Although forest fires are a part of nature’s regrowth and regeneration process, the recent magnitude and intensity of wildfires are drawing greater awareness to the need for effective response and restoration activities.
When wildfires damage or destroy an area, they often introduce safety hazards and create a landscape that is more vulnerable to future damage. Wildfires affect the entire ecosystem, so it is important to approach wildfire response and restoration with a whole-system approach. A whole-system approach will consider a multitude of environmental factors, including air and water quality, soil chemistry, runoff control, land stabilization, and habitat restoration. Additional considerations may arise depending on where the wildfire occurred and whether it swept over existing infrastructure such as structures, utilities, water reservoirs, and mines.
STAYING GROUNDED: SOIL CHALLENGES
When a wildfire wipes out vegetation, the soil becomes more vulnerable to erosion and water becomes more likely to flow along different and new pathways. If the wildfire is severe enough, it can cause certain soil types to form a waxy ‘hydrophobic’ layer that prevents water from penetrating the soil, leading to increased water runoff issues. Wildfire season often coincides with dry conditions and storm events producing large runoff events. In addition, spring snowmelt and runoff can amplify erosion concerns the following year. A wildfire often causes flooding issues that allow sediment to move downstream, altering normal stream channels and impacting reservoirs and/or community water supplies. When wildfires occur near infrastructure and development, toxic substances can also be created (e.g. polyaromatic hydrocarbons or PAHs), and sediments in the water may transport contaminants downstream, presenting additional environmental challenges.
When a wildfire occurs, the United States Forest Service’s (USFS) Burned Area Emergency Response (BAER) program begins assessing the environment to protect life, property, water quality, important landmarks, and ecosystems from further damage. A major component of BAER’s work involves stabilizing hillsides and modifying drainage mechanisms to better control water during subsequent storm/flood events. However, the BAER program’s primary concerns are short-term and the emergency actions they need to take may not always be designed to create a sustainable environment. Further longer-term landscape design is often required to ensure the landscape can return to a productive state.
TROUBLED WATERS: WATER QUALITY CHALLENGES
Wildfires can impact multiple aspects of water supply and treatment, from source water in streams to the water that flows out of residential faucets. With approximately 80 percent of the U.S.'s freshwater originating on forested land, wildfires can have significant downstream impacts by damaging the watersheds communities rely on for irrigation and public drinking water systems. The downstream impacts from a wildfire can lead to additional costs for water treatment facilities due to increased sediment, debris, and contaminant removal requirements.
Runoff from burned areas contains ash, which can affect the water chemistry of lakes, wetlands, reservoirs, and rivers. These changes can create the need to alter drinking water treatment or habitat management practices. In addition to the chemical changes to water caused by the fire itself, the mechanisms used to combat the flames can present new challenges. Though typically considered harmless to humans and land animals, fire retardants may potentially demonstrate a level of toxicity to aquatic organisms.
If a fire burns in a watershed that has been mined and revegetated, runoff can transport metals from the burned area to streams. Additionally, increased groundwater flow through mine infrastructure can push more metals into the surrounding water bodies.
INVISIBLE IMPACTS: AIR QUALITY CHALLENGES
Wildfire smoke introduces a complex mixture of chemicals, gases, and fine particles. The biggest health threat from smoke comes from breathing fine particles. Particulate matter from smoke can be small enough to enter the lungs and may even travel to the bloodstream. Depending on the circumstance, an Air Resource Advisor (ARA) may be assigned to a wildfire response team. ARAs can then help with air quality monitoring, smoke dispersion modeling, predicting future air quality, and communicating information to the public.
LAYING DOWN ROOTS: VEGETATION/HABITAT RESTORATION CHALLENGES
Vegetation, in addition to offering short-term soil stabilization services, also defines what makes forest lands so valuable to the public and surrounding wildlife. Losing a forest to a severe fire eliminates the potential for timber production, which is often critical to forest managers. Loss of the forest canopy also reduces the habitat available to support the diverse wildlife that depends on the structural complexity of forests to survive. Thus, vegetation restoration activities after a fire prove critical in setting a forest on a successful path of return.
Once short-term mitigating measures as described above are implemented, a long-term commitment to habitat restoration is necessary to ensure forests continue down a successful restoration pathway. Left unmanaged, many once forested lands can turn into invaded landscapes with no potential to recruit trees. Trees are necessary to establish an adequate forest overstory, so weed/invasive plant and reseeding efforts can help move a forest toward a desirable state. Ultimately, vegetation management is a long-term commitment and cannot be resolved in a single management event.
BRINGING IT ALL TOGETHER: RESTORING THE ECOSYSTEM
Despite the significant challenge wildfires present, there are practical and proven restoration activities that can help a forest return from severe fire and prevent future damage. A whole-system approach will assess the land-water-air nexus as one. While wildfire response plans are routinely customized for a given scenario, restoration generally involves a combination of some common elements, including:
- Preliminary site assessment: For larger or more remote locations, unmanned aircraft systems (UAS) and remote sensing can be leveraged to perform preliminary site surveys.
- Waste management: For more urban-impacted locations, certified technicians can identify and remove household hazardous wastes including lead and asbestos containing materials.
- Sampling: Soil and groundwater may have been impacