C

Asian Longhorned Beetle

Eradication Program

Draft Programmatic 

Environmental Impact 

Statement—March 2015

United States

Department of 

Agriculture

Marketing and 

Regulatory 

Programs

Animal and 

Plant Health 

Inspection 

Service

Asian Longhorned Beetle 

Eradication Program

Draft Programmatic Environmental 

Impact Statement—March 2015

Agency Contact:

Jim E. Warren, Ph.D.

Ecologist

Policy and Program Development

Animal and Plant Health Inspection Service

U.S. Department of Agriculture

4700 River Road, Unit 149

Riverdale, MD 20737–1238
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Table of Contents

Executive Summary ...............................................................................v

I. Purpose of and Need for Action............................................................1

A. Background ....................................................................................2

1. Description of ALB ....................................................................2

2. Economic Impacts of ALB in the United States..........................7

3. Existing and Projected Ecological Impact in the 

United States and Elsewhere....................................................9

B. Public Involvement........................................................................11

1. Prior EAs Published by the Agency and Results from

Public Comments ...................................................................11

2. Past Agency Outreach Efforts on ALB Issues .........................11

3. Locations of Addressed Issues Raised by Stakeholders .........12

C. Decision Framework.....................................................................14

1. No Action ................................................................................15

2. Removal of Infested Trees ......................................................15

3. Full Host Removal...................................................................15

4. Insecticide Treatment..............................................................15

5. An Integrated Approach ..........................................................15

D. Scope of this Document and NEPA Requirements .......................16

E. Consultations................................................................................16

II. Alternatives.........................................................................................19

A. Quarantine ...................................................................................19

B. Survey..........................................................................................20

1. Level 1 Survey (Core Survey).................................................21

2. Level 2 Survey (Buffer)...........................................................21

3. Level 3 Survey (High Risk Survey ..........................................22

4. Secondary Survey ..................................................................23

C. Alternatives Evaluated in this EIS.................................................23

1. No Action................................................................................26

2. Removal of Infested Trees......................................................26

3. Full Host Removal ..................................................................28

4. Insecticide Treatment .............................................................29

5. An Integrated Approach (Preferred Alternative) ......................30

D. Alternatives Considered but Not Included in this EIS....................31

1. Use of Other Chemical Control Agents...................................31

2. Other Integrated Pest Management/Suppression 

Strategies ............................................................................. 31

III. Affected Environment.........................................................................33

A. Affected Forest Communities .......................................................33

B. Affected Water Resources............................................................35

1. Water Quality..........................................................................36

2. Interactions of Soils with Water Quality...................................37

Table of Contents i.
C. Affected Soil.................................................................................38

1. Soil Types of the United States...............................................38

2. ALB-Host Species and Soil Quality.........................................39

3. Soil Erosion ............................................................................40

D. Air ................................................................................................40

E. Affected Biological Organisms......................................................43

F. Affected Economic, Social, and Cultural Factors..........................47

1. Market Factors .......................................................................47

2. Timber....................................................................................47

3. Maple Syrup ...........................................................................50

4. Tree Nurseries........................................................................51

5. Non-Market Factors................................................................51

6. Social Factors.........................................................................52

7. Cultural Factors ......................................................................53

IV. Environmental Consequences............................................................55

A. Program Alternatives.....................................................................55

1. Alternative 1: No Action ..........................................................55

2. Alternative 2: Removal of Infested Trees ................................65

3. Alternative 3: Full Host Removal.............................................73

4. Alternative 4: Infested Tree Removals and Insecticide

 Treatment of High-Risk Host Trees..........................................76

5. Alternative 5: An Integrated Approach (Preferred 

Alternative)...............................................................................85

6. Cumulative Impacts..................................................................87 

B. Special Programmatic Considerations...........................................93

1. Applicable Environmental Statutes ...........................................93

2. Mitigation and Risk Reduction ................................................100

3. Program Monitoring ................................................................102

4. Irreversible and Irretrievable Commitment 

of Resources ..........................................................................103

Appendices

A. Preparers

B. List of ALB NEPA Links

C. ALB Annotated Host List

D. Assessment of Greenhouse Gas Fluxes and Climate Change Impacts 

Related to ALB 

E. Herbicide Human Health and Ecological Risk Assessment

F. Imidacloprid Human Health and Ecological Risk Assessment

G. Acronyms and Glossary

H. References

I. Distribution List

J. Index

ii. Table of Contents
Tables

2–1 Overview of Alternatives in this EIS.

3–1 GHG Emissions in the United States Allocated by Source.

3–2 Threatened or Endangered Species that Occur in Areas the 

Program is Operating.

3–3 Volume of Sawtimber (ALB-host Species) in Northeastern States 

and the State of Ohio—2012.

3–4 Volume of Roundwood Products (ALB-Host Species) in the 

Northeastern States—2006.

3–5 Value of Selected Timber Products for Species and State—2006

3–6 Maple Syrup Production 2010–13.

4–1. ALB Eradication Program Historical Cost-Share Contributions 

(from 1997 to 2009 (thousands of dollars)).

Figures

I–I Adult Asian longhorned beetle.

I–2 Susceptibility potential for the Asian longhorned beetle in the 

United States based on the basal area for Acer (maple).

3–1 Forest areas potentially at risk to Asian longhorned beetle

3–2 U.S. hardwood log exports for select ALB-host species, 1989–2008.

4–1. Direct and indirect effects of ALB establishment to representative 

aquatic and terrestrial organisms.

4–2 Federally listed threatened and endangered species by county that 

co-occur with ALB-host trees in the Northeastern United States

Table of Contents iii.
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iv. Table of Contents
Executive Summary

The U.S. Department of Agriculture, Animal and Plant Health Inspection 

Service (APHIS) has prepared a draft programmatic environmental impact 

statement (EIS) for the Asian Longhorned Beetle (ALB) Eradication 

Program. ALB is a serious insect pest of certain hardwood tree species, 

with the potential to cause significant economic and environmental 

impacts if allowed to establish and spread throughout the United States. 

The Program is a cooperative effort between Federal and State agencies to 

identify and eradicate ALB infestations in the United States. To date, 

there have been ALB outbreaks in five States including Illinois, 

Massachusetts, New Jersey, New York, and Ohio. This draft ALB EIS 

considers potential environmental impacts from each of the alternatives 

proposed for the APHIS ALB Eradication Program, should ALB be 

discovered elsewhere in the continental United States. APHIS can tier 

subsequent site-specific environmental assessments (EAs) to this EIS, 

incorporating, by reference, analyses included in this document, thus 

reducing response time for APHIS to act on new detections. In addition, 

this EIS will provide the interested public with a programmatic analysis of 

the potential for environmental impacts from the alternatives available to 

APHIS to eradicate ALB from the United States. 

On August 16, 2013, APHIS published a notice in the Federal Register 

(FR) describing its intent to prepare a programmatic EIS for the ALB 

Eradication Program (78 FR 50022–23, August 16, 2013). The public was 

invited to comment on the proposed EIS; APHIS received 27 comment 

letters during the 45-day scoping period. Comments were received from 

the public, non-governmental organizations, and State agencies regarding 

different aspects of the ALB Eradication Program. APHIS has addressed 

the comments to the extent possible in this draft EIS.

Five alternatives were evaluated in this draft EIS. The analysis is a

general assessment of the alternatives, and their potential impacts to 

human health and the environment. The five alternatives include: 

(1) No Action—APHIS would implement quarantine restrictions but no 

eradication program; 

(2) Removal of Infested Trees—APHIS would implement quarantine 

restrictions and remove only ALB-infested trees; 

(3) Full Host Removal—APHIS would implement quarantine restrictions 

and remove only ALB-infested trees, and all high-risk host trees up to 

a 1⁄2-mile radius of infested trees; 

Executive Summary v.
(4) Insecticide Treatment—APHIS would implement quarantine 

restrictions, remove all infested trees, and chemically treat all highrisk host trees with an insecticide up to a 1⁄2-mile radius of infested 

trees; and 

(5) An Integrated Approach—APHIS would implement quarantine 

restrictions, remove infested trees, and use a combination of removal 

and insecticide treatments of high-risk host trees (preferred 

alternative).

The potential impacts from the implementation of the five alternatives 

suggest that there could be some effects to the human environment. The 

largest impacts, both economic and environmental, are expected to occur 

under the no action alternative, which would effectively allow ALB to 

become established and spread throughout the United States. Economic 

impacts related to the establishment of ALB in the United States in 

forested areas include a decrease in revenues related to various timber 

markets, maple syrup production, and tourism, where ALB-host trees are a 

primary component of impacted forests. Economic losses related to ALB 

establishment in urban areas include tree replacement costs and impacts to 

property value. Environmental impacts are anticipated for terrestrial and 

aquatic wildlife that are dependent upon ALB-host trees. The extent of 

the impacts will vary based on the prevalence of ALB-host trees in forests,

and whether affected species depend on ALB-host trees to meet critical 

periods in their life history. The implementation of quarantine, in 

association with an eradication program, will reduce these impacts to 

varying degrees, depending on which eradication approach is used.

The potential impacts from the proposed alternatives, and applicable 

environmental laws and statutes, are discussed on a programmatic basis in 

this draft EIS. No site-specific eradication projects will be implemented 

as a direct result of the decision that will follow this EIS. The decision to 

implement any treatment project will be made after site-specific EAs are 

conducted and documented, in accordance with the implementing 

procedures of the National Environmental Policy Act of 1969 (NEPA).

Site-specific EAs will evaluate similar topics as there may be changes 

over time in the available data regarding this analysis, as well as 

applicable laws and statutes. 

Selection of the preferred alternative allows the Program to implement a 

proven eradication program that has been successful in other ALB 

eradication efforts in the United States. The preferred alternative 

integrates survey and quarantine with the removal of infested trees, and 

site-specific management of high-risk host trees, thus allowing the 

Program the greatest flexibility in responding to ALB outbreaks and 

achieving eradication. 

vi. Executive Summary
I. Purpose of and Need for Action

The Asian longhorned beetle (Anoplophora glabripennis (Motchulsky))

(ALB) is a foreign wood-boring beetle that threatens a wide variety of 

hardwood trees in North America. The introduction of ALB into the 

United States was likely from infested wood pallets, and other wood 

packaging material (WPM), accompanying cargo shipments from Asia. 

The purpose of the proposed action is to protect the forests and trees of the 

United States from the adverse effects of ALB. 

Why is there a need to eradicate this pest?

There is a need to eradicate ALB wherever it occurs because it is 

potentially one of the most destructive and costly invasive species to enter 

the United States. The beetle bores through the tissues that carry water 

and nutrients throughout the tree, causing the tree to weaken and 

eventually die. Symptoms occur approximately 3 to 4 years after 

infestation, and tree death can occur in 10 to 15 years, depending on site 

conditions. Infested host trees do not recover and regenerate (APHIS, 

2009). Tree mortality caused by ALB has been noted in countries where 

the beetle is endemic, and where it has been introduced (Haack et al., 

2010). In the United States, foresters have observed ALB-related tree 

mortality in New York, New Jersey, Massachusetts, Ohio, and Illinois.

The insect threatens urban and suburban shade trees, and recreational and 

forest resources valued at hundreds of billions of dollars (Nowak et al., 

2001). In addition, ALB is likely to have negative impacts on forestdependent terrestrial and aquatic species, including threatened and 

endangered (T&E) species; soil and water quality could also be 

significantly impacted in forested areas where ALB-host trees are 

dominant (APHIS, 2009).

Who has authority to act?

The U.S. Department of Agriculture (USDA), Animal and Plant Health 

Inspection Service (APHIS) has a broad mission area that includes 

protecting and promoting U.S. agricultural health, and protecting and 

promoting food, agriculture, natural resources, and related issues. 

Specifically, the Plant Protection Act of 2000 (7 United States Code

(U.S.C.) 7701 et seq.) provides the authority for APHIS to take actions to 

exclude, eradicate, and control plant pests, including ALB. Under this 

authority, APHIS works to prevent new infestations of ALB from entering 

the United States by regulating WPM, by restricting movement of items 

that may be infested with ALB (known as regulated articles) from areas

I. Purpose of and Need for Action 1
under quarantine for ALB, and by conducting programs to eradicate ALB

where it is found in the United States. 

This programmatic environmental impact statement (EIS) discloses the 

different methods and alternatives that APHIS can use to eradicate ALB 

from areas it occurs in the contiguous United States.

Why do this environmental impact statement?

As a Federal Government agency subject to compliance with the National 

Environmental Policy Act of 1969 (NEPA) (42 U.S.C. 4321–4347), 

APHIS prepared this EIS in accordance with the applicable implementing

and administrative regulations (40 Code of Federal Regulations (CFR) §§

1500–1508; 7 CFR §§1b, 2.22(a)(8), 2.80(a)(30), 372). This 

programmatic EIS presents program alternatives APHIS could adopt as 

part of the ALB Eradication Program, and examines the potential 

consequences of implementing them.

APHIS has prepared 14 site-specific environmental assessments (EAs),

since 1996, for ALB eradication programs and research studies in Illinois, 

New York, New Jersey, Massachusetts, and Ohio (appendix B). This EIS 

will consider potential environmental impacts from the APHIS ALB 

Eradication Program should ALB be discovered elsewhere in the 

contiguous United States. APHIS can tier subsequent site-specific EAs to

this EIS, incorporating by reference analyses included in this document, 

thus reducing response time for APHIS to act on new detections, should 

these occur. In addition, this EIS will provide the interested public with a 

programmatic analysis of the potential for environmental impacts from the 

alternatives available to APHIS to eradicate ALB from the United States. 

A. Background 

a. Life Cycle 

ALB is in the wood-boring beetle family Cerambycidae. Adults are 1 to 

11⁄2 inches in length with long antennae, and are shiny black with small 

white markings on the body and antennae (figure 1–1).

Adult females chew depressions into the bark of various hard-wood tree 

species in which they lay (oviposit) their eggs. Eggs hatch within 2 weeks 

of oviposition (Haack et al., 1997; EPPO, 1999). After hatching, small 

white larvae bore into the tree, feeding on the vascular layer which

transports nutrients and water throughout the tree. Larvae molt and can go 

through as many as 13 instar stages (Keena, 2008). The larvae continue to 

feed deeper into the tree's heartwood, forming tunnels (or galleries) in the 

trunk and branches. 

1. Description

of ALB

2 I. Purpose of and Need for Action
Figure 1–1. Adult Asian longhorned beetle.

Over the course of a year, a larva will mature and then pupate inside the 

tunnels formed by the larva within the tree. The pupal stage lasts 13 to 

24 days (Lingafelter and Hoebeke, 2002; Haack et al., 2006). From the 

pupa, an adult beetle emerges, chewing its way out of the tree, forming 

FKDUDFWHULVWLFURXQGH[LWKROHVDSSUR[LPDWHO\ǪLQFKLQGLDPHWHU$IWHU

emerging from the tree, adults will feed on leaves and bark for 10 to 

14 days before mating and laying eggs (Keena, 2002; Smith et al., 2002).

Adults tend to remain on the tree from which they emerge, resulting in 

infestation by future generations (EPPO, 1999). Adult activity is usually 

observed from May to July, although adults have been observed from 

April to December (Haack et al., 2010).

The damage from larvae burrowing into the tree and adults burrowing out 

of the tree cuts off nutrient flow and weaken the tree. The tree will 

eventually die if the infestation is severe enough. Sawdust-like debris and 

insect waste (called frass) from the insect’s burrowing activity may be 

found at the base of infested trees. Infested trees are also prone to 

secondary attack by disease and other insects. 

In most locations, ALB produces one generation per year; however, in 

other countries where the pest is established, the number of annual 

generations varies with climate and latitude. For example, in northern 

China, one generation takes 2 years to develop (EPPO, 1999; Lingafelter 

and Hoebeke, 2002). Because ALB can overwinter in multiple life stages 

(egg, larval, and possibly pupal stages), adult emergence is staggered over 

time, resulting in adults emerging, feeding, mating, and laying eggs 

(ovipositing) throughout the summer and fall (Haack et al., 2006).

I. Purpose of and Need for Action 3
b. Hosts

There are 13 genera of host trees that APHIS regulates for ALB and are 

considered high-risk hosts: Acer (maple and box elder), Aesculus (horse 

chestnut and buckeye), Salix (willow), Ulmus (elm), Betula (birch), 

Albizia (mimosa), Celtis (hackberry), Cercidiphyllum (katsura tree), 

Fraxinus (ash), Koelreuteria (golden raintree), Platanus (sycamore and 

London planetree), Sorbus (mountain ash), and Populus (poplar) (APHIS, 

2009), 7 CFR 301.51–2). These trees are hosts because the ALB can 

derive its food supply and complete its life cycle. A host tree is still a host 

even if it is not infested. Acer is the most commonly infested tree genus in 

the United States, followed by Ulmus and Salix (Haack et al., 2010). Acer,

Aesculus, Salix, Ulmus, and Betula are considered preferred ALB-hosts 

(APHIS, 2008). Other regulated genera are considered rare or occasional 

hosts, including Albizia, Celtis, Cercidiphyllum, Fraxinus, Koelreuteria,

Plantanus, Sorbus, and Populus (APHIS, 2008) (see appendix C). APHIS 

expects to remove Celtis from the list of regulated host trees based on 

observation that this is not a host tree. A recent study indicates that ALB 

egg laying (oviposition) and reproductive success are higher on red maple 

(Acer rubrum), compared to Norway maple (A. platanoides) or sugar 

maple (A. saccharum) (Dodds et al., 2014). (See appendix C for an 

annotated list of ALB hosts.)

c. Dispersal and Spread

(1) Human-Mediated Spread

ALB entered the United States, most likely, in WPM from Asia. USDA–

APHIS regulations in 7 CFR §319.40–1 define WPM as “wood or wood 

products (excluding paper products) used in supporting, protecting, or 

carrying a commodity (includes dunnage).” WPM (e.g., pallets, crates, 

etc.) is made from low-grade lumber with higher moisture content than 

seasoned wood or heat-treated wood. Low-grade lumber may be of low 

quality due to pest damage (Cavey, 1998). (Bush et al., 2002) reported

that hardwood species accounted for about two-thirds of the total wood 

used for pallets during the 1990s. The National Plant Protection 

Organizations (NPPO) recognize WPM as a pathway for pest movement 

between countries.

In response to the threat posed by untreated WPM, the Commission on 

Phytosanitary Measures of the International Plant Protection Convention 

(IPPC) of 2002 adopted International Standards for Phytosanitary 

Measures No. 15 (ISPM 15) titled “Guidelines for Regulating Wood 

Packaging Material in International Trade” (FAO, 2002 ). ISPM 15 

prescribes either heat treatment or fumigation for all WPM to mitigate risk 

of pests. WPM subjected to these approved measures is required to 

4 I. Purpose of and Need for Action
display a mark verifying compliance. Since September 16, 2005, the 

United States began full enforcement of ISPM 15, requiring either 

fumigation or heat treatment for all WPM entering the United States from 

any country; however, compliance with ISPM 15 is not required for WPM 

used domestically. WPM made from infested wood and used in domestic 

shipments would continue to be a potential source of spread.

Once ALB is present in the United States, it can move through domestic 

pathways. For example, movement of recently felled trees could carry

ALB, and potentially spread it a long distance from the infested site. The 

level of risk depends on the end use of felled trees, that is, chipping for 

mulch, disposal in landfills, incineration, and so on. Although ALB 

prefers to infest branches in the tree crown rather than the trunk, lumber 

and saw logs are, nonetheless, a potentially important pathway to spread 

ALB. 

The production and distribution of fuel wood (this category includes 

firewood) also could transport infested material long distances. Moreover, 

many people use fallen limbs or felled trees from their private property as 

firewood, sometimes transporting and using these on vacations or in other 

homes. While educational programs and quarantine regulations in 

affected areas seek to prevent this kind of spread, this transport may still 

occur. Transport of infested stumps and limbs for disposal are another 

potentially important ALB pathway, although the level of risk depends on 

how municipal solid waste is treated in the infested area. ALB can also be 

transported through the movement of infested nursery stock. 

Establishment of quarantines and quarantine regulations, which restrict the 

movement of woody material, reduce the likelihood of human-mediated 

spread of ALB. In quarantine areas in the United States, businesses or 

individuals working with trees or related products (e.g., firewood) must be 

under a compliance agreement with APHIS. These include landscapers,

tree pruning and tree removal companies, firewood dealers, pallet 

distributors, nurseries, and sanitation workers, as well as other municipal 

or community services and associated contractors. The ALB Eradication 

Program provides a debris disposal site for use by companies under 

compliance agreement, and by municipalities within the quarantine area. 

Private residents have to secure the services of a company under 

compliance to remove host material from their property. All host material 

for disposal, regardless of infestation, must be chipped prior to leaving the 

quarantine area. Chipping infested trees is effective in destroying ALB 

(Wang et al., 2000). Nursery stock in the quarantine area is subject to 

inspection. Uninfested host material in the nursery trade may leave the 

quarantine area if accompanied by a certificate of inspection and approved 

I. Purpose of and Need for Action 5
permits. Any infested host material found in the nursery trade must be 

chipped.

(2) Natural Spread

Adult beetles are prompted to move when the density of beetles in a given 

area reaches high levels (Williams et al., 2004), or when they are in search 

of a mate (Bancroft and Smith, 2005). ALB is a weak flier therefore

spread through natural means (self-motility) is a minor contributor to 

spread potential (Bancroft and Smith, 2005).

Various studies have examined the distance ALB travels per day. Smith et 

al. (2001) found, on average, that adult females and males move 

23 meters/day (m/day) and 17 m/day, respectively. Dispersal rates may be 

affected by the age of the beetle, population density, temperature, 

proximity of host trees, and other factors. In a mark-recapture study, 

Smith et al. (2004) found the median daily dispersal rate for both sexes 

was 30 m/day (range of 11 to 56 m). Williams et al. (2004) tracked adult 

beetles using harmonic radar, and found movement rates were 1.9 m/day 

for females and 3.7 m/day for males. Most beetles tended to move in one 

direction and rarely backtracked. In a mark-recapture study, Smith et al. 

(2004) found the median daily dispersal rate for both sexes was 30 m/day 

(range of 11 to 56 m). Williams et al. (2004) tracked adult beetles using 

harmonic radar, and found movement rates were 1.9 m/day for females 

and 3.7 m/day for males. Most beetles tended to move in one direction 

and rarely backtracked. Bancroft and Smith (2005) estimated a

probability of 62 percent that beetles move from the tree on which they 

were last recorded to a tree nearby. They characterized daily movement at 

20 m/day. 

Smith et al. (2001) measured a maximum ALB dispersal distance 

(including that of female beetles carrying mature eggs) of 1,442 m. In 

another mark-recapture study, Smith et al. predicted that “98% of beetles 

were recaptured at distances <920 m from the release point.” Beetles were 

recaptured at the most outlying sampling points (1,000 to 1,080 m from 

release point), and even at distances up to 2,600 m from the release point 

(Smith et al., 2004). Of the gravid (carrying eggs) females, 86 percent

were recaptured within 1,080 m, and 77 percent were recaptured within 

600 m. Eight gravid females were recaptured at distances greater than 

2,000 m (2 kilometers (km) (Smith et al., 2004).

d. Geographic Distribution: Current and Projected

ALB is native to China and Korea (Cavey, 1998; Lingafelter and 

Hoebeke, 2002), but it was not considered a pest in natural forests there 

(Hajek, 2010). The distribution and abundance of ALB increased 

6 I. Purpose of and Need for Action
2. Economic 

Impacts of 

ALB in the 

United States

dramatically throughout China because in the 1960s and 1970s the 

Chinese government supported reforestation programs using fast-growing

poplar trees, many of which were susceptible to ALB (Cao et al., 2010;

Hajek, 2010). Millions of ALB-infested trees have been cut in China over 

the past decades, and it is likely that this wood was used as WPM (Haack 

et al., 2010). Because of the increase in trade with Asia that involved 

WPM, ALB was introduced to Austria, Belgium, Canada, France, 

Germany, Italy, Japan, the Netherlands, Switzerland, United Kingdom, 

and the United States (Carter et al., 2010; Haack et al., 2010; EPPO, 

2014). Belgium and Japan have eradicated the insect (EPPO, 2014).

Peterson et al. (2004) predicted the potential distribution of ALB in North

America based on the climatic factors in its native distribution. Their

models suggest, “. . . the species has the potential to invade much of 

eastern North America, but only limited areas in western North America, 

and that a focus of initiation of invasion is likely to lie in the area south of 

the Great Lakes.”

Haack et al. (1997) overlaid the distribution of ALB in China (21 °N to

43 °N) onto North America, and determined that the range coincides with 

the span from southern Mexico to the Great Lakes. Keena (2006) noted 

that summer temperatures, throughout most of the lower 48 States, should 

support beetle survival and reproduction. Based on preferred host 

availability, Nowak et al. (2001) estimated the percentage of trees and 

number of trees at risk in nine U.S. cities, including one city in the 

Southeast and one city in the West. They estimated that 20 percent (or 

1.8 million) trees in Atlanta, Georgia were at risk of infestation, and in 

Oakland, California, 12 percent (or 0.19 million) trees were at risk. They 

also estimated that cities in the Northeast, such as Boston, Massachusetts 

and Syracuse, New York may lose as much as 60 percent of their trees 

should ALB be introduced and allowed to spread. All available studies 

indicate that ALB is able to survive and reproduce in any location within 

the lower 48 States that has host trees (APHIS, 2009). (See figure 2–1 for

the ALB susceptibility potential for Acer (species of maple) in the United 

States.)

The spread of ALB beyond the current isolated outbreaks could have

severe economic effects. Although it is difficult to estimate the extent of

expected impacts over time, it is clear that several industries in the

Northeastern United States would be affected if ALB were to spread

beyond the current areas of infestation to other urban and forested areas.

These impacts would include not only the loss of urban trees at an

estimated cumulative cost of at least $948 million in cities in the

Northeastern United States, but also losses in several other industries, as

well as non-market economic losses (Nowak et al., 2001).

I. Purpose of and Need for Action 7
The timber industry produces over $178 million of products from host 

species annually in the Northeastern United States alone. Maple syrup

production was worth nearly $67 million in 2010. The tourism 

industries in nine of the Northeastern States reported revenues around 

$143 billion in 2012. In addition, sales of deciduous shade trees were

estimated at an additional $56 million for eight of the Northeastern States

(including Ohio). The annual production values at risk in these three

industries alone are significantly larger than the projected annual budget

of the ALB Eradication Program.

Figure 1–2. Susceptibility potential for the Asian longhorned beetle in the United States based 

on the basal area for Acer (maple). Source: (FS, 2009a).

 While the expected economic losses in forest-related products in the

Northeastern United States and Ohio are large, previous research indicates

non-market economic losses due to forest-related pests are expected to be

larger than any market losses. This loss of host trees would have

economic impacts in urban, suburban, and forested environments due to 

the loss of aesthetic and ecosystem benefits. Previous studies have shown

that the presence of healthy trees increases property values by 2 to 6

8 I. Purpose of and Need for Action
3. Existing and 

Projected 

Ecological 

Impact in the 

United States 

and 

Elsewhere 

percent (Morales et al., 1976; Anderson and Cordell, 1988; Dombrow and 

Sirmans, 2000). In addition, the loss of host species would likely decrease

fall foliage tourism in the Northeastern United States, which relies on a

number of host species for the vibrant fall color displays. Many

communities in the Northeastern States and the State of Ohio generate 

significant economic activity from fall foliage tourism, and would be

unlikely to recover from the loss of so many of the species that provide fall

colors. Other non-market impacts would be likely due to the loss of

recreational benefits and ecosystem service provisions. The widespread

establishment of ALB would also likely affect U.S. trade in green lumber,

and live trees and shrubs if importing countries establish quarantines or

other restrictions for ALB.

Although a complete cost-benefit analysis of the current Program is 

outside the scope of this EIS, even a relatively modest annual decrease in

only two forest-related industries would result in economic losses more

than sufficient to justify the anticipated costs of the ALB Eradication 

Program. The market losses in the timber and maple syrup industries do 

not include any impacts related to nursery stock or non-market losses

related to urban trees and other aesthetic and ecosystem impacts.

Considering that non-market losses are likely to be greater than any market

losses, the benefits of an eradication program would outweigh program

costs with a relatively small annual loss in the markets for forest products

(APHIS, 2009). Further research to quantify these non-market benefits of

eradication would help to strengthen this conclusion.

Widespread establishment of ALB in the United States will cause 

significant ecological damage, affecting terrestrial and aquatic fauna and 

flora. Multiple factors dictate the extent of damage and its impact on 

ecological community function. In cases where the host trees are not a 

dominant component of the forest stand, the impacts may be less; 

however, in locations where host trees occur in high density and are 

keystone species within that particular forest type, the impacts are almost 

certain to be significant. The loss of keystone tree species and the 

associated cascading impacts to ecosystem function have been 

documented in other forest types where invasive forest insect pests were 

introduced (Ellison et al., 2005). The spatial and temporal factors related 

to an ALB infestation also will dictate the magnitude of impacts to 

ecosystems, particularly for species that are dependent on these habitats at 

critical periods in their life history.

I. Purpose of and Need for Action 9
History of APHIS Eradication Actions and Other Regulatory

Actions Against ALB

The first detection of ALB in the United States was in Brooklyn, New 

York, in 1996, although the actual date of introduction is much earlier.

Shortly after, another infestation was detected in Amityville on Long 

Island. Since then infestations have been found in Islip on Long Island, in 

Queens, in Manhattan and on Staten Island, including Pralls Island. Most 

recently, an infestation was detected in portions of Babylon Township on

Long Island. 

Additional outbreaks occurred in Chicago, Illinois in 1998, and in 

Middlesex and Union Counties in New Jersey in 2002 (APHIS, 2007a).

In August 2008, ALB was found in Worcester County, Massachusetts and 

in July 2010, six ALB-infested trees were discovered in Suffolk County in 

Massachusetts. ALB was discovered in Clermont County, Ohio in June 

2011.

In response to the introduction of ALB in these areas of the United States, 

APHIS implemented an adaptive management eradication program.

Currently, the ALB eradication program in the United States uses—

x visual surveys from the ground or aerial surveys by tree climbers or 

bucket trucks,

x quarantine areas (11⁄2 mile radius from infested trees) to restrict 

movement of regulated materials,

x application of a preventative/protective systemic insecticide to uninfested trees,

x removal of infested and high-risk host trees within the quarantine 

area, and

x public involvement, outreach, and education about ALB.

APHIS and its partners declared ALB eradicated from the following areas:

x Chicago, Illinois and Hudson County, New Jersey, in 2008

x Islip (Suffolk County, New York) in 2011

x Manhattan (New York County, New York) and Staten Island 

(Richmond County, New York) in 2013

10 I. Purpose of and Need for Action
2. Past Agency 

Outreach 

Efforts on 

ALB Issues

1. Prior EAs 

Published by 

the Agency 

and Results 

from Public 

Comments

x Middlesex and Union Counties, New Jersey in 2013

x Boston (Suffolk County, Massachusetts) in 2014

Active eradication programs are continuing in Queens, Brooklyn and

Suffolk and Nassau Counties, New York as well as in Worcester County, 

Massachusetts, and Clermont County, Ohio. 

B. Public Involvement 

APHIS has prepared 14 site-specific EAs regarding ALB eradication 

programs or research in New York, Illinois, New Jersey, Massachusetts, 

and Ohio, available for public comment since 1996 (appendix B).

APHIS provides many opportunities for public involvement and outreach 

regarding program activities in ALB-quarantined areas. As such, 

APHIS—

x provided media interviews for newspapers, and radio and television

outlets;

x issued press releases;

x conducted an annual advertising awareness campaign; 

x provided public service announcements on radio and television

stations;

x had a presence at industry shows, expos, and various outreach venues; 

x secured multiple airings on public television cable access stations 

across the United States of the “Lurking in the Trees,” ALB 

documentary, APHIS produced in conjunction with The Nature 

Conservancy, and made the documentary available on YouTube and 

iTunes; 

x posted information on social media including Facebook, Twitter, 

Pinterest and Flickr; 

x held public meetings as well as meetings with Federal and State

officials, town administrators, and other impacted groups and persons;

x provided informational materials and Web sites to the public,

including an online reporting function and the arrangement of a 

national-use ALB hotline telephone number.

I. Purpose of and Need for Action 11
Scoping is an open and early process to determine the issues to be 

addressed in an EIS, and to identify significant issues related to the 

proposed action covered in the EIS. As part of this process, APHIS sent 

out letters to all federally recognized tribal nations in the contiguous

United States, inviting them to participate in a conference call on July 10, 

2013. During this conference call, APHIS asked tribal nations to provide 

input on how ALB and its eradication could affect them, and also provided 

opportunity for them to ask questions about the ALB Eradication Program. 

Approximately 20 tribes participated in the conference call.

On August 16, 2013, APHIS published a notice of intent (NOI) in the FR

describing its intent to prepare a programmatic EIS for the ALB

Eradication Program (78 FR 50022–23, August 16, 2013). The public was 

invited to comment on the proposed EIS. 

In the NOI, APHIS identified the following resources requiring further 

examination, in this EIS, of the potential environmental effects:

x wildlife, including consideration of migratory bird species and changes 

in native wildlife habitat and populations;

x federally listed T&E species;

x soil, air, and water quality;

x forests and trees in residential areas, and impacts on property values;

x wood products industry and other economic impacts, including 

impacts on the firewood industry;

x human health and safety; and

x cultural and historic resources.

APHIS made available a press release regarding the NOI to media 

contacts in New York, Massachusetts, and Ohio, and through the APHIS 

Stakeholder Registry that contains almost 12,000 contacts, and in the ALB 

e-newsletter on August 29, 2013. In addition, APHIS conducted the 

following notification activities: 

x ALB project managers in New York, Massachusetts, and Ohio shared 

the NOI with their staff members, and any key contacts that may have 

an interest in an ALB EIS;

x Facebook post(s) on the ALB Facebook account located at 

https://www.facebook.com/asianlonghornbeetle;

3. Locations of 

Addressed 

Issues 

Raised 

by 

Stakeholders

12 I. Purpose of and Need for Action
x Twitter post(s) on the ALB Twitter account located at 

https://twitter.com/StopALB;

x posted on the AsianLonghornedBeetle.com homepage and each State 

page;

x posted on the APHIS ALB News and Information page;

x Massachusetts State Department of Agricultural Resources and 

Department of Conservation and Recreation partners were notified and 

asked to share the NOI;

x Ohio Department of Agriculture, Ohio Department of Natural 

Resources, Ohio State University, and Clermont County 

communication partners were notified and asked to share the NOI;

x notification to tribal contacts;

x notification to USDA Forest Service (FS) contacts;

x notification to U.S. Fish and Wildlife Service (FWS) contacts;

x notification to various partners and organizations, such as the Tree 

Care Industry Association, Nature Conservancy, Arbor Day 

Foundation, American Forest Foundation, various arboretums, Sierra 

Club, Society of American Foresters, and so on;

x APHIS–PPQ State Plant Health Directors in New York, Ohio, and 

Massachusetts shared the press release with FS, FWS, USDA–

Agricultural Research Service (ARS), USDA–Natural Resource 

Conservation Service (NRCS), State agriculture/forestry/natural 

resource/heritage, and industry contacts.

Although the comment period was to end on September 16, 2013, APHIS 

extended it to September 30, 2013. APHIS received 27 comment letters 

during the 45-day scoping period. All comments were fully considered by 

APHIS in the planning of this EIS. Issues and concerns identified by the 

public and tribal contacts included: 

x impacts from heavy equipment use and other property damage from 

program activities;

x impacts to soil and water quality;

x impacts to maple syrup producers;

I. Purpose of and Need for Action 13
x impacts to federally owned lands, such as national forests and national 

parks, State-owned nature preserves, natural heritage areas, and other 

high-value forest landscapes;

x use of adaptive management as new studies or best management 

practices (BMPs) are identified;

x insecticide pollution;

x impacts to T&E species, migratory birds, and their habitats;

x potential for ALB infestations through imported wood products;

x biological control of ALB;

x consideration of the Coastal Zone Management Act (CZMA) of 1972;

x potential for yard waste and brush to spread ALB in the United States;

x risk of ALB to all of North America if ALB is allowed to spread; and

x replacement of removed trees.

Many comments did not raise specific issues for analysis in this EIS;

however, opinions were provided for or against the selection of certain 

program control methods. 

APHIS and its cooperators recognize the public’s concern about the 

potential impacts of ALB and program activities on human health, 

biological resources, and the physical environment. These concerns will 

be addressed as part of this EIS and will be made available for further 

public input. 

C. Decision Framework

In the earliest EAs for ALB eradications in Illinois and New York, 

alternatives available to APHIS included quarantine only, suppression, and 

eradication. Although eradication was the preferred alternative, no 

chemical methods of control were available at the time. Only host tree 

removal followed by burning or chipping of removed wood material was 

available. After 2000, APHIS added a prophylactic treatment using the 

insecticide imidacloprid as an option to the ALB Eradication Program 

after tests proved it effective in protecting trees from ALB under certain 

conditions. However, imidacloprid treatments do not ensure complete 

control of ALB within a tree due to variability in treatments, weather 

14 I. Purpose of and Need for Action
1. No

Action

2. Removal of 

Infested Trees

4. Insecticide 

Treatment

conditions, and tree health, all of which can result in uneven distribution

of imidacloprid within a tree.

In the most recent EA prepared for Clermont County, Ohio, in May 2013 

(APHIS, 2013b), APHIS analyzed four alternatives: (1) no action by 

APHIS; (2) removal of infested trees and high-risk host trees up to 1⁄2 mile 

from infested trees (full host removal); (3) removal of infested trees and

imidacloprid treatment of high-risk host trees up to 1⁄2 mile from infested

trees; and (4) infested host removal and combination of removal or

imidacloprid treatment of high-risk hosts (preferred alternative). 

Alternatives 2 through 4 were eradication program options. 

Listed below are five alternatives for further examination in this EIS.

(Chapter 2 describes the alternatives in greater detail.)

Under the no action alternative, APHIS would not undertake eradication 

efforts. However, APHIS would continue to implement quarantine 

restrictions in the event of a confirmed ALB detection. This alternative 

represents the baseline against which a proposed action may be compared.

Under this alternative, APHIS would implement quarantine restrictions,

and would only remove trees infested with ALB. High-risk host trees 

would not be removed or treated.

Under this alternative, APHIS would implement quarantine restrictions, 

remove infested trees, and would remove high-risk host trees up to 1⁄2 mile 

from infested trees.

Under this alternative, APHIS would implement quarantine restrictions, 

remove infested trees, and treat high-risk host trees with an insecticide up 

to 1⁄2 mile from infested trees.

Under this alternative, APHIS would implement quarantine restrictions, 

would remove infested trees, and would use a combination of removal and

insecticide treatments of high-risk host trees (preferred alternative).

APHIS will not implement site-specific eradication projects as a direct 

result of the decision that will follow this EIS. Rather, APHIS will 

conduct site-specific EAs before the agency decides to implement any 

treatment project. EAs will address unique local issues, beyond the scope 

of this document, for site-specific management projects for ALB. Sitespecific EAs are more detailed and precise as to geographical locations

and strategies appropriate for the type of outbreak.

The decision on this EIS will serve as the primary guide for management 

of ALB in the contiguous United States. Treatments and strategies 

5. Integrated 

Approach

(Preferred

Alternative)

3. Full Host 

Removal

I. Purpose of and Need for Action 15
allowed by prior EA decisions will continue to be available for use. The 

decision whether to plan and implement an ALB project in the United 

States will occur on a case-by-case basis by APHIS.

D. Scope of this Document and NEPA Requirements

This EIS concerns only the APHIS ALB Eradication Program carried out 

by APHIS, directly or in conjunction with others (States, other Federal 

agencies, and tribal governments). The information and analysis 

contained in this EIS can be incorporated by reference into EAs and any 

other environmental documents prepared for ALB eradication projects, in 

accordance with NEPA. Some ALB-related activities, such as WPM 

importation regulations, inspection of WPM, and other ALB-regulated 

articles at the point of entry in the United States, and research and methods 

development activities are outside the scope of this document and were 

not examined. (For more information regarding environmental impacts of 

importation of WPM, see the APHIS EIS for Importation of WPM 

(APHIS, 2003), and the 2007 supplemental EIS (APHIS, 2007b)).

E. Consultations

Section 7 of the Endangered Species Act (ESA) and its implementing 

regulations require Federal agencies to ensure their actions are not likely

to jeopardize the continued existence of T&E species, or result in the

destruction or adverse modification of critical habitat. If necessary, 

APHIS conducts Section 7 consultation with the FWS and National 

Marine Fisheries Service (NMFS) on a site-specific basis for ALB 

eradication activities. 

APHIS considers whether critical habitat or listed species are present in 

the program area. If none are present, no Section 7 consultation is 

required. For the ALB Eradication Program in Worcester County, 

Massachusetts, APHIS consulted informally with FWS on a threatened 

plant, the small whorled pogonia (Isotria medeoloides), in 2008. In 2011, 

APHIS consulted informally with FWS on the impact of the ALB 

Eradication Program on the small whorled pogonia and piping plover 

(Charadrius melodus) in Norfolk and Suffolk Counties in Massachusetts. 

In June, 2011, APHIS first contacted FWS in Columbus, Ohio for 

technical assistance regarding impacts to federally listed species in 

Clermont County, Ohio. Seven endangered species (Indiana bat, Myotis 

sodalis; running buffalo clover, Trifolium stoloniferum; fanshell,

Cyprogenia stegaria; rayed bean, Villosa fabalis; snuffbox, Epioblasma 

triquetra; pink mucket pearlymussel, Lampsilis abrupta; and sheepnose, 

Plethobasus cyphyus) occur in Clermont County. 

16 I. Purpose of and Need for Action
Since that time, APHIS submitted biological assessments and consulted 

with FWS on those species, receiving concurrence with “may affect, not 

likely to adversely affect” determinations, with the implementation of 

protection measures. In addition, FWS personnel have made site visits to 

the infested area, and have provided Indiana bat training to APHIS and the 

Ohio Department of Agriculture personnel. In addition, APHIS conducted

surveys for Indiana bats in the Clermont County eradication work zones 

and reported those findings to FWS. Most recently, APHIS entered into a 

formal consultation with FWS on the Indiana bat (receiving a biological 

opinion dated June 4, 2014) and a conference on the northern long-eared 

bat (Myotis septentrionalis), a species proposed for listing as endangered

(receiving a conference opinion dated July 3, 2014). In the near future, 

APHIS has initiated a conference for the northern long-eared bat in New 

York and Massachusetts. 

APHIS will conduct ESA Section 7 consultations with the appropriate 

agency, as necessary, for any eradication programs if ALB is detected in 

new locations in the United States. Consultation with FWS, and NMFS, if 

necessary, at the local level will ensure that ALB eradication actions will 

not jeopardize the continued existence of a listed species or adversely 

modify critical habitat in the program area. APHIS will ensure the 

implementation of any protection measures for T&E species or critical 

habitat that result from such consultations. In addition, APHIS will ensure 

that site-specific consultations will be done, as necessary, under the 

National Historic Preservation Act, Migratory Bird Treaty Act, Bald and 

Golden Eagle Protection Act, and any other laws, regulations, Executive 

orders, and agency policies that apply to site-specific projects. 

I. Purpose of and Need for Action 17
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18 I. Purpose of and Need for Action
II. Alternatives 

This EIS analyzes the potential environmental consequences associated 

with the alternative options to eradicate ALB from areas in the contiguous 

United States where the insect establishes. The purpose of the alternatives 

is to describe the reasonable strategies the agency could take to achieve its 

goal. 

APHIS conducts survey activities and imposes Federal quarantines, 

according to the agency’s authority under the Plant Protection Act. 

Survey and quarantine are part of each alternative proposed, and are not 

unique to any one alternative. Therefore, descriptions for these two 

activities are independent from the descriptions for each alternative.

A. Quarantine

Federal quarantine authority for ALB includes 7 CFR § 301.51 for

eradication programs, 7 CFR § 319.40 for solid wood packing material,

and 7 CFR § 330 for plant pests. Under these regulations, APHIS 

establishes quarantines and regulates international and interstate 

movement of regulated plant host material, also referred to as regulated 

articles. APHIS cannot regulate intrastate movement without the State 

Plant Regulatory Agency first establishing an intrastate quarantine. 

Intrastate quarantine facilitates regulatory activities within a geographical 

area less than an entire State.

APHIS and State plant regulatory agencies establish quarantine boundaries 

1.5 miles from a tree with ALB-exit holes, and 0.5 miles from a tree with 

egg sites only.

Under quarantine, APHIS restricts the movement of articles, known as 

regulated articles, which present a risk of spreading ALB interstate from 

the quarantine area. The regulated articles listed under the quarantine 

7 CFR § 301.51, as published in 2013, include the beetle and all its life 

stages; firewood (all hardwood species, not restricted to ALB-host trees); 

green lumber, and other living, dead, cut, or fallen material, including 

nursery stock, logs, stumps, roots, branches, and debris from ALB-host

trees of 1⁄2 inch or more in diameter. 

As of December 2014, 13 genera of trees in the United States are regulated 

hosts for ALB, and are considered high-risk hosts because of ALB’s 

preference for feeding and completing its life cycle on these genera: Acer 

spp. (maple and box elder), Aesculus spp. (horse chestnut and buckeye),

Albizia spp. (mimosa), Betula spp. (birch), Celtis spp. (hackberry),

Cercidiphyllum spp. (katsura tree), Fraxinus spp. (ash), Koelreuteria spp. 

(golden rain tree), Platanus spp. (sycamore and London planetree), 

II. Alternatives 19
Populus spp. (poplar), Salix spp. (willow), Sorbus spp. (mountain ash), 

and Ulmus spp. (elm). ALB can complete its life cycle in these materials, 

and transport of these materials could spread ALB to non-infested areas. 

APHIS plans to remove the genus Celtis from the list of regulated hosts 

based on evidence that ALB is unable to complete its life cycle on species 

within this genus. (Appendix C provides additional information and 

references on the list of regulated host trees of ALB.)

Regulated articles originating from within the quarantine area may move 

outside the quarantine area if accompanied by a certificate or limited 

permit, unless the USDA moves the articles for scientific or research 

purposes. Issuance of a certificate or permit verifies that the host material 

underwent inspection by an APHIS-approved inspector, and is free of 

ALB. At this time APHIS has no approved regulatory treatments, 

(treatments applied to ALB-regulated articles), that would allow for the 

interstate movement of regulated articles, except for heat treatment for 

firewood. The quarantine does not limit the natural spread of ALB. (A

full description of the quarantine is found in 7 CFR 301.51.)

Removal of an area under quarantine occurs upon declaration that the area 

is free of ALB. APHIS makes this declaration when the final survey finds 

no ALB infestations after control activities, secondary surveys, and a 

minimum of 4 years has passed since the last evidence of ALB in an area.

The basis of the minimum 4-year survey interval is the beetle’s life cycle 

length (1 to 2 years) and the minimum length of time for the beetle’s 

population to grow to detectable levels should the beetle still be present.

To declare eradication, a final round of negative survey is needed at some 

time after surveys conducted as part of delimitation and control measures 

have failed to find ALB in the area. The final time interval selected would 

depend on the size/area of the original infestation, the prevalence of 2-year 

ALB life cycles (if any) in the program area, and other programmatic and 

logistic factors. (Maps of ALB quarantine areas in the United States are 

available from the Plant Health link at 

http://www.aphis.usda.gov/wps/portal/aphis/home)

B. Survey

ALB Program inspectors conduct surveys to (1) determine the scope of the 

infestation; (2) establish the quarantine area; (3) determine that ALB has 

not spread outside of the established quarantine area and, if it has, to 

expand the quarantine area; and (4) determine when to release an area 

from quarantine. The types of surveys conducted in an area depend on the 

scope of the infestation, and the circumstances surrounding the infestation. 

Below is a general description of surveys; however, there is flexibility in 

the survey protocols. For example, the number of times ALB Program 

20 II. Alternatives
inspectors survey an area depends on forest and host composition, the 

degree of infestation, and the time it takes between survey cycles. The 

control strategy employed in an area (e.g., removal and/or treatment of all 

host trees in an area) will affect the number of survey cycles. As new 

biological information becomes available on ALB and survey strategies 

evolve, APHIS expects the survey protocols for the ALB eradication 

program to change. Site-specific EAs for the ALB eradication program 

will indicate changes to the following survey description.

The discovery of ALB triggers a Level 1 survey, also known as core 

survey, to determine the scope of the infestation. Before the survey 

begins, the APHIS National Identification Service confirms the suspect 

specimen as ALB through structural and/or genetic identification. Once 

confirmed, Program inspectors survey neighboring host trees for 

oviposition (egg) sites and exit holes that may indicate an ALB infestation. 

During the Level 1 survey, ALB Program inspectors visually look for 

signs of infestation on every regulated host tree in a circular radius around 

the infestation, until they fail to find ALB within approximately a 1⁄2-mile 

radius of infested trees. Signs of infestation on host trees include exit 

holes, oviposition sites, frass, tunneling (formed as larvae and bore into 

the tree), and sap flow from damaged sites. Inspectors search for signs 

using binoculars from the ground, and may conduct aerial tree inspections 

through trained professionals using bucket trucks to peer into trees from 

above, and by trained tree climbers to search for signs of an infestation 

within tree canopies. Interest groups and organizations voluntarily assist 

inspectors by searching trees from the ground using binoculars. Use of 

tree climbers is the most effective method of detecting signs of ALB; 

however, this is also a slower and more costly method (Hu et al., 2009).

Currently, no method of visual survey, including visual surveys for ALB, 

is completely effective in pest detection (Bulman et al., 1999).

If inspectors find additional infestations, APHIS extends the 1⁄2-mile radius 

from the outermost find. APHIS bases the 1⁄2-mile radius on studies 

published in the scientific literature, as well as unpublished data on ALB’s 

natural spread potential (Smith et al., 2001; Smith et al., 2004; Williams 

et al., 2004; Bancroft and Smith, 2005).

Survey areas may include residential, commercial, or public land; access 

to these properties is necessary for the Program. The Program removes 

trees infested with ALB.

The Level 2 survey is a safeguard to ensure that ALB is not spreading 

beyond the 1⁄2-mile radius around infested host trees established during the 

Level 1 survey. During the Level 2 survey, also known as a buffer survey, 

inspectors survey host trees within a minimum of 1 mile beyond the 

1. Level 1 

Survey 

(Core Survey)

2. Level 2 

Survey 

(Buffer)

II. Alternatives 21
survey boundary set during the Level 1 survey. This results in 

approximately a 11⁄2-mile radius from the point of infestation for trees with 

less than 100 exit holes. Level 2 Survey areas should be expanded to a 

minimum of 2.5 miles from areas that are or were centers of high 

populations, as denoted by the presence of a cluster of trees with many 

exit holes or one or more trees with >100 exit holes. This boundary 

expansion only applies to survey and not regulatory boundaries (the two 

can differ). APHIS bases the additional 2.5 mile boundary expansion on 

the high infestation or population level which indicates ALB has likely 

been in the area for some time as well as the beetle’s behavior to move 

away from its hatch tree when ALB populations are high (Williams et al., 

2004).

During the Level 2 survey, inspectors focus on maple trees (Acer spp.) 

where they are present. Additional preferred hosts (Aesculus, Betula,

Populus, Salix, and Ulmus) are surveyed when maples are not present or 

are within 100 yards of the last inspected preferred host tree. Sweet birch 

(Betula lenta) and Japanese maple (Acer palmatum) are not considered 

preferred hosts. The Program may adjust the survey radius upon 

discovery of additional infested trees.

Similar to the Level 1 survey, inspectors complete the survey using 

binoculars from the ground, and may use bucket trucks and/or tree 

climbers to perform aerial surveys.

Depending upon terrain or geographic layout (e.g., urban/suburban streets 

versus a forested area), inspectors use differing techniques to move 

quickly through an area to determine the extent of the infestation and 

determine the quarantine boundary. For example, in an urban setting, 

inspectors may skip to the next street or block; in wooded locations, 

inspectors may use a grid pattern. The intention of this survey is to 

quickly understand the general area of infestation, and determine the type 

of response needed in terms of resources and quarantine enactment. 

The ALB Program may conduct a Level 3 survey, also called a high-risk 

site survey. This survey extends beyond established survey boundaries to 

inspect high-risk sites.

The Program conducts high-risk site surveys (Level 3) to identify and 

inspect high-risk locations where potentially infested host material may 

have been transported, stored, processed, or sold. Site inspections 

primarily focus on maples when they are present. High-risk sites include, 

but are not limited to:

x Landscape and nursery businesses

x Tree and lawn care companies

3. Level 3 

Survey 

(High-Risk 

Survey)

22 II. Alternatives
x Firewood producers and transporters

x State and local parks/forestry departments

x Local utility and sanitation services

x Parks and campsites

x Landfills and disposal sites

x Import facilities that receive or have received high-risk cargo from 

known source countries

x Stone dealers or stone cutting facilities such as monument/headstone 

companies near infestations

After APHIS completes the first survey cycle and removes or treats 

infested trees and trees with a high risk of becoming infested, inspectors 

conduct secondary surveys, which is a repeat of survey Levels 1 and 2. 

Secondary surveys may take place more than once in an area, depending 

on the amount of time that has passed since the last survey cycle. 

The amount of time between surveys can influence the survey frequency

due to the understanding that ALB infestations develop over time and 

signs of infestation become more readily detectable.

Secondary surveys continue until a final cycle confirms there are no 

infested trees. Four years is the minimum amount of time between an 

initial detection and a final survey cycle is completed. The Program may 

conduct an interim survey should more than 4 years lapse since the first 

survey cycle occurred and the Program has yet to conduct a final round of 

negative survey. This would provide an extra level of assurance that a 

population no longer remains and could limit the scope and expense of the 

ensuing program should detection of ALB occur. 

C. Alternatives Evaluated in this EIS

APHIS is considering five alternative options, four of which are 

eradication program options. The five alternative options derive from 

scientific research published in peer-reviewed scientific journals, and 

experience in the eradication programs in Illinois, New York, New Jersey, 

Ohio, and Massachusetts. These alternatives are not unique to this EIS; 

other EAs prepared by APHIS include one or more of these alternatives 

(appendix B). Briefly, the five alternative options considered in this EIS 

include No Action, Removal of Infested Trees, Full Host Removal, 

Insecticide Treatment, and An Integrated Approach (see table 2–1).

Adaptive Management

This EIS proposes the use of specific chemical treatments as part of the 

ALB Eradication Program under the various alternatives with the 

exception of the no action alternative. Herbicides are proposed for use in

4. Secondary 

Survey

II. Alternatives 23
Table 2–1. Overview of Alternatives in this EIS.

Methods Alternatives*

1 –

No Action

2 –

Removal of 

Infested 

Trees

3 –

Full Host 

Removal

4 –

Insecticide 

Treatment

5 –

Integrated 

Approach

Remove and chip or 

incinerate infested 

trees 

X XX X

Remove and 

chip/incinerate highrisk host trees within a 

1⁄2-mile radius of 

infested trees

X X

Grind stumps of cut 

trees X XX X

Treat stumps and 

sprouts of cut trees 

with herbicide

X XX X

Allow stumps of host 

trees to regenerate X X

Site restoration X X X X

Imidicloprid treatment 

of high-risk host trees 

within a 1⁄2-mile radius 

of infested trees (only 

with landowner’s 

permission)

X X

* Imposing Federal quarantines and conducting surveys to determine the extent of ALB infestation 

are part of all the alternatives.

Adaptive Management

This EIS proposes the use of specific chemical treatments as part of the 

ALB Eradication Program under the various alternatives with the 

exception of the no action alternative. Herbicides are proposed for use in 

all the alternatives with the exception of the no action alternative, while 

insecticide use is proposed under alternatives 4 and 5. The Program could 

add other treatment(s) that may become available in the future to currently 

approved treatments for managing ALB, referred to as adaptive 

management. A new treatment would be available for use upon the 

agencies’ finding that the treatment is registered by EPA for use on ALB, 

and poses no greater risks to human health and nontarget organisms than 

are disclosed in this EIS for the currently approved treatments. The 

24 II. Alternatives
protocol for making the necessary finding that a treatment is authorized by 

adaptive management is as follows:

1. Conduct a human health and ecological risk assessment (HHERA). 

In this risk assessment, review scientific studies for toxicological and 

environmental fate information relevant to effects on human health 

and nontarget organisms. Use this information to estimate the risk to 

human health and nontarget organisms. Include these four elements 

in the HHERA: (a) hazard evaluation, (b) exposure assessment, (c) 

dose response assessment, and (d) risk characterization. The 

HHERA will do the following: 

x Identify potential use patterns, including formulation, application 

methods, application rate, and anticipated frequency of 

application. 

x Review hazards relevant to the human health risk assessment, 

including systemic and reproductive effects, skin and eye 

irritation, dermal absorption, allergic hypersensitivity, 

carcinogenicity, neurotoxicity, immunotoxicity, and endocrine 

disruption. 

x Estimate exposure of workers applying the chemical. 

x Estimate exposure to members of the public. 

x Characterize environmental fate and transport, including drift, 

leaching to ground water, and runoff to surface streams and 

ponds. 

x Review available ecotoxicity data, including hazards to 

mammals, birds, reptiles, amphibians, fish, and aquatic 

invertebrates. 

x Estimate exposure of terrestrial and aquatic wildlife species. 

x Characterize risk to human health and wildlife. 

2. Conduct a risk comparison of the human health and ecological risks 

of a new treatment with the risks identified for the currently 

authorized treatments. This risk comparison will evaluate 

quantitative expressions of risk (such as hazard quotients), and 

qualitative expressions of risk that put the overall risk 

characterizations into perspective. Qualitative factors include scope, 

severity, and intensity of potential effects, as well as temporal 

relationships, such as reversibility and recovery. 

3. If the risks posed by a new treatment fall within the range of risks 

posed by the currently approved treatments, publish a notice in the 

FR of the agencies’ preliminary findings that the treatment meets the 

requirements of this alternative. The notice must provide a 30-day 

public review and comment period, and must advise the public that 

the HHERA and the risk comparison are available upon request.

II. Alternatives 25
4. If consideration of public comment leads to the conclusion that the 

preliminary finding is correct, publish a notice in the FR that the 

treatment meets the requirements of this alternative and, therefore, is 

authorized by this alternative for use in the APHIS ALB 

management program. APHIS will make available to anyone, upon 

request, a copy of the comments received and the agencies’ 

responses.

The decision to be made as a result of this EIS will be programmatic. 

Decisions to use specific treatments in projects (including new treatments 

authorized under the protocol in this alternative) will be made after sitespecific environmental analyses are conducted and documented, in 

accordance with agency NEPA implementing procedures.

Under this alternative, activities for ALB would not involve APHIS. 

Other Federal or non-Federal entities may apply control measures; 

however, APHIS would not manage or fund these measures. Under this 

alternative, APHIS could conduct surveys to determine the extent of an 

infestation, and implement quarantine restrictions where ALB infestations 

occur. 

This alternative represents the baseline against which to compare a 

proposed action. This alternative is not an eradication program.

This alternative would consist of the following:

x Implementing or maintaining the quarantine and 

expanding or contracting the quarantine area 

based on ALB’s distribution, as determined 

through survey

All of the 

alternatives in this 

EIS include survey 

and quarantine

x Removing all infested trees

x Chipping or incineration of cut trees

x Grinding or herbicide treatment of stumps

x Restoring the tree-removal site

APHIS and its cooperators, which includes State or forestry officials, 

contractors, and other entities collaborating with APHIS (referred to 

collectively as the Program), would remove trees infested with ALB. 

APHIS declares a tree infested if program inspectors find at least one 

oviposition site or exit hole characteristic of the shape and size as those 

formed by ALB, regardless of being able to determine the viability of 

ALB inside the tree. APHIS uses this criterion after official confirmation 

through structural or genetic identification that ALB is in the area. APHIS 

will notify in writing by direct mailing, or in person, any landowner who 

will have infested trees removed from their property.

1. No 

Action

2. Removal of 

Infested 

Trees

26 II. Alternatives
After tree removal, the Program destroys cut trees through incineration or 

by passing the trees through a chipper to destroy the ALB life stages 

(larvae, pupae, and adults) that may be within those trees, thus eliminating 

potential adult beetle emergence, dispersal, and mating. Eggs may be able 

to survive the chipping process due to their small size; however, after 

hatching, larvae develop by feeding on the thin layer of generative tissue 

lying between the bark and the wood of a stem (cambium)—chipping 

makes this area unsuitable for the development of larvae (Wang et al., 

2000). Chipping of trees to a size of less than 1 inch, in at least two 

dimensions, removes the risk of ALB (Wang et al., 2000). Chips of this 

size are no longer subject to Federal or State regulations. The Program 

chips trees in place or takes the tree to an approved establishment for 

chipping. 

ALB can reinfest stumps, above-ground roots, and any shoots that may 

grow from these tree parts, so it can be beneficial to remove and grind 

stumps from infested trees. APHIS may use herbicides when there are 

limitations to physically removing stumps. For example, the area is 

inaccessible to equipment used for stump removal and grinding, or the 

area is sensitive to erosion or compaction. The Program uses the herbicide 

triclopyr by spraying or painting the root collar area, the sides of the 

stump, and the outer portion of the cut surface, including the cambium, 

until thoroughly wet but not to runoff. Foliar applications of triclopyr 

mixed with two other herbicides, imazapyr and metsulfuron-methyl, are

applied to sprouting foliage from stumps that remain after tree removal to 

prevent regrowth. APHIS would apply adaptive management as described 

earlier in this section of the EIS. In some locations, APHIS may leave 

stumps and allow regrowth, particularly in areas prone to soil erosion or 

sensitive wildlife habitats. 

After tree removal from yards and landscaped settings, the Program 

restores the area through grading and planting groundcover consistent with

the area where the removals took place. This reduces the opportunity for 

invasive weeds to establish, and provides a groundcover that will help 

hold the soil in place. However, in woodlot settings a seed bank already 

exists in the soil that would result in rapid vegetation growth, therefore, 

planting groundcover may be unnecessary. 

APHIS will remove an area from quarantine as described previously.

