the treatment of noxious weeds, 

the injunction was modified by the court in November 1987 (Civ. No. 82-6272-BU). The injunction permits the 

use of the four herbicides analyzed, and limits their use to the control of noxious weeds (FEIS:3).

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 

including Oregon. Oregon cannot implement that decision, however, until and unless the District Court injunction 

is lifted (FEIS:3).

1 2,4-D, dicamba, glyphosate, and picloram

2 References in the Summary refer to the page numbers in the body of the Final EIS.

3 Cooperators: Leasees, permittees, and others with authorized uses or occupancy on BLM lands.

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

 xx

The BLM in Oregon has decided not to petition the court with the PEIS, but to prepare an Oregon-specific 

programmatic EIS, tiered to the PEIS. This EIS was prepared primarily: 

1) To address the U.S. District Court injunction in a single programmatic document, and; 

2) Because unlike the other western states, most of the herbicides proposed for use have not been used on 

Oregon BLM lands for more than 20 years, if at all. 

Neither of those conditions applies to the other 16 western states, which were using up to 20 herbicides for a full 

range of vegetation management objectives prior to the 2007 Record of Decision for the PEIS (FEIS:4). 

The EIS does not examine specific treatments. Additional NEPA analysis at the district or project level will 

analyze the effects of specific project proposals (FEIS:3).

What Action is Proposed?

The Proposed Action (Alternative 4) would add 9 of the nationally-approved herbicides west of the Cascades 

and 12 east of the Cascades4 to the 4 already in use (Table S-4). In addition, it would expand their use beyond 

noxious weed treatments to include: the control of all invasive plants; the control of pests and diseases; the 

control of native and other non-invasive vegetation in rights-of-way, administrative sites, and recreation sites; 

and, the treatment of vegetation to achieve habitat goals specified in interagency 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 (FEIS:7-8, 31-32). No aerial application would be permitted 

west of the Cascades (FEIS:31).

It is estimated that herbicide use would increase from 16,700 acres per year under the No Action Alternative 

(Alternative 2) to 45,200 acres per year under the Proposed Action (Alternative 4) (FEIS:78). Because newer, 

more target-specific herbicides would be used, the average pounds per acre of herbicide applied, would decrease 

about 30 percent (FEIS:80). All but 3,000 acres of the estimated increase would be east of the Cascades, and 

11,000 acres of the increase is estimated to be imazapic applications on invasive annual grasses, including 

medusahead and cheatgrass, primarily to help with restoration of native plants following wildfires or prescribed 

burns (FEIS:83). Approximately 9,000 acres of the increase would treat native and other non-invasive vegetation 

causing safety and maintenance issues on rights-of-way, administrative sites, or recreation sites (FEIS:83-84). 

These treatments are now done with non-herbicide methods (FEIS:84), and using herbicides would save about 

$1 million per year (FEIS:342), and have a collateral benefit of killing undetected invasive plants near roads and 

other high-use areas and thus preventing them from being moved elsewhere (FEIS:136-137). 

An estimated 5,700 acres of the proposed increase would go to improving habitat for Federally Listed or other 

Special Status species (FEIS:78), mostly in sagebrush habitats east of the Cascades (FEIS:256, 83). Herbicides 

would also be available to treat native plants to control exotic pests and diseases in State-identified control areas, 

like the area currently quarantined for Sudden Oak Death in southwestern Oregon (FEIS:31). In that area, tanoak 

stumps near Sudden Oak Death infestations would be treated to prevent resprouting, depriving the pathogen its 

preferred host (FEIS:162).

4 Districts east and west of the Cascades identified different program needs because of differences in vegetation types 

and weed occurrence.
Final Environmental Impact Statement

xxi

Why is the Action Needed?

Noxious weeds and other invasive plants are difficult to control. Many species simply cannot be controlled with 

manual and mechanical treatments alone because their roots are deep and readily re-sprout, because they are in areas 

where soil disturbance is not acceptable, access limitations prevent effective control, or because they would simply 

reseed into mechanically disturbed sites. Many plant species are not effectively controlled by the four herbicides 

currently available to BLM in Oregon. In spite of an aggressive Integrated Vegetation Management program using 

all available treatment methods, these plants are spreading, habitats are being degraded, and hazardous fuel buildup is 

increasing. About 1.2 million of the 15.7 million acres of BLM lands in Oregon are currently infested with noxious 

weeds at some level,5 and they are spreading at an estimated rate of 12 percent per year (Appendix 7). Ecological 

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

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

Status species; increased soil erosion and reduced water quality; reduced wilderness and recreation values; reduced 

soil productivity; and changes in the intensity and frequency of fires (FEIS:6-7). 

