CHAPTER 7 

GLOSSARY 

GLOSSARY

CHAPTER 7 

GLOSSARY 

A 

Absorption: The process by which a chemical or other 

substance is able to pass through body membranes 

and enter an organism. 

Active ingredient (a.i.): The chemical or biological 

component that kills or controls the target pest. 

Acute adverse effect level: The level at which a

substance can cause adverse effects within a short 

time of dosing or exposure. 

Acute effect: An adverse effect on any living organism 

in which symptoms develop rapidly and often

subside after the exposure stops. 

Acute toxicity: The quality or potential of a substance 

to cause injury or illness shortly after exposure to a 

relatively large dose. 

Adaptive management: A system of management

practices based on clearly identified outcomes, 

monitoring to determine if management actions are 

meeting outcomes, and if not, facilitating 

management changes that will best ensure that 

outcomes are met or reevaluated. 

Additive: A substance added to another in relatively 

small amounts to impart or improve desirable 

properties or suppress undesirable properties. 

Additive effect: A situation in which combined effects 

of exposure to two chemicals simultaneously is

equal to the sum of the effect of exposure to each 

chemical given alone. 

Adjuvant: A chemical that is added to the pesticide

formulation to enhance the toxicity of the active 

ingredient or to make the active ingredient easier to 

handle. 

Adsorption: 1) The adhesion of substances to the 

surface of solids or liquids. 2) The attraction of ions 

of compounds to the surface of solids or liquids. 

Adverse impact: An impact that causes harm or a 

negative result. 

Aerobic biodegradation: The breakdown of organic 

contaminants by microorganisms when oxygen is 

present. 

Air pollutant: Any substance in the air that could, if in

high enough concentration, harm humans, animals, 

vegetation, or material. Air pollutants may include 

almost any natural or artificial matter capable of 

being airborne in the form of solid particles, liquid 

droplets, gases, or a combination of these. 

Air quality: The composition of air with respect to 

quantities of pollution therein; used most frequently 

in connection with “standards” of maximum 

acceptable pollutant concentrations. 

Alien Species: Per Executive Order 13112, alien

species means, with respect to a particular 

ecosystem, any species, including its seed, eggs, 

spores, or other biological material capable of 

propagating that species, that is not native to that 

ecosystem. 

Allotment (grazing): Area designated for the use of a

certain number and kind of livestock for a 

prescribed period of time. 

Alluvium: General term for clay, silt, sand, or gravel

deposited in the bed of a stream during relatively 

recent geologic time as a result of stream action. 

Alternative: In an EIS, one of a number of possible 

options for responding to the purpose and need for 

action. 

Ambient air: Any unconfined portion of the 

atmosphere; open air and surrounding air. Often 

used interchangeably with “outdoor air.” 

 

Anadromous: A term used to describe fish that mature

in the sea and swim up freshwater rivers and 

streams to spawn. Salmon, steelhead, and sea-run

cutthroat trout are examples. 

BLM Vegetation Treatments Using Herbicides 7-1 June 2007 

Final Programmatic EIS 
GLOSSARY

Anaerobic biodegradation: The breakdown of organic 

contaminants by microorganisms when oxygen is 

not present. 

Animal Unit (AU): A standardized unit of 

measurement for range livestock that is equivalent

to one cow, one horse, five sheep, five goats, or 

four reindeer, all over 6 months of age. 

Animal Unit Month (AUM): The amount of feed or

forage required by one animal unit grazing on a 

pasture for 1 month. 

Annual (plant): A plant whose life cycle is completed

in 1 year or season. 

Antifoamer: A type of adjuvant added to a commercial

pesticide that prevents the formation of foam.

Aquatic: Growing, living in, frequenting, or taking 

place in water; used to indicate habitat, vegetation, 

or wildlife in freshwater. 

Aquifer: Rock or rock formations (often sand, gravel,

sandstone, or limestone) that contain or carry

groundwater and act as water reservoirs. 

Area of Critical Environmental Concern (ACEC):

An area within public lands that requires special

management attention to protect and prevent 

irreparable damage to important historic, cultural, 

or scenic values; fish and wildlife resources; other 

natural systems or processes; or to protect life or 

provide safety from natural hazards. 

Arid: A term applied to regions or climates where lack

of moisture severely limits growth and production

of vegetation. The limits of precipitation vary 

considerably according to temperature conditions. 

Attainment area: A geographic area that is in 

compliance with the National Ambient Air Quality 

Standards. An area considered to have air quality as 

good as or better than the National Ambient Air 

Quality Standards as defined in the Clean Air Act. 

B 

Binder: A material used to bind together two or more 

other materials in mixtures.

Bioaccumulation: The process of a plant or animal

selectively taking in or storing a persistent

substance. Over time, a higher concentration of the 

substance is found in the organism than in the

organism’s environment. 

Biodegradability: Susceptibility of a substance to 

decomposition by microorganisms; specifically, the

rate at which compounds may be chemically broken

down by bacteria and/or natural environmental

factors. 

Biodiversity: The variety of life and its processes, 

including all life forms from one-celled organisms 

to complex organisms such as insects, plants, birds,

reptiles, fish, other animals; and the processes, 

pathways, and cycles that link such organisms into

natural communities.

Biological Assessment (BA): A document prepared by 

or under the direction of a federal agency. A BA 

addresses federally-listed and species proposed for 

listing and designated and proposed critical habitat

that may be present in the action area, and evaluates 

the potential effects of the action on such species 

and habitat. 

Biological crust: Thin crust of living organisms on or

just below the soil surface; composed of lichens, 

mosses, algae, fungi, cyanobacteria, and bacteria. 

Boom (herbicide spray): A tubular metal device that 

conducts an herbicide mixture from a tank to a

series of spray nozzles. It may be mounted beneath 

a helicopter or a fixed-wing aircraft, or behind a

tractor or all-terrain vehicle. 

Brackish: Saline water whose salt concentration is 

between that of freshwater and seawater (ranging

from 0.5 to 30 parts per thousand).

Broadcast application: An application of an herbicide

that uniformly covers an entire area. 

Broad scale: A large, regional area, such as a river 

basin; typically a multi-state area. 

Buffer: A solution or liquid whose chemical makeup is 

such that it minimizes changes in pH when acids or 

bases are added to it. 

Buffer strip/zone: A strip of vegetation that is left or 

managed to reduce the impact that a treatment or

action on one area might have on another area. 

BLM Vegetation Treatments Using Herbicides 7-2 June 2007 

Final Programmatic EIS 
GLOSSARY

Bunchgrass: A grass having the characteristic growth

habit of forming a bunch; lacking stolons or 

rhizomes. 

C 

California Puff (CALPUFF): CALPUFF is an

advanced non-steady-state meteorological and air 

quality modeling system adopted by the U.S. 

Environmental Protection Agency as the preferred

model for assessing long range transport of 

pollutants and their impacts involving complex 

meteorological conditions. 