II. Alternatives 27
The Program, under this alternative, would consist of the following:

x Implementing or maintaining the quarantine 

and expanding or contracting the quarantine 

area based on ALB’s distribution as determined 

through survey

All of the 

alternatives in this 

EIS include survey 

and quarantine 

x Removing infested trees As described in 

Alternative 2—

Removal of Infested 

Trees

x Chipping or incineration of cut trees

x Grinding or herbicide treatment of stumps 

x Restoring the tree-removal site

x Removing high-risk host trees within a 1⁄2-mile 

radius of an infested tree(s)

Under this alternative, the Program would conduct pest surveys, 

implement quarantine restrictions, and remove infested host trees, as 

described in alternative 2. Signs of low infestation levels may not be

readily apparent on high-risk host trees, and can remain unnoticed by 

visual survey. Consequently, due to their proximity to known infested 

trees, there are chances that nearby high-risk host trees have undetected 

infestations or are at risk of infestation. Therefore, the Program would 

also remove high-risk host trees within a 1⁄2-mile radius of infested host 

trees. 

The basis for removing trees within the 1⁄2-mile radius is on the dispersal 

behavior of ALB, and the level of effectiveness of visual survey on lightly 

infested trees. In a study in Illinois, 99 percent of trees with ALB egglaying sites were within 1⁄4 mile of a tree from which adult ALB exited 

(Sawyer, 2006). APHIS may add an additional 1⁄4 mile to the radius for 

host tree removal around infested trees to capture beetles that may have 

spread further (Sawyer, 2006). APHIS will notify the landowner prior to 

the removal of infested and high-risk host trees. If the landowner refuses 

to allow removal of high-risk host trees, the Program would not remove 

them, but would continue to survey and, if ALB infests those trees, APHIS 

would remove the trees after notifying the landowner. 

The cutting and removal of trees is the same as described in alterative 2.

The Program would focus tree removal efforts first by removing infested 

trees to eliminate the population of ALB, and then remove high-risk host 

trees located within the 1⁄2-mile radius of infested trees. However, tree 

removal may not always occur in this order. For example, it is more time 

and cost effective to finish removing all the trees in an area before 

relocating equipment to a new staging area. 

3. Full Host 

Removal

28 II. Alternatives
APHIS removes and grinds or treats stumps and roots of felled trees with 

herbicides, as described in alternative 2. However, in some cases, such as 

woodlots, stumps may not be ground or treated with herbicides to allow 

for regrowth of host trees. APHIS would apply adaptive management, as 

described earlier in this section of the EIS.

APHIS will remove an area from quarantine as described previously.

The Program, under this alternative, would consist of the following: 

x Implementing or maintaining the quarantine and 

expanding or contracting the quarantine area 

based on ALB’s distribution, as determined 

through survey

All of the 

alternatives in this 

EIS include 

survey and 

quarantine

x Removing infested trees As described in 

Alternative 2—

Removal of 

Infested Trees

x Chipping or incineration of cut trees

x Grinding or herbicide treatment of stumps 

x Restoring the tree-removal site

x Treating high-risk host trees within a 1⁄2-mile 

radius of infested trees with an approved 

insecticide, following product label requirements.

Under this alternative, APHIS would remove only infested trees, as 

described in Alternative 2, Removal of Infested Trees. Due to their 

proximity to known infested trees, there is a chance nearby host trees are 

at risk of infestation. APHIS would treat high-risk host trees, located up

to 1⁄2 mile of an infested tree, with the insecticide imidacloprid, but only 

with permission from the landowner. APHIS uses the insecticide to 

protect trees from ALB infestation but does not use the insecticide to treat 

infested trees. If the landowner does not allow imidacloprid treatment of 

trees on their property, the Program will not treat them; however, survey 

efforts would continue. Once trees become infested with ALB, the 

Program would remove them following notification of the landowner. 

Application of imidacloprid is through trunk or soil injection, according to 

product label requirements. The Program makes insecticide treatments in 

the spring, early summer or fall, prior to and during the adult emergence 

period, in order to allow the insecticide to distribute throughout the tree 

and, therefore, be most effective. 

The rate of imidacloprid used depends on the application method, as well 

as the size of the tree to be treated. Pesticide applicators adhere to the 

requirements on the product label. For trunk injections, applicators drill 

4. Insecticide

Treatment

II. Alternatives 29
holes around the trunk, 2 to 6 inches above the soil-wood line, and inject 

imidacloprid. It takes 1 to 3 weeks for the insecticide to distribute 

throughout the tree, depending on the size and condition of the tree and 

weather conditions. Trunk injections are the most common application 

used by the Program. For soil injection, applicators inject imidacloprid at 

a minimum of four injection sites, spaced evenly around the base of the 

tree. Application occurs under the soil around the base of the tree, 

normally no more than 12 inches from the base. No material may puddle 

or run offsite. It may take up to 3 months before plant tissues absorb 

sufficient quantities of imidacloprid, depending on the size and condition 

of the tree and weather conditions. 

For maximum efficacy, APHIS repeats insecticide applications once a 

year over a consecutive 3-year period to ensure that the concentration of 

the insecticide within the treated tree is at an adequate level to protect the 

tree from ALB infestation. Imidacloprid treatments do not ensure 

complete control of ALB within a tree due to variability in treatments, 

weather conditions, and tree health, all of which can result in uneven 

distribution of imidacloprid within a tree. APHIS would apply adaptive 

management as described earlier in the EIS.

APHIS will remove an area from quarantine as described previously.

An integrated approach would consist of the following: 

x Implementing or maintaining the quarantine 

restrictions, and expanding or contracting the 

quarantine area based on ALB’s distribution as 

determined through pest surveys

All of the 

alternatives in this 

EIS include survey 

and quarantine

x Removing infested trees

x Chipping or incineration of cut trees

x Grinding or herbicide treatment of stumps

x Restoring the tree-removal site

As described in 

Alternative 2—

Removal of Infested 

Trees

x Removing high-risk host trees within a 1⁄2-mile 

radius of an infested tree(s)

As described in 

Alternative 3—

Full Host Removal

x Removing or treating with an approved 

insecticide, according to label requirements, 

high-risk host trees up to 1⁄2 mile-radius from 

infested tree

As described in 

Alternative 4—

Insecticide 

Treatment

5. An 

Integrated 

Approach 

(Preferred 

Alternative)

30 II. Alternatives
For this alternative, the Program will remove infested trees and treat with 

imidacloprid, or remove high-risk host trees within a 1⁄2-mile radius of 

infested trees. APHIS will base the determination to treat or remove 

high-risk host trees on levels of infestation in the area, host tree density 

and distribution, potential environmental impacts, and logistical resources. 

This alternative provides the most flexibility in selecting an appropriate 

control method for a location. It is also the most cost effective method 

because this alternative does not prescribe that all high-risk host trees must 

be treated or removed; rather, it allows flexibility in focusing treatments 

on the host trees most preferred by ALB (i.e., Acer, etc.), or certain 

locations that would be higher risk than others. 

As with the other action alternatives, APHIS would remove or treat with 

imidacloprid the high-risk host trees located up to 1⁄2 mile of an infested 

tree only with permission from the landowner. If the landowner does not 

allow removal or imidacloprid treatment of trees on their property, the 

Program will not remove or treat them but will continue survey efforts. If 

trees become infested with ALB, the Program would remove them 

following notification of the landowner. 

APHIS would apply adaptive management as described earlier in this 

section of the EIS.

APHIS will remove an area from quarantine as described previously.

D. Alternatives Considered but Not Included in this 

EIS

APHIS evaluated other insecticide chemistries for their efficacy towards 

ALB (appendix B). Imidacloprid is currently the only effective, registered 

product available for use against ALB.

a. Biological Control

Biological control (biocontrol) is the means of reducing or mitigating pests

and pest effects with natural enemies. ALB causes damage within its 

native range despite the presence of associated natural enemies. Research 

on biocontrol methods for ALB are ongoing, however, none are available

for large-scale use. 

2. Other 

Integrated 

Pest 

Management/

Suppression 

Strategies

1. Use of Other

Chemical 

Control 

Agents

II. Alternatives 31
b. Sterile Insect Technique 

Sterile insect technique (SIT) involves breeding and releasing large 

populations of sterile male insects with the goal of outcompeting fertile 

males during mating with females. This leads to a reduction in the size of 

the population, and potential eradication of an insect population. Current 

SIT technology is not feasible based on the ALB life cycle.

c. Insect Pheromones 

Insect pheromones are naturally produced chemicals that can be used by 

insects to attract each other, and have been used in pest management for 

survey and suppression of target pests. The identification of insect 

pheromones specific to ALB is currently an ongoing area of research;

however, additional work is needed before it can be successfully 

implemented in the ALB Eradication Program.

d. Regulatory Treatments

APHIS has determined that it is necessary to add a treatment schedule for 

ALB in the Plant Protection and Quarantine Treatment Manual. A 

treatment evaluation document has been prepared that discusses the 

existing treatment schedule and explains why this change is necessary.

The document was made available to the public for review and comment 

until April 11, 2014. The public can access the “Notice of Availability of 

a Treatment Evaluation Document for Heat Treatment for Asian 

Longhorned Beetle” (Docket No. APHIS-2013-0094) online at 

http://www.regulations.gov/#!documentDetail;D=APHIS-2013-0094-

0002).

e. Additional Methods Development and Research

Additional methods development projects include looking at chip size and 

grinding techniques to deregulate host material, and assessing the use of 

pesticide treatments in the fall. Research continues with analysis to 

determine how fast the insect spreads on its own, evaluating the host trees 

the beetle attacks for preference and range, DNA analysis and behavioral 

experiments.

32 II. Alternatives
III. Affected Environment

This section presents a baseline description of the environmental resources 

that would be affected by implementation of the alternatives presented in 

chapter 2. Environmental resources include physical and biological 

resources, as well as the economic and social factors affecting people.

Because this is a programmatic EIS, the description of the affected 

environment contained in this chapter is, by necessity, general. The 

potentially affected environment in the United States is anywhere host 

trees susceptible for ALB infestation are found. Given the known 

distribution of ALB, the insect is probably capable of surviving anywhere 

in the United States where suitable host plants and climatic conditions are 

available. 

A. Affected Forest Communities

Forest trees grow either in pure stands comprised of a single species or in 

mixed stands. Tree density and type influence the sub-canopy plant 

species by altering the shade levels, soil composition, moisture levels, and 

other attributes. Forests fall on public or private lands, and occur on 

uplands, riparian areas (the interface between terrestrial and aquatic 

ecosystems), wetlands, and coastal environments. 

Indicators of forest conditions include tree mortality and growth rates, 

degree of insect and pathogen damage, and species composition in the 

understory and canopy. Tree mortality from ALB can affect the 

composition of forest communities. As ALB and other introduced insects 

and pathogens spread, they add stress to forest communities. Other forest 

stressors, including reduced water and air quality, and geological and soil 

disturbance often result from human activity. As the proximity and size of 

human populations increase, the forest canopy coverage and biological 

diversity decreases, while fragmentation and ecological disturbance 

increases.

In the United States, 13 tree genera are regulated hosts for ALB: Acer

(maple and box elder), Aesculus (horse chestnut and buckeye), Salix

(willow), Ulmus (elm), Betula (birch), Albizia (mimosa), Celtis

(hackberry), Cercidiphyllum (katsura tree), Fraxinus (ash), Koelreuteria

(golden raintree), Platanus (sycamore and London planetree), Sorbus

(mountain ash), and Populus (poplar) (APHIS, 2009), 7 CFR 301.51–2). 

APHIS expects to remove Celtis from the list of regulated host trees based 

on observation that this is not a host tree. The degree of susceptibility of a 

forest to ALB is dependent upon the composition of tree species, including 

the total density (basal area per acre) and proportion of an area covered by 

III. Affected Environment 33
susceptible stands. Within the United States, the distribution of host 

species is largely concentrated in the mid-Atlantic, New England, and 

Great Lakes regions (referred to as the Northeast Region by the FS (figure 

3–1), occupying a range of ecosystems including riparian and wetland 

areas. In the Northeast Region, forests (mostly privately owned) cover 

42 percent of the land base (Shifley et al., 2012). The composition of trees 

in the Northeast Region includes the maple-beech-birch forest-type group 

that accounts for 29 percent of the forest area; elm-ash-cottonwood for 

6 percent; and aspen-birch for 10 percent (Shifley et al., 2012).

Combined, these forest-type groups account for 45 percent of the forest 

area. In other regions of the United States, ALB-host species are found 

but make up a smaller component of the tree species growing in these 

forest areas (figure 3–1). However, many of these species are planted as 

ornamentals and urban shade trees elsewhere in the United States

(Peterson et al., 2004).

Figure 3–1. Forest areas potentially at risk to Asian longhorned beetle.

**This map does not include host genera planted in urban and suburban areas.

(Data source: (USGS, 2014))

34 III. Affected Environment
It is possible that other tree species could become confirmed hosts for 

ALB, which may increase the geographic scope of the environmental 

impacts. (See appendix C for an annotated list of ALB hosts.)

B. Affected Water Resources

Surface and ground waters within or near affected forest communities may 

be part of the affected environment. Surface waters include streams, 

lakes, wetlands, and reservoirs. Surface water seeps underground forming 

aquifers, also known as ground water. The combination of surface water 

and underlying ground water within an area that drains to a common 

outlet, (e.g., a waterway, wetland, reservoir, aquifer, or ocean) is a 

watershed. In the contiguous United States, there are 2,110 watersheds

that may contain ALB-host trees. Nationally, around 53 percent of the 

water supply originates on forestlands (Shifley et al., 2012). In the 

Northeast Region, 48 percent of the water supply originates on 

forestlands; in the South Region, 51 percent; in the Pacific Coast Region, 

72 percent; and the Interior West Region, 43 percent (Shifley et al., 2012).

American Heritage Rivers are rivers that represent natural, cultural, and 

historical resources and flow through forest ecosystems, including 

suburban and urban forests. Created by Executive Order 13061 

(September, 11, 1997), with selection criteria developed by the Council on 

Environmental Quality (CEQ), the EPA has designated 14 rivers in the 

contiguous United States as American Heritage Rivers. Examples include 

the Connecticut River, Cuyahoga River, Hudson River, Mississippi River, 

and the Potomac River.

The National Estuary Program is a network of voluntary community-based 

programs which safeguards the health of important coastal ecosystems 

across the country. The National Estuary Program, established under 

Section 320 of the 1987 Clean Water Act (CWA) amendments, calls for 

each national estuary program to develop and implement a comprehensive 

conservation and management plan that contains specific targeted actions 

designed to address water quality and habitat challenges in its estuarine 

watershed (EPA, 2013c). Twenty-seven national estuary programs are in 

place throughout the contiguous United States.

The Coastal Zone Management Act of 1972 (as amended), administered 

by the U.S. Department of Commerce, National Oceanic and Atmospheric 

Administration (NOAA), Office of Ocean and Coastal Resource 

Management (OCRM), provides for management of the nation's coastal 

resources, including the Great Lakes. Federal agencies are to cooperate 

with NOAA if their activities affect any land or water use, or natural 

resource of the coastal zone (16 U.S.C. § 1456, Section 307). Host trees

III. Affected Environment 35
of ALB occur in some coastal zones; ALB infestation and pursuant 

management activities can affect natural resources in these areas. 

Physical, biological, and chemical alterations to ecosystems through 

natural means or invasive species and human activity can affect water 

quality and quantity. Indicators of water quality include the flow rate, as 

well as water and sediment chemistry. 

Forested landscapes directly and indirectly affect water resources through 

a variety of mechanisms, including the stabilization of soil and prevention 

of sediment runoff; influence on the water cycle by controlling rainfall 

runoff, flooding, and uptake and evapotranspiration of water; and effects

on water temperature and understory plant growth by casting shade. 

Canopy gaps (reduced shade cover) can contribute to a decrease in soil 

moisture due to the increase in levels of light reaching the ground, as seen 

with the loss of hemlock trees to the hemlock wooly adelgid, an insect pest 

introduced in the United States (Orwig and Foster, 1998; Orwig et al., 

2008). Canopy gaps can also contribute to an increase in water 

temperature thereby affecting aquatic life, including plants, animals, and 

invertebrates (Kaushal et al., 2010). Reduced tree density and canopy 

gaps can affect forest undergrowth and soil stability, and can increase 

overland water flow, water yield, and runoff; however, the magnitude, 

timing, and duration of the response varies considerably among forest 

communities (Hornbeck et al., 1993; Wear and Greis, 2013). Increases in 

water yield coincide with the mobilization and leaching of nutrients in 

some forest communities (Hornbeck et al., 1993). Urban development and 

conversion of forested lands to agriculture are major contributors to 

reduced forest canopies and increases in water runoff, affecting the 

temperature and water chemistry of streams and water bodies (Wear and 

Greis, 2013).

The vegetation in riparian areas and wetlands contribute to water quality 

and quantity. A wetland is a land area saturated with water at a frequency 

and duration to support vegetation adapted for life in saturated soil 

conditions. Many of the tree species that are regulated hosts to ALB grow 

in riparian and wetland areas, including maple (Acer), elm (Ulmus), ash 

(Fraxinus), cottonwood (Populus), sycamore (Platanus), willow (Salix), 

and birch (Betula) (USGS, 1998; NHDES, 2008; NCFS, n.d.). Changes in 

tree cover and density in these aquatic habitats can have negative impacts 

on streambank stabilization, water temperature, sediment loading, 

hydrology, nutrient cycling, and contaminant removal (Wenger, 1999; Lee 

et al., 2004; Jones et al., 2006).

For example, maple trees are a critical component in soil nitrification in 

the Northeast United States, and their loss could affect nitrogen retention 

1. Water 

Quality

36 III. Affected Environment
and cycling in forested watersheds (Lovett and Rueth, 1999; Lovett and 

Mitchell, 2004). Nitrification is the oxidation of nitrogen-containing 

compounds into nitrate, which is an important component of the nitrogen 

cycle. A decrease in maple stands would lead to higher nitrogen retention 

in soils and reductions in nitrogen transport into aquatic systems. The 

alteration of nitrogen cycling, due to the loss of maples, would alter plant 

succession and diversity in terrestrial environments, as well as affect 

aquatic ecosystems that are dependent on higher nitrogen inputs.

Forested landscapes, including floodplains, wetlands, and riparian areas 

moderate flooding and filter sediments and pollutants (Dosskey et al., 

2010), protecting water quality. Alterations to the quality of these surface 

waters can impair the values they impart. Human communities rely on 

surface and ground water for drinking water, irrigation, and recreational 

activities. Waters in urban and agricultural areas tend to have an increased 

nutrient concentration and load. Excess nutrients mostly arise from

fertilizers, wastewater effluent, and industrial waste in urban areas; and 

animal waste, fertilizers, and chemicals in agricultural areas (Wear and 

Greis, 2013).

The Clean Water Act (CWA) provides a structure for regulating the 

discharge of pollutants into waters, and regulates quality standards for 

surface waters. Section 303(d) of the CWA requires States to develop lists 

of its impaired and threatened waters (stream/river segments, lakes) (EPA, 

2014c). Causes for impairment are numerous and include categories such 

as pathogens, metals, salinity, sediments, pesticides, trash, and other 

organic and inorganic compounds. Most States have one or more 

impaired waters, meaning that the water is not meeting one or more of its 

designated uses (EPA, 2014c). Assessments are not complete for all 

watersheds.

Soil quality impacts water quality and availability. A well-managed soil 

will have good porosity (space between soil particles), allowing it to be an 

efficient receiver of rainwater. Water that infiltrates the soil, in the 

absence of excessive nutrient or contaminant loads, is generally purified 

before entering ground water sources or returning to surface water bodies 

(Karlen et al., 1997). However, improperly managed or disturbed soil 

typically results in poor porosity, leading to surface water runoff carrying 

potential pollutants and soil particles with it. Soil enters surface waters as 

sediment, and can negatively affect water quality. Smaller particles (e.g., 

clay) stay in suspension contributing to water turbidity (Cook, 1990).

Riparian and floodplain habitats are especially sensitive to changes in

water quality (Doupé et al., 2010). By volume, sediment is the largest 

cause of impairment of rivers and streams across the United States 

(Cunningham et al., 2001; EPA, 2013b).

2. Interactions 

of Soils with 

Water Quality

III. Affected Environment 37
C. Affected Soil 

Soil types capable of supporting ALB-host trees are part of the affected 

environment. The physical, chemical, and biological characteristics of soil 

affect the health of the vegetation it supports by changing the availability 

of water and nutrients. 

Soil is composed of a diversity of mineral and organic components. Soil 

stores, cycles, and moderates the release of nutrients and other elements.

Soil sequesters carbon, reducing the prevalence of atmospheric carbon 

dioxide, a gas linked to climate change. In the Northeast, roughly as much 

carbon is stored in the soil, mostly in the form of organic matter, as in live 

biomass (e.g., trees) (Shifley et al., 2012).

In most ecosystems, soil biota help to regulate a number of key ecosystem 

services, including plant production, nutrient and carbon cycling, 

maintenance of soil structure, and water regulation (Wall et al., 2012).

Soil biota can have direct and indirect impacts on land productivity and 

other ecosystem functions, such as fresh water; food and pollination 

services; timber, fiber, and fuel; nutrient and waste management; and 

climate regulation (Barrios, 2007).

Vegetation alters soil nutrient cycling, especially in situations where 

certain vegetation types serve a unique ecological function. For example, 

maple trees are a critical component in soil nitrification in the Northeast 

United States, and their loss could affect nitrogen retention and cycling in 

forested watersheds (Lovett and Rueth, 1999).

Soils are categorized by type, which describe the physical properties of the 

soil (including permeability, water-holding capacity, soil texture, and soil 

structure), and its chemical properties (including pH, salinity, cation 

exchange capacity, organic matter, and carbon-to-nitrogen ratio). The 

Natural Resources Conservation Service categorizes soil type into 12 soil 

orders and 64 suborders (McDaniel, 2006). Based on their various 

characteristics, different soil orders and suborders have varying capacities 

to support ecosystem services (i.e., retain water, filter water impurities, 

cycle nutrients, anchor plant roots, and absorb air pollutants). As a result, 

disturbance affects different soil types to varying degrees and in a variety 

of ways.

Changes in physical soil characteristics occur when ground-based 

equipment makes repeated passes over the soil. These activities compact 

soils and, if soils are wet enough, can result in rutting and leaching of soil 

nutrients. Different soil types compact more readily than others; clay and 

loam soils generally compact more than sandy soils. These changes to the 

physical soil characteristics reduce the pore space and the ability of the 

1. Soil Types 

of the 

United States

38 III. Affected Environment
soil to retain water. In turn, this reduces infiltration rates, slows soil 

drainage, impedes root growth, and reduces plant-available water and 

nutrients. Physical soil disturbances also decrease gas exchange, affecting 

both plants and soil biota.

Organic matter affects the chemical soil characteristics. In its various 

forms, organic matter provides nutrients and retains moisture for soil 

organisms and plants. Because organic matter derives from decomposing 

plant material, the type of vegetation growing in an area influences the 

chemical composition of soil.

Soil quality refers to “the capacity of a soil to sustain biological 

productivity, maintain environmental quality, and promote plant and 

animal health” (Doran and Parkin, 1994). Erosion, compaction, loss of 

soil structure, loss of nutrient content, and changes in soil salinity degrade 

soil quality (Cook, 1990). Atmospheric acid deposition has led to a 

concentration of highly acidic soils in the Northeastern States and 

southward along the Appalachian Mountains (Shifley et al., 2012). A

continued increase in acidity is likely to make sensitive trees more prone 

to other stressors, for example, insect attacks. Soil types vary in response 

to different impacts and the preparation of EAs at the local or regional 

level for specific Program actions will address the site-specific issues.

The types of trees that grow in a forest ecosystem affect the quality of the 

forest soil. Predominant or “foundation” species often define the structure 

of a forest community by creating locally stable conditions for other 

species, and by modulating and stabilizing soil quality, productivity, and 

water balance (Dayton, 1972; Ellison et al., 2005). For example, red 

maple and sugar maple, high-risk host tree species for ALB, are two of the 

most common tree species in many Northeastern forests in the United 

States (Lovett et al., 2006), and play a critical role in shaping the physical 

and chemical aspects of the soil (Mroz et al., 1985). Removal of 

foundation tree species can have dramatic effects on ecosystem function 

and stability. The physical characteristics of trees within forest 

ecosystems define forest structure and alter microclimates, while the leaf 

litter contributes substantially to ecosystem processes, such as nutrient 

cycling (Ellison et al., 2005).

Host species that grow in riparian forest ecosystems offer a variety of 

ecosystem services specific to soil, including stability and nutrient cycling. 

The riparian zone is the interface between terrestrial and aquatic 

ecosystems through which water and materials move, and are often 

impacted by a change in soil conditions or vegetation (Knoepp and 

Clinton, 2009). The stability and nutrient cycling these ecosystems 

provide help to protect aquatic environments against excessive 

sedimentation, polluted surface runoff, and erosion. The overall health of 

2. ALBHost Species

and Soil 

Quality

III. Affected Environment 39
riparian forest ecosystems is critical to maintaining good water quality and 

the health of stream ecosystems (Knoepp and Clinton, 2009).

Soil erosion is the movement of soil particles by water, wind, or ice. 

Erosion is a natural process within ecosystems that removes and 

redistributes soil. However, anthropogenic activities (i.e., construction, 

agriculture) can accelerate erosion. A soil system is in equilibrium when 

soil erosion is in balance with the formation of new soil (Wall et al., 

2012).

In forested sites on steep slopes, water is generally the most common 

driver of erosion. Erosion is usually infrequent in undisturbed forest soils 

because organic matter provides a protective layer on the soil surface,

limiting the impact of raindrops, and allows water to infiltrate. The 

surface soil below the organic layer is generally porous, allowing water to 

infiltrate into and through the soil profile. Soil erosion can occur when the 

surface soil is compacted, or when the loose surface soil and its protective 

layer of organic material are changed or removed, such as by disturbances 

associated with management activities. 

Forest soils may be compacted by grazing animals and by the roots of the 

trees themselves, but more noticeably by vehicles used for a range of 

mechanized forest operations. Soil compaction drastically reduces the 

number and size of pores that naturally occur throughout the soil. This 

reduces the exchange of gases and infiltration of water through the soil.

Although compaction may allow surface soils to hold more water, it will 

tend to pool without soaking through to deeper layers of soil. In turn, 

runoff of surface water may increase, and tree growth may be reduced 

because of a reduced water supply, restricted root space, and poor 

aeration. In contrast, soil compaction may increase traction and, therefore,

increase efficiency of vehicles moving on roads and tracks in the forest. 

D. Air

This section provides a general overview of air quality as it pertains to the 

proposed action and alternatives. All site-specific assessments will 

include an analysis of local air quality, and may tier to this section of the 

programmatic EIS.

Air quality is affected by two types of pollutants (primary and secondary), 

and greenhouse gases (GHG) that can pollute the air for human health, 

forest health, visibility, acid deposition, and climate change. Primary 

pollutants, such as particulate matter (PM), volatile organic compounds 

(VOCs), carbon monoxide (CO), nitrogen oxides (NOx), and sulfur oxides 

(SOx) that can affect human health, are directly generated from sources 

such as industrial facilities, cars and other mobile sources, and forest 

3. Soil Erosion

40 III. Affected Environment
processes and activities, including fire (Stern, 1977). Secondary

pollutants, for example ozone (O3), are chemically transformed from 

primary pollutants such as VOCs and NOx (Stern, 1977). Forest fire 

emissions, when added to primary pollutants that affect human and forest 

health, contain carcinogenic air toxins such as acrolein, benzene, mercury, 

and formaldehyde (Langmann et al., 2009). Black carbon (BC) and 

GHGs, including carbon dioxide (CO2), methane (CH4), and nitrous oxide 

(N2O) affect climate. Pollutants such as sulfate (SO4), nitrate (NO3), and 

organic and elemental carbon (soot) reduce visibility (Stern, 1977).

Atmospheric GHGs, such as CO2 and CH4, can trap solar energy and 

affect climatic conditions (EPA, 2012b). Elevated temperatures can lead 

to higher ozone levels (EPA, 2012b). GHG emissions in the United States 

increased 7.3 percent from 1990 to 2009, primarily due to emissions from 

electricity generation and transportation (EPA, 2012b) (table 3–1).

Table 3–1. GHG Emissions in the United States Allocated by Source*

Source 1990 2005 2008 2009 2010 2011 2012

Energy 5,260.1 6,243.5 6,071.1 5674.6 5,860.6 5,712.9 5498.9

Industrial 

Processes 316.1 334.9 335.9 287.8 324.6 342.9 334.4

Solvent and 

other 

Product Use

4.4 4.4 4.4 4.4 4.4 4.4 4.4

Agriculture 473.9 512.2 543.4 538.9 534.2 528.3 526.3

Land-use 

change 13.7 25.5 27.3 20.5 20.0 36.0 37.8

Waste 165.0 133.2 136.0 136.5 131.1 128.5 124.0

Total 

Emissions 6,233.2 7,253.8 7,118.1 6,662.9 6,874.7 6,753.0 6,525.6

Land Use 

and Forestry 

(sinks)

(831.1) (1,030.7) (981.0) (961.6) (968.0) (980.3) (979.3)

Net 

Emissions 

(sources 

and sinks)

5,402.1 6,223.1 6,137.1 5,701.2 5,906.7 5,772.7 5,546.3

* Teragram (Tg), or million metric tons CO2 Eq. (Data source: (EPA, 2014b))

 

Different Federal, State, and local air regulatory agencies have created 

laws, rules, and regulations for control and reduction of air pollutants. 

Under the Clean Air Act (CAA), last amended in 1990, EPA set National 

Ambient Air Quality Standards (NAAQS) for pollutants considered 

harmful to public health and the environment (EPA, 2012a). NAAQS 

cover six criteria pollutants—sulfur dioxide (SO2), nitrogen dioxide 

(NO2), CO, ozone (O3), particulate matter (PM10 and PM2.5), and lead. 

III. Affected Environment 41
EPA requires all States to develop attainment plans (State implementation 

plans (SIPs)) to improve air quality in nonattainment areas.

Air quality monitoring data is collected and reviewed by EPA and State 

and local regulatory agencies, and is available to the public. This data is 

often published with respect to a local air quality index (AQI). AQI is a 

measurement of the level of pollutants in the atmosphere. An AQI above 

100 indicates that air quality conditions exceed human health standards, 

while values below 100 indicate pollutant levels are below air quality 

standards. An AQI that exceeds 100 suggests that air quality may be 

unhealthy for certain sensitive groups of people. 

In general, air quality is improving on a national scale, particularly

through regulations and voluntary measures taken by industry to reduce 

emissions (EPA, 2012b). Cleaner cars, industries, and consumer products 

have contributed to cleaner air for much of the United States (EPA, 

2012b). Control programs for mobile sources and facilities (e.g., chemical 

plants, dry cleaners, coke ovens, and incinerators) are primarily 

responsible for these reductions (EPA, 2012b). Despite the downward 

trend in pollutant levels observed across the United States, numerous 

counties have reported nonattainment for one or more of the six criteria 

pollutants (EPA, 2013a).

Trees have a beneficial effect on air quality by removing pollutants from 

the air, thus reducing human exposure to these substances and associated 

risk. Trees absorb CO2 from the atmosphere and release oxygen through 

photosynthesis (Shifley et al., 2012). Trees also absorb or intercept 

pollutant particles (PM10, e.g., dust, ash, dirt, pollen, and smoke) and 

gaseous pollutants (e.g., O3, NO2, and SO2) in the air, reducing human 

exposure to these substances and associated risks (Beckett et al., 1998;

Nowak et al., 2000; Nowak et al., 2006; Tiwary et al., 2009). One 

estimate implies that a mature urban tree can intercept up to 50 pounds of 

particulates per year (Dwyer et al., 1992). In urban areas, ozone, SO2 and 

nitrogen oxide are some of the most common pollutants, all of which trees 

may absorb (Bell and Treshow, 2002). Trees protect human health by 

reducing pollutant exposure which, in turn, can diminish respiratory 

illnesses related to pollutant exposure (Kim and Bernstein, 2009).

Forests can serve as a sink for GHG emissions, sequestering the gases that 

contribute to GHG levels (table 3–1). In 2009, estimates of the total 

carbon on forest land in the Northern States, including soil organic carbon, 

was 14,413 million dry tons, which represents about 32 percent stored on 

forest lands and soil in the United States (Shifley et al., 2012). In 2010, an 

estimated 12.4 billion tons of carbon was stored in Southern forests, 

within tree biomass, soil organic carbon, and understory plants above and 

below ground (Wear and Greis, 2013). Urban forests also contribute to 

42 III. Affected Environment
carbon sequestration. In an early estimate, urban forests stored 

approximately 800 million tons of carbon, nearly 5 percent of live tree 

carbon storage in all U.S. forests (Dwyer et al., 1992). Fifty-year 

projections indicate the forest carbon pool in the South is 5 percent smaller 

than the pool in 2010 (a net emission of about 600 million tons) (Wear and 

Greis, 2013). Trees release stored carbon when burned or through the 

decay process. Conversion of trees to lumber does not immediately 

release carbon stores within the tree. 

Trees can have some negative effects on air quality as well. Trees release 

natural VOCs, which play a part in the formation of ozone and carbon 

monoxide (Beckett et al., 1998). These VOCs also can congregate with 

other particles in the atmosphere to create a haze over some stands of trees 

(Beckett et al., 1998). In a 2005 study, national VOC emissions from 

biogenic (natural) sources were larger than the VOC emissions from 

anthropogenic (human caused) sources, accounting for approximately 

74 percent of VOC emissions (EPA, n.d.). Anthropogenic sources of 

VOCs are from industrial processes and manmade products, such as power 

plants, chemical production, solvents, vehicles, and other machinery 

(EPA, 2012b, n.d.). On a national level, anthropogenic VOC emissions 

have been declining (EPA, n.d.).

In the Northeast region of the United States (comprised of 20 States), 

42 percent of the land cover is forested (Shifley et al., 2012). Projected 

urban development and other land use will shift the location of forested 

land cover, but overall coverage in the region is expected to remain stable 

in the near term (Shifley et al., 2012). The loss of trees in developed areas 

will affect local air quality; however, the greatest contribution to air 

quality improvements over the last decade is due to the reduction of 

mobile and industry emissions. “EPA expects air quality to continue to 

improve as recently adopted regulations are fully implemented and States 

work to meet current and recently revised national air quality standards.” 

(EPA, 2012b). Stricter air-quality regulations anticipated in coming years 

may add to the regulatory constraints on use of prescribed burning (Wear 

and Greis, 2013).

E. Affected Biological Organisms

All aquatic and terrestrial plant, vertebrate, and invertebrate species living 

in the environments that could support ALB are part of the affected 

environment. Changes in the composition of tree species can alter 

ecosystems, and can affect the species dependent upon them. Biological 

diversity, a term given to the variety of life and the natural patterns it 

forms, provides a large number of goods and services that sustain our 

lives, including food security, fresh air and water, energy, and biologicalbased products, such as wood products. In forests, high biological 

III. Affected Environment 43
diversity enables these ecosystems to respond to external influences and 

recover from disturbances, while maintaining their ecosystem services, 

such as nutrient cycling, support to wildlife, and the purification of air and 

water (Shifley et al., 2012). Due to the importance of biological diversity 

in the health and sustainability of human populations, national and 

international programs and organizations work to preserve biological 

diversity, including the 150 Government-Member Convention on 

Biological Diversity, of which the United States is a member. Biological 

diversity is generally lower in suburban and urban forest communities and, 

in these areas, native species tend to be fragmented and small. Wildlife is 

usually limited to those species that are adapted to living near people, 

including raccoons, squirrels, deer, opossums, and a variety of birds. 

Domestic animals and pets also comprise a sector of animal life that 

cohabitates with people. Disturbances to wildlife through habitat 

destruction from development, traffic, and noise are common in developed 

communities. In contrast, less developed forest communities (e.g., State 

and national parks) sustain higher levels of biological diversity and harbor 

larger mammal species that tend to have a larger home range. In the 

Northeast region of the United States, forests support 780 known animal 

species (Shifley et al., 2012). Common mammals in the Northern forest 

include deer, black bear, porcupine, raccoon, and squirrel (Smith et al., 

2007).

Migratory birds contribute to the biological diversity in the United States 

and bring enjoyment to millions of Americans. Neotropical migratory 

birds depend on forest stands for nesting and foraging (Donovan et al., 

1995; Suarez et al., 1997). Neotropical bird species vary in their habitat 

preference; some species depend on interior forest habitats, while others 

prefer edge habitats (Suarez et al., 1997; Thompson, 2005). In response to 

the importance of migratory birds, the United States established the 

Migratory Bird Treaty Act for the conservation of migratory birds and 

their habitats. The contiguous United States has four migratory game bird 

flyways: Atlantic Flyway, Central Flyway, Mississippi Flyway, and the 

Pacific Flyway. Managed by FWS and its partners, the goal for

administering these flyways is to conserve migratory game bird species 

and allocate bird resources. Flyways are routes taken by a concentration 

of migratory birds between breeding and wintering areas. 

In the United States (not limited to the contiguous United States), there are 

over 1,400 (T&E) species federally listed through the Endangered Species 

Act. Approximately 60 federally listed species and their critical habitats 

co-occur with ALB-host trees and forest-dependent listed species in the 

Northeastern and mid-Atlantic areas (figure 4–2). Threatened species are 

plants and animals that are likely to become endangered throughout all or 

a significant portion of its range. 

44 III. Affected Environment
Endangered species are those plants and animals that have become so rare 

that they are in danger of becoming extinct. The forest tree composition 

and its interaction with the air, water, and soil resources (discussed 

previously) affect the habitats in which T&E species live. T&E species 

are generally more sensitive to changes in their habitats. The threatened 

Virginia round-leaf birch, Betula uber (species of Betula are hosts to 

ALB), is found in only one location in Smythe County, Virginia. 

According to FWS, Virginia round-leaf birch is associated with second 

growth deciduous and mixed conifer/deciduous forests. Vegetation 

associated with the known extant population of the species includes oakpine and maple-beech-birch associations, with some tendencies to elmash-cottonwood associations perhaps because of the riparian setting 

(Garrison et al., 1977). In prior EAs, USDA–APHIS consulted with FWS 

on several T&E species that occur in areas where the Program is operating 

(see table 3–2 for a list of these T&E species). Several species are forestdependent, including the Indiana bat (Myotis sodalis) (FWS, 2007), and 

the small whorled pogonia (Isotria medeoloides) (Mehrhoff, 1989).

State species of concern, as well as federally listed plant species that are 

preferred hosts for ALB, occur in areas where ALB could become 

established (NHNHB, 2008).

Table 3–2. Threatened or Endangered Species that Occur in Areas the 

Program is Operating*

Genus Species Common Name Type State Occurrence

Charadrius melodus Piping plover Bird Massachusetts

Cyprogenia stegaria Fanshell Aquatic mollusk Ohio

Epioblasma triquetra Snuffbox Aquatic mollusk Ohio

Isotria medeoloides Small whorled pogonia Terrestrial plant Massachusetts

Lampsilis abrupta Pink mucket pearly

mussel Aquatic mollusk Ohio

Myotis sodalist Indiana bat Mammal Ohio

Myotis septentrionalis+ Northern long-eared bat Mammal Ohio, NY, MA

Plethobasus cyphyus Sheepnose Aquatic mollusk Ohio

Setophaga kirtlandii Kirtland's warbler Bird Ohio

Trifolium stoloniferum Running buffalo clover Terrestrial plant Ohio

Villosa fabalis Rayed bean Aquatic mollusk Ohio

* T&E species previously analyzed by APHIS for the ALB Program; APHIS consulted with FWS.

+ Proposed for listing.

III. Affected Environment 45
Pollinators

Pollination is a process of fertilization that occurs through the transference 

of pollen granules from the anthers (male parts) of a flower to the stigma 

(female parts) of the same or different flower. This ensures that a plant 

will produce a full-bodied fruit, and a full set of viable seeds. Pollen 

moves from flower to flower by wind, rain, and gravity, as well as by 

pollinating animals, such as birds, bees, bats, butterflies, moths, beetles, 

ants, and other animals. Pollinators use both pollen and nectar as food 

sources; some pollinators (e.g., honey bee) survive exclusively on pollen 

and nectar collected from flowers.

In most terrestrial and aquatic environments, pollination and pollinators 

render vital ecological services. These services often have economic 

consequences; many agricultural crops rely on pollination to turn out the 

food on which humans and other animals depend for survival (AllenWardell et al., 1998). In fact, the ecological services that pollinators 

provide are necessary for the reproduction of over two-thirds of the 

world’s crop species, and 60 to 90 percent of the world’s flowering plants 

(Klein et al., 2007; Kremen et al., 2007).

Reproduction of many flowering plants in the forest ecosystem is 

dependent upon insect pollinators (Coulson et al., 2005). Forest 

fragmentation caused by tree removal affects plant-animal interactions. 

Fragmentation introduces “edge” into a landscape—the changes in 

population or community structures that occur at the boundary of two 

habitats. The restricted size, discontinuity, and increased edge of 

fragments may impose many ecological and genetic effects on plants, both 

directly and indirectly, through pollination (Aizen and Feinsinger, 1994).

Red maple, a regulated host of ALB in the United States, is an important 

early spring food resource for European honey bees (Apis mellifera) and 

other pollinators (Batra, 1985). When few other flowers are available, the 

red maple undergoes massive bloom between March and May, depending 

on elevation and latitude (Walters and Yawney, 1990). Boxelder and 

willow, both regulated hosts of ALB, are important food resources for 

mason bees (Osmia lignaria lignaria Say) during nest construction in the 

Northeastern United States and mid-Atlantic States (Kraemer and Favi, 

2005).

Global pollinator decline has become an issue of concern for agricultural 

crop science. In North America and many parts of the world, the viability 

of multiple agricultural crops and broader ecosystems is threatened by 

unsustainable declines in the populations of honey bees, bumblebees, and 

other insect pollinators (NRC, 2007; Pettis and Delaplane, 2010). Colony 

collapse disorder (CCD) is a recent, pervasive syndrome affecting honey 

46 III. Affected Environment
bee (Apis mellifera L.) colonies in the Northern Hemisphere, and is 

characterized by a sudden disappearance of adult honey bees from the 

hive. Multiple causes of CCD and general pollinator decline have been 

proposed, such as poor nutrition, pesticides, pathogens, parasites, and 

natural habitat degradation (Thompson, 2003; Desneux et al., 2007; Gill 

et al., 2012).

F. Affected Economic, Social, and Cultural Factors

Trees provide a range of products and support several industries within the 

United States. Tree species, such as those that are host trees for ALB,

provide timber, maple syrup, and nursery trees, and generate income 

related to recreational activities. These industries operate predominantly 

in less developed forest communities, including uninhabited forest and 

forest recreational areas; these are important to the economies of many 

communities in the United States. The discussion below focuses on 

market and non-market values in the Northeastern United States as the 

number of ALB-host trees is higher in those areas when compared to other 

parts of the United States. In 2006, the Northern States wood products 

industry and the pulp and paper industry was estimated at $112 billion;

primary wood products added $52 billion to the economy (Shifley et al., 

2012). Hardwood trees compose the majority of the industry in the North 

(Shifley et al., 2012). Economic returns on the market factors discussed 

below would be much greater when considering all States where ALBhost trees are present.

The volume of sawtimber varies from State to State when making 

comparisons between Northeastern States where a significant amount of 

ALB-host trees are present (table 3–3). Sawtimber refers to a growing

stock tree containing at least a 12-foot saw log or 2 noncontiguous sawlogs

8 feet or longer, free from defects. The percentage of hardwoods that are 

ALB-host trees ranges from 24 percent for Rhode Island to 65 percent for 

Vermont. 

Timber from ALB-host trees has a variety of uses in roundwood products 

within these nine States. Roundwood products are logs, bolts, or chips cut

from trees for industrial and nonindustrial uses (sawlogs, veneer logs,

pulpwood, fuelwood, etc.) (FS, 2014). A majority of the volume from 

these tree species in these Northeastern States is used as sawlogs or as 

fuelwood (table 3–4) (APHIS, 2009).

This production of timber products translates into hundreds of millions of 

dollars in value in the Northeastern States. The total value of host species 

sawlogs for the eight States, as shown in table 3–5 (New Jersey is not 

included because stumpage prices were not available), was $171 million in 

2006. Production of veneer logs was worth an additional $720,000 in

1. Market 

Factors

2. Timber

III. Affected Environment 47
Table 3–3. Volume of Sawtimber (ALB-Host Species) in Northeastern

States and the State of Ohio—2012.

State Net Volume*

(billion board feet)

% of Hardwood 

Volume at Risk

% of Total Volume

at Risk

Massachusetts 5.55 40% 22%

Connecticut 4.53 35% 30%

Maine 12.08 60% 21%

New Hampshire 7.49 49% 24%

Vermont 14.19 65% 38%

Rhode Island 0.43 24% 16%

New York 32.94 47% 35%

New Jersey 1.85 30% 15%

Pennsylvania 40.67 36% 34%

Ohio 17.33 36% 34%

* Net volume eguals gross volume less deductions for other defects that affect use for lumber.

(Source: USDA–FS (2014), Northern Research Station (NRS-171:188)).

 Table 3–4. Volume of Roundwood Products (ALB-Host Species) in the Northeastern

States—2006.

Sawlogs

Veneer 

Logs Pulpwood

Composite 

Products

Fuelwood

Postpolespilings

Other 

Products

All 

Products

State MCF *

Connecticut 1,264 0 97 0 2,094 0 0 3,457

Maine 19,211 0 0 0 2,506 0 0 21,718

Massachusetts 950 0 0 0 7,095 0 0 8,044

New Hampshire 12,320 572 0 0 2,880 0 48 15,822

New Jersey 323 0 32 0 5,641 0 0 5,998

New York 28,902 588 21,879 1,440 41,805 0 2 94,612

Ohio** 60,272 478 23,538 695 No 

data 0 0 91,204

Pennsylvania 33,828 2,656 2,368 0 1307 298 554 41,014

Rhode Island 81 0 0 0 49 0 0 130

Vermont 12,360 0 0 0 7,598 0 0 19,956

TOTAL 109,239 3,816 24,376 1,440 70,975 298 604 210,751

*

= Thousand cubic feet 

** Data for Ohio is for 2010. (Source: (FS, 2009b))

New York. Fuelwood production of host species was worth an additional 

$6.6 million in 2006. Although there is substantial fuelwood production 

in many States, the overall value of this product is less because the prices 

for fuelwood are significantly lower than many other products. Host 

48 III. Affected Environment
species are also used for pulpwood, composite products, and other 

products in some Northeastern States, but are not valued here due to lack 

of price data (APHIS, 2009).

Table 3–5. Value of Selected Timber Products for Species and State—2006.

CT ME MA NH NY PA RI VT

(million dollars)

Sawlogs

(Total) 0.833 22.313 0.586 10.033 67.245 49.014 0.087 20.463

Ash 0.131 0.000 0.107 0.552 8.438 2.189 0.002 1.423

Sugar Maple 0.451 13.503 0.312 3.947 45.238 23.474 0.073 17.047

Red Maple 0.117 2.266 0.070 1.833 13.410 15.182 0.010 0.000

Yellow Birch 0.049 4.119 0.025 2.421 0.075 0 0.001 1.381

Other Birch 0.025 2.425 0.045 1.281 0.026 0 0.001 0.611

Elm 0 0 0 0 0.005 0 0 0

Poplar 0.060 0 0.027 0 0.053 8.169 0.001 0

Veneer 

Logs*

(Total)

0 0 0 NA 0.7196 NA 0 0

Ash 0 0 0 NA 0.1323 NA 0 0

Sugar Maple 0 0 0 NA 0.3437 NA 0 0

Red Maple 0 0 0 NA 0.2391 NA 0 0

Yellow Birch 0 0 0 NA 0.0036 NA 0 0

Other Birch 0 0 0 NA 0.0007 NA 0 0

Elm 0 0 0 NA 0.0002 NA 0 0

Poplar 0 0 0 NA 0.0001 NA 0 0

Fuelwood 0.137 0.501 0.466 NA 4.703 NA 0.003 0.807

TOTAL 0.970 22.815 1.052 10.033 72.668 49.014 0.090 21.270

Price data was not available for veneer logs and fuelwood in NH and PA. (Source: (APHIS, 2009))

The United States exports sawlogs to various countries. Figure 3–2 shows 

historical trends for the U.S. hardwood log exports for four ALB-host

species. In 2008, log exports for birch, ash, maple, and yellow poplar 

were valued at $153 million in total (FAS, 2009). Historically, exports of 

maple logs have been the highest in value of the four species; however, the 

total value of maple log exports has been decreasing since 2005. These 

four ALB-host species comprise 21 percent of the value of all U.S. 

hardwood log exports in 2008 (APHIS, 2009).

In 2012, log exports for birch, ash, maple, yellow poplar, and cherry (not a 

host of ALB) were valued at $188.7 million in total (GTIS, 2013). China

III. Affected Environment 49
Figure 3–2. U.S. hardwood log exports for select ALB-host species, 1989–2008. 

(Source: (FAS, 2009)

accepts the largest percentage of these exports at 33 percent, followed by 

Canada at 25 percent, European Union countries at 12percent, Vietnam at 

8 percent, Japan at 4 percent, and Thailand, Turkey, and Hong Kong at 

2 percent each (GTIS, 2013).

In addition to timber production, ALB-host trees (e.g., maple) provide 

economic returns through maple syrup production. In 2013, total maple 

syrup production in the Northern region exceeded $131 million, with 

3.5 million gallons collected (tables 3–6 and 3–7). Production in 2013

was greatest in Vermont with 1.4 million gallons ($49.4 million), followed 

by New York with 574,000 gallons ($25 million), and Maine with 

560,000 gallons ($17.9 million) (tables 3–6 and 3–7). Other Northeastern 

States producing maple syrup include New Hampshire, Pennsylvania, 

Massachusetts, Connecticut, and Ohio, each of which produces 

200,000 gallons or less annually. Demand in the United States has been 

increasing; currently only 0.4 percent of tappable maples are being 

utilized, suggesting that economic returns and production could increase if 

demand continues (Farrell and Chabot, 2012).

0

20,000

40,000

60,000

80,000

100,000

120,000

19891990199119921993

1994199519961997199819992000

20012002200320042005200620072008

Value (Thousand dollars)

Year

Hardwood Log Exports

Birch

Ash

Maple

Yellow Poplar

3. Maple Syrup

50 III. Affected Environment
Table 3–6. Maple Syrup Production 2010–13.

Production (1,000 Gallons) 

2010 2011 2012 2013

Vermont 890 1,140 750 1,480

New York 312 564 360 574

Maine 315 360 360 560

New Hampshire 87 120 76 124

Pennsylvania 54 128 96 134

Massachusetts 29 62 40 63

Connecticut 9 17 11 20

Ohio 65 125 100 155

TOTAL 1,960 2,794 1,908 3,523

Source: U.S. Crop Production, June 2014 USDA–NASS and USDA–NASS, New England Field 

Office, June 2014.

The tree nursery industry grows ALB-host trees. Between 2005 and 2009, 

producers in Pennsylvania sold 479,950 deciduous shade trees (not all 

were hosts of ALB) for $12.4 million; producers in New Jersey sold 

300,119 trees for $22.2 million; producers in New York sold 363,008 trees 

for $12 million; and, producers in Ohio sold 218,341 trees for 

$16.6 million (USDA, 2009). Within four Northeast States (Connecticut, 

New Jersey, New York, and Pennsylvania) there were 216 producers with 

over $56 million dollars in gross sales in 2006 (USDA, 2009).

Non-market factors relate to the benefits of ALB-host trees in residential 

and developed forest communities. Aesthetic values for residents and

tourists; use values from recreation activities such as hiking, hunting, bird

watching, and fishing; and ecosystem values from watershed services and

carbon sequestration are examples of non-market factors related to urban 

and forested areas where ALB-host trees occur. Recreational activities, 

including fall foliage and wildlife viewing, hiking, and hunting generate

revenue for many States. For example, visitors to Vermont spend

$1.719 billion in the State annually, of which approximately 27 percent

($460 million) occurs during the fall season, from September through

November (University of Vermont Tourism Data Center, 2012). Direct

expenditures of visitors to Maine totaled $4.9 billion in 2012.

Approximately 31 percent of trips to Maine occur during the fall season 

(October through November), which would account to around $1.5 billion 

in direct spending. Fifty-five percent of Maine visitors reported “beautiful 

scenery” as a motivation for their visit (DPA, 2013).

Many factors affect tree value and benefits, including species composition, 

age distribution, condition, amount of canopy cover, and location. Urban

trees provide valuable benefits to residents, including air temperature

4. Tree 

Nurseries

5. Non-Market

Factors

III. Affected Environment 51
regulation, carbon sequestration, pollution reduction, stormwater runoff

reduction, and lowering heating and cooling costs by serving as 

windbreaks, and casting shade resulting indirectly in the reduction of 

emissions from energy generation (Huang et al., 1987; Dwyer et al., 1992;

McPherson and Simpson, 1995; Akbari et al., 1997; Simpson, 1998;

McPherson, 2005). However, trees can also have the opposite effect and 

increase energy costs by casting shade on buildings in the winter, or 

blocking cooling winds in the summer (Nowak, 2002).

In a literature review conducted by EPA, studies have found general 

increases of about 3 to 10 percent in residential property values associated 

with the presence of trees and vegetation on a property (EPA, 2008).

Homeowners generally place a high value on their trees for shade, 

aesthetics, privacy, investment, and wildlife habitat, and are, consequently,

concerned when this resource is threatened.

The forestry industry supplies jobs to thousands of people, and is a 

dominant employer in some communities. In the Northern States,

441,000 workers are employed in forest management, logging, forest 

products, and pulp and paper industries (Shifley et al., 2012). Other 

benefits of urban trees to society, that are more difficult to quantify,

include increased job satisfaction, sentimental attachment, and improved 

child development (Kane and Kirwan, 2009).

A person’s health is affected by the quality of the environment where they 

live. Access to greenness varies among demographic groups (Donovan et 

al., 2013). Trees are an important part of the natural environment, 

particularly in urban areas where they provide various health benefits to 

humans (Sarajevs, 2011), in addition to scenic views and environmental 

benefits.

Trees can reduce stress and have positive physiological and psychological 

effects on human health (HCN and DAC, 2004; Guite et al., 2006). For 

example, post-surgical patients had shortened hospital stays and a reduced 

need for pain-relieving drugs when they viewed trees through their 

windows (Ulrich, 1984). People recovered faster from stress, mental 

fatigue, illness, and experienced a long-term overall health and well-being 

improvement after viewing natural landscapes (Velarde et al., 2007; Lee 

et al., 2009). Trees reduce noise levels resulting in reduced stress and 

improved mental health (Sarajevs, 2011).

Trees also decrease human exposure to ultraviolet radiation through 

shading, which can reduce eye cataracts, and morbidity and mortality from 

skin cancer (Heisler and Grant, 2000; Heisler et al., 2003; Heisler, 2010;

Grant et al., 2002). Greater tree-canopy cover has also been associated 

with improved birth outcomes, suggesting that trees may affect the health 

6. Social Factors

52 III. Affected Environment
of a pregnant woman and reduce the risk of babies being born underweight 

(Donovan et al., 2011).

Trees are part of urban green space that provides an environment 

conducive to physical activity. When there are green areas in the 

neighborhood, people tend to spend a greater amount of time outdoors and 

are more physically active (Humpel et al., 2002; Tzoulas et al., 2007).

Children are less prone to become overweight when green space is 

available (Bell et al., 2008). Seniors in urban areas live longer when there 

are walkable green spaces along streets (Takano et al., 2002). Trees 

positively affect behavior and reduce crime (Kuo and Sullivan, 2001a;

Kuo and Sullivan, 2001b; Taylor et al., 2002).

Trees affect the air, water, and soil in and around cultural and 

archaeological resources, as described in the respective sections above. 

Placement of trees around cultural, historic, and archaeological resources 

affect the aesthetic quality of the historic resource, and possibly the 

physical quality by providing wind buffer, shading, particulate adsorption, 

hydrological functions, and other protective attributes. Trees also can 

negatively affect cultural resources by damaging resources through falling 

limbs or trees, root growth, pollen production, and other natural 

phenomena.

Trees themselves may also be part of the cultural traditions and heritage of 

various human groups. For example, wood fiber from ash trees is an 

important material used in baskets made by several Native American 

communities. Loss of ash trees in the United States from infestations of 

the emerald ash borer has affected the availability of this core resource to 

tribal communities (http://www.emeraldashborer.info/files/EABImpacts 

OnAmericanIndianCommunities.pdf).

7. Cultural 

Factors

III. Affected Environment 53
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54 III. Affected Environment
IV. Environmental Consequences

The purpose of this chapter is to discuss the potential impacts related to 

each of the proposed alternatives. Information presented in Chapter 3, 

Affected Environment, serves as the baseline for the evaluation of impacts 

to human health and the environment from the proposed alternatives. The 

potential impacts reflect those identified in the scoping notice and 

applicable comments received during the scoping process for this EIS, as 

well as the impacts evaluated in previous NEPA documentation for the 

ALB Eradication Program. Due to the programmatic nature of this EIS, 

the discussion in this chapter is a qualitative evaluation of the impacts of 

the proposed alternatives. A quantitative approach is used where possible 

and, in some cases, analysis for a specific geographic area is used as an 

example to relate the potential impacts of a proposed alternative. The 

information in this section, and the relevant appendices, are also

applicable to a site-specific environmental analysis for an ALB outbreak.

A. Program Alternatives

a. Forest Resources

Under the no action alternative, a worst-case scenario model where ALB 

appears all at once in the Northeastern United States without mitigation in 

place, estimates a loss of 71 billion board feet of wood within 25 years,

and death of all host trees within 60 years (Jacobson et al., 2012). This 

would be a loss of about 45 percent of the forest (Jacobson et al., 2012),

followed by succession with non-host plant and tree species that would 

result in a change in the current forest composition. This vegetation could 

replace ecological and economic voids left by the loss. For example, the 

growth of non-host trees may open other wood product markets. ALB has 

been in the United States for approximately 20 years. Under no 

eradication or mitigation measures, ALB populations would expand 

through natural spread. The spread of ALB through human-mediated 

pathways would also likely occur without quarantine restrictions. 

b. Environmental Resources

(1) Water

Tree loss and defoliation of ALB-infested trees have the potential to 

impact water quality. Many of the preferred hosts for ALB are tree 

species that occupy riparian and wetland areas. Riparian zones ensure 

high quality stream habitat for aquatic fauna. Loss of tree cover and 

density from ALB infestations can have negative impacts on streambank

stabilization, water temperature, sediment loading, hydrology (increasing 

1. Alternative 1: 

No Action

IV. Environmental Consequences 55
runoff), nutrient cycling, and contaminate removal in aquatic habitats

(Wenger, 1999; Lee et al., 2004; Jones et al., 2006). The degradation in 

water quality from the loss of riparian function can also impact drinking 

water supplies, which has implications for human health.

(2) Air

Trees intercept pollutants from the air, reducing human exposure and 

associated risks, such as respiratory illnesses (Beckett et al., 1998; Nowak 

et al., 2000; Bell and Treshow, 2002; Nowak et al., 2006; Lovasi et al., 

2008; Kim and Bernstein, 2009; Tiwary et al., 2009; Donovan et al., 

2013). The estimated total annual air pollution removal for ozone, 

nitrogen oxides, sulfur oxides, carbon monoxide and particulate matter by

urban trees in the United States was at 711,000 metric tons (Nowak et al., 

2006). One estimate implies that a mature urban tree can intercept up to 

50 pounds of particulates per year (Dwyer et al., 1992). Trees infested 

with ALB reach mortality within 10 to 15 years. During the declining 

stage, trees continue to intercept air pollutants and sequester carbon 

dioxide. However, stress to these trees decreases their ability to sequester 

carbon dioxide (Bréda et al., 2006). The loss of trees from ALB would 

cause a reduction in the interception of air pollutants and other air quality 

improvements; however, through natural succession or replanting with 

non-host trees, the air quality contributions would recover over time. 

Trees sequester the gases, including carbon dioxide, that contribute to 

GHG levels. During photosynthesis, plants and trees absorb carbon 

dioxide, store carbon above and below ground, and release oxygen as a 

byproduct. Trees release carbon back to the atmosphere through 

respiration, decomposition, and burning. Conversion of trees to lumber 

does not immediately release carbon stores within the tree. In 2009, 

estimates of the total carbon on forest land in the northern States, 

including soil organic carbon, was 14,413 million dry tons, which 

represents about 32 percent of the stored carbon on forest lands and soil in 

the United States (Shifley et al., 2012). In 2010, an estimated 12.4 billion 

tons of carbon was stored in southern forests within tree biomass, soil 

organic carbon, and understory plants above and below ground (Wear and 

Greis, 2013). Urban forests also contribute to carbon sequestration. In an 

early estimate, urban forests stored approximately 800 million tons of 

carbon, nearly 5 percent of live tree carbon storage in all U.S. forests 

(Dwyer et al., 1992).

Climate change is the global shift in climate and weather from increased 

temperatures, mostly because of human activity. Carbon dioxide (CO2)

and GHGs trap solar energy in the atmosphere, leading to increases in 

temperature. Trees, including ALB-host trees, store carbon and play a role 

in the reduction of CO2 in the atmosphere. The loss of trees to ALB 

56 IV. Environmental Consequences
reduces carbon sequestration, and the decomposition of dead trees release 

CO2 into the atmosphere. 

Climate change may affect the distribution of host trees and ALB. In a 

study of Northeastern U.S. forests, 36 out of 80 species assessed show the 

potential to shift their growing range approximately 62 miles (100 km) to 

the north, including 7 that could shift greater than 155 miles (250 km) 

(Iverson and Prasad, 1998). Sugar maple (Acer saccharum, 14.5%) and 

black cherry (Prunus serotina, 10.0%) would decline sharply, while oak 

and southern pines would expand northward. Temperature increases 

caused by climate change could affect ALB’s life cycle. In cold climates, 

ALB produces one generation every 2 years. In the areas of the 

United States where ALB has established, the insect typically produces 

one generation per year. The observance of one generation every 2 years 

may be possible if ALB establishes in colder climates in the United States. 

However, future increases in temperature may shift this to one generation 

per year. 

In the extreme scenario where ALB infests all host-tree species in the 

contiguous United States, (13.9 million metric tons (mt)) of CO2 would be 

released over time (depending on the rate of tree decomposition) to the 

atmosphere in the absence of any eradication (appendix D). If released in 

a single 1-year pulse, this would represent 37.8 percent of total global CO2

annual emissions, based on the Year 2010 estimate of 9.1 Gt C/year (33.5

gigatons (Gt) CO2) global emissions from industrial sources and an 

estimated total of 10.0 Gt C/year, including land-use change and 

deforestation (http:// co2now.org/Current-CO2/CO2-Now/global-carbonemissions.html). It is likely that this would have a significant but transient 

impact on overall climate change.