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 throughout the State and lead to plant quarantines on a variety of nursery plants (FEIS:7). 

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

Need for more effective vegetation control measures. 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 to make more herbicides available for use on public lands 

administered by the BLM in Oregon (FEIS:7). 

What Would it Mean Not to Meet the Need?

To answer that question, a No Action Alternative (Alternative 2) was analyzed. Noxious weeds would continue to 

spread at an estimated rate of 12 percent (144,000 acres per year), and infest about 5.9 million acres or one-third 

of the BLM lands in Oregon, in 15 years (FEIS:133, 138). Millions of acres of imperiled sagebrush habitat would 

be converted to medusahead and cheatgrass, which are invasive annual grasses with little habitat or forage value 

(FEIS:274) and prone to regular intense fires that remove all other vegetation and endanger rural communities 

(FEIS:277). The BLM would continue to try, without herbicides, to control tanoak on its portion of the State 

quarantine area for Sudden Oak Death in southwest Oregon. Tanoak is a prolific sprouter, and the continued 

persistence of Sudden Oak Death at the quarantine area is thought to be at least partially related to BLM’s 

inability to control that sprouting with herbicides (FEIS:161). If Sudden Oak Death escapes the quarantine area 

and spreads unchecked as it has in California, ecological damage from the loss of most tanoak and several other 

host trees throughout western Oregon and possibly into Washington would be severe. Such a spread would also 

5 “Infestations” range from monocultures of invasive weeds to a few stems per acre.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 xxii

cost Oregon’s nursery industry an estimated $28 to $259 million per year in lost export opportunities, quarantines, 

and cleaning (FEIS:160). 

Management of native and other non-invasive vegetation in rights-of-ways, administrative sites, and recreation 

sites would continue without herbicides, costing $1 million more per year than with herbicides (FEIS:342), and 

causing ground disturbances that exacerbate the spread of invasive plants (FEIS:136, 252). About 3,700 acres per 

year of habitat improvement opportunities for Special Status species would be forgone (FEIS:83-84).

A “no herbicides” Reference Analysis is also analyzed to help set a benchmark from which to compare herbicide 

use effects (FEIS:27). Overall, treatments without herbicides are more expensive and less effective at controlling 

noxious weeds (FEIS:136, 340). Under the Reference Analysis, noxious weeds are projected to spread to 8.6 

million acres in 15 years (about one-half of the BLM lands in Oregon) (FEIS:138).

Are There Other Alternatives that Would Meet the Need?

Three action alternatives are identified that would meet the Need and meet some or all of the Purposes. In 

addition to the Proposed Action (Alternative 4):

Alternative 3 would add eight and nine herbicides, west and east of the Cascades respectively, to the four currently 

being used (Table S-4). It would permit herbicides to be used on invasive plants other than noxious weeds, such 

as cheatgrass. This alternative would also make herbicides available to treat any vegetation as necessary to control 

pests and diseases in State-identified control areas, such as that for Sudden Oak Death in southwestern Oregon 

(FEIS:30). Herbicide use would be expected to increase from 16,700 acres under the No Action Alternative 

(Alternative 2) to 30,300 acres under Alternative 3 (FEIS:78), although total pounds of herbicide used would 

decrease about 35 percent (at the typical rate) because many of the additional herbicides are used in much lower 

quantities (FEIS:80). More than 80 percent (11,000 acres), of the increase would be to treat the invasive annual 

grasses medusahead and cheatgrass east of the Cascades, usually to facilitate native plant restoration following 

wildfire or prescribed fire (FEIS:83). The herbicides available under this alternative would be effective on almost all 

of the known invasive plants in Oregon (FEIS:136). Alternative 3 would meet the Need and many of the Purposes. 