Carbon-14 dating: The use of the naturally occurring

isotope of carbon-14 in radiometric dating to 

determine the age of organic materials.

Carcinogen: A chemical capable of inducing cancer. 

Carnivore: An animal that feeds on other animals,

especially the flesh-eating mammals. 

Carrier: A non-pesticidal substance added to a 

commercial pesticide formulation to make it easier 

to handle or apply.

Carrying capacity: The maximum population of a

particular species that a particular region can 

support without hindering future generations’ 

ability to maintain the same population. 

Chaining: Vegetation removal that is accomplished by

hooking a large anchor chain between two

bulldozers; as the bulldozers move through the

vegetation, the vegetation is knocked to the ground. 

Chaining kills a large percentage of the vegetation, 

and is often followed a year or two later by burning 

and/or seeding. 

Chemical degradation: The breakdown of a chemical 

substance into simpler components through 

chemical reactions. 

Chronic adverse effect level: The level at which a

substance can cause adverse effects in which

symptoms recur frequently or develop slowly over 

a long period of time. 

Chronic exposure: Exposures that extend over the

average lifetime or for a significant fraction of the

lifetime of the individual. Chronic exposure studies 

are used to evaluate the carcinogenic potential of 

chemicals and other long-term health effects. 

Class I area: Under the 1977 Clean Air Act

amendments, all international parks, parks larger

than 6,000 acres, and national wilderness areas 

larger than 5,000 acres that existed on August 7,

1977. This class provides the most protection to

pristine lands by severely limiting the amount of

additional air pollution that can be added to these 

areas. 

Climate: The composite or generally prevailing weather 

conditions of a region throughout the year, 

averaged over a series of years. 

Coarse woody debris: Pieces of woody material

derived from tree limbs, boles, and roots in various 

stages of decay, generally having a diameter of at

least 3 inches and a length greater than 3 feet. 

Code of Federal Regulations (CFR): A codification of 

the general and permanent rules published in the 

Federal Register by the executive departments and

agencies of the federal government. 

Consultation: Exchange of information and interactive 

discussion; when the “C” in consultation is 

capitalized it refers to consultation mandated by 

statute or regulation that has prescribed parties, 

procedures, and timelines (e.g. Consultation under 

National Environmental Policy Act or Section 7 of 

the Endangered Species Act). 

Council on Environmental Quality (CEQ): An 

advisory council to the President of the United

States established by the National Environmental

Policy Act of 1969. It reviews federal programs for 

their effect on the environment, conducts 

environmental studies, and advises the President on

environmental matters. 

Countervailing: A type of cumulative impact where 

negative effects are compensated for by beneficial

effects. 

Cover: 1) Trees, shrubs, rocks, or other landscape 

features that allow an animal to partly or fully 

conceal itself. 2) The area of ground covered by 

plants of one or more species, usually expressed as 

a percent of the ground surface. 

BLM Vegetation Treatments Using Herbicides 7-3 June 2007 

Final Programmatic EIS 
GLOSSARY

Criteria: Data and information that are used to examine

or establish the relative degrees of desirability of 

alternatives or the degree to which a course of 

action meets an intended objective. 

Criteria pollutants: Air pollutants designated by the

U.S. Environmental Protection Agency as 

potentially harmful and for which ambient air

quality standards have been set to protect the public 

health and welfare. The criteria pollutants are 

carbon monoxide, sulfur dioxide, particulate matter,

nitrogen dioxide, ozone, hydrocarbons, and lead. 

Critical habitat: 1) Specific areas within the habitat a 

species occupies at the time it is listed under the 

Endangered Species Act that have physical or 

biological features (a) that are essential to the 

conservation of the species and (b) that may require 

special management considerations or protection; 

and 2) specific areas outside the habitat a species 

occupies at the time it is listed that the Secretary of 

the Interior determines are essential for species 

conservation. 

Cultural resources: Nonrenewable evidence of human

occupation or activity as seen in any area, site,

building, structure, artifact, ruin, object, work of art,

architecture, or natural feature, which was 

important in human history at the national, state, or 

local level. 

Cumulative effects: Impacts on the environment that

result from the incremental impact of an action 

when added to other past, present, and reasonably 

foreseeable future actions. Cumulative effects can 

result from individually minor, but collectively 

significant, actions taking place over a period of 

time. 

D 

Degradation: Physical or biological breakdown of a 

complex compound into simpler compounds. 

Density: The number of individuals per a given unit

area. 

Diluent: An inert diluting agent added to a commercial

pesticide formulation that decreases the viscosity of 

the formula. 

Dilution: The act of mixing or thinning, and therefore 

decreasing a certain strength or concentration. 

Direct effects: Impacts on the environment that are

caused by the action and occur at the same time and

place. 

Dispersant: A type of inert ingredient added to an

herbicide formulation that reduces the cohesive 

attraction between like particles. 

Dispersion: The act of distributing or separating into 

lower concentrations or less dense units. 

Disturbance: Refers to events that alter the structure,

composition, or function of terrestrial or aquatic

habitats. Natural disturbances include, among 

others, drought, floods, wind, fires, wildlife 

grazing, and insects and pathogens. Human-caused 

disturbances include actions such as timber 

harvest, livestock grazing, roads, and the introduction of exotic species. 

Dominant: A group of plants that by their collective 

size, mass, or number exerts a primary influence 

onto other ecosystem components. 

Dose: The amount of chemical administered or received 

by an organism, generally at a given point in time. 

Dose-response: Changes in toxicological responses of

an individual (such as alterations in severity of 

symptoms) or populations (such as alterations in 

incidence) that are related to changes in the dose of 

any given substance.

Draft Environmental Impact Statement (DEIS): The 

draft statement of the environmental effects of a 

major federal action which is required under 

Section 102 of the National Environmental Policy 

Act, and released to the public and other agencies 

for comment and review. 

Drift: That part of a sprayed chemical that is moved by

wind off a target site.

E 

Ecosystem: Includes all the organisms of an area, their 

environment, and the linkages or interactions 

among all of them; all parts of an ecosystem are 

interrelated. The fundamental unit in ecology, 

containing both organisms and abiotic

environments, each influencing the properties of the

other and both necessary for the maintenance of

life. 

BLM Vegetation Treatments Using Herbicides 7-4 June 2007 

Final Programmatic EIS 
GLOSSARY

Ecosystem-based management: The use of an

ecological approach to achieve multiple-use 

management of public lands by blending the needs 

of people and environmental values in such a way 

that public lands represent diverse, healthy,

productive, and sustainable ecosystems. 

Ecotone: A boundary or zone of transition between 

adjacent communities or environments, such as the

boundary between a forest and a meadow. Species 

present in an ecotone are intermixed subsets of the 

adjacent communities. 

Edge effect: The influence of two communities on

populations in their adjoining boundary zone or 

ecotone, affecting the composition and density of 

the populations in these bordering areas. 