Forests are capable of undergoing carbon recovery. Through sequestration 

in new growth, tree regeneration would recapture the equivalent of the 

CO2 released within 76 years (appendix D). Under improved management 

of tree health and tree cover, the level of CO2 sequestration in new tree 

growth could exceed initial losses due to tree mortality, and recapture fully 

all CO2 within as little as 43 years (appendix D).

(3) Soil

The loss of host trees in forests where ALB-host trees are dominant would 

alter soil nutrient cycling, especially in situations where a host tree serves 

a unique ecological function. For example, maple trees are considered a 

critical component in soil nitrification in the Northeastern United States;

this loss could impact nitrogen retention and cycling in forested 

watersheds (Lovett and Rueth, 1999; Lovett and Mitchell, 2004).

IV. Environmental Consequences 57
A decrease in maple stands from ALB infestation, would lead to higher 

nitrogen retention in soils and reduction in nitrogen transport into aquatic 

systems. The alteration of nitrogen cycling from the loss of maple would 

alter plant succession and diversity in terrestrial environments, as well as 

impact aquatic ecosystems, that are dependent on higher nitrogen inputs. 

Impacts to nitrogen cycling in forested ecosystems have been reported 

with other defoliating invasive forest insects (Kizlinski et al., 2002; Lovett 

et al., 2002). Additional soil impacts may include increased soil erosion 

and increased soil temperature from the loss of trees, or foliage dieback 

resulting from repeated ALB infestations. 

c. Ecological Resources

The dieback over successive seasons and loss of trees because of ALB 

infestation could result in a reduction of forested stands where ALB-host 

trees are dominant, and form canopy gaps in mixed forest habitats where 

ALB-host trees are present. The creation of canopy gaps and edge forest 

habitat can adversely impact those species that depend on contiguous 

blocks of forest for nesting and reproduction. In particular, neotropical 

migratory birds may be impacted by the loss or alteration of forest stands 

from ALB infestations. The species of birds impacted vary depending on 

whether it is dependent on interior forest habitats or edge habitats. Those 

species dependent on interior forest habitats may be negatively impacted 

due to the loss of habitat, while edge-dependent species may benefit. The

loss of habitat for nesting and foraging impacts reproduction. For 

example, some neotropical migratory bird species could be negatively 

impacted by increased nest parasitization and predation from birds (e.g., 

brown-headed cowbird) in forested areas fragmented by the loss of ALBhost trees (Thurber et al., 1994; Donovan et al., 1995; Suarez et al., 1997;

Thompson, 2005).

Impacts to migratory birds vary by species and its habitat requirements, as 

well as the size of the ALB infestation (Chalfoun et al., 2002). Federal 

and State natural resource agencies, as well as non-governmental 

organizations, recognize the importance of habitats to migratory birds; 

these habitats are protected through bird conservation plans and bird 

conservation regions (BCRs). Two of those regions where ALB-preferred 

host plants are prevalent are the Atlantic Northern Forest and the 

Appalachian Mountain BCRs (FWS, 2006). The conservation plans for 

these areas identify threats to a range of bird species by invasive species,

and forest habitat loss is a concern for multiple species. The added 

impacts from an ALB infestation on these regions increase the difficulty in 

implementing effective restoration and habitat protection plans. 

As with birds, other terrestrial fauna that depend on ALB-host trees and 

contiguous forested areas may be negatively impacted. Based on the 

58 IV. Environmental Consequences
spatial scale of forest loss, these impacts vary and are dependent upon the 

specific habitat requirements of the species. Canopy gaps or open areas 

resulting from an infestation may benefit some species while selecting 

against others that depend on ALB-host trees or depend on contiguous 

forest stands. Certain species may benefit from ALB-infested trees, such 

as secondary wood-boring pests and associated vertebrates that depend on 

snags for habitat and prey. 

A reduction in canopy cover or complete loss of ALB-host trees would 

favor understory vegetation. This would benefit species that depend on 

fragmented stands, and would create more open riparian areas for foraging 

and nesting (Bell and Whitmore, 2000). However, potential benefits to 

certain species from the loss of ALB-host trees are minor compared to 

widespread terrestrial and aquatic benefits related to the conservation of 

forested habitats.

In addition to upland areas that could be impacted by ALB infestation, 

many of the preferred host trees for ALB commonly occur in riparian 

areas; impacts to these habitats can have negative impacts to bird species, 

as well as amphibians and other terrestrial, semi-aquatic and aquatic fauna 

(Naiman and Decamps, 1997; Petranka and Smith, 2005; Perkins and 

Hunter, 2006). Riparian areas are dynamic and complex habitats that serve 

as an interface between terrestrial and aquatic ecosystems, providing 

unique functions that, if significantly impacted, have negative 

consequences to a wide range of ecological processes within terrestrial and 

aquatic ecosystems (Naiman and Decamps, 1997). These areas provide 

biodiversity and habitat for numerous species, and regulate nutrient 

cycling and microclimate conditions in terrestrial and aquatic ecosystems. 

The loss of ALB-preferred host trees that are typical in these areas would 

impact the function of riparian zone habitats. In cases where ALB-host

trees decline or are lost, other plant species grow that may contribute 

different or lower nutritive qualities, and alter decomposition rates. This 

can impact aquatic vertebrate and invertebrate species that exist in the

particular habitat (Smock and MacGregor, 1988). The magnitude of 

impacts would vary, depending on the density and abundance of host trees 

and the plants and animals that rely on them for habitat. 

Figure 4–1 shows the types of direct and indirect impacts that could occur 

to representative nontarget aquatic and terrestrial species that are 

dependent on ALB-host trees.

IV. Environmental Consequences 59
Figure 4–1. Direct and indirect effects of ALB establishment to representative aquatic and

terrestrial organisms.

d. Economic, Social, and Cultural Resources

Both market and non-market impacts will occur as ALB-host trees are lost 

to the insect. Impacts will vary depending on the density of host trees in 

an area, the rate of spread of the insect, and the rate of decline of the trees. 

Hardwood trees compose the majority of the tree product industry in the

north (Shifley et al., 2012), although not all of these are ALB hosts.

Under a worst-case scenario model where ALB establishes in all 

Northeastern States, the loss of ALB-host trees in the Northeast region of 

the United States would result in a $20 billion loss of harvestable timber

over 100 years, using a 3 percent discount rate to reflect the time value of 

60 IV. Environmental Consequences
money (Jacobson et al., 2012). This estimate takes into account the 

replacement of ALB-killed trees with other harvestable trees. 

The Northeastern region accounts for most of the maple syrup production 

in the United States and, based on the worst-case scenario where all 

maples would be lost, the maple syrup industry valued at $131 million in 

2013 would be lost (NASS, 2014). The tree nursery industry would lose 

part of their inventory; however, for those nurseries that carry non-host 

trees or are able to convert their inventory to non-host trees, an economic 

recovery may occur. Tree industries located within quarantine boundaries 

could incur additional costs due to restrictions (including treatments) 

imposed on the movement of ALB-host material. 

Countries listing ALB as a quarantine pest would restrict trade of 

commodities derived from host trees located within quarantine areas. 

Trees differ in the quality and utility of their wood. If replacement tree 

species do not meet export market needs, revenue from exports would 

decline. The United States may increase imports of timber and wood 

products derived from ALB-host trees should the country lose its domestic 

source.

Other forest product industries could benefit from the loss of host trees. 

For example, host trees would supply material for firewood, biofuels, and 

pulpwood. However, a surplus in supply may cause a decrease in price for 

the commodity because the supply is greater than the demand. 

An immediate disappearance of ALB-host trees is unlikely to occur; 

rather, the natural spread of ALB is expected to occur slowly, as would the 

death of host trees, based on observations in the United States and 

elsewhere. As ALB-host trees disappear, other tree species may take their 

place, potentially sustaining the forestry industry, perhaps with the 

exception of the maple syrup industry. ALB is not the only problem 

affecting the health of Northeastern forests. Other invasive pests and 

diseases, as well as environmental stress (including that from climate 

change) and development pressures are affecting forest health throughout 

the United States. These stressors would be expected to affect forest 

recovery from ALB. 

Research measuring the non-market value of trees is limited. The loss of 

ALB-host trees, particularly in areas dominated by these species, would

change the composition and age of tree stands. Outdoor recreationists 

prefer areas with older trees (Scarpa et al., 2000; Englin et al., 2006),

along with a preference for sites with more deciduous trees versus 

evergreen trees (Scarpa et al., 2000).

IV. Environmental Consequences 61
Changes in forest composition, particularly with the loss of maples and 

other hardwood trees, would negatively affect the fall foliage tourism in 

the Northeastern United States. Maples and other hardwood trees provide 

much of the brilliance in fall foliage. For example, in New Hampshire, 

fall foliage viewing contributes $292 million annually to the State’s 

economy (NH Dept. of Environ. Svcs.). Visitors to Vermont spend

$1.719 billion in the State annually, of which, approximately 27.0 percent

($460 million) occurs during the fall season from September through

November (University of Vermont Tourism Data Center, 2012).

The loss of mature host trees would diminish the value and aesthetics of 

residential properties. Several studies show a correlation between both the 

presence and health of trees on property values (Holmes et al., 2006; Price 

et al., 2010). Holmes et al. (2006) studied the impact of hemlock wooly 

adelgid infestations on residential housing prices in northern New Jersey; 

a positive correlation was found between healthy hemlock trees and 

housing prices, and a negative correlation between infested hemlock trees 

and housing prices. In this study, unhealthy hemlock trees, up to 

0.62 miles (1 km) away from the property, had a negative effect on 

housing prices.

A study in Portland, Oregon showed that street trees added an average 

$8,870 to sales prices, and reduced the time of housing on the market by 

1.7 days (Donovan and Butry, 2010). Other positive attributes trees 

impart to infrastructure include protection from stormwater runoff, 

temperature regulation, and electricity usage reduction, which would be 

affected by the loss of host trees. These effects would diminish over time 

as replacement trees mature. 

Human Health 

Under the no action alternative, ALB would continue to spread resulting in 

potential impacts to human health due to loss of trees. Tree loss in urban 

and rural residential areas was associated with declining cardiovascular 

and lower-respiratory-tract illness in an ecological study evaluating the 

relationship between the presence of emerald ash borer and human health

(Donovan et al., 2013). Tree loss from the spread of the emerald ash borer 

among 15 States was associated with 6.8 additional deaths per year per 

100,000 adults over the 18-year period for the study (1990–2007) 

(Donovan et al., 2013). Tree loss contributes to risk factors for 

cardiovascular and respiratory diseases including stress, lack of physical 

activity, and poor air quality (Pope III et al., 2003; Everson-Rose and 

Lewis, 2005; Lucas and Platts-Mills, 2005; Donovan et al., 2013).

Uncontrolled tree loss reduces the health benefits of trees discussed in 

chapter 3, and may cause negative effects on human health. 

62 IV. Environmental Consequences
Tree loss can cause stress and have psychological effects (Velarde et al., 

2007; Whitelaw et al., 2008). A comparison study on psychophysiological 

stress recovery and directed attention restoration of young adults, in 

natural and urban field settings, showed that natural settings with tree 

views have a positive impact on improved attention functioning, and 

lowered blood pressure levels (Hartig et al., 2003). This study found an 

increased positive affect and decreased anger for individuals in a natural 

reserve (Hartig et al., 2003). Another study analyzed survey results from 

953 individuals in 9 Swedish cities correlated increased participation in 

outdoor urban, open-green spaces with reduced stress levels (Grahn and 

Stigsdotter, 2003). (An open-green space is any open piece of 

undeveloped land with public access that is partly or completely covered 

with grass, trees, shrubs, or other vegetation.) Stress may also come from 

other sources, including decreased property values, and increased heating 

and cooling costs associated with tree loss (APHIS, 2013b). Tree loss can 

increase human exposure to ultraviolet (UV) radiation by removing the

shading effects from trees that provide UV-radiation protection. UV

radiation can negatively affect human health, primarily causing skin 

cancer and eye cataracts. UV radiation can also positively affect human 

health because it is essential for the synthesis of vitamin D. Vitamin D is 

required for bone health, and can reduce non-skin cancers. 

a. Forest Resources

In one study, researchers modeled a worst-case scenario where ALB 

infests all host trees in the Northeastern United States all at once, with no

eradication or mitigation programs in place. In this scenario, the Program 

would need to remove host trees from approximately 45 percent of the 

forested area (not including urban forests) (Jacobson et al., 2012).

However, based on the historical introduction and spread of ALB, as well 

as APHIS’ response to the pest, the percentage of trees removed would be 

less, and would not occur throughout the United States or the Northeastern 

States all at once. APHIS has removed woodlot areas in Massachusetts 

and Ohio, resulting in the removal of hundreds of trees from one location. 

Urban forest cover would diminish if ALB-host trees dominate streets,

parks, or residential plantings, as observed in cities and townships in 

Illinois, New York, New Jersey, Massachusetts, and Ohio. Regrowth of 

trees on woodlots through natural succession would take many years. 

Similarly, recovery of urban tree canopy cover will also take some time as 

replacement trees will likely be with immature non-host trees. 

Canopy cover influences understory plant composition, structure, and 

diversity (Oliver and Larson, 1996). Understory vegetation serves an 

important role in ecosystem health, biodiversity, and nutrient cycling, as 

well as contributions to soil and water quality in forests and wooded urban 

areas (Yarie, 1980; Oliver and Larson, 1996). Many vertebrate and 

2. Alternative 2: 

Removal of 

Infested 

Trees

IV. Environmental Consequences 63
invertebrate species depend on understory vegetation (Oliver and Larson, 

1996; Koide and Wu, 2003; Pineda et al., 2005). The removal of trees 

infested with ALB would reduce the canopy cover, creating an 

environment favorable to shade-intolerant vegetation.

The process of removing trees can damage surrounding vegetation. Felled 

trees, vehicles, and other tree removal equipment can compress vegetation 

and soil. The introduction of weeds and invasive plant species on 

equipment could alter the vegetative understory. In some instances, the 

Program applies an herbicide to stumps to prevent sprouting, although the 

preference is to grind the stumps in place. During recent ALB eradication 

efforts, greater than 75 percent of the stumps were removed rather than 

being treated with an herbicide. While herbicide application is directly on 

the stump surface, and according to label instructions, damage to nearby 

vegetation could occur from drift or runoff.

b. Environmental Resources

(1) Water

The removal of infested trees near aquatic resources can impact water 

quality. In particular, the movement of soil into aquatic resources (rivers, 

lakes, and other bodies of water) can result in sedimentation, excessive 

nutrients (eutrophication), increased turbidity or cloudiness, and alteration 

of stream flow. In addition, tree removal adjacent to aquatic resources can 

reduce shading, which is important in maintaining water temperature. 

Degradation of water quality due to sedimentation can result in negative 

effects to aquatic organisms through direct or indirect impacts to fish, 

aquatic insects, and crustaceans, such as freshwater mussels and crayfish 

(Richter et al., 1997; Henley et al., 2000). The risk to soil quality and 

aquatic resources from erosion, due to tree removal, can be reduced by the 

implementation of timber BMPs (Aust and Blinn, 2004).

(2) Air

As described in the environmental consequences for the no action 

alternative, the loss of trees to ALB infestation could affect air quality and 

contribute to climate change. The degree to which air quality and climate 

change are affected depends on the human-facilitated contribution of air 

pollutants, as well as the number of trees infested with ALB. 

Trees infested with ALB reach mortality within 10 to 15 years. During the 

declining stage, trees continue to intercept air pollutants and sequester 

CO2; however, stress to these trees decreases their ability to sequester 

carbon dioxide (Bréda et al., 2006). Removal of trees prior to mortality 

64 IV. Environmental Consequences
reduces the interception of air pollutants and sequestration of carbon 

dioxide. Trees release stored carbon during decomposition or burning. 

Under this alternative, the Program removes and chips infested trees. 

Wood chips decompose at a faster rate than intact woody material, 

resulting in a faster release of carbon dioxide (McPherson and Simpson, 

1999). Replacement of trees through succession or planting would restore 

air quality attributes to the area; however, this would occur slowly over 

time and would vary depending on the types of species that may regrow in 

areas. 

The loss of trees through the removal of ALB-infested trees by the 

Program would temporarily affect the local carbon sequestration. For

example, the potential total CO2 release estimate from trees and soil at five 

ALB eradication sites active in 2012 is 20,187 mt (appendix D). These 

levels are below the CEQ reference level of 25,000 mt for all GHGs; other 

GHGs (methane, nitrous oxide, hydro-fluorocarbons, perfluorocarbons, 

and sulfur hexafluoride) were not included in this study. The restoration 

of vegetation and trees reduce the contribution of CO2 to the atmosphere 

from the removal of trees by the Program.

In urban areas, where trees now shade buildings, tree removal under ALB 

eradication would increase energy requirements and emissions of GHGs

from power plants to compensate for increased heating in winter and air 

conditioning in summer. For example, in New York City, trees are 

estimated to reduce energy costs from residential buildings by 

$11.2 million annually based on 2002 energy costs. Trees also provide an 

additional $167,000 in value per year by reducing the amount of carbon 

released by the city’s fossil-fuel based power plants (a net reduction of 

9,100 tons of carbon emissions) (Nowak et al., 2007).

Several U.S. cities have greening programs (e.g., Boston (http://www. 

growbostongreener.org/gbg/) and Baltimore 

(http://www.baltimoretreetrust.org/) aimed at increasing tree cover to 

achieve benefits trees provide, including improved air quality, 

sequestration of carbon, reduced energy consumption, and flooding 

control (Nowak et al., 2007; Nowak et al., 2010). The removal of infested 

trees prior to mortality in urban areas and adjacent forest would negatively 

affect these benefits. However, infested trees weaken over time and 

eventually fail to benefit the urban environment; rather, they may become 

a fall hazard. In addition, leaving infested trees leads to additional tree 

infestations due to ALB spreading resulting in more tree loss.

The combustion of gasoline and diesel fuel in machinery used to remove

and chip trees release air pollutants and GHGs (McPherson and Simpson, 

1999). Estimates of release for these activities are scarce, including data 

IV. Environmental Consequences 65
from ALB Eradication Program activities. Emissions from tree removal 

and chipping activities would have the greatest impact to air quality in 

urban areas where air quality may already be impacted. 

(3) Soil

Soil quality impacts under this alternative (Alternative 2: Removal of 

Infested Trees) would be similar or, in some cases, more significant than 

those described under the no action alternative. Under this alternative 

infested trees would be removed, which could result in physical and 

chemical impacts to soils, especially in areas where soils are vulnerable to 

erosion. The removal of only infested trees without addressing host trees 

nearby at risk of infestation could also allow ALB to continue to spread, 

resulting in additional tree removals in areas where soils may be 

susceptible to erosion. 

c. Ecological Resources

The removal of infested trees would have impacts to ecological resources 

similar to those described under the no action alternative, although at a 

potentially slower rate in the long term. Initially the rate of tree loss under 

this alternative would be greater in the infested areas compared to the no 

action alternative since trees would be removed more quickly than through 

natural loss from ALB. In cases where infested trees are removed, some 

of the impacts previously noted could occur. However, the expansion of 

ALB resulting from not removing high-risk host trees within the known 

dispersal range of ALB would leave those trees vulnerable, and 

infestations would continue to occur, resulting in additional removal of

infested trees. 

Herbicide Use

APHIS uses herbicides when there are limitations to physical removal of

stumps. The limitations include those areas that are inaccessible to 

equipment used for stump grinding, and those areas that are sensitive to 

erosion or compaction.

The Program uses the herbicide triclopyr by spraying or painting the root 

collar area (the sides of the stump) and the outer portion of the cut surface, 

including the cambium (thin layer of generative tissue lying between the 

bark and the wood of a stem), until thoroughly wet, but not to runoff. 

Foliar applications of triclopyr mixed with two other herbicides, imazapyr 

and metsulfuron-methyl, would be applied to sprouting foliage from 

stumps that remain after tree removal to prevent regrowth.

66 IV. Environmental Consequences
Triclopyr triethylamine salt (TEA) toxicity to terrestrial wildlife is 

considered low. Toxicity to avian species is low for triclopyr TEA with 

oral and dietary median lethal toxicity values greater than the highest 

test concentrations tested (EPA, 1998; Durkin, 2003). Chronic toxicity 

to birds is also expected to be low with reproductive toxicity. The no

observable effect levels (NOEL) are 100 and 500 parts per million 

(ppm) for the mallard and bobwhite quail, respectively, when exposed 

to triclopyr acid (EPA, 1998). Available avian toxicity data for 

triclopyr butoxyethyl ester (BEE), another triclopyr product available 

for use by the Program, demonstrates slight toxicity, with median lethal

dose values ranging from 735 to 849 mg/kg for the bobwhite quail

(EPA, 1998). These values are well above any residues that would 

occur due to Program applications. Triclopyr TEA is not toxic to honey 

bees based on acute contact studies (EPA, 1998). Triclopyr TEA does 

exhibit toxicity to some terrestrial plants based on results from seedling 

emergence, germination, and vegetative vigor studies. The primary 

degradation product of triclopyr TEA, triclopyr acid, is similar in 

toxicity to terrestrial nontarget organisms based on the available toxicity 

data. 

TEA toxicity to aquatic organisms is low for fish and aquatic 

invertebrates. Available acute fish toxicity data demonstrates median 

lethal concentrations greater than 100 mg/L for Garlon® 3A and 

technical triclopyr TEA (Wan et al., 1987; EPA, 2014a). Triclopyr TEA 

is not considered toxic to aquatic invertebrates in freshwater and marine 

environments, with toxicity values exceeding 300 mg/L. Chronic 

toxicity to fish and aquatic invertebrates is also low with chronic toxicity 

no observable effects concentration (NOEC) ranging from approximately 

80 mg/L to greater than 100 mg/L, depending on the test organism and 

endpoint. Although Triclopyr BEE may be toxic to aquatic invertebrates

and fish, they will not be exposed to levels that could result in adverse 

effects from applications made by the Program. The primary metabolite 

of triclopyr TEA and BEE, triclopyr acid, is not considered toxic to 

aquatic organisms, based on available toxicity data (EPA, 1998, 2014a).

For foliar treatments, Garlon® 3A is proposed for use as a mixture with 

the active ingredients imazapyr and metsulfuron-methyl. Imazapyr is 

an imidazolinone herbicide while metsulfuron-methyl is a sulfonylurea 

herbicide, with both products used as a mixture with triclopyr in the 

control of woody vegetation. 

The toxicity of imazapyr and metsulfuron-methyl is considered low for

mammals. The formulation containing metsulfuron-methyl, Escort® XP, 

is not considered toxic to mammals via inhalation, dermal, and oral 

exposures. All toxicity values were reported as greater than the highest 

test concentration. In addition, metsulfuron-methyl is not considered to

IV. Environmental Consequences 67
be carcinogenic, nor has it been shown to be a reproductive, teratogenic, 

or developmental hazard (Klotzback and Durkin, 2004). Escort® XP is 

considered a slight eye irritant, but is not considered a skin irritant or 

sensitizer. The other herbicide in the mixture, Arsenal®, containing the

active ingredient imazapyr, has a similar mammalian toxicity profile to 

metsulfuron-methyl, and is considered practically nontoxic in acute 

inhalation, dermal, and oral exposures. Imazapyr is not considered a 

carcinogen or mutagen, and is not known to be a reproductive, 

teratogenic, or developmental hazard (Durkin and Follansbee, 2004).

The toxicity of imazapyr and metsulfuron-methyl is low to all nontarget 

organisms, with the exception of some aquatic and terrestrial plants. 

Neither product is considered toxic to mammals, birds, or terrestrial

invertebrates (Durkin and Follansbee, 2004; Klotzback and Durkin, 2004;

EPA, 2014a). Toxicity to fish and aquatic invertebrates is very low, with 

median lethal acute concentrations typically exceeding 100 mg/L for both 

chemicals (Durkin and Follansbee, 2004; Klotzback and Durkin, 2004;

EPA, 2014a). Chronic toxicity to fish and aquatic invertebrates is also

considered low, based on the available NOECs that were reported from

standardized toxicity studies.

Exposure to terrestrial and aquatic nontarget organisms is expected to be 

minimal from each proposed formulation and mix. Significant drift or 

runoff is not expected as applications are not broadcast applied, but are 

made using either a backpack sprayer to deliver a coarse droplet size, or 

by brushing the material on individual stumps and associated sprouting 

vegetation. The low probability of offsite transport for any of the products

results in very low exposure to most nontarget organisms. The low 

probability of exposure and the favorable available effects data

demonstrate that all products have a very low risk of causing adverse

ecological risk (see appendix E). Risk to nontarget organisms is greatest 

for plants as they are the most sensitive group to each application;

however, the application methods and label directions minimize impacts 

to terrestrial plants, restricting potential harm to those plants that are 

immediately adjacent to treated stumps or sprouts. Exposure in aquatic

systems is not expected to occur at levels that could result in any direct 

impacts to aquatic plants, or at levels that would suggest indirect impacts

to aquatic organisms that depend on aquatic plants as a food source or as

habitat. (Appendix E provides the risk assessment for herbicides the 

Program proposes to use.) 

d. Economic, Social, and Cultural Resources

As described in the environmental consequences section for the no action 

alternative, ALB-host trees are important to the forestry products industry 

and their loss, particularly on forested lands, would result in negative 

68 IV. Environmental Consequences
economic impacts. The Program removes and chips infested trees, making 

them unavailable to the timber and forestry products industry. ALB larvae 

create tunnels or galleries inside the tree, damaging the structural integrity 

of the wood. It is possible that lightly infested trees could have 

salvageable wood for timber and other end-use products; however, the 

Program does not allow the diversion of infested trees from chipping to 

saw mills because of the risk of spreading ALB. 

One maple tree can produce 10 to 60 gallons of sap for maple syrup in one 

season, depending on the tree (including size), weather conditions, length 

of sap season, and the method of collecting sap 

(http://maple.dnr.cornell.edu/index.html). Maple syrup producers can 

absorb a loss of a percentage of maple trees but, depending on the size of 

the producer, there is a threshold where economic loss would shut down 

the business. APHIS does not recommend replacing maple trees with 

ALB-host trees in an area infested with ALB; therefore, replanting would

not be an option for maple producers.

The impact to landowners is similar to those described under the 

environmental consequences for the no action alternative. However, the 

Program will remove infested trees rather than leaving them to die in 

place. In the early stages of infestation, trees can appear healthy and 

continue to provide the aesthetic qualities and other benefits. Trees 

decline and die at different rates, depending on type of tree, its size, the 

population of ALB, exposure to other stressors, and other factors.

Symptoms occur in approximately 3 to 4 years after infestation, and tree 

death can occur in 10 to 15 years, depending on site conditions. The 

Program would remove trees at all stages of infestation. This alternative 

would slow the spread of ALB; however, due to the difficulties in 

identifying infested trees, it is likely that some infested trees would be 

missed and, therefore, ALB would spread.

(1) Human Health

Under this alternative, the overall rate of tree loss from ALB infestation is 

expected to be reduced from the no action alternative because the Program 

removes infested trees, which reduces the ALB population and spread to 

other host trees. However, tree removal activities would initially cause an 

increase in tree loss, compared to the no action alternative where infested 

trees remain in place to die from ALB-infestation. In the short term, tree 

removal activities may result in increased noise levels (from use of 

mechanical equipment and increased traffic), increased stress (from 

decreased property values), increased cooling and heating costs, and other 

localized negative human health consequences from a lack of trees, (as 

discussed in the no action alternative) to the general public living in the 

infested areas. In the long term, the negative human health consequences 

IV. Environmental Consequences 69
could be less than those compared to the no action alternative because the 

overall tree loss is expected to decrease to some degree. 

(2) Herbicide Use

APHIS evaluated the risk to workers and the general public from the 

Program use of the three herbicides (appendix E). Two triclopyr 

formulations, Garlon® 3A (active ingredient is TEA) and Pathfinder® II 

(active ingredient is BEE), for the treatment of stumps were analyzed.

Pathfinder® II is used to treat the bark instead of direct application to cut 

areas of the stem. Minor foliar applications of Garlon® 3A mixed with 

two other herbicides, imazapyr and metsulfuron-methyl, are used to treat 

sprouting foliage from stumps that have been removed as part of the 

eradication program. The applications are made by hand either by 

brushing undiluted material on the stump or directly spraying stumps 

and/or sprouting foliage using a backpack sprayer. The TEA formulation 

can cause significant eye irritation, but has low acute inhalation and 

dermal toxicity. Acute oral median lethal concentrations range from 

approximately 600 to 1,000 mg/kg, suggesting low to moderate toxicity 

(Durkin, 2003).

Long-term toxicity studies have shown that triclopyr TEA is not a 

carcinogen or mutagen, and that toxicity in developmental and 

reproductive studies primarily occurs at high doses, and at levels that are 

also maternally toxic (EPA, 1998). The concentrations at which these 

effects have been reported would not occur under normal program uses.

The other proposed BEE formulation, Pathfinder® II, can cause slight 

temporary eye irritation during application, and some skin irritation under 

prolonged exposure. Acute oral median lethal concentrations are 

1,000 mg/kg, with acute inhalation and dermal toxicity median lethality 

values greater than the highest test concentration, suggesting low acute 

mammalian toxicity under various exposure pathways. Triclopyr BEE is 

not considered carcinogenic or mutagenic and, in cases where 

developmental and reproductive studies demonstrate effects, doses were at 

levels considered maternally toxic. The concentrations at which these 

effects have been reported would not occur under normal program uses.

TEA breaks down in soil (~12 days) to triclopyr acid, and to a lesser 

extent, triethanolamine. Triclopyr BEE has low water solubility, and 

adsorbs more strongly to soil when compared to the amine. Triclopyr 

BEE also breaks down quickly to triclopyr acid in soil and water, with 

hydrolysis half-lives of less than 1 day. Imazapyr degradation and 

dissipation half-lives are variable, ranging from approximately 25 days to 

greater than 300 days. Metsulfuron-methyl half-lives in soil range from 

17 to 180 days. The use of these herbicides may negatively affect 

70 IV. Environmental Consequences
sensitive individuals or those who inadvertently become exposed; 

however, these herbicides are relatively short lived in the environment so 

any health effects from herbicide use are likely to be temporary.

The human health risk assessment results show that using triclopyr, or 

using triclopyr and mixing it with imazapyr and metsulfuron-methyl to 

control ALB populations should pose minimal risks to human health for 

workers and the general public (appendix E).

In addition, notification to landowners also occurs in the case of any 

chemical treatments that may be used to kill stumps (herbicides), as well 

as other label risk reduction requirements for herbicide use that are 

designed to protect workers, the general public, and the environment. 

a. Forest Resources

Host trees within a 1⁄2-mile radius of an infested tree are at risk of ALB 

infestation because they are within the dispersal range of the beetle. 

Under the full host removal alternative, removal by the Program of both 

infested trees and high-risk host trees would occur. Depending on the 

density of host trees in the quarantine area, this will likely translate to the 

removal of a larger population of trees compared to the no action 

alternative and two of the eradication alternatives. The intent is to protect 

urban and rural forests from ALB through the removal of host trees 

potentially infested with ALB but not at detectable levels. 

The impacts to forestry resources, as described in alternative 2, could also 

occur under this alternative. Trees infested with ALB typically die within 

10 to 15 years. Full host removal by the Program prematurely eliminates 

the ecological services the trees provide. Host trees provide habitats and

food for wildlife, and contribute to nutrient and water cycles. The longterm benefits of full host removal in a quarantine area include the 

reduction in the beetle’s spread rate and eradication of the beetle.

Removal of host trees classified as invasive in the United States would be 

beneficial. For example, several Northeastern States designate the 

Norway maple as an invasive species.

b. Environmental Resources

(1) Water

Impacts to water quality from the selection of alternative 3 would be 

increased when compared to alternative 2. The removal of infested trees 

and high-risk host trees would result in soil sediment runoff to aquatic 

areas. Current water quality data for rivers and streams in the 

3. Alternative 3:

Full Host 

Removal

IV. Environmental Consequences 71
United States lists sediments as the second leading cause of impairment 

under Section 303(d) of the CWA (EPA, 2014c). Sediments are the ninth 

leading cause of impairment in lakes, reservoirs, and ponds. The source of 

sediments causing impairment in waterways varies; however, silviculturerelated activities, such as harvesting and forest road construction, are 

contributing factors. These impacts would be more likely in forested areas 

where large numbers of trees may be removed as a result of an ALB 

infestation. Replanting vegetation and following silviculture BMPs will

protect soils vulnerable to erosion, reducing potential for impacts to water 

quality. 

(2) Air

Under this alternative, the potential removal of a greater number of trees 

could cause greater impact to air resources compared to those described in 

Alternative 2—Removal of Infested Trees. Loss of all host-tree species 

across the contiguous United States is estimated to release 13.9 million mt

of CO2 to the atmosphere (appendix D). This large pulse of CO2 to the 

atmosphere is unlikely as ALB spreads slowly, trees become infested at 

different times, and trees die at different rates. Large urban and forested 

areas under quarantine with a high density of ALB-host trees would see 

impacts on the local air quality. 

Forest areas are typically a mixture of tree species. For example, in the 

Northeastern United States, forests are typically a mixture of hardwood

and hardwood-conifer (Shifley et al., 2012); full host removal would not

result in complete deforestation of an area. Emissions from tree removal 

and chipping activities could result in some localized impacts to air 

quality, but these would be reduced over time as eradication efforts are 

implemented. 

(3) Soil

This alternative would result in potentially greater impacts to soil quality,

compared to the other eradication alternatives, because both infested trees 

and high-risk host trees would be removed. Impacts to soil would be 

greatest where large numbers of trees are removed from a concentrated 

area. 

Changes in soil temperature and moisture, as well as soil erosion and loss 

of nutrients in areas, can impact the ability of a forest to regenerate

(Ballard, 2000). These impacts are more prevalent in cases where clearcutting is being used for forest harvesting; however, that type of removal 

is not likely to occur in the Program because other non-ALB-host trees 

would be left standing.

72 IV. Environmental Consequences
Compaction from the use of heavy equipment may result in increased soil 

bulk density values that may limit regrowth of vegetation in areas where 

trees are removed. These physical impacts to soil may result in increased 

erosion of soil from wind and rain, both during and after tree removal. 

Seeding areas with grass or other vegetation reduces these types of soil 

quality impacts. 

c. Ecological Resources

Overall impacts to ecological resources, under alternative 3, are expected 

to be less than those described under the no action alternative and 

alternative 2 because of the prevention of ALB dispersal to non-infested 

areas within the United States. Impacts on a local level may be more 

significant to ecological resources because removal of infested and highrisk host trees may result in some fragmentation, as well as a reduction in

tree density within riparian zones. While these impacts would be more 

localized, compared to the loss of trees resulting from the no action 

alternative, the impacts would be more immediate as trees would be 

removed at a more rapid rate than if they were lost to ALB. The extent of 

ecological impacts would be dependent upon the size of the infestation 

and the predominance of ALB-host trees in natural and urban areas. The 

density of host trees will likely be greater in forest areas than urban 

settings, potentially causing greater impacts to ecological resources in 

forest areas. 

d. Economic, Social, and Cultural Resources

Full host tree removal would result in the removal of more trees within the 

quarantine area compared to the other three eradication alternatives. The 

extent of the impact depends on the density of host trees within the area 

and the intended use of the host trees. Significant impacts could occur if a 

quarantine area overlaps with a woodlot, forest, tree plantation, maple 

syrup production area, or other commercial forestry area dependent upon 

hardwood trees that are hosts to ALB. 

Urban areas predominantly planted with ALB-host trees would see a 

reduction in tree cover. This may result in an initial reduction in aesthetic 

qualities of the landscape, as well as the ecosystem services trees provide; 

this includes reduction in water and sediment runoff, interception of air 

pollutants, and buffering from solar radiation and wind. 

Restoration of areas through the planting or natural regrowth of non-host 

trees and other vegetation may eventually lead toward recovery of 

resources. Suppression in the tourism industry may occur if a high 

proportion of the ecological resource (e.g., park, community, etc.) falls 

within the quarantine area. Full host removal is expected to have less of 

IV. Environmental Consequences 73
an economic impact compared to the no action alternative because this 

alternative slows the spread of ALB and leads to eradication. Compared 

to Alternative 2—Removal of Infested Trees, Alternative 3—Full Host 

Removal is expected to produce greater short-term economic impacts 

because of the potential removal of more host trees. However, in the longterm, it is expected that impacts would be reduced because of the 

protection of forest resources. 

Human Health

Alternative 3 would result in increased efficacy to eradicate ALB, and 

prevent its spread to new areas. In the short term, tree loss would occur

from removal of infested and surrounding host trees. These removals 

could result in localized negative human impacts related to tree loss, such 

as increased stress, reduced air quality, and so on, as discussed in the no 

action alternative. However, in the long term, the rate and spread of tree 

loss due to ALB would be reduced, minimizing human health related 

impacts. 

The potential for human exposure and risk to herbicide use is the greatest 

under this alternative because more trees are being removed and herbicide 

use would be expected to increase. Human health risks are still expected 

to be low based on the herbicide risk assessment included in appendix E of 

this EIS. In some cases, stumps may be left to allow for regrowth in areas 

where ALB reinfestation would not occur. When stump treatment is 

needed, grinding is the preferred method over herbicide treatments; 

therefore, while there would be an increase in herbicide use, it would not 

necessarily be proportional to the increase in the number of trees removed. 

a. Forest Resources

Under this alternative, the Program removes host trees infested with ALB, 

and treats the high-risk host trees located within a 1⁄2-mile radius of 

infested trees with the insecticide imidacloprid. APHIS uses the 

insecticide imidacloprid through trunk or soil injections to protect trees 

from ALB infestation. The Program applies insecticide treatments in the 

fall, spring, and early summer prior to and during the adult emergence 

period. The impact to forestry resources from this alternative include the 

impacts described under forestry resources for Alternative 2: Removal of 

Infested Trees. 

In addition to those impacts, the treatment of high-risk host trees with 

imidacloprid within a 1⁄2-mile radius of infested trees may affect beneficial 

insects (e.g., honey bees) associated with host trees. Research is ongoing 

to understand these interactions and their impacts on tree health and 

reproduction. Research indicates imidacloprid and the application 

4. Alternative 4:

Infested Tree 

Removals 

and 

Insecticide 

Treatment of 

High-Risk 

Host Trees

74 IV. Environmental Consequences
methods do not affect tree growth. Treatment of high-risk host trees with 

imidacloprid may protect these trees from ALB infestation, and prevent 

their removal by the Program. Treatment helps preserve high-risk host 

trees in the quarantine area and the ecosystem services they impart. 

b. Environmental Resources

(1) Water

The removal of infested trees under this alternative has similar water 

quality impacts as Alternative 2—Removal of Infested Trees. Under this 

alternative, insecticide treatment would slow the spread of ALB, however,

it will not stop the spread as treatment does not provide 100 percent

protection to all trees. In comparison to Alternative 3—Full Host 

Removal, we expect this alternative to have less of a short-term impact to 

water quality in regards to host tree removal because the Program would 

remove fewer trees, at least initially, under this alternative. 

Alternative 4 would have the greatest potential for imidacloprid to move 

into surface or ground water) because chemical treatment is the only 

option available for high-risk host trees. Imidacloprid exhibits physical 

and chemical properties that suggest it could contaminate surface and 

ground water. Detections in ground water have occurred in various parts 

of the United States, including States where ALB is present. Solubility 

and a lack of affinity for binding to soil or sediment suggest that 

imidacloprid could move offsite through runoff or leaching (appendix F).

The ability to leach into ground water would depend on site-specific 

conditions, such as soil type and depth to the water table. However, label 

restrictions regarding applications near surface water and other 

information regarding ground water reduces the potential for water 

contamination. In addition, the preferred use of tree injections of 

imidacloprid by the Program further reduces the possibility of impacts to 

water quality when compared to soil injection. 

APHIS collected water samples as part of its monitoring effort to 

determine the potential for imidacloprid to move to surface and ground 

water from Program applications. (The data is available in appendix F.) 

The imidacloprid level in a majority of the water samples is below 

detection in surface and ground water, or below levels that would impact 

human health or the environment. However, detection of imidacloprid in 

some water samples is above the level the Program expects from their 

applications. Due to the widespread use of imidacloprid for other uses, 

especially home and garden, it is difficult to attribute detections to 

program applications in urban areas where a majority of program 

treatments have taken place. The State of New York, after finding 

IV. Environmental Consequences 75
imidacloprid in water samples from all uses, restricts the application of 

imidacloprid to trunk injection. 

(2) Air

The impacts on air quality from the removal of infested trees (as described 

in Alternative 2—Removal of Infested Trees) are the same for this 

alternative. Treatment of ALB-host trees with imidacloprid usually occurs 

through trunk injection, however, sometimes through soil injection. The 

trunk injection method involves injecting imidacloprid directly into the 

tree trunk; this is unlikely to affect air quality due to minimal exposure of 

the insecticide to the ambient air. A minor amount of the insecticide 

volatilizes during the soil injection until full adsorption into the soil and 

uptake by the plant roots occurs. Drift is not expected to impact air 

quality because both application methods would not have any associated 

drift. The chemical and physical properties for imidacloprid suggest that 

there is a low probability of imidacloprid volatilizing into the atmosphere 

and impacting air quality (see appendix F).

(3) Soil

Physical impacts to soil from alternative 4 would be expected to be less 

than those described in alternative 3. Tree removal would not occur for 

high-risk host trees reducing the potential for soil disturbance that could 

occur during removal. There is the potential for impacts to soil as a result 

from imidacloprid treatments of high-risk host trees. Impacts to soil 

quality would be greatest for soil injections compared to tree injections. 

Sensitive soil terrestrial invertebrates would be impacted in the immediate 

area of treatment in the case of soil injection applications; however, soil 

injections rarely occur, and tree injections would minimize these types of 

impacts. Imidacloprid negatively affects earthworms in soil at 

concentrations that have been observed in previous ALB eradication 

efforts using soil injections; however, reported levels do not appear to 

cause long-term impacts to soil microbes (appendix F; (Tu, 1995;

Kreutzweiser et al., 2008a)).

c. Ecological Resources

The impacts to ecological resources, under alternative 4, is expected to be 

less than those described under Alternative 1—No Action Alternative and 

Alternative 2—Removal of Infested Trees because of the prevention of 

ALB dispersal to non-infested trees. Impacts to ecological resources from 

fragmentation and loss of trees in riparian areas would be less than 

alternative 3 because ALB high-risk host trees would receive an 

insecticide treatment rather than being removed. Under this alternative, 

76 IV. Environmental Consequences
ecological impacts from tree removal would be reduced; however, there is 

the potential for impacts from the use of the insecticide, imidacloprid, to 

these same resources that would not occur under alternatives 1–3. These 

impacts are summarized in the following section with a more detailed 

analysis in appendix F.

There may be circumstances where imidacloprid use is not practical and, 

under this alternative, the inability to remove high-risk host trees would 

allow for the spread of ALB to other trees. In addition, imidacloprid 

efficacy is variable as a prophylactic treatment for ALB (Poland et al., 

2006). Site-specific conditions, regarding tree health and other factors, 

can impact the uptake and distribution of imidacloprid in trees, allowing 

ALB to survive even within imidacloprid-treated trees. In these situations, 

ALB would be able to spread, with the possibility of additional infested 

tree removal and insecticide treatments, increasing the risk to terrestrial 

and aquatic ecological resources. 

Insecticide/Herbicide Use

Imidacloprid has low to moderate acute toxicity to wild mammals, based 

on the available toxicity data. Imidacloprid is considered toxic to birds 

with acute oral median toxicity values ranging from 25 to 283 mg/kg 

(Anatra-Cordone and Durkin, 2005; EPA, 2014c). Reproduction studies 

using test species to support pesticide registration (e.g., the mallard and 

bobwhite quail) have shown NOECs of 125 ppm for both species. The 

application method and the available effects data indicate low exposure 

and risk to terrestrial vertebrates (e.g., birds and mammals) (appendix F). 

Applications using trunk and soil injection remove the risk of exposure 

from drift or runoff. There is the possibility of imidacloprid exposure to 

mammals and birds that may feed on insects or vegetation from treated 

trees. APHIS measured imidacloprid leaf and twig residue values, and

demonstrated that most birds and mammals would have to consume

several times their daily intake to reach an adverse effect. The risk to 

terrestrial vertebrates consuming insect prey with residues of imidacloprid 

is unknown; however, as these prey do not forage exclusively on treated 

trees and residue levels are not enough to kill them, the risk to predators is 

likely low. Imidacloprid is also specific to certain groups of insects, and 

would not affect all insects that are present on treated trees.

Technical and formulated imidacloprid is acutely toxic to honey bees, and 

other related bee species, at exposures of 3.7 to 230 nanograms (ng)/bee 

by oral and contact exposure (Schmuck et al., 2001; Tasei, 2002; AnatraCordone and Durkin, 2005; EPA, 2014a). Acute sublethal effects in 

laboratory studies show NOECs at less than 1 ng/bee (Anatra-Cordone and 

Durkin, 2005). Imidacloprid metabolite toxicity to honey bees is variable 

with some of the metabolites having equal toxicity to imidacloprid, while

IV. Environmental Consequences 77
other metabolites are practically nontoxic (Anatra-Cordone and Durkin, 

2005). Several studies have been conducted to determine potential 

sublethal effects in laboratory and field situations. Studies to assess the 

effects of imidacloprid on homing behavior, colony development, foraging 

activity, reproduction, wax/comb production, and colony health, as well as

other endpoints, generally reveal effects at levels above those measured in 

nectar and pollen in the field from agricultural crops under various

application methods (appendix F). 

Impacts to honey bees from sublethal exposure to imidacloprid in the 

presence of other stressors have also been evaluated in laboratory studies. 

These studies suggest that pesticides, such as imidacloprid, in combination 

with pathogens may impact colony health and immune function in honey 

bees (Alaux et al., 2010; Vidau et al., 2011; Pettis et al., 2012). Due to the

uncertainty of the risk to honey bees from the proposed treatments in this

program, APHIS provided funding for a multiyear study to determine the 

potential for exposure and effects to honey bees from the proposed 

treatments (Johnson, 2012). Results from that work suggest that these

types of applications do not adversely impact honey bees and their hives, 

and that imidacloprid residue pollen levels collected from maple trees is 

low, with an average concentration of 5.3 micrograms (μg)/kg from tree 

injection applications, and 0.28 μg/kg from soil injections of imidacloprid.

Residues of imidacloprid and six associated metabolites were reported as 

below detection in nectar samples. 

Imidacloprid exposure to terrestrial invertebrates from the ALB 

Eradication Program, especially honey bees, is not expected to result in 

significant risk to pollinators. Pollinator exposure to imidacloprid is

reduced because only treated trees and their associated flowers and pollen 

could have residues, while other flowering plants that have not been

treated would not contain residues. Exposure and risk would increase in 

cases where large numbers of trees are treated over large areas prior to 

flowering, and in cases where only flowers from treated trees are the 

primary nectar source. This may occur in the Northeastern United States 

where maple trees bloom prior to many other flowering plants. 

Applications of imidacloprid, particularly via soil injection, could expose 

soil-dwelling invertebrates sensitive to the insecticide; however, 

environmental fate data indicate the effects are transient (Anatra-Cordone 

and Durkin, 2005). In cases where imidacloprid is tree-injected, there

would be reduced exposure and risk to soil-dwelling terrestrial

invertebrates; exposure would occur primarily from leaves that drop from

treated trees. These risks would be proportional to the number of treated

trees in a given area.

78 IV. Environmental Consequences
Imidacloprid has low toxicity to aquatic organisms including fish, 

amphibians, and some aquatic invertebrates. Acute toxicity to fish and 

amphibians is low, with acute median lethal concentrations typically 

exceeding 100 mg/L (Anatra-Cordone and Durkin, 2005; EPA, 2014a).

Chronic toxicity to fish is in the low ppm depending on the test species 

and endpoint. Aquatic invertebrates are more sensitive than fish to 

imidacloprid (Anatra-Cordone and Durkin, 2005; EPA, 2014a)

(appendix F).

Imidacloprid exposure in aquatic environments and risk to aquatic biota is

low (appendix F). The method of application eliminates the potential for 

drift and, in the case of tree injections, eliminates the probability of offsite 

runoff. Another potential pathway of exposure to aquatic organisms is 

imidacloprid residues in leaf litter from treated trees. Aquatic 

invertebrates feeding on leaf litter containing imidicloprid residues have 

measurable sublethal impacts, as well as impacts on decomposition rates 

(Kreutzweiser et al., 2007; Kreutzweiser et al., 2008a, b; Kreutzweiser et 

al., 2009). Mortality to some leaf-shredding insects occurred when they 

were intentionally overdosed at levels higher than they would encounter at 

typical field applications (Kreutzweiser et al., 2007; Kreutzweiser et al., 

2009). Not all plant material available to aquatic decomposers will 

contain imidacloprid as ALB-host trees are part of a greater ecosystem 

that will contain other plant and organic material. Exposure and risk to

aquatic organisms will increase in situations where large numbers of trees 

may be treated within a watershed. The risk to aquatic organisms from

this exposure can be reduced by not treating trees, or treating a small 

number of trees, and avoiding treatments close to surface water. 

There is a potential for subsurface transport of imidacloprid to aquatic

habitats for applications made directly into soil. This exposure will be 

minimized by only making applications where the ground water table is

not in proximity to the zone of injection, and avoiding soils that have a 

high-leaching potential. Conservative estimates of potential aquatic 

residues in static, shallow bodies of water from soil injections, based on 

maximum label rates, demonstrate values that are not expected to have 

indirect or direct impacts to aquatic biota (appendix F). Actual aquatic

residues will be below levels that could harm aquatic biota due to the low 

chance of moving offsite, which is a result of the method of application 

and environmental fate of imidacloprid.

The potential impacts to ecological resources from herbicide use would be 

low and less than those described under alternatives 2 and 3 (appendix E)

because fewer trees would be cut down. Expansion of infested areas or 

new infestations would occur at a slower rate under alternative 4, when 

compared to alternative 2. This would result in less herbicide use in an 

infested area, and in new introductions reducing the impacts to aquatic and 

IV. Environmental Consequences 79
terrestrial ecological resources. Herbicide use would be greater under 

alternative 3, compared to alternative 4, because more trees would be 

removed under alternative 3 (both infested trees and host trees within a 1⁄2-

mile radius). 

d. Economic, Social, and Cultural Resources

The economic impacts, under alternative 4, would be less than those 

described under alternatives 1 and 2. In relation to preventing the spread 

of ALB, the economic impacts may be similar to those described under 

alternative 3 when imidacloprid treatments are successful in serving as a 

prophylactic treatment of high-risk host trees. However, due to the 

variability in imidacloprid uptake by trees and other site-specific 

conditions (e.g., general tree health), insecticide treatments may not 

provide the level of protection that removal of high-risk host trees would 

provide. In cases where imidacloprid treatments cannot be successfully 

used for high-risk host trees, the economic impacts would be greater than 

those under alternative 3 because ALB would be able to expand its range 

and infest new areas. In addition, the cost of multiple insecticide 

treatments to a tree is greater than the costs of removal. 

Potential economic losses specific to the use of imidacloprid could occur 

for the maple syrup industry because imidacloprid label restrictions would 

render treated trees unusable for syrup production. Imidacloprid is a 

systemic insecticide, and concentrations of the insecticide will be present 

in the tree sap. The economic impact to maple syrup producers will be 

dependent upon the proportion of their maple trees removed from 

production through either tree removal or treatment with imidacloprid. 

Similarly, nursery tree producers would incur costs by treating host trees 

with imidacloprid to protect their inventory, and to meet regulatory 

requirements for shipping trees outside the quarantine boundary. Sales of 

nursery trees that are hosts to ALB, regardless of treatment with 

imidacloprid, may drop as buyers select trees that are not hosts to ALB. 

As discussed in alternative 2, the removal of infested trees from public and 

private lands may result in economic, social, and cultural impacts. The 

option to be able to treat trees with imidacloprid will be based on an 

evaluation, by the Program, of site-specific conditions for a given 

infestation. 

The forestry and tourism industries, as well as public and private 

landowners located near an ALB quarantine area, will gain protection 

from ALB through the confinement of pest populations, and eradication 

through removal of infested host trees and treatment of host trees in 

proximity to infested trees. These benefits will be realized in situations 

80 IV. Environmental Consequences
where imidacloprid can be used to successfully provide protection to highrisk host trees. 

(1) Human Health

Under alternative 4, in the short term, tree loss would occur from removal 

of infested host trees. Initially, the number of trees lost from removal 

activities is similar to alternative 2 as only infested host trees would be 

removed in this alternative. Prophylactic treatments with imidicloprid 

would protect some high-risk host trees and may result in an overall 

decrease in the removal of infested trees compared to alternative 2. 

APHIS expects the removal of fewer trees under alternative 4 compared to 

alternative 3—Full Host Removal. Some localized negative human health 

consequences from tree loss are expected as discussed in alternative 2. 

This alternative is less effective than alternative 3 because insecticide 

treatment is unlikely to stop the spread of ALB resulting in additional tree 

loss in the future. 

(2) Insecticide/Herbicide Use

APHIS uses the insecticide imidacloprid through trunk or soil injections to 

protect trees from ALB infestation. For trunk injections, applicators drill 

holes around the trunk, 2 to 6 inches above the soil-wood line. For soil 

injection, applicators inject imidacloprid, at a minimum of four injection 

sites spaced evenly around the base of the tree. Application occurs under 

the soil around the base of the tree, normally no more than 12 inches from 

the base. No material may puddle or run offsite. In addition, APHIS uses 

herbicides to treat stumps and roots of felled trees, as described in 

alternative 2.

APHIS prepared a risk assessment to evaluate the risks for workers and 

the general public associated with the use of imidacloprid applications 

using trunk and soil injections (appendix F). Several formulations are 

available for this particular application. Technical and formulated 

imidacloprid (Merit® 2F) has low to moderate acute oral mammalian 

toxicity, with median toxicity values ranging from 400 to greater than 

4,000 mg/kg. Acute lethal median toxicity values are typically greater 

than 2,000 mg/kg and 5.3 mg/L for dermal and inhalation exposures, 

respectively. Chronic oral exposure toxicity studies in rat, dog, and mouse 

showed that the rat was the most sensitive test species with a NOEL of 

5.7 mg/kg/day. The EPA acute and chronic reference doses (RfD) are

0.14 mg/kg/day and 0.057 mg/kd/day, respectively.

Imidacloprid is a neurotoxic insecticide, based on its mode of action.

Available literature for imidacloprid and associated metabolites suggest a 

lack of carcinogenic, mutagenic, or genotoxic effects at relevant doses. 

IV. Environmental Consequences 81
Developmental, immune, and endocrine-related effects were observed in 

some mammal studies; however, these effects occurred at doses that 

would not be expected to occur under program use.

Exposure to imidacloprid is greatest for applicators, but is reduced by 

following label directions regarding personal protective equipment (PPE).

The human health risk assessment quantified risks for occupational worker 

exposure and general public exposure using a child soil ingestion (pica) 

scenario. Results from that assessment show that imidacloprid used to 

control ALB poses minimal risk to human health under both exposure 

scenarios. The human health risk assessment (included in appendix F)

provides details on toxicity, exposure, and risk associated with 

imidacloprid. 

Herbicide risks to human health would be similar to those described under 

alternative 2. Notification to landowners also occurs in the case of any 

chemical treatments that may be used to kill stumps (herbicides) or treat 

high-risk host trees for ALB (insecticide). In addition to the notification

process, there are other risk reduction requirements for pesticide use that 

are designed to protect workers, as well as the general public and the 

environment. 

Another potential exposure pathway for the public is the use of 

imidacloprid-treated trees for firewood. The levels of imidacloprid in 

treated trees that could be used as firewood is expected to be low because 

the insecticide moves to the leaves, and smaller, actively growing 

branches in the tree where insect feeding is greatest; these parts of the tree 

would not typically be used as firewood. In cases where trees are treated, 

their removal would not be expected to occur in the same growing season 

as treatment, allowing degradation of imidacloprid. In addition, trees 

harvested for firewood are usually allowed to dry before they are used as 

fuel, which would allow for additional degradation of imidacloprid. The

rapid combustion of wood at high temperatures, as can occur in a fireplace,

results in rapid degradation of other types of pesticides; residues are more 

likely under slow combustion and temperatures less than 1112 o

F (600 oC) 

(McMahon et al., 1985; Bush et al., 1987a; Bush et al., 1987b).

Imidacloprid would be expected to degrade at temperatures similar to 

those that would occur from burning firewood, based on its measured 

thermal decomposition temperature, which is below 932 o

F (500 oC). 

Potential thermal degradation products from the use of the imidacloprid 

formulations that could be used in the Program include hydrogen cyanide, 

carbon monoxide, and oxides of nitrogen and carbon. Concentrations of 

these degradation products would be very low due to the expected 

concentrations of imidacloprid in firewood, and potential temperatures 

that could occur in burning firewood. 

82 IV. Environmental Consequences
a. Forest Resources

The impacts of the preferred alternative on forestry resources will be 

similar to those impacts described in alternatives 3 and 4. Under the 

preferred alternative, the Program may either remove high-risk host trees 

or treat high-risk host trees with imidacloprid. An integrated approach 

alternative allows for the adaptation of eradication methods to suit sitespecific needs and resources. In the long term, adverse impacts to forest 

resources would be greatest under Alternative 1—No action Alternative 

and Alternative 2—Removal of Infested Trees when compared to the 

preferred alternative, the integrated approach. Alternative 1 is not an 

eradication program and ALB would continue to spread under 

alternative 2.

b. Environmental Resources

(1) Water

Impacts to water quality (described for the previous alternatives, other 

than the no action alternative), would apply to the preferred alternative as 

they require some level of tree removal that can result in impacts to water 

quality. These impacts will be greatest in watersheds that have soils that 

are vulnerable to erosion and large numbers of host trees in proximity to 

water. However, the short-term impacts to water quality would be 

reduced under the preferred alternative when compared to the

implementation of the exclusive use of tree removal or insecticide 

treatment of high-risk host trees. 

Flexibility in addressing high-risk host trees would allow the Program to 

implement measures with the greatest chance of success based upon sitespecific conditions and resources. Potential long-term impacts to water 

quality would be reduced as ALB eradication efforts would have a greater 

probability of success, and prevent the spread and introduction of ALB to 

other watersheds in the United States where host trees are present. 

(2) Air

The impacts to air quality (described for the previous alternatives, other 

than the no action alternative) would apply to the preferred alternative, as 

it requires some level of tree removal, which can affect air quality.

However, the impacts for the preferred alternative would be reduced 

compared to those alternatives because neither imidacloprid treatment nor 

removal of high-risk hosts would be used exclusively. Impacts to air 

quality from tree removal activities would be more localized when 

compared to full host tree removal. Air quality impacts from the use of 

the herbicides, or the insecticide imidacloprid, are not anticipated based on 

5. Alternative 5:

Integrated 

Approach 

(Preferred 

Alternative)

IV. Environmental Consequences 83
their use pattern and the low probability of any chemical volatilizing into 

the atmosphere.

(3) Soil

The impacts to soil would be similar to those described for alternatives 3 

and 4, Full Host Removal and Insecticide Treatment of High-Risk Host 

Trees. Both Alternative 1—No Action and 2—Removal of Infested Trees 

would allow ALB to continue to expand its distribution within the 

United States, with impacts to soil quality dependent upon the importance 

of ALB-host species in soil nutrient cycling. The potential for soil quality 

impacts would increase with the removal of infested trees under 

alternatives 2 through 4; however, impacts under the preferred alternative 

would be less as there would be an option for tree removal of ALB highrisk host trees or insecticide treatment. Insecticide treatment can impact 

soil quality for those soil fauna that are sensitive to imidacloprid; 

nonetheless, these impacts would be more localized than tree removal 

activities that can result in the physical disruption of soil through the use 

of heavy equipment. 

c. Ecological Resources

Environmental impacts from the selection of the preferred alternative may

result in long-term impacts that are less than those described under the no 

action alternative and the other eradication alternatives. The 

implementation of alternative 5 has been shown to be a successful 

eradication program strategy in site-specific infestations. Risks to 

ecological resources would be localized to the areas of infestation similar 

to alternatives 3 and 4; however, in the case of high-risk host trees, the 

Program would have the flexibility to select the treatment option that best 

fits site-specific conditions. There would be potential risks related to 

removal of trees, as described under alternative 3, and insecticide 

treatment, described under alternative 4 however, flexibility to select 

either method would reduce the risk when compared to the exclusive use 

of either eradication method.

d. Economic, Social, and Cultural Resources

Selection of the preferred alternative may have economic, social, and 

cultural impacts similar to those described for alternatives 3 and 4. These 

impacts would be reduced under the preferred alternative because there is 

flexibility in how high-risk host trees would be treated. Alternative 1 and 

alternative 2 would have the greatest potential impacts because neither 

approach eradicates ALB. 

84 IV. Environmental Consequences
Human Health

Under alternative 5, the rate of tree loss is expected to be reduced the most 

compared to the other alternatives. In the short term, tree loss may occur 

from removal of infested and some surrounding host trees. The amount of 

tree loss from the removal activities would be more than alternative 2 and 

4 but less than alternative 3. Localized negative human health 

consequences from tree loss (e.g., increased stress and reduced air quality 

as discussed in the no action alternative) are expected in the affected areas 

where ALB infested and high-risk host trees are removed. 

This alternative is expected to eradicate ALB resulting in less tree loss in 

the long term. Eradication of ALB would allow all the benefits of trees to

continue in broader areas, and the negative consequences from a lack of 

trees can be avoided. Specifically, shading and improved air quality 

would continue to be available for people living in and travelling through 

affected areas. Trees would continue to provide opportunities for stress 

reduction and beautify the landscape.

e. Adaptive Management Approach

The adaptive management approach evaluates future pesticide use for 

similar or less impacts than those described for the pesticides in each of 

the alternatives discussed in this EIS. This includes any changes in 

herbicide or insecticide use that could occur in the future as the Program 

evaluates new chemical treatment options. The use of the adaptive 

management approach is only in cases where a human health and 

ecological risk assessment demonstrates that proposed pesticides would 

have equal or less risk to human health and the environment, in 

comparison to the pesticides currently used by the program. The criteria 

for this approach ensures that the potential pesticide-related impacts to the 

various resources discussed in this EIS are similar, or less, than those 

associated with any new pesticide use proposed in the future. 