Alternative 5 would add 14 herbicides to the four already being used (Table S-4), and make them available for 

any vegetation management objective except livestock forage or timber production. As with all the alternatives, 

treatments must be permitted by the product label and be consistent with the product’s Oregon registration 

(FEIS:28). The analysis estimates that herbicide use under this alternative would be about 50,000 acres per year, 

an increase of about ten percent (4,800 acres) from the Proposed Action (Alternative 4) (FEIS:78). Most of this 

increase would go to additional habitat improvements east of the Cascades (FEIS:83). All of the elements of the 

Proposed Action (Alternative 4) are included in this alternative, so both Alternatives 4 and 5 would meet the Need, 

and meet all eight Purposes to varying degrees.

What Factors Will be Used in Making the Decision Between Alternatives?

The decision by the BLM Oregon/Washington State Director will be based on the degree to which the selected 

alternative meets the Need and Purposes (FEIS:11). The Need is to better meet BLM’s noxious weed and other 

vegetation management responsibilities, there is an underlying need for more effective vegetation control 

measures (FSEIS:12).
Final Environmental Impact Statement

xxiii

The eight Purposes to be variously achieved by the selected alternative are:

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

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

native and other non-invasive vegetation. 

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

those included in the Special Status Species Program.

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

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

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

Department of Agriculture-identified control objectives.

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 (FEIS:8-12). 

What are the Effects of the Alternatives?

The Herbicides

In order to identify the potential effects of herbicide use, the annual 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 made predictions of annual 

treatment levels for the next 10 to 20 years assuming current budget trends (FEIS:77-78). Those totals are 

summarized below, displayed for BLM districts west and east of the Cascades (Table S-1).

Table S-1. Estimated Annual Treatment Acres with Herbicide and Non-Herbicide Methods, West (W) and

East (E) of the Cascades (FEIS:77-78)

Reference 

Analysis

Alternative 2 (No 

Action) Alternative 3 Alternative 4(Proposed Action) Alternative 5

Number of Herbicides 0 4 W: 12

E: 13

W: 13

E: 16 18

Herbicide Acres 0 W: 7,000

E: 9,700

W: 8,000

E: 22,300

W: 10,000

E: 35,200

W: 10,200

E: 39,800

Non-Herbicide Treatment 

Acres

W: 8,600

E: 33,500

W: 6,400

E: 22,400

W: 6,600

E: 21,500

W: 4,630

E: 12,075

W: 4,560

E: 10,430

Total Treatment Acres W: 8,600

E: 33,500

W: 13,400

E: 32,100

W: 14,600

E: 43,800

W: 14,630

E: 37,175

W: 14,760

E: 50,230

The potential for each of the 18 herbicides to have adverse effects is identified as risk. A Risk Assessment process 

established risk ratings for each herbicide for various categories of fish, wildlife, plants, workers, and the public 

based on specific (unguarded) exposure scenarios. Although the Proposed Action would result in some increased 

risk associated with the proposed increase in the use of herbicides, it would be limited by the implementation of 

Standard Operating Procedures and PEIS Mitigation Measures specifically designed to limit exposures (FEIS:93). 

Thus, the likelihood of actual adverse effects is low, and for every resource, the analysis indicates the effects of 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 xxiv

invasive weed spread are more adverse (Table 2-6, Purpose 1). The broader array of herbicides available for use 

would also allow for the selection of one that is most effective at accomplishing the weed control objective with 

the least amount of risk to nearby non-target resources including soil, air, and water (FEIS:11, 233).

Noxious Weed Effects and Rate of Spread

To help examine the effects of the spread of noxious weeds, the analysis also estimated the current spread rate for 

noxious weeds, and estimated how the different alternatives might be expected to change that rate (FEIS:135-137).

The list of adverse effects of noxious weeds and other invasive plants is long and varied (FEIS:133-134, 598-602). 

For example, they displace native species and degrade the ecosystems that depend upon them (FEIS:147-149). Many 

lack fibrous root systems or adequate foliage cover, so they do not protect soils from rain splash or overland flow 

(FEIS:178-179). Many have allelopathic effects (FEIS:281, 362). Many are poisonous to wildlife, livestock, 

wild horses, and burros (FEIS:270). Some invade stream banks but do not hold the soils, increasing siltation of 

spawning gravels and reducing water quality (FEIS:230). They displace riparian vegetation, reducing stream 

shading and the deposition of microfauna and detritus into streams that support the food chain (FEIS:230). They 

act as barriers that limit human and wildlife passage (FEIS:134). The invasive annual grasses increase fire 

occurrence and intensity, removing sagebrush plant communities (FEIS:139-104, 274). They make rangeland 

unusable, displacing forage for livestock grazing and destroying ranches (FEIS:264). They clog waterways and 

shade out native aquatic vegetation (FEIS:131).