Effect: Environmental change resulting from a

proposed action. Direct effects are caused by the 

action and occur at the same time and place, while 

indirect effects are caused by the action but are later 

in time or further removed in distance, although still 

reasonably foreseeable. Indirect effects may include 

growth-inducing effects and other effects related to 

induced changes in the pattern of land use, 

population density, or growth rate, and related

effects on air and water and other natural systems, 

including ecosystems. Effect and impact are 

synonymous as used in this document. 

Endangered species: Plant or animal species that are in

danger of extinction throughout all or a significant 

part of their range. 

Endemic species: Plants or animals that occur naturally 

in a certain region and whose distribution is

relatively limited to a particular locality. 

Environment: 1) The physical conditions that exist 

within an area (e.g., the area that will be affected by 

a proposed project), including land, air, water, 

minerals, flora, fauna, ambient noise, and objects of 

historical or aesthetic significance. 2) The sum of 

all external conditions that affect an organism or

community to influence its development or

existence. 

Environmental Assessment (EA): A concise public 

document, for which a federal agency is 

responsible, that serves to: 1) briefly provide 

sufficient evidence and analysis for determining 

whether to prepare an environmental impact

statement or a finding of no significant impact; 2)

aid an agency’s compliance with the National

Environmental Policy Act when no environmental

impact statement is necessary; and 3) facilitate

preparation of an environmental impact statement

when one is necessary. 

Environmental Impact Statement (EIS): A required

report for all federal actions that will lead to 

significant effects on the quality of the human 

environment. The report must be systematic and 

interdisciplinary, integrating the natural and social

sciences as well as the design arts in planning and

decision-making. The report must identify 1) the 

environmental impacts of the proposed action, 2) 

any adverse environmental effects which cannot be 

avoided should the proposal be implemented, 3) 

alternatives to the proposed action, 4) the 

relationship between short-term uses of human

environment and the maintenance and enhancement

of long-term productivity, and 5) any irreversible 

and irretrievable commitments of resources which 

would be involved in the proposed action should it 

be implemented. 

Epidemiology study: A study of human population or

human populations. In toxicology, a study which

examines the relationship of exposures to one or

more potentially toxic agent to adverse health 

effects in human populations. 

Eradication: Removal of all traces of a population or 

elimination of a population to the point where 

individuals are no longer detectable. 

Erosion: The wearing away of the land surface by 

running water, wind, ice, gravity, or other 

geological activities; can be accelerated or 

intensified by human activities that reduce the 

stability of slopes or soils. 

BLM Vegetation Treatments Using Herbicides 7-5 June 2007 

Final Programmatic EIS 
GLOSSARY

Essential Fish Habitat (EFH): As defined by Congress 

in the interim final rule (62FR 66551): “those 

waters and substrate necessary to fish for spawning,

breeding, feeding, or growth to maturity.” For the 

purpose of interpreting the definition of EFH 

habitat, “waters” include aquatic areas and their 

associated physical, chemical, and biological 

properties; “substrate” includes sediment

underlying the waters; “necessary” refers to the

habitat required to support a sustainable fishery and 

the managed species contribution to a healthy

ecosystem; and “spawning, breeding, feeding, or 

growth to maturity” covers all habitat types utilized 

by a species throughout its life cycle. 

Exotic species: Includes species introduced into an area 

that may have adapted to the area and compete with 

resident native (indigenous) species. 

F 

°F: Degrees Fahrenheit. 

Fate: The course of an applied herbicide in an

ecosystem or biological system, including 

metabolism, microbial degradation, leaching, and 

photodecomposition. 

Fauna: The vertebrate and invertebrate animals of the

area or region. 

Feasible: Capable of being accomplished in a 

successful manner within a reasonable period of 

time, taking into account economic, environmental, 

legal, social, and technological factors. 

Final Environmental Impact Statement (Final EIS):

A revision of the Draft Environmental Impact

Statement based on public and agency comments

on the draft. 

Fire dependent: An ecosystem evolving under periodic 

perturbations by fire and that consequently depends 

on periodic fires for normal ecosystem function. 

Fire intolerant: Species of plants that do not grow well

with or die from the effects of too much fire. 

Fire return interval: The average time between fires in

a given area. 

Fire tolerant: Species of plants that can withstand a 

certain frequency and intensity of fire. 

Fire use: The combination of prescribed fire and 

wildland fire use for resource benefit to meet

resource objectives. 

First order dermal absorption: Absorption of a 

material (herbicide) that occurs over 24 hours, 

taking into consideration the potential for some

herbicide to not be absorbed.

Fisheries habitat: Streams, lakes, and reservoirs that

support fish populations. 

Fishery: The act, process, occupation, or season of 

taking an aquatic species. 

Food Quality Protection Act (FQPA) safety factor:

The Food Quality Protection Act safety factor is

applied to pesticides that exhibit threshold effects to 

“take into account potential pre- and post-natal 

toxicity and completeness of the data with respect

to exposure and toxicity to infants and children.” 

The Act requires 1) an explicit determination that 

exposure tolerances are safe for children; 2) an 

additional safety factor of up to 10-fold, if 

necessary, be used to account for uncertainty in 

data relative to children (this is in addition to the 

current 100-fold safety factor which is already used

to account for the use of animals, versus humans, in

laboratory testing, and the variability in potential

adult response to pesticide exposure); and 3) an 

analysis of exposure risks to children that takes into

account the special sensitivity and exposure of

children to pesticides. 

Forage: Vegetation eaten by animals, especially

grazing and browsing animals. 

Forbs: Broad-leafed plants; includes plants that 

commonly are called weeds or wildflowers. 

Forestland: Land where the potential natural plant

community contains 10% or more tree canopy 

cover.

Formulation: The commercial mixture of both active 

and inactive (inert) ingredients. 

Fossilization: The process of fossilizing a plant or 

animal that existed in some earlier age; the process

of being turned to stone.

Fragmentation (habitat): The breaking-up of a habitat

or cover type into smaller, disconnected parcels. 

BLM Vegetation Treatments Using Herbicides 7-6 June 2007 

Final Programmatic EIS 
GLOSSARY

Fuel (fire): Dry, dead parts of trees, shrubs, and other 

vegetation that can burn readily.

G 

Gavage: Introduction of material in the stomach by a

tube. 

Groundwater: Subsurface water that is in the zone of 

saturation. The top surface of the groundwater is 

the “water table.” Source of water for wells, seeps,

and springs. 

H 

Habitat: The natural environment of a plant or animal,

including all biotic, climatic, and soil conditions, or 

other environmental influences affecting living

conditions. The place where an organism lives. 

Half life: The amount of time required for half of a 

compound to degrade. 

Hazardous fuels: Includes living and dead and 

decaying vegetation that form a special threat of 

ignition and resistance to control. 

Hazard quotient (HQ): The ratio of the estimated level

of exposure to a substance from a specific 

substance from a specific pesticide application to 

the reference dose (RfD) for that substance, or to 

some other index of acceptable exposure or

toxicity. A HQ less than or equal to 1 is presumed 

to indicate an acceptably low level of risk for that 

specific application. 