Cumulative impacts are those impacts on the environment that result from 

the incremental impact of an action when added to other past, present, and 

reasonably foreseeable future actions, regardless of what agency (Federal 

or non-Federal) or person undertakes such actions. Cumulative impacts 

can result from individually minor, but collectively significant actions

taking place over time. The potential for cumulative impacts in the ALB 

Eradication Program will vary across the United States due to the various 

site-specific conditions where an infestation may occur. 

The cumulative impacts discussion in this EIS is meant to be general 

because the baseline environmental conditions vary between urban and 

forested areas, and other site-specific conditions that may occur where 

6. Cumulative 

Impacts

IV. Environmental Consequences 85
ALB-host trees are present. Site-specific EAs may incorporate this 

information to better characterize the potential cumulative impacts related 

to an ALB Eradication Program.

For the Program, the cumulative impacts are primarily associated with the 

loss of trees, and the proposed use of an insecticide and herbicides. The 

severity and intensity of tree loss varies under the different alternatives, as 

well as the dominance of ALB-host trees in a given area. 

Cumulative impacts related to forest resources would be expected under 

those alternatives where ALB is likely to spread and infest new areas. 

Cumulative impacts to forest resources would also be expected during 

successful eradication efforts; however, those impacts would be more 

localized and short term compared to instances where ALB is allowed to 

spread. The effects of natural and manmade stressors to forests (e.g., 

timber harvests, acid rain, climate change, and other pests and diseases) 

can be additive or synergistic, that is, the effects of all of the stressors 

together become greater than the individual stressors alone (Cox, 1999;

Logan et al., 2003). The effect of these other stressors added to the impact 

of an ALB infestation could increase the severity of an ALB outbreak. An 

example of this type of cumulative impact is evident with the decline of 

oaks in the Ozark forests in the Central United States. A native 

cerambycid beetle, the red oak borer (Enaphaledes rufulus) was not a 

major pest of oak, but is now considered a major contributor to oak 

decline in the area due to other factors that predispose the trees to 

infestations at higher levels than previously recorded (Coulson and 

Stephen, 2006).

The loss of ALB-host trees may have cumulative impacts by increasing 

the ability of invasive plants to establish in areas where canopy gaps 

occur, or other areas where host trees are lost. These types of 

introductions have been noted in disturbed forested areas, and may impact 

natural plant succession, as well as nutrient cycling (Woods, 1997;

Meiners et al., 2002).

Currently, FS is addressing approximately 70 invasive species (plants and 

insects) in areas where ALB-host trees are present. The impact from the 

loss of ALB-host trees could result in cumulative impacts that would 

benefit the establishment of many of these species. These impacts would 

be more widespread under the no action alternative (1) and alternative 2 

because ALB would be able to establish and spread to other areas of the 

United States. These types of cumulative impacts may also occur under 

alternatives 3 through 5 because tree removal would occur, however, for 

the alternatives that result in eradication, the potential cumulative impacts 

would be reduced. 

86 IV. Environmental Consequences
Under the no action alternative, it is possible other State and local agencies 

or tribes will implement an eradication program without involvement from 

APHIS. Given the limited jurisdiction of these entities, the eradication 

programs would lack regional or national coordination, which could result

in the spread of ALB to other host trees over a larger geographic area. 

The expansion of ALB beyond the current areas could result in additional 

stressors to host trees, causing both economic and environmental impacts. 

Abiotic and biotic stressors (e.g., climate change, other invasive pests, and 

air pollution) all pose threats to ALB-host trees; the addition of ALB to 

urban and natural forest ecosystems would be expected to result in 

cumulative impacts beyond those already identified as potential stressors

(Horsley et al., 2002; Poland and McCullough, 2006; Iverson et al., 2008).

Economic losses to the timber and maple syrup industries would be 

anticipated, as well as increased costs to homeowners that choose to treat

trees or have them removed once they are infested. Economic data for the 

loss of ash trees in Ohio from an invasive pest, which is just one of the 

hosts for ALB, show that landscape loss, tree removal, and replacement 

costs could range between $1.8 and $7.6 billion due to the emerald ash 

borer (Agrilus planipennis) (Sydnor et al., 2007). The loss of one tree 

species is significant; ALB has many more host trees than emerald ash 

borer.

Cumulative impacts to the environment would also be expected as ALBhost trees are lost from urban and natural forests. The potential for 

cumulative impacts would be dependent upon whether trees are removed 

from urban or forested areas, and their dominance in those areas. Tree 

removal, under the various alternatives, could result in impacts to soil and 

water quality. These impacts are reduced by implementation of BMPs. In 

urban areas, residential and business development result in soil 

disturbance and potential water quality impacts due to land disturbance, 

and increase impervious surfaces which have the ability to transport a 

variety of pollutants to surface and ground water. 

ALB eradication efforts in urban areas are expected to have incrementally 

minor impacts to environmental quality when put in the context of other 

activities that may impact air, soil, and water. In forested areas, the 

cumulative impacts from tree removal may result in cumulative impacts to 

soil and water quality, resulting in increased erosion and transport of 

sediments and nutrients to water and, in particular, in cases where large 

areas of timber are removed in proximity to water, or from watersheds 

vulnerable to soil erosion. The magnitude of these contributions to natural 

and other man-made sources of sediment and nutrients will vary, 

depending on site-specific conditions and other activities that may be 

occurring in a given watershed. The potential for cumulative impacts in 

these scenarios would be reduced due to the implementation of BMPs by 

the Program, where applicable. The selection of an alternative that will 

IV. Environmental Consequences 87
ensure eradication will reduce the likelihood of cumulative impacts 

occurring over a larger geographic area. There would be some loss of

wildlife habitat in areas where host trees are removed; however, those 

losses would not be considered permanent because in unmanaged habitats 

(e.g., woodlots), stumps of high-risk host trees would be allowed to

resprout, and replanting activities may occur in managed areas. 

Cumulative impacts to human health and the environment are anticipated 

to be incrementally minor for the proposed use of herbicides. All three 

herbicides have agricultural and non-agricultural (e.g., right-of-way and 

forestry) uses. FS uses triclopyr and, to a lesser extent, imazapyr in many 

of its invasive weed control programs where ALB-host trees are present. 

The proposed use of herbicides in the ALB Eradication Program is not 

expected to contribute significantly to the overall use of herbicides by 

other entities. The Program applies herbicides to stumps or sprouting 

vegetation from cut stumps, using hand painting or backpack spray 

applications that minimize offsite transport of the proposed formulations.

Recent ALB eradication efforts suggest that stump removal is the 

preferred treatment method, with greater than 75 percent of the stumps 

being removed rather than being treated with an herbicide. 

Imidacloprid is widely used in urban and agricultural settings; however, 

the increase in loading beyond current use, in addition to that which could 

be added due to ALB treatments, is difficult to quantify because the 

number of treated trees is unknown relative to current use patterns for 

areas where ALB-host trees may occur. In addition, the use of 

imidacloprid under the preferred alternative would vary because of the

choice of tree removal and insecticide treatment. 

Cumulative impacts from the proposed use of imidacloprid would not be 

expected to result in significant impacts to human health. The toxicity 

profile, method of application, and notification to the public regarding its 

use would minimize exposure and risk to the public. Adherence to label 

requirements would also minimize exposure and protect human health for 

workers involved with ALB eradication efforts. 

The amount of imidacloprid added to the environment would be greatest 

under alternative 4 because high-risk host trees within a 1⁄2-mile radius of

infested trees would receive treatment, compared to the preferred 

alternative where only select trees would receive imidacloprid treatments. 

The cumulative risk to aquatic resources would be greatest when 

considering large-scale imidacloprid treatments of deciduous trees, such as

ALB-host trees. Imidacloprid residues in leaf litter from treated trees can

be transported to aquatic environments and result in sublethal impacts to 

some aquatic invertebrates (Kreutzweiser et al., 2007; Kreutzweiser et al., 

88 IV. Environmental Consequences
2008b; Kreutzweiser et al., 2009). In those studies, the more significant 

impacts occurred in cases where exposure to imidacloprid in leaf litter was 

at concentrations greater than anticipated under the current proposed use 

pattern. These impacts are selective to certain types of aquatic 

invertebrates due to their feeding preference, and would not be anticipated 

for other aquatic invertebrates. Cumulative impacts from the addition of 

treated leaves would be expected to only occur for some aquatic 

invertebrates in cases where host trees are a dominant species and large 

numbers are treated. The cumulative impacts to aquatic invertebrates 

would also be reduced by the presence of non-treated leaf litter and other 

organic matter present in aquatic habitats.

Streams that may already be impacted by other factors could have

cumulative impacts related to imidacloprid use in cases of large-scale

treatments. Available water monitoring data for imidacloprid and other 

neonicotinoid insecticides in the United States shows that detections are 

common in urban and agricultural areas (Phillips and Bode, 2004; Starner 

and Goh, 2012; Hladik et al., 2014). These detections occur along with 

multiple other pesticides, and other organic and inorganic contaminants. 

Water quality data show pesticide mixtures to be a common occurrence.

Water quality data collected by the U.S. Geological Survey, as part of a 

national monitoring effort, shows that 50 percent of the surface water 

samples contain four or more pesticides in urban, agricultural, and mixeduse watersheds (Gilliom et al., 2007). The impact of these mixtures on 

human health and aquatic ecosystems is poorly understood. Chemical 

mixtures may have additive, synergistic, antagonistic, or potentiation 

effects on biological systems. Studies testing imidacloprid and other 

chemical mixtures have reported results showing no interactions between 

chemicals or additive, synergistic, and antagonistic effects to test 

organisms (Chen et al., 2010; Loureiro et al., 2010; Zhang et al., 2010;

Pavlaki et al., 2011). The chemical mixture, timing and level of dosing, 

and endpoints measured were all variables that can impact how these 

chemicals may act in combination. Interactions between pesticides, such 

as imidacloprid and other stressors (e.g., water quality and predators) have 

also been reported for various aquatic and terrestrial species (Holmstrup et 

al., 2010; Laskowski et al., 2010).

Uncertainties regarding the prediction of effects to nontarget organisms 

from imidacloprid and all possible mixtures, as well as the large area of 

the United States that is being considered in this EIS, make it difficult to 

determine cumulative impacts from program insecticide treatments. 

However, the incremental increase in risk due to imidacloprid use is 

expected to be minor for aquatic communities because the potential for 

imidacloprid risk to aquatic habitats is low; this is based on the proposed 

IV. Environmental Consequences 89
method of application, environmental fate, and available information 

regarding imidacloprid effects to aquatic organisms. 

Cumulative impacts to terrestrial wildlife associated with imidacloprid 

use are also expected to be incrementally minor for most animals. 

Imidacloprid residues on food items for mammals and birds are not 

expected to result in significant risk to wildlife. The low risk to mammals 

and birds suggests that any cumulative impacts of imidacloprid would be 

minor when put in context with other stressors, such as loss of habitat. 

Imidacloprid will affect sensitive nontarget invertebrates that consume 

plant material from treated trees; however, the mode of action of 

imidacloprid, and the method of application, which is targeted to certain 

trees, will reduce impacts to most nontarget invertebrates. The risk to 

sensitive terrestrial invertebrates from proposed imidacloprid applications 

is expected to be minor in relation to other stressors, such as other 

pesticide applications and loss of habitat. The lack of significant 

cumulative impacts to most terrestrial invertebrates will also ensure that 

mammals and birds that prey on insects are not impacted. 

Large-scale treatment of trees using imidacloprid could also increase

pesticide exposure to pollinators above current levels. A variety of factors 

stress native pollinators, as well as honey bees. Stressors include 

environmental pollution, habitat loss, poor nutrition, pests and diseases 

(e.g., Varroa mites on honey bees), and some pesticides, including 

imidacloprid (Potts et al., 2010; USDA, 2012; Sanchez-Bayo and Goka, 

2014). Recent studies have shown that honey bees exposed to sublethal

concentrations of insecticides and pathogens indicate interactive negative 

effects from exposure (Alaux et al., 2010; Pettis et al., 2012).

Interactions between imidacloprid, as well as other neonicotinoids and 

pathogens (e.g., Nosema), have resulted in colony and immune function 

impacts to honey bees (Alaux et al., 2010; Vidau et al., 2011; Pettis et al., 

2012). Colony collapse disorder (CCD) is a problem impacting domestic 

honey bee populations, with potentially significant impacts regarding 

pollination of agricultural and native plants. The causal agents for CCD 

are a complex variety of stressors, of which imidacloprid and other 

insecticides may contribute (USDA, 2012; Lu et al., 2014). The potential 

for exposure and cumulative impacts to honey bees, and other pollinators, 

from imidacloprid use is reduced by the availability of other species of

flowering plants, and selectively treating trees in the ALB quarantine area.

90 IV. Environmental Consequences
B. Special Programmatic Considerations

a. Endangered Species Act

Section 7 of the ESA and its implementing regulations require Federal 

agencies to ensure their actions are not likely to jeopardize the continued 

existence of listed threatened or endangered species, or result in the 

destruction or adverse modification of critical habitat.

(1) Potential Effects of ALB Establishment on Listed Species

ALB has the potential to affect listed species and their habitats throughout 

the United States. ALB-host species, including maple, poplar, and birch, 

among others, play a critical role in the life histories of numerous listed

species; impacts to these host species could affect their survival and 

recovery. Approximately 60 federally listed species and their critical 

habitats could be impacted by the introduction and spread of ALB in the 

United States based on the co-occurrence of preferred ALB-host trees and 

forest-dependent listed species in the Northeastern and mid-Atlantic areas

(figure 4–2). Approximately half of the species in these areas are listed 

freshwater mussels, while approximately 18 percent are listed terrestrial 

plants. The remaining listed species are primarily mammals and fish. 

Widespread establishment of ALB in the United States will cause 

significant ecological damage. Impacts to terrestrial and aquatic fauna and 

flora are expected, especially in areas where ALB-host plants are 

prevalent. T&E species that depend on ALB-host trees would be most 

affected. The extent of damage and its impact on ecological community 

function would be dictated by multiple factors. In cases where the host 

trees are not a dominant component of the forest stand, impacts may be 

less; however, in situations where host trees occur in high density and are 

keystone species within that particular forest type, the impacts are almost 

certain to be significant.

(2) Potential Effects of the ALB Program on Listed Species

Effects to listed species from the proposed alternatives for eradicating 

ALB may also pose a risk to protected species and their designated critical 

habitat without proper mitigation. A recent example of these impacts is 

with listed bat species that may occur where ALB eradication efforts are 

currently implemented. Bat species in the program area (e.g., Indiana bat 

and northern long-eared bat) use trees for roosting, as travel corridors, and 

as foraging habitat. A portion of these trees could be ALB-host trees that 

may require removal. 

1. Applicable 

Environmental

Statutes

IV. Environmental Consequences 91
Figure 4–2. Federally listed threatened and endangered species by county that co-occur with ALB-host 

trees in the Northeastern United States.

Direct effects are those effects that are the result of the direct or immediate 

effects of the project on the species or its habitat. For bats, these effects 

can include increases in disturbance (i.e., in the form of noise, human 

activity, and vibrations from equipment) from tree clearing and would

vary in intensity, depending upon the source (chainsaws, chippers, stump 

grinders, trucks). Tree removal can result in loss of maternity and nonmaternity roost trees. Removal of roost trees could impact bats by 

requiring them to expend time and energy to identify an alternate roost 

site. Removal of an unidentified roost tree during the summer occupancy 

season could result in crushing or injury of bats.

Indirect effects to bat species are those effects that are caused by or would

result from the proposed action and are later in time, but are still 

reasonably certain to occur. These effects could result from reduction of 

bat insect prey from exposure to insecticides or herbicides. Tree removal

may also indirectly affect bats by decreasing roost and habitat availability, 

92 IV. Environmental Consequences
and requiring additional time to forage and search for suitable roost trees. 

Elimination or significant reduction of fence rows and tree lines (used as 

travel corridors) may require bats to expend additional energy to find 

alternative routes. 

The removal of ALB-host trees can also impart beneficial effects to bats 

by creating canopy openings and more open understory, providing a 

higher quality habitat and an increase in maternity trees. Beneficial effects 

to bats from removal of ALB-host trees could create canopy openings in 

the interior of forests; this would increase solar exposure that may allow 

these larger trees to become suitable as maternity habitat. In addition, 

many of the trees removed are smaller trees; this would create a more 

open understory, providing higher quality habitat.

Other listed terrestrial species may also be impacted by ALB eradication 

activities. Physical disturbance of areas where ground-nesting listed 

species occur can also have direct and indirect impacts. For example, 

disturbance of nesting areas of listed birds during the breeding season 

could occur from program activities near breeding areas. Disturbance can

result in temporary abandonment of nests, exposing adults to aerial 

predation, and eggs and chicks to predation and inclement conditions. 

Tree removal activities may also result in take of listed species that may

not be able to disperse during tree removal activities, and could be crushed 

by equipment. Forest-inhabiting plant species (e.g., running buffalo 

clover and small whorled pogonia) may be affected by clearing infested 

trees that would decrease forest floor shade, thus reducing habitat 

suitability. Tree removal could also result in trampling or physical 

destruction of plant populations. Insecticides applied to host trees could 

reduce pollinators of listed plant species. Program application of 

herbicides to stumps could directly harm listed plants if they are near

treatments. 

ALB-host trees serve to protect water quality; their removal can 

destabilize stream banks resulting in excess sedimentation which would be 

detrimental to listed freshwater mussels (e.g.,fanshell and pink mucket 

pearlymussel), fish, or other aquatic species in the vicinity of an ALBinfested area. As previously mentioned, over half of the listed species in 

the Northeastern United States that could be impacted by the loss of 

ALB-host trees are aquatic. Sedimentation and changes to water quality 

from tree loss (temperature, shading, and pesticide residues) may result in 

impacts to aquatic species due to program activities. 

IV. Environmental Consequences 93
(3) Consultation History

APHIS considers whether listed species, species proposed for listing, or 

critical habitat are present in the proposed program area. If none are 

present, no Section 7 consultation is required. If species or critical habitat 

is present in the proposed program area, APHIS conducts Section 7 

consultation with the FWS and NMFS, on a site-specific basis for ALB 

eradication activities. 

For the ALB Eradication Program in Worcester County, Massachusetts, 

APHIS consulted informally with FWS on a threatened plant, the small 

whorled pogonia, Isotria medeoloides, in 2008. In 2011, APHIS consulted 

informally with FWS on the impact of the eradication program on the 

small whorled pogonia and piping plover (Charadrius melodus) in 

Norfolk and Suffolk Counties in Massachusetts. 

In June, 2011, APHIS first contacted the FWS in Columbus, Ohio for 

technical assistance regarding impacts to federally listed species in 

Clermont County, Ohio. Seven endangered species (Indiana bat, Myotis 

sodalis; running buffalo clover, Trifolium stoloniferum; fanshell, 

Cyprogenia stegaria; rayed bean, Villosa fabalis; snuffbox, Epioblasma 

triquetra; pink mucket pearlymussel, Lampsilis abrupta; and sheepnose, 

Plethobasus cyphyus) occur in Clermont County. Since that time, APHIS 

submitted biological assessments and consulted with FWS on those 

species, receiving concurrence with their “may affect, not likely to 

adversely affect” determinations, with the implementation of protection 

measures. In addition, FWS personnel made site visits to the infested area 

and have provided Indiana bat training to APHIS and the Ohio 

Department of Agriculture personnel. Also, APHIS conducted surveys for 

the Indiana bat, and other bat species, in the Clermont County eradication 

work zones and reported those findings to FWS. Most recently, APHIS 

entered into a formal consultation with FWS on the Indiana bat (receiving 

a biological opinion, dated June 4, 2014) and a conference on the northern 

long-eared bat (Myotis septentrionalis), a species proposed for listing as 

endangered. APHIS received a northern long-eared bat conference 

opinion on July 3, 2014. 

APHIS would continue to consult with FWS or NMFS, as necessary, 

when a known ALB infestation has been confirmed. In addition, APHIS 

would implement measures prior to the initiation of program activities to 

protect federally listed species and critical habitat.

94 IV. Environmental Consequences
b. Migratory Bird Treaty Act

The Migratory Bird Treaty Act of 1918 (16 U.S.C. 703–712) established a

Federal prohibition, unless permitted by regulations, to pursue, hunt, take, 

capture, kill, attempt to take, capture or kill, possess, offer for sale, sell, 

offer to purchase, purchase, deliver for shipment, ship, cause to be 

shipped, deliver for transportation, transport, cause to be transported, 

carry, or cause to be carried by any means whatever, receive for shipment, 

transportation or carriage, or export, at any time, or in any manner, any 

migratory bird or any part, nest, or egg of any such bird.

Prior ALB eradication efforts and consultations with FWS have resulted in 

several management recommendations to minimize impacts to migratory 

birds. These include:

x minimize tree removals during nesting season

x minimize disturbance as much as possible (avoid impacts to areas of

nonhost shrub/brush areas)

x replant areas that have been significantly deforested

x use existing trails for equipment to avoid disturbance to pastures/open

fields that could be used as breeding sites for ground-nesting birds

x have the names and contact information for local wildlife rehabilitators

so that if there is an issue (e.g., as a raptor nest or fledging in the area), 

guidance can be provided regarding how to handle the situation

c. Bald and Golden Eagle Protection Act

The Bald and Golden Eagle Protection Act (16 U.S.C. 668–668c) prohibits

anyone, without a permit issued by the Secretary of the Interior, from 

“taking” bald eagles, including their parts, nests, or eggs. The Act 

provides criminal penalties for persons who “take, possess, sell, purchase,

barter, offer to sell, purchase or barter, transport, export or import, at any 

time or any manner, any bald eagle...[or any golden eagle], alive or dead,

or any part, nest, or egg thereof.” The Act defines “take” as “pursue, 

shoot, shoot at, poison, wound, kill, capture, trap, collect, molest or 

disturb.”

Without the implementation of the protective measures outlined below, 

tree cutting could disturb nesting eagles. FWS has recommended buffer 

zones from active nests which require different levels of protection (FWS, 

2007). They are as follows:

IV. Environmental Consequences 95
x Avoid clear-cutting or removal of over-story trees within 330 feet of a

nest at any time. (The Program will not use clear-cutting under any 

alternative discussed in this document.)

x Avoid timber harvest operations (including road construction, and 

chain saw and yarding operations) during the breeding season, within 

660 feet of the nest. The distance may be decreased to 330 feet around

alternate nests within a particular territory—

x including nests that were attended during the current breeding 

season but not used to raise young, and

x after eggs are laid in another nest within the territory have hatched.

To ensure that program activities do not disturb eagles, APHIS would 

contact State fish and wildlife agencies, as well as the FWS, to determine 

the location of eagle nests in the program area. APHIS would also work 

with the FWS prior to any tree removal during the breeding season within 

660 feet of a nest to confirm that all eagles have left the nest. Outside of 

the breeding season, cutting may occur within the buffer zone around 

nests.

d. National Historic Preservation Act

Section 106 of the National Historic Preservation Act requires Federal 

agencies to evaluate the potential impacts of their actions on historic 

properties. Historic properties are those that are on the National Register 

of Historic Places or meet the criteria for the National Register (NHPA, 

2014). To date, the ALB Eradication Program has met its Section 106 

responsibilities by contacting the State Historic Preservation Office 

(SHPO) in each State where eradication activities may occur. Due to the 

programmatic approach used in this EIS, and the uncertainty regarding 

where an ALB infestation may occur, APHIS has not contacted SHPOs in 

States where infestations have not occurred. APHIS will continue its 

current policy of evaluating program impacts to historical properties, and 

working with the SHPO in States with known ALB infestations.

e. Executive Order 13045 

Executive Order (EO) 13045, “Protection of Children from Environmental 

Health Risks and Safety Risks,” acknowledges that children, as compared 

to adults, may suffer disproportionately from environmental health and 

safety risks due to their developmental stage, greater metabolic activity

levels, and their behavior patterns. This EO (to the extent permitted by 

law and consistent with the agency’s mission) requires each Federal

96 IV. Environmental Consequences
agency to identify, assess, and address environmental health risks and

safety risks that may disproportionately affect children. An analysis of the 

potential impacts to children from the proposed alternatives, including the 

available human health risk assessments for proposed program pesticide 

use, suggest that no disproportionate risks to children are anticipated.

f. Executive Order 12898 

EO 12898, “Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations,” focuses Federal attention on 

the environmental and human health conditions of minority and lowincome communities, and promotes community access to public

information and public participation in matters relating to human health

and the environment. This EO requires Federal agencies to conduct their

programs, policies, and activities that substantially affect human health or

the environment in a way so as not to exclude persons and populations

from participation in or benefiting from such programs. It also enforces

existing statutes to prevent minority and low-income communities from

being subjected to disproportionately high or adverse human health or 

environmental effects. 

The human health and environmental effects resulting from the preferred 

alternative are expected to be minimal, and are not expected to have 

disproportionate adverse effects to any minority or low-income family. 

Low-income families may depend on woodlots for firewood to heat their

homes; however, the most valuable species used for firewood (including 

oak, hickory, beech, and locust) are not ALB-host species and would not 

be removed. Although some maple species may be less valued for 

firewood, they are commonly used for that purpose and are a preferred 

ALB-host. Nevertheless, if no action is taken, allowing ALB to spread 

could result in permanent loss of maples and all other ALB-hosts from the 

area. For full host removal, stumps from high-risk host trees in woodlots 

may be allowed to resprout, which would then allow more rapid regrowth. 

Wood treated with imidacloprid and used as firewood is not expected to 

cause adverse health effects. Therefore, the human health and 

environmental effects from the action alternatives are not expected to have 

disproportionate adverse effects to any minority or low-income family.

g. Executive Order 13175

EO 13175, “Consultation and Coordination with Indian Tribal 

Governments,” was issued to ensure that there would be “meaningful 

consultation and collaboration with tribal officials in the development of 

Federal policies that have tribal implications....” APHIS prepared and 

sent a letter to each of the tribes in the contiguous United States in June, 

2013, prior to publishing the NOI to prepare the EIS. The letter provided 

IV. Environmental Consequences 97
background on ALB in the United States, and provided the tribes an 

opportunity to dialogue with APHIS regarding potential impacts to tribal 

resources. APHIS also hosted a teleconference with all interested tribes in 

July, 2013, to discuss the Program and answer any questions from tribal 

representatives. APHIS will continue to actively engage with the tribes on 

eradication program activities, and address questions and concerns. This 

would occur through tribal consultation prior to the development of sitespecific EAs.

h. Executive Order 13186 

EO 13186, “Responsibilities of Federal Agencies to Protect Migratory 

Birds,” directs Federal agencies taking actions with a measurable negative 

effect on migratory bird populations to develop and implement a 

memorandum of understanding (MOU) with FWS that promotes the 

conservation of migratory bird populations. On August 2, 2012, an MOU

between APHIS and FWS was signed to facilitate the implementation of 

this EO. The MOU provides APHIS with guidance to avoid and 

minimize, to the extent practicable, detrimental migratory bird habitat 

alteration or unintentional take during management activities.

i. Other Federal and State Regulations and Statutes

Other Federal and State regulations may also apply to the proposed 

alternatives identified in this EIS. APHIS complies with all applicable 

Federal regulations and Executive orders discussed in this EIS, such as 

the:

x Clean Air Act,

x Clean Water Act,

x Coastal Zone Management Act, and

x Federal Insecticide, Fungicide and Rodenticide Act.

States may also have applicable regulations regarding various proposed 

activities related to the ALB Eradication Program. APHIS works 

cooperatively with State agencies in the implementation of any proposed 

ALB activities, and to identify applicable State regulations to ensure 

compliance.

APHIS recognizes that the various alternatives proposed in this EIS may 

pose some risk to human health and the environment. This includes the no 

action alternative, as well as the proposed alternatives that were evaluated 

in this EIS. Many of the potential risks associated with implementation of 

an eradication program can be mitigated based on program requirements 

and, in the case of pesticide use, Federal regulations; this includes 

2. Mitigation 

and Risk 

Reduction

98 IV. Environmental Consequences
pesticide label language to reduce risk to human health and the 

environment. In addition, coordination with State agencies and other 

stakeholders on site-specific eradication efforts ensures that other State 

and local requirements are considered and implemented, as appropriate. 

Hazards to the public from tree removal in urban and natural areas are 

mitigated through proper notification to ensure that the public would not 

be in areas when tree removal operations are taking place. All tree 

removals are coordinated with the respective landowners prior to any 

removal. Notification to landowners also occurs when chemical 

treatments may be used to kill stumps (herbicides) or treat high-risk host 

trees for ALB (insecticide). In addition to the notification process, there 

are other risk reduction requirements for pesticide use that are designed to 

protect workers, as well as the general public, and the environment. The 

mitigations are included on the pesticide label for a given formulation, and 

must be followed to ensure compliance with applicable Federal statutes. 

The greatest potential for human exposure to program pesticides is for 

workers who handle the concentrated form of each product and make 

applications. In the case of workers, there are several requirements for 

PPE that will reduce exposure and risk including the use of:

x long sleeved shirt and long pants,

x protective eyewear,

x chemical resistant gloves, and

x shoes and socks.

These PPE requirements are based on the known toxicity profile for each 

of the proposed pesticides and the various formulations. Other labeling 

restrictions (e.g., applicable reentry intervals) are also designed to protect 

the public, including children as well as domestic pets. 

Risk reduction to the environment from the proposed alternatives may 

occur through program requirements, as well as pesticide labeling to 

restrict use. As an example of program measures to reduce risk, the 

current eradication activities in Ohio are implementing Ohio Department 

of Forestry BMPs that have been developed to protect soil and water 

quality during tree removal operations (Ohio Department of Natural 

Resources, nd). These BMP’s identify stream management zones (SMZs) 

that are protected areas that have been established adjacent to bodies of 

water that increase with increasing slope (Ohio Department of Natural 

Resources, nd). These types of buffers have been shown to provide 

protection to receiving waters from sedimentation and nutrients that may 

be of concern for a given watershed (Wenger, 1999).

IV. Environmental Consequences 99
Excess sediments and nutrients are primary causes for listing waterways in 

the United States as impaired, under Section 303(d) of the CWA. The 

SMZs are areas where no, or very limited, cutting would be allowed. 

Infested ALB-host trees that could occur within a SMZ would still need to 

be selectively removed, but without the use of heavy equipment. This 

could also occur with some high-risk host trees; however, in those cases, 

the removals would only be conducted with landowner approval and 

consultation with other Federal and State agencies to ensure the risk to 

water quality is minimized.

The risk to human health and the environment from the offsite transport of 

pesticides that are proposed for use in the ALB Eradication Program may 

also be reduced by pesticide labeling requirements designed to reduce the 

potential for contamination. Labeling restrictions and recommendations 

regarding application rate, timing of application, and application proximity 

to sensitive areas are all designed to reduce the risk of effects to human 

health and the environment. In addition, pesticide storage and disposal 

requirements are designed to reduce the risk of accidental spills and 

contamination of areas which could result in effects to human health and 

the environment. 

APHIS conducts various monitoring for several of its programs. 

Monitoring efforts are typically directed towards measuring potential 

exposure to program pesticide treatments. Monitoring may consist of grab 

samples collected from different matrices (e.g., soil, water, air, biota) 

based on potential concerns regarding exposure which may occur to the 

environment and human health. These monitoring efforts are conducted to 

support analysis and compliance with applicable Federal regulations, such 

as the NEPA, ESA, and Federal Insecticide Fungicide and Rodenticide 

Act. Monitoring efforts in previous and current ALB eradication 

programs have been directed towards analysis of imidacloprid in various 

matrices (APHIS, 2013a). The objectives of the ALB environmental 

monitoring program are to:

x demonstrate the effectiveness of ALB-operational procedures in 

excluding or minimizing exposure of the public and the environment 

to Program-applied imidacloprid;

x collect data which can be used to evaluate whether the assumptions 

used in the environmental assessments are valid estimates of potential 

exposure of the public and the environment to Program-applied 

imidacloprid; and

x investigate any Program-related complaints or reports of adverse 

effects on public health, worker safety, environmental quality, or 

nontarget species.

3. Program 

Monitoring

100 IV. Environmental Consequences
4. Irreversible 

and 

Irretrievable 

Commitment 

of 

Resources

The APHIS environmental monitoring staff coordinates the collection, 

packaging, and shipment of samples to accredited laboratories for 

processing and analysis according to standard operating procedures 

(APHIS, 2013a). The results of the laboratory’s residue analyses are then 

correlated with environmental conditions data recorded at the time of 

treatment and sampling. The APHIS’ environmental monitoring staff

further analyzes the results to determine whether there are any human or 

environmental risks related to the use of the pesticide. The monitoring 

staff reports the data and analyses to Program managers at the end of the 

program, or intermittently during the program, as required.

ALB-related environmental monitoring for imidacloprid has occurred in 

Massachusetts and New York. To date, monitoring efforts for 

imidacloprid have focused on soil, water, plant, and bee-related samples to 

evaluate potential residues. Monitoring efforts will continue to be 

evaluated on a site-specific basis for any current and potential new 

infestations in the future. 

APHIS has been working on ALB eradication efforts since the beetle was 

first discovered in Brooklyn, New York, in 1996. Subsequently, resources 

have been committed to address infestations, as well as conduct research 

to understand the impacts of ALB introduction into the United States. 

Research to develop successful eradication methods have occurred, and 

will continue, so that APHIS implements the most effective methodologies 

in current and future infestations. Since the initial infestation, other 

infestations have been documented requiring additional APHIS resources. 

APHIS works with multiple stakeholders regarding the implementation of 

ALB-eradication activities. This includes cost-sharing to implement 

various aspects of the ALB Eradication Program. Federal share of the 

total costs to operate ALB eradication activities has varied from 45 to 

95 percent since the first Program was initiated (table 4–1). To date, 

Federal spending for the ALB Eradication Program has been over $500 

million. 

IV. Environmental Consequences 101
Table 4–1. ALB Eradication Program Historical Cost-Share Contributions 

(from 1997 to 2009 (thousands of dollars)).

Fiscal 

Year

Federal 

Funding

(Appropriated 

+ Emergency 

Funding)

Cooperator 

Funding Total Federal 

Share

1997 849 149 998 85%

1998 1,327 1,634 2,961 45%

1999 5,510 2,573 8,083 68%

2000 16,180 1,555 17,735 91%

2001 49,098 2,654 51,752 95%

2002 31,656 4,000 35,656 89%

2003 33,181 4,000 37,181 89%

2004 42,851 4,000 46,851 91%

2005 28,933 11,071 40,004 72%

2006 19,859 11,218 31,077 64%

2007 19,904 13,731 33,635 59%

2008 19,867 11,602 31,469 63%

2009 44,618 16,052 60,670 74%

2010 74,472 12,856 87,328 85%

2011 32,456 9,843 42,299 77%

2012 56,732 4,191 60,923 93%

2013 39,731 2,240 42,151 94%

Total $517,057 $111,599 $628,656 79%

102 IV. Environmental Consequences
Appendix A. Preparers

U.S. Department of Agriculture

Animal and Plant Health Inspection Service

4700 River Road

Riverdale, MD 20737 

_____________________________________________________

James E. Warren

Environmental Toxicologist

B.S. Forest Management

M.S. Entomology

Ph.D. Environmental Toxicology

Background: Environmental Protection Specialist in Environmental and 

Risk Analysis Services, with over 18 years of experience in environmental 

toxicology and risk assessment, as well as environmental fate modeling of 

pesticides while working for the Federal government and the agrochemical 

industry.

EIS Responsibility: Project Lead for the Draft Programmatic ALB

Eradication Program EIS. Reviewed various chapters and contributed in 

writing various sections in the EIS, with an emphasis on the 

Environmental Consequences chapter. Coauthor for the chemical human 

health and ecological pesticide risk assessments. 

Andrea Lemay

Biological Scientist

B.S. Plant and Soil Science

M.S. Plant Pathology

Background: Biological scientist and plant pathologist in Environmental 

and Risk Analysis Services, with over 11 years of experience in risk 

analysis while working for the Federal government.

EIS Responsibility: Analyst for the Draft Programmatic ALB Eradication 

Program EIS. Reviewed various chapters and contributed in writing the 

Alternatives, Affected Environment, and Environmental Consequences

chapters.

Robyn Rose

National Policy Manager

B.S. Agronomy

M.S. Entomology

Ph.D. Entomology

Principal Draft 

EIS Contributors

Appendix A. Preparers A–1
Background: Domestic National Policy Manger in Plant Protection and 

Quarantine’s (PPQ) Plant Health Programs, with 17 years of experience as 

an environmental risk assessor and program manager.

EIS Responsibility: Providing technical expertise regarding Draft 

Programmatic ALB Eradication Program EIS and the program, and 

serving as the primary reviewer for PPQ.

Vivian A. Miller

Environmental Protection Specialist

B.S. Biology

M.Ed. Secondary Education, Biology

Background: Environmental protection specialist with over 4 years of 

experience preparing and reviewing NEPA compliance documents for 

APHIS. 

EIS Responsibility: Analyst for the Draft Programmatic ALB Eradication 

Program EIS. Reviewed various chapters and contributed in writing the 

Affected Environment and Environmental Consequences chapters.

Tracy A. Willard

Environmental Protection Specialist

B.S. Biology

M.S. Entomology

Ph.D. Entomology

Background: Fourteen years of service with APHIS preparing 

environmental documents. Experience in environmental compliance,

especially as associated with the Endangered Species Act. 

EIS Responsibility: Analyst for the Draft Programmatic ALB Eradication 

Program EIS. Prepared chapter 1 and reviewed various chapters. 

Fan Wang-Cahill

Environmental Health Specialist

B.S. Biology 

M.S. Hydrobiology

Ph.D. Botany

Background: Eighteen years professional experience in human health risk 

assessment for environmental contaminants at Superfund, Resource 

Conservation and Recovery Act, and State-regulated contaminated 

facilities. Expertise in preparing human health risk assessments for 

APHIS.

A–2 Appendix A. Preparers
EIS Responsibility: Analyst for the Draft Programmatic ALB Eradication 

Program EIS. Contributed in writing the human health effects of the 

environmental consequences chapter.

Allan N. Auclair

Systems Ecologist

B.S. General Science

Ph.D. Plant and Systems Ecology

Background: Risk scientist with expertise on pest risk assessment, pest 

outbreak dynamics, and the role of climate drives and climate change on 

pest incidence. Eight years of service in APHIS. Experience in risk 

analysis especially as it relates to risk assessment of exotic pests entering 

on commodities under import permit application; climate as a drive on the 

outbreak of high-threat pests; and compliance to climate change and 

invasive pest legislation including Executive Orders 13122 and 13514 and

Departmental Regulation 1070–001.

EIS Responsibility: EIS analyst – evaluated the effects of removing ALBinfested trees on greenhouse gas (GHG) emissions, and the effects of 

climate change impacts on/by tree removal actions. Identified 

management alternatives and “preferred option” to minimize impacts. 

Eleni C. Tsigas

Agricultural Economist

B.S. Mathematical Economics

Ph.D. Agricultural Trade and Policy

Background: Applied economist analyzing the economic impact(s) from a 

proposed change in an agricultural policy/rule (domestic or foreign) and 

presenting the decision makers with the outcome of the potential economic 

benefits and costs for all the participants. Sixteen years of service with 

APHIS’ Policy Analysis and Development Programs Division.

Worked as an analyst with the International Markets Division in Economic 

Research Service of USDA, and in the International Food and Policy 

Research Institute (IFPRI) for 7years.

EIS Responsibility: Economic analyst 

Appendix A. Preparers A–3
(This page is intentionally left blank.)

A–4 Appendix A. Preparers
Appendix B. List of ALB NEPA Links Inventory of 

USDA Analyses to Date with Links to the 

Resources

Asian Longhorned Beetle Cooperative Eradication Program in Clermont County, Ohio, Revised 

Environmental Assessment, May 2013 (PDF; 2.65 Mb)

x FONSI signed May 1, 2013 (PDF: 71 Kb) 

Asian Longhorned Beetle Cooperative Eradication Program in Clermont County, Ohio, 

Environmental Assessment, May 2012 (PDF; 1.27 Mb)

Asian Longhorned Beetle Eradication Efforts in Clermont and Brown Counties, Ohio, 

Environmental Assessment, September 2011 (PDF; 3.03 Mb)

x FONSI signed September 6, 2011 (PDF; 103 Kb) 

Asian Longhorned Beetle Cooperative Eradication Program in Essex, Norfolk and Suffolk 

Counties, Massachusetts, Environmental Assessment, May 2011 (PDF; 83 Kb)

x FONSI signed May 20, 2011 (PDF; 4.28 Mb) 

Chemical Treatment Study in New York City, New York, and Central New Jersey for the Asian 

Longhorned Beetle Eradication Program Environmental Assessment, September 2010 (PDF; 

5.10 Mb)

x FONSI signed September 14, 2010 (PDF; 93 Kb) 

Nursery Treatment Efficacy Study within Worcester County, Massachusetts, to Support the 

Asian Longhorned Beetle Cooperative Eradication Program, Environmental Assessment, April 

2010 (PDF; 192 Kb) 

x FONSI signed May 6, 2010 (PDF; 1.07 Mb) 

New Chemical Treatment Study within the Worcester, Massachusetts, Quarantine Zone for the 

Asian Longhorned Beetle Eradication Program, Environmental Assessment, September 2009

(PDF; 903 Kb)

x FONSI signed October 30, 2009 (PDF; 162 Kb) 

Asian Longhorned Beetle Cooperative Eradication Program in Worcester and Middlesex 

Counties, Massachusetts Environmental Assessment September 2008 (PDF; 1.28 Mb) [FONSI 

signed 11/21/08]

Appendix B. List of ALB NEPA Links B–1
x Amended FONSI signed September 11, 2009 (PDF; 140 Kb) 

x Addendum to the FONSI signed March 29, 2010 (PDF; 469 Kb) 

Asian Longhorned Beetle Cooperative Eradication Program in the New York Metropolitan Area, 

Environmental Assessment May 2007 (PDF; 43 Kb)

Asian Longhorned Beetle Cooperative Eradication Program - Hudson County, New Jersey, 

Environmental Assessment, March 2003 (PDF; 36 Kb) 

Asian Longhorned Beetle Program, Environmental Assessment, February 2000 (PDF; 892 Kb)

Asian Longhorned Beetle Field Trial, Environmental Assessment, January 2000 (PDF; 698 Kb) 

Asian Longhorned Beetle Control Program - Illinois, Environmental Assessment, August 1998

(PDF; 23 Kb)

Asian Longhorned Beetle Control Program, Environmental Assessment, December 1996 (PDF; 

23 Kb) 

B–2 Appendix B. List of ALB NEPA Links
Appendix C. ALB: Annotated Host List

Asian Longhorned Beetle: Annotated Host List

Updated By Baode Wang on February 1, 2012

Additional comments by Baode Wang on June 25, 2014

USDA-APHIS-PPQ, Center for Plant Health Science and Technology, Otis Laboratory

Genus1 Common Name Host Abundance and Other Notes2 Treated, 

Surveyed3

Preferred Host in US4

Acer Maple, boxelder Very common trees. Many US records, all species: Norway, red, 

silver, sugar, sycamore maple and boxelder especially favored; Amur 

maple less favored; Japanese maple seldom attacked.

Yes

Aesculus Horsechestnut, 

buckeye

Fairly common trees. Several US records, some heavily infested. Yes

Betula Birch Fairly common trees. Several US records: gray, European white and 

river birches. Some gray birches with many exits. Birches are 

apparently less preferred than maple. No exit holes found in 

laboratory studies with black & yellow birches yet although some larva 

developments inside trees of these two species have been observed.

Yes

Salix Willow Fairly common trees. Several US records: weeping, pussy and white 

willows highly favored; black willow (oviposition only) less favored. Yes

Ulmus Elm Very common trees. Many US records: American, Siberian and 

Chinese elms. Elms are apparently less preferred than maple. Yes

Occasional to Rare Host in US4

Albizia Mimosa, silk tree,

A. julibrissin

Occasional ornamental. Exit holes: 2 records from field in NY with 

additional emergence in laboratory. No Chinese record. Yes

Cercidiphyllum Katsura tree,

C. japonicum

Occasional ornamental. Four records from Worcester, MA, including 

2 trees with exit holes. Yes

Fraxinus Ash (especially 

green

ash, F. 

pennsylvanica)

Very common tree, but injury infrequent relative to host abundance. 

Several US records, all from IL, most of these unverified (but at least 

two exit holes confirmed). Chinese ash, F. chinensis and white ash, F. 

americana were confirmed to be host in China

Yes

Platanus London plane tree,

P. acerifolia

Very common urban trees. 12 US records (including 4 with exit 

holes, NY); no record for P. occidentalis, American sycamore. Host in 

Chinese literature. Exit holes observed in China.

Yes

Populus Poplar Very common trees. Diverse and variable group, hybrids occur. 

Suitability apparently varies; some species and hybrids are prime hosts 

in China. Nine US records (NY, NJ, MA). Complete life cycle on 

eastern cottonwood, P. deltoides and quaking aspen, P. tremuloides.

Oviposition on balsam popular, P. balsamifera, Balm-of-Gilead (a 

hybrid cultivar), unidentified Populus sp. Generally, Populus section 

Aigeiros (black poplars) are more preferred than other sections.

Yes

Sorbus European 

mountain-ash, S. 

aucuparia

Occasional ornamental. Exit hole: 1 record from field in IL with 

additional emergence in laboratory. No Chinese record. Note: this is 

not a true ash; Sorbus is a member of the rose family.

Yes

Appendix C. ALB: Annotated Host List C–1
Genus1 Common Name Host Abundance and Other Notes2 Treated, 

surveyed3

Questionable US Records4

Celtis5 Hackberry,

C. occidentalis

Fairly common tree. Oviposition: 1 unverified record from IL, with 

small/medium-sized larva identified as ALB. No Chinese record.

No egg sites were found in lab studies with caged trees and beetles 

and active egg sites or exit holes were found in surveys in China.

survey 

only

Hibiscus Rose-of-Sharon,

H. syriacus

Common ornamental shrub. Exit: 1 unverified report, NY; 

Oviposition: several records, NY, but no larval development, 

possibly incidental to heavy damage on nearby hosts. No Chinese 

record.

No

Malus Apple, crab apple Common ornamental. Oviposition: 1 questionable record, IL. Host 

in Chinese literature. Oviposition observed in China. No

Morus Mulberry Very common tree. Oviposition: 1 record, NY. No Chinese record. No

Prunus Cherry, plum Very common ornamental. Oviposition: 2 records, NY & IL, but no 

survival. Host in Chinese literature. No

Pyrus Pear Common ornamental. Exit: 1 questionable record, IL. Host in 

Chinese literature. Few exit holes were observed on Pyrus 

bretschneideri trees in China.

No

Quercus Oak,

(pin oak, Q. palustris)

Very common tree. Oviposition: 1 record, NY (incidental to heavy 

damage on nearby hosts). No Chinese record. No

Robinia Black locust,

R. pseudoacacia

Common tree. Exit: 2 doubtful records, IL. Host in Chinese 

literature. Quite a few egg sites were observed in China, no exit 

holes.

No

Tilia Linden (little-leaf 

linden, T. cordata)

Common tree. Oviposition: 2 records (IL & NY) but no survival. 

Oviposition but no survival in Canada. Host in Chinese literature. No

No US Record4

Alnus Alder Locally common tree or shrub. No US record. Host in Chinese 

literature. Exit hole observed in gray alder, A. incana, in cage study 

in China.

No

Elaeagnus Russian olive 

(Oleaster), E.

angustifolia

Widely-distributed ornamental shrub and escaped weed; quite 

variable, easily confused with other Elaeagnus species. No US 

record. Host in Chinese literature; Heavy feeding damage and few 

exit holes observed in China.

No

Koelreuteria Goldenraintree, K. 

paniculata

Occasional ornamental. No US record. Heavy feeding, oviposition 

sites and 2 exit holes observed in field studies in China. Other exit 

holes were also found on trees along roadside.

Yes

Melia Chinaberry,

M. azedarach

Uncommon shrub. No US record; reported not to be a host in 

Chinese literature but damage observed. No

Non-Host4

Ailanthus Tree of heaven,

A. altissima

Common tree. No US record; reported not to be a host in Chinese 

literature. No

C–2 Appendix C. ALB: Annotated Host Lists
Appendix D. Assessment of Greenhouse Gas Fluxes 

and Climate Change Impacts Related to 

ALB

Appendix D. Climate Change Impacts Related to ALB

Table of Contents

EXECUTIVE SUMMARY

1.0 INTRODUCTION

2.0 GHG EMISSIONS AND PROJECT IMPACT ON CLIMATE CHANGE

3.0 ALTERNATIVES

4.0 MITIGATION MEASURES

5.0 REFERENCES

ATTACHMENTS

Appendix D. Climate Change Impacts Related to ALB
Executive Summary

The five key findings in this assessment of ALB (Asian Longhorned Beetle) eradication impacts 

are:

1. Total carbon dioxide (CO2) emission from trees and soil at the Clermont County Ohio ALB 

Eradication Project site is estimated to be 7,872 metric tons (mt); total at all five ALB 

eradication sites is estimated to be 20,187 mt. These levels are below the CEQ (Council on 

Environmental Quality) reference level of 25,000 mt for all greenhouse gases (GHG); other 

GHGs (methane, nitrous oxide, hydro-fluorocarbons, perfluorocarbons, and sulfur 

hexafluoride) were not assessed in this study. Alternative scenarios of ‘no action’ indicate 

2,254 million mt of CO2 would be released from host trees in urban areas and adjacent 

forests under the current tree removal protocols across 48 States of the contiguous US. In the 

extreme scenario where all host tree species are infested by ALB across the 48 States, 13,906 

million mt would be released in the absence of any eradication.

2. Cumulative CO2 emission is zero by 76 years post-eradication where trees removed are 

artificially re-planted and/or natural forest regeneration is allowed. Most cities in the US this 

decade show diminished tree cover due to increased infrastructure (i.e., road, residential, and 

commercial building). Compared to American Forests standards of 40% urban tree cover, the 

US-wide average is 23%, indicating considerable leeway to increase CO2 sequestration and C 

storage through expansion of urban tree cover. Alternative scenarios indicate that under 

methods that enhance tree growth by 10%, provide added protection, and expand tree cover 

from 25% to 40%, complete CO2 recovery could be achieved in 43 years and total C storage 

could double over ‘business-as-usual’ approaches. 

3. Tree removal in urban areas and adjacent forest impacts negatively on building energy 

consumption, local air pollution levels, and flooding control. Promoting tree cover to nonhost, rapidly growing tree species increases adaptation to climate change. Examples are given 

of US cites with ‘greening’ programs aimed at increased tree cover to achieve benefits of 

adaptation.

4. Both host trees and ALB are strongly impacted by present and continuing climate change. In 

a study of Northeast US forests, 36 out of 80 species assessed show potential for their

ecological optima to shift at least 100 km to the north, including seven that could move >250 

km. Sugar maple (Acer saccharum, -14.5%) and black cherry (Prunus serotina, -10.0%) 

would decline sharply, while oak and southern pines would expand northward – hence an 

expected shift away from prime ALB host trees in the near future. ALB under present climate 

has the potential to occupy all 48 contiguous States. Temperature increases would enhance 

ALB survival and growth over large areas. Data on a diverse array of 612 crop pests and 

pathogens worldwide demonstrate an average pole-ward shift of 2.7 +/-0.8 km / year since 

1960, supporting the hypothesis that global warming-driven pest movement is already 

underway.

5. Long-term shifts in average temperature and total precipitation at Cincinnati, Ohio (1895-

2013) are modest, highly variable, and cyclical; temperature increased 0.42C/100 years 

compared to a global temperature change 0.73C/100 years. A simple ALB ‘Index of Climate 

Favorability’, 1950 to 2013 at Cincinnati is dominated by a cyclic pattern. Linear regression 

shows a decrease rate of 1.6 %/100 years. The present outbreak in Clermont County Ohio is 

preceded by a six year interval of favorable climate for ALB; since first detection in1996, 

Appendix D. Climate Change Impacts Related to ALB
Years 1996, 2000, 2001, 2003, 2004, 2009 stand out as particularly favorable for ALB 

growth; this contrasts to any earlier 18-year period which had only two to three such events. 

Index values suggest an overall static trend but one punctuated by especially favorable or 

adverse yearly conditions. Outbreak sites imply that ALB thrives within a ‘humidity 

corridor’ and that commonly applied degree-day models require revision to fully incorporate 

moisture parameters. 

1.0 Introduction

USDA APHIS evaluated the potential for greenhouse gas (GHG) emissions related to taking no 

action against the Asian Longhorned Beetle (ALB) and the preferred alternative which includes 

removal of infested host trees and a combination of removal and imidacloprid treatments of high 

risk host trees.

Estimating these types of emissions can be difficult to do on a national scale especially in this 

case where ALB has not been detected in areas where it could become established but could be 

in the future due to the presence of host trees and favorable environmental conditions. Estimates 

regarding the release of GHG in this assessment were quantified based on the most recent ALB 

outbreak in Ohio with information also provided on the other ALB outbreaks that have occurred 

in the United States. The emission of GHGs associated with tree removal, and GHG 

sequestration where tree replanting and regeneration are allowed (albeit into different tree 

species) was evaluated against the tree and soil carbon balances typical of similar but non ALBinfested areas.

2.0 GHG Emissions and Project Impact on Climate Change

2.1 GHG Emissions and Sequestration

2.1.1 Direct and indirect GHG emissions

Direct Emissions. The most conspicuous impact of the removal of large numbers of ALBinfested trees is the loss of CO2 sequestration and release of carbon storage in trees and soil.

As of mid-2013, about 9,400 trees had been removed in the Ohio ALB eradication program

(Table 1). 

Levels of tree removal at five ALB eradication sites were used as input to a CO2 Emissions 

and Sequestration Model. This model developed by us applied the number of trees removed 

in tree species biomass equations of the USDA Forest Service, assumptions of tree size 

distribution among urban and forest tree populations, tree carbon and soil carbon content to 

estimate total CO2 emitted to the atmosphere through decomposition of wood, and that 

sequestered from the atmosphere in regrowth over tree life expectancy of 100 years 

(Attachment 1).

Release of CO2 to the atmosphere through decomposition follows removal, cutting, and 

chipping. Rapid release initially occurs from fine, nutrient-rich branches; this is followed by 

breakdown of residual heartwood and larger branches, resulting in a transient spike of release 

Appendix D. Climate Change Impacts Related to ALB
8-12 years later. Decomposition in most temperate hardwoods is more or less complete by 

Year 22 (Fig. 1). 

Assuming artificial replanting and natural regeneration follows immediately after tree 

removal, sequestration of CO2 in new growth will match that released annually in 

decomposition by Year 16 and will completely re-capture all the CO2 released by Year 76. 

Hence, the net positive flux (to atmosphere) in early decades reverts to a net negative flux 

(from atmosphere) in later decades. This changing dynamic is an important element in the 

overall, complete assessment of CO2 impacts on GHGs (Fig. 1). Assertive management of 

tree health and expanded tree cover (as discussed below under Alternative 2) can actually 

benefit in shortening the time to full carbon recovery, and may substantially exceed the initial 

losses through better tree growth and through the selection of replacement species both 

resistant to ALB and better suited to warming conditions and associated weather variability.

The Ohio site to date is estimated to have released a total of 1762 mt of CO2, about a quarter 

of that from soil disturbance; eventually that level could rise to 7872 mt. The total eventual 

release of CO2 from all five ALB eradication sites in the northeast and north central States is 

estimated to be 20,200 mt through the near future, based on removal estimates of about 

114,000 trees (Table 1).

Figure 1. Estimates for Ohio ALB eradication program of the emission of CO2 from trees 

removed (blue) and sequestration of CO2 in new tree growth (green). Net CO2 flux (red) is 

emissions minus sequestration; dashed red line is zero net flux. Full recovery of all initial 

CO2 emission is captured in new tree growth (dashed blue line, Year 76). 

Appendix D. Climate Change Impacts Related to ALB
Table 1. Summary of tree removal levels to date (7/2013) and estimated final number at 

five locations in Northeastern United States, part of USDA APHIS Asian Longhorn Beetle 

Eradication Program. Estimated percent urban/forest, CO2 released following tree removal 

and chipping, years required for total CO2 release to atmosphere, and years required for 

total CO2 recovery through sequestration in new tree growth.

Indirect Emissions. Other GHGs tied to the carbon cycle, notably NO2 and CH4 can have 

important atmospheric warming effects but were not quantified in this study. Methane 

production following tree removal would occur where anaerobic conditions exist, such as in 

very wet or submerged soils. Nitrogen compounds that eventually may end up in the 

atmosphere as GHG are released as tree wood decomposes. The production of nitrates (-

NO3), studied in-depth by researchers more than other forms of organic nitrogen, is closely 

tied to soil processes and stream water discharge. Christopher et al (2004) observed that –

NO3 discharge from forested watersheds in New York was largely from surface soils 

following snowmelt and major storm events (i.e., the ‘flushing effect’). Even though the 

geology and hydrology of the two adjacent deciduous watersheds they studied were similar, 

the levels of –

NO3 in discharge showed significant differences -- for reasons likely attributed 

to dissimilar nitrogen-fixing and decomposition properties. The lack of ALB Program data 

on soils and soil disturbances during cutting operations makes meaningful estimates of 

methane and nitrate production/release to the atmosphere difficult. In the eastern US, 

atmospheric nitrogen deposition is high, complicating an overall assessment of nitrogen 

release due to tree removal. 

The USDA OCE (2013) recently released a draft report on Science-Based Methods for 

Entity-Scale Quantification of Greenhouse Gas Sources and Sinks from Agriculture and 

Forestry Practices. Nitrogen and methane estimates form part of the agricultural methods 

documented, but do not appear in any of the forest or tree-based management models (e.g., 

forestry, afforestation, agro-forestry, wood-carb biomass). 

Appendix D. Climate Change Impacts Related to ALB
2.1.2 GHG emissions in carbon equivalents 

The only GHG quantified in detail is CO2. Figure 1 and Table 1 are representative estimates 

of CO2 release and sequestration for the Ohio and four other ALB eradication projects to 

date. Throughout, we used the commonly reported conversion factor of 3.67 grams CO2 per 

gram of carbon. 

2.1.3 Cumulative impacts project would contribute to/have on global climate 

change 

The estimated total CO2 release from five ALB eradication sites in the northeast US is 20 

thousand mt (Table 1). This is approximately 0.024 % of total global CO2 annual emissions 

based on the Year 2010 estimate of 9.1 Gt C / year (33.5 Gt CO2) global emissions from 

industrial sources and an estimated total of 10.0 Gt C / year, including land-use change and 

deforestation ( http:// co2now.org/Current-CO2/CO2-Now/global-carbon-emissions.html accessed 

10/30/2013).

Unlike industrial emissions from fossil fuel sources, forests have the advantage of carbon 

recovery. Through sequestration in new growth, natural and artificial regeneration would recapture the equivalent of the CO2 released within 76 years. Under improved management of 

urban tree health and tree cover, the level of CO2 sequestration in new tree growth could 

exceed initial losses due to tree removal and recapture fully all CO2 within as little as 43 

years (see Alternative 2 below). 

2.2 Impacts of Project on/by Climate Change

2.2.1 Direct and indirect impact of climate change on the ALB eradication 

project

Long-term change in climate will vividly impact on both the (a) host trees (in urban settings 

as well as in natural forests) and on (b) ALB survival and population vigor (and that of most 

other invasive forest pests).

(a) Direct impact of climate change on host trees and on vegetation.

Anticipated changes in the New York City, Chicago, and Toronto urban areas (Nowak et 

al 2007, Nowak et al 2010, Toronto 2007) include:

• Warmer winter temperatures and longer growing seasons;

• Changes in the seasonality of precipitation and extreme events like droughts and 

heavy rainfalls;

• Expanded ranges of insects and increased over-winter survival rates;

• Increased frequency and severity of storm events.

Model projections for the northeastern US show a range of impacts on forest productivity 

due to anticipated climate change. The overall effect on net ecosystem productivity is 

positive (+75 gC/m2

/year but with notably large variations: from -150 to 350 gC/m2/year 

for the region, and -85 to +275 gC/m2

/year at the level of four specific sites) (Aber et al 

Appendix D. Climate Change Impacts Related to ALB
1995). Tree growth predictions vary because of the intermixing of positive and negative 

climate effects. Increases in carbon dioxide and temperature may have a positive effect 

by increasing the rate of tree growth, but only up to a point. Increased temperatures will 

also increase evapotranspiration, soil drying, and the frequency of short-term droughts, 

which would limit water availability for tree growth (Wilmont 2011). Overall, drops in 

tree productivity and associated changes in micro-climate imply stress and vulnerability 

of trees to pathogen and insect attack.

The expected shift is also toward more damaging events: increases and/or altered 

frequencies are expected for fire, drought, insect and pathogen outbreaks, prevalence of 

introduced species, hurricanes, windstorms and ice-storms (Dale and Beyeler 2001). 

Important to the issue in ALB management are large differences among major forest 

species in how and to the extent they will be affected. For example, for northeast US 

forests, Iverson and Prasad (1998) show that roughly 30 species could expand their range 

and/or weighted importance at least 10%, while an additional 30 species could decrease 

by at least 10%. Depending on the global change scenario used, 4–9 species would 

potentially move out of the United States to the north. Nearly half of the species assessed 

(36 out of 80) showed the potential for the ecological optima to shift at least 100 km to 

the north, including seven that could move >250 km. They chose Vinton County in 

southern Ohio to model climate projections -- among 15 species projected to decline, 

sugar maple (Acer saccharum, -14.5%) and black cherry (Prunus serotina, -10.0%) 

would decline sharply, while sourwood (Oxydendrum arboretum, +7.5%) and white oak 

(Quercus alba, +4.0%) would increase in importance. An additional 14 species are 

projected to change very little under the changed climate. Hence, a major ALB host is 

projected to be one of the tree species in the northeast US most affected under expected 

near-future climate shifts.

Overpeck et al (1991) predict the above general patterns for northern pines, as well as 

large increases in oak abundance in the northern Great Lakes and New England -- namely 

for black, northern red, and white oak (Quercus velutina, Q. rubra, and Q. 

alba,respectively). They also predicted a severe northern shift for white birch (Betula

papyrifera), and a large northward expansion for southern pines, as exemplified by 

loblolly pine (Pinus taeda). The significance here is that there is an expected shift away 

from prime ALB host trees in the future.