Under Alternative 2 (No Action), herbicide and non-herbicide methods can be effective on 104 of the 120 Statelisted noxious weeds in Oregon. Treatments under this alternative are estimated to be 60 percent effective; that is, 

they eliminate the treated weed so it does not require retreatment an estimated 60 percent of the time (FEIS:136). 

This means 45,000 acres of annual treatments translates to 27,300 acres where the weed is controlled and would 

not spread (FEIS:137). Since these treatments focus on new satellite populations, new weeds, newly infested 

drainages, or the edges of expanding populations where weed spread would become exponential, 27,300 acres of 

control translates to 273,000 fewer infested acres in 15 years (FEIS:137-138).

Effective control is estimated at 30 percent for the Reference Analysis, where non-herbicide methods are only 

effective against about one-third of the noxious weeds. Alternative 3 includes effective controls for 116 of the 120 

State-listed noxious weeds in Oregon; effectiveness is estimated at 80 percent (FEIS:136). Finally, it is estimated 

that the 9,300 acres of native vegetation control in rights-of-way, administrative sites, and recreation sites in 

Alternatives 4 and 5 would incidentally control or avoid spreading undetected noxious weeds on 25 percent of 

those treatments, or 2,350 acres per year (FEIS:136-137). Applying these calculations to each of the alternatives 

results in the following 15-year noxious weed spread parameters (Table S-2).

Table S-2. Projected Annual Noxious Weed Spread and Acreage Change for Each Alternative (FEIS:137-138)

Alternative

Gross 

treatment 

acres

Treatment 

effectiveness

Effectively 

treated acres

Annual spread 

in 15 years

Total acres 

infested in 15 

years

15- year acre 

change from 

No Action

Portion of OR 

BLM lands 

infested 15 

years

Reference 

Analysis 42,100 30% 12,630 14% 8,600,000 +2.7 million 1/2

2 (No Action) 45,500 60% 27,300 12% 5,900,000 0 1/3

3 58,400 80% 46,720 7% 4,000,000 -1.9 million 1/4

4 (Proposed 

Action) 58,400 80%1 49,070 6% 3,700,000 -2.2 million 1/5-1/4

5 58,400 80%1 49,070 6% 3,700,000 -2.2 million 1/5-1/4 1

 Plus the 2,350 acres incidentally gained from treating native vegetation in rights-of-way, recreations sites, and administrative sites.
Final Environmental Impact Statement

xxv

Human Health and Safety

Nationally, the BLM has selected 18 herbicides from among hundreds available, picking those needed to 

accomplish the objectives while having the least risk to humans and the environment (FEIS:58). The additional 

herbicides that would become available under Alternative 3 are generally less toxic than those currently being 

used (FEIS:48-49, 94-104, 354-356). 

At typical rates, 2,4-D (Alternatives 2 through 5) is identified as having a moderate risk, and bromacil, diuron, and 

tebuthiuron (Alternatives 4 and 5) are identified as having risks ranging from none to high, depending upon the 

exposure scenario (FEIS:104, 354-356). Diquat has a low risk in some occupational scenarios, and triclopyr and 

diquat have a low risk in at least one of the accidental exposure scenarios evaluated (FEIS:102-103). All six of these 

herbicides have a PEIS Mitigation Measure that limits application to typical rates if feasible (FEIS:59-61).

Nearly all use of bromacil, diuron, and tebuthiuron would be east of the Cascades (FEIS:77), and bromacil and 

diuron would be used mostly where complete vegetation control is needed, such as for reducing fire hazard 

in unstaffed communications and other non-public developed sites, or to keep vegetation from growing into 

pavement edges (FEIS:62). Diquat is only available in Alternative 5 and projected use is low (FEIS:77); it is 

expected to be used only where one of the other five available aquatic herbicides would not work (FEIS:238).

Summary of the Major Effects of Each Alternative

While there is a potential for adverse resource and human health effects from various elements of the alternatives, 

the Standard Operating Procedures and PEIS Mitigation Measures would, by design and when coupled with sitespecific analysis and project design, reduce risk to the point where significant adverse effects at the programmatic 

scale would be unlikely (FEIS:93). 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 (FEIS:155-156, 235-238, 245).

The acres estimated to be treated by each herbicide or non-herbicide method under each alternative and displayed 

in Chapter 3’s Background for Effects Analysis section on Table 3-3 are integral to the following summary of the 

major effects of each alternative. Selected parameters for the alternatives relevant to the effects comparison are 

displayed on Table S-3.

Table S-3. Selected Parameters for Each Alternative Relevant to the Effects Comparison (FEIS:77-78, 80, 138)

Parameter Reference 

Analysis

Alt. 2

(No Action) Alt. 3

Alt. 4

(Proposed 

Action)

Alt. 5

Number of Herbicides Available 0 4 W: 12 

E: 13 

W: 13 

E: 16 18

Invasive Plant Herbicide Annual Treatment 

Acres/Lbs 0 16,700 acres23,010 lbs2

30,300 acres

14,830 lbs

30,300 acres

14,830 lbs

30,300 acres

14,830 lbs

Invasive Plant Non-herbicide Annual 

Treatment Acres 42,100 28,800 28,100 28,100 28,100

Native Plant Herbicide Annual Treatment 

Acres/Lbs 0 0 2501 14,900 acres19,865 lbs

19,700 acres

23,445 lbs

Rate of Spread at 15 years 14% 12% 7% 6% 6%

Difference in noxious weed infested acres 

in 15 year compared to the No Action 

Alternative

Up 2.7 million 0 Down 1.9 

million

Down 2.2 

million

Down 2.2 

million

1

 Pest and disease control in State-identified control areas only.

2

 Noxious weeds only.
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 xxvi

Reference Analysis: No Herbicide Use. A no-herbicides strategy would provide effective control for about 

one-third of the noxious weed species (FEIS:136), potentially precluding effective control around high priority 

Federally Listed and other Special Status species’ sites (FEIS:149, 235-236, 251-252), traditional gathering areas 

(FEIS:286-287), and high-public use sites where weeds could be picked up and transported (FEIS:132-133, 304). 

Control activities can be hazardous to those doing the weed treatments (FEIS:344-345), result in soil disturbance 

that can lead to reinvasion (FEIS:136), put cultural (FEIS:286-287) and soil resources (FEIS:185) at risk and 

cost more per acre (FEIS:340). Weed spread is predicted to increase under this strategy as the BLM and its 

neighbors become less successful (FEIS:139). Weeds are projected to infest 2.7 million more acres in 15 years 

than under the No Action Alternative (Alternative 2) (FEIS:138) – negatively affecting virtually every resource 

from wildlife to visual quality (Chapter 4). The human environment would suffer because of decreased water 

quality (FEIS:203-204), decreased wildlife (FEIS:254) and other elements of ecological diversity (FEIS:131-134), 

decreased access to natural resources (because of barriers like blackberries along streams) (FEIS:305), longterm changes including loss of species or populations (FEIS:151), loss of productivity (FEIS:281), and altered 

soil chemistry (FEIS:134). Social acceptance of this alternative is likely to be varied based on different views 

regarding the consequences of herbicide use and invasive weed spread (FEIS:324-327).

Alternative 2: (No Action) – Use 4 Herbicides to Treat Noxious Weeds Only. This alternative would provide 

effective control for 104 of the 120 State-listed noxious weed species in Oregon, but would not include tools 

effective on some invasive and noxious weeds including the invasive annual grasses (FEIS:136). Medusahead 

and cheatgrass occupy 600,000 and 5 million acres respectively (FEIS:271). Wildfire in these grasses would 

continue to convert remaining sagebrush habitats, decrease range carrying capacity for wildlife, wild horses, 

and livestock, and increase the risk of wildfire (FEIS:277). The four herbicides available under this alternative 

generally present some risk to one or more elements of the environment (FEIS:94-99), and many are used at a site 

for two or three consecutive years because they are not completely effective, compounding adverse environmental 

effects (FEIS:117). Repeatedly using the same herbicides also increases the likelihood that weeds resistant to that 

herbicide will take over the site (FEIS:155). Cooperative weed management strategies across ownerships would 

continue to be problematic since BLM neighbors use a wider variety of other herbicides (FEIS:153, 258). Current 

