Pacific Northwest Research Station

Understanding Fire Effects on the Environment

Wildfire is a part of nature. It plays a key role in shaping ecosystems by serving as an agent of renewal and change. But fire can be deadly, destroying homes, wildlife habitat and timber, and polluting the air with emissions harmful to human health. Fire also releases carbon dioxide—a key greenhouse gas—into the atmosphere. Fire effects are influenced by forest conditions before the fire and management action taken or not taken after the fire, and may be long-lasting.

Scientists with the Pacific Northwest Research Station are conducting a range of studies pertaining to fire effects on the environment in multiple fields of study, from meteorology to ecology. Learn more by clicking on a topic below to jump to that section.

Fire Behavior

Fire and Climate Change

Fire Ecology

Fire Preparedness

Fire and Smoke

Fuel Treatments

Fire and Weather

Fire in Western Oregon and Washington

Fire Behavior

Fire behavior broadly refers to a fire’s intensity and rate of spread. More specifically, it is the way fuel ignites and how flames develop. Scientists who study fire behavior are interested in factors that influence fire intensity and rate of spread, such as fuel types, weather, and topography. “Extreme” fire behavior indicates fire that does not respond to the usual methods of direct suppression, usually because of rapid spread, fire in the tree canopy (e.g., crowning), and formation of fire-related weather systems (e.g., pyrocumulus clouds). Station scientists have developed comprehensive syntheses of knowledge about extreme fire behavior for managers. Return to top.

• Air temperature, moisture content, and nighttime fire behavior explained (video)
• The Fire and Smoke Model Evaluation Experiment (FASMEE): improving fire and smoke forecasting to protect public health 
• Improved modeling of fire behavior and risk to structures in the wildland-urban interface
• Synthesis of knowledge of extreme fire behavior: volume 1 for fire managers
• Synthesis of knowledge of extreme fire behavior: volume 2 for fire behavior specialists, researchers, and meteorologists

Fire and Climate Change

Climate change is contributing to the increased risk and extent of wildfires in the Western United States. Wildfire risk depends on complex interactions between temperature, soil moisture, and the presence of trees, shrubs, and other potential fuels. All these factors have strong direct or indirect links with climate variability and climate change. Station scientists have found that climate change increases the potential for very large fires in the United States. Return to top.

• Climate change likely to alter postfire forest restoration patterns 
• Unprecedented fire provides opportunity to study what may be “new normal” 
• Fire severity, postfire treatments, and carbon storage 
• Climate change presents increased potential for very large fires in the contiguous United States
• Fire science experts achieve one-of-a-kind consensus
• Empirical estimates of future fire environments in the Pacific Northwest

Fire Ecology

Fire ecology explores the interactions between fire and the surrounding environment, including both living and nonliving things. Fire ecologists recognize that fire is a natural process that is often integral to the life history of plants and animals in the ecosystem. Station scientists study fire effects on ecosystems, fire history, how plants and animals depend on or adapt to fire, and fire regimes. A “fire regime” refers to the general pattern of wildfire’s natural occurrence in a particular ecosystem, including fire frequency, intensity, size, pattern, season, and severity. Return to top.

• Quantifying disturbance interactions among wildland fire, insects, and tree mortality  
• Using prescribed fire to enhance wildlife habitat 
• After long absence, fire-adapted knobcone pine can still respond positively to fire 
• California fires are influenced by topography
• Predicting survival of fire-injured trees in the Pacific Northwest 
• The effects of fall burning on cheatgrass cover 
• Effects of high-severity burning on soils 
• Fire as a tool: landscape-scale forest restoration that incorporated managed wildfire and prescribed fire led to more pronounced reductions in fire severity
• Legacies of past fires: in fire-prone ecosystems the legacies of past fires often dictate the characteristics of future fires
  
   

Fire Preparedness

Station scientists are studying factors that contribute to wildfire risk and community vulnerability across the region to help support fire-resilient forests and communities. Researchers are also characterizing risk to communities on the west side of the Cascade Range where fires are less frequent than on the east side, but potentially very destructive. Return to top.

• Evaluating rural Pacific Northwest towns for wildfire evacuation vulnerability 
• Hazards of risk: identifying plausible community wildfire disasters in low-frequency fire regimes
  
   

Fire and Smoke

Wildfire smoke is a public health concern in the Western United States. The Pacific Northwest Research Station is a nationally recognized leader in smoke science. The station’s BlueSky smoke modeling framework enabled the first comprehensive nationwide smoke forecasts and forms the basis for smoke prediction systems and tools used across the country and around the world. Scientists with the station’s AirFire research team developed the Fire and Smoke Map on the EPA’s AirNow website and mobile app that shares current air quality conditions and fire locations across the United States. Return to top.

• Research to help you breathe a little easier (parts one and two)
• Where there’s smoke, there’s ire
• Smoke in a new era of fire 
• The Fire and Smoke Model Evaluation Experiment (FASMEE): improving fire and smoke forecasting to protect public health 
• The U.S. Interagency Wildland Fire Air Quality Response Program 
• Comparing smoke and fire emission models 
• Station expertise used to help predict smoke from Southwest fires 
• Linking estimates of air quality and health impacts from smoke  
• Delivering smoke science to incident operations 
• Strategies to restore fire while protecting air quality 

Fuel Treatments

Fuel treatments are management actions that alter the amount or arrangement of forest vegetation to mitigate wildfire behavior and enhance fire resiliency. Fuel treatments can include mechanical thinning of dense stands of trees, piling brush, pruning lower branches of trees, or creating fuel breaks to encourage the right kind of fire. Prescribed fire is a form of fuel treatment. Return to top.

• Most mechanical fuel treatments immediately enhance resistance to crown fire 
• Strategically-placed fuel treatments, resilient landscapes 
• Enhancing wildlife habitat, reducing wildfire severity: stand treatments for multiple benefits   
• Fuel treatments: Are we doing enough? 
• Prescribed fire burn windows
• Evaluating effects of thinning and prescribed burns 20 years later 
• Fuel reduction in boreal forests affects fire behavior and fuel consumption 
  
   

Fire and Weather

Wind and weather have immediate effects on the ignition, behavior, and suppression of wildland fires. Station scientists study the complex meteorology—the climate and weather of a region—associated with wildland fires, including how weather conditions create severe wildfires. Return to top.

• Air temperature, moisture content, and nighttime fire behavior explained (video)
• The hot-dry-windy index improves fire weather forecasting
• Investigating smoke plume dynamics in Australia 
• Historical climate data and new maps aid prediction of large fires 
  
   

Fire and Western Oregon and Washington

The dense forests of the western Cascade Range in Oregon and Washington are known for their evergreen, wet conditions and infrequent wildfires. As the climate becomes warmer and drier, west-side forests are experiencing longer fire seasons, larger burns, and increased wildfire risk. Launched in 2019, the West-Side Fire Research Initiative aims to research and develop tools to support fire-related management on landscapes west of the Cascades. Through the initiative, scientists, fire managers, and stakeholders are working to coproduce the science needed to protect the health, safety, and economic well-being of communities in the region and support fire resilient forests. Return to top.

• A “new normal” for west-side fire in Oregon and Washington
• Fire and climate adaptation in Oregon and Washington west-side forests
• Pacific Northwest Research Station tackles the science behind 2020’s wild season of wildfire