A recent case study of impacts on Vermont forests is particularly instructive of the degree 

of on-going and already visible changes within the current geographic reach of ALB. 

Wilmont (2011) notes that climate changes are already clearly evident in in the State. 

Temperatures have increased in the larger Northeast region by 1.8F (1.0C) since 1970, 

with winter temperatures rising faster than summer temperatures. Precipitation has 

increased by 15-20% over the past 50 years with 67% of this now falling in heavy 

precipitation events. These and other medium-term trends in climate are anticipated to 

affect Vermont’s forests, including: 

• More frequent hot (over 90o

F), humid days; 

Appendix D. Climate Change Impacts Related to ALB
• Longer growing seasons; 

• Worsening of air quality in areas where air quality problems already exist; 

• Increased heavy downpours; 

• More frequent winter thaws and earlier springs; 

• Less winter precipitation falling as snow and more as rain; 

• Earlier spring snowmelt resulting in earlier peak river flows; and, 

• More frequent short-term droughts in late summer and fall.

Species distribution has shifted at high elevations in Vermont in the past 40 years. 

Northern hardwood trees are now able to survive at increasing elevations due to 

moderating temperatures, outcompeting spruce and fir trees which themselves are 

increasingly vulnerable to warming. Only slightly less vulnerable are northern hardwood 

forests whose dominant species are sugar maple, yellow birch and American beech. 

These forests are expected to be nearly eliminated in Vermont, replaced by species that 

prefer the warmer drier conditions, such as oak and pine species (Karl et al, 2009). Trees 

stressed from low water availability tend to reduce their defense mechanisms and are 

more susceptible to insect or disease invasion. Currently, three non-native pests are 

expanding across Vermont forests, with the potential to severely impact hemlock, ash, 

and maple species (Wilmont, 2011).

Indirect impact of climate change on host trees and on vegetation. Elsewhere, such as in 

Britain, surveys of forest tree condition illustrate correlations between drought years and 

tree crown defoliation as drought, combined with high temperature induces stress in trees 

and thereby predisposes them to attacks by pests and pathogens. Such stresses are likely 

to be most intensely felt by street trees because of the ‘heat island effect’ and also 

because urban trees are often planted in suboptimal conditions with little area for root 

expansion and frequent root disturbance from utilities operations. This stress is often 

found to increase susceptibility to insect pests although evidence is more limited or at 

least variable, when it comes to pathogens. Changes in the plants’ environment have the 

capacity to alter their palatability to pests, as they can change the way in which plants 

allocate available resources to growth or defense. For example, increased CO2 levels can 

make plants more palatable to some pest species through increases in soluble 

carbohydrates within phloem tissue (Tubby and Webber 2010).

(b) Direct impact of climate change on Asian longhorned beetle. We anticipate that ALB 

and other insects will be strongly impacted by projected levels of global (and local) 

warming. Writ-large, predicted climate changes are likely to increase developmental rates 

and reduce winter mortality for many insects, leading to multi-voltinism in some species. 

The increased number of generations per year will also enable pests to evolve and adapt 

much more effectively to climatic change than their tree hosts, through enhanced 

dispersal as well as phenotypic and genotypic plasticity. 

Prior to Bebber et al (2013), the extent to which crop pests and pathogens alter their 

latitudinal ranges in response to global warming was largely unknown. Using CABI 

(Centre for Agriculture and Biosciences International) data on a diverse array of 612 crop 

pests and pathogens worldwide, they demonstrate an average pole-ward shift of 2.7 +/-

0.8 km / year since 1960, but with significant variation in trends among taxonomic 

Appendix D. Climate Change Impacts Related to ALB
groups. Insect pests are strongly influenced: warming generally stimulates insect 

herbivory at higher latitudes, primarily through increased winter survival; rainfall has 

also an obvious effect, with defoliating insects responding negatively to drought and 

borers positively. The observed pole-ward shift in many taxa support the hypothesis that 

global warming-driven pest movement is already underway.

Because of their generally short life-cycles, great reproductive potential, sensitivity to 

changes in temperature and, in many cases, great capacity for dispersal, even moderate 

changes in climate have already had significant rapid impacts on the distribution and 

abundance of many pests and pathogens. Climate change will also affect pest vectors, 

parasites and natural enemies. Native pests, some not currently perceived as problematic, 

may become more damaging. In comparison to insects, trees are very long-lived and will 

only be able to adapt much more slowly to changes in their local environment. 

Potentially, this makes them more vulnerable to the rapidly moving and changing 

organisms around them.

There are few studies on the effect climate change will have on ALB in North America. 

On the other hand, there are several comprehensive laboratory studies of temperature and 

humidity impacts on the species’ reproduction by Keena and colleagues (Keena, 2006; 

2009; Keena and Moore, 2010; Sanchez and Keena, 2013); these provide much insight 

into the insect’s likely response to warming conditions. 

At an early point in her ALB research, Keena (2006) noted there was a critical need for 

information on the basic biology of the ALB. Accurate data and models are seen as 

essential underpinnings for scientifically predicting the insect’s development – with the 

management goals of optimizing exclusion and eradication treatments and predicting 

spread rates under different environmental conditions. Detailed studies followed on 

individuals from Bayside, NY and Ravenswood, IL to assess temperature effects on 

developmental rates and survival over a wide temperature range -- from 10°C (larvae 

only), 15°C, 20°C, 25°C, 30°C (egg and larvae only) to 35°C (larvae only). 

Keena and colleagues (Keena, 2006; 2009; Keena and Moore, 2010; Sanchez and Keena,

2013) found:

x a nearly linear relationship exists between developmental rate of ALB eggs and 

temperatures between 15°C and 30°C. Using this relationship, they predict that eggs 

would not hatch at temperatures of 10°C or less. Based on the lower percentage hatch 

of viable eggs at 30°C compared to 25°C, the upper temperature at which egg 

development ceases and eggs die is at or above 35°C.

x defining lower and upper temperature limits are essential to accurate modeling. The 

minimum developmental threshold for instars 1 to 8 is close to 10°C. There is some 

development at 10°C, at least for early instars; about 20 percent of the larvae will 

molt to the second instar after about 5 months. The upper threshold at which 

development stops and death occurs, is probably between 35 and 40°C. Larval 

survival was higher at 25°C than at lower temperatures and was zero for 35°C by the 

Appendix D. Climate Change Impacts Related to ALB
beginning of the fifth instar. Larvae held at 15°C, 30°C, and 35°C had narrower head 

capsules and weighed less than those held at 20°C or 25°C from the third instar. 

x temperature response depended on ALB provenance. Bayside NY females laid fewer 

eggs at both 20°C and 25°C than Chicago IL females. The percentage of eggs that 

were viable did not vary between temperatures or strains. The Chicago IL larvae 

gained weight faster than those from Bayside NY in later instars. Temperature and its 

influence on larval weight had profound impacts on whether a larva proceeded to 

pupation.

x there is no significant difference in female longevity between populations of the two 

provenances or temperatures. Males tended to lived longer than females at all 

temperatures and lived longer at 20°C than 15°C or 25°C. The time the females began 

laying eggs and the order of average number of eggs laid was significant: 25°C > 

20°C > 15°C. 

x the estimated lower threshold temperature for development of instars 1-5 and the 

pupal stage was near 10C and was near 12C for the higher instars. Developmental 

rate was less temperature sensitive for instars 5-9 compared with instars 1-4.

Development for all but the first instar was inhibited at constant temperatures at about 

30C, and all instars failed to develop at 40C.

x differences in humidity shorten adult longevity, especially at low and high 

temperatures. Hence, caution should be used in applying predictions based only on

temperature relationships developed in the laboratory to field conditions. Moreover, 

the beetle’s ability to seek out locations with optimum temperatures (e.g., sunny 

perches when it is too cool and shady locations when it is hot) may lessen the adverse

effects in both the summer and fall; at least 2o

C should be added to air temperatures 

to adjust for the mediation of temperature by the wood.

In summary, temperature has significant impact on all life history parameters (esp. female 

fecundity, longevity) assessed and comparable with that Zhou et al (1984) found for A. 

glabripennis (form nobilis) adults in China. Straightforward mathematical relationships 

greatly facilitate development of predictions of potential geographic range that are essential 

for effective control and eradication efforts. Current summer temperatures throughout most 

of the lower 48 states should support ALB survival and reproduction. Given ALB survival is 

brief where summer temperatures for a full day exceed 30o

C, continued future warming may 

adversely impact on the beetle’s vigor and establishment in specific regions of the country.

Indirect impact of climate change on Asian long-horn beetle. The level of uncertainty 

regarding specific climate change impacts makes planning more challenging. The potential 

implications of this for ALB management cannot be understated. Forest-specific strategies 

for climate change adaptation are now urgently needed to inform management plans. Most 

cities and many natural forests across the northeast US and southeast Canada face threats 

from multiple insect pests; many of the most difficult to manage are exotic invasives that 

have no or few indigenous biological enemies. In addition to ALB, emerald ash borer (EAB), 

Appendix D. Climate Change Impacts Related to ALB
gypsy moth (GM) and Dutch elm disease (DED) pose significant threats and are being 

monitored closely as part of control programs to slow widespread damage (Nowak et al,

2010; Toronto, 2007). Climate change is already having an impact by increasing the severity 

of outbreaks by these pests. This increases greatly the costs of their control, as well as raises 

the need for and expenditures on tree replacement and for programs designed to maintain tree 

health. A high premium is placed on strategic management of urban forests and pests to 

maintain and expand tree cover. Under warming conditions and enhanced needs for pest 

control efforts, there is increasingly less leeway for delay and discretionary management 

action. 

It is now clear that ALB and other exotic pests are having sizable impact on urban trees. For 

example, in Chicago, ALB could potentially cause losses to the urban forest of $1.3 billion in 

structural value (53.6 percent of live tree population), GM $595 million of losses (19% of all 

trees), EAB $295 million (12% of all trees) and DED, an additional $31 million (5.5 % of all 

trees). In Toronto, ALB discovered in 2003 can affect 43% of the City’s tree population and 

potentially cause structural losses estimated at $4 billion. Over the 1930-1950 period, DED 

killed as many as one-third to half of all City trees and could kill an additional 1.6% ($279 

million); current outbreaks of GM and EAB threaten an additional 24% of the tree population 

($2.1 billion structural value). One result (compounded by urban conversions) is that 

adequate tree cover in ALB-infested cities is difficult to maintain. Toronto’s tree cover 

diminished 7% over the 1985-2005 period -- in spite of accelerated tree re-planting programs. 

Tree diversity is now less and vulnerability greater as individual species are selectively killed 

in successive pest outbreaks (Toronto 2007). In New Your City, ALB represents a potential 

loss to urban forest of $2.25 billion in structural value (43.1% of the tree population); GM 

could potentially kill 23% of all trees ($2.21 billion loss); EAB 0.5% of all trees ($9.8 

million loss), and DED an additional 0.7% of all trees ($111 million loss).

A recommended tree cover target is an average of 40% canopy cover -- to ensure the 

sustainability of the urban forest and maximize the ecological, social and economic benefits 

derived from urban trees (American Forests 2007). Using this standard, Baltimore, Chicago, 

New York City and Toronto require increases of 16%, 23%, 20% and 20%, respectively, to 

attain the tree cover target (Nowak et al 2007, 2010, Toronto 2007). A tabulation of percent 

tree cover in 17 North American cities shows a range of 7% to 37%, with an average of about 

25% (Nowak et al 2010) suggesting considerable room to expand urban tree cover to capture 

the benefits of CO2 sequestration, carbon storage and environmental benefits as climate 

changes.

In summary, the nexus of climate change and the presence of ALB and other exotic pests is 

greatly increasing the demand for concerted management for tree health and sustainability of 

urban and adjacent natural forests.

2.2.2 Direct and indirect impact of ALB eradication project on climate change

Direct Impacts of eradication project on climate change. The most conspicuous impact of the 

removal of large numbers of ALB-infested trees is the loss of CO2 sequestration and release 

of carbon storage in trees and soil. Our estimates indicate that across the northeast US about 

Appendix D. Climate Change Impacts Related to ALB
120,000 trees have been removed and chipped, releasing a total of 20,000 mt of CO2 to the 

atmosphere since Year 2000. At risk over the five affected States is an estimated 2.4 million 

mt of CO2 release from host trees (Table 1). 

If left to regenerate or if artificially replanted, the amount of CO2 released upon removal 

would be sequestered in new growth over an interval of 76 years on average (or less, if 

warming generally accelerates tree growth). A potential benefit is the removal of older 

infested trees. This assumes old trees more vulnerable than young age classes to disease and 

to damaging weather events (e.g., wind, snow, icing, drought), and are slower growing. 

Indirect Impacts of eradication project on climate change. Tree removal under current ALB 

eradication programs serves to expand and exacerbate the impacts of climate change as we 

understand them. Below, we identify three categories of impacts where tree removal feeds 

back to exaggerate/exacerbate the on-going GHGs linked to global climate warming and 

attendant increases in extreme weather variations.

(1) In urban areas, where trees now shade buildings, tree removal under ALB eradication 

will increase energy requirements and emissions of GHG from power plants -- to 

compensate for increased heating in winter and air conditioning in summer. 

Based on average state energy costs in February 2009, trees in Chicago are estimated 

to reduce energy costs from residential buildings by $360,000 annually. Trees are 

estimated to slightly increase the amount of carbon released by fossil-fuel based 

power plants. However, this estimated increase in emissions (1,200 tons) is more than 

offset by annual carbon sequestration by trees (25,200 tons) (Nowak et al 2010). 

Trees in Toronto are estimated to reduce energy costs from residential buildings by 

$9.7 million annually. Trees also provide an additional $483,000 CND in value per 

year by reducing the amount of carbon released by fossil-fuel based power plants, 

representing a reduction of 17,000 mt of carbon emissions. These values could be 

increased through more strategic tree planting to maximize the potential energy 

effects of trees (Toronto, 2007). In New Your City, the energy and cost savings are 

even greater. Trees there are estimated to reduce energy costs from residential 

buildings by $11.2 million annually based on 2002 energy costs. Trees also provide 

an additional $167,000 in value per year by reducing the amount of carbon released 

by the City’s fossil-fuel based power plants (a net reduction of 9,100 tons of carbon 

emissions) (Nowak et al., 2007).

(2) Reduced tree cover typically results in loss of storm-water regulation and flood

moderation. A single, average- size tree (21 m height) evapo-transpires 10-200 liters 

water per day or about 2000-40000 liters per year per tree, pending tree species and 

climate conditions (Wullschleger et al., 1997). Trees also lessen soil erosion and 

nutrient loss to streams and ground water. For example, of total annual precipitation, 

the combination of canopy interception, surface evaporation and transpiration loss is 

estimated to be 40-64% in deciduous broadleaf forests and 55-80% in confers forests 

in the UK (Nisbet, 2005). Hence, trees exert a powerful modulating influence on 

water dynamics and this function is put at risk as tree cover is diminished.

Appendix D. Climate Change Impacts Related to ALB
(3) By removing significant levels of air pollutants, urban trees and forests improve local

air quality in five main ways (Nowak et al., 2007; 2010; Toronto, 2007), namely by:

• absorbing gaseous pollutants through leaf surfaces, including ozone (O3) and 

nitrogen dioxide (NO2)

• intercepting particulate matter (e.g., dust, ash, dirt, pollen, smoke)

• reducing emissions from power generation for heating and cooling of buildings

• releasing oxygen through photosynthesis

• transpiring water and shading surfaces, lowing local air temperatures, and thereby 

reducing O3 levels.

Not all gases above are GHGs but in total and across the composite of urban areas, 

these do affect local and regional climates (e.g., heat island effect) and ultimately 

feed-back variously to the global warming phenomenon. Although trees do emit 

volatile organic compounds (VOCs) that can contribute to ozone formation, 

integrative studies have revealed that an increase in tree cover actually leads to 

reduced ozone formation (Toronto, 2007). 

In Chicago trees remove an estimated 888 tons of air pollution (CO, NO2,O3, PM10, 

SO2) per year with an associated value of $6.4 million (Nowak et al., 2010). In 

Toronto trees and shrubs remove an estimated 1,430 mt of the same air pollutants per 

year, with an associated value of $16.1 million (Toronto 2007). In New York City, 

removal is estimated at 2,202 tons/year with an associated value of $10.6 million/year 

(Nowak et al., 2007).

2.2.3 Manifestation of evident/known impacts of global climate change in 

geographic area

Keena and colleagues (Keena, 2006; 2009; Keena and Moore, 2010; Sanchez and Keena,

2013) demonstrate that climate has a strong impact on ALB growth and survival. Hence, the 

question -- what actual evidence is available to demonstrate impacts on ALB populations 

have occurred already and continue to occur as a result of global climate change?

Long-term shifts recorded for average temperature and total precipitation at Cincinnati, Ohio 

are both modest, highly variable, and may be cyclical in nature (Fig. 2a, 2b) (NCDC, 2013).

Long-term air temperature records for southwestern Ohio (NOAA Zone 8) indicate an 

increase of 0.42C / 100 years over the 1895 through 2013 period. This magnitude is modest 

relative to global temperature change, estimated to be 0.73C / 100 years (Attachment 3).

Appendix D. Climate Change Impacts Related to ALB
Figure 2. Yearly (a) average air temperature and (b) average total precipitation in NOAA’s 

meteorological station at Cincinnati’s Lunken Field airport. Linear and 4th order 

polynomial regression trends and equations shown. Data obtained from 

http://www.esrl.noaa.gov/psd/data/timeseries/ (accessed 11/6/2013) includes observations 

of January 1895 through October 2013.

A simple model of the ‘favorability’ of daily weather conditions, May through October over 

the 1950 – 2013 period was developed using Keena (2009) observations on ALB response to 

temperature and humidity conditions. The ALB Climatic Favorability Index is the sum of 

daily average temperatures 10 C to 33 C, minus the sum of temperature <10 C and > 32C, 

multiplied by the sum of total precipitation > 0 mm, an calibrated on a scale of 0-100 by 

dividing by 10,000,000. 

The Index is dominated by a cyclic pattern. Based on the linear regression, there is a decrease 

of 0.95 index points (or 1.6 % per 100 years) relative to 1950. Since first detection on wood 

packaging material arriving from China in 1996, six years, (1996, 2000, 2001, 2003, 2004, 

2009) stand out as particularly favorable for ALB growth (i.e., >17.5 Index); this contrasts to 

any earlier 18-year period which had two to three such events over 18 years. Six years were 

relatively unfavorable (<7.5) over the 1996-2013 interval (Fig. 3). These Index values 

Appendix D. Climate Change Impacts Related to ALB
suggest an overall static trend but one punctuated by especially favorable or adverse yearly 

conditions. It is noteworthy that the present outbreak in Clermont County Ohio was preceded 

by a five year interval (2000-2004) of favorable climate for ALB, with the one exception of 

2002.

In brief, our analysis shows moderate temperature and precipitation shifts long-term in the 

southwest Ohio zone, consistent with but more moderate than global trends (Attachment 3). 

Our Index of climatic suitability for ALB shows both favorable and adverse years occur on a 

frequency of about 1.4 and 2.0 per decade, respectively, but with virtually no overall trend 

since 1950. Cyclical patterns are conspicuous in all trends, implying a need for caution in 

stating definitively there is clear evidence of impact of global climate change on geographic 

area. Outbreak sites on the Great Lakes (Chicago, Toronto), the Atlantic Ocean (Worcester, 

Boston, New York City, Jersey City) and the Ohio River Valley (Cincinnati) imply that ALB 

thrives within a ‘humidity corridor’ and that commonly applied degree-day models require 

revision to fully incorporate moisture parameters. 

Figure 3. Daily estimate of favorability of climate for ALB survival and growth in 

Cincinnati, OH. ALB Climatic Favorability Index based on Keena et al (Keena, 2006; 

2009; Keena and Moore, 2010; Sanchez and Keena, 2013) temperature and precipitation 

thresholds. Daily maximum and minimum air temperature and daily total precipitation 

January 1950 through October 2013 observed at Cincinnati Lunken FAA AP, OH, Station 

1916 (http://www.esrl.noaa .gov/psd/cgi-bin/data/timeseries/ accessed 11/6/2013). Dashed 

line is linear regression of the Index trend.

3.0 Alternatives

3.1 No Action Alternative 

Appendix D. Climate Change Impacts Related to ALB
We posit the question of what would be the impact on CO2 release under hypothetical conditions 

in which there was no ALB eradication effort. Keena and Moore (2010) concluded that climatic 

conditions are suitable for ALB establishment and survival in all contiguous 48 States. To 

estimate release US-wide, we use tree carbon estimates for urban areas in 48 States published by 

Nowak and Crane (2000) and convert their weights of C to metric tons (mt) of CO2 using the 

standard 3.67 conversion factor. 

We then assume a percentage of all trees in any State are ALB host tree species. The percent of 

all trees that were ALB host species was the percent basal area of trees in each State that were 

known host trees estimated by Nowak et al. (2003). Second, we estimated the forest area affected 

adjacent to each urban area. The fraction of trees in forest areas at the last two ALB eradication 

sites is 2.33-fold greater than that removed from those two urban areas. We use this conversion 

(vs. that for all five sites) on the consideration that these are more representative of on-going and 

near-future conditions (compared to the ALB locations early in 2000). Third, the CO2 released 

from soil (as in the main CO2 model) was estimated as 25% of that released from the urban and 

adjacent forest trees removed. Total potential CO2 release is the sum of that released from urban 

trees, forest trees, and soils.

This total was estimated for each of the 5 States with APHIS ALB eradication efforts to date. For 

comparison, we also estimate the total release for each of the 20 States in the Northeast plus 

North central regions, and for all 48 States (Attachment 4). 

Alternative 1a. In this alternative, only urban host trees and those in adjacent forests are 

involved. Estimates indicate that in the absence of ALB eradication there is a potential release of 

CO2 of 478 million mt in the five States, 2,111 million mt from the twenty Northeast plus North 

central States, and 2,255 million mt for all forty-eight States. These estimates represent potential 

releases under tree removal methods standardly used to date to eradication ALB found in and 

adjacent to city areas. 

Alternative 1b. Urban forest area is only 3.5% of US total area on average; even with the 

addition of adjacent forest areas (2.33 x that of the urban trees), the area involved is only 11.7% 

of total. Using the same hypothetical approach and assumptions as above but involving all host 

trees in the landscape (not just those in urban and adjacent areas), the estimated potential releases 

are two to six-fold larger (Attachment 5). Potential release of CO2 is estimated to be 1,030 

million mt in the five States, 6,959 million mt from the twenty Northeast plus North central 

States, and 13,906 million mt for all forty-eight States. 

3.2 Preferred Alternative

We posit several alternative CO2 management scenarios to achieve enhanced carbon storage and 

sequestration rates in trees. Two of these, increased tree health and expanded tree cover were 

identified as obvious opportunities in urban tree studies, notably those of Nowak et al (2007, 

2010) and the City of Toronto (Toronto 2007). The fact that soils typically contain significant 

quantities of carbon, their treatment during and after eradication efforts also merits attention.

Appendix D. Climate Change Impacts Related to ALB
(1) Tree Health. Under programs of active urban tree and forest management, there is an 

opportunity for replacing trees removed and some of the current trees in poor or declining 

health with tree species resistant to ALB, and at the same time, better adapted to enhanced 

warming and climate variability. Beyond this are opportunities to increase tree protection 

from pests and improve growth of urban trees, thereby increasing CO2 sequestration and 

storage. 

The fraction of urban trees in unhealthy condition is notable. For example, an urban forest 

health survey across 20 Northeast and North central States found only 23% of all trees were 

in good (22%) to excellent (1%) condition. The remaining 77% ranged from fair (27%), to 

poor (16%), or declining (12%) and otherwise improving and variable condition (18%, and 

4% ‘other’) (Pokorny, 1998) (http://www.na.fs.fed.us/spfo/pubs/uf/survey/execsum.htm 

accessed 11 08 2013).

(2) Tree Cover. Recent surveys over urban areas in the US (and Canada) show the percent in 

tree cover is a fraction of what the American Forests (2007) recommends as adequate. 

Compared to their standard of 40% tree cover, the average over 20 cities was 23.0%. The 

large five cities with active tree planting programs (Baltimore, Boston, Chicago, New York 

City, Toronto) had an average of 20.4% and could benefit by doubling their tree cover 

(Nowak et al., 2010). Re-planting can be difficult to achieve; many US cites over the past 

decade in fact show increased conversion to building, roads and other infrastructure, hence a 

relative decrease in urban tree cover (Nowak and Greenfield, 2012). 

(3) Soil Disturbance. Impacts of tree removal operations on soil surface disturbance are 

unreported in the ALB data and remain a large uncertainty in our GHG estimates. 

We posit two tree management scenarios designed to address the issues of sub-optimal tree 

health and sub-par total percent urban area in tree cover. Details of our procedure are 

documented in Attachment 8.

In the first case, we run the CO2 Emissions and Sequestration Model to estimate the effect that a 

continuous increased tree growth rate of 10% would have on the number of years to 

compensation point (i.e., total sequestration in new growth = total emission from removed trees), 

and on the magnitude of additional CO2 sequestration. We consider ten percent is conservative 

considering that three-quarters of all trees are in fair, poor or worst condition. We assumed that 

better silviculture and protection against pests will be part of the effort to ensure the enhanced 

growth is sustained. 

The current Ohio eradication site was used to demonstrate what could be achieved in an actual 

operation. This alternative (Scenario 2) to a ‘business-as-usual’ approach (Scenario 1) shortened 

the compensation time by only two years but resulted in an additional 330 mt of CO2 capture 

(Fig. 4, Table 2).

The Ohio eradication site was also used to estimate the additional CO2 sequestered in a 

hypothetical expansion of tree cover. We assumed an urban tree cover of 25% at the Ohio site 

and increased this 1.6-fold to attain the American Forests (2007) standard of 40% (Scenario 3), 

Appendix D. Climate Change Impacts Related to ALB
while still ensuring the better silviculture that is part of Scenario 2. The compensation point was 

reached in 43 years -- or in about half the time of the ‘business as usual’ scenario (Scenario 1). 

The additional CO2 captured by year 85 at the peak of tree growth was significant. Fully1471 mt 

more CO2 was sequestered and stored, or twice that in the ‘business as usual’ case (Fig. 4, Table 

2).

Clearly, there is considerable discretionary leeway to improve the sequestration and capture of 

CO2 through active management of tree populations in the post-eradication period. Further gains 

can be made by reducing soil disturbance and by ensuring adequate or improved soil drainage 

properties. 

Figure 4. Estimates of CO2 sequestration in new tree growth and dynamic of CO2 net flux 

under alternative management options of the Ohio eradication site. Scenario 1 is business 

as usual. Scenario 2 is management for 10% increased tree growth rate with improved 

silviculture and pest protection. Scenario 3 is a 1.6-fold expansion of tree cover while 

maintaining enhanced tree growth and protection. Dashed blue line aids in visualizing 

timing of compensation points (total sequestration = total emissions) of each scenario.

Appendix D. Climate Change Impacts Related to ALB
Table 2. Three alternative ALB post-eradication alternatives for management of tree CO2

sequestration and other benefits. Scenario 1 is 'business-as-usual'. Scenario 2 is 

management for a continuous 10% acceleration of tree growth, while maintaining enhanced 

tree protection. Scenario 3 is urban tree cover expanded from 25% to 40% together with 

enhanced tree growth and protection. Years to achieve compensation, peak CO2

sequestration level, and gain in total CO2 over 'business as usual' are given.

4.0 Mitigation Measures 

4.1 Reduction of GHG Emissions and Environmental Impacts

The President’s Council on Environmental Quality (CEQ) directs agencies to consider and 

evaluate reasonable alternatives to proposals (Title 40, Code of Federal Regulation, Part 1502.14 

(40 CFR 1502.14)). Alternatives proposed to address climate change issues need to be relevant to 

the proposed action’s purpose and need as well as technically and scientifically feasible. 

Alternatives may include mitigation measures to reduce GHG emissions, affect carbon cycling, 

or enhance adaptive capacity. Alternatives developed to respond to climate change issues should 

clearly relate to the cause-effect relationship between the proposal and climate change and have 

meaningfully different climate change-related effects when compared to the proposal and other 

alternatives.

4.1.1 Project design to minimize GHG emissions and environmental impacts 

ALB eradication approaches will continue to require removal of trees (and pesticide 

injections) as applied in current methods. The newly introduced regulations on climate 

change require attention to details of how to minimize release of carbon stored in trees, how 

to maximize CO2 sequestration in the post-removal period, and enhance climate adaptation. 

A comparison of scenarios assessed in this study indicate large emissions in the unlikely 

event of no action to achieve eradication nation-wide. Alternatively, there is considerable 

management leeway to increase the rates of tree regeneration post-removal and expand tree 

cover to levels exceeding pre-treatment (Fig. 5).

Appendix D. Climate Change Impacts Related to ALB
Figure 5. Summary of CO2 emissions under ‘No Action’ Alternative 1 and ‘Enhanced 

Action’ Alternative 2. (a) Alternative 1b is extreme case where all host trees in US are 

killed; Alternative 1a is case where only urban and adjacent forest host trees are killed by 

ALB. (b) Alternative 2 is case where CO2 emissions and sequestration of ‘business-asusual’ (Scenario 1) is compared with 10% accelerated growth (Scenario 2), and accelerated 

growth plus expanded tree cover (Scenario 3) (see Table 2).

4.1.2 Operational changes 

Two significant changes in ALB eradication efforts could significantly improve the efficacy 

of the ALB Eradication Project nationwide. The first is to enhance the surveillance efforts to 

find ALB early through improved surveillance technology. This could include models of 

especially high-risk years and locales through the development of GIS-based maps (e.g., 

Nowak et al., 2003; Kalaris and Crane, 2013) coupled with routinely updated models of 

ALB climate suitability. Identified “hotspots” based on the most recent climate data could be 

the focus of intensive field detection surveys. Second, data collection during tree removal in 

the future could include the records of tree species, tree diameter, soil type and degree of soil 

disturbance following tree removal. These data would then be used in refining the current 

approach and model precision. 

4.1.3 Compensatory measures

The removal of infected and high-risk trees will result in emissions of CO2 (and possibly 

other GHG such as NOx) that feed into the global levels of GHG in the atmosphere. Our 

analyses show there are two main “offsets” that compensate for these initial emissions. 

First, there is recapture of emitted carbon through natural tree regeneration; beyond this, 

enhanced tree management options that can capture all and even more than the total CO2

accelerated 

growth and 

expanded

tree cover

Appendix D. Climate Change Impacts Related to ALB
released. Practical and economically feasible silviculture programs can be designed to both 

accelerate the rate of CO2 capture by regenerating trees and exceed initial loss levels. 

Second, tree cover expansion and continuing tree protection provide numerous advantages of 

climatic adaptation for urban areas, with measureable human benefits. Payoffs include 

reduced energy consumption, moderation and/or capture of air pollutants, improved stormwater management, and the presence of shade trees. Adding a strong diversity of tree species 

is important given successive waves of mortality by exotic pests in the past, and their 

continuing introduction and establishment (Aukema et al., 2010)

In addition to the cities frequently referred to in this report (Chicago, New York City, 

Toronto), other cities in the Northeast have active tree expansion programs in progress, such 

as Boston (http://www. growbostongreener.org/gbg/ accessed 11/05/2013) and Baltimore 

(http://www.baltimoretreetrust.org/ accessed 11/05/2013). These urban programs provide 

insight into the practicality and cost advantages of on-going operations and the many added 

human benefits from increased tree cover in urban areas.

5.0 References

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Greenhouse Gas Emissions. February 18, 2010 Release, Council on Environmental Quality. 

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Melillo and R.G. Lathrop. 1995. Predicting the effects of climate change on water yield and 

forest production in the northeastern United States. Clim. Res. 5: 205-222.

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American Forests 2007. Urban tree cover forty percent standard. 

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Arthur, M.A., L.M. Tritton, and T.J. Fahey. 1992. Dead bole mass and nutrients remaining 23 

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Aukema, J.E., D.G. McCullough, B. Von Holle, A.M. Liebhold, K. Britton and S.J. Frankel.

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BioScience 60: 886-897.

Appendix D. Climate Change Impacts Related to ALB
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polewards in a warming world. Nature Climate Change, Advance Online Publication 

www.nature.com/natureclimate change doi: 10.1038/nclimate1990. 

Christopher, S.F., M.J. Mitchell, M.R. McHale, E.W. Boyer, and D.A. Burns. 2008. Factors 

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Dale, V.H. and S.C. Beyeler. 2001. Challenges in the development and use of ecological 

indicators. Ecological Indicators 1:3-10..

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Appendix D. Climate Change Impacts Related to ALB
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Longhorned Beetle. Northern Research Station, USDA Forest Service. Syracuse, New York. 

(http://www.nrs.fs.fed.us /disturbance/invasive_species/alb/localresources/docs/ALB_potential.pdf accessed 11/13/2013)

Nowak, D.J., R.E. Hoehn, D.E. Crane, J.C. Stevens, and C. Leblanc Fisher. 2010. Assessing 

urban forest effects and values, Chicago’s urban forest. Resour. Bull. NRS-37. Newtown Square, 

PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 27 p. 

http://www.itreetools.org/resources/ reports/ Chicago's%20Urban%20Forest.pdf

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forest effects and values, New York City’s urban forest. Resour. Bull. NRS-9. Newtown Square, 

PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 22 p.

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Appendix D. Climate Change Impacts Related to ALB
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Appendix D. Climate Change Impacts Related to ALB
Attachments

Attachment 1

Major elements, sources of data and assumptions used in development of the CO2 Emissions and 

Sequestration Model.

Trees Removed number of trees removed at each of five ALB Eradication Program sites

Percent Urban percent of all trees in urban area and in forest area for each of five sites

Tree Volumes total tree volume, including roots, trunks, branches, leaves estimated using 

tree species equations of USDA Forest Service COLE Program 

(http://www. ncasi2.org/COLE/), using ‘Individual Tree Spreadsheets’ 

option. Algorithm requires number of trees of selected tree species by 

diameter (dbh) class, tree age of dbh class, tree height of dbh class, and 

tree specific equation. Tree age and height estimates are the same as those 

of Nowak et al (2010). The example below is for sugar maple in urban 

areas:

Tree Species Three tree species are selected to represent a range of coefficient b for tree 

volume representative of northern hardwoods, namely sugar or “hard” 

Appendix D. Climate Change Impacts Related to ALB
maple, red maple, and silver or “soft” maple. Tree species are not 

recorded for tree removals on eradication sites (Attachment 1).

Urban and Forest Tree diameter (dbh) and tree heights differ between urban and forestgrown trees such that separate equations are used. 

Tree Dry Weights tree volume converted to tree dry weight using coefficient b (above) of 

each tree species. Total dry weight of each tree component (e.g., foliage) 

for each dbh size class is summed to calculate total tree dry weight. For 

example, calculations for sugar maple in urban areas:

Tree and Soil CO2 conversion factors are used to estimate CO2 levels from estimates of dry 

weights. Nowak et al (2010) use 0.8 to calibrate for urban trees that 

typically have less biomass than predicted by forest-derived biomass 

equations. The species carbon factor (0.5) is the carbon content of wood, 

converted to CO2 content using the standard 3.67coefficient. The total 

carbon at soil surface in urban areas is obtained from Pouyat et al (1997). 

Soil carbon exposed is a fraction of the crown leaf area (above); this is 

multiplied by an assumed exposure factor (5%) likely once the tree canopy 

is removed. The total soil CO2 release is product of the three prior terms. 

Total CO2 is the sum of the tree and soil carbon. All US units are then 

standardized in metric tons (mt). 

Appendix D. Climate Change Impacts Related to ALB
CO2 Emission The rate of decomposition and release of CO2 to atmosphere from chipped 

wood following tree removal are based on those for deciduous hardwood 

tree species studied in the Northeast US (e.g., Arthur et al 1992 at 

Hubbard Brook NH). Assumption is made that chipping wood of large 

boles does not significantly alter natural decomposition rate. Example of 

CO2 emission from decomposition of bole wood is shown below.

Appendix D. Climate Change Impacts Related to ALB
Attachment 2

Coordinates of Cincinnati, OH US Meteorological Station, website and types of data accessed

used in models of ALB Climatic Favorability Index for Alternative 2 evaluations.

Latitude: 39° 14' 27" N (deg min sec), 39.2408° (decimal), 3914.45N (LORAN)

Longitude: 84° 29' 58" W (deg min sec), -84.4995° (decimal), 08429.97W (LORAN)

Elevation: 245 meters (804 feet) validated against 244 meters (799 feet) from NED 

Contiguous US 1/3E arc second elevation data

Location: Cincinnati, OH US

County: Hamilton, OH

GHCND: USW00093812 Cincinnati Municipal Airport Lunken Field, Oh US

Website: http://www1.ncdc.noaa.gov/

Data Types: TMAX - Maximum temperature (tenths of degrees C)

TMIN - Minimum temperature (tenths of degrees C)

PRCP - Precipitation (tenths of mm)

Cincinnati, OH

Appendix D. Climate Change Impacts Related to ALB
Attachment 3

Comparison of trend in global mean temperature, 1880-2013, (http://data.giss.nasa.gov 

/gistemp/tabledata/GLB.Ts.txt accessed 11/13/2013) with that of southwest Ohio, Zone 8, 1895-

2013 (http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt accessed 11/6/2013).

Dark trend lines are 11-point moving averages.

Appendix D. Climate Change Impacts Related to ALB
Attachment 4

Estimate of CO2 release across US 48 contiguous States under Alternative 1 (no action).

Assumes full mortality of host tree species in urban and adjacent forests. Metric tons (mt) 

of carbon of urban areas in each State from Nowak and Crane (2002). Conversion to tons 

CO2 based on 3.67 carbon: carbon dioxide ratio. CO2 released in adjacent forest areas 

based on a multiplier of 2.33 (see text for details). CO2 released from soils is 25% of total 

CO2 release from urban plus forest trees. Estimates are total tree plus soil CO2 release in 

each 48 State, in 20 Northeast and Northcentral States (USDA Forest Service Region 9) 

and in the 5 States to date with ALB Eradication Programs.

Appendix D. Climate Change Impacts Related to ALB
Attachment 5

Extreme estimate of CO2 release from mortality of all host tree species across US 48 

contiguous States under Alternative 1 (no action). Same as in Attachment 6 except that all

host trees assumed to be killed (not just those in urban and adjacent forests).

Appendix D. Climate Change Impacts Related to ALB
Attachment 6

Assumptions used in runs of the CO2 Emissions and Sequestration Model to estimate levels of 

sequestration under the three scenarios of Alternative 2.

Scenario 1 all data and model algorithms as documented in Attachment 3 for ‘standard’ run 

of CO2 Emissions and Sequestration Model.

Scenario 2 initial total CO2 sequestration of Year 1 is compounded annually at rate of 0.10. 

This estimate of CO2 sequestration in accelerated growth is then added to total 

CO2 estimates of Scenario 1 standard run over full 100 year sequence post-tree 

removal by ALB Eradication Program.

Scenario 3 yearly estimates of total CO2 sequestration of Scenario 2 are multiplied by 15% 

increase over the extant 25% urban tree cover, or by 1.6. This provides an 

estimate of CO2 sequestration where total urban tree cover is 40% as 

recommended by standards for US cities (American Forests 2007).

Appendix D. Climate Change Impacts Related to ALB
Appendix E. Herbicide Human Health and Ecological 

Risk Assessment: Asian Longhorned 

Beetle Eradication Program

Appendix E. Herbicide Environmental Risk Assessment
Table of Contents

EXECUTIVE SUMMARY

1.0 INTRODUCTION

2.0 PROBLEM FORMULATION

2.1 Chemical Description and Product Use

2.2 Physical and Chemical Properties

2.3 Environmental Fate

2.4 Hazard Identification

2.4.1 Mechanism of Action and Pharmacokinetics

2.4.2 Acute Toxicity

2.4.3 Sub-Chronic/Chronic Toxicity

2.4.4 Carcinogenicity/Mutagenicity

2.4.5 Development and Reproductive Effects

2.4.6 Endocrine Effects

2.4.7 Potential Additive, Antagonistic, or Synergistic Effects

3.0. DOSE-RESPONSE ASSESSMENT

3.1 Human Health Dose-Response Assessment

3.1.1 Triclopyr

3.1.2 TCP

3.1.3 Imazapyr

3.1.4 Metsulfuron-Methyl

3.1.5 Drinking Water

3.2 Ecological Effects Analysis

3.2.1 Aquatic Effects Analysis

3.2.2 Terrestrial Effects Analysis

4.0 EXPOSURE ASSESSMENT

4.1 Human Health Exposure Assessment

4.1.1 Identification of Potentially Exposed Human Populations and Complete 

Exposure Pathways

4.1.2 Exposure Evaluation

4.2 Ecological Exposure Assessment

4.2.1 Aquatic Exposure Assessment

4.2.2 Terrestrial Exposure Assessment

5.0 RISK CHARACTERIZATION

5.1 Human Health

5.2 Aquatic and Terrestrial Ecological Risk Characterization

5.2.1 Aquatic

5.2.2 Terrestrial Wildlife and Domestic Animals

5.2.3 Terrestrial Invertebrates and Plants
6.0 UNCERTAINTIES AND CUMULATIVE IMPACTS

7.0 REFERENCES

ATTACHMENT A: Risk Estimations for Workers and General Public

Appendix E. Herbicide Environmental Risk Assessment
EXECUTIVE SUMMARY

The United States Department of Agriculture (USDA) Animal and Plant Health Inspection 

Service (APHIS) proposes to use the herbicides triclopyr or as a mixture using triclopyr, 

imazapyr, and metsulfuron-methyl to control sprouting vegetation from stumps that are host 

species for the Asian Longhorned Beetle (ALB). These herbicide treatments are needed as a way 

to prevent reinfestation of ALB-host trees that have been removed as part of the ALB 

Eradication Program. The preferred method of control for stumps is physical removal; however, 

in some cases, the use of herbicides is required. 

USDA APHIS evaluated the potential human health and ecological risks from the proposed use 

of triclopyr, imazapyr, and metsulfuron-methyl for the ALB Eradication Program. The risks to 

human health are expected to be negligible based on limited exposure from the proposed use 

pattern of these herbicides (hand painting and backpack spraying). Exposure is greatest for 

workers who will apply the product. The potential exposure for workers is low with the proper 

use of required protective equipment. The potential exposure for the general public is also 

minimal. Risks are quantified for workers and the general public to represent extreme exposure 

scenarios including accidental conditions. The conservative risk evaluation results show that the 

hazard index for workers and the general public do not exceed one (the USEPA level of 

concern), indicating that the exposure is unlikely to cause adverse health effects. Therefore, 

triclopyr and triclopyr mixed with imazapyr and metsulfuron-methyl used in the ALB 

Eradication Program should pose minimal risk to human health.

The risk of herbicide use to non-target fish and wildlife is also minimal. The proposed use 

pattern reduces potential exposure to most non-target fish and wildlife. Wild mammals and birds 

are at very low risk from herbicide applications due to the low toxicity of all three herbicides and 

the lack of anticipated effects to food sources that they use. Aquatic organisms are also at low 

risk based on the favorable toxicity profile for all three herbicides and expected residues that 

could occur in aquatic environments from the proposed applications. Non-target terrestrial 

plants are at the greatest risk from herbicide treatment; however, the method of application and 

selective use of herbicides as a treatment for stumps will reduce the risk to terrestrial plants.

1.0 INTRODUCTION

This human health risk assessment (HHRA) and ecological risk assessment (ERA) provides a

quantitative and qualitative evaluation of the potential risks and hazards to human health, 

nontarget fish, and wildlife from exposure to the herbicides triclopyr, imazapyr, and 

metsulfuron-methyl when used to control the regrowth of stumps of host species of the Asian 

Longhorned Beetle (ALB). 

The methods used in this HHRA to assess potential human health effects follow standard 

regulatory guidance and methodologies (NRC, 1983; USEPA, 2014a), and generally conform to 

other Federal agencies such as U.S. Environmental Protection Agency (USEPA), Office of 

Pesticide Programs (USEPA/OPP). The methods used in this ERA to assess potential ecological 

risk to nontarget fish and wildlife follow USEPA methodologies and other published 
methodologies with an emphasis on those used by USEPA/OPP in the pesticide registration 

process. 

The risk assessment is divided into four sections. The first is the problem formulation 

(identifying hazard), followed by the the effects analysis or dose-response assessment, and then 

the exposure analysis (identifying potentially exposed populations and determining potential 

exposure pathways for these populations). The fourth section of the risk assessment integrates 

the information from the exposure and effects analysis to characterize the risks to human health 

and the environment. In addition, the uncertainties associated with the risk assessment and 

potential cumulative impacts are discussed.

2.0 PROBLEM FORMULATION

APHIS is proposing the use of the herbicides triclopyr, or triclopyr mixed with imazapyr and 

metsulfuron-methyl to treat stumps and associated sprouts from host trees that were removed to 

prevent the further spread of ALB. When possible, APHIS will physically remove host trees 

along with the stumps to prevent reinfestation. However, physical removal of the stumps may 

not be possible in some situations such as when it is impractical to move stump removal 

equipment into an area, or there may be restrictions for habitat protection. In situations where 

stump removal is not feasible, APHIS will apply herbicides to treat the remaining stumps and 

associated sprouts.

Triclopyr is an herbicide that was first registered in 1979 (USEPA, 1998; USDA FS, 2011a). 

Triclopyr imitates a plant hormone (indoleacetic acid) classified as an auxin, and is used to 

control woody plants and broadleaf weeds (Cox, 2000). Imazapyr is an herbicide first registered 

in 1985 (USEPA, 2006). Imazapyr is an imidazolinone herbicide that inhibits acetohydroxyacid 

synthase, an enzyme involved in the biosynthesis of amino acids such as leucine, isoleucine and 

valine (HSDB, 2014b). Imazapyr is a systemic, non-selective, pre- and post-emergent herbicide 

that acts by inhibiting the synthesis of branched-chain amino acids in plants (USEPA, 2006). It 

is used for the control of a broad range of terrestrial and aquatic weeds. Metsulfuron-methyl is a 

sulfonylurea herbicide that inhibits the enzyme that catalyzes the biosynthesis of branched-chain 

amino acids (valine, leucine, and isoleucine) which are essential for plant growth (USDA FS, 

2011c). 

APHIS proposes the use of two triclopyr formulations for the treatment of stumps, Garlon® 3A 

and Pathfinder® II. Garlon® 3A contains the active ingredient triclopyr triethylamine salt (TEA). 

Pathfinder® II contains the active ingredient triclopyr butoxyethyl ester (BEE). Pathfinder® II 

allows more flexibility in being able to treat the bark instead of direct application to cut areas of 

the stem. In addition, APHIS is proposing some foliar applications of Garlon® 3A that will be 

mixed with two other herbicides. The active ingredients in these two other herbicides are 

imazapyr and metsulfuron-methyl in Arsenal® and Escort® XP, respectively. They will be used 

to treat sprouting foliage from stumps that are removed as part of the eradication efforts. All 

applications will be made either by hand painting undiluted material on the stump or directly 

spraying stumps and/or sprouting foliage using a backpack sprayer. 

Appendix E. Herbicide Environmental Risk Assessment
The following sections discuss the chemical description and product use; physical and chemical 

properties; environmental fate; and hazard identification for these herbicides. 

2.1 Chemical Description and Product Use

Triclopyr or triclopyr acid (C7-H 4-Cl3-NO3) (CAS No. 55335-06-3) is the common name for 

[(3,5,6-trichloro-2-pyridinly)oxy]acetic acid. There are no active commercial products for 

triclopyr acid. Triethylamine (TEA) salt and butoxyethyl ester (BEE) are two commercial forms 

of triclopyr. Garlon® 3A (EPA Reg. No. 62719-37) contains the active ingredient TEA (44.4%) 

and Pathfinder® II (EPA Reg. No. 62719-176) contains the active ingredient BEE (13.6%). 

Garlon® 3A also includes the chelating agent ethylene diamine tetraacetic acid and ethanol 

(USDA FS, 2011a). The other ingredients of Pathfinder® II were not specified by the 

manufacturing company. 

The proposed application methods for triclopyr are painting the undiluted triclopyr formulation 

on the surface of stumps or directly spraying stumps and /or sprouting foliage using a backpack 

sprayer with triclopyr mixed with imazapyr and metsulfuron-methyl. In spray applications, the 

herbicide sprayer or container is carried by backpack. The nozzle on the wand or gun jet of the 

backpack sprayer should not be positioned higher than the handlers' waist, reducing the 

likelihood that the chemical will come into direct contact with the arms, hands, or face of the 

worker. In addition, a large coarse droplet size applied as close to the target area as possible is 

used to minimize the potential for drift. 

Garlon® 3A is used at rates of 3/4 to 9 pound (lb) acid equivalent (a.e.) of triclopyr (1/4 to 3 

gallons of Garlon® 3A) per acre to control broadleaf weeds and woody plants (Dow 

AgroSciences, 2011a). Pathfinder® II is used at no more than 8 lb a.e. per acre per year on noncrop areas (Dow AgroSciences, 2011b). The Garlon® 3A and Pathfinder® II label requirements 

for the restricted-entry interval are 48 hours and 12 hours, respectively (Dow AgroSciences 

2011a; 2011b). During the restricted entry interval, entry is not allowed except for workers with 

the proper personal protective equipment (PPE).

Imazapyr (CAS No. 81334-34-1) is an imidazolinone herbicide while metsulfuron-methyl (CAS 

No. 74223-64-6) is a sulfonylurea herbicide. Both products are a common mix partners with 

triclopyr in the control of woody vegetation. Arsenal® (EPA Reg. No. 241-346) contains 27.8% 

or 28.7% isopropylamine salt of imazapyr and 72.2% or 71.3% other ingredients. The Escort®

XP formulation (EPA Reg. No. 352-439) contains 60% metsulfuron-methyl and 40% other 

ingredients. For low-volume foliar brush control, the Arsenal®application rate is 0.5 to 1% by 

volume and 2 oz per acre when in a tank mix with Escort® XP. Garlon® 3A may be added to the 

mix at 1 to 2 pints per acre (BASF, 2012a). The Arsenal® and Escort® XP label requirements for 

the restricted-entry interval are 48 hours and 4 hours, respectively (BASF, 2012a; DuPont, 

2012a). 

2.2 Physical and Chemical Properties 

Triclopyr is a colorless solid with a melting point of 148-150o

C. Triclopyr TEA is a grayish 

white granular solid with a melting point of 111-117oC (USEPA, 1998). Triclopyr acid, triclopyr 

TEA, and triclopyr BEE have vapor pressures of 1.26 x 10-6, <1 x 10-8, and 3.6 x 10-6 mm Hg, 
respectively, indicating that these compounds can volatilize into vapor and be transported as a

vapor or in aparticulate phase into the ambient air. Triclopyr acid and triclopyr TEA are soluble 

(water solubility of 430 mg/L and 4.12 x 105 mg/L, respectively) (HSDB, 2014a). Triclopyr 

BEE has relatively low solubility (6.8 mg/L) (USEPA, 1998). The basic physical and chemical 

properties of the commercial products, triclopyr TEA and triclopyr BEE are summarized in table 

2-1.

Table 2-1. Physical and chemical properties for triclopyr TEA and BEE. 

Sources: USEPA, 1998; HSDB, 2014a

Imazapyr is a clear, slightly viscous, pale yellow to dark green aqueous liquid, or white to tan

powder with a slight ammonia odor. Its melting point is 171o

C. Imazapyr has a low vapor 

pressure (1.79x10-11 mm Hg), and low Henry's Law constant (7.08x10-17 atm-cu m/mol), 

suggesting low volatility from soil and water. It is considered highly soluble (water 

solubility of 1.13x104 mg/L) (HSDB, 2014b). The basic physical and chemical properties of 

imazapyr are summarized in table 2-2.

Metsulfuron-methyl is a white or colorless crystal, or white to pale yellow solid with a faint, 

sweet, ester-like odor with a melting point of 163o

C. Metsulfuron-methyl has low vapor 

pressure (2.5x10-12 mm Hg), and low Henry's Law constant (1.32x10-16 atm-cu m/mol). It 

also has a high solublility in water (water solubility of 9.50x103 mg/L) (HSDB, 2014c). The 

basic physical and chemical properties of metsulfuron-methyl are summarized in table 2-2.

Parameters Triclopyr TEA Triclopyr BEE

CAS No. 57213-69-1 64700-56-7

Molecular Formula C13H19Cl3N2O3 C13H16Cl3NO4 

Molecular Structure

Molecular Weight 358.67 356.63

Melting Point (o

C) 111-117oC NA

Henry Law Constant 

(atm m3 mol-1) 1.15 x 10-14 2.47 x 10-7

Vapor Pressure 

(mm Hg) (25o

C) <1 x 10-8 3.6 x 10-6

Water Solubility, 

mg/L 412,000 7.4

Log Kow 1.5011 4.0133

Appendix E. Herbicide Environmental Risk Assessment
Table 2-2. Physical and chemical properties for imazapyr and metsulfuron-methyl.

Source: HSDB, 2014b, c

2.3 Environmental Fate

The environmental fate describes the processes by which triclopyr, imazapyr, and metsulfuronmethyl move and degrade in the environment. Environmental fate processes include: 1) 

mobility, persistence, and degradation in soil, 2) movement to air, 3) migration potential to 

groundwater and surface water, and 4) plant uptake. 

In soil, triclopyr is expected to have high mobility (Koc's ranging from 1.5 to 134 mL/g organic 

carbon (oc)). Under anaerobic conditions, triclopyr is persistent with a half-life of approximately

1,300 days. Under aerobic conditions, triclopyr biodegrades in silty clay loam and silty loam 

soils with half-lives of 8 and 18 days, respectively. The half-life of the major metabolite, 3,5,6-

trichloro-2-pyridinol (TCP), is 30 to 90 days (HSDB 2014a). In soil, both forms of triclopyr 

degrade into several intermediates before ultimately degrading to carbon dioxide (CO2) (NPIC,

2002). In air (ambient atmosphere), triclopyr is expected to exist in both the vapor and 

particulate phase based on its vapor pressure (1.26 x 10-6 mm Hg at 25 oC). Triclopyr in the 

vapor phase will degrade to hydroxyl radicals through a photochemical reaction with an 

estimated half-life of 3.3 days. Triclopyr undergoes photodecomposition with a half-life of <12 

hours. In water, triclopyr is mainly broken down by exposure to sunlight. The half-life of 

triclopyr in water ranges from 1 to 10 days depending on water conditions such as turbidity 

(NPIC, 2002). Triclopyr degrades slowly in a soil:water system incubated aerobically, with a 

reported half-life of 142 days (HSDB 2014a). The potential for bioconcentration in aquatic 

organisms is low with an estimated bioconcentration factor (BCF) of 3. Triclopyr’s half-life in 

plants ranges from 3 to 10 days, and the primary metabolite is 3,5,6-trichloro-2-methoxypyridine

(NPIC, 2002).

Parameters Imazapyr Metsulfuron-methyl

CAS No. 81334-34-1 74223-64-6

Molecular Formula C13H15N3O3 C14H15N5O6S

Molecular Structure

Molecular Weight 261.28 381.37

Melting Point (o

C) 171 163

Henry Law Constant (atm 

m3 mol-1) 7.08 x 10-17 1.32 x 10-16

Vapor Pressure 

(mm Hg) (25o

C) 9.0 x 10-11 2.5 x 10-12

Water Solubility, mg/L 1.13E+04 9.5E+03

Log Kow 0.22 2.2
In soil, imazapyr is expected to have high mobility (Koc’s ranging from 8.2 to 110 mL/g oc for 

soil) (USEPA, 2007). Imazapyr biodegrades with aerobic soil half-lives ranging from 17.7 to 

63.1 days. In ambient atmosphere, imazapyr will likely exist in the particulate phase based on its 

vapor pressure (an estimated vapor pressure of 9.0x10-11 mm Hg at 25o C). In water, the 

potential for bioconcentration in aquatic organisms is low due to an estimated BCF of 3.

Exposure to ultraviolet (UV) light in aqueous solutions results in complete degradation of

imazapyr in 48 hrs, with a half-life of 7 hrs (HSDB, 2014b).

In soil, metsulfuron-methyl is expected to have moderate to high mobility (Koc values ranging 

from 4 to 345 mL/g oc). Metsulfuron-methyl is more mobile in alkaline soils than in acidic soils. 

A typical half-life for metsulfuron-methyl in soil is 30 days (ranging from 14 to 180 days). Soil 

temperature, moisture content, and pH influence degradation of metsulfuron-methyl.

Metsulfuron-methyl degrades faster under high moisture content and high temperature and acidic 

conditions (Trevathan, 2002). In air, metsulfuron-methyl will exist solely in the particulate 

phase (vapor pressure of 2.50x10-12 Hg at 25o

C). Metsulfuron-methyl may undergo direct 

photolysis based on 50 and 76% degradation in an aqueous solution after a 15 and 36 hour

exposure to UV irradiation, respectively. In water, metsulfuron-methyl may undergo direct 

photolysis. It is not expected to adsorb to suspended solids and sediment based upon its Koc 

values. Metsulfuron-methyl has BCF values ranging from 1-17 suggesting the potential for

bioconcentration in aquatic organisms is low (HSDB, 2014b). 

2.4 Hazard Identification 

Technical triclopyr acid, TEA, and BEE are slightly toxic for the oral and dermal exposure 

routes (Toxicity Category III). They are practically non-toxic for the inhalation exposure route 

(Toxicity Category IV) and are not dermal irritants. However, triclopyr TEA was corrosive and 

BEE was minimally irritating in the primary eye irritation study. Triclopyr TEA and BEE are

dermal sensitizers. The primary target organs of triclopyr are the liver and kidney (USEPA,

1998; USEPA, 2002a). 

Imazapyr is practically non-toxic for oral (Toxicity Category IV) and dermal (Toxicity Category 

III) routes of exposure. For the acute inhalation route of exposure, imazapyr is classified in 

Toxicity Category II. It is not irritating to the skin, and is negative for dermal sensitization. 

However, imazapyr causes acute irreversible eye damage (Toxicity Category I) (USEPA, 2006).

Metsulfuron-methyl is non-toxic for oral, dermal, and inhalation exposure routes (Toxicity 

Category IV). It is not a skin irritant or sensitizer, but is a slight eye irritant (USEPA, 2002b). 

2.4.1 Mechanism of Action and Pharmacokinetics 

Triclopyr, a weak acid, is excreted primarily from the kidney through an active transport 

process (Timchalk and Nolan, 1997; Timchalk et al., 1990; 1997). At very high doses, it 

may interfere with the excretion of other weak acids. However, concentrations of weak acids 

in the body under normal environmental exposures will be far below levels that would

interfere in the active transport process. Therefore, this mechanism of active transport is not 

Appendix E. Herbicide Environmental Risk Assessment
expected to play a substantial role in potential health effects. Imazapyr is a plant amino acid 

synthesis inhibitor, which inhibits acetolactate synthase (ALS), an enzyme found only in 

plants and microorganisms. Plants require ALS for the synthesis of essential branched chain 

amino acids for their growth. Animals lack ALS and do not synthesize these amino acids by 

themselves (USDA FS, 2011b). A mechanism of action for imazapyr in mammals is 

currently unknown (USEPA, 2005a; HSDB, 2014b). Metsulfuron-methyl is also a plant 

amino acid synthesis inhibitor with the same mechanism of action as imazapyr. The 

mechanism of action of metsulfuron-methyl in mammals is not clear (USDA FS, 2005). 

Pharmacokinetic studies show that triclopyr is absorbed and excreted almost exclusively in 

the urine through acid hydrolysis (Shackelford et al., 1999). Following oral exposure, 

triclopyr is absorbed and excreted relatively rapidly, with half-lives for oral absorption and 

urinary excretion of 3.61 and 1.1 hours, respectively. A majority of ingested triclopyr is 

excreted unchanged in the urine, although minor metabolites can be formed (USFS, 2011a). 

Triclopyr has very low potential to be absorbed through the skin or to accumulate in humans

at acutely toxic levels because it is absorbed slowly through the skin and is rapidly 

eliminated (HSDB, 2014a). Imazapyr and metsulfuron-methyl are absorbed and excreted 

through urine and feces mostly unchanged (HSDB 2014b,c). In a rat study, 87% of an orally 

administered imazapyr dose was excreted in the urine and feces within 24 hours (HSDB, 

2014b). Metsulfuron-methyl is eliminated from rats quickly (9-16 hours at low doses, and 

23-29 hours for high doses) (HSDB, 2014c).

2.4.2 Acute Toxicity

The acute oral rat LD50 values for TEA, Garlon® 3A, BEE and Pathfinder® II formulations 

show low toxicity (Category III) (table 2-3). Acute toxicity values for BEE are lower 

compared to those for TEA and Garlon® 3A, but are still within the same toxicity category.

The TEA, BEE and Pathfinder® II formulations have low dermal toxicity (Category III) and 

Garlon® 3A has very low (Category IV) acute dermal toxicity. The acute inhalation 

toxicities for TEA, Garlon® 3A, BEE and Pathfinder® II formulations are all very low 

(Category IV). None of the formulations are dermal irritants. Triclopyr TEA, Garlon® 3A, 

and BEE are dermal sensitizers. However, Pathfinder® II is not a dermal sensitizer. The 

primary eye irritation study results between the technical active ingredients and the proposed 

formulations vary from corrosive (triclopyr TEA - Category I), to may cause severe irritation 

with corneal injury (Garlon® 3A), and from minimally irritating (BEE) to slight temporary 

eye irritation (Pathfinder® II).
Table 2-3. Comparative acute mammal toxicity between triclopyr technical active ingredients 

and proposed formulations.

Sources: USEPA, 1998; Dow AgroSciences, 2010; 2011c

Acute mammal toxicity data for imazapyr and Arsenal® show very low toxicity for oral, 

dermal, and inhalation routes (table 2-4). The formulation is much less toxic causing no eye 

irritation while the technical imazapyr can cause irreversible eye damage. 

Table 2-4. Comparative acute mammal toxicity between imazapyr technical active ingredient 

and the proposed formulation.

Sources: USEPA, 2005a; BASF, 2012b

Toxicity Study TEA

(44.4% a.i.)

Garlon® 3A BEE

(97.1% a.i.)

