Hwy 46 FEIS Appendix 

441

Glossary

A

Advanced Regeneration - Small trees, usually 

less than 1 inch in diameter, which are growing 

under mature trees prior to planned harvest 

activities.

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. Used instead of "air pollution" 

when referring to programs.

Ambient Air Quality - defined under the Clean 

Air Act as the air quality outside of industrial 

site boundaries 

C

Canopy - The uppermost spreading branchy 

layer of a forest.

Canopy Cover - Canopy cover is a measure of 

the percentage of ground covered by a vertical 

projection of the tree canopy.

Canopy Closure - Canopy closure is the 

proportion of the sky hemisphere (measured 

from all angles) obscured by vegetation when 

viewed by a single point. Closure is affected by 

tree heights and canopy widths and takes into 

account light interception and other factors that 

influence microhabitat.

Chain – A standard measurement equal to 66

feet.

Cohort – A group of trees developing after a 

single disturbance, commonly consisting of trees 

of similar age, although it can include a 

considerable range of tree ages of seedling or 

sprout origin and trees that predate the 

disturbance.

Contiguous- In close proximity to or near.

Core Area - 0.5 mile (radius circle) around a 

known or predicted owl site, which delineates 

the area most heavily used during the nesting 

season for nesting, foraging and rearing young. 

Bingham and Noon (1997) defined the core area 

as that portion of a northern spotted owl home 

range that received disproportionately high use 

for nesting, roosting and access to prey; they 

suggested that 60-70% of owl reproducing 

season activity occurred in about 20% of the 

home range. Although Courtney et al. (2004:5-5) 

observed that core area sizes varied greatly 

among owls, Thrailkill (pers. com.) determined 

that Bingham and Noon 1997, Wagner and 

Anthony 1999, Franklin et al. 2000 and Irwin et 

al. 2004 collectively suggested a core area of 

about 500 acres.

Critical Habitat – The critical habitat 

designation is conducted by the U.S. Fish and 

Wildlife Service and is based on the current 

status and recent scientific research on northern 

spotted owl populations. Critical habitat was 

identified for specific areas within the 

geographical area occupied by the species at the 

time it was listed, on which are found those 

physical or biological features essential to the 

conservation of the species, and which may 

require special management considerations or 

protection. For the northern spotted owl, these 

features include particular forest types that are 

used or likely to be used by northern spotted 

owls for nesting, roosting, foraging, or 

dispersing habitat. In addition, the best available 

information was used to identify those areas that 

are otherwise determined to be essential to the 

conservation of the species. A habitat network 

was identified that meets the following criteria: • 

Ensures sufficient habitat to support stable, 

healthy populations across the range, and also 

within each of the 11 recovery units; • Ensures 

distribution of northern spotted owl populations 

across the range of habitat conditions used by 

the species; • Incorporates uncertainty, including 

potential effects of barred owls, climate change., 

and wildfire disturbance risk; and • Recognizes 

that these protections are meant to work in 
Glossary

442

concert with other recovery actions, such as 

barred owl management.

Cycle - As applied to uneven-aged management, 

it is the time interval between harvest entries. It 

should be noted that harvest entries in unevenaged management are to leave residual levels of 

growing stock which should not need treatment

for at least one cycle length.

D

Desirable Species - Any species of plant or 

animal which is considered to be compatible 

with meeting management goals and objectives.

Discounted Cost - Value of all cost associated 

with a project over its lifetime multiplied by a 

discount rate to determine the costs at today’s 

worth.

Discounted Revenue - Value of all revenue 

associated with a project over its lifetime 

multiplied by a discount rate to determine the 

value today.

Disturbance - Events that disrupt the stand 

structure and/or change resource availability or 

the physical environment (Oliver 1996).

Diameter Breast Height (dbh) – Diameter of a 

tree measured 4.5 feet up from the ground on the 

uphill side.

E

Early Seral - Plants which inhabit a disturbed 

site within the first few years subsequent to the

disturbance.

Early Seral Habitat – A forest structural 

condition that lasts 15-20 years after a human 

disturbance such as timber harvest, or natural 

disturbance such as wildfire. This structural 

condition can provide valuable wildlife habitat 

components including grasses, flowering forbs, 

hardwoods and dead wood habitat structures.

Emissions - A release of combustion gases and 

aerosols into the atmosphere.