2,4-D use would continue to present a moderate risk to applicators (FEIS:356), non-noxious invasive weeds like 

cheatgrass cannot be treated with herbicides (FEIS:10, 152, 277), and noxious weeds would continue to spread 

at 12 percent or 144,000 acres per year on BLM lands in Oregon (FEIS:137). At this rate, noxious weeds are 

predicted to occupy one-third of all BLM lands in 15 years, causing proportionate losses in habitat (particularly 

for sage grouse and other sage steppe species), wild horse and livestock grazing, watershed protection, 

recreational opportunities, and other resource uses (Chapter 4). Social acceptance of this alternative would likely 

be fairly high (FEIS:324-327). Aerial application would be permitted west and east of the Cascades (FEIS:30).

Alternative 3: Use 12 (W) or 13 (E) Herbicides to Treat Invasive Weeds and Control Pests and Diseases. 

This alternative would go much of the way toward accomplishing most of the Purposes. The availability of eight 

and nine additional herbicides west and east of the Cascades respectively would provide effective controls for 

116 of the 120 noxious weed species (FEIS:136). The weed spread rate would eventually be reduced to 7 percent 

and infested acres in 15 years would be reduced by 1.9 million acres when compared to the No Action Alternative 

(Alternative 2) (FEIS:136-138). The BLM would have access to most of the herbicides used by neighbors, 

counties, and weed control boards, making cooperative projects more feasible and providing an incentive for 

better control across all ownerships (FEIS:153, 258). Having control tools effective on most noxious weeds 

in Oregon increases the likelihood that weed control efforts to protect Special Status plant and animal species’ 

habitats and traditional use areas would be successful (FEIS:149, 235-236, 251-252). Although acres treated with 

herbicides would increase (FEIS:78), pounds of herbicide (FEIS:80) and acres treated with moderate or high risk 

herbicides (FEIS:48-49) would both go down substantially. Potential adverse effects of noxious weeds to wildlife 
Final Environmental Impact Statement

xxvii

(FEIS:255), water (FEIS:204-205), and grazing- and recreation-dependent communities would all be reduced 

(FEIS:324-327). Air quality would be most adversely affected under this alternative (FEIS:168); the availability 

of imazapic would make prescribed burning a viable tool for restoring sage steppe habitats (FEIS:83, 255). Many 

wildfires and prescribed burns in invasive annual grasses simply return to these grasses unless an effective followup herbicide treatment and reseeding is used (FEIS:277).

The ability to use herbicides to help control Sudden Oak Death or other State-identified pests and diseases 

would provide the State and other cooperators a unified, potentially more successful, approach to protecting 

ecosystems and the nursery industry from this pathogen (FEIS:161-162). The cost per acre of effectively treated 

noxious weeds would be reduced 20 percent (FEIS:340). The acres treated with herbicides that are a moderate 

risk to applicators (2,4-D) would be reduced by about 50 percent (FEIS:356). Potential adverse effects to fish 

and wildlife would be reduced when compared to the No Action Alternative (Alternative 2) Table 2-5). Social 

acceptance of this alternative is likely to be high (FEIS:324-327). No aerial application would be permitted west 

of the Cascades (FEIS:30).

Alternative 4: (Proposed Action) – Use 13 (W) or 16 (E) Herbicides to Treat invasive Weeds plus Limited 

Additional Uses. This alternative is predicted to reduce noxious weed spread to 6 percent per year and result in 2.2 

million fewer infested acres in 15 years when compared to the No Action Alternative (Alternative 2) (FEIS:136-138). 

Herbicide use would reduce native and other non-invasive vegetation control costs in rights-of-way, administrative 

sites, and recreation sites by nearly $1 million per year (FEIS:342). These treatments would slightly reduce dust and 

vehicle emissions (FEIS:168) and reduce the likelihood of occupational injuries by reducing mechanical (chainsaw, 

etc.) treatments on steep wooded slopes when compared to the No Action Alternative (Alternative 2) (FEIS:331, 

344-345), but would increase the potential for an herbicide spill or misapplication. They would also preclude the 

need to separately spray noxious weeds along roads prior to mowing (FEIS:316), and incidentally control 2,350 

acres per year of unidentified or low-priority noxious weed populations along roadsides and other areas where there 

is a high likelihood of their being picked up and moved by vehicles (FEIS:136-137). Alternative 4 would also 

provide herbicides for about 5,700 acres of habitat improvement for Federally Listed and other Special Status species 

identified in interagency Conservation Strategies, 65 percent of which would be new opportunities currently deemed 

impractical without herbicides (FEIS:84). 