Pathfinder® II

Acute Oral LD50

(rat)

1,847 mg/kg 

(M&F) (III)

1,847 mg/kg (III) 803 mg/kg (M&F) 

(III)

1,000 mg/kg (F) 

(III)

Acute Dermal 

LD50 (rat for 

technical and 

rabbit for Garlon®

3A)

>2,000 mg/kg 

(III)

>5,000 mg/kg (IV) >2,000 mg/kg (III) >2,000 mg/kg (III)

Acute Inhalation 

LC50 (rat)

>2.6 mg/L 

(IV)

>2.6 mg/L (IV) >4.8 mg/L (IV) >5.0 mg/L (IV)

Primary Eye 

Irritation (rabbit)

Corrosive (I) May cause severe 

irritation with 

corneal injury

Minimally irritating 

(III)

Slightly temporary 

irritation

Primary Skin 

Irritation

Not irritating 

(IV)

Brief contact- not 

irritating; prolonged 

contact may cause 

slight skin irritation 

with local redness; 

repeated contact may 

cause skin burns

Not irritating (IV) Prolonged skin 

contact may cause 

moderate skin 

irritation with local 

redness

Dermal 

Sensitization 

(Guinea pig)

Sensitizer Sensitizer Sensitizer Non-sensitizer

 

Toxicity Study Imazapyr Technical Arsenal®

Acute Oral LD50 (rat) >5,000 mg/kg (IV) >5,000 mg/kg (IV)

Acute Dermal LD50 (rat) >2,000 mg/kg (III) >2,000 mg/kg (III)

Acute Inhalation LC50 (rat) 1.3 mg/L(gravimetric)

5.1 mg/L (nominal) (III)

>5.3 mg/L (IV)

Primary Eye Irritation (rabbit) Irreversible Eye Damage (I) Non-irritating (IV)

Primary Skin Irritation Non-irritating to slight erythema and 

edema (IV)

Mildly-irritating (IV)

Dermal Sensitization (Guinea pig) Negative Negative

Appendix E. Herbicide Environmental Risk Assessment
Acute mammal toxicity for technical metsulfuron-methyl and Escort® XP show low to very 

low toxicity for oral, dermal, and inhalation routes (table 2-5). The formulation is less toxic 

for the dermal route and causes less eye and skin irritation. 

Table 2-5. Comparative acute mammal toxicity between metsulfuron-methyl technical active 

ingredient and proposed formulation.

Sources: US FS, 2005; DuPont, 2012b

2.4.3 Sub-Chronic/Chronic Toxicity

Based on chronic and subchronic toxicity studies, the kidney appears to be the most sensitive 

target organ for triclopyr. Decreased phenolsulfonphthalein urinary excretion and reduced 

absolute and relative kidney weights in dogs were observed after exposure to a dose of 2.5 

mg/kg/day for 183/184 (male/female) days (USDA FS, 2011a). Kidney effects on

hematological and histopathological changes and increased kidney weight in rodents were 

observed after subchronic exposure to triclopyr doses at 70 mg/kg/day for 90 days. Damage 

ZDVFKDUDFWHUL]HGDVGHJHQHUDWLRQRIWKHSUR[LPDOWXEXOHVRIWKHNLGQH\VPJNJGD\IRU

90 days) and increases in kidney weight (USDA FS, 2011a). The No Observed Adverse 

Effect Level (NOAEL) for kidney toxicity in rats is 5 mg/kg bw/day from a two generation 

dietary reproduction study in rats. This is the basis of the chronic reference dose (RfD) for 

triclopyr (USEPA, 2002a). Other general systemic effects of triclopyr include signs of liver 

damage and a decrease in food consumption, growth rate, and gross body weight occurring at 

high doses (USDA FS, 2011a).

Subchronic and chronic studies using imazapyr have been conducted in rats, rabbits, and 

dogs. The 90-day oral toxicity study in rats shows that the dermal and systemic NOAEL was 

1,695 mg/kg/day for males and 1,784 mg/kg/day for females at the highest dose tested

(HDT). The 21/28-day dermal toxicity study in rabbits showed that the dermal and systemic 

NOAEL was 400 mg/kg/day (HDT). The chronic toxicity study in dogs (1 year) showed that 

the NOAEL was 250 mg/kg/day (HDT). The NOAEL of 250 mg/kg/day was selected as the 

basis of the chronic RfD for imazapyr because it was the lowest NOAEL. The dose of 250 

mg/kg/day was the highest dose tested in the dog study and no adverse effects were observed. 

USEPA used this dose for calculating the chronic RfD based on a structural analog of 

imazapic to choose a toxic endpoint. Imazapic causes skeletal muscle effects in dogs at 137 

mg/kg/day (male) and 180 mg/kg/day (female) (USEPA, 2006). 

Subchronic and chronic studies with metsulfuron-methyl have been conducted using rats, 

rabbits, and dogs. The 90-day oral toxicity study in rats reported a NOAEL of 68 mg/kg/day 

(male) and 64 mg/kg/day (female) with a Lowest Observable Adverse Effect Level (LOAEL) 

Toxicity Study Metsulfuron-methyl Technical Escort® XP

Acute Oral LD50 (rat) >5,000 mg/kg (IV) >5,000 mg/kg

Acute Dermal LD50 (rat) 3,000 mg/kg (III) >5,000 mg/kg

Acute Inhalation LC50 (rat) >2 mg/L (IV) >5 mg/L

Primary Eye Irritation (rabbit) Irritation reversible in 7 days Slight irritation

Primary Skin Irritation Moderate irritation in 72 hours No irritation

Dermal Sensitization (Guinea pig) Negative Negative
of 521 mg/kg/day (male) and 659 mg/kg/day (female) based on a transient decrease in body 

weight. The 21-day dermal toxicity study in rabbits showed that the dermal NOAEL was 

125 mg/kg/day with a LOAEL of 500 mg/kg/day based on skin lesions (diffuse/multifocal 

dermatitis). The systemic NOAEL was 125 mg/kg/day with a LOAEL of 500 mg/kg/day 

based on an increased incidence of diarrhea. The chronic toxicity study in male and female 

rats showed that the NOAEL was 25 mg/kg/day with a LOAEL of 250 mg/kg/day based on

body weight loss. The NOAEL of 25 mg/kg/day was selected as the basis for the chronic 

RfD for metsulfuron-methyl because it was the lowest NOAEL observed in the toxicity 

studies (USEPA, 2002b).

2.4.4 Carcinogenicity/Mutagenicity 

Based on the USEPA/OPP chemical evaluation of carcinogen potential (USEPA, 2013), 

triclopyr is “Not Classifiable as to Human Carcinogenicity (Group D)”. Triclopyr was 

classified as a Group D chemical because the evidence of the increase in mammary tumors in 

the female rat and mouse, and adrenal pheochromocytomas in the male rat are marginal. 

There was no additional support from structural analogs or genotoxicity studies (USEPA,

1998). Triclopyr is not considered mutagenic or genotoxic based on a lack of evidence from 

several in vitro and in vivo studies (USEPA, 2002a). However, two unpublished studies on 

triclopyr ingestion by rats and mice have suggested increased frequency of mammary gland 

cancer at high doses. Mutagenicity studies using triclopyr (triclopyr technical acid, triclopyr 

BEE, and non specified triclopyr) in mice and rat did not show mutagenicity (USDA FS, 

2011a).

USEPA (2013a) classifies imazapyr as “Evidence of Noncarcinogenicity for Humans (Group 

E)” based on a study in mice that showed no evidence of carcinogenicity. In the 

carcinogencity study, the NOAEL was 10,000 ppm (1,301 mg/kg/day in males and 1,639 

mg/kg/day in females). The level was the HDT and there was no LOAEL (USEPA, 2005a). 

Imazapyr is not considered mutagenic or genotoxic based on a lack of evidence from several 

in vitro and in vivo studies (USEPA, 2005a). The results for the Ames assay was negative up 

WRȝJSODWH The results of in vitro mammalian cell gene mutation and chromosome 

aberration studies were negative up to subchronic WR[LFGRVHVȝJPOZLWKDQGZLWKRXW

activation. 

USEPA (2013a) classifies metsulfuron-methyl as “Not Likely to Be Carcinogenic to 

Humans” based on studies in rats that show no evidence of carcinogenicity. In one 

carcinogenicity study, the NOAEL was 25 mg/kg/day for both male and female rats. The 

LOAEL was 250 mg/kg/day for both male and female rats based on reduced body weight. In 

another carcinogenicity study, the NOAEL was 666 mg/kg/day (male) and 836 mg/kg/day 

(female) (USEPA, 2002b). Metsulfuron-methyl is not considered mutagenic or genotoxic 

based on a lack of evidence from several in vitro and in vivo studies (USEPA, 2002b). 

2.4.5 Development and Reproductive Effects

The current chronic RfD for triclopyr was based on a two-generation reproduction study 

(USEPA, 1998). In this study, male and female rats were exposed to dietary concentrations 

of triclopyr resulting in doses of 0, 5, 25, or 250 mg/kg/day, except that the parent males in 

Appendix E. Herbicide Environmental Risk Assessment
the high dose group were exposed to a concentration resulting in a daily dose of 100 mg/kg 

bw/day. The 5 mg/kg/day dose groups showed no evidence of adverse effects in the parents 

or offspring. At 25 mg/kg/day, degeneration of renal proximal tubules was observed only in 

adult animals. At 250 mg/kg/day, parental effects included decreased food consumption and 

body weights as well as histopathological changes in the liver and kidney. Fetotoxic effects, 

including decreased pup survival and litter sizes, were noted at 250 mg/kg/day. The NOAEL 

of 25 mg/kg/day for reproductive effects from this study is supported by a three-generation 

reproduction study using the same strain of rats with no adverse effects observed to offspring 

at doses of 3, 10, or 30 mg/kg/day (Hanley et al., 1984); and by an earlier study summarized 

by the Forest Service in which no adverse reproductive effects were observed in rats exposed 

to doses up to 30 mg/kg bw/day (USDA FS, 2011a).

The developmental studies on triclopyr acid, triclopyr TEA, and triclopyr BEE show that 

triclopyr can cause adverse developmental effects including birth defects at sufficiently high 

doses. The developmental studies for the triclopyr salt and ester in rats show that the 

maternal NOAEL was 100 mg/kg/day, with a LOAEL of 300 mg/kg/day based on mortality

(triclopyr salt and ester), clinical signs, necropsy findings, decreased body weight gains, 

decreased food consumption, increased water consumption, and increased relative kidney and 

liver weight (triclopyr ester). The developmental NOAEL was 100 mg/kg/day with a 

LOAEL of 300 mg/kg/day based on decreased fetal weight, increased fetal and litter 

incidence of skeletal anomalies, increased fetal incidence of unossified sternebrae (triclopyr 

salt), increased incidence of hydrocephalus, cleft palate, microphthalmia/anophthalmia, 

retinal folds, thin diaphragm/protrusion of the liver, decreased fetal weight, and visceral and 

skeletal amomalies and variants (triclopyr ester). The maternal and developmental NOAELs 

and LOAELs in rabbits were 30 mg/kg/day and 100 mg/kg/day, respectively (USEPA, 

2002a). A consistent pattern with triclopyr, however, is that adverse developmental effects 

occur only at doses that are maternally toxic. The developmental studies conducted in rats 

and rabbits do not suggest substantial or consistent differences in the developmental effects 

of the various forms of triclopyr (USDA FS, 2011a).

The developmental studies in rats on imazapyr show that the maternal NOAEL was 300 

mg/kg bw/day with a LOAEL based on salivation at 1,000 mg/kg bw/day. The 

developmental NOAEL was 1,000 mg/kg/day (HDT) and no LOAEL was reported. The 

developmental studies in rabbit showed that the maternal NOAEL was 400 mg/kg bw/day 

(HDT) and the developmental NOAEL was 400 mg/kg bw/day (HDT). The reproduction 

studies in rats showed that the NOAEL for parental systemic, reproductive andoffspring was 

10,000 ppm (738 mg/kg bw/day in males and 933.3 mg/kg bw/day in females) (HDT)

(USEPA, 2005a).

The developmental studies in rodents on metsulfuron-methyl show that the maternal NOAEL 

and LOAEL were 250 mg/kg/day, and 1,000 mg/kg/day, respectively, with effects on 

salivation and decreased body weight gain-compensatory increase after dosing stopped. The 

developmental NOAEL and LOAEL were <1,000 mg/kg/day (HDT) and >1,000 mg/kg/day 

(HDT), respectively. The developmental studies in nonrodents show that the maternal 

NOAEL and LOAEL were 25 mg/kg/day, and 1,000 mg/kg/day, respectively, with effects on

increased mortality, decreased body weight gains, and clinical signs of anorexia, red/orange 
urine and/or exudate. The developmental NOAELwas 700 mg/kg/day (HDT). Reproduction 

studies in rats showed that the NOAEL for parental systemic was 34 mg/kg/day and 43 

mg/kg/day (male and female respectively). The LOAEL was 342 and 475 mg/kg/day (male 

and female respectively) based on decreased premating body weight gains. The reproductive 

NOAEL was 342 and 475 mg/kg/day (male and female respectively) (HDT). The offspring 

NOAEL was 342 and 475 mg/kg/day (male and female respectively) (HDT) (USEPA, 

2002b). 

2.4.6 Endocrine Effects

A literature search did not identify any study indicating the potential for triclopyr, imazapyr, 

and metsulfuron-methyl to disrupt endocrine function. None of these herbercides are among 

the group of pesticide active ingredients to be screened under the USEPA Endocrine 

Disruptor Screening Program. However, the identity of chemicals for screening is based on 

exposure potential, not on whether the pesticide is a known or likely potential endocrine 

disruptor (USEPA, 2014b). Fetal toxicity and abnormalities have been observed at higher 

doses using triclopyr, however, there is no indication that the effects occurred through a 

mechanism involving endocrine disruption (USDA FS, 2011a).

2.4.7 Potential Additive, Antagonistic, or Synergistic Effects:

A literature search was performed to identify any studies indicating additive (toxicity of the 

mixture is equivalent to the sum of the toxicities of the individual compounds), antagonistic

(toxicity of the mixture is less than additive), or synergistic (toxicity of the mixture is greater

than additive) effects from the mixing of the three herbicides. The search results indicate that 

the most common type of effect is additive toxicity and there may be mildly synergistic 

effects associated with the proposed herbicide mixture (Tatum, 2004). The formulations of 

the three herbicides proposed to be used in the ALB program have very low toxicity and any 

additive toxicity is anticipated to be low. 

3.0. DOSE-RESPONSE ASSESSMENT

3.1 Human Health Dose-Response Assessment

A dose-response assessment evaluates the dose levels (toxicity criteria) for potential human 

health effects including acute and chronic toxicity. The toxicity criteria sources include 

documents and on-line sources from the USEPA/OPP, USEPA Integrated Risk Information 

System, and the Agency for Toxic Substances and Disease Registry. If a criterion was not 

available from these sources, information in other regulatory documents or the primary literature 

was used. When toxicity criteria were developed, uncertainty factors (UFs) were incorporated to 

address data gaps, effects to sensitive groups, and variability in the study and/or human 

populations. 

As discussed in Section 2.4, triclopyr, imazapyr, and metsulfuron-methyl are not classified as 

human carcinogens. The noncancer toxicity criterion is developed by identifying a NOAEL, or 

LOAEL if an appropriate NOAEL is not available, and applying one or more uncertainty factors. 

Appendix E. Herbicide Environmental Risk Assessment
These values are used to calculate a RfD which is a dose that will not result in any adverse 

effects to an individual. 

3.1.1 Triclopyr

The acute and chronic RfDs for triclopyr (1 and 0.05 mg/kg bw/day, respectively) are derived 

from NOAEL values from the rat studies with an uncertainty factor of 100 added for interand intraspecies differences (USEPA, 2002a; USDA FS, 2011a). The acute RfD is based on 

a developmental study with triclopyr BEE in which no effects were noted at 100 mg/kg 

bw/day but maternal toxicity was noted at 300 mg/kg bw/day. The chronic RfD is based on a 

two- generation reproduction study in rats with triclopyr acid where no adverse effects were 

noted at 5 mg/kg bw/day but effects on the kidney (degeneration of renal proximal tubules) 

were noted at 25 mg/kg bw/day. Because of concerns for the reproductive and 

developmental toxicity of triclopyr, the chronic RfD is used to assess the risks to women of 

childbearing age associated with both acute and long-term exposure. USEPA (2002a)

indicates that the acute RfD is not applicable to females between the ages of 13-50 years—

i.e., of child bearing age. The basis for this recommendation appears to be signs of maternal 

toxicity observed at 30 mg/kg bw/day with a reported NOAEL of 5 mg/kg bw/day. As 

discussed below, the chronic RfD for triclopyr is 0.05 mg/kg bw/day, based on a NOAEL of 

5 mg/kg bw/day. Thus, for women of childbearing age, the EPA recommends an acute RfD 

of 0.05 mg/kg/day, which is equivalent to the chronic RfD.

3.1.2 TCP

TCP is a metabolite of triclopyr. The acute and chronic RfDs for TCP (0.025 and 0.012 

mg/kg bw/day, respectively) are based on NOAEL values from the rabbit and dog studies

(USEPA, 2002a, USDA FS, 2011a). The acute RfD is based on a developmental study in 

rabbits in which birth defects (an increased incidence of hydrocephaly and dilated ventricles) 

were noted at a dose of 100 mg/kg bw/day but no adverse effects were observed at 25 mg/kg 

bw/day. The chronic RfD is based on a chronic study in dogs in which changes in clinical 

chemistry were observed at the 48 mg/kg/day (LOAEL) and no effects were observed at the 

12 mg/kg/day dose (NOAEL).

For both acute and chronic exposures the uncertainty factor for TCP is set at 1000: 10 to 

account for uncertainties in species-to-species extrapolation and another factor of 10 to 

encompass sensitive individuals in the population, as well as an additional factor of 10 for the 

potential for increased sensitivity in children.

3.1.3 Imazapyr

The USEPA developed a chronic RfD of 2.5 mg/kg/day for imazapyr based on a 2-year dog 

study and a reported NOEL of 25 mg/kg/day that was adjusted using an uncertainty factor of 

100 for inter- and intraspecies differences (USEPA, 2006). USEPA did not develop an 

acute/single dose RfD for imazapyr. A developmental study in rats with imazapyr reported a 

maternal NOAEL of 300 mg/kg bw/day with a LOAEL based on salivation at 1,000 mg/kg 

bw/day (see Development and Reproductive Effects under Section 2.4). Based on the 
maternal NOAEL of 300 mg/kg bw/day applying by an uncertainty factor of 100, an acute 

RfD will be 3 mg/kg/day, which is similar to the chronic RfD for imazapyr.

3.1.4 Metsulfuron-Methyl

The USEPA developed a chronic RfD of 0.25 mg/kg/day for metsulfuron-methyl based on a 

2- year rat study and a reported NOEL of 25 mg/kg/day adjusted using an uncertainty factor 

of 100 for inter- and intraspecies differences (USEPA, 2002b). USEPA did not develop an 

acute/single dose RfD for metsulfuron-methyl. A reproduction study in rats reported a 

parental systemic NOAEL of 34 mg/kg/day, with a LOAEL of 342 mg/kg/day based on 

decreased body weight (see Development and Reproductive Effects under Section 

2.4). Based on the NOAEL of 34 mg/kg bw/day and an uncertainty factor of 100, an acute 

RfD will be 0.34 mg/kg/day, which is similar to the chronic RfD for metsulfuron-methyl.

3.1.5 Drinking Water

Triclopyr, imazapyr, and metsulfuron-methyl are not currently regulated under the Safe 

Drinking Water Act. Maximum Contaminant Levels protective of human health are not 

established for these compunds. 

3.2 Ecological Effects Analysis

This section of the risk assessment discusses available ecological effects data for terrestrial and 

aquatic biota. Available acute and chronic toxicity data are summarized for all major taxa and 

will be integrated with the exposure analysis section to characterize the risk of triclopyr, 

imazapyr, and metsulfuron-methyl to nontarget wildlife and domestic animals. Information in 

this section was gathered from on-line databases and searches for relevant peer reviewed and 

non-peer reviewed literature. Recent reviews of triclopyr, imazapyr, and metsulfuron-methyl by 

the Forest Service were used to summarize available ecotoxicological effects data.

3.2.1 Aquatic Effects Analysis

3.2.1.1 Fish and Amphibians

Triclopyr and TCP

The acute fish toxicity studies show that triclopyr and TCP acute toxicities to fish range 

from practically non-toxic to highly toxic (USEPA Ecotoxicity Categories, USEPA, 

2014c) (table 3-1). The acute median effective concentrations (96-hour EC50) for

triclopyr TEA, triclopyr acid, TCP, and triclopyr BEE from the fish toxicity studies are 

131 mg a.e./L, 15.3 mg a.e./L, 3.19 mg a.e./L, and 0.539 mg a.e./L, respectively (USDA 

FS, 2011a). Based on the acute toxicity data, triclopyr TEA is much less toxic to fish 

than triclopyr acid, triclopyr BEE, or TCP. Compared to triclopyr BEE, triclopyr TEA is 

less acutely toxic by a factor of approximately 240, and TCP is less acutely toxic by a 

factor of approximately 6.

Appendix E. Herbicide Environmental Risk Assessment
Table 3-1. Acute fish toxicity data for triclopyr acid, TEA, BEE, and TCP.

Test Organism Endpoint/Length Toxicity 

Value (mg/L)

NOEC 

(mg/L)

Triclopyr Acid

Bluegill sunfish 96-hour LC 50 155.4 NR

Rainbow trout 96-hour LC50 79.2 NR

Chinook salmon 96-hour LC50 9.7 NR

Coho salmon 96-hour LC50 9.6 NR

Chum salmon 96-hour LC50 7.5 NR

Sockeye salmon 96-hour LC50 7.5 NR

Rainbow trout 96-hour LC50 7.5 NR

Pink salmon 96-hour LC50 6.3 NR

Median 15.3

Triclopyr TEA

Tidewater silverside 96-hour LC50 40.1 NR

Bluegill sunfish 96-hour LC50 65.1 NR

Catfish, juv 96-hour LC50 78.3 NR

Fathead minnow 96-hour LC50 85.8 NR

Fathead minnow 96-hour LC50 86.4 NR

Chum salmon 96-hour LC50 96.1 NR

Chinook salmon 96-hour LC50 99 NR

Sockeye salmon 96-hour LC50 112 NR

Coho salmon, juv 96-hour LC50 127.2 NR

Catfish, adult 96-hour LC50 141 103

Rainbow trout 96-hour LC50 151 NR

Coho salmon 96-hour LC50 167 NR

Fathead minnow 96-hour LC50 168.5 NR

Bluegill sunfish 96-hour LC50 233.1 NR

Rainbow trout 96-hour LC50 273.7 NR

Rainbow trout 96-hour LC50 286 NR

Fathead minnow 96-hour LC50 422.8 NR

Median 130.7

Triclopyr BEE

Bluegill sunfish 96-hour LC50 0.25 0.091

Coho salmon 96-hour LC50 0.26 NR

Coho salmon 96-hour LC50 0.47 NR

Fathead minnow 96-hour LC50 0.5 NR

Bluegill sunfish 96-hour LC50 0.54 NR

Bluegill sunfish 96-hour LC50 0.58 NR

Coho salmon 96-hour LC50 1 NR

Fathead minnow 96-hour LC50 1.5 0.97

Median 0.54

TCP

Rainbow trout 96-hour LC50 1.5 NR

Coho salmon 96-hour LC50 1.8 NR

Chum salmon 96-hour LC50 1.8 NR

Chinook salmon 96-hour LC50 2.1 NR

Sockeye salmon 96-hour LC50 2.5 NR
Test Organism Endpoint/Length Toxicity 

Value (mg/L)

NOEC 

(mg/L)

Pink salmon 96-hour LC50 2.7 NR

Bluegill sunfish 96-hour LC50 12.5 NR

Rainbow trout 96-hour LC50 12.6 NR

Median 3.19

NR = not reported Source: USDA FS, 2011a, Table 33

The sublethal effects of Garlon® 4 were investigated on rainbow trout using flow-through 

systems (Johansen and Green, 1990). Fish were lethargic at concentrations of 0.32-0.43

mg/L. Another study reported behavioral changes in rainbow trout for Garlon® 4 at 0.6

mg/L and Garlon® 3A at 200 mg/L (Morgan et al., 1991).

Chronic fish toxicity studies were conducted using triclopyr TEA, triclopyr BEE, and 

TCP and are summarized in USDA FS (2011a). The 28-day toxicity study for triclopyr 

TEA in fathead minnow reported a NOEC of 32.4 mg a.e./L and a LOEC of 50.2 mg 

a.e./L based on effects to length. The chronic toxicity study for triclopyr BEE in rainbow 

trout reports a NOEC of 0.019 mg a.e./L and a LOEC of 0.034 mg a.e./L based on effects 

to larval weight and length (USEPA, 2009). The chronic toxicity study for TCP in 

rainbow trout reports a NOEC of 0.178 mg/L and a LOEC of 0.278 mg/L based on 

effects to length and weight (USDA FS, 2011a). The chronic fish effects data show that 

triclopyr BEE is the most toxic form of triclopyr and that TCP is more toxic than 

triclopyr TEA. 

Acute toxicity data for aquatic phase amphibians is limited. An acute toxicity study 

using the African clawed frog, Xenopus laevis, exposed to Garlon® 3A shows that 

triclopyr TEA is slightly toxic with a 96-hour LC50 of 84 mg a.e./L (USDA FS, 2011a). 

This LC50 is well within the range of LC50 YDOXHV§WRPJDH/IRUWULFORS\U

TEA in fish. The acute toxicity studies in embryos and tadpoles exposed to triclopyr 

BEE formulations show triclopyr BEE is slightly toxic to amphibian embryos with a

median 96-hour LC50 of 17.78 mg a.e./L, and moderately toxic to tadpoles with a median 

96-hour LC50 of 2.34 mg a.e./L. The acute toxicity of triclopyr BEE to tadpoles varies 

from species to species (Rana pipiens is the most sensitive species and R. clamitans is the 

least sensitive species). Tadpoles are more sensitive than embryos by approximately an 

order of magnitude. This difference in sensitivity may reflect the rapid uptake of 

triclopyr BEE through the gills of tadpoles, relative to passive uptake by amphibian 

embryos (USDA FS, 2011a). The acute toxicity data indicate that amphibians are less 

sensitive to triclopyr BEE than fish. The acute toxicity data in amphibians for triclopyr 

BEE all involve triclopyr formulations. No data appears to be available regarding the 

toxicity of unformulated triclopyr BEE or TCP to amphibians. The acute amphibian 

toxicity data for triclopyr TEA and BEE formulations are summarized in table 3-2.

Appendix E. Herbicide Environmental Risk Assessment
Table 3-2. Acute amphibian toxicity data for triclopyr TEA and BEE formulations

Test Organism Endpoint/Length Toxicity Value

(mg a.e./L)

NOEC 

(mg a.e./L)

Triclopyr TEA

African clawed frog, Xenopus laevis 96-hour LC50 84 NR

Triclopyr BEE Formulations (Embryos)

Xenopus laevis 96-hour LC50 13.7 NR

Xenopus laevis 96-hour LC50 15.0 NR

Bufo americanus 96-hour LC50 15.1 NR

Rana pipiens 96-hour LC50 23.3 NR

Rana clamitans 96-hour LC50 24.6 NR

Median 17.78

Triclopyr BEE Formulations (Tadpoles)

Rana pipiens 96-hour LC50 0.79 NR

Bufo americanus 96-hour LC50 0.88 NR

Xenopus laevis 96-hour LC50 1.70 NR

Rana pipiens 96-hour LC50 2.79 NR

Rana clamitans 96-hour LC50 3.01 NR

Rana pipiens 96-hour LC50 3.39 NR

Rana clamitans 96-hour LC50 11.50 NR

Median 2.34

NR = Not reported Source: USDA FS, 2011a

In addition to standardized acute toxicity studies there have been frog embryo 

teratogenesis studies conducted using Garlon® 3A and Garlon® 4 (Perkins et al., 2000). 

In the assay, X. laevis embryos were exposed to the test solution in Petri dishes for 96 

hours and observed for malformations. No hind limb abnormalities were reported. The 

abnormalities observed in the study include uncoiling of the gut, edema, blistering, 

abnormal pigmentation, and axial twisting in control embryos. However, there were no

statistically significant increases in abnormalities in any groups exposed to Garlon® 3A or 

Garlon® 4 at sublethal levels. The study results indicate that triclopyr at sublethal 

concentrations is not likely to cause reproductive or teratogenic effects in amphibians.

Imazapyr

The acute toxicity of imazapyr is classified as practically non-toxic to fish based on LC50

values of >100 mg a.e./L for imazapyr acid (USDA FS, 2011b). The acute toxicity for

the isopropylamine salt of imazapyr is also practically non-toxic to fish based on acute 

bioassays in bluegill and trout. The acute toxicity for Arsenal® herbicide (27.8% a.i 

isopropylamine salt of imazapyr and 72.2% inert) is slightly toxic with a 96-hour LC50 of 

41 mg a.e./L in bluegill and 21 mg a.e./L in trout. The acute fish toxicity data for 

imazapyr are summarized in table 3-3.
Table 3-3. Acute and chronic fish toxicity data for imazapyr.

Test Organism Endpoint/Length Toxicity Value

(mg a.e./L)

NOEC 

(mg a.e./L)

Imazapyr Acid

Bluegill sunfish 96-hour LC50 >100 NR

Atlantic silversides 96-hour LC50 NR >184

Bluegill sunfish 96-hour LC50 >100 NR

Rainbow trout 96-hour LC50 >100 NR

Channel catfish 96-hour LC50 >184 NR

Fathead minnow Early life-stage (egg-tofry) NR 120

Fathead minnow Full Life Cycle NR 118

Rainbow trout Early life-stage (egg-tofry)NR 43.1

(LOEC: 92.4)

Imazapyr Isopropylamine (IPA) Salt

Bluegill sunfish 96-hour LC50 >815.5 NR

Rainbow trout 96-hour LC50 >110 110

Arsenal® Herbicide 

Bluegill sunfish 96-hour LC50 40.68 NR

Rainbow trout 96-hour LC50 20.8 10.4

NR = Not reported Source: USDA FS, 2011b

A micronucleus assay using Tilapia rendalli (an herbivorous fish native to Africa) 

indicated positive mutagenic activity (USDA FS, 2011b; Grisolia, 2002). In this 

screening test, fish were exposed to imazapyr at 20, 40, or 80 mg/kg through intraabdominal injections. A statistically significant increase in erythrocyte micronuclei was 

observed in the 80 mg/kg dose groups. However, the finding of this study does not have 

a substantial impact on the hazard identification for fish because the exposure route was 

atypical, and a positive response was only seen at the maximum dose of 80 mg/kg. In 

addition, imazapyr does not appear to be mutagenic or carcinogenic in mammals as 

discussed in the human health section of this risk assessment.

The USEPA/OPP risk assessment for the California red-legged frog summarized two fish 

kill incidents associated with imazapyr (USEPA, 2007). The first incident reported a 63 

fish and algae kill in a pond 60 feet away from a mixed herbicidal spray. A mixture of 

the isopropylamine salt of imazapyr, diuron and metsulfuron-methyl was sprayed onto a 

fence row and may have entered the pond from drift and/or runoff. However, it cannot be 

definitively determined that the fish kill was due to exposure to imazapyr. The second 

incident involved a goldfish kill. The cause of the kill could not be determined, but there 

was suspected runoff and drift into the pond after an aerial application of an imazapyr 

formulation to a nearby 145 acres. 

The long-term toxicity of imazapyr acid to fathead minnows has been tested in an early 

life-stage (egg to fry) study and a full life cycle study (USDA FS, 2011b). Neither study 

detected adverse effects at concentrations of up to about 120 mg a.e./L. The early lifeAppendix E. Herbicide Environmental Risk Assessment
stage chronic toxicity study in rainbow trout for imazapyr acid reported a NOEC of 43.1 

mg a.e./L and a LOEC of 92.4 mg a.e./L due to reduced hatch and fry survival. Both 

acute and chronic toxicity studies in fish indicate that trout appear to be the most 

sensitive species. 

No long-term toxicity studies on imazapyr formulations have been conducted. The acute 

NOAEC of 110 mg a.e./L for the isopropylamine salt of imazapyr in rainbow trout is 

above the longer-term NOAEC of 43.1 mg a.e./L for the imazapyr acid. However, the 

acute NOAEC of 10.4 mg a.e./L for the Arsenal® herbicide formulation in rainbow trout 

is below the longer-term NOAEC for the imazapyr acid. 

No information is available regarding the toxicity of imazapyr to aquatic-phase 

amphibians. Following a standard USEPA approach, fish toxicity data is used for aquatic 

phase amphibians assuming that fish are approximately as sensitive as aquatic phase 

amphibians.

Metsulfuron-methyl

Acute toxicity studies using rainbow trout and bluegill (USDA FS, 2005) show that 

metsulfuron-methyl is practically nontoxic to fish with 96-hour LC50 values >150 mg/L. 

Sublethal effects including erratic swimming behavior, laying on the bottom, lethargy 

and color changes that were observed in rainbow trout with a reported NOEC of 10 mg/L. 

The 90-day chronic exposure study in rainbow trout including fish, egg, and fry (USDA 

FS, 2005) reported no effects on rainbow trout hatching, larval survival, or larval growth 

at a concentration of up to 4.7 mg/L. The study reported a LOEC of 8 mg/L with 

decreases in hatching and survival of fry. The acute and chronic fish toxicity data for 

metsulfuron-methyl is summarized in table 3-4.

No information is available regarding the toxicity of metsulfuron-methyl to amphibian 

species.

Table 3-4. Acute and chronic fish toxicity data for metsulfuron-methyl.

Test Organism Endpoint/Length Toxicity Value

(mg/L)

NOEC 

(mg/L)

Acute

Rainbow trout 96-hour LC50 >150 100

Bluegill sunfish 96-hour LC50 >150 150

Bluegill sunfish 96-hour LC50 >1000 1000

Rainbow trout 96-hour LC50 >1000 10

Chronic 

Rainbow trout 90-days NR 4.7 (LOEC: 8.0)

NR = Not reported Source: USDA FS, 2005
3.2.1.2 Aquatic Invertebrates

Triclopyr and TCP

Triclopyr acid and TEA are less toxic to aquatic invertebrates compared to triclopyr BEE 

(USDA FS, 2011a). TCP appears to be less toxic than triclopyr BEE, but more toxic than 

triclopyr acid and TEA to aquatic invertebrates. The aquatic invertebrate studies show 

that the triclopyr acid and TEA are practically nontoxic to non-bivalve aquatic 

invertebrate species with acute LC50 values >100 mg/L. Triclopyr TEA is slightly toxic 

to bivalve test species with an acute median LC50 of 19.7 mg/L. One study using TCP 

shows that TCP is slightly toxic to Daphnia magna with an acute LC50 of 10.9 mg/L. 

Triclopyr BEE and Garlon® 4 are moderately toxic to aquatic invertebrates with an acute 

median LC50 value of 2.9 mg/L. Triclopyr BEE and Garlon® 4 are highly toxic to

bivalves with acute EC50 values between 0.1 and 1 mg/L based on shell deposition. The 

acute triclopyr and TCP toxicity data for aquatic invertebrates are summarized in table 3-

5.

Table 3-5. Acute aquatic invertebrate toxicity data for triclopyr and TCP

Test Organism Endpoint/Length Toxicity Value 

(mg a.e./L)

NOEC 

(mg a.e./L)

Triclopyr Acid and TEA (Non-bivalve)

Grass shrimp 48-hour LC50 103.7 NR

Daphnia magna (Acid) 48-hour LC50 132.9 NR

Pink shrimp 48-hour LC50 270.5 NR

Physella gyrina (Acid) 48-hour LC50 293 NR

Daphnia magna 48-hour LC50 346 NR

Daphnia magna 48-hour LC50 357 NR

Daphnia magna 48-hour LC50 376 <108

Daphnia magna 48-hour LC50 837 NR

Red swamp crayfish 48-hour LC50 6397.5 NR

Median: 401.6

Triclopyr TEA (Bivalves)

Eastern oyster 96-hour EC50 (shell dep) 18.4 NR

Eastern oyster 48-hour EC50 (abnormal 

development)

21.1 NR

Median: 19.7

TCP 

Daphnia magna 48-hour LC50 10.9 NR

Triclopyr BEE and Garlon® 4 (Arthropods)

Daphnia magna 48-hour LC50 0.25 NR

Daphnia pulex 48-hour LC50 0.54 NR

Grass shrimp 96-hour LC50 0.77 NR

Daphnia magna 48-hour LC50 1.2 NR

Grass shrimp 96-hour EC50 1.8 NR

Red swamp crayfish 48-hour LC50 3.1 1.2

Stonefly (Calineuria 

californica)

48-hour LC50 3.6 NR

Appendix E. Herbicide Environmental Risk Assessment
Test Organism Endpoint/Length Toxicity Value 

(mg a.e./L)

NOEC 

(mg a.e./L)

Mayfly (Ameletus sp.) 48-hour LC50 3.8 NR

Caddisfly (Brachycentrus 

americanus)

48-hour LC50 5 NR

Daphnia magna 48-hour LC50 8.3 NR

Mayfly (Cinygma sp.) 48-hour LC50 8.95 NR

Caddisfly (Psychoglypha 

sp.)

48-hour LC50 12.5 NR

Caddisfly (Lepidostoma 

unicolor)

48-hour LC50 20 NR

Median: 2.9

Triclopyr BEE and Garlon 4 (Bivalves)

Eastern oyster* 96-hour EC50 (shell dep.) 0.14 0.05

Eastern oyster 96-hour EC50 (shell dep.) 0.33 NR

Median: 0.21

*Garlon® 4 NR = not reported Source: USDA FS, 2011a

Chronic toxicity to aquatic invertebrates has been assessed for triclopyr TEA and TCP. 

The 21-day D. magna study for triclopyr TEA reported a NOEC of 25 mg a.e./L and a 

LOEC of 46.2 mg a.e./L based on total number of young and mean brood size (USEPA, 

2009). The chronic study using D. magna and TCP reported a NOEC of 0.058 mg 

TCP/L and a LOEC of 0.13 mg TCP/L based on a significant decrease in the mean 

number of young (USDA FS, 2011a).

A series of 1-hour field exposure studies and triclopyr BEE in several species of stream

invertebrates show that the LC50 values for these aquatic invertebrates were greater than 

PJ/§200 mg a.e./L) (Kreutzweiser et al., 1992). The LC50 values from the 1-hour 

field studies are two orders of magnitude higher than the standard 48-hour LC50 values 

for triclolpyr BEE suggesting those species are less sensitive.

Imazapyr

The acute toxicity data for aquatic invertebrates show that imazapyr acid and 

isopropylamine salt of imazapyr are practically non-toxic to D. magna (USEPA, 2005b;

USEPA, 2007) and saltwater invertebrates—i.e., oysters and pink shrimp (USEPA,

2005b). The bioassays using D. magna indicate that the Arsenal® herbicide formulation 

is slighty toxic to aquatic invertebrates (more toxic than either imazapyr acid or the 

isopropylamine salt of imazapyr). The EC50 of 79 mg a.e./L for Arsenal® to D. magna is 

less than the EC50 of >100 mg a.e./L for imazapyr acid to D. magna, and the EC50 of 614 

mg a.e./L for isopropylamine salt of imazapyr (USDA FS, 2011b). The acute aquatic 

invertebrate toxicity data for imazapyr is summarized in table 3-6.
Table 3-6. Acute and chronic aquatic invertebrates toxicity data for imazapyr

Test Organism Endpoint/Length Toxicity 

Value

(mg a.e./L)

NOEC 

(mg a.e./L)

Imazapyr Acid

Daphnia magna 24-hour EC50 >100 NR

48-hour EC50 >100 NR

Eastern oyster 96-hour EC50 >100 132

Eastern oyster 96-hour EC50 NR 109 (LOEC: 173)

Pink shrimp 96-hour LC50 >189 189

Daphnia magna 21-day LC50 >97.1 97.1

Imazapyr IPA Salt

Daphnia magna 48-hour EC50 614 NR

Arsenal® Herbicide 

Daphnia magna 48-hour LC50 79.1 40.68 (LOEC: 81.36) 

NR = Not reported Source: USDA FS, 2011b.

A long-term toxicity study using D. magna and imazapyr reported no effects at 

concentrations up to 97.1 mg a.e./L. Similar to fish, the chronic NOEC in daphnids is 

above the acute NOEC of 40.68 mg a.e./L for Arsenal® herbicide. A mesocosm study 

was conducted to assess the long-term impacts of formulated imazapyr to aquatic 

invertebrates (Fowlkes et al. 2003). In this study, mixed macroinvertebrate species were 

exposed to mesocosms treated with Arsenal Applicators Concentrate® at concentrations 

of 0.184, 1.84, or 18.4 mg a.e./L. After a 2-week exposure period (comparable to the 

exposure period in the chronic daphnid studies), no impacts were noted on species 

richness or abundance. The NOEC of 18.4 mg a.e./L from the mesocosm study is 

consistent with the acute NOEC of 40.68 mg a.e./L for Arsenal® herbicide and the 

chronic NOAEC of 97.1 mg a.e./L in daphnids. However, USEPA considered the results 

of the mesocosm study are of limited value because potential effects at the species level 

were not examined (USEPA, 2007; USDA FS, 2011b).

Metsulfuron-methyl

Acute toxicity studies using D. magna show that metsulfuron-methyl is practically nontoxic to aquatic invertebrates with 48-hour EC50 values for immobility ranging from >150 

mg/L to 720 mg/L (USDA FS, 2005). The acute NOECs ranged from 150 to 420 mg/L. 

The 21-day chronic toxicity studies using D. magna reported NOECs ranging from 100 to 

150 mg/L for survival, reproduction, and immobility, and a lower NOEC of 17 mg/L for 

growth. The acute and chronic aquatic invertebrate toxicity data for metsulfuron-methyl 

are summarized in table 3-7.

Appendix E. Herbicide Environmental Risk Assessment
Table 3-7. Acute and chronic aquatic invertebrate toxicity data for metsulfuron-methyl

Test Organism Endpoint/Length Toxicity Value

(mg/L)

NOEC 

(mg/L)

Acute

Daphnia magna 48-hour EC50 >150 150

Daphnia magna 48-hour EC50 720 420

Chronic 

Daphnia magna 21-days NR >150 (reproduction)

(LOEC: >150)

17 (growth)

Daphnia magna 21-days NR 100

NR = Not reported Source: USDA FS, 2005

3.2.1.3 Aquatic Plants

Triclopyr and TCP

Aquatic plant studies using blue green algae, freshwater diatoms, and green algae testing 

technical and formulated material have demonstrated that triclopyr TEA and BEE, and 

TCP, are moderately toxic (EC50 >1 to 10 mg/L) to slightly toxic (EC50 >10 to 100 mg/L) 

except for three test species (USDA FS, 2011a; USEPA, 2009). Triclopyr TEA is highly 

toxic to green algae Ankistrodesmus spp. and triclopyr BEE is very highly toxic to 

diatoms Navicula pelliculosa and Skeletonema costatum. These studies also show that 

triclopyr acid is the least toxic, and triclopyr BEE is the more toxic form of triclopyr to 

algae and diatoms compared to triclopyr TEA (table 3-8). 

Table 3-8. Acute aquatic plant (algae) toxicity data for triclopyr and TCP.

Test Organism Endpoint/Length Toxicity Value

(mg a.e./L)

NOEC 

(mg a.e./L)

Triclopyr Acid

Chlorella vulgaris 11 NR

Chlorella pyrenoidosa 80 NR

Kirchneria subcapitata 120-hour EC50 32.8 7

Selanastrum capricornutum 120-hour EC50 50 22

Triclopyr TEA

Chlorella vulgaris 8 NR

Chlorella pyrenoidosa 54 NR

Ankistrodesmus spp. 96-hour EC50 0.49 0.23

Kirchneria subcapitata 96-hour EC50 5.4 8.1

Skeletonema costatum 96-hour EC50 4.6 0.39

Navicula pelliculosa 96-hour EC50 10.6 5.54

Kirchneria subcapitata 120-hour EC50 12.1 NR

Anabaena flos-aquae 168-hour EC50 4.1 1.39

Triclopyr BEE

Anabaena flos-aquae 96-hour EC50 1.42 0.37

Navicula pelliculosa 96-hour EC50 0.073 0.0014

Skeletonema costatum 96-hour EC50 0.84 0.15
Skeletonema costatum 120-hour EC50 5.9 1.0

Kirchneria subcapitata 120-hour EC50 2.5 NR

TCP

Kirchneria subcapitata 120-hour EC50 1.8 0.65

Anabaena flos-aquae 120-hour EC50 1.8 0.36

NR = Not reported. Source: USDA FS, 2011a

Aquatic plant studies using macrophytes have demonstrated that triclopyr acid, triclopyr 

TEA (to monocots), and triclopyr BEE (to both monocots and dicots) are moderately toxic 

with 7- or 14-day median EC50 values between 1 and 10 mg/L. Triclopyr acid and triclopyr 

TEA are very highly toxic to dicots with median EC50 values <0.1 mg/L (see table 3-9).

Table 3-9. Aquatic plant (macrophytes) toxicity data for triclopyr

Test Organism Endpoint/Length Toxicity Value

(mg a.e./L)

NOEC 

(mg a.e./L)

Triclopyr Acid and Triclopyr TEA

Monocots

Lemna gibba 14-day EC50 6.06 2.5

Lemna gibba 14-day EC50 7.6 2.5

Lemna gibba 14-day EC50 7.8 2.5

Lemna gibba 14-day EC50 13.58 NR

Lemna minor 14-day EC50 15.8 NR

Median: 9.47

Dicots

Watermilfoil (acid) 14-day EC50 0.04 NR

Watermilfoil (TEA) 5-week EC50 0.04 0.01

Milfoil Hybrid 5-week EC50 0.08 0.03

Watermilfoil (acid) 14-day EC50 0.56 NR

Median: 0.09

Triclopyr BEE

Monocots

Lemna gibba 14-day EC50 0.86 <0.111

Lemna gibba 14-day EC50 6.25 NR

Median: 2.32

Dicots

Watermilfoil 14-day EC50 1.49 NR

Watermilfoil 14-day EC50 4.62 NR

Median: 2.62

NR = Not reported Source: USDA FS, 2011a

Imazapyr

Imazapyr is more toxic to aquatic macrophytes than algae based on available EC50 values. 

Toxicity data for blue-green algae, green algae, and diatoms show that imazapyr is 

slightly toxic to algae (7-day EC50 ranging from 11.5 to 92 mg a.e./L) (USDA FS,

2011b). The toxicity data for duckweed and watermilfoil show that imazapyr is very 

Appendix E. Herbicide Environmental Risk Assessment
highly toxic to macrophytes (7- or 14-days EC50 ranging from 0.018 to 0.029 mg a.e./L) 

(USDA FS, 2011b) (table 3-10). 

Table 3-10. Aquatic plants (algae and macrophytes) toxicity data for imazapyr

Test Organism Endpoint/Length Toxicity Value

(mg a.e./L)

NOEC 

(mg a.e./L)

Algae

Imazapyr Acid

Green algae (Selenastrum 

capricornutum)

7-day EC50 71 50.9

Blue-green algae (Anabaena 

flosaquae)

7-day EC50 12.2 9.6

Freshwater diatom (Navicula 

pelliculosa)

7-day EC50 >41 41

Marine diatom (Skeletonema 

costatum)

7-day EC50 92 15.6

Imazapyr IPA Salt

Green algae (Selenastrum 

capricornutum)

7-day EC50 11.5 7.16

Macrophytes

Imazapyr Acid

Duckweed 

(Lemna gibba)

14-day EC50 0.024 0.01

Imazapyr IPA Salt

Duckweed (Lemna gibba) 7-day EC50 0.018 0.011

Arsenal®

Water milfoil (Myriophyllum 

sibiricum)

14-day EC50 0.029 NR

NR = Not reported Source: USDA FS, 2011b

Metsulfuron-methyl

Two 14-day toxicity studies using duckweed and northern watermilfoil demonstrate high 

toxicity from exposure to metsulfuron-methyl. The duckweed study reported a 14-day 

EC50 value of 0.36 μg/L based on chlorosis of fronds and a NOEC value of 0.16 μg/L.

The northern watermilfoil study reported a 14-day EC50 value of 0.22 μg/L based on a 

decrease in dry root mass (USDA FS, 2005) (table 3-11).

The toxicity studies in algae show that metsulfuron-methyl is less toxic to algae 

compared to aquatic macrophytes. The 120-hour or 72-hour EC50 values for algae range 

from >95.4 to 1,560 μg/L with effects on cell density, growth rate, and growth inhibition. 

The NOEC values from the algae studies range from 10 to 125 μg/L.

A toxicity study using aquatic cyanobacteria reported significant growth inhibition at a 

metsulfuron-methyl concentration of 3 μg/L (Peterson et al., 1994).
Table 3-11. Aquatic plants (algae and macrophytes) toxicity data for metsulfuron-methyl.

Test Organism Endpoint/Length Toxicity Value

(μg/L)

NOEC 

(μg/L)

Algae

Green algae*

(Selenastrum 

capricornutum)

Cell inhibition/120-hour EC50 NR 10

Blue-green algae* 

(Anabaena flosaquae)

120-hour EC50 >95.4 <95.4

Freshwater diatom*

(Navicula pelliculosa)

Growth rate/120-hour EC50 >95.4 95.6

Green algae (Selenastrum 

capricornutum)

Growth inhibition/72-hour 

EC50

1,560 NR

Green algae (Selenastrum 

capricornutum)

Cell density/72-hour EC50

Area under the growth 

curve/72-hour EC50

Growth Rate/72-hour EC50

372

359

1307

125

125

125

Green algae (Chlorella 

pyrenoidosa)

Growth inhibition/96-hour 

EC50

620 NR

Macrophytes

Duckweed 

(Lemna gibba)

14-day EC50 0.36 0.16

Watermilfoil 

(Myriophyllum sibiricum)

14-day IC50 0.22 NR

* Ally® herbicide. NR = Not reported Source: USDA FS, 2005

3.2.2 Terrestrial Effects Analysis

3.2.2.1 Mammals

Available mammalian data discussed in the human health section of this risk assessment 

can be used as a surrogate to evaluate the potential effects to wild mammals. In general 

mammalian toxicity is low for triclopyr, imazapyr, and metsulfuron-methyl. Specific 

information regarding the acute and chronic effects of each herbicide can be found in 

section 2.4 of this risk assessment.

3.2.2.2 Birds 

Triclopyr

Triclopyr is considered practically non-toxic to slightly toxic to birds based on studies 

using the mallard and quail (USEPA, 1998; USDA FS, 2011a). The acute oral toxicity of 

triclopyr varies from 529 to 1,698 mg a.e./kg in mallard duck, and northern bobwhite 

quail (table 3-12). Reproduction studies in mallard and bobwhite quail report a NOEC of 

approximately 100 ppm and a LOEC of 200 ppm for both species. The acute dietary 

study reported a NOEC of 1,000 ppm in Japanese quail. A long-term NOEC of 50 ppm 

was determined in Zebra finches for triclopyr BEE.

Appendix E. Herbicide Environmental Risk Assessment
Table 3-12 Acute toxicity of various forms of triclopyr to birds.

Test Species LD50/LC50 NOEC LOEC

Acute oral/gavage

Mallard duck 

triclopyr acid 1,698 mg/kg/day 464 mg/kg bw (mortality) NA

triclopyr TEA 1,418 mg/kg/day NA NA

Northern bobwhite quail

triclopyr BEE 529 mg a.e./kg bw §PJ a.e./kg bw (mortality)/

§PJDHNJEZ

(toxicity) 

§PJDHNJEZ

TCP (99.9%) >2,000 mg a.i./kg bw 125 mg/kg bw 250 mg/kg bw

(reduced body weight)

Acute dietary

Japanese quail

triclopyr acid 3,272 ppm (LC50) 1,000 ppm

§PJDHNJEZ

2,000 ppm

§PJDHNJEZ

Northern bobwhite quail

triclopyr acid §PJDHNJEZ

(LC50)

§PJDHNJEZ

(mortality)

NA

triclopyr TEA SSPDH§PJ

a.e./kg bw) (LC50)

2,150 ppm formulation (995 

mg a.e./kg bw)

NA

triclopyr BEE 

(96.1% a.i.)

5,401 ppm a.i. (3,885 ppm 

a.e.) (LC50)

SSPDL§SSPDH

(toxicity)

1,711 ppm a.i. (reduced 

weight gain)

Mallard duck

triclopyr acid 5,620 ppm (LC50) NA NA

triclopyr TEA 4,464.8 ppm a.e. (LC50) NA NA

triclopyr BEE 

(93% a.i.)

>6,689 ppm a.e. (LC50) SSP§PJDHNJ

bw)

4,640 ppm, 

reduced food 

consumption and bw gain

triclopyr BEE 

(96.1% a.i.)

>3,885 ppm a.e. (1087.8 

mg a.e./kg bw) (LC50)

961 ppm a.i. (246 mg a.e./kg 

bw/day)

1,711 ppm a.i. §PJ

a.e./kg bw/day) (reduced 

body weight gain)

TCP >5,620 ppm ( LC50) NA 562 ppm (reduced body 

weight gain)

Reproductive Studies

Mallard duck

triclopyr acid 

(98.9% a.i.)

100 ppm (10 mg/kg bw/day) 200 ppm (20 mg/kg 

bw/day)

Northern bobwhite quail

triclopyr acid 

(98.9% a.i.)

100 ppm §PJDHNJ

bw) 

SSP§PJDHNJ

bw)

NA – Not available. Source: USDA FS, 2011a

Field studies using triclopyr applications in Forest Service programs did not cause 

adverse effects in birds (Boren et al., 1993; Schulz et al., 1992a,b). Benefits were 

observed in some cases where certain bird species benefited from changes in vegetation. 
Based on the acute gavage LD50 (>2,000 mg/kg bw) for TCP in bobwhite quail, TCP is 

less toxic than triclopyr acid, triclopyr TEA, or triclopyr BEE. The NOAEL of 125 

mg/kg bw for TCP is similar to the NOAEL of ؆126 mg a.e./kg bw for triclopyr BEE. 

The dietary LC50 for TCP in mallards is >5,620 ppm suggesting it is practically non-toxic 

with a reduced body weight gain noted at 562 ppm. 

Imazapyr

Imazapyr has low acute toxicity to birds based on available avian studies. The acute 

gavage studies with single oral doses of imazapyr acid resulted in no signs of toxicity at a 

dose of 2,510 mg a.e./kg bw in either quail or ducks (USEPA, 2007). The study using the 

Arsenal® herbicide formulation also caused no signs of toxicity at doses up to 2,150 mg 

formulation/kg bw, equivalent to about 486 mg a.e./kg bw. The acute NOAEL was the

highest dose tested based on a lack of adverse effects. Results of these studies suggest 

imazapyr is considered practically non-toxic to birds.

The longer-WHUP§ZHHNUHSURGXFWLRQVWXGLHVusing the imazapyr acid indicate no 

adverse effects following exposures to dietary concentrations of up to 2,000 ppm a.e.

(USDA FS 2011a). 

A field study reported no changes in bird populations after imazapyr was applied at about 

3.7 lb a.e./acre for site preparation (Brooks et al., 1995). The visual surveys did not note

any impacts on bird diversity, relative to sites treated with picloram, triclopyr, or 

hexazinone. Another field study indicated that imazapyr can improve bobwhite quail 

habitat by controlling hardwood establishment in pine stands (Welch et al., 2004). 

There was a reported bird kill incident in Aiken County, South Carolina from spraying a

mixture of herbicides (imazapyr, diuron, and metsulfuron-methyl) on fence rows that 

may have drifted onto adjacent bird nest boxes. Imazapyr, as well as diuron and

metsulfuron-methyl, were used in the incident and no definitive link to the herbicide 

treatments could be made (USDA FS, 2011b). 

Metsulfuron-methyl

Metsulfuron-methyl has low avian acute toxicity based on acute and subchronic toxicity 

studies conducted in bobwhite quail and mallards (USDA FS, 2005). The 14-day oral 

LD50 of technical grade metsulfuron-methyl administered by gavage in adult bobwhite 

quail was >2,250 mg/kg. The 5-day dietary exposure of juvenile ducks and quail to 

technical grade metsulfuron-methyl at concentrations ranging from 292 to 5,620 ppm did 

not result in any. observable toxicity. The only sign of toxicity following a 5-day dietary 

metsulfuron-methyl exposure of 3,160 ppm to 10-day-old bobwhite quail and 5,620 ppm 

to 8-day old mallard was weight loss. The NOAELs for weight loss ranged from 1,780 to 

3,160 ppm in both studies. 

Two 23-week feeding studies on reproductive effects for metsulfuron-methyl in bobwhite 

quail and mallards reported a NOAEL of 1,000 ppm (the highest dose tested) for chronic 

dietary exposure (USDA FS, 2005).

Appendix E. Herbicide Environmental Risk Assessment
3.2.2.3 Reptiles and Amphibians (terrestrial phase)

No information regarding the toxicity of imazapyr to reptiles or terrestrial-phase 

amphibians was identified in the open literature or in studies submitted to the USEPA 

(USEPA, 2005b; 2006; 2007). The USEPA ecological risk assessment for imazapyr 

includes a risk evaluation to terrestrial phase amphibians using birds as a surrogates for 

terrestrial phase amphibians and reptiles (USEPA, 2005b). The same approach is used in 

the USEPA risk assessment for the California red legged frog (USEPA, 2007). The 

permeability of amphibian skin to pesticides and other chemicals is a concern for this 

approach. No data is available on the permeability of amphibian skin to imazapyr.

Quaranta et al. (2009) noted that the skin of the frog R. esculenta is much more 

permeable to three pesticides (atrazine, paraquat, and glyphosate) than the skin of pig ear 

due to the differences in the structure and function of amphibian skin relative to

mammalian skin. 

An open literature search did not identify any reptile toxicity studies using metsulfuronmethyl but identified one study on the toxicity of metsufluron-methyl to terrestrial-phase 

amphibians (Lajmanovich et al., 2013). The study determined the individual toxicity of 

herbicide formulations contining glyphosate, metsulfuron-methyl, bispyribac-sodium, 

and picloram, and compared the mixture toxicity of three binary combinations 

(glyphosate and metsulfuron-methyl, glyphosate and bispyribac-sodium, glyphosate and 

picloram) on Rhinella arenarum tadpoles. The 48 hour LC50 for metsulfuron-methyl is 

105.56 mg a.i./L. The NOEC and LOEC for metsulfuron-methyl were 80 mg a.i./L and 

160 mg a.i./L, respectively. 

3.2.2.4 Terrestrial Invertebrates and Microorganisms

Terrestrial Invertebrates

USEPA/OPP (1998) classifies triclopyr as practically non-toxic to bees based on the 

results of acute contact toxicity studies in honey bees using triclopyr acid and triclopyr 

TEA (contact LD50 values >ȝJEHH7KHFRQWDFW/'50 for triclopyr BEE to the honey

EHHLVUHSRUWHGDV!ȝJEHHsuggesting low toxicity (USEPA, 2009). 

The acute (14 day) toxicity studies in earthworms using triclopyr, triclopyr TEA, 

triclopyr BEE, and Garlon® 4 indicate that triclopyr acid is the least toxic to earthworms 

with an NOAEL of approximately 790 ppm a.e. ( i.e., 790 mg a.e./kg soil dry weight), 

and an LC50 of 1,110 ppm a.e. (USDA FS, 2011a). Triclopyr TEA is the most toxic form 

of triclopyr to earthworms with an LC50 of about 146 ppm a.e., and an LOAEC of 134 

ppm a.e. based on a significant increase in mortality (35% relative to 0% in the control 

groups) and a significant decrease in body weight (17%) relative to the control group.

This study suggests that triclopyr TEA may be moderately toxic to earthworms relative to 

triclopyr acid.

A chronic 56-day earthworm bioassay testing Garlon® 4 showed no adverse effects on 

reproduction or growth at a concentration of 6.9 ppm a.e. (USDA FS, 2011a). The study 

on the impacts of Garlon® 3A to earthworms and other invertebrates at an application rate 
RINJDLKD§OEDHDFUHWRWXUISORWVVKRZHGFRQVLVWHQWUHVXOWVZLWKQR

significant reduction in mixed earthworm populations, mites, springtails, or ants in turf 

and soil core samples (Potter et al. 1990).

A series of field studies using triclopyr in broadcast applications suggested some effects 

to terrestrial invertebrates including beetles, butterflies, and spiders (USDA FS, 2011a). 

These effects are considered secondary because they were attributable to changes in 

vegetation cover, similar to changes in invertebrate populations observed with other 

vegetation management methods, instead of the potential toxic effect of triclopyr. 

Imazapyr has low acute toxicity to to the honey bee based on the acute contact LD50 of 

JUHDWHUWKDQȝJEHHZKLFKLVHTXLYDOHnt to about 860 mg/kg bw (USEPA, 2005b;

2007). There is no information available on other potential subchronic or non-lethal 

effects in bees or other invertebrate species. 

Honey bee toxicity studies using metsulfuron-methyl indicate that the acute LD50 is 

JUHDWHUWKDQȝJEHHDQGSRVVLEO\JUHDWHUWKDQȝJEHH, suggesting very low toxicity 

(USDA FS, 2005). These values correspond to doses ranging from about 270 to 1,075

mg/kg (0.025 mg/0.000093 kg to 0.1 mg/0.000093 kg) using a body weight of 0.093 g for 

the honey bee (USDA APHIS, 1993).

A toxicity study on three insect species (large white butterfly, beetle, and grain aphid) 

placed on plants sprayed with metsufuron-methyl at an application rate of 0.00004 to 

0.003 lbs a.i./acre showed no adverse effects on survival or larval growth rate (Kjaer and 

Heimbach, 2001).

Terrestrial Microorganisms 

Triclopyr is unlikely to have an impact on soil microorganisms (i.e., soil microbial 

function or community structure) based on studies on growth inhibition of fungi species

(Chakravarty and Sidhu, 1987; USDA FS, 2011a). A study of Garlon® 4 (Estok et al.,

1989) indicated a significant reduction of radial growth in fungi species at concentrations 

,SSPZLWKWRWDOJURZWKLQKLELWLRQDW,000 ppm. The slowest growing fungus 

was the least sensitive to triclopyr. Triclopyr TEA did not show any impacts on soil 

microbial function or community structure at an application rate of 1.9 kg a.i./ha 

(Houston et al., 1998). 

