Glossary of Terms

Glossary of Terms

  • Browse
    The part of shrubs, woody vines and trees that are suitable for animal consumption.
  • Adaptive management
    A process for implementing management decisions that requires monitoring of actions and adjustment of decisions based on results. Adaptive management applies scientific principles and methods to improve management decisions incrementally as experience is gained and in response to new scientific findings and societal changes.
  • Woody debris
    Dead woody vegetation that enters a riparian-wetland area that is large enough to remain in place for a period of time and operate as a hydrological modifier.
  • Wildland urban interface
    The area or zone where residential development or other structures meet or intermingle with undeveloped areas.
  • Wetland
    Lands transitional between terrestrial and aquatic systems where the water table is at or near the surface, or land that is covered by shallow water.  For purposes of classification, wetlands must have at least one of the following attributes:  1) at least periodically, the land supports predominately hydrophytes; 2) the substrate is predominately undrained hydric soil; and 3)  the substrate Continue Reading
  • Uneven-aged
    Forest stand composed of an intermingling of trees that differ markedly in age. 
  • Understory
    The lower vegetation layers in a forest found beneath the forest canopy including grasses, forbs, sedges, succulents and shrubs; also referred to as rangeland vegetation.
  • Thinning
    The removal of undesirable trees for the purpose of improving forest growth and health. 
  • Sustainability
    The ability of an ecosystem to maintain ecological processes and functions, biological diversity and productivity over time.
  • Succession
    The directional and continuous pattern of colonization and extinction on a site by populations.
  • Stand
    A community of trees sufficiently uniform in composition, age, spatial arrangement, or condition, to be distinguished from other plant communities and be treated as one entity for the purposes of management. 
  • Spatially explicit
    A set of resource management tools that may include a Geographic Information System (GIS), Geographic Positioning System (GPS), digital camera or video camera that are used to document management activities and summarize data in meaningful was.  Spatially explicit technologies provide decision support to managers by integrating traditional forms of data capture into a GIS. 
  • Snags
    Standing dead trees.  Snags provide valuable habitat to numerous wildlife species.
  • Slash
    Tree branches and woody material generated by forest thinning operations.
  • Site index
    The average height of the dominant stand at a specified reference age (typically 100 years).  This is a measure of site productivity for a given species.
  • Silviculture
    The science and of art of cultivating forests by controlling or manipulating the establishment, composition and growth of trees. 
  • Seral
    A temporal and intermediate stage in the process of succession.
  • Sanitation cutting
    The removal of disease or insect infested trees from a stand.
  • Riparian
    A type of wetland that is a transitional area between permanently saturated wetlands and upland sites.  This transition area has vegetation or physical characteristics reflective of permanent surface or subsurface water influence.
  • Restoration
    The process of returning ecosystem patterns, processes or components to within the historical range of variability or other defined reference condition. 
  • Reference conditions
    Conditions that characterize ecosystem composition, structure, function and their variability.
  • Ratoon
    A sprout that grows from a root.
  • Rangeland
    Treeless or sparsely forested (<10% tree canopy cover) areas that are dominated by herbaceous or shrubby vegetation.  These areas are also called forest “openings”.
  • Prescribed burn
    The controlled application of fire to wildland fuels to produce the fire behavior and characteristics required to attain resource management objectives.
  • Potential natural community
    The biological community an area could support given adequate time for succession, the climax community.
  • Perennial stream
    A stream that flows continuously throughout the year.  Perennial streams are generally associated with a water table in the locations through which they flow.
  • Patch cut
    A silvicultural method where all trees in a localized area are harvested.  Patch size varies depending upon forest type and management goals but is typically 1 to 250 acres.
  • Noxious weed
    A plant that is exotic to a particular environment that is capable of displacing native plant communities through aggressive competition for resources and prolific regeneration. A species that has a potential to cause significant ecological or economical damage.
  • Native
    Plants, animals and materials that are indigenous to a site.
  • Mechanical control
    The use of physical practices to reduce the incidence of undesirable plants such as mowing, plowing or hand pulling.
  • Landing
    A temporary storage area for accumulated logs removed from a forest stand during forestry operations.
  • Ladder fuel
    Any combustible material that enables flames to proceed from the ground into tree canopies; typical ladder fuels include tall grasses and shrubs, small trees, low hanging tree branches and deadfall.
  • Invasive
    Alien species whose introduction and spread does or is likely to cause harm to the economy, the environment, or human health.
  • Intermittent stream
    A stream that flows only at certain times of the year when it receives water from springs or from some surface source such as snow in mountainous areas.  Intermittent streams flow continuously for at least 30 days a year.
  • Infiltration
    The downward movement of water into the immediate surface of soil or other material, as contrasted with percolation, which is the movement of water through soil layers.
  • Historical range of variability
    The range of spatial, structural, compositional and temporal characteristics of ecosystem elements during a period specified to represent “natural” conditions.
  • Heterogeneity
    Landscape diversity in the composition, size, shape and arrangement in time and space of landscape components that characterize ecological structure and function.