Herbaceous: Non-woody plants that include grasses, 

grass-like plants, and forbs. 

Herbicide: A chemical pesticide used to control, 

suppress, or kill vegetation, or severely interrupt 

normal growth processes. 

Herbicide resistance: Naturally-occurring heritable

characteristics that allow individual weeds to

survive and reproduce, producing a population,

over time, in which the majority of the plants of the 

weed species have the resistant characteristics. 

Herbivore: An animal that feeds on plants. 

Herd Management Areas (HMAs): Areas established

for wild and free-roaming horses and burros 

through the land use planning process. The Wild 

Free-roaming Horse and Burro Act of 1971 requires 

that wild free-roaming horses and burros be

considered for management where they were found

at the time Congress passed the Act. The BLM

initially identified 264 areas of use as herd

management areas. 

Home range: The area around an animal’s established

home that is visited during the animal’s normal

activities. 

Hydrologic cycle (water cycle): The ecological cycle 

that moves water from the air by precipitation to the 

earth and returns it to the atmosphere; includes 

evaporation, run-off, infiltration, percolation, 

storage, and transpiration. 

Hydrologic unit code (HUC): A hierarchical coding 

system developed by the U.S. Geological Survey to 

identify geographic boundaries of watersheds of

various sizes. 

Hydrolysis: Decomposition or alteration of a chemical 

substance by water. 

I 

Impermeable: Cannot be penetrated. 

Indigenous: Living or occurring naturally in an area;

native, endemic people, flora, or fauna. 

Indirect effects: Impacts that are caused by an action, 

but are later in time or farther removed in distance, 

although still reasonably foreseeable. 

Inert ingredient(s): Those ingredients that are added to

the commercial product (formulation) and are not

herbicidally active. 

Infiltration: The movement of water through soil pores 

and spaces. 

Insectivore: An organism that feeds mainly on insects. 

BLM Vegetation Treatments Using Herbicides 7-7 June 2007 

Final Programmatic EIS 
GLOSSARY

Integrated pest management (IPM): A long-standing,

science-based, decision-making process that

identifies and reduces risks from pests and pest 

management related strategies. It coordinates the 

use of pest biology, environmental information, and

available technology to prevent unacceptable levels 

of pest damage by the most economical means, 

while posing the least possible risk to people, 

property, resources, and the environment. IPM

provides an effective strategy for managing pests in

all arenas from developed agricultural, residential, 

and public areas to wild lands. IPM serves as an

umbrella to provide an effective, all encompassing, 

low-risk approach to protect resources and people 

from pests. BLM Departmental Manual 517

(Pesticides) defines integrated pest management as 

“a sustainable approach to managing pests by 

combining biological, cultural, physical, and

chemical tools in a way that minimizes economic,

health, and environmental risks.” 

Intermittent stream: A stream that flows only a certain 

times of the year when it receives water from other 

streams or from surface sources such as melting

snow. 

Invasive plants: Plants that 1) are not part of (if 

exotic), or are a minor component of (if native),

the original plant community or communities; 2)

have the potential to become a dominant or codominant species on the site if their future 

establishment and growth is not actively 

controlled by management interventions; or 3) are

classified as exotic or noxious plants under state or 

federal law. Species that become dominant for

only one to several years (e.g. short-term response

to drought or wildfire) are not invasive plants. 

Invasive species: Per Executive Order 13112, an

invasive species means an alien species whose

introduction does or is likely to cause economic or 

environmental harm or harm to human health. 

Invertebrate: Small animals that lack a backbone or 

spinal column. Spiders, insects, and worms are

examples of invertebrates. 

Irretrievable commitment: A term that applies to 

losses of production or commitment of renewable 

natural resources. For example, while an area is 

used as a ski area, some or all of the timber

production there is “irretrievably” lost. If the ski

area closes, timber production could resume;

therefore, the loss of timber production during the 

time the area is devoted to skiing is irretrievable, 

but not irreversible, because it is possible for timber

production to resume if the area is no longer used as

a ski area. 

Irreversible commitment: A term that applies to nonrenewable resources, such as minerals and

archaeological sites. Losses of these resources 

cannot be reversed. Irreversible effects can also

refer to the effects of actions on resources that can

be renewed only after a very long period of time, 

such as the loss of soil productivity. 

Issue: A matter of controversy, dispute, or general 

concern over resource management activities or 

land uses. 

J 

K 

Koc: Organic carbon-water partition coefficient. 

L 

Land management: The intentional process of 

planning, organizing, programming, coordinating,

directing, and controlling land use actions. 

Landscape: All the natural features such as grasslands,

hills, forest, and water, which distinguish one part

of the earth’s surface from another part; usually that

portion of land that the eye can comprehend in a 

single view, including all of its natural

characteristics.

Land use allocation: The assignment of a management

emphasis to particular land areas with the purpose 

of achieving the goals and objectives of some

specified use(s) (e.g., campgrounds, wilderness, 

logging, and mining). 

Large woody debris: Pieces of wood that are of a large 

enough size to affect stream channel morphology. 

LC50 (median lethal concentration): A calculated 

concentration of a chemical in air or water to 

which exposure for a specific length of time is 

expected to cause death in 50% of a defined 

experimental animal population. 

BLM Vegetation Treatments Using Herbicides 7-8 June 2007 

Final Programmatic EIS 
GLOSSARY

LD50 (median lethal dose): The dose of a chemical 

calculated to cause death in 50% of a defined 

experimental animal population over a specified 

observation period. The observation period is 

typically 14 days. 

Leaching: Usually refers to the movement of chemicals 

through the soil by water; may also refer to the 

movement of herbicides out of leaves, stems, or

roots into the air or soil. 

Level of concern (LOC): The concentration in media 

or some other estimate of exposure above which 

there may be effects. 

Lichens: Organisms made up of specific algae and

fungi, forming identifiable crusts on soil, rocks,

tree, bark, and other surfaces. Lichens are primary 

producers in ecosystems. They contribute living 

material and nutrients, enrich the soil and increase

soil moisture-holding capacity, and serve as food

sources for certain animals. Lichens are slow

growing and sensitive to chemical and physical

disturbances. 

Lifeways: The manner and means by which a group of

people lives; their way of life. Components

include language(s), subsistence strategies,

religion, economic structure, physical

mannerisms, and shared attitudes. 

 

Litter: The uppermost layer of organic debris on the

soil surface, which is essentially the freshly fallen 

or slightly decomposed vegetation material such

as stems, leaves, twigs, and fruits. 

Long term: Generally refers to a period longer than 

10 years. 

Lowest observed adverse effect level (LOAEL): The 

lowest dose of a chemical in a study, or group of 

studies, that produces statistically or biologically

significant increases in frequency or severity of 

adverse effects between the exposed and control

populations. 

Lymph: A clear water fluid containing white blood

cells. Lymph circulates throughout the lymphatic

system, removing bacteria and certain proteins 

from body tissue. It also is responsible for

transporting fat from the small intestine and 

supplying mature lymphocytes to the blood. 

