Glossary for wildfire research

The definitions provided here are designed to assist with searching the Annotated Bibliography of Wildfire Research database and may not capture the full meaning of the term in a broader context. For more definitions from other agencies see the links below.

Search tips

  • Try searching for any term that seems relevant to your interests. For example, studies that cover multiple counties do not have each county available in the drop down, but the individual counties covered may be searchable via the search box. This is also the case for studies that cover multiple plant species or vegetation types. If you leave the Plant Community/Association drop down empty, typing “forest” into the search box will bring up studies from all forest types, as well as studies that cover multiple vegetation types that include some information on forests.
  • Please note that there are many additional searchable terms that are not included in this glossary, so even if you do not see a term in the glossary, it may still yield results if you search for it.
  • Searching for partial terms will also return results for many of these terms. For example, searching for “masticat” will yield results that include the terms “mastication”, “masticate”, and “masticator”.
  • If you are having trouble finding resources for the term you are searching, please refer to the list of search terms below to verify spelling conventions.  For example, the bibliography uses “fuel break” as opposed to “fuelbreak” or “fuel-break,” and “non native” as opposed to “nonnative” or “non-native.” The list of search terms will clarify which terms to use for the best results.

Search Terms

Active Management – Using herding, fencing, or a supplemental water or food source to manage where livestock are grazing.

AET – Actual Evapotranspiration, the amount of water that is transpired by an ecosystem or community.

Age Class – Describes the age of a plant community, typically in relation to time since last fire or age at the time of a fire event.

Air Tanker – Large aircraft used to deliver fire retardant.

AWC – Soil available water capacity, a measure of the amount of accessible water held in the soil.

Biodiversity – Describes the variety of species found in an ecosystem or community.

Biological Soil Crusts – These are conglomerations of bacteria and/or algae that live on the soil surface that play a large role in nutrient cycling in nutrient poor environments.

BLM – Bureau of Land Management

Cal Fire – California Department of Forestry and Fire Protection

Cattle – Cattle grazing tends to be more focused on cattle production than fuels management or restoration.

Channel Incision – When water forms channels instead of evenly percolating into a landscape, increasing runoff and reducing soil moisture.

Climate Change – Increasing global average temperatures and changes in weather patterns due to fossil fuels use and livestock production.

Climate-driven Fire – Fire that is driven by weather despite low fuel availability.

Defensible Space – A fuel break around a human development or home.

Diversity – The variety of species, or habitats in an ecosystem.

Dozer Line – A fuel break created by a bulldozer.

Drought – A period of abnormally dry weather sufficiently prolonged for the lack of water to cause serious hydrologic imbalance in the affected area.

Ecological Fire Management – Managing fire fighting operations to allow fire to perform beneficial ecological services.

Ecological Restoration – Actively assisting in the recovery of a degraded, damaged, or destroyed ecosystem.

Erosion – A process which moves soil through the movement of wind or water.

Facultative Seeding – A species that has seed that is triggered to germinate by fire, and is also able to resprout from its root system post fire.

Fire Driven Type Conversion – Type conversion that is driven by a severe fire event or series of short interval fires.

Fire Exclusion – The practice of fighting all fires regardless of threat that has led to a buildup of fuels in many ecosystems.

Fire Intensity – Fire intensity is the amount of energy (heat) released in a wildfire.

Fire Line – A fuel break that is installed while actively fighting fire.

Fire Regime – The pattern of fire frequency and intensity in a landscape over time.

Fire Return Interval – The pattern of fire frequency in a landscape over time.

Fire Severity – Fire severity measures the effects of fire intensity on plant communities, typically measured as the post fire percentage of live plant cover.

Fire Spread – The rate at which fire spreads across a landscape.

Fire Suppression – The act of fighting fires to stop their spread.

Firefighting Trap – The idea that years of heavy handed fire suppression has created conditions that cause severe fires that require further heavy handed suppression.

Fuel Break – Any modification in fuels or vegetation with a goal of reducing the intensity or slowing the spread of a fire.

Fuel Break Effectiveness – Studies with this term will discuss the factors that influence the ability of a fuel break to slow the spread of fire or reduce its intensity.

Fuel Break Maintenance – Studies with this term will discuss the required maintenance to keep a fuel break in functional condition or management techniques to achieve this.

Fuel Break Placement – Studies with this term will discuss where fuel breaks should be placed to have the largest benefit to firefighting efforts.

Fuel Management – Managing fuels and vegetation to reduce the severity or spread of fire.