Information on effects on terrestrial microorganisms is not available for imazapyr 

(USEPA, 2005b; 2007). Metsulfuron-methyl studies showed that at a concentration of 5 

ppm in culture inhibited the growth of several strains of Pseudomonas (USDA FS, 2005). 

The inhibition of terrestrial microorganisms was attributed to ALS inhibition because 

terrestrial microorganisms have an enzyme involved in synthesis of branched chain 

amino acids. This enzyme is functionally equivalent to the target enzyme in terrestrial 

macrophytes. 

Appendix E. Herbicide Environmental Risk Assessment
3.2.2.5 Terrestrial Plants

Triclopyr

Triclopyr causes uncontrolled abnormal growth in plants by mimicking indole auxin 

plant growth hormones. It is a selective herbicide that is most toxic to broadleaf plants 

(Lewer and Owen, 1990). Triclopyr is effective in the control of dicots and relatively 

ineffective in controlling monocots through foliar application (USDA FS, 2011a). 

The vegetative vigor studies in non-target plants from direct foliar application to young 

plants indicate that triclopyr TEA and triclopyr BEE have similar toxicities to a range of 

species (sunflower, sugar beet, tomato, oilseed rape, radish, soybean, wheat, corn, and 

onion for triclopyr TEA, and alfalfa, carrots, corn, oats, onions, radishes, soybeans, 

sunflowers, tomatoes, and wheat for triclopyr BEE). The sunflower (a dicot) is the most 

sensitive species for both TEA (EC25 = 0.005 lb a.e./acre) and triclopyr BEE (EC25 

§OEDHDFUHWheat and oats (monocots) are much more tolerant with EC25

values in excess of 0.3 lb a.e./acre for triclopyr TEA and triclopyr BEE (USDA FS,

2011a). The range of NOECs for triclopyr TEA ranges from 0.0028 lb a.e./acre testing 

sunflowers and soybeans to 0.23 lb a.e./acre for barley based on effects to shoot length 

(USEPA, 2009). The NOECs in alfafa, carrots, corn, oats, onions, radishes, soybeans, 

sunflowers, tomatoes, and wheat from triclopyr BEE exposure, based on shoot length and 

shoot weight effects, range from 4.4 g a.i./ha (sunflowers for shoot length, and carrots 

and sunflowers for shoot weight) to >2,242 g a.i./ha (oats). The NOECs from another 

study using triclopyr BEE were <0.063 lb a.e./acre (onions) and 0.028 lb a.e./acre 

(sunflowers) (USEPA, 2009). 

The seedling emergence studies indicate that triclopyr BEE is about equally effective 

against dicots and at least some monocots. Triclopyr BEE is much more toxic than 

triclopyr TEA in some species. For example, the EC25 in alfafa for triclopyr BEE is 40 g 

DLKD§OEDHDFUHwhich is much lower than the EC25 values for triclopyr TEA 

for all tested species (>0.23 lb a.e./acre). The higher phytotoxicity of triclopyr BEE may 

relate to faster absorption compared to triclopyr TEA that has been reported in

chickweed, wheat, and barley (Lewer and Owen 1990). Variation in species sensitivity to 

triclopyr BEE may directly relate to the plant’s rate of metabolic ester hydrolysis (Lewer 

and Owen, 1990). 

Field studies using triclopyr have shown some adverse impacts at high application rates

and using broadcast applications. The field studies in various conifer species show that 

these species tend to be tolerant to triclopyr exposure in spring (April and May) and after 

fall dormancy (September) (USDA FS, 2011a). 

Exposure to triclopyr drift may cause long-term impacts on some bryophyte and lichen 

communities (Newmaster et al., 1999). Some Forest Service events suggested that 

volatilization of triclopyr BEE may damage nontarget plants if it is applied under a 

poorly ventilated canopy and high temperatures. However, none of the field studies 

involving triclopyr BEE documented damage to nontarget plant species through 

volatilization (USDA FS, 2011a).
Imazapyr 

Imazapyr inhibits acetolactate synthase, an enzyme that catalyzes the biosynthesis of 

branched-chain amino acids essential for protein synthesis and plant growth (USDA FS,

2011b). After foliage application, imazapyr is rapidly transported by the phloem from 

the treated leaves to the roots . Imazapyr has the potential to induce allelopathic effects;

however, the potential for allelopathic effects may not substantially increase the risk to 

non-target plants because its movement in soil is relatively rapid (USDA FS, 2011b).

The bioassays for vegetative vigor (i.e., post-emergence applications) and seedling 

emergence (i.e., pre-emergence applications) in response to foliar applications of 

imazapyr indicate that dicots are more sensitive to imazapyr than monocots. The 

differences between dicots and monocots are greater in the vegetative vigor assays 

compared to the seedling emergence studies. In the vegetative vigor assays, the EC25 of 

the most sensitive dicot, cucumber (0.0009 lb a.e./acre) is about a factor of 13 below the 

EC25 of the most sensitive monocot, wheat (0.012 lb a.e./acre). The NOAECs for the 

acid (22.6% a.e.) for dicots range from 0.000064 lb a.e./acre in cucumber to 0.0039 lb 

a.e./acre in sunflower, and for monocots range from 0.0039 lb a.e./acre in wheat and oat,

to 0.0078 lb a.e./acre in corn. The NOAECs for the isopropylamine salt for dicots are 

0.001 lb a.e./acre in sugar beet and 0.008 lb a.e./acre in soybean, and for monocots is 

0.005 lb a.e./acre in onion. In seedling emergence assays, the EC25 of the most sensitive 

dicot, sugar beet (0.0024 lb a.e./acre) is a factor of approximately 2 below the most 

sensitive monocot species, wheat (0.0046 lb a.e./acre). The NOAECs for imazapyr acid 

(22.6% a.e.) in dicots are 0.00017 lb a.e./acre in sugar beet and 0.0003 lb a.e./acre in 

tomato, and in monocots range from 0.00099 lb a.e./acre in wheat to 0.0156 lb a.e./acre in 

oat. For the most sensitive species of dicot, foliar applications (vegetative vigor) are 

more toxic than soil exposures (seedling emergence) by about a factor of about 2.6, and 

vice versa for the most sensitive species of monocot (USDA FS, 2011b; USEPA, 2005b). 

Metsulfuron-methyl

Metsulfuron-methyl inhibits acetolactate synthase, an enzyme that catalyzes the 

biosynthesis of three branched-chain amino acids (valine, leucine, and isoleucine) 

essential for plant growth.

Laboratory toxicity studies (pre- and post-emergence bioassays) using metsulfuronmethyl to evaluate the effects to terrestrial plants by a direct application has been 

evaluated for 10 species of plants including both dicots (soybean, cocklebur, cotton, 

morningglory, wild buckwheat, and sugar beet) and monocots (corn, barnyardgrass, rice,

and nutsedge) (USDA FS, 2005). The study results showed that the most sensitive 

species was the morningglory with 70% growth inhibition at pre-emergence applications 

of about 0.00022 lbs a.i./acre. At the same application rate, the cocklebur and sugar beet 

showed 20% and 40% growth inhibition, and rice was the only monocot to respond with 

20% inhibition. All of the plants showed 60 to 100% growth inhibition at an application 

of 0.014 lbs a.i./acre which is approximately a factor of two below the typical application 

rate used by the Forest Service (0.03 lb/acre).

Other laboratory toxicity studies on pre-emergence and post-emergence were performed 

in corn, cucumber, onion, pea, rape, sugar beet, sorghum, soybean, tomato, and wheat 

Appendix E. Herbicide Environmental Risk Assessment
(USDA FS, 2005). The pre-emergence assay showed that the most sensitive species were 

cucumber and onion with a NOEC of 0.000037 lb/acre, and the most tolerant species was 

wheat with a NOEC of 0.0056 lb/acre. The post-emergence assay showed that the 

cucumber was also the most sensitive species, with a NOEC of 0.000037 lb/acre, and the 

most tolerant species was wheat with a NOEC of 0.0039 lb/acre. 

Field studies have shown that the lowest application rate associated with adverse effects 

(a decreased yield of both tomatoes and onions) was 0.1 g/ha (USDA FS, 2005;

Obrigawitch et al., 1998), which is similar to the LOEC of 0.25 g/ha reported for other

dicots. The most tolerant species in the field studies (Obrigawitch et al., 1998) consisted 

of various grasses for which NOEC values based on crop yield ranged up to 6 g/ha 

(NOEC values for wheatgrass and bromegrass). The NOEC value of 6 g/ha is equivalent 

to an application rate of about 0.0054 lb/acre, which is identical to the NOEC value for 

wheat (0.0056 lb/acre).

4.0 EXPOSURE ASSESSMENT

4.1 Human Health Exposure Assessment

Exposure assessments estimate the potential exposure of humans to triclopyr, imazapyr, and 

metsulfuron-methyl. The exposure assessment begins with the use and application methods of 

triclopyr, or triclopyr mixed with imazapyr and metsulfuron-methyl products. An identified 

exposure pathway for each herbicide includes (1) a release from a source, (2) an exposure point 

where contact can occur, and (3) an exposure route such as ingestion, inhalation, or dermal 

contact by which contact can occur (USEPA, 1989). Exposures for the identified human 

populations are qualitatively evaluated for each identified exposure pathway.

4.1.1 Identification of Potentially Exposed Human Populations and Complete 

Exposure Pathways

Under the expected use pattern and the proposed application methods (manual painting or 

direct spray treatment using a backpack sprayer), workers in the program who mix and apply 

the herbicides in the field are the most likely human population with the potential to be 

exposed to these compounds. Dermal exposure may occur from both the manual painting 

application and backpack spray application as well as and spill/splashing-during mixing and 

loading herbicide into the containers used during application. Exposure during transportation 

is not anticipated because the container of the concentrated material is sealed. Following 

label directions including the use of proper PPE will minimize exposure to workers. 

Accidental exposure may occur during mixing and applying the formulations. Under an 

accidental spill scenario, workers may be exposed to triclopyr, imazapyr, and metsulfuronmethyl through dermal contact. However, the potential dermal contact exposure would be 

limited because these accidental events would be of low frequency and short duration.

In addition to worker exposure, there is the possibility of exposure to residents in areas after 

treatment. The general public is not expected to be exposed to the herbicides during the 

application process. Exposure of residents whose property has been treated can be 
minimized through proper notification prior to treatment. However, there is potential for the

general public to be exposed to herbicides shortly after application by walking through a 

treated area and sitting on treated stumps. Exposure to the general public to triclopyr 

residues was evaluated. Sensitive members of the population (i.e., adult females and pre-teen 

and teenaged children (age 11 to 16)) were used for the general public exposure assessment. 

Dermal contact with treated tree surfaces is the primary exposure route for the general public. 

Incidental ingestion and inhalation exposure routes are highly unlikely and were not 

evaluated. A dietary exposure route to the public is not expected because all of the 

herbicides will be used to only to treat tree stumps or sprouting vegetation. 

A significant exposure pathway is not idenified for groundwater or surface water in 

proximity of herbicide-treated stumps. Although triclopyr, imazapyr, and metsulfuronmethyl are all soluble, mobile, and can leach from soil to groundwater, the leaching potential 

is limited because the herbicides are applied directly to the tree stump or associated sprouting 

vegetation, which minimizes contact with the soil. Although surface runoff from treated 

stumps into aquatic resources is possible, the use pattern of spot treatment, current label 

restrictions, and low application rates limit the amount of these herbicides runoff to surface 

water. 

4.1.2 Exposure Evaluation

This section quantitatively evaluates worker exposure from direct contact while applying 

triclopyr using direct stump applications and backpack spraying, as well as to the general 

public from exposure resulting from direct contact with contaminated vegetation. The 

exposure scenarios evaluated for workers and the general public are related to short-term 

exposures because these herbicides are not persistent in the environment and probability of 

long-term exposure is low. 

Workers: The general worker exposure evaluated in this assessment is based on the two 

application methods, manual painting and backpack direct spray. For the manual painting 

application, the direct contact exposure scenario to a triclopyr solution is characterized by 

wearing triclopyr-contaminated gloves for 1 minute and 10 minutes. It is assumed that 

wearing gloves grossly contaminated with a chemical solution is equivalent to immersing the 

hands in the pesticide solution. Therefore, the chemical concentration in contact with the 

skin and the dermal absorption rate are essentially constant. Because the concentration of 

triclopyr in contact with the skin is nearly constant and the rate of absorption is constant, 

zero-order absorption (i.e., the dermal absorption rate is constant over time) kinetics is used. 

The rate of absorption under this exposure scenario is estimated based on central estimate 

(range) dermal permeability coefficients (Kp) of 1.3 x 10-4 (7.8 x 10-5 – 2.3 x 10-4) cm/hour 

for triclopyr TEA and 8.3 x 10-3 (4.4 x 10-3 – 1.6 x 10-2) cm/hour for triclopyr BEE (USDA 

FS, 2011c,d). 

For the backpack spray application, the direct contact exposure scenario estimate for a 

backpack worker to a triclopyr solution are characterized based on the amount of material 

handled per day. The worker exposure rate is 0.01 mg/kg bw per lb and ranges between 

0.001 mg/kg bw per lb and 0.08 mg/kg bw per lb. The worker exposure rates are the 

Appendix E. Herbicide Environmental Risk Assessment
geometric mean and 95% confidence intervals, based on a log-transformation of data from a

Forest Service assessment of worker exposure rates for triclopyr BEE (USDA FS, 2012).

For the spill/splash related dermal contact exposure scenario, exposure to a triclopyr solution 

is characterized by a spill on the lower legs as well as the hands, with a certain amount of the 

chemical adhering to the skin. The absorbed dose is calculated as the product of the amount 

of chemical on the surface of the skin (i.e., the amount of liquid per unit surface area 

multiplied by the surface area of the skin over which the spill occurs and the chemical 

concentration in the liquid), the first-order dermal absorption rate coefficient (Ka) (expressed 

as a proportion of the deposited dose absorbed per unit time—e.g., hour-1), and the duration 

of exposure. The rate of absorption under this exposure scenario is estimated based on the 

first-order dermal absorption rate coefficient (Ka) of 6.7 x 10-4 (2.4 x 10-4 – 1.8 x 10-3) hour-1

for triclopyr TEA and 2.6 x 10-3 (1.0 x 10-3 – 6.7 x 10-3) hour-1 for triclopyr BEE (USDA FS, 

2011c,d). Details regarding exposure assumptions are presented in Attachment A.

General Public: The exposure scenario developed for the general public assumes that an 

individual is exposed to the compound shortly after its application. The exposure scenario 

from contact with contaminated tree stumps assumes that the herbicide is sprayed at a given 

application rate, and that an adult female or a pre-teen and teenage child comes in contact 

with the sprayed tree stump surfaces on the same day. This exposure scenario depends on 

estimates of dislodgeable residue (the estimated amount of the chemical which could be 

released from vegetation, expressed in units of pesticide mass/surface area of vegetation), 

and dermal transfer rates (the rate at which the chemical is transferred from the contaminated 

vegetation to the surface of the skin). Dislodgeable residues are based on the pesticide, the 

formulation, and the site-specific conditions. Dermal transfer rates are reasonably consistent 

for a number of pesticides (Durkin et al.1995). This exposure assessment assumes a contact 

period of 10 minutes and that the chemical is not effectively removed by washing within 1 or 

2 hours of exposure. The assumptions regarding body weight, skin surface area, and firstorder dermal absorption rates are summarized in Attachment A.

4.2 Ecological Exposure Assessment

4.2.1 Aquatic Exposure Assessment

The three herbicides proposed for use in the ALB Eradication Program exhibit properties that 

suggest they could contaminate surface water. High solubilty and low soil adsorption 

coefficients increase the likelihood of off-site transport from runoff. Drift is not anticipated 

to be a significant pathway to aquatic environments from the proposed treatments. 

Herbicides are either hand painted onto stumps or backpack applications are made directly to 

the the stump and associated vegetation. The use of backpack sprayers, large coarse droplets 

during application, and other label requirements will result in negligible drift. Estimates of 

potential aquatic residues from runoff were evaluated for triclopyr BEE since it has a greater 

toxicity to aquatic vertebrates and invertebrates compared to triclopyr TEA, imazapyr, and 

metsulfuron-methyl. Aquatic residue values for this assessment were generated using the 

GLEAMS environmental fate model (USDA FS, 2003). The Forest Service determined the 

residues of triclopyr BEE in a small stream for three soil types and average annual rainfall 
amounts ranging from 5 to 250 inches per year. The application rate was1 lb a.e./acre with 

resulting residues ranging from zero to 0.149 mg/L. The highest concentrations were 

observed at the maximum average annual rainfall levels and in sandy soils which would be 

highly permeable and susceptible to runoff. The residues from these estimates were then 

compared to the available aquatic effects data for triclopyr BEE which is further discussed in 

the risk characterization section of this risk assessment.

4.2.2 Terrestrial Exposure Assessment

The potential for herbicide exposure to non-target terrestrial vertebrate wildlife is very low 

under the proposed uses. Treatments to stumps would not result in any appreciable exposure 

to non-target terrestrial vertebrates through either the oral, dermal, or inhalation pathways. In 

addition, the available toxicity data for birds and mammals through these exposure pathways 

demonstrates very low toxicity. There is the possibility that some mammals may graze on 

treated sprouting vegetation; however, there is no plausible exposure scenario resulting in 

adverse effects based on daily food consumption rates. There is the potential for exposure 

from drinking water. However, estimates for triclopyr BEE, discussed above, are very low 

and any non-target vertebrate wildlife would have to consume several times their daily water 

intake to receive a dose that would approach an adverse effect.

5.0 RISK CHARACTERIZATION

5.1 Human Health 

Risks associated with adverse human health effects are characterized quantitatively in this 

section. The potential adverse health effects to subgroups within the population from exposure 

to triclopyr were evaluated using a hazard quotient (HQ) approach. A HQ is the ratio of the 

estimated level of total exposure to the relevant noncancer toxicity criterion (i.e., appropriate 

RfD) for a specific exposure pathway (or for a single substance). If there is more than one 

chemical, the HQs are summed over all exposure pathways and all chemicals to develop a total

hazard index (HI). If the HI is less than 1, it is considered unlikely that the exposure will cause 

adverse health effects; conversely, if the HI is greater than 1, then health effects may result from 

exposure. Unlike cancer risk estimates that are expressed as probabilities (e.g., 1 in a million), 

HIs are deterministic methods of estimating risk and do not represent the probability of health 

effects, but are presented to provide context to the relationship between the known toxicity of a 

substance and the estimated magnitude of exposure. The risk estimations associated with the 

triclopyr exposure scenario are expected to be representative of the mixed herbicide 

scenario. This is because triclopyr has at least an order of magnitude higher toxicity compared to 

the other two herbicides (RfD of 0.05 mg/kg/day for triclopyr, RfDs of 2.5 mg/kg/day for 

imazapyr, and 0.25 mg/kg/day for metsulfuron-methyl). Adding HQs from the other two 

compounds is not expected to raise the total HI to exceed the USEPA level of concern (HI of 

1).

Workers: The HQs for general and accidental exposures of workers are calculated and 

summarized in table 5-1. The HQs are based on the total exposure that a worker might receive 

during a directed foliar application at a label allowable maximum application rate of 9 lb/acre 

Appendix E. Herbicide Environmental Risk Assessment
(TEA) and 8 lb/acre (BEE) with the acute RfD of 1 mg/kg/day. The use of the acute RfD for risk 

characterization for the general worker exposure (male workers) is intended only to illustrate the 

consequences of applying triclopyr sporadically as part of other activities. The HI values for the 

three worker-exposure scenarios (i.e., manual painting application direct contact, backpack spray 

application direct contact, and spill/splashing-related dermal contact) are less than or do not 

exceed the USEPA level of concern of 1 under the central and lower estimations for both 

triclopyr TEA and triclopyr BEE. The upper estimate HQ of 7 for triclopyr BEE under the 

contaminated gloves with 10 minutes exposure scenario and the upper estimate HQs of 6 for 

triclopyr TEA and 5 for triclopry BEE under the backpack application exposure scenario 

exceeded the level of concern. However, these risk estimations are conservative values based on 

the maximum labelled application rates (9 lb a.e./acre TEA and 8 lb a.e./acre BEE) instead of a 

typical application rate (1 lb a.e./acre). The hazard quotients calculated for a typical application 

rate are less than one (table 5-2). The backpack application exposure scenario also 

conservatively assumes no protective clothes resulting in overestimation of risk, which will be 

minimized by the proper use of PPE. The central risk estimates are a more typical exposure 

scenario. Therefore, it is unlikely that the exposure to workers will cause adverse health effects. 

Table 5-1. Hazard quotient values estimated for workers making triclopyr applications at 

maximum rates.

Exposure Scenario

Hazard Quotient

Form Central 

Estimate

Lower 

Estimate

Upper Estimate

Accidental/Incidental Exposure

Contaminated Gloves, 1 min. TEA 2 x 10-3 5 x 10-4 1 x 10-2

BEE 7 x 10-2 2 x 10-2 7 x 10-1

Contaminated Gloves, 10 mins TEA 1 x 10-2 5 x 10-3 1 x 10-1

BEE 7 x 10-1 2 x 10-1 7

Spill on Hands, 1 hour TEA 3 x 10-3 7 x10-4 4 x10-2

BEE 1 x 10-2 3 x10-3 1 x10-1

Spill on lower legs, 1 hour TEA 7 x 10-3 1 x10-3 9 x10-2

BEE 2 x 10-2 6 x10-3 3 x10-1

General Exposures

Backpack Applications TEA 4 x 10-1 1 x10-3 6

BEE 4 x 10-1 1 x10-3 5

HI TEA 0.4 0.008 6

BEE 1 0.2 12

Bold and shaded - Hazard quotient/index exceeding the target hazard quotient/index of 1.

Note: HI is the sum of HQs of the contaminated gloves (10 minutes), spill on hands, spill on lower legs, and 

backpack applications exposure scenarios. 
Table 5-2. Hazard quotient values estimated for workers making triclopyr applications at 

typical application rate.

Exposure Scenario

Hazard Quotient

Form Central 

Estimate

Lower 

Estimate

Upper Estimate

Accidental/Incidental Exposure

Contaminated Gloves, 1 min. TEA 2 x 10-3 5 x 10-5 1 x 10-3

BEE 9 x 10-3 3 x 10-3 8 x 10-2

Contaminated Gloves, 10 mins TEA 1 x 10-3 5 x 10-4 1 x 10-2

BEE 9 x 10-2 3 x 10-2 8 x 10-1

Spill on Hands, 1 hour TEA 3 x 10-4 8 x10-5 5 x10-3

BEE 1 x 10-3 3 x10-4 2 x10-2

Spill on lower legs, 1 hour TEA 7 x 10-4 2 x10-4 1 x10-2

BEE 3 x 10-3 7 x10-4 4 x10-2

General Exposures

Backpack Applications TEA 4 x 10-2 2 x10-4 6 x 10-1

BEE 4 x 10-2 2 x10-4 6 x 10-1

General Public: The HQs for potential herbicide exposure to the general public are calculated 

and summarized in table 5-3. The HQs are based on the exposure scenario where an adult 

female or a pre-teen and teenaged child (age 11-16) could be exposed to dislodgeable residues 

shortly after a foliar application at the label allowable maximum application rates of 9 lb/acre 

(TEA and TCP) or 8 lb/acre (BEE), for a direct contact time of 10 minutes and exposure duration 

for 1 hour (adult female) and 2 hour (pre-teen and teenaged child). The chronic RfDs of 0.05 

mg/kg/day (TEA and BEE) and 0.012 mg/kg/day (TCP) were used for the adult female as a 

conservative approach. The HIs for the adult female and pre-teen and teenaged child are all less 

than USEPA level of concern of one suggesting that it is unlikely that herbicide exposure to the 

general public will cause adverse health effects.

Table 5-3. Hazard quotient values estimated for general public after triclopyr applications.

Exposure Scenario

Hazard Quotient

Form Central 

Estimate

Lower 

Estimate

Upper Estimate

Non-accidental Acute Exposure

Vegetation contact, shorts and T-shirt – an adult female

TEA 3 x 10-3 1 x 10-3 8 x 10-3

BEE 1 x 10-2 4 x 10-3 2 x 10-2

TCP 2 x 10-1 7 x 10-2 6 x 10-1

HI 0.2 0.08 0.6

Vegetation contact, shorts and T-shirt – a pre-teen and teenaged child (11-16)

TEA 3 x 10-4 1 x10-4 8 x10-3

Appendix E. Herbicide Environmental Risk Assessment
BEE 1 x 10-3 4 x10-4 3 x10-3

TCP 2 x 10-1 8 x10-2 6 x10-1

HI 0.2 0.08 0.6

Under the proposed use patterns, triclopyr, and triclopyr mixed with imazapyr and 

metsulfuron-methyl should pose minimal risks to human health.

5.2 Aquatic and Terrestrial Ecological Risk Characterization

This section of the risk assessment will integrate the effects analysis regarding toxicity studies 

summarized for terrestrial and aquatic nontarget organisms with the potential for exposure to 

quantify whether direct or indirect risks would be anticipated for nontarget organisms and 

domestic animals from program use of triclopyr, imazapyr, and metsulfuron-methyl. Direct risk 

refers to those risks that could occur from direct exposure to the herbicides while indirect risks 

refer to impacts that could occur to prey or habitat that nontarget organisms rely on for food and 

shelter. In cases where the range of response data to each herbicide does not fall within the 

range of potential exposure values, impacts to individuals and populations are not anticipated. 

Further evaluation of the assumptions used in the risk characterization is required to refine risk 

where residues exceed the response data.

5.2.1 Aquatic

The available aquatic toxicity data for vertebrates and invertebrates for all three herbicides 

suggests that these taxa would be at very low risk from herbicide applications. Triclopyr 

BEE poses the greatest risk to aquatic vertebrates and invertebrates based on its toxicity 

profile while imazapyr and metsulfuron-methyl pose the least amount of risk because both 

products would be considered practically non-toxic to aquatic invertebrates and vertebrates. 

Based on the low frequency of use in the ALB program and the method of application, there 

is a low likelihood that any associated drift and runoff from these applications would result in 

significant risk to aquatic vertebrates or invertebrates. The risk to aquatic plants is greater 

based on the known toxicity for each herbicide. Effects to aquatic plants can result in 

indirect effects to aquatic vertebrates and invertebrates that rely on these species for food and 

shelter. The proposed use pattern would minimize the potential for significant residues from 

drift or runoff to aquatic habitats. In addition, current label requirements restricting 

applications in aquatic areas would further reduce the potential for residues. 

The acute aquatic risk from the use of triclopyr BEE was determined for aquatic vertebrates, 

invertebrates and plants based on a typical application rate (1 lb a.e./acre) and the maximum 

labelled used rate (8 lb a.e./acre) (figure 5-1). 
Figure 5-1. Aquatic risk characterization for triclopyr BEE.

Residue values were compared to the range of acute aquatic toxicity data. A presumption of 

risk occurs when there is an overlap between residues and the range of acute toxicity data. 

This was done for triclopyr BEE due to its ten fold or greater toxicity when compared to 

triclopyr TEA, imazapyr, and metsulfuron-methyl. The waterbody that was modeled in this 

exercise was a small stream (USDA FS, 2003). Residues were estimated using the GLEAMS 

environmental fate model for three soil types (clay, loam, and sand) and annual yearly 

rainfall amounts ranging from 5 to 250 inches. Chronic risk comparisons were not made 

because triclopyr BEE degrades rapidly in water to triclopyr acid, and chronic exposure to 

the ester would not occur. The residues estimated from this excerise are conservative 

estimates because they assume applications occur to soil, which would not be the case for 

proposed stump applications. There is the possibility of some triclopyr BEE moving to soil 

due to a rainfall event, but applications will be made to minimize the potential for runoff. 

Residues at 1 and 8 lb a.e./acre exceed the distribution of toxicity data for aquatic plants and 

exceed the effects distribution for aquatic vertebrates at the maximum labelled rate. Residues 

were below all toxicity values in all soil types when considering areas that had 100 inches or 

less of annual rainfall. Areas in the United States with annual average rainfall amounts 

greater than 100 inches are restricted to coastal areas in the Pacific Northwest and a small 

portion of northwest California. These are not considered high risk areas for the introduction 

of ALB, thus, the aquatic risk from triclopyr BEE for stump treatments is very low for a 

majority of the country based on conservative estimates of exposure. Due to the significant 

reduction in toxicity for triclopyr TEA, imazapyr, and metsulfuron-methyl the potential for 

aquatic risk would be much less for these three herbicides when compared to triclopyr BEE. 

5.2.2 Terrestrial Wildlife and Domestic Animals

The risk to non-target terrestrial vertebrate wildlife and domestic animals will be negligible 

based on the proposed method of application for each herbicide and available toxicity data 

for mammals and birds. Direct application of herbicides to stumps and sprouting vegetation 

0.0001 0.001 0.01 0.1 1 10 100

Log Triclopyr BEE Concentrations (mg/L) 

Estimated Acute Residues (1 lb ae/ac) 

Acute Fish and Amphibian Effects 

Acute Invertebrate Effects 

Acute Aquatic Plants Effects 

Estimated Acute Residues (8 lb ae/ac) 

Appendix E. Herbicide Environmental Risk Assessment
using hand painting or hand held sprayers reduces the likelihood of off-site drift and runoff. 

Any plausible scenarios where mammals and birds would be exposed to significant residues 

on stumps or associated sprouting vegetation is unlikely. Some mammals, such as whitetailed deer, may graze on sprouts from stumps that have been selectively treated with 

herbicides. However, the toxicity profiles for all three herbicides suggest mammals would 

have to consume many times their daily food consumption rates over an extended period of 

time to reach a dose that could result in any acute or chronic effects. Treated vegetation 

would become unpalatable as the sprout dies back due to herbicide treatment, reducing 

exposure time. Incidental soil ingestion by foraging mammals and birds would also be low 

because applications are directed to the stump and sprouting vegetation using hand held 

sprayers. Risk from herbicide exposure through drinking water to nontarget vertebrates 

would also be very low based on aquatic residues estimated in a small stream using 

applications of triclopyr BEE. Non-target vertebrate wildlife and domestic animals would 

have to consume many times their daily water ingestion rate to consume a dose that could 

result in an adverse effect. There is no plausible exposure scenario where that situation could 

occur. Risks from ingestion of drinking water containing triclopyr TEA, TCP, imazapyr, and 

metsulfuron-methyl would be even less due to their comparative lower toxicity, and in the 

case of imazapyr and metsulfuron-methyl, much lower use rates compared to triclopyr.

5.2.3 Terrestrial Invertebrates and Plants

Herbicide applications are not expected to result in adverse impacts to terrestrial 

invertebrates. Available toxicity data for terrestrial invertebrates shows that toxicity is low 

for pollinators, such as honey bees, as well as soil borne invertebrate species for all three 

herbicides. The greatest potential for exposure would be for soil borne invertebrates 

however, the method of application suggests that any significant residues would be 

immediately adjacent to any treated stumps. 

All three herbicides are toxic to terrestrial plants, and non-target plants immediately adjacent 

to the treatment site would be at risk from drift and runoff. The method of application will 

reduce the risk to terrestrial plants because applications are made by hand directly to stumps 

and any associated sprouting vegetation which would minimize and drift and runoff. 

6.0 UNCERTAINTIES AND CUMULATIVE IMPACTS

The uncertainties associated with this risk evaluation arise primarily from a lack of information 

about the effects of each herbicide, its formulations, metabolites, and potential mixtures to nontarget organisms that can occur in the environment. These uncertainties are not unique to this 

assessment but are consistent with uncertainties in human health and ecological risk assessments 

with any environmental stressor. In addition, there is uncertainty in where an ALB infestation 

may occur in the United States and the extent of herbicide use in a given area because 

application is based on site-specific factors. As a way to account for some of the uncertainty 

with the available data APHIS made conservative assumptions regarding exposure and relied on 

the more sensitive effect endpoints to assess risk to human health and the environment. 
Another area of uncertainty is the potential for cumulative impacts to human health and the 

environment from the proposed use of the three herbicides together and how they may interact 

with other biotic and abiotic stressors. Areas where cumulative impacts could occur are: 1) 

repeated worker and environmental exposures to each herbicide in relation to other uses; 2) coexposure to other chemicals with a similar mode of action; and 3) exposures to other chemicals 

in mixtures and how that may affect the toxicity of each herbicide.

From a human health perspective, the ALB program use of triclopyr and the tank mix of the 

three herbicides are expected to result in negligible cumulative impacts when considering the 

proposed use patterns. The herbicides are not expected to enter the food chain through food and 

drinking water and significantly add to triclopyr, imazapyr, and melsulfuron-methyl exposures 

and other stressors in the human population. 

Cumulative impacts may occur from the use of each herbicide as well as the three herbicides 

together in relation to other chemicals that have a similar mode of action, as well as others that 

have a different mode of action, but could result in synergistic, additive, or antagonistic effects. 

The cumulative impacts from the individual use of triclopyr or the three herbicides together are 

expected to be low because they are not persistent in the environment or bioaccumulative (Tatum 

2004). In addition, their selective use in the ALB Eradication Program and the methods of 

application reduce exposure. The low probability of exposure and favorable toxicity profile 

result in very low risk to human health and to most non-target wildlife so that any cumulative 

impacts from the use of herbicides relative to other stressors would be incrementally negligible. 

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Attachment A: Risk Estimations for Workers and General Public

USDA Forest Service Program Worksheets for triclopyr TEA and triclopyr BEE formulations for 

terrestrial applications (worksheet version: 5.00.64) and TCP from terrestrial applications of 

triclopyr (version 6.00.01) (USDA FS, 2011c,d,e) were used for the risk estimations. 

Attachment A summarizes the exposure concentrations, exposure assumptions and toxicity 

values used in the hazard quotient estimates to workers and the general public. 

Attachment A-1 Concentrations in field solutions and exposure rates.

Parameter/Assumption Range Value Units Reference

Application rate 9 / 8 Lb/acre The maximum rate 

per label (9 lb/acre 

for TEA and TCP 

per Garlon 3A label 

& 8lb/acre per 

Pathfinder II label)

Application Volume Central 25 Gal/acre USDA FS, 2011a

Upper 40

Lower 5

Concentration in field solution Central 0.36/0.32 Lb/gal Calculated

Upper 0.225/0.2

Lower 1.8/1.6

Conversion factor for lbs/gal to 

mg/ml

119.8 mg/mL per 

lb/gal

Concentration in field solution Central 4.30E+01/3.80E+01 mg/mL Calculated

Lower 2.70E+01/2.40E+01

Upper 2.20E+02/1.90E+02

Number of Applications 1 Unitless USDA FS 2011a

Application Interval 1 Days USDA FS 2011a

Worker Exposure Rate Central 0.01 mg/kg bw USDA FS 2012

Lower 0.0001 per lb

Upper 0.08

Number of acres that the worker 

will treat per hour Central 0.625 Acres/hr

Lower 0.25 USDA FS 2012

Upper 1

Number of hours of worker 

exposure per day. Central 7

Lower 6 USDA FS 2012

Upper 8

Appendix E. Herbicide Environmental Risk Assessment
Attachment A-2 Exposure assumptions for herbicide risk estimations

Receptors Factor Value Units Reference

Backpack Worker Absorbed dose rate USDA FS 2012

Central 0.01 (mg/kg bw)/(lbs

Upper 0.0001 handled per day)

Lower 0.08

Hours of application per day

Central 7 Hours per day USDA FS 1989

Upper 6

Lower 8

Acres treated per hour

Central 0.625 acres/hour USDA FS 1989

Lower 0.25

Upper 1

Adult Male 

Worker

Body weight 80 kg USEPA 2011

Surface Area, Hands 1070 cm2 USEPA 2011

Surface Area, Lower legs 2273 cm2 USEPA 2011

Exposure duration 1/10/60 minutes Contaminated 

gloves and spill, 

professional 

judgment 

Adult Female Body weight 71 kg USEPA 2011

Surface Area, Wearing shorts 

and T-shirt

Contact time/Exposure 

Duration

6473

10 /1 

cm2

minutes/hour

USEPA 2011

Professional 

Judgment

Pre-teen and 

teenaged Child 

(11-16)

Body weight 56.8 kg USEPA 2011

Surface Area, Wearing shorts 

and T-shirt 

Contact time/Exposure 

Duration

5650

10 / 2

cm2

minutes/hour

USEPA 2011

Professional 

Judgment

Attachment A-3 Conversion factors for herbicide risk estimations.

Receptors Factor Value Units Reference

Conversion 

Factors

acrefoot2gal 325900 gal/acre-foot Budavari 1989

liters per gal 3.785 L/gal Budavari 1989

pound per milligram 453600 mg/lb Budavari 1989

lbac2

mgcm2 0.01121 mg/cm2 per lb/acre Budavari 1989

lbac2

ugcm2 11.21 ug/cm2 per lb/acre Budavari 1989

conversion for milligrams to pounds 2.204E-06 lb/mg Budavari 1989 

conversion for milliliters to gallons 3785 ml/gal Budavari 1989

Misc Liquid adhering to skin 0.008 mL/cm2 Mason and Johnson 

1987

Dislodgeable residue as proportion 0.1 none Harris and Solomon 

1992
Attachment A-4 Summary of toxicity values

Compound Duration Toxicity Value 

(RfD – mg/kg/day)

Reference

Triclopyr TEA Acute 1

USDA FS, 2011a, USEPA 2002a

Chronic 0.05

Triclopyr BEE Acute 1

Chronic 0.05

TCP Acute 0.025

Chronic 0.012

Appendix E. Herbicide Environmental Risk Assessment

Appendix F. Imidacloprid Human Health and 

Ecological Risk Assessment: Asian 

Longhorned Beetle Eradication Program

Appendix F. Imidacloprid Environmental Risk Assessment
Table of Contents

EXECUTIVE SUMMARY

1.0 INTRODUCTION

2.0 PROBLEM FORMULATION

2.1 Chemical Description and Product Use

2.2 Physical and Chemical Properties

2.3 Environmental Fate

2.4 Hazard Identification

2.4.1 Acute Toxicity

2.4.2 Sub-Chronic/Chronic Toxicity

2.4.3 Carcinogenicity/Mutagenicity

2.4.4 Development and Reproductive Effects

2.4.5 Endocrine Effects

2.4.6 Immune System Effects

2.4.7 Metabolism

3.0 DOSE-RESPONSE ASSESSMENT

3.1 Human Health Dose-Response Assessment

3.2 Ecological Effects Analysis

3.2.1 Aquatic Effects Analysis

3.2.2 Terrestrial Effects Analysis

3.2.3 Toxicity of formulations and metabolites to nontarget wildlife

4.0 EXPOSURE ASSESSMENT

4.1 Human Health Exposure Assessment

4.1.1 Identification of Potentially Exposed Human Populations and Complete 

Exposure Pathways

4.1.2 Exposure Evaluation

4.2 Ecological Exposure Assessment

4.2.1 Aquatic Exposure Assessment

4.2.2 Terrestrial Exposure Assessment

5.0 RISK CHARACTERIZATION

5.1 Human Health

5.2 Aquatic and Terrestrial Ecological Risk Characterization

5.2.1 Aquatic

5.2.2 Terrestrial Wildlife and Domestic Animals

5.2.3 Terrestrial Invertebrates and Plants

6.0 UNCERTAINTIES AND CUMULATIVE IMPACTS

7.0 REFERENCES
EXECUTIVE SUMMARY

The United States Department of Agriculture (USDA), Animal and Plant Health Inspection 

Service (APHIS) proposes to use the insecticide imidacloprid as part of an eradication program 

for the Asian Longhorned Beetle (ALB).

USDA APHIS evaluated the potential human health and ecological risks from the proposed use 

of imidacloprid for the ALB eradication program. Risks to human health are expected to be 

negligible based on limited exposure from the proposed use pattern of imidacloprid (trunk and 

soil injection). Exposure is greatest for workers who will apply the product, but the formulation 

and the required protective equipment result in a low potential for exposure and risk. 

Ecological risks for terrestrial and aquatic non-target organisms is also expected to be low based 

on the toxicity and environmental fate of imidacloprid, and method of application. Risks to 

terrestrial invertebrates, including pollinators, is expected to be negligible based on available 

laboratory data and field collected data for pollinators that has been collected for ALB specific 

applications of imidacloprid. There is some risk to sensitive terrestrial invertebrates that consume 

vegetation from treated trees or inhabit the soil where soil injection is used.

1.0 INTRODUCTION

This human health risk assessment (HHRA) and ecological risk assessment (ERA) provide a

quantitative and qualitative evaluation of the potential risks and hazards to human health,

nontarget fish, and wildlife as a result of exposure to the insecticide, imidacloprid, when used for 

controlling the ALB.

The methods used in this HHRA to assess potential human health effects follow standard 

regulatory guidance and methodologies (NRC, 1983; USEPA, 2014a), and generally conform to 

other Federal agencies such as U.S. Environmental Protection Agency (USEPA), Office of 

Pesticide Programs (USEPA/OPP). The methods used in this ERA to assess potential ecological 

risk to nontarget fish and wildlife follow USEPA methodologies regarding eco-risk assessment, 

with an emphasis on those used by USEPA/OPP in the pesticide registration process. 

The risk assessment starts with problem formulation (identifying hazard), then the toxicity 

assessment (the dose-response assessment), and then the exposure assessment (identifying 

potentially exposed populations and determining potential exposure pathways for these 

populations). Lastly, the information from the exposure and toxicity assessments is combined to 

characterize risk (determining whether there is adverse health and eco-risk). 

2.0 PROBLEM FORMULATION

APHIS is proposing the use of the insecticide imidacloprid to treat high risk host trees that are 

not cut to prevent further spread of ALB as part of the ALB eradication. The following sections 

discuss the chemical description and product use; physical and chemical properties; 

environmental fate; and hazard identification for imidacloprid. 

Appendix F. Imidacloprid Environmental Risk Assessment
2.1 Chemical Description and Product Use

Imidacloprid (C9-H10-Cl-N5-O2) (CAS No. 138261-41-3) belongs to a class of insecticides, 

neonicotinoids, that act by binding directly to the acetylcholine binding receptor. The molecular 

structure is shown in Figure 1. Imidacloprid is manufactured in several different formulations 

that can be used for soil, seed and foliar applications. It is registered for use on a wide variety of 

agricultural commodities as well as in horticultural and turf applications and for animal health.

Imidacloprid controls a variety of insects including sucking insects such as psyllids, aphids, 

thrips, whiteflies, rice hoppers, turf and soil insects, and some beetles. In the ALB eradication 

program, an imidacloprid formulation such as Merit® 2F will be applied through trunk or soil 

injection at the base of the tree. After application, imidacloprid is taken up and distributed 

throughout the tree (USDA APHIS, 2013). Merit® 2F (21.4% imidacloprid as an active 

ingredient and 78.6% others as inerts) contains 2 pounds of imidacloprid per gallon (Bayer 

2004).

Figure 1 - Molecular Structure (a chloronicotinyl nitroguanidine insecticide)

2.2 Physical and Chemical Properties 

Imidacloprid is a colorless crystal with a slight odor. Its melting point is 144o

C. It is not 

considered volatile due to a low vapor pressure (3 x 10-12 mmHg at 20oC). The partition 

coefficient (log Kow) is 0.57 at 21 oC suggesting it would not bioaccumulate in lipids. The

solubility in water is 0.61 grams per liter (g/L) at 20°C. The estimated Henry’s constant value is 

2 x 10-15 atm-m3

/mole at 20oC. 

2.3 Environmental Fate

The environmental fate describes the processes by which imidacloprid moves and transforms in 

the environment. The environmental fate processes include: 1) mobility, persistence, and 

degradation in soil, 2) movement to air, 3) migration potential to groundwater and surface water, 

and 4) plant uptake. 

In soil, imidacloprid soil organic carbon-water partitioning coefficient (Koc)1 values range from 

157 to 810 in various soil types and organic carbon levels suggesting that in most cases 

imidacloprid does not adsorb strongly to soil particles (USDA FS, 2005; HSDB 2014). The

adsorption capacity of imidacloprid to soil is correlated with the amount of soil organic matter 

(Liu et al., 2006). Imidacloprid is less mobile in organic carbon and clay soils and more mobile 

in sand and gravel soils (HSDB, 2014). The leaching potential also depends on the soil type and 

organic content level in soil. Several studies have shown that imidacloprid does not leach to 

1 KOC values are useful in predicting the mobility of organic soil contaminants. Higher KOC values correlate to less 

mobile organic chemicals while lower KOC values correlate to more mobile organic chemicals.
ground water in silty loam and silt soils with high organic matter content.(Miles, Inc., 1992; 

Rouchaud et al., 1994). A leaching study in fine sandy loam soil demonstrated the potential for 

imidacloprid residues to move downward through the soil with percolating water (Felsot et al., 

1998).

Soil photolysis half-lives range from 19 to 39 days (CA DPR, 2006a; Graebing and Chib, 2004). 

Aerobic soil metabolism half-lives show imidacloprid to be persistent with half-lives ranging 

from 83 days to greater than one year (CCME, 2007). Imidacloprid degrades more rapidly in 

soil under aerobic conditions with vegetation (half-lives of 48 days) compared to soil without 

vegetation (half-lives of 190 days) (HSDB, 2014). Imidacloprid degrades under anaerobic 

aquatic conditions more rapidly than under aerobic soil conditions (HSDB, 2014). At the soil 

surface, imidacloprid has a photolysis half-life of 39 days. When incorporated into soil, the 

photolysis dissipation half-life of imidacloprid varies from 27 to 229 days (CA DPR, 2006a).

The half-lives tend to increase with increasing pH values but decrease in the presence of light 

(Sarkar et al., 2001; CA DPR, 2006a).. Soil half-life values in the absence of light are as high as 

229 days in field studies and 997 days under laboratory conditions (CA DPR, 2006a). Several 

field dissipation studies have been conducted with imidacloprid under various crop, soil, and 

weather conditions with a resulting half-life range of 7 to 107 days (USDA FS, 2005). 

Imidacloprid degrades under anaerobic aquatic conditions more rapidly than under aerobic soil

conditions (HSDB, 2014).

In air, imidacloprid is expected to exist solely in the particulate phase and not expected to 

volatilize into the ambient atmosphere based on the low reported volatility (3 x 10-12 mm Hg) 

and Henry’s Law Constant2 (2 x 10-15 atm m3

/mole) (HSDB, 2014). 

Imidacloprid is considered soluble in water with values ranging from 510 to 610 mg/L (USDA

FS, 2005). In aquatic environments imidacloprid is resistant to hydrolysis at all relevant pH 

values but is susceptible to aquaeous photolysis with half-lives of less than 5 hours (USDA FS, 

2005). 

In plants, imidacloprid applied through trunk or soil injection to host trees will translocate 

throughout the tree. These applicaton methods were used previously in the ALB eradication 

programs in New York and Illinois. During the environmental monitoring, paired leaf and twig 

samples from eight different species of host trees in New York were collected periodically for 15 

months to test for the presence of imidacloprid residues. Tree species included Norway, 

sycamore, sugar and silver maple, poplar, elm, hackberry and mountain ash. Plant tissue 

sampling of trees treated with imidacloprid using the same application methods indicated that 

both leaves and twigs have detectable residues of imidacloprid concentrations (USDA APHIS, 

2002). The detected concentrations in leaves were higher than the detected concentrations in 

twigs. Imidacloprid appears to be distributed predominately in areas that are rapidly growing 

(i.e., leaves) based on the sampling data. The sampling data also shows that uptake and 

distribution varied by tree species. Blossom sampling results (USDA APHIS, 2001; 2002) show 

that imidacloprid residues were either not detected or detected at low levels not quantifiable 

2 Henry’s law constant is the ratio of a chemical’s concentration in the air to its concentration in water at 

equilibrium. 

Appendix F. Imidacloprid Environmental Risk Assessment
(0.03 to 0.099 ppm) except for one blossom sample that contained 0.13 ppm (USDA APHIS, 

2002). 

The half-life of imidacloprid on vegetation from field dissipation studies has been shown to 

range from 1.17 days in potatoes to 9.8 days on turf. Because applications in this program are 

not foliar, this route of degradation is not expected to be significant since imidacloprid will be 

translocated by plant roots into the tree or distributed throughout the tree from trunk injection 

sites by the tree’s vascular system. The main breakdown products of imidacloprid in plants 

includes a monohydroxy metabolite, imidacloprid guanidine, imidacloprid olefin, and a

monoglucoside of 6-chloropicolyl alcohol (CA DPR, 2006a).

2.4 Hazard Identification 

Imidacloprid, a neonicotinoid insecticide, results in toxicity through binding or partial binding to 

specific areas of the nicotinic acetylcholine receptor (nAChR). Acetylcholine is an important 

neurotransmitter in most animals. It is released at the nerve synapse in response to a membrane 

depolarization that is the initiator of nerve transmission. Acting as an inhibitor at nicotinic 

acetylcholine receptors, imidacloprid disrupts the nervous system. Imidacloprid is more toxic to 

insects than to mammals because it has higher binding strength to the nicotinic receptors of 

insect nerve cells than to mammalian receptors (Tomizawa and Casida, 2003; Gervais et al.,

2010). 

Imidacloprid has moderate acute oral toxicity and low acute dermal and inhalation toxicity, but is 

not an eye or dermal irritant, or dermal sensitizer. The primary target of imidacloprid is the 

nervous system. Imidacloprid has been shown to have thyroid and/or liver effects in chronic 

dietary studies in rats and dogs. These reported impacts occurred at levels above those 

anticipated from imidacloprid use in the ALB eradication program. Reports of imidacloprid 

deliberate self-poisoning or accidental exposure in humans have shown low lethality (Mohamed 

et al., 2009; Gervais et al., 2010; Lin, et al., 2013; Kumar et al., 2013). Signs of toxicity include 

drowsiness, dizziness, vomiting, disorientation, and fever (Gervais et al., 2010). Other more 

serious health effects from exposure to imidacloprid include compromised respiratory, 

cardiovascular, and neurological function such as dyspnoea/apnoea, coma, tachycardia, 

hypotension, mydriasis, and bradycardia (Lin et al., 2013). Kumar et al. (2013) reported signs of 

acute inhalation intoxication from an accidental imidacloprid exposure that included severe 

gastrointestinal symptoms, respiratory distress, and neuropsychiatric features. Signs of toxicity 

from accidental inhalation of a pesticide containing 17.8% imidacloprid included becoming 

disoriented, agitated, incoherent, with sweating and breathlessness (Gervais et al., 2010). Two 

fatal incidents of deliberate ingestion were associated with suicides (Gervais et al., 2010; 

Iyyadurai et al., 2010).

2.4.1 Acute Toxicity

Multiple acute toxicity studies have been conducted using imidacloprid on several 

mammalian species. These studies along with other available data have been summarized in 

several reports (CA DPR, 2006b; USDA FS, 2005; USEPA, 2005; USEPA, 2010). Acute 

oral median lethal toxicity values range from 131 mg/kg for the mouse to 475 mg/kg for the 

rat, suggesting moderate acute toxicity to mammals. Inhalation and dermal toxicity is 
considered low for imidacloprid with LC50 and LD50 values greater than 5.33 mg/L and 

2,000 mg/kg, respectively. Acute oral and inhalation sublethal effects have been measured in 

the rat and mouse with oral no observable effect levels (NOEL) ranging from 10 to 50 

mg/kg/day and inhalation NOELs ranging from 3.4 to 192 mg/kg/day (CA DPR, 2006b). 

Sublethal impacts noted in these studies were apathy, labored breathing, trembling and 

staggering gait. An acute neurotoxicity study in rats reported a lowest observable adverse 

effect level (LOAEL) of 42 mg/kg (USEPA, 2010). The California Department of Pesticide 

Regulations (CA DPR) has used this value to set the acute benchmark dose (BMD0.5) of 9 

mg/kg/day while USEPA determined that the reported NOEL was a LOEL and calculated an 

acute Population-Adjusted Dose (aPAD)/Reference Dose (RfD) of 0.14 mg/kg/day based on 

the application of uncertainty factors (CA DPR, 2006b; USEPA, 2010). An uncertainty 

factor of 300 (10X for interspecies extrapolation, 10X for intraspecies variation, and 3X for 

the use of a LOAEL due to the lack of a NOAEL) was applied to the aPAD (USEPA, 2010). 

The acute oral LD50 values obtained from rat studies for one of the available imidacloprid 

formulations, Merit® 2F, demonstrates lower acute toxicity when compared to the technical 

active ingredient (table 2-1). The acute inhalation toxicities are very low (LC50 > 2.0 mg/L)

for both the technical imidacloprid and the Merit® 2F formulation.

Table 2-1. Comparative acute mammalian toxicity between the technical active ingredient 

and the formulated imidacloprid . 

* Source: USDA FS, 2005; Bayer, 2008

2.4.2 Sub-Chronic/Chronic Toxicity

Chronic toxicity is a condition caused by repeated or long-term exposure to low doses of a 

toxic substance. Several sub-chronic studies have been submitted to support the registration 

of imidacloprid. Studies range in duration from 21 to 107 days testing under oral, dermal,

and inhalation exposures (CA DPR, 2006b; USDA FS, 2005) (table 2-2).

Toxicity Study Technical Imidacloprid Merit® 2F*

Acute Oral LD50 (rat) 424 mg/kg (M)/450 mg/kg (F) >4,870 mg/kg (M)/4,143 

mg/kg (F)

Acute Dermal LD50 >5,000 mg/kg (rat) > 2,000 mg/kg (rabbit)

Acute Inhalation LC50 (rat) >5.3 mg/L >5.33 mg/L

Dermal Irritation (rabbit) No irritation No irritation

Ocular (rabbit) No irritation Mild Irritation (Minimally 

irritating)

Sensitization (Guinea pig) Non-sensitizing Non-sensitizing

M= male; F=Female 

Appendix F. Imidacloprid Environmental Risk Assessment
Table 2-2. Subchronic mammalian effects studies using imidacloprid.

Test Animal Exposure/Duration NOEL 

(mg/kg/day)

LOEL (mg/kg/day)

Rat Oral/98 days 14.0 61.0

Rat Inhalation/28 days 0.9 5.2

Rat Oral Neurtoxicity/91 days 9.3* NR

Mouse Oral/107 days 86.0 427.0

Dog Oral/28 days 7.3 31.0

Dog Oral/91 days 8.0 24.0

Rabbit Dermal/21 days >1,000 >1,000

*Value represents the lowest reported NOEL from the study; NR = Not Reported

Chronic studies have been conducted using the rat, dog and mouse in oral exposures ranging 

from one to two years. The rat was the most sensitive test species with a NOEL and LOEL 

of 5.7 and 17 mg/kg/day, respectively. Comparative values for the dog and mouse were 

higher with NOELs of 15 and 47, respectively, and LOELs of 41 and 143 mg/kg/day (CA 

DPR, 2006b). The NOEL reported in the two year rat study was used by USEPA/OPP to set 

the chronic reference dose (RfD) of 0.057 mg/kd/day (USEPA, 2010). RfD is “an estimate 

of daily oral exposure to the human population that is likely to be without an appreciable risk 

of deleterious effects during a lifetime” (USEPA Risk Assessment Glossary, 

http://www.epa.gov/risk_assessment/glossary.htm).

2.4.3 Carcinogenicity/Mutagenicity 

There is no evidence of carcinogenic potential in the rat and mouse carcinogenicity studies, 

and there is no concern for mutagenicity. Based on studies with rats and mice, the USEPA 

has classified imidacloprid into Group E, no evidence of carcinogenicity (USEPA, 2005; 

2013). A study of human lymphocytes exposed to greater than 5,ȝJP/RILPLGDFORSULG

demonstrated a slight increase in chromosome abnormalities in vitro, but this result was not 

found with in vivo tests (Gervais et al., 2010). Imidacloprid is not considered mutagenic or

genotoxic based on the weight of evidence from several in vitro and in vivo studies. The 

results of an in vitro study on human peripheral blood lymphocytes indicated that 

imidacloprid at concentrations less than 20 microMolar is not genotoxic to human 

lymphocytes (Costa et al., 2009). 

2.4.4 Development and Reproductive Effects

A two generation reproductive study using the rat resulted in a NOEL of 13 mg/kg/day for 

adult rats based on a decrease in premating body weights. The offspring NOEL was also 13 

mg/kg/day based on decreased pup body weight in both litters (CA DPR, 2006b). 

Developmental studies using the rat reported a maternal and developmental NOEL of 13 

mg/kg/day, and in a rabbit study, the maternal and developmental NOEL was reported as 24 

mg/kg/day. A chronic fertility study showed that exposure to imidacloprid at doses of 225 

and 112 mg/kg for 60 days can cause histological damage to testicular tissue, sperm 

mortality, and decreased testosterone levels in mature male rats (Najafi et al., 2010). 
2.4.5 Endocrine Effects

A literature search did not identify any study indicating the potential of imidacloprid to affect 

the endocrine system. Imidacloprid is among the group of 58 pesticide active ingredients on 

the initial list to be screened under the USEPA Endocrine Disruptor Screening Program. 

However, the list of chemicals was generated based on exposure potential, not based on 

whether the pesticide is a known or likely potential endocrine disruptor (USEPA, 2014b). 

Imidacloprid is not among the European Union (EU) list of chemicals with the potential to

impact the endocrine system. The EU list includes three categories: Category 1 – endocrinal 

effect recorded at least on one type of animal; Category 2 – a record of biological activity in 

vitro leading to disruption; and Category 3 – not enough evidence or no evidence data to 

confirm/disconfirm endocrinal effect of tested chemicals (Hrouzková and Matisova, 2012).

2.4.6 Immune System Effects

A literature review of earlier studies indicates that imidacloprid does not have a direct effect 

on the immune system in mammals (USDA FS, 2005). Recent studies suggest that exposure 

to imidacloprid may induce immunotoxicity (Mohany et al., 2011; Gawade et al., 2013; 

Badgujar et al., 2013). A study in male albino rats indicated that exposure to 1/100 of the 

LD50 for imidacloprid can induce immunotoxicity, oxidative stress, lipid peroxidation, and 

hepatotoxicity (Mohany et al., 2011). A developmental immunotoxicity study in Wistar rats 

(Gawade et al., 2013) indicated that continuous exposure to imidacloprid during development 

adversely affected the immune system. An oral exposure study in BALB/c mice over 28 

days showed that imidacloprid has immunosuppressive effects at doses >5 mg/kg (Badgujar 

et al., 2013). 

2.4.7 Metabolism 

The imidacloprid molecule (composed of a pyridinyl moiety and an imidazolidine ring) is 

metabolized through two main routes of metabosim. The first route is oxidative cleavage 

that frees the pyridinyl moiety to yield 6-chloronicotinic acid. Then, 6-chloronicotinic acid is 

mostly conjugated with glycine to form a hippuric acid-type conjugate. Minor quantities of 

6-chloronicotinic acid are dechlorinated to form methylmercaptonicotinic acid and 

derivatives. The second route is hydroxylation of the imidazolidine ring to form 4- or 5-

hydroxyl imidacloprid (HSDB, 2014). In mammalian studies imidacloprid has been shown 

to be rapidly excreted in feces and urine. In an oral dosing rat study using radiolabelled 

imidacloprid approximately 90 percent of the radioactivity was excreted through the urine 

and feces within 24 hours, with 96 percent excreted after 48 hours (USDA FS, 2005). 

3.0 DOSE-RESPONSE ASSESSMENT

3.1 Human Health Dose-Response Assessment

A dose-response assessment evaluates the dose levels (toxicity criteria) for potential human 

health effects including acute and chronic toxicities. 

Appendix F. Imidacloprid Environmental Risk Assessment
USEPA derived an acute reference dose (RfD) of 0.14 mg/kg for imidacloprid based on the 

LOAEL of 42 mg/kg body weight divided by an uncertainty factor of 300 (10 for interspecies 

extrapolation, 10 for intraspecies sensitivity, 3 for using a LOAEL to approximate a NOAEL) 

(USEPA, 2010).

USEPA also derived a chronic RfD of 0.057 mg/kg/day based on chronic toxicity and 

carcinogenicity studies using the rat. The NOAEL was estimated to be 5.7 mg/kg/day and the 

LOAEL was set at 16.9 mg/kg/day based on increased occurrence of mineralized particles in the 

thyroid gland of male rats (USEPA, 2010).

USEPA has not established a maximum contaminant level for imidacloprid in water (USEPA, 

2014c). USEPA developed a chronic drinking water level of comparison (DWLOC) (1,755 ppb)

for imidacloprid for an aggregate dietary exposure analysis during registration. The DWLOC 

determines the theoretical upper limits for a pesticide’s concentration in drinking water (USEPA, 

2005)

For the ALB eradication environmental monitoring program in Suffolk County, New York, the 

New York State "Imidacloprid Groundwater Monitoring Project Plan” established an "action 

threshold" of 25 ppb (half of the New York State drinking water standard) for imidacloprid 

(USDA APHIS, 2007). 

3.2 Ecological Effects Analysis

This section of the risk assessment discusses available ecological effects data for terrestrial and 

aquatic biota. Available acute and chronic toxicity data are summarized for all major taxa and 

will be integrated with the exposure analysis section to characterize the risk of imidacloprid to 

nontarget wildlife and domestic animals. Information in this section was gathered from on-line 

databases and searches for relevant peer reviewed and non-peer reviewed literature. In cases 

where multiple toxicity values were located for the same test species, the lowest value was 

generally used in the effects analysis. This was particularly the case for aquatic invertebrate 

toxicity data where multiple acute lethality values were available for the same test species. Other 

values that were not selected were within the range of effects data that was reviewed during the 

literature search.

3.2.1 Aquatic Effects Analysis

3.2.1.1 Fish and Amphibians

Imidacloprid acute toxicity to fish and amphibians is low based on the available acute 

median lethal concentrations (USEPA, 2008; USDA FS, 2005; Feng et al., 2004; Jemec 

et al., 2007) (table 3-1). Values typically exceed 100 mg/L suggesting that imidacloprid is 

practically non-toxic to fish and amphibians. Sublethal toxicity based on available no

observable effect concentrations (NOEC) data ranges from 25 to 58 mg/L for fish with 

effects such as erratic swimming behavior, discoloration, quiescence and labored 

respiration noted at higher concentrations (USDA FS, 2005).
Table 3-1. Acute aquatic vertebrate toxicity data for imidacloprid.