Lymphatic: Pertaining to lymph, a lymph vessel, or a 

lymph node. 

M 

Macrophytes: Terrestrial or aquatic plants that are

large enough to be seen without the aid of a 

microscope. 

Material safety data sheet (MSDS): A compilation

of information required under the Occupational 

Safety and Health Administration Communication

Standard on the identity of hazardous chemicals,

health and physical hazards, exposure limits, and 

precautions. 

Memorandum of Understanding (MOU): Documents 

an agreement reached among agencies. 

Microbial degradation: The breakdown of a chemical

substance into simpler components by bacteria or 

other microorganisms. 

Microbiotic crust: See biological crust. 

Minimize: Apply best available technology, 

management practices, and scientific knowledge to 

reduce the magnitude, extent, and/or duration of 

impacts. 

Minimum tool rule: Apply only the minimum-impact

policy, device, force, regulation, instrument, or 

practice to bring about a desired result. 

Mitigation: Steps taken to: 1) avoid an impact

altogether by not taking a certain action or parts of

an action; 2) minimize an impact by limiting the 

degree or magnitude of the action and its 

implementation; 3) rectify an impact by repairing, 

rehabilitating, or restoring the affected

environment; 4) reduce or eliminate an impact over

time by preserving and maintaining operations 

during the life of the action; and, 5) compensate for 

an impact by replacing or providing substitute 

resources or environments (40 CFR Part 1508.20). 

Mitigation measures: Means taken to avoid, 

compensate for, rectify, or reduce the potential

adverse impact of an action. 

Monitoring: The orderly collection, analysis, and 

interpretation of resource data to evaluate progress 

toward meeting management objectives. 

BLM Vegetation Treatments Using Herbicides 7-9 June 2007 

Final Programmatic EIS 
GLOSSARY

Multiple uses: A combination of balanced and diverse 

resource uses that takes into account the long-term 

needs of future generations for renewable and

nonrenewable resources. These may include 

recreation, range, timber, minerals, watershed, 

wildlife, and fish, along with natural scenic, 

scientific, and historical values. 

N 

National Ambient Air Quality Standards (NAAQS):

Standards set by the U.S. Environmental Protection

Agency for the maximum levels of pollutants that

can exist in the outdoor air without unacceptable

effects on human health or the public welfare.

National Back Country Byways: A program

developed by the BLM to complement the National 

Scenic Byway program. The BLM’s Byways show

enthusiasts the best the West has to offer—from 

waterfalls to geology sculpted by volcanoes, 

glaciers, and rivers. Back Country Byways vary

from narrow, graded roads, passable only during a 

few months of the year, to two-lane paved 

highways providing year-round access. 

National Conservation Areas: Areas designated by 

Congress so that present and future generations of 

Americans can benefit from the conservation, 

protection, enhancement, use, and management of

these areas by enjoying their natural, recreational, 

cultural, wildlife, aquatic, archeological,

paleontological, historical, educational, and/or 

scientific resources and values. 

National Environmental Policy Act (NEPA): An act

of Congress passed in 1969, declaring a national

policy to encourage productive and enjoyable 

harmony between people and the environment, to

promote efforts that will prevent or eliminate

damage to the environment and the biosphere and 

stimulate the health and welfare of people, and to 

enrich the understanding of the ecological systems

and natural resources important to the nation, 

among other purposes. 

National Historic Trails: Trails established to identify 

and protect historic routes; they follow as closely as 

possible the original trails or routes of travel of 

national historic significance. 

National Landscape Conservation System (NLCS): 

A single system that encompasses some of the

BLM’s premier land designations. By putting these 

lands into an organized system, the BLM hopes to

increase public awareness of these areas’ scientific,

cultural, educational, ecological, and other values. 

National Monument: An area designated to protect 

objects of scientific and historic interest by public 

proclamation of the President under the Antiquities

Act of 1906, or by the Congress for historic

landmarks, historic and prehistoric structures, or

other objects of historic or scientific interest 

situated upon the public lands; designation also 

provides for the management of these features and

values. 

National Recreation Area: An area designated by 

Congress to assure the conservation and protection 

of natural, scenic, historic, pastoral, and fish and 

wildlife values and to provide for the enhancement

of recreational values. 

National Recreation Trails: Trails established 

administratively by the Secretary of the Interior to 

provide for a variety of outdoor recreation uses in

or reasonably close to urban areas. They often serve 

as connecting links between the National Historic

Trails and National Scenic Trails. 

National Scenic Areas: Refers to the one national 

scenic area managed by the BLM: The Santa Rosa 

Mountains National Scenic Area in California, 

which encompasses approximately 101,000 acres. 

This area was designated by the Secretary of the 

Interior in 1990 to provide for the conservation, 

protection, and enhancement of scenic, recreation, 

and pastoral values. 

National Scenic Trails: Trails established by an Act of

Congress that are intended to provide for maximum 

outdoor recreation potential and for the 

conservation and enjoyment of nationally

significant scenic, historical, natural, and cultural

qualities of the areas through which these trails

pass. National Scenic Trails may be located to 

represent desert, marsh, grassland, mountain, 

canyon, river, forest, and other areas, as well as

land forms that exhibit significant characteristics of 

the physiographic regions of the nation. 

BLM Vegetation Treatments Using Herbicides 7-10 June 2007 

Final Programmatic EIS 
GLOSSARY

National Wild and Scenic Rivers: Rivers designated

in the National Wild and Scenic Rivers System that

are classified in one of three categories, depending

on the extent of development and accessibility 

along each section. In addition to being free

flowing, these rivers and their immediate 

environments must possess at least one 

outstandingly remarkable value: scenic, 

recreational, geologic, fish and wildlife, historical, 

cultural, or other similar values. 

Native species: Species that historically occurred or

currently occur in a particular ecosystem and were

not introduced. 

Natural community: An assemblage of organisms

indigenous to an area that is characterized by

distinct combinations of species occupying a 

common ecological zone and interacting with one 

another. 

Natural resources: Water, soil, plants and animals, 

nutrients, and other resources produced by the 

earth’s natural processes. 

Neurotoxicity: Materials that affect nerve cells and 

may produce muscular, emotional, or behavioral

abnormalities, impaired or abnormal motion, and

other physiologic changes. 

Neutralizer: A type of inert ingredient added to an

herbicide that modifies the effect of, or counteracts 

the properties of, something within the herbicide or 

spray solution.

No action alternative: The most likely condition to

exist in the future if current management direction 

were to continue unchanged.

No observed adverse effect level (NOAEL): The 

exposure level at which there are no statistically or 

biological significant differences in the frequency

or severity of any adverse effect in the exposed or 

control populations. 

No observed effect level (NOEL): Exposure level at 

which there are no statistically or biological

significant differences in the frequency or severity

of any effect in the exposed or control

populations. 

Non-selective herbicide: An herbicide that is generally 

toxic to plants without regard to species. 