F

Fire Behavior – The manner in which a fire 

reacts to the influences of fuel, weather, and 

topography.

Fire Intensity -The product of the available heat 

of combustion per unit of ground and the rate of 

spread of the fire, interpreted as the heat released 

per unit of time for each unit length of fire edge. 

The primary unit is Btu per second per foot 

(Btu/sec/ft) of fire front. Also, the rate of heat 

release per unit time per unit length of fire front. 

Numerically, it is the product of the heat yield, 

the quantity of fuel consumed in the fire front, 

and the rate of spread.

Fire Regime - A function of the historical 

frequency of fire and the degree of severity of 

those fires.

Fire Severity - Degree to which a site has been 

altered or disrupted by fire; loosely, a product of 

fire intensity and residence time.

Fuels - Vegetative matter, dead or alive, that 

burns in a fire. It is broadly characterized by the 

following categories:

• Surface or ground fuels are within a 

foot or so of the ground surface.

• Ladder fuels exist when you have a 

continuous vertical arrangement of 

fuel that allows fire to easily go 

from ground level into the tree 

canopy.

• Crown fuels are the tree limbs and 

leave that can burn with enough heat 

and/or wind.

• Live fuels are the green (live) herbs 

and shrubs.

Fuel Models - Simulated fuel complex for 

which all fuel descriptors required for the 

solution of a mathematical rate of spread model 

have been specified.
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443

H

Habitat Modification; Habitat Downgraded: 

Refers to silvicultural activities that change 

spotted owl suitable habitat to dispersal habitat

Habitat Removed: Refers to silvicultural 

activities that 1) Alter spotted owl suitable 

habitat such that it no longer supports nesting, 

roosting, foraging, and dispersal (i.e., suitable 

habitat becomes non-habitat after treatment) or 

2) Alter spotted owl dispersal habitat so that the 

habitat no longer supports dispersal (i.e., 

dispersal habitat becomes non-habitat after 

treatment).

Home Range - An estimated area for habitat use 

of a spotted owl pair. For the Oregon Cascades, 

this estimate is 1.2 miles (radius circle) around a 

known or predicted owl site (Thomas et al. 

1990, USDI et al. 2008).

Hyporheic Flow - Hyporheic flow is the mixing 

of shallow groundwater and surface beneath and 

alongside a stream bed.

I

Incidental Take (ESA) – Take that is incidental 

to, and not the purpose of, carrying out an 

otherwise lawful activity

Invasive Weed – see Noxious Weeds

K

Known Owl Site - A site that was or is occupied 

by a pair or resident single as defined by the 

survey protocol (1990-2012). The specific site 

location is determined by the unit biologist 

based on the best and/or most recent 

information. A known site may be determined to 

be inactive only in accordance with the

L

Ladder Fuels – Fuels that provide vertical 

continuity between the ground and tree crowns 

which create a pathway for a surface fire to 

move into the overstory tree crowns.

Local Road – A forest road that connects 

terminal facilities with forest collector, forest 

arterial or public highways. Usually forest local 

roads are single purpose transportation facilities. 

(FSH 7709.54, no longer in print)

M

Mechanical Treatment – Fuels reduction work 

completed by tracked or rubber tired equipment 

that may include grapple piling in slash 

concentrations, mastication, or any other 

mechanical device. 

Motor Vehicle Use Map (MVUM) – A map 

reflecting designated roads, trails and areas on 

an administrative unit or a Ranger District of the 

National Forest System. (36 CFR 261.2)

Multi-Cohort – a stand with two or more age 

classes or cohorts.

Munching - is the action of de-compacting the 

soil layers up to 18 - 24 inches deep by using 

excavator subsoiler attachments. The 

attachments are a regular excavator bucket (with 

thumb), grapple rakes (with thumb) or a 

modified bucket with added subsoiler shanks 

(and blades). The objective of the “munching” 

technique is breaking the soil layers down to 24 

inches in order to treat compaction in addition to 

applied slash above the area as an effective 

groundcover. With this technique, the soil layers 

would be de-compacted vertically and 

horizontally.

N

Nest Patch (or Stand) - 300 meters (radius 

circle) around a known or predicted owl site, 

where a spotted owl would be likely to select a 

nest tree. This is based on habitat usage of 

spotted owls within the Central Cascades Study 

Area, located on the Willamette National Forest.