Of the additional herbicides added by this alternative, bromacil, diuron, and tebuthiuron have the highest risk 

to humans (FEIS:356), fish (FEIS:234), and for diuron, wildlife (FEIS:256). All but diuron are both pre- and 

post-emergent (FEIS:59-61), with most applications being restricted to east of the Cascades where they would 

be used to treat vegetation along roads, pipelines, pump stations, and other non-cropland areas (FEIS:77). Some 

of the tebuthiuron would be applied to sagebrush at low rates to improve sage grouse habitats (FEIS:256). PEIS 

Mitigation Measures restrict application to typical rate if feasible, specify avoiding aerial application of bromacil 

and diuron, and specify increased buffers on water and Federally Listed and other Special Status species’ habitats 

(Appendix 2). Finally, the social acceptance of using any herbicides to treat native vegetation along public roads 

would likely be less than the social acceptance for Alternative 3, at least west of the Cascades (FEIS:326). No 

aerial application would be permitted west of the Cascades (FEIS:31).

Alternative 5: Use 18 Herbicides to Treat Invasive Weeds and Meet Other Vegetation Management 

Objectives. This alternative would add 4,900 acres of herbicide use above what is proposed for Alternative 4 

(FEIS:78), and would make herbicides available for any treatment objective except livestock forage and timber 

production (FEIS:32). Most of this increase would be for additional habitat improvement projects east of the 

Cascades (FEIS:207). It would also make all 18 BLM-approved herbicides available throughout the State, with 

4,300 acres of the increase (when compared to Alternative 4) split between 2,4-D and imazapic (FEIS:77-78). 

Aerial application would be permitted west and east of the Cascades (FEIS:32). Additional habitats would benefit 
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 xxviii

as not all western juniper and rabbitbrush encroachment expected to be treated under this alternative is within 

Special Status species’ habitats covered by Alternative 4 (Proposed Action) (FEIS:257). Social acceptance of 

approving herbicide use for a fairly unspecified group of projects may not be high (FEIS:325-327). 

Can Any of the Adverse Effects be Mitigated?

The analysis indicates that by using the Standard Operating Procedures and PEIS Mitigation Measures 

(Appendix 2), the potential for adverse effects is low (FEIS:93). Where the potential for adverse effects is identified, 

potential mitigation measures are identified and will be considered by the decision-maker (FEIS:50-53). 

Many potential mitigation measures are variations on measures already adopted by the PEIS. Some suggest 

limitation on application rates or methods for several of the herbicides with risks identified in Risk Assessment 

documents (FEIS:50-53).

What Monitoring is Necessary?

Where the BLM is already using herbicides, formal monitoring is required by various BLM manuals. 

Environmental Protection Agency and Oregon Department of Agriculture annual reporting is also required, 

and relevant Endangered Species Act consultation documents typically include monitoring requirements. This 

monitoring includes implementation monitoring, relying in particular on Pesticide Use Proposal documents for 

every application, followed by Pesticide Application Records filled out within 24 hours of each application. Both 

documents have sufficient detail to determine if all planning and application requirements are met. The BLM 

is currently implementing a National Invasive Species Information Management System (NISIMS), which will 

provide tools for data collection and long-term Bureau-wide analysis and statistics for invasive plant infestations 

and treatments (Appendix 3). 

Effectiveness monitoring includes visiting every application site again after treatment, and maintaining weed 

maps. Biological control agent releases are also monitored, and monitoring is required of any BLM activity 

judged to have a moderate or high likelihood of spreading noxious weeds (Appendix 3). 

In addition to existing monitoring, the selection of one of the action alternatives could create a changed 

circumstance or condition (e.g. a concern over a potential environmental effect) that would suggest a need for 

additional monitoring. Those circumstances might include the use of the newly adopted herbicides with different 

ecological risks than the four herbicides currently used, more acres being treated, more acres being treated in 

proximity to people or susceptible environmental resources, more use of broadcast spraying with its potential for 

drift, or simply increasing the use of “new” herbicides above EIS-estimated levels as weed specialists become 

more familiar with their advantages. To respond to this potential need, the monitoring appendix suggests a 

five-year examination of weed spread to see if the selected alternative is making the expected difference, and 

monitoring of the application of herbicides identified in the analysis as high risk to a particular resource in a 

particular setting (Appendix 3).