Non-target: Any plant, animal, or organism that a 

method of application is not aimed at, but may 

accidentally be injured by the application. 

Noxious weed: A plant species designated by federal or

state law as generally possessing one or more of the 

following characteristics: aggressive and difficult to 

manage; parasitic; a carrier or host of serious 

insects or disease; or non-native, new, or not 

common to the United States. 

Nutrient cycle: Ecological processes in which nutrients 

and elements such as carbon, phosphorous, 

nitrogen, and others, circulate among animals, 

plants, soils, and air. 

O 

Objective: A concise, time-specific statement of 

measurable planned results that respond to preestablished goals. An objective forms the basis for 

further planning to define the precise steps to be 

taken and the resources to be used to achieve 

identified goals. 

Omnivore: An animal that eats a combination of meat

and vegetation.

Oregon and California lands: Public lands in Western 

Oregon that were granted to the Oregon Central 

Railroad companies (later the Oregon and

California Railroad Company) to aid in the 

construction of railroads, but that were later 

forfeited and returned to the federal government by

revestment of title. 

Overgrazing: Continued heavy grazing which exceeds 

the recovery capacity of the plant community and

creates a deteriorated rangeland.

Overstory: The upper canopy layer. 

P 

Paleontological resources: A work of nature consisting

of or containing evidence of extinct multicellular 

beings and includes those works or classes of works 

of nature designated by the regulations as 

paleontological resources. 

Paleontology: A science dealing with the life of past

geological periods as known from fossil remains. 

BLM Vegetation Treatments Using Herbicides 7-11 June 2007 

Final Programmatic EIS 
GLOSSARY

Particulate matter (PM): A complex mixture 

consisting of varying combinations of dry solid

fragments, solid cores with liquid coatings, and 

small droplets of liquid. These tiny particles vary 

greatly in shape, size and chemical composition, 

and can be made up of many different materials 

such as metals, soot, soil, and dust. 

Particulates: Solid particles or liquid droplets 

suspended or carried in the air. 

Pathogen: An agent such as a fungus, virus, or

bacterium that causes disease. 

Payments in lieu of taxes: Payments made to counties 

by the BLM to mitigate for losses to counties

because public lands cannot be taxed. 

Per capita income: Total income divided by the total

population. 

Perennial: A plant that lives for 2 or more years. 

Permit: A revocable authorization to use public land 

for a specified purpose to for up to 3 years.

Persistence: Refers to the length of time a compound,

once introduced into the environment, stays there. 

Pest Infestation: 1) The occurrence of one or more 

pest species in an area or location where their 

numbers and impact are currently or potentially at

intolerable levels. 2) A sudden increase in 

destructiveness or population numbers of a pest 

species in a given area. 

Petroglyph: An image recorded on stone, usually by 

prehistoric peoples, by means of carving, pecking,

or otherwise incised on natural rock surfaces. 

Pictograph: A symbol that represents an object or a 

concept by illustration. 

pH: A measure of how acidic or alkaline (basic) a 

solution is on a scale of 0 to 14 with 0 being very 

acidic, 14 being very alkaline, and 7 being neutral. 

The abbreviation stands for the potential of 

hydrogen. 

Photodegradation: The photochemical transformation

of a molecule into lower molecular weight

fragments, usually in an oxidation process. This 

term is widely used in the destruction (oxidation) of 

pollutants by ultraviolet-based processes. 

Photolysis: Chemical decomposition induced by light 

or other radiant energy. 

Phytotoxicity: The ability of a material such as a

pesticide or fertilizer to cause injury to plants. 

Piscivore: Animal that feeds on fish. 

Plant community: A vegetation complex, unique in its

combination of plants, which occurs in particular 

locations under particular influences. A plant 

community is a reflection of integrated 

environmental influences on the site, such as soils,

temperature, elevation, solar radiation, slope aspect, 

and precipitation. 

Playas: Flat land surfaces underlain by fine sediment or 

evaporate minerals deposited from a shallow lake 

on the floor of a topographic depression. 

PM2.5: Fine particulates that measure 2.5 microns in

diameter or less.

PM10: Particulate matter that measures 10 microns in

diameter or less.

Population adjusted dose: The acute or chronic

reference dose (RfD) divided by the Food Quality 

Protection Act safety factor. 

Porosity: The ratio of the volume of void space in a 

material (e.g., sedimentary rock or sediments) to the 

volume of its mass. 

Predator: An organism that captures and feeds on parts 

or all of a living organism of another species. 

Preferred alternative: The alternative identified in an 

EIS that has been selected by the agency as the

most acceptable resolution to the problems 

identified in the purpose and need. 

Prescribed fire: A management ignited wildland fire 

that burns under specified conditions and in 

predetermined area, and that produces the fire 

behavior and fire characteristics required to attain

fire treatment and resource management objectives. 

BLM Vegetation Treatments Using Herbicides 7-12 June 2007 

Final Programmatic EIS 
GLOSSARY

Prescribed fire projects: Includes the BLM’s efforts to

utilize fire as a critical natural process to maintain

and restore ecosystems, rangeland, and forestlands, 

and to reduce the hazardous buildup of fuels that 

may threaten healthy lands and public safety. 

Prescribed grazing: The careful application of grazing 

or browsing prescriptions (i.e., specified grazing 

intensities, seasons, frequencies, livestock species, 

and degrees of selectivity) to achieve natural 

resource objectives. Livestock production is a 

secondary objective when using prescribed grazing

as a natural resource management tool. 

Prevention of Significant Deterioration (PSD): A 

U.S. Environmental Protection Agency program in

which state and/or federal permits are required in 

order to restrict emissions from new or modified

sources in places where air quality already meets or

exceeds primary and secondary ambient air quality 

standards. 

Productivity: The innate capacity of an environment to

support plant and animal life over time. Plant 

productivity is the rate of plant production within a 

given period of time. Soil productivity is the 

capacity of a soil to produce plant growth, due to 

the soil’s chemical, physical, and biological

properties. 

Programmatic EIS: An area-wide EIS that provides an 

overview when a large-scale plan is being prepared

for the management of federally-administered lands 

on a regional or multi-regional basis. 

Proper functioning condition: Riparian and wetland 

areas achieve proper functioning condition when 

adequate vegetation, landform, or large woody 

debris is present to dissipate stream energy 

associated with high water flows. This reduces 

erosion and improves water quality; filters 

sediment, captures bedload, and aids in floodplain

development; improves floodwater retention and 

groundwater recharge; develops root masses that

stabilize streambacks against cutting; develops 

diverse ponding and channel characteristics to

provide habitat and water depth, duration, and

temperature necessary for fish production, avian

breeding habitat, and other uses; and supports 

greater biodiversity.

Proposed action: A proposal by a federal agency to

authorize, recommend, or implement an action. 

Public domain lands: One category of public lands that

have never left federal ownership; also, lands in 

federal ownership that were obtained by the 

government in exchange for public domain lands or 

for timber on public domain lands. 