Net Future Value - Difference in Discounted 

Revenue and Discounted Cost to evaluate if a 

project will have a positive or negative return on 

investment.

No Cut Buffer – Riparian buffer where no trees 

can be cut.
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444

No Harvest Buffer – Riparian buffer where 

trees may not be commercially cut and milled, 

but may be cut and felled for other purposes, 

such as streamside restoration treatment where 

specified and stream crossings or equipment 

access.

Noxious Weeds (Invasive species) - Nonnative plants listed by the State that generally 

have either economic or ecosystem impacts, or 

are poisonous to wildlife and/or livestock. They 

aggressively invade disturbed areas such as fires, 

road sides, and construction areas.

O

Obligate Predator - When the word is used as 

an adjective, obligate means "by necessity" (the 

antonym is facultative) and is used mainly in 

biology. An obligate predator is an organism 

whose survival is dependent on a diet consisting 

of animal flesh. In the case of aquatic insects 

these organisms would primarily eat other 

insects.

Off-Highway Vehicle (OHV) – Describes all 

those vehicles designed for off-highway use and 

which are classified as one of four classes of 

ATV in Oregon. (OHV Guide 2014)

P

Phytophagous - Feeding on plant material. This 

term is typically used when referring to insects.

Predicted Owl Site - An area able to support 

resident spotted owls (i.e. a potential breeding 

pair) as determined by the USDI et al. (2008) 

northern spotted owl occupancy template. This 

is used for determining effects to spotted owls 

where survey data are insufficient.

Pump Chance - A predetermined location 

where a water source can be accessed for filling 

engines or water tenders.

R

Remnant trees - Large to giant-diameter trees 

within younger-aged stands, that lived through 

past natural fire disturbances, or were retained 

after logging. Amounts and distribution of 

remnant trees within younger stands may be 

highly variable.

Road – A motor vehicle route over 50 inches 

wide, unless identified and managed as a trail. 

(36 CFR 212.1)

Road Decommissioning – Activities that result 

in the stabilization and restoration of unneeded 

roads to a more natural state. (36 CFR 212.1)

S

Salvage - Activity, usually removal or chipping, 

of material killed by a disturbance event such as 

insects, fire, wind, etc. Where possible, this 

material is used as some form of forest product 

of commercial value, such as firewood, pulp, 

and/or chips.

Seral Stages - Seral stage describes the phase of 

development of a plant community. Early seral 

species are those species you would expect to 

find on a site soon after a major disturbance, like 

fire. These are species such as pines, Douglasfir, snowbrush, fireweed, etc. They are generally 

shade intolerant species. Late seral are the 

species that can come in under a fully developed 

vegetative canopy, such as true firs, prince's 

pine, lichens, etc.

Silviculture -The theory and practice of 

directing forest establishment, composition, and 

growth for the production of forest resources to 

meet specific management objectives. The word 

is derived from the Latin word silva, which 

means "forest" and from cultura, which means 

"to develop and care for." So, it is the 

development and caring for the forest.

Silviculturist - One, who plans, assists in and 

supervises the implementation of silviculture 

projects. The Silviculturist determines 

(prescribes) the vegetative treatments necessary 

to meet the objectives for vegetation on a given 

site.

Site - A specific location where management 

activity is considered, planned, or operating.
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445

Site Potential - The specific ability of a site to 

grow vegetation. It includes the soil,

topographic, and climatic conditions that 

determine the resources available for growing 

vegetation.

Site Preparation - The removing or rearranging 

of vegetation or woody debris to meet specific 

management objectives. Most often it is used to 

describe the process(es) used to expose mineral 

soil areas suitable for planting or seeding 

desirable species of plants.

Slash - Debris resulting from such natural events 

as wind, fire, or snow breakage; or such human 

activities as road construction, logging, pruning, 

thinning, or brush cutting. It includes logs, 

chunks, bark, branches, stumps, and broken 

understory trees or brush.

Soundscape- Geographic region as defined by 

the audible sounds associated within it.

Spotted Owl Habitat Types – Suitable habitat

consists of forested stands used by spotted owls 

for nesting, roosting and foraging. Features that 

support nesting and roosting typically include a 

moderate to high canopy closure (60-90%); a 

multi-layered, multi-species canopy with large 

overstory trees (with dbh of greater than 30 

inches); a high incidence of large trees with 

various deformities (large cavities, broken tops, 

mistletoe infections, and other evidence of 

decadence); large snags; large accumulations of 

fallen trees and other woody debris on the 

ground; and sufficient open space below the 

canopy for spotted owls to fly. 