Test Organism Endpoint/Length Toxicity Value 

(mg/L)

NOEC 

(mg/L)

Bluegill 96-hour LC50 >105 25

Rainbow Trout 96-hour LC50 229.1 52.1

Zebrafish 96-hour LC50 241.0 NR

Sheepshead Minnow 96-hour LC50 163 58.2

Rana limnocharis 48-hour LC50 165 30

Rana hallowell 48-hour LC50 219 101.2

Hypsiboas pulchellus 96-hour LC50 84.91 NR

NR = not reported

Limited chronic fish toxicity data is available; however, in a 98-day flow-through 

exposure the rainbow trout LOEC and NOEC were 2.3 and 1.2 mg/L, respectively, based 

on a statistically significant reduction in length (USDA FS, 2005). Sanchez-Bayou and 

Goka (2005) dosed rice paddies at a rate 1.5 times the proposed rate and measured 

several sublethal responses in Japanese medaka over an approximate three month period. 

No statistical analysis was completed; although, the authors noted a lack of 

malformations in imidacloprid treated fields, and did note an increase in parasitism rates 

by the ectoparasite, Trichodenia, when compared to controls. Measured concentrations 

of imidacloprid ranged from 239.2 μg/L immediately after dosing to 1.1 μg/L 118 days 

post treatment. Ruiz de Arcautea et al. (2014) reported various genotoxic effects to 

tadpoles of the Montevideo tree frog, Hypsiboas pulchellus, at concentrations ranging 

from 15 to 45 mg/L in 48 and 96 hour exposures.

3.1.1.2 Aquatic Invertebrates

Aquatic invertebrates are more sensitive to imidacloprid when compared to fish or 

amphibans with acute median toxicity values in the high part per trillion range to greater 

than 100 mg/L depending on the test species (Song et al., 1997; Song and Brown, 1998; 

USDA APHIS, 2002; USEPA, 2008; Overmyer et al., 2005; USDA FS, 2005; Paul et al., 

2006; Key et al., 2007; Alexander et al., 2007; Stoughton et al., 2008; Roessink et al. 

2013) (table 3-2).

Table 3-2. Representative acute aquatic invertebrate toxicity data for imidacloprid.

Test Organism Endpoint/Length Toxicity Value (μg/L) NOEC(μg/L)

Epeorus longimanus 96-hour LC50 0.65 NR

Caenis horaria 96-hour EC50 1.77 NR

Cloeon dipterum 96-hour EC50 1.02 NR

Daphnia magna 48-hour EC50 85200 42000

Daphnia magna 48-hour EC50 10440 NR

Chironomus tentans 96-hour LC50 5.75 1.03

C. tentans 10-day LC50 3.17 0.67

Hyallela azteca 96-hour LC50 65.43 54.24

Appendix F. Imidacloprid Environmental Risk Assessment
H. azteca 96-hour LC50 526.0 0.35

Simulium vittatum 48-hour LC50 6.75 – 9.54 NR

Lumbriculus variegatus 96-hour EC50 6.2 NR

Aedes aegypti (4th

instar)

72-hour LC50 84.0 NR

Aedes aegypti (adult) 72-hour LC50 >6300 NR

A. taeniorhynchus 48-hour LC50 13.0 NR

Mysidopsis bahia 96-hour LC50 38.0 32.0

Palaemonetes pugio 96-hour LC50 308.8 100

Artemia sp. 48-hour LC50 361230 NR

Crassostrea virginica 96-hour EC50 >100000 145000

NR = not reported

Sublethal effects have also been observed for various aquatic invertebrates under acute 

and chronic exposures. Agatz et al. (2014) reported feeding inhibition for Gammarus 

pulex in four day exposures to imidacloprid residues as low as 30 μg/L. Agatz et al. 

(2013) reported similar effects to the cladoceran, D. magna, where 50% reductions in 

feeding occurred at an exposure concentration of 1.83 mg/L. Reduced feeding resulted in 

impacts to survival, growth, and reproduction; however, the presence of surplus food 

after exposure allowed for recovery. In cases of limited food availability, recovery in 

growth was not observed. Alexander et al. (2007) reported feeding inhibition for the 

mayfly, Epeorus longimanus, and the aquatic oligachaete, Lumbriculus variegatus, in 

pulsed 24-hour doses using imidacloprid at concentrations above 0.5 μg/L. Survivorship 

effects were noted at concentrations between 1 and 10 μg/L.

Chronic toxicity to aquatic invertebrates has been assessed in both marine and 

freshwater invertebrate species. In two flow-through studies using M. bahia, the 

maximum allowable toxicant concentration (MATC) values for reproductive success 

ranged from greater than 643 ng/L to 849 ng/L while the MATC for growth ranged 

from 230 to 3806 ng/L (USDA FS, 2005). Stoughton et al. (2008) conducted 28-day 

continuous and pulse dose studies using the midge, C. tentans, and the freshwater 

amphipod, H. azteca. The C. tentans NOECs for survival and weight were both 1.14 

μg/L under continuous exposure and 3.47 μg/L under a pulse dose. H. azteca was 

comparatively less sensitive with a NOEC for survival and weight of 3.44 and 11.46 

μg/L, respectively, under continuous exposure, and a NOEC of 3.53 and 11.93 μg/L for 

the same endpoints under a pulse dose exposure. Chronic toxicity testing using the less 

sensitive D. magna resulted in NOEC and LOEC values of 1.8 and 3.6 mg/L, 

respectively (USEPA, 2008). Pestana et al. (2009) reported reduced leaf litter 

decomposition related to decreased feeding activity by stoneflies after pulsed dose 

exposures in mesocosms receiving three doses of imidacloprid at 17.60 μg/L. No 

effects were observed at the next lowest concentration, 1.63 μg/L. Nyman et al. (2013) 

reported reduced feeding activity and lipid content in 14- and 21-day exposures to the 

amphipod Gammarus pulex exposed to imidacloprid residues as low as 15 μg/L. 

Sublethal impacts to some aquatic invertebrates that feed on leaf litter containing 

imidacloprid have been observed, as well as effects on decomposition rates 
(Kreutzweiser et al., 2007; Kreutzweiser et al., 2008; Kreutzweiser et al., 2009). 

Mortality to leaf-shredding insects occurred at higher rates that were intentionally 

overdosed; however, significant mortality did not occur to shredding insects such as 

Pternarcys dorsata and Tipula sp. at typical field applications. Feeding inhibition was 

observed at imidacloprid leaf concentrations of 18-30 μg/g which have been observed 

in the field under normal applications (Kreutzweiser et al., 2009). 

In a review of a microcosm study that was submitted to support registration of 

imidacloprid negative impacts to some blue green algae, copepods, and several insect 

groups were observed at measured average doses ranging from 19 to 180 μg/L (USDA

FS, 2005). The NOEC based on total number of invertebrates and species richness was 

determined to be 2 μg/L from the study where tanks were dosed biweekly four times. 

3.1.1.3 Aquatic Plants

Aquatic plant studies testing technical and formulated material on blue green algae, 

freshwater diatoms, and green algae have demonstrated low toxicity (USDA FS, 2005; 

USEPA, 2008) (table 3-3).

Table 3-3. Acute aquatic plant toxicity data for imidacloprid.

Test Organism Endpoint/Length Toxicity Value 

(mg/L)

NOEC 

(mg/L)

Anabaena flosaquae* 120-hour EC50 32.8 24.9

Navicula

pelliculosa*

120-hour EC50 NR 6.69

Scenedesmus subspicatus 96-hour EC50 >10 10

Selanastrum capricornutum 120-hour EC50 >119 >119

*Formulated material; NR = Not reported

3.2.2 Terrestrial Effects Analysis

3.2.2.1 Mammals and Birds

Imidacloprid has moderate acute oral toxicity to wild mammals based on the available 

toxicity data used to evaluate human health effects. Imidacloprid is considered toxic to 

birds with acute oral median toxicity values ranging from 41 to 152 mg/kg (USDA 

APHIS, 2002a; USEPA, 2008; USDA FS, 2005) (table 3-4). Reproduction studies using 

the mallard and bobwhite quail have shown NOECs of approximately 125 ppm for both 

species. 

Table 3-4. Acute avian oral and dietary toxicity data for imidacloprid.

Test Species Study LD50/LC50 NOEL/LOEL

House Sparrow Acute Oral 41.0 3.0/NR

Pigeon Acute Oral NR NR/12.5

Canary Acute Oral NR 10.0/NR

Ringed Turtle Dove Subacute Dietary NR NR/228.0

Bobwhite Quail Acute Oral 152.3 25.0

Appendix F. Imidacloprid Environmental Risk Assessment
Subacute Dietary 1535.87 69.0

Chronic Reproductive NA 126.0

Mallard Subacute Dietary 4797.0 69.0

Chronic Reproductive NA 125.0

NR = not reported; NA = not available

3.2.2.2 Reptiles and Amphibians (terrestrial phase)

No acute or chronic toxicity data appears to be available for reptiles or terrestrial phase 

amphibians based on a review of the literature and databases containing toxicity data for 

imidacloprid. Available data for the aquatic phase of amphibians demonstrates low 

toxicity and is comparable to the data for surrogate fish species. In cases where effects 

data are lacking for reptiles USEPA assumes that the sensitivity is comparable to birds 

which would suggest that imidacloprid is toxic to reptiles. There is uncertainty in that 

assumption due to physiological and life history differences between birds and reptiles. 

3.2.2.3 Terrestrial Invertebrates and Soil Microorganisms

A substantial amount of imidacloprid toxicity data has been collected for a variety of 

insects and other arthropods with results varying based on the terrestrial invertebrate 

species tested, the method of application, and other environmental factors (USDA FS, 

2005; Pisa et al., 2015). Most of this data has been collected to assess potential impacts 

to parasitoids and predators to determine compatability of imidacloprid in integrated pest 

management. In general, imidacloprid offers reduced effects to these types of 

invertebrates compared to broad spectrum insecticides. Impacts to susceptible insects 

that feed on treated trees are expected, but due to the method of application and the 

treatment of specific ALB host trees, the effects are expected to be localized and not 

widespread.

Due to concerns with pollinators such as honey bees several toxicity studies have been 

conducted assessing acute and chronic effects of imidacloprid to these species. Technical 

and formulated imidacloprid is considered acutely toxic to honey bees and other related 

bee species by oral and contact exposure. Median lethal toxicity values range from 3.7 to 

230 ng/bee (Schmuck et al., 2001; Tasei, 2002; USDA FS, 2005; USEPA, 2008). Acute 

sublethal effects in laboratory studies have shown that the NOEC may be less than 1 

ng/bee (USDA FS, 2005). Imidacloprid metabolite toxicity to honey bees is variable 

with some of the metabolites having equal toxicity to imidacloprid while other 

metabolites are considered practically non-toxic (USDA FS, 2005). 

Due to concerns regarding the potential sublethal impact of imidacloprid to honey bees, 

several studies have been conducted to determine potential effects in laboratory and field 

situations. Studies to assess the effects of imidacloprid on homing behavior, colony 

development, foraging activity, reproduction, wax/comb production, colony health, as 

well as other endpoints, reveal conflicting results with similar effects not typically 

observed at test concentrations under realistic exposure scenarios (Tasei et al., 2000; 

Tasei et al. 2001; Tasei, 2002; Bortolloti et al., 2003; Maus et al., 2003; Morandin and 
Winston, 2003; Stadler et al, 2003; Schmuck, 2004; Johnson, 2012; Fischer et al., 2014; 

Scholer and Krishik, 2014; Feltham et al., 2014). Blacquière et al. (2012) and Pisa et al. 

(2015) summarize many of these studies with effect concentrations ranging from the low 

μg/bee or μg/kg to greater, depending on the study design and endpoint. Many of the 

effects reported in these laboratory studies have not been reported in the field under more 

realistic exposure conditions (Cresswell, 2010; Blacquière et al., 2012; Fairbrother et al., 

2014). The lack of reported effects in field studies may be due to the limitations in the 

extrapolation of laboratory effects to the field, health of the bees, and the experimental 

design of field studies. The lack of statistical power in the design of field studies may 

lead to incorrect conclusions regarding the lack of effects (Cresswell, 2010; van der Sluijs 

et al., 2013). Recent studies have reported mixed results regarding impacts to pollinators 

at field relevant doses. Feltham et al. (2014) reported a reduction in pollen collection in 

the field for bumblebees exposed in the laboratory to sugar water and pollen imidacloprid 

concentrations of 0.7 and 6.0 μg/L, respectively. No differences were reported for nectar 

collection efficiency between controls and imidacloprid exposed bees. 

Imidacloprid lethality and sublethal studies have been conducted with various earthworm 

species. Lethality varies with LC50 values ranging from 1.5 to 25.5 ppm (Pisa et al., 

2015). Sublethal effects have been noted in various earthworm species as well. Effects 

on reproduction and behavior, such as burrowing, have been noted in various species and 

under various exposure conditions with effects seen at concentration ranging from 0.1 

ppm and above (Bhattacharya and Sahyu, 2013; Pisa et al., 2015). Earthworm studies 

testing the effects of imidacloprid applied for the ALB have reported effects in both soil 

and trunk injections. Kreutzweiser et al. (2009) reported no mortality to earthworms that 

were fed scenescent leaves from trunk injected maple trees containing 3 to 11 mg/kg of 

imidacloprid. However they did report sublethal impacts such as antifeeding behavior 

and earthworm weight loss in addition to reduced leaf litter degradation. In soil treatment 

studies using imidacloprid applied for ALB control a LC10 and LC50 of 2 and 5.7 mg/kg, 

respectively, were reported for, the earthworm Dendrobaena octaedra. Sublethal effects 

such as weight loss were reported at 3 mg/kg. The other earthworm species tested, 

Eisenia fetida, was less sensitive with a reported LC50 of 25 mg/kg and sublethal effects 

noted at 14 mg/kg (Kreutzweiser et al., 2008).

3.2.2.4 Terrestrial Plants

Toxicity testing using terrestrial plants is not typically required in the registration of 

insecticides and little data exists regarding potential effects. Of the available data, no

impacts to treated terrestrial plants have been noted in forestry or agricultural settings 

(Westwood et al., 1998; USDA FS, 2005).

3.2.3 Toxicity of formulations and metabolites to nontarget wildlife 

The aquatic toxicity of the primary metabolites of imidacloprid in the environment which are 

urea-based metabolites, designated as NTN 33823 and NTN 33519, and 6-chloronicotinic 

acid have been evaluated for H. azteca and C. tentans which represent the more sensitive 

aquatic species. Based on the range of toxicity values for each of the metabolites compared 

Appendix F. Imidacloprid Environmental Risk Assessment
to imidacloprid, the toxicity for each metabolite is several orders of magnitude less than the 

parent (USDA FS, 2005) (table 3-5). 

Table 3-5. Comparative aquatic toxicity data for imidacloprid and associated metabolites.

Test Species Chemical Endpoint/Length Toxicity Value 

(μg/L)

NOEC

(μg/L)

Hyallela azteca imidacloprid 96-hour LC50 526.0 0.35

NTN 33823 96-hour LC50 51800 22100

NTN 33519 96-hour LC50 >94830 94830

C. tentans imidacloprid 96-hour LC50 5.75 1.03

NTN 33823 96-hour LC50 >82800 8190

NTN 33519 96-hour LC50 >99800 99800

6-chloronicotinic acid 96-hour LC50 >1000 1000

Formulation aquatic toxicity data does not appear to be available for Merit®, or some of 

the other available formulations for use against ALB; however, aquatic toxicity data with 

other formulations containing imidacloprid have demonstrated comparable, or increased

aquatic toxicity in studies conducted with the technical material (Stoughton et al., 2008). 

The complete list of inerts is considered confidential business information and therefore 

is currently not available for review for most formulations. The material safety data sheet 

for Merit® states that glycerin is present although the exact quantity is unknown. 

4.0 EXPOSURE ASSESSMENT

4.1 Human Health Exposure Assessment

Exposure assessments estimate the potential exposure of humans to imidacloprid. The exposure 

assessment begins with the use and application method for imidacloprid. An identified exposure 

pathway for imidacloprid includes (1) a release from an imidacloprid source, (2) an exposure 

point where contact can occur, and (3) an exposure route such as ingestion, inhalation, or dermal 

contact (USEPA 1989). Exposures for the various subgroups of the population are qualitatively 

evaluated for each identified exposure pathway.

4.1.1 Identification of Potentially Exposed Human Populations and Complete 

Exposure Pathways

Based on the expected use pattern for both types of imidacloprid applications (trunk or soil 

injection), applicators and workers in the program who are mixing and applying the 

insecticide in the field are the most likely subgroup of the human population to be exposed to 

imidacloprid. Exposure during transportation is not anticipated because the container of the 

concentrated material is sealed. Following label directions including the use of proper 

personal protective equipment (PPE) will minimize exposure to workers. Accidental 

exposure may occur during mixing and applying the formulation. Under an accidental spill 

scenario, workers may be exposed to imidacloprid through dermal contact. However, the 

potential dermal contact exposure is anticipated to be limited because these accidental events 

would be of low frequency and short duration.
In addition to worker exposure there is the possibility of exposure to residents in areas during 

and after treatment. Generally, exposure to residents during treatment is not expected based 

on the method of application (trunk and soil injection). Exposure to residents whose property 

may be treated can be minimized through proper notification prior to treatment. Therefore, a 

significant exposure pathway is not identified for direct contact to imidacloprid for the 

general public. A significant exposure pathway is not identified for dietary plant 

consumption because treated trees will not have products harvested for human consumption.

There is the potential for dietary exposure to the public in cases where treated that are used in

the production of maple syrup; however, this is not a registered use for imidacloprid and this 

type of exposure would not be expected to occur. The soil injection application method may 

result in potential exposure to imidacloprid for children who exhibit pica, the recurrent 

ingestion of unusually high amounts of soil, on the order of 1,000-5,000 mg/day or more 

(USEPA, 2011)). In addition, there is the potential for children and adults to be exposed to 

residual imidacloprid in leaf litter. The environmental monitoring data indicates that 

imidacloprid can persist in treated trees for at least 12 months after treatment. Chemical 

uptake occurs throughout the tree with higher residues detected in leaf samples than twig 

samples for most species of trees sampled (USDA APHIS, 2002). 

A significant exposure pathway is not idenified for groundwater or surface water media 

under the trunk injection use pattern. Imidacloprid is soluble and has the potential to leach 

from soil to groundwater under the soil injection use pattern. Groundwater sampling 

between 2003 and 2006 in Suffolk County, New York, demonstrated that approximately half 

of the water samples had no detectable levels of imidacloprid. Of those where detections 

occurred, the average concentration was 3.2 parts per billion (ppb) which is below the level 

of concern for human health (USDA APHIS, 2007). Samples with detectable levels of 

imidacloprid do not suggest a contribution from the ALB eradication program because other 

uses of imidacloprid occurred in these areas, and there did not appear to be a significant 

correlation between ALB-related treatment activities and increased residues (USDA APHIS,

2013). In addition, significant surface runoff into aquatic resources is not expected based on 

the trunk and soil injection use pattern (USDA FS, 2005).

4.1.2 Exposure Evaluation

This section quantitatively evaluates the worker exposures from direct contact pathways 

while applying imidacloprid using trunk and soil injection. 

The proposed use pattern for imidacloprid in the ALB program involves soil injection 

applications using the Merit® 2F, or similar, formulation. The rate of application for Merit®

2F is 3-6 ml (0.1-0.2 fl oz) per inch of trunk diameter at breast height with a maximum use 

rate of 25.6 fl oz product/acre/year. The formulation is applied in water in sufficient 

quantities to adequately moisten the soil near the base of the tree but not saturate the soil 

which could increase the likelihood of off-site transport. Due to the method of application, 

exposure from drift is not expected. Exposure to applicators will be minimal based on the 

method of application, following the label regarding PPE, and the environmental fate of 

imidacloprid which reduces exposure via inhalation, dermal, and oral routes. To quantify the 

Appendix F. Imidacloprid Environmental Risk Assessment
potential exposure to workers making ground applications using imidacloprid, estimated 

doses were derived based on methods developed by the U.S. Forest Service, and in particular,

those that were developed to assess human health risks to imidacloprid (USDA FS, 2005; 

SERA, 2005). A lower and upper bound estimate of exposure was estimated based on 

assumptions regarding the amount of time and product that is applied during a typical work 

day.

To quantify the potential exposure to a child from soil ingestion and dermal contact to leaf 

litter, the soil (lower and average concentrations of 0.13 ppm and 1.32 ppm, respectively) and 

leaf litter (average and maximum concentrations of 1.966 ppm and 97.5 ppm, respectively) 

data from the APHIS ALB environmental monitoring program were used.

4.2 Ecological Exposure Assessment

4.2.1 Aquatic Exposure Assessment

Exposure to aquatic organisms will occur primarily from either runoff related to soil 

applications or from leaf litter that may be deposited into waterbodies. Drift is not expected 

to be an exposure pathway based on the method of application. Estimating residues that 

could occur from leaf deposition into water bodies is difficult to quantify using standardized 

environmental fate models. Aquatic residues from soil injection are based on estimates from 

the U.S. Forest Service that were modeled for various soil types, precipitation levels and 

water bodies (USDA FS 2005). Average estimated aquatic residues in ponds ranged from 

1.49 x 10-7 ppb under low annual rainfall (25 in) to 0.308 ppb under high annual rainfall (250 

in). Concentrations were less in small streams with average imidacloprid levels of 1.09 x 10-

8 ppb under low rainfall levels to 0.0829 ppb under high annual rainfall levels. Yearly 

rainfall levels of 25 inches or less resulted in no detectable levels of imidacloprid. This range 

of values is based on the assumption of a one pound per acre application applied to one acre 

of land adjacent to an aquatic habitat. Residues could increase as the amount of acreage 

treated relative to the size of the water body increases; however, as the treatment is moved 

further away from the water body more rainfall would be needed to transport imidacloprid. 

This range of estimated residues was compared to the available effects data for imidacloprid 

in the aquatic risk characterization section of this assessment.

4.2.2 Terrestrial Exposure Assessment

Exposure to mammals and birds will be primarily through dietary exposure from consuming 

treated vegetation or invertebrates that consume treated vegetation, or are present in the soil 

where applications may occur. Dermal and inhalation exposure for mammals and birds is not 

expected based on the method of application and environmental fate of imidacloprid. Dietary 

exposure would be greatest for those mammals and birds that feed exclusively on vegetation 

from treated trees. Average and maximum residues for imidacloprid are 1.966 ppm and 97.5 

ppm, respectively, based on environmental monitoring that has been done by the program. 

Honeybees and other pollinators may be exposed to imidacloprid from nectar and pollen. 

Exposure honeybees to imidacloprid from water is expected to be minor based on the 
methods of application. Field monitoring data from trees treated with imidacloprid during 

the ALB eradication program suggest exposure levels will be low (Johnson, 2012). Pollen 

samples collected from trees treated with imidacloprid through soil injection revealed 

residues below the level of detection (1.0 ppb) to approximately 30.6 ppb with an average 

concentration of 5.31 ppb. Greater than 50% of the samples collected from treated trees 

contained levels below detection. Pollen samples collected from trees treated with 

imidacloprid through trunk injected trees were comparably lower, ranging from below 

detection to 1.5 ppb with an average concentration of 0.28 ppb. Greater than two-thirds of 

the pollen samples had levels below detection. The residues collected from this study fall 

within the low range of imidacloprid residues that have been reported in pollen samples from 

agricultural crops where imidacloprid is applied as a seed treatment or a broadcast 

application (Bonmatin et al., 2015). Nectar samples collected from honeybee hives in the 

ALB-treated tree study revealed no detectable levels of imidacloprid or its metabolites.

5.0 RISK CHARACTERIZATION

5.1 Human Health 

Risks associated with human health are characterized quantitatively for complete exposure 

pathways in this section. Under the PPQ proposed use, imidacloprid use to control ALB 

populations poses minimal risk to human health when applications are made according to label 

directions.

Estimated exposure doses were based on methods developed for imidacloprid by the U.S. Forest 

Service methods to quantify the potential risk to workers making ground applications of 

imidacloprid (USDA FS, 2005; SERA, 2005). A lower and upper bound estimate of exposure 

was based on assumptions regarding the amount of time and product that is applied during a 

typical work day. The exposure estimate was then compared to the acute (0.14 mg/kg/day) and 

chronic (0.057 mg/kg/day) reference dose to calculate hazard quotient (HQ) values.

Both acute and chronic HQ values were below one under all scenarios suggesting minimal risk to 

workers making applications of imidacloprid (table 5-1).

Table 5-1. Hazard quotient values estimated for workers making imidacloprid applications.

Lower Estimate Central Estimate Upper Estimate

Hours of Application/Day 6 7 8

Acres Treated/Day 48 77 144

Adsorbed Dose Rate

(mg/kg per lb a.i. /day)

0.00001 0.0002 0.0009

Adsorbed Dose (mg/kg bw/day) 1.92 x 10-4 6.16 x10-3 5.18 x10-2

Acute Hazard Quotient 0.001 0.04 0.4

Chronic Hazard Quotient 0.003 0.1 0.9

Appendix F. Imidacloprid Environmental Risk Assessment
To quantify the HQ from the unusual soil ingestion behavior (pica) and leaf litter ingestion by 

children (age 1-6), soil concentrations were estimated using the application dosage for a soil 

injection scenario. The estimated soil concentrations were compared to the soil concentrations 

collected from the environmental monitoring reports. The imidacloprid concentations from the 

soil monitoring data are higher and were used for the risk estimation. The leaf litter data 

collected from the monitoring reports was also used for estimating risk from those types of 

exposures. HQ values were calculated using the following USEPA soil ingestion risk estimation 

equation for non-carcinogens:

Acute Hazard Quotient = (Soil/Leaf Litter Concentration x Soil/Leaf Ingestion Rate)/ Body 

Weight or

Chronic Hazard Quotient = (Soil/Leaf Litter Concentration x Soil/Leaf Ingestion Rate x 

Exposure Duration x Exposure Frequency x Conversion Factor)/(Averaging Time x Body 

Weight x Reference Dose) (USEPA 2002). 

The calculated acute and chronic HQ values were below one under all scenarios suggesting 

minimal risk to imidacloprid from soil or leaf litter ingestion by children. The upper estimate 

represents the maximum amount of fluid per acre in a single application (table 5-2). 

Table 5-2. Hazard quotient values estimated for children exposures to soil and leaf litter.

Lower Estimate Upper Estimate

Application Dosage for Soil Injection less than 6.0 fl oz per acre in a single application and 2 

pounds of imidacloprid per gallon

Estimated Soil Concentration 0.0445 mg/kg 0.089 mg/kg

Soil Monitoring Data 0.13 mg/kg 1.32 mg/kg

Leaf Litter Concentration

Acute Hazard Quotient

Soil

Leaf Litter

1.966 mg/kg

0.1

0.02

97.5 mg/kg

1

1

Chronic Hazard Quotient

Soil

Leaf Litter

0.0008

0.01

0.008

0.7

Note: A default soil bulk density of 1.55 g/cm3 for silt loams, and silty clay loams soil (USDA NRCS, 2014) 

was used to estimate soil concentration. 

The risks for the general public from potential exposure to imidacloprid during application are 

not quantified because of minimal potential for exposure and low exposure frequency and 

duration if potential exposure occurs. Dietary consumption of maple syrup from trees treated 

with imidacloprid is not expected because that is not a labelled use and those trees would not 

receive treatment. Consequently, the potential adverse health risks for the general public are 

expected to be minimal.
The risks to the general public from potential exposure to imidacloprid released to soil and 

transported to surface water or groundwater are not quantified because of the low surface runoff 

potential based on the proposed use pattern.

5.2 Aquatic and Terrestrial Ecological Risk Characterization

This section of the risk assessment will integrate the effects analysis, regarding toxicological 

studies summarized for terrestrial and aquatic nontarget organisms, with the potential for 

exposure, to quantify the risk to nontarget organisms and domestic animals from program use of 

imidacloprid. Direct risk refers to those risks that could occur from direct exposure to 

imidacloprid while indirect risk refers to impacts that could occur to prey or habitat that 

nontarget organisms rely on for food and shelter. Impacts to individuals and populations are not 

anticipated in cases where the range of imidacloprid toxicity data to imidacloprid does not 

overlap the range of potential exposure values. Further evaluation of the assumptions used in the 

risk characterization is required to refine risk where residues exceed the response data. 

5.2.1 Aquatic 

The potential risk of imidacloprid applications to aquatic environments is low for tree and 

soil injections. The low risk to these types of habitats is related to the methods of application 

proposed for ALB where trees are injected directly with imidacloprid or the chemical is 

injected into the soil under the dripline of the tree. Drift and runoff are not anticipated to be 

major pathways for off-site transport of imidacloprid to aquatic environments. There is a 

greater chance for runoff from soil injections compared to tree injections; however, the label 

restrictions and estimates of residues when compared to the available toxicity data show the 

risk to be low (Figure 2). The range of effects data discussed in the response section was 

compared to the residue values estimated by the U.S. Forest Service for soil injections in 

various soil types, and water bodies, under various annual rainfall amounts. The comparison 

of the two data sets suggests that acute and chronic risk to aquatic organisms from soil 

application of imidacloprid would be low based on the assumptions used in the exposure 

modeling. 

Appendix F. Imidacloprid Environmental Risk Assessment
Figure 2. Aquatic risk characterization for imidacloprid soil applications.

The greatest potential for residues to reach aquatic habitats is from the leaves of treated trees. 

Acute risk of direct effects to fish and amphibians is very low with an increase in risk to 

aquatic invertebrates from this pathway. Impacts to aquatic invertebrates can result in 

indirect effects to fish and amphibians that rely on invertebrates as a food source. Previous 

research has indicated that lethal effects from this pathway are not expected based on field 

observed levels of imidacloprid in leaf litter deposited in water bodies (Kreutzweiser et al.,

2007; Kreutzweiser et al., 2008a; Kreutzweiser et al., 2009). However some sublethal 

impacts, such as cessation of feeding, have been noted (Kreutzweiser et al., 2009).

5.2.2 Terrestrial Wildlife and Domestic Animals

The direct risk of imidacloprid to mammals and birds is expected to be low based on the 

available toxicity data and the method of application and label requirements that reduce the 

potential for dietary exposure. This would include domestic animals such as dogs and cats 

which would not be expected to forage on treated plants or soil under trees that have been 

treated. Vegetation collected from previous program treatments show average and 

maximum concentrations of 1.966 ppm and 97.5 ppm, respectively. Plausible exposure 

scenarios for wild mammals and birds from either tree injections or soil treatments is difficult 

to quantify; however, the direct risk to nontarget wildlife is expected to be low based on the 

available toxicity data and methods of application (USDA FS, 2005). Not all trees and other 

plant food sources for wild mammals and birds will be treated; therefore, exposure to 

imidacloprid treated vegetation will be reduced since other non-treated plants will be within 

the home range of most mammals and birds. 

A recent review of published studies regarding direct and indirect risk to vertebrates from 

imidacloprid use suggests that environmental exposure levels are below concentrations that 

1E-08 0.000001 0.0001 0.01 1 100 10000 1000000

Log Imidacloprid Concentrations (μg/L) 

Sublethal/Chronic Fish Effects 

Sublethal/Chronic Invertebrate Effects 

Acute Invertebrate Effects 

Estimated Acute Aquatic Concentrations 

Acute Fish Effects 
would result in mortality and most reported sublethal effects (Gibbons et al., 2014). There is 

some uncertainty regarding the lack of risk due to the extrapolation of available toxicity data 

and sublethal impacts from one animal group to another or from one use pattern to another. 

Mineau and Palmer (2013) discuss similar direct and indirect risks regarding impacts to 

birds; however, the emphasis of that work was related to seed treatments using imidacloprid 

as well as other neonicotinoid insecticides. Direct risk to birds and mammals from 

imidacloprid treatments in the ALB program would be expected to be comparatively lower 

than seed treatments. Treated seed that is exposed on the ground during planting operations 

in agricultural settings would be more attractive to seed eating birds and mammals resulting 

in greater exposure. In addition, imidacloprid use would occur within a field with little to no 

alternative imidacloprid residue-free seed sources available for foraging birds. This would 

not be the case with imidacloprid treatments from tree or soil injections as part of the ALB 

program. Select trees are treated within a given area based on site-specific needs, and other 

non-treated trees and plants producing seed would be available for foraging by birds and 

mammals. However, there is the possibility that imidacloprid treated trees could result in 

measurable residues in tree seeds. This risk is expected to be low, especially for maples, that 

are not preferred food sources for most seed eating birds and mammals compared to other 

plant species (Rodewald and Abrams, 2002). In addition, maple seeds degrade more quickly 

than hard mast seeds, such as acorns, and would not be available for foraging. Terrestrial 

vertebrates that eat insects and other terrestrial invertebrate species may also be exposed to 

imidacloprid from foraging on species that have consumed plant material from treated trees. 

The risks to terrestrial vertebrates from this type of exposure is expected to be low due to 

several factors. Exposure to most insectivorous vertebrates would be low because there 

would be unexposed invertebrate because the ALB program does not treat all plant material 

in an area. In cases of soil injections, there would also be the potential for soil inhabiting 

invertebrates that occur under the tree dripline to be exposed; however, these would be 

localized to areas within the dripline of an individual tree and would not be area wide. In 

addition, most vertebrates that feed on invertebrates would preferentially consume live prey 

compared to those that had received lethal doses of imidacloprid.

Indirect risk to terrestrial vertebrates through the loss of prey items is also not anticipated to 

be a significant risk because only invertebrates that consume treated material would be 

potentially impacted by imidacloprid. Thus, many invertebrates with no imidacloprid 

residues would occur in an area to provide a food source to insectivorous terrestrial 

vertebrates. Also, invertebrates that occupy treated trees but do not feed on the leaves and 

twigs would not be impacted by imidacloprid. This would also be the case for soil inhabiting 

invertebrates that may occur under the dripline of trees that are treated with imidacloprid 

using soil injection. Falcone and DeWald (2010) evaluated the impacts of imidacloprid 

broadcast treatments on invertebrate prey items for several neotropical bird species in areas 

where the invasive balsam wooly adelgid occurs. Hemipteran and lepidopteran abundance 

declined in treated areas versus control areas, but species richness and composition was 

similar between treated and nontreated blocks. Total bird abundance for the species 

evaluated did not differ between treated and untreated areas, suggesting that these species 

were able to forage on other arthropods in treated blocks. These types of impacts would not 

be anticipated in the ALB program because imidacloprid is not being applied using broadcast 

applications.

Appendix F. Imidacloprid Environmental Risk Assessment
5.2.3 Terrestrial Invertebrates and Plants

Risks to terrestrial invertebrates will vary based on the method of application. Soil 

inhabiting invertebrates such as earthworms will be at greater risk from imidacloprid soil 

applications compared to tree injections. Imidacloprid residue data that has been collected as 

part of the ALB eradication program from various locations report an average soil 

concentration of 1.32 ppm with a maximum value of 43 ppm. Soil injection sites will have 

elevated imidaclprid levels compared to the area under the tree canopy drip line. The 

reported average soil imidacloprid values are within the range of lethal (LC50 > 1.5 ppm) and 

sublethal (> 0.1 ppm) effects data threshold concentrations, suggesting risk to earthworms. 

The risk to earthworms in the field will be affected by site-specific conditions that could 

impact exposure concentration and duration. Any impacts are expected to be restricted to 

areas where imidacloprid has been injected into the soil under the dripline of trees where 

applications would occur. 

Terrestrial invertebrates that are sensitive to imidacloprid and consume plant material from 

treated trees are expected to be impacted; however, based on the method of application and 

the mode of action for imidacloprid, these risks will be reduced when compared to making 

broadcast applications. Risks to pollinators are expected to be low based on the available 

residue data that has been collected for pollen from trees treated with imidacloprid either 

through trunk or soil injection and the lack of detectable residues in nectar (Johnson, 2012). 

Mean imidacloprid pollen levels were 1.5 and 5.31 ppb in trunk and soil injected trees, 

respectively. These residues are below a majority of the sublethal effects data for similar 

types of exposure. In addition, more than half of the pollen samples in both treatment 

methods contained no detectable levels of imidacloprid and none of the nectar samples 

contained detectable levels of imidacloprid. Pollen data collected from bees in the same 

study suggest that other sources of pollen are being utilized, further reducing exposure to 

foraging bees, as well as other bee life stages. Pollen traps used to collect pollen from 

foraging bees at the entrance to the hives demonstrated that the percentage of pollen from red 

maples, a preferred ALB host tree, ranged from 16 to approximately 63 percent. Pollen 

sources from other plants that are not treated with imidacloprid will further reduce exposure 

to foraging bees as well as individuals within the hive. Exposure and risk to honeybees that 

forage on imidacloprid treated trees would be low due to the low residues that have been 

reported and the frequency of imidacloprid levels below detection observed in nectar and 

pollen. In addition there would also be pollen sources from plants that have not been treated 

with imidacloprid that honey bees would use. 

Direct risk to plants is expected to be low based on the method of application to selective 

trees, and the lack of direct toxicity to terrestrial plants. Indirect risks to terrestrial plants 

from potential impacts to pollinators is also expected to be low based on the available data 

regarding imidacloprid pollen and nectar levels in imidacloprid treated trees. Invertebrates 

that may feed on treated trees, and are considered pollinators, may be impacted if they are 

sensitive to the effects of imidacloprid. However, impacts to the pollination of terrestrial 

plants would be minor because most plants have various pollinators, many of which would 
not be exposed to any imidacloprid residues because they would not consume leaves or twigs 

from treated trees. 

6.0 UNCERTAINTIES AND CUMULATIVE IMPACTS

The uncertainties associated with this risk evaluation arise primarily from lack of information 

about the effects of imidacloprid, its formulations, metabolites, and potential mixtures to nontarget organisms that can occur in the environment. These uncertainties are not unique to this 

assessment but are consistent with uncertainties in human health and ecological risk assessments 

with any environmental stressor. In addition, there is uncertainty in where an ALB infestation 

may occur in the United States and the extent of imidacloprid use in a given infestation because 

its use is based on site-specific factors. 

Another area of uncertainty is the potential for cumulative impacts to human health and the 

environment from the proposed use of imidacloprid in the ALB program. Areas where 

cumulative impacts could occur are: 1) repeated worker and environmental exposures to 

imidacloprid from program activities in conjunction with other crop use sources; 2) co-exposure 

to other chemicals with a similar mode of action; and 3) exposures to other chemicals in mixtures 

and how that may affect the toxicity of imidacloprid.

Cumulative impacts may occur from imidacloprid use from other APHIS programs and in 

relation to other chemicals that have a similar mode of action, as well as others that have a 

different mode of action, that can result in synergism, potentiation, additivity or antagonistic 

effects. Other neonicotinoid insecticides include thiamethoxam, clothianidin, dinotefuran,

nitenpyram, acetamiprid, and thiacloprid (Goulson, 2013). Temporal variability in the 

occurrence of multiple stressors, as well as their effects, are not well understood. As an example, 

available water quality monitoring data in the United States indicate the presence of multiple 

natural and anthropogenic contaminants. Sources for these chemicals can occur from point and 

non-point sources, and the relative contribution from each is dependent on land use in a given 

watershed. Based on the most recent United States Geological Survey National Water Quality 

Assessment (USGS–NAWQA) data for pesticides, frequency of occurrence for two or more 

pesticides in surface water exceeds 80% nationally (Gilliom et al., 2006). When considering 

other organics and trace metals, the combination of mixtures can become extremely large, 

especially when spatial and temporal variability in mixtures that can occur in a given watershed 

are considered. The seasonal variability in mixtures of pesticides and other contaminants has 

been well documented nationally in urban and agricultural areas (Ryberg et al., 2010; Gilliom et 

al., 2006; Stone et al., 2014). An analysis of all detections from agricultural streams indicated 

more than 6,000 unique mixtures of 5 pesticides (Gilliom et al., 2006). As would be expected, 

based on the large variability in mixtures, the ecological and human health response data for 

these types of exposure scenarios is very limited for all organic and inorganic chemicals 

including those proposed in the program.

From a human health perspective, the ALB program use of imidacloprid is expected to have

negligible cumulative impacts. The proposed trunk and soil injection use of imidacloprid in the 

ALB progam is unlikely to enter the food chain or drinking water and be available to 

significantly add to imidacloprid exposure in the human population, or occur with other naturally 

Appendix F. Imidacloprid Environmental Risk Assessment
occurring or synthetic compounds that could result in acute or long-term impacts. Use of 

imidacloprid and other neonicotinoids on animals is another exposure source. Repeated chronic 

exposure to imidacloprid from pet medicine may pose possible health risks to veterinarians, 

veterinary technologists, dog caretakers, and owners (Craig et al., 2005). However, due to the 

low probability of imidacloprid exposure to the human population from applications as part of 

the ALB program, the potential for significant cumulative impacts would be minor. 

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Appendix F. Imidacloprid Environmental Risk Assessment

Appendix G. Acronyms and Glossary

 

A

Having a sudden onset, sharp rise, and short course

Pleasing in appearance, relating to or dealing with the beautiful.

Asian Longhorned Beetle

Rivers designated by the U.S. Environmental Protection Agency to receive 

special attention to further three objectives: natural resource and 

environmental protection, economic revitalization, and historic and 

cultural preservation. 

Animal and Plant Health Inspection Service; an agency within the U.S. 

Department of Agriculture. 

The amount of pesticide product applied per unit area. 

Air Quality Index

Of, in, or relating to water. 

There are 13 genera of host trees that APHIS regulates for ALB and are 

considered high-risk hosts: Acer (maple and box elder), Aesculus (horse 

chestnut and buckeye), Salix (willow), Ulmus (elm), Betula (birch), 

Albizia (mimosa), Celtis (hackberry), Cercidiphyllum (katsura tree), 

Fraxinus (ash), Koelreuteria (golden raintree), Platanus (sycamore and 

London planetree), Sorbus (mountain ash), and Populus (poplar). These 

trees are hosts because ALB can derive its food supply from them and 

complete its life cycle.

B

The area of a given section of land that is occupied by the cross-section of 

tree trunks and stems at their base.

Black carbon is a particulate matter (PM) air pollutant formed by the 

incomplete combustion of fossil fuels, biofuels, and biomass.

Bird Conservation Region

ALB

Application

Rate

APHIS

Asian 

Longhorned 

Beetle HighRisk Host Tree

Aesthetic

American

Heritage 

River

Aquatic

Basal Area

Acute

AQI

BC

BCR

Appendix G. Acronyms and Glossary G–1
Butoxyethyl ester

A set of preventative measures used to protect soil and water quality from 

human disturbance.

The number and variety of different organisms in the ecological 

complexes of which those organisms occur naturally; the relative 

abundance and frequency of biological organisms within ecosystems.

The reduction of pest populations by means of living organisms 

introduced or supplemented by humans; utilizes competitors, parasites, 

predators, or sterile insects to reduce pest populations (also called 

biocontrol).

Document stating the opinions of the U.S. Fish and Wildlife Service and 

the National Marine Fisheries Service as to whether a Federal action is 

likely to jeopardize the continued existence of a threatened or endangered 

species or result in the destruction or adverse modification of critical

habitat.

C

Centigrade or Celsius 

Clean Air Act 

A cylindrical layer of tissue in the stems and roots of many seed-bearing 

plants, consisting of cells that divide rapidly to form new layers of tissue.

The uppermost layer in a forest, formed by the crowns of the trees.

A substance capable of causing cancer in living tissue.

Colony Collapse Disorder

Council on Environmental Quality

Code of Federal Regulations (U.S.)

Methane

An adverse reaction(s) of a person or organism to ambient levels of toxic 

substance(s) contained in environmental media such as air, food, soil, and 

water.

CFR

Biodiversity

Biological

Control

Chemical 

Sensitivity

Best 

Management

Practices

oC

CAA

CCD

CEQ

Biological

Opinion

Cambium

Canopy

Carcinogen/

Carcinogenic

CH4

BEE

G–2 Appendix G. Acronyms and Glossary
Marked by long duration, by frequent recurrence over a long time, and 

often by slowly progressing seriousness.

Carbon Monoxide

Carbon Dioxide

The process of burning something.

An assemblage of populations of plants, animals, bacteria, and fungi that 

live in an environment and interact with one another, forming a distinctive 

living system with its own composition, structure, environmental relations, 

development, and function; an association of interacting populations, 

usually defined by the nature of their interaction or the place in which they 

live.

The ratio of the mass or volume of a solute to the mass or volume of the 

solution or solvent; the amount of active ingredient or herbicide equivalent 

in a quantity of diluent (e.g., expressed as lb/gal, ml/liter, etc.), or an 

amount of a substance in a specified amount of medium (e.g., air and 

water).

A tree that bears cones and evergreen needlelike or scalelike leaves.

State agriculture or forestry officials, contractors, and other entities 

collaborating with APHIS.

Clean Water Act

Coastal Zone Management Act

D

Something that sheds after a period of time, such as a tree or a shrub that 

sheds its leaves annually.

A route by which substances can enter the body through the skin.

E

Environmental Assessment; a concise public document which provides 

sufficient evidence and analysis for determining whether to prepare an EIS 

or Finding of No Significant Impact. It aids in compliance with the 

National Environmental Policy Act (NEPA) when no EIS is needed. 

Chronic

Concentration

Cooperator

CWA

CZMA

Community

CO2

Combustion

Conifer

CO

Dermal 

Absorption

Deciduous

EA

Appendix G. Acronyms and Glossary G–3
A biological community of interacting organisms and their physical 

environment.

The potential impact on an ecosystem from the release of toxic substances.

Environmental Impact Statement; a document prepared by a Federal 

agency in which anticipated environmental effects of alternative planned 

courses of action are evaluated; a detailed written statement as required by 

section 102(2)(C) of the National Environmental Policy Act (NEPA). 

The complete destruction or elimination of something.

Executive Order 

U.S. Environmental Protection Agency 

Endangered Species Act

F

Fahrenheit 

An area of low-lying ground adjacent to a river, formed mainly of river 

sediments and subject to flooding.

Plant leaves, collectively.

Finding of no significant impact

Federal Register

Debris or excrement produced by insects.

Forest Service; an agency of the U.S. Department of Agriculture.

U.S. Federal Highway Administration 

Fish and Wildlife Service; an agency of the U.S. Department of Interior.

G

Gram

Greenhouse gas

EIS

EO

EPA

ESA

Eradication

Ecosystem

Ecotoxicity

oF

FR

FS

FWHA

FWS

Frass

Floodplain

Foliage

FONSI

g

GHG

G–4 Appendix G. Acronyms and Glossary
A gas that contributes to the greenhouse effect by absorbing infrared 

radiation.

Gigaton

H

A flowering tree that produces seed within an enclosure such as a fruit. It 

produces hard, compact wood or timber. Examples include oak, cherry, 

maple, or mahogany. 

The older, harder, nonliving, central wood of trees that is usually darker, 

denser, less permeable, and more durable than the surrounding sapwood.

A substance used to kill plants. 

Human Health and Ecological Risk Assessment

The science that studies the occurrence, circulation, distribution, and 

properties of the waters of the earth and its atmosphere.

A state of altered reactivity in which the body reacts with an exaggerated 

immune response to what is perceived as a foreign substance.

I

To burn or reduce to ashes. 

The state of being invaded or overrun by pests or parasites. It can also 

refer to the actual organisms living on or within a host.

The act of inhaling or breathing in.

A substance used to kill insects. 

An animal lacking a backbone, such as an insect, snail, mussel, worm, etc.

International Plant Protection Convention

International standards for phytosanitary measures

Gt

HHERA

Herbicide

Greenhouse

Gas (GHG)

Hardwood Tree

Heartwood

Hydrology

Hypersensitivity

IPPC

ISPM

Insecticide

Infestation

Inhalation

Invertebrate

Incineration

Appendix G. Acronyms and Glossary G–5
K

A species whose presence and role within an ecosystem has a

disproportionate effect on other organisms within the ecosystem.

Kilogram

L

The active immature form of an insect, especially one that differs greatly 

from the adult and forms the stage between egg and pupa.

Liter 

M

Breakdown products of a chemical.

Meter

Microgram

Milligram

Memorandum of Understanding

An agent, such as radiation or a chemical substance, that causes genetic 

mutation. 

N

Nitrous oxide

National Ambient Air Quality Standards

A class of neuro-active insecticides chemically similar to nicotine. The 

insecticide imidacloprid is a neonicotinoid. 

A bird that breeds in Canada and the United States in the summer, and 

spends winter in Central America, South America, or the Caribbean 

Islands. 

The National Environmental Policy Act of 1969 and subsequent 

amendments.

Kg

μ

L

mg

MOU

m

Metabolite

Keystone 

Species

Larva

Mutagen/

Mutagenic

N2O

NAAQS

Neonicotinoid

Neotropical

Bird

NEPA

G–6 Appendix G. Acronyms and Glossary
The ability of a drug or other agent to destroy or damage nervous tissue.

Nanogram

National Marine Fisheries Service

Nitrate

National Oceanic and Atmospheric Administration

Nitrogen oxide

No observable effect concentration; the highest tested concentration of a 

toxicant at which no adverse effects are observed on the test organisms at 

a specific time of observation.

No observable effect level; the highest dose levels at which there are no 

observable differences between the test and control populations.

Notice of Intent

O

Nitrogen dioxide

Ozone 

Office of Ocean and Coastal Resource Management

A sudden increase in numbers of a harmful organism.

To lay eggs.

P

A substance, including insecticides and herbicides, used for destroying 

insects or other organisms.

The ability of a substance to allow another substance to pass through it, 

especially the ability of a porous rock, sediment, or soil to transmit fluid 

through pores and cracks.

Particulate matter

NOAA

NOx

ng

NOI

NOEL

NOEC

Neurotoxicity

NMFS

NO3

O2

O3

OCRM

Pesticide

PM

Oviposit/

Oviposition

Outbreak

Permeability

Appendix G. Acronyms and Glossary G–7
Particulate matter that is less than 2.5 micrometers

Particulate matter that is between 2.5 and 10 micrometers

An insect or other organism that carries pollen from one flower to another.

Personal protective equipment

Parts per million

Plant Protection and Quarantine

A preventative measure.

An insect in its inactive immature form between larva and adult.

A larva becoming a pupa.

Q

A geographic area from which movement of regulated articles is restricted 

in order to prevent or reduce the human-assisted spread of a pest. APHIS 

establishes regulations that define the boundaries of quarantined areas. 

(Regulations for the ALB quarantined areas are located at 7 CFR § 

301.51-3.)

R

 Articles that can harbor life stages of ALB. The regulated articles listed 

under the ALB quarantine (7 CFR § 301.51) include the beetle and all its 

life stages; firewood (all hardwood species, not restricted to ALB-host 

trees); green lumber, and other living, dead, cut, or fallen material, 

including nursery stock, logs, stumps, roots, branches, and debris from 

ALB-host trees of 1⁄2 inch or more in diameter.

Chronic reference dose; the term preferred by EPA to express acceptable 

daily intake for humans; an estimate (with uncertainty spanning perhaps 

an order of magnitude) of a daily exposure to the human population, 

including sensitive subgroups, that is likely to be without an appreciable 

risk of deleterious effects during a lifetime. 

Of or relating to wetlands adjacent to rivers and streams.

PM2.5

PM10

PPE

PPQ

Pollinator

ppm

Prophylactic

Pupa

Pupate

RfD

Quarantined

Area/

Quarantine

Regulated

Articles

Riparian

G–8 Appendix G. Acronyms and Glossary
S

The saltiness or dissolved salt content.

An early and open process for determining the scope of issues to be 

addressed, and for identifying the significant issues related to a proposed 

action.

Matter that settles to the bottom of a liquid.

State Historic Preservation Office

The growing and cultivation of trees.

State implementation plan 

Sterile insect technique

Stream management zone

Sulfur dioxide

Sulfate

Sulfur oxides 

All the organisms that spend a significant portion of their life cycle within 

a soil profile, or at the soil-litter interface.

The process in which a stress applied to a soil causes densification as air is 

displaced from the pores between the soil grains.

Removal of topsoil faster than the soil forming processes can replace it, 

due to natural, animal, and human activity.

Not sufficient to cause death.

An outlying part of a city or town; a smaller community adjacent to or 

within commuting distance of a city.

An insecticide that is absorbed by the plant and moved throughout its 

tissues. 

SHPO

SIP

Scoping

Systemic 

Insecticide

Salinity

Sediment

Silviculture

SIT

SMZ

SO2

SO4

SOX

Soil Biota

Soil Erosion

Sublethal

Soil Compaction

Suburb/

Suburban

Appendix G. Acronyms and Glossary G–9
T

Threatened and endangered species

Triethylamine salt

An agent or factor that causes malformation of an embryo.

Of, on, or relating to the earth.

U

A layer of vegetation beneath the main canopy of a forest.

Of, pertaining to, or designating a city or town; or living in a city. 

United States Code

United State Department of Agriculture

Ultraviolet

V

An animal with a backbone or spinal column, including mammals, birds, 

reptiles, amphibians, and fishes.

Volatile organic compound

Cause a substance to evaporate or disperse in vapor.

W 

Wood packaging material

T&E Species

TEA

U.S.C.

USDA

VOC

WPM

Volatilize

UV

Urban

Understory

Teratogen/

Teratogenic

Vertebrate

Terrestrial

G–10 Appendix G. Acronyms and Glossary
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H–14 Appendix H. References
Appendix I. Distribution List

Phillip M. Baldauf, Project Manager

USDA–APHIS– PPQ 

1761 State Route 125, Suite A

Amelia, OH 45102

phillip.m.baldauf@aphis.usda.gov

Kermit Beckworth

Bethel, OH 

John Burch, State Plant Health Director

USDA–APHIS–PPQ

8995 East Main Street

Reynoldsburg, OH 43068

John.M.Burch@aphis.usda.gov

Faith Campbell

The Nature Conservancy

Arlington, VA 22203-1606

Tina Clary

Bethel, OH 45106

Lee Corte-Real, Director

Division of Crop and Pest Services 

MA Department of Agricultural Resources

251 Causeway Street, Suite 500

Boston, MA 02114–2151

lee.corte-real@state.ma.us

Carol DiSalvo

IPM Coordinator

NPS Servicewide 

carol_disalvo@nps.gov

Troy Evans

Kodak, TN 37764

http://www.springwildflowerpilgrimage.org/

Steve Garske

Policy Analyst/Attorney

Great Lakes Indian Fish & Wildlife 

Comm.

72682 Maple Lane

P.O. Box 9

Odanah, WI 54861

steveg@glifwc.org

Michael A. Girard

Executive Director 

North American Maple Syrup Council 

Simsbury, CT 06070

mgirard@simscroft.com

www.northamericanmaple.org

Joseph P. Gittleman, Project Manager

ALB Eradication Program, New York 

320–01 Merrick Rd

Amityville, NY 11701

Joe.P.Gittleman@aphis.usda.gov

Ken Gooch, Forest Health Program 

Director

Massachusetts Bureau of Forestry

51 Military Road

Amherst, MA 01002

ken.gooch@massmail.ma.us

Matthew Gordon 

c/o Vermont Maple Sugar Makers' Assn. 

Waterbury Center, VT 05676

Email: mgordon@vermontmaple.org

Kathleen Gough

c/o Tate Township Hall

3001 SR 125

Bethel, OH 45106–9454

Steve Hobart

Blanchard Twp, ME 04406

Appendix I. Distribution List I–1
Patricia Hornak

Bethel, OH 45106

Ellie Irons, Program Manager

Commonwealth of Virginia

Department of Environmental Quality

P.O. Box 1105 

Richmond, VA 23218

www.deq.virginia.gov

George Jibilian 

314 Peterson St.

Fort Collins, CO 80524

George@multigrain.com

Dan Kenny, State Plant Regulatory Official

Plant Pest Control Section

Division of Plant Industry

Ohio Dept. of Agriculture

8995 East Main St. 

Reynoldsburg, OH 43068

dkenny@agri.ohio.gov

Elizabeth A. Knott

9 Hillcroft Ave.

Worcester, MA 01606

Lorraine Koepfle

Tecumseh, MI 49286

David Lance, Acting Director

USDA-APHIS-PPQ CPHST Otis 

Laboratory

1398 W Truck Rd.

Buzzards Bay, MA 02542

david.r.lance@aphis.usda.gov

Elaine Leslie

National Park Service

Biological Resource Management Division 

1201 Oakridge Drive, Suite 200 

Fort Collins, CO 80525

Christopher Logue, Director

Division of Plant Industry

New York Dept. of Agriculture and Markets

10 B Airline Drive

Albany, NY 12235–0001

Christopher.Logue@agriculture.ny.gov

Joan Mahoney

Division of Plant Industry

New York Dept. of Agriculture and Markets

10 B Airline Drive

Albany, NY 1223–0001

joan.mahoney@agriculture.ny.gov

Antony Massop, Acting Project Manager

ALB Eradication Program

151 West Boylston Dr.

Worcester, MA 01606

antony.j.massop@aphis.usda.gov

Barry Matthews

Commonwealth of Virginia / Dept of Health

Madison Building

109 Governor Street, 6th Floor

Richmond, VA 23219

www.vdh.virginia.gov

Dennis Meguire

4922 State Route 222

Batavia, OH 45103

Jocelyn Millar

Department of Entomology

University of California 

Riverside, CA 92521

jocelyn.millar@ucr.edu

Dr. Timothy Perkins 

Professor & Director

Proctor Maple Research Center

University of Vermont 

Timothy.Perkins@uvm.edu

Appendix I. Distribution List I-2
Winton Pitcoff

Massachusetts Maple Producers Assoc.

Plainfield, MA 01070

info@massmaple.org

Jean Public 

Flemington, NJ 08822

Robyn Rose, PhD

National Program Manager

USDA, APHIS, PPQ

4700 River Road, Unit 26

Riverdale, MD 20737

robyn.i.rose@aphis.usda.gov

Ronald E. Rothhaas, Jr.

P.O. Box 11094 

Cincinnati, OH 45211

Josie Ryan, National Operations Manager

ALB Eradication Program

USDA, APHIS, PPQ

320 Merrick Rd

Amityville, NY 11701

josie.k.ryan@aphis.usda.gov

Rhonda Santos 

Public Information Officer

151 West Boylston Drive

Worcester, MA 01606

rhonda.J.Santos@aphis.usda.gov

Branislav Simic 

Acting State Plant Health Director

97 Barnes Rd., Unit 200

Wallingford, CT 06492

brani slav.v.simic@aphis.usda.gov

Glenn Taylor

Great Smoky Mountains National Park 

107Park Headquarters Road 

Gatlinburg, TN 37738

glenn_taylor@nps.gov

Roy Unversaw 

21444 Woodville Road 

Blanchester, OH 45107

Wendy Walsh

927 N. Main Street, Bld. D

FWS – NJ Field Office

Ecological Services

Pleasantville, New Jersey 08232

http://www.fws.gov/northeast/njfieldoffice/

Malfalda Weldon

Acting NY State Plant Health Director

USDA–APHIS–PPQ 

Penbrooke Dr., Suite 14 

Penfield, NY 14526

malfalda.weldon@aphis.usda.gov

Appendix I. Distribution List I–3
Appendix J. Index

A

Adaptive management, 24, 85

Additional methods development and research, 21

AFFECTED ENVIRONMENT, 33

Affected Biological Organisms, 43 

Affected Economic, Social, and Cultural Factors, 

47

Affected Forest Communities, 33 

Affected Soil, 38

Affected Water Resources, 35

Air, 40, 64, 72, 76, 83

ALB

ALB host species and soil quality, 39 

Dispersal and Spread, 4

Economic impacts of ALB in the United States, 7

Existing and projected ecological impacts in the 

United States and elsewhere, 9 

Geographic distribution, 6 

History of actions against ALB, 10 

Hosts, 4 

Life cycle, 2

ALTERNATIVES, 19

Alternatives considered but not included in this 

EIS, 31 

Other Integrated Pest Management/ Suppression 

Strategies, 31 

Use of other chemical control agents, 31

Alternatives evaluated in this EIS, 23 

Quarantine, 19

Survey, 20-23

Applicable environmental statutes, 91

Authority to act, 1

B

Bald and Golden Eagle Protection Act, 95

Biological control, 31

C

Consultations, 16

Cultural factors, 53

Cumulative impacts, 85

D

Decision framework, 14

Description of ALB, 2-7

E

Ecological resources, 58, 66, 73, 76, 84

Economic impacts of ALB in the U.S., 7

Economic, social, and cultural resources, 60, 68, 73, 

80, 84

Endangered Species Act, 91

ENVIRONMENAL CONSEQUENCES, 55

Program Alternatives, 55

Special Programmatic Considerations, 93 

Environmental resources, 64, 71, 75

Executive Order 12898, 97

Executive Order 13175, 97

Executive Order 13186, 98

EXECUTIVE SUMMARY, v

F

Federal and State Regulations and Statutes, 98

Forest resources, 63, 71, 74, 83

Full Host Removal, 28, 71

G

H

Herbicide use, 66, 70

Human health, 62, 69, 74, 81, 85

I

Imidacloprid, 14-15, 29-31, 74-84, 88-90, 97, 100-

101

Infested tree removals and insecticide treatment of 

high-risk host trees, 74

Insecticide treatment, 29

Insecticide/herbicide use, 77, 81

Integrated Approach (Preferred alternative), 30, 83

Interactions of soils with water quality, 37

Irreversible and Irretrievable Commitment of 

Resources, 101

J

K

L

M

Maple syrup, 50

Market factors, 47

Migratory Bird Treaty Act, 95

Mitigation and risk reduction, 98

N

NEPA requirements, 16

Appendix J. Index J-1
No action, 26, 51

Non-market factors, 51

O

P

Pheromones (insect), 32

Pollinators, 46

Preferred Alternative, 30

Program monitoring, 100

Public involvement, 11

PURPOSE OF and NEED FOR ACTION, 1

Background, 2

Consultations, 16

Decision Framework, 14

Public Involvement, 11

Scope of This Document and NEPA Requirements, 16

Q

Quarantine, 19

R

Regulatory treatments, 32

Removal of infested trees, 26, 63

S

Scope of document and NEPA Requirements, 16

Social factors, 52

Soil, 66, 72, 76, 84

Soil Erosion, 40

Soil types of the United States, 38

Stakeholder issues, 12

Sterile insect technique, 32

T

Timber, 47

Triclopyr, 27, 66-67, 70-71, 88

Tree nurseries, 51

U

V

W

Water, 64, 71, 75, 83

Water quality, 36

X

Y

Z

Appendix J. Index J-2