Public lands: Any land and interest in land owned by

the United States that are administered by the

Secretary of the Interior through the BLM, without

regard to how the United States acquired 

ownership, except for 1) lands located on the Outer 

Continental Shelf, and 2) lands held for the benefit 

of Indians, Aleuts, and Eskimos. Includes public 

domain and acquired lands. 

Public scoping: A process whereby the public is given

the opportunity to provide oral or written comments 

about the influence of a project on an individual, 

the community, and/or the environment. 

Q 

Qualitative: Traits or characteristics that relate to 

quality and cannot be readily measured with

numbers. 

Quantitative: Traits or characteristics that can be

measured with numbers. 

R 

Rangeland: Land on which the native vegetation is 

predominantly grasses, grass-like plants, forbs, or 

shrubs; not forests. 

Raptor: Bird of prey; includes eagles, hawks, falcons, 

and owls. 

Receptor: An ecological entity exposed to a stressor. 

Record of Decision (ROD): A document separate 

from, but associated with, an EIS, which states the

decision, identifies alternatives (specifying which

were environmentally preferable), and states 

whether all practicable means to avoid 

environmental harm from the alternative have been 

adopted, and if not, why not. 

Recovery plan: Identifies, justifies, and schedules the 

research and management actions necessary to

reverse the decline of a species and ensure its longterm survival. 

BLM Vegetation Treatments Using Herbicides 7-13 June 2007 

Final Programmatic EIS 
GLOSSARY

Reference dose (RfD): An estimate (with uncertainty 

spanning perhaps an order of magnitude) of a daily 

oral exposure to the human population (including

sensitive subgroups) that is likely to not result in an

appreciable risk of deleterious effects during a 

lifetime. It is derived from the no-observedadverse-effect-level, the lowest-observed-adverseeffect-level, or a benchmark dose. Uncertainty 

factors are generally applied when developing the 

reference dose to reflect the limitations of the data 

used. 

Registered herbicide: All herbicides sold or distributed

in the United States must be registered by the U.S. 

Environmental Protection Agency, based on 

scientific studies, showing that they can be used

without posing unreasonable risks to people or the

environment. 

Research Natural Areas: Special management areas 

designated either by Congress or by a public or 

private agency to preserve and protect typical or 

unusual ecological communities, associations, 

phenomena, characteristics, or natural features or 

processes for scientific and educational purposes. 

They are established and managed to protect 

ecological processes, conserve biological diversity,

and provide opportunities for observation for 

research and education. 

Resident fish: Fish that spend their entire life in 

freshwater (e.g., bull trout). 

Residue: The quantity of an herbicide or its metabolites 

remaining in or on soil, water, plants, animals, or 

surfaces. 

Resilience: 1) The ability of a system to respond to

disturbances. Resiliency is one of the properties 

that enable the system to persist in many

different states or successional stages. 2) In

human communities, refers to the ability of a

community to respond to externally induced 

changes such as larger economic forces. 

Resource Management Plan (RMP): Comprehensive 

land management planning document prepared by 

and for the BLM’s administered properties under 

requirements of the Federal Land Policy and

Management Act. Bureau of Land Management

lands in Alaska were exempted from this 

requirement. 

Restoration: Actions taken to modify an ecosystem to

achieve desired, healthy, and functioning conditions 

and processes. 

Revegetation: Establishing or re-establishing desirable 

plants on areas where desirable plants are absent or 

of inadequate density, by management alone

(natural revegetation) or by seeding or transplanting

(artificial revegetation). 

Rights-of-way (ROW): A permit or an easement that

authorizes the use of lands for certain specified 

purposes, such as the construction of forest access 

roads or a gas pipeline. 

Riparian: Occurring adjacent to streams and rivers and

directly influenced by water. A riparian community 

is characterized by certain types of vegetation, soils, 

hydrology, and fauna and requires free or unbound

water or conditions more moist than that normally 

found in the area. 

Risk: The likelihood that a given exposure to an item or

substance that presents a certain hazard will 

produce illness or injury. 

Risk assessment: The process of gathering data and

making assumptions to estimate short- and longterm harmful effects on human health or the

environment from particular products or activities. 

Runoff: That part of precipitation, as well as any other 

flow contributions, that appears in surface streams,

either perennial or intermittent. 

S 

Salmonids: Fishes of the family Salmonidae, including

salmon, trout, chars, whitefish, ciscoes, and 

grayling. 

Scoping: The process by which significant issues

relating to a proposal are identified for 

environmental analysis. Scoping includes eliciting 

public comment on the proposal, evaluating

concerns, and developing alternatives for 

consideration. 

Section 3: Lands administered under Section 3 of the 

Taylor Grazing Act. This section of the law 

provided for the lease of grazing district lands to 

landowners and homesteaders in or adjacent to the

reserves first and issuance of 1 to 10 year leases. 

BLM Vegetation Treatments Using Herbicides 7-14 June 2007 

Final Programmatic EIS 
GLOSSARY

Section 15: Lands administered under Section 15 of the 

Taylor Grazing Act. Under Section 15, public lands 

outside of grazing districts could be leased to

ranchers with contiguous property.

Sediments: Unweathered geologic materials generally 

laid down by or within waterbodies; the rocks, 

sand, mud, silt, and clay at the bottom and along the 

edge of lakes, streams, and oceans. 

Sedimentation: The process of forming or depositing 

sediment; letting solids settle out of wastewater by 

gravity during treatment. 

Selective herbicide: A chemical designed to affect only 

certain types of plants, leaving other plants 

unharmed.

Semi-arid: Moderately dry; region or climate where 

moisture is normally greater than under arid

conditions, but still limits the production of 

vegetation. 

Sensitive species: 1) Plant or animal species susceptible

or vulnerable to activity impacts or habitat

alterations. 2) Species that have appeared in the

Federal Register as proposed for classification or 

are under consideration for official listing as 

endangered or threatened species. 

Short-term impacts: Impacts occurring during project 

construction and operation, and normally ceasing

upon project closure and reclamation. For each 

resource the definition of short-term may vary. 

Significant: The description of an impact that exceeds a 

certain threshold level. Requires consideration of 

both context and intensity. The significance of an 

action must be analyzed in several contexts, such as 

society as a whole, and the affected region,

interests, and locality. Intensity refers to the

severity of impacts, which should weighted along

with the likelihood of its occurrence. 

Snag: A standing dead tree, usually larger than 5 feet

tall and 6 inches in diameter at breast height. 

Sociocultural: Of, relating to, or involving a

combination of social and cultural factors. 

Socioeconomic: Pertaining to, or signifying the 

combination or interaction of social and economic 

factors. 

Soil compaction: The compression of the soil profile 

from surface pressure, resulting in reduced air 

space, lower water holding capacity, and decreased

plant root penetrability. 

Soil horizon: A layer of soil material approximately

parallel to the land surface that differs from

adjacent genetically related layers in physical,

chemical, and biological properties. 

Southern Nevada Public Land Management Act: Act

that provides for the disposal of public land within a 

specific area in the Las Vegas Valley and creates a

special account into which 85% of the revenue 

generated by land sales or exchanges in the Las 

Vegas Valley is deposited. The remaining 15%

goes to state and local governments. 

Special status species: Refers to federally-listed

threatened, endangered, proposed, or candidate

species, and species managed as sensitive species 

by the BLM. 

Spot treatment: An application of an herbicide to a

small selected area as opposed to broadcast 

application. 

Stabilizer: A type of inert ingredient added to a

commercial pesticide that makes the mixture more 

stable. 

Stand: A group of trees in a specific area that is

sufficiently alike in composition, age, arrangement,

and condition so as to be distinguishable from the

forest in adjoining areas. 

Standard Operating Procedures (SOPs): Procedures 

that would be followed by the BLM to ensure those 

risks to human health and the environment from 

treatment actions were kept to a minimum.

Step-down: Refers to the process of applying broadscale science findings and land use decisions to

site-specific areas using a hierarchical approach of 

understanding current resource conditions, risks, 

and opportunities. 

Stressor: Any event or situation that precipitates a 

change. 

BLM Vegetation Treatments Using Herbicides 7-15 June 2007 

Final Programmatic EIS 
GLOSSARY

Subalpine: A terrestrial community that generally is 

found in harsher environments than the montane 

terrestrial community. Subalpine communities are 

generally colder than montane and support a unique 

clustering of wildlife species. 

Subchronic: The effects observed from doses that are

of intermediate duration, usually 90 days. 

Subsistence: Customary and traditional uses of wild

renewable resources (plants and animals) for food, 

shelter, fuel, clothing, tools, etc. 

Succession: A change in structure and composition of 

plant and animal communities over time. This 

change does not always occur in a predictable and 

orderly manner. Change can be a response to

random or chaotically occurring disturbances. 

Surfactant: A material that improves the emulsifying,

dispersing, spreading, wetting, or other surfacemodifying properties of liquids. 

Surrogate: A substitute or stand-in. 

Synergistic: A type of cumulative impact where total 

effect is greater than the sum of the effects taken 

independently. 

T 

Tank mixture: The mixture of two or more compatible

herbicides in a spray tank in order to apply them 

simultaneously. 

Target species: Plant species of competing vegetation 

that is controlled in favor of desired species. 

Teratogenic: Causing structural defects that affect the

development of an organism; causing birth

defects. 

Terrestrial: Of or relating to the earth, soil, or land;

inhabiting the earth or land. 

Threatened species: A plant or animal species likely to

become an endangered species throughout all or a 

significant portion of its range within the

foreseeable future. 

Threshold: A dose or exposure below which there is no

apparent or measurable adverse effect. 

Tier: In an EIS, refers to incorporating by reference the

analyses in an EIS or similar document of a broader 

scope. For example, BLM field offices could

prepare environmental assessments for local

projects that tier to this PEIS. 

Total suspended particles (TSP): A method of

monitoring airborne particulate matter by total

weight. 

Toxicity: A characteristic of a substance that makes it

poisonous. 

Toxicokinetics: The process of the uptake of potentially 

toxic substances by the body, the biotransformation

they undergo, the distribution of the substances and

their metabolites in the tissues, and the elimination

of the substances and their metabolites from the

body. 

Transpiration: Water loss from plants during 

photosynthesis. 

Tribe: Term used to designate any Indian tribe, band, 

nation, or other organized group or community 

(including any Alaska Native village or regional or 

village corporation as defined in or established 

pursuant to the Alaska Native Claims Settlement

Act) which is recognized as eligible for the special 

programs and services provided by the U.S. to

Indians because of their status as Indians. 

U 

Understory: Plants that grow beneath the canopy of 

other plants. Usually refers to grasses, forbs, and 

low shrubs under a tree or shrub canopy. 

Undesirable plants: Species classified as undesirable, 

noxious, harmful, exotic, injurious, or poisonous 

under state or federal law, but not including species 

listed as endangered by the Endangered Species 

Act, or species indigenous to the planning area. 

Upland: The portion of the landscape above the valley 

floor or stream. 

BLM Vegetation Treatments Using Herbicides 7-16 June 2007 

Final Programmatic EIS 
GLOSSARY

V 

Vascular plants: Plants that have specialized tissues 

which conduct nutrients, water, and sugars along 

with other specialized parts such as roots, stems,

and reproductive structures. Vascular plants include 

flowering plants, ferns, shrubs, grasses, and trees. 

Vertebrate: An animal with a backbone. Fishes, 

amphibians, reptiles, birds, and mammals are

vertebrates. 

Visual resources: The visible physical features of a

landscape. 

Volatilization: The conversion of a solid or liquid into 

a gas or vapor.

W 

Water quality: The interaction between various 

parameters that determines the usability or nonusability of water for on-site and downstream uses.

Major parameters that affect water quality include:

temperature, turbidity, suspended sediment, 

conductivity, dissolved oxygen, pH, specific ions, 

discharge, and fecal coliform. 

Watershed: The region draining into a river, river 

system, or body of water. 

Weed: A plant considered undesirable and that

interferes with management objectives for a given 

area at a given point in time. 

Wetlands: Those areas that are inundated or saturated

by surface water or groundwater at a frequency and 

duration sufficient to support, and that under 

normal circumstance do support, a prevalence of 

vegetation typically adapted for life in saturated soil 

conditions. Wetlands include habitats such as 

swamps, marshes, and bogs. 

Wilderness: Land designated by Congress as a 

component of the National Wilderness Preservation 

System. For an area to be considered for 

Wilderness designation it must be roadless and

possess the characteristics required by Section 2(c) 

of the Wilderness Act of 1964. These 

characteristics are: 1) naturalness - lands that are 

natural and primarily affected by the forces of 

nature; 2) roadless and having at least 5,000 acres 

of contiguous public lands; and 3) outstanding 

opportunities for solitude or primitive and

unconfined types of recreation. In addition, areas 

may contain “supplemental values,” consisting of 

ecological, geological, or other features of 

scientific, educational, scenic, or historical

importance. 

Wildfire: Unplanned human or naturally caused fires in 

wildlands. 

Wildland fires: Occur on wildlands, regardless of

ignition source, damages, or benefits, and include

wildfire and prescribed fire. 

Wildland fire use for resource benefit: A fire ignited 

by lightening but allowed to burn within specified

conditions of fuels, weather, and topography, to

achieve specific objectives. 

Wildland Urban Interface (WUI): An area where

structures and other human development

intermingle with undeveloped wildlands or 

vegetative fuels. 

Woodland: A forest in which the trees are often small, 

characteristically short-bolded relative to their 

crown depth, and forming only an open canopy

with the intervening area being occupied by lower

vegetation, commonly grass. 

X 

Xeric: Very dry region or climate; tolerating or adapted

to dry conditions. 

YZ 

BLM Vegetation Treatments Using Herbicides 7-17 June 2007 

Final Programmatic EIS