Foraging habitat generally has attributes similar 

to those of nesting and roosting habitat, but such 

habitat may not always support successfully 

nesting pairs (USFWS 2011c, p. A-10).

At a minimum, dispersal habitat consists of 

stands with adequate tree size and canopy 

closure to provide protection from avian 

predators and at least minimal foraging 

opportunities (USFWS 2011c, p. A-10). It 

consists of conifer and mixed mature coniferhardwood habitats with a canopy cover greater 

than or equal to 40% and conifer trees greater 

than or equal to 11 inches average diameter at 

breast height (dbh) with open space beneath the 

canopy to allow spotted owls to fly. Generally, 

spotted owls use younger stands to move 

between blocks of suitable habitat, roost, forage 

and survive until they can establish a nest 

territory. Juvenile owls also use dispersal habitat

to move from natal areas. Dispersal habitat thus 

includes habitat that will provide some roosting 

and foraging opportunities during the 

colonization phase of dispersal, but not at a scale 

that would support nesting pairs (in which case 

it would be classified as suitable habitat).

Suitable habitat can also function as dispersal 

habitat as it supports both territorial and 

dispersing spotted owls. However, in this 

document, dispersal habitat generally refers to 

stands that are 40-79 years old.

Stand - A group of trees of similar canopy 

structure, species composition, and/or size

growing on a continuous area. A stand is distinct 

from neighboring stands in structure, growing 

conditions, or management objectives. Stand age 

for this project is averaged and based on trees of 

commercial size which is seven inch dbh and 

greater.

Stand Density Index – SDI – A relative density 

measure based on the relationship between mean 

tree size and number of trees per unit area in a 

stand (Reineke 1933).

Stand Dynamics - The changes in forest stand 

structure with time, including stand behavior 

during and after disturbances (Oliver 1996).

Stand Structure - The physical and temporal 

distribution of trees and other plants in a stand 

(Oliver 1996).

Stream Classes - Class 1 and 2 = perennial fish

bearing streams; Class 3 = perennial non-fish 

bearing streams; Class 4 = intermittent, 

seasonally flowing streams.

Suppression - All the work of extinguishing or 

confining a fire beginning with its discovery.

T
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446

“Take” of ESA listed species - Take: to harass, 

harm, pursue, hunt, shoot, wound, kill, trap, 

capture, or collect or attempt to engage in any 

such conduct. Harm is further defined by 

USFWS to include significant habitat 

modification or degradation that results in death 

or injury to listed species by significantly 

impairing behavioral patterns such as breeding, 

feeding, or sheltering. Harass is defined by 

USFWS as actions that create the likelihood of 

injury to listed species to such an extent as to 

significantly disrupt normal behavior patterns 

which include, but are not limited to, breeding, 

feeding or sheltering.

Thinning - Any cutting or removal of 

vegetation (trees, brush, etc.) resulting in a 

reduction of competition for water, light, and/or 

nutrients between individual plants. 

• Commercial thinning refers to removing 

material that has an established dollar 

value on the open market and can be 

sold with at least a minimal net value 

sufficient to pay for the thinning

activity.

Torching - The burning of the foliage of a single 

tree or a small group of trees, from the bottom 

up. Also, single tree torching is one tree and 

group torching is more than one tree often a 

patch of multiple trees torching.

Treatment - A term used to broadly refer to the 

management actions made to meet management 

objectives. It may include thinning cutting of 

undesirable trees, prescribed fire, salvage, or any 

manipulation of the vegetative conditions. In 

addition, intentionally excluding a portion of a 

stand from harvest is a management action, or 

treatment.

Trees per Acre (TPA) – The number of trees on 

an acre of land.

U

Underburn - Using prescribed fire under the 

canopy of an existing stand of trees.

Undesirable Species - Any species of plant or 

animal which is NOT considered to be 

compatible with meeting management goals and 

objectives.

V

Vegetation Recovery- Period of time that 

allows for sufficient re-growth in harvested 

areas to make evidence of harvest activity 

largely unnoticeable to the casual observer.

W

Woody Debris - Dead pieces of woody 

vegetation such as stems, limbs, or leaves which 

are on a site.