Fuel Reduction – Any treatment aimed at reducing the amount of fuel and vegetation to reduce the severity or spread of fire.

Fuel-driven Fire – A fire that has sufficient fuels to burn despite unfavorable weather conditions (i.e. low winds, low temperatures, or high humidity).

Functional Type Conversion – The loss of a species that causes a change in ecosystem services (i.e. the loss of a nitrogen fixing species).

Goat – Goat grazing tends to focus on fuel reduction or the restoration of an ecosystem.

Grazing – The use of livestock for fuel reduction, restoration, or food production.

Hand Crew – A crew using hand tools to create a fire line, fuel break, or to reduce fuel loads.

Hand Thinning – Using hand tools to reduce fuel loads.

Heterogeneity – Variation in vegetation across a landscape.

Home Hardening – Using materials that are more resistant to ignition to reduce the chance of a home burning during a fire.

Hydrology – The movement and retention of water across a landscape.

Industrially Managed Forest – A forest that is managed for producing timber.

Invasive Species – A non-native plant species that is well adapted to outcompeting native plant species.

Ladder Fuels – Vegetation that can carry fire from the surface into the canopy of trees.

Leading Edge  – The lower elevation or southern edge of a plant community that is the most vulnerable to drought and increased temperatures.

Logging – Harvesting trees for timber production.

Mastication – The use of heavy machinery to chop, grid, or chip vegetation.

Mechanical Fuel Treatment – The use of machinery to reduce the amount of vegetation or fuels.

Mediterranean-type Climate – A Mediterranean climate is defined as having hot dry summers and cool wet winters.

Mixed Severity Fire – A fire with a mosaic of low, moderate, and high severity burn patches.

Monitoring – Studies with this term discuss monitoring grazing projects to avoid damage to the ecosystem and to more effectively achieve the goals of grazing.

Non-native – A plant species that has been introduced from another bioregion.

Obligate Resprouting – Species that are able to resprout after a fire event, they recruit seedlings sporadically in between fire events.

Obligate Seeding – Species that are killed by fire and rely on recruitment of seedling to repopulate.

Piosphere – The zone of ecological impact around a livestock watering point.

PSM – Plant secondary metabolites are substances manufactured by plants that make them competitive in their own environment, often making them unpalatable or toxic to herbivores.

Plantation – A densely planted stand of often single aged trees for timber production.

Planting – Planting container stock for restoration purposes.

Ponies – Effects of grazing by wild ponies.

Post-fire Endemic – An annual, biennial or short lived perennial species that only germinates from a dormant seed bank after a fire event.

Prescribed Burning – The controlled intentional burning of a landscape to reduce fuel loads.

Rare Species – Plant species that are uncommon or have a restricted range.

Recovery – The natural recovery of a landscape after fire or disturbance.

Remote Fuel Break – A fuel break that has been constructed outside of the WUI.

Restoration – Actively assisting in the recovery of a degraded, damaged, or destroyed landscape.

Retardant – A chemical treatment used to slow or stop the spread of fire.

Richness – A measure of the number of different species in an ecosystem.

Santa Ana – Strong hot and dry downslope winds that blow offshore in southern California typically from October through January.

Seeding – Applying seed in restoration projects.

SOD – Sudden Oak Death is a disease caused by the fungus-like plant pathogen Phytophthora ramorum.

Stand Age – Describes the age of a stand of vegetation, typically in relation to time since last fire or age at the time of a fire event.

Stand Replacing Fire – A high severity patch of fire that causes the complete loss of live vegetation.

Sundowner – These downslope winds blow offshore from late afternoon to early morning in the Santa Ynez Mountains.

Surface Fuels – Vegetation and litter that is growing or has collected on the soil surface.

Targeted Grazing – Grazing with a specific goal to reduce fuels, reduce or enhance a particular species, restore ecological function, or increase the heterogeneity of a landscape.

Time Since Last Fire – The amount of time since a landscape previously burned.

Type Conversion – The loss of a species or suite of species that are replaced by a different functional species or vegetation type.

USFS – United States Forest Service

Vegetation Type Conversion – The loss of a species or suite of species that are replaced by a different vegetation type.

Water Deficit – When evaporative demand exceeds available soil moisture.

Wilderness – Natural environments that have not been significantly modified by human activity, designated wilderness areas receive the government’s highest level of land protection.

WUI – Wildland Urban Interface, where unoccupied wildlands meet human developments.