These potential new monitoring needs are identified as optional in the Monitoring appendix (Appendix 3), and the 

decision-maker will identify selected monitoring when the Record of Decision is signed (FEIS:12).
Final Environmental Impact Statement

xxix

Which Alternative is Preferred?

Alternative 4, the Proposed Action, is the Preferred Alternative. It meets the Need, and meets all eight Purposes

to some degree. 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 (FEIS:50). 

The ability to treat 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 eradicate 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 (FEIS:50). 

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 (FEIS:50). 

Table S-4. Herbicides Available Under Each Alternative (FEIS:59-61)

Herbicide Characteristics and Target Vegetation

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

Selective; common targets include annual and 

biennial broadleaf weeds, kochia, whitetop, 

perennial pepperweed, Russian thistle and 

knapweed, sagebrush, and rabbitbrush.

√ √ √ √

Dicamba Selective; common targets include knapweeds, 

kochia, and thistles. √ √ √ √

Glyphosate 

Non-selective; common targets include grasses 

(including Italian ryegrass), sedges, broadleaf 

weeds, and woody shrubs.

√ √ √ √

Picloram 

Selective; common targets include perennial 

and woody species, knapweeds, starthistle, 

thistle, bindweed, leafy spurge, rabbitbrush, rush 

skeletonweed, and poison oak.

√ √ √ √

Additional Herbicides Proposed for Use in One or More of the Action Alternatives

Bromacil 

Non-selective; common targets include annual 

grasses and broadleaf weeds, cheatgrass, 

puncturevine, ragweed, wild oat, dandelion, 

quackgrass, and wild carrot. 

E √
Vegetation Treatments Using Herbicides on BLM Lands in Oregon

 xxx

Herbicide Characteristics and Target Vegetation

Reference 

Analysis

Alt 2

No Action Alt 3

Alt 4 

Proposed 

Action Alt 5

Chlorsulfuron 

Selective; common targets include thistles, wild 

carrot, giant horsetail, poison hemlock, Russian 

knapweed, marestail, perennial pepperweed, 

puncturevine, tansy ragwort, common tansy, 

common teasel, dalmation toadflax, yellow 

toadflax, whitetop, and dyers woad

E E √

Clopyralid 

Selective; common targets include thistles, 

common burdock, knapweeds, yellow 

starthistle, oxeye daisy, hawkweeds, prickly 

lettuce, dandelion, cutleaf teasel, kudzu, and 

buffalobur. 

√ √ √

Diflufenzopyr 

+ Dicamba 

Selective; common targets include knapweeds, 

kochia, and thistles. √

Diquat Non-selective; common targets include giant 

salvinia, hydrilla, and watermilfoils. √

Diuron 

Selective; common targets include annual 

grasses (including bluegrass) and broadleaf 

weeds, lambsquarters, kochia, and Russian 

thistle.

√ √

Fluridone Selective; common targets include hydrilla and 

watermilfoils. √ √ √

Hexazinone 

Selective; common targets include annual and 

perennial grasses and broadleaf weeds, brush, 

and trees.

√ √ √

Imazapic 

Selective; common targets include cheatgrass, 

leafy spurge, medusahead, whitetop, dalmation 

toadflax and russian knapweed.

√ √ √

Imazapyr 

Non-selective; common targets include annual 

and perennial broadleaf weeds, brush, trees, 

saltcedar, Russian olive, and tanoak.

√ √ √

Metsulfuron 

methyl 

Selective; common targets include whitetop, 

perennial pepperweed and other mustards, and 

biennial thistles.

√ √ √

Sulfometuron 

methyl 

Non-selective; common targets include 

cheatgrass, annual and perennial mustards, and 

medusahead.

√ √ √

Tebuthiuron Selective; common targets include sagebrush 

(thinning). E √

Triclopyr 

Selective; common targets include saltcedar, 

purple loosestrife, Canada thistle, tanoak, and 

Himalayan blackberry.

√ √ √

E - Only allowed in BLM Districts east of the Cascades