  • Herbaceous
    Not woody.
  • Headcut
    An erosional process moving upstream or upslope from the location of origin.
  • Habitat
    Conditions essential for wildlife or fish including sufficient water, food, space, shelter and reproductive needs.
  • Geographic Information System (GIS)
    GIS is a computer database and analytical tool designed to analyze geographic data.
  • Fuel load
    The oven dry weight of fuels in a given area, usually expressed in tons/acre.
  • Fuels
    Plants and woody vegetation (live or dead) that are capable of supporting combustion.
  • Fuelbreak
    A natural or constructed discontinuity in a fuel profile utilized to isolate, stop, or reduce the spread of fire.  Fuel breaks may also make retardant lines more effective and serve as control lines for fire suppression actions.  Fuel breaks in the WUI are designed to limit the spread and intensity of crown fire activity.
  • Forage
    Browse and herbage that is available for grazing animals.
  • Fire suppression
    A coordinated effort to control or extinguish wildland fires.  A resource management policy initiated in the early 1900’s by the U.S. Forest Service in response to widespread wildland fires burned hundreds of thousands of acres of public land.  This policy, which was initiated to preserve forest lands, has been revised in recent decades as research has shown that fire is Continue Reading
  • Fire intensity
    The rate of heat release/unit time/length of the fire front (in BTUs/second/foot).  Fire intensity depends on the rate of spread, the heat of combustion, and the total amount of fuel consumed. 
  • Fire interval
    The amount of time between recurrent wildland fires.
  • Exotic
    Plants, animals, or materials that are not native to a site.
  • Even-aged
    Forest stand composed of trees of the same or approximately the same age.
  • Erosion
    The wearing away of the land surface by detachment and movement of soil and rock fragments by water, wind, or other geological agents.
  • Ephemeral stream
    A stream that flows in direct response to precipitation and whose channel is at all times above the water table.  Ephemeral streams flow for less than 30 days a year.
  • Ecosystem management
    A concept of natural resource management in which human activities are considered within the context of ecological, societal and economic interactions within a defined area over both the short term and long term.  A major goal of ecosystem management is to sustain the ecosystem to meet ecological and human needs into the future: sustainability.
  • Ecosystem function
    The processes through which the constituent living and non-living elements of an ecosystem change and interact, including biogeochemical processes and succession.
  • Ecosystem
    Living organisms interacting with each other and their physical environment, usually described as an area that is meaningful to address these relationships.
  • Downed fuels
    The accumulation of dead woody material on the forest floor that has been severed from its source of growth; materials that serve as fuel for wildfires. 
  • Dog hair stands
    Dense stands of small diameter trees found in forests where naturally occurring forests have been suppressed.
  • Disturbance
    A discrete event, either natural or human induced, that causes change in the existing condition of an ecosystem.
  • Deciduous
    Plants that shed their leaves seasonally.
  • DBH
    Diameter at Breast Height, the standard measurement of tree diameter as measured 4 ½ feet above the ground.
  • Cultural control
    The establishment of competing vegetation to suppress the incidence of undesirable plants. 
  • Coniferous
    Cone bearing.
  • Community
    An assembly of organisms that tend to occur together under similar environmental conditions; usually considered to be on a smaller spatial scale than an ecosystem.
  • Climax species
    The final species to dominate a site by replacing early succession species through the mechanism of competition.
  • Chemical control
    The use of herbicides to reduce the incidence of undesirable plants. 
  • Channel
    A noticeable or artificial waterway featuring periodic or continuous running water. 
  • Catastrophic wildfire
    A wildland fire outside of the historical range of variability both in terms of size and intensity.
  • Canopy cover
    The percent foliar cover in a forest stand (may consist of one or several layers).
  • Broadcast burn
    The implementation of prescribed fire to meet fuels reduction, or resource management goals.
  • Board foot
    The amount of wood contained in a board 1 inch thick, 12 inches wide and 12 inches thick.
  • Biological control
    The use of plant’s natural enemies in order to control the distribution of that plant.
  • Biodiversity
    The number of species, the amount of genetic variation or the number of community types present in a area.
  • Biennial
    A plant that lives for two years.
  • Best management practice
    Resource management practices that are designed to prevent or reduce undesirable side effects to implementation of management actions.
  • Basal area
    The cross-sectional area of a tree stem measured at 4 ½ feet above the ground, expressed in square feet per acre.
  • Basal leaves
    Produced at the ground level.
  • Aspect
    The compass direction of slope of the land.
  • Annual
    Living through only one growing season.
  • Advanced ecological status
    A biotic community with a high coefficient of similarity to a defined or perceived potential natural community from an ecological site, usually late seral or potential natural community ecological status.
  • Adaptive management
    A process for implementing management decisions that requires monitoring of actions and adjustment of decisions based on results. Adaptive management applies scientific principles and methods to improve management decisions incrementally as experience is gained and in response to new scientific findings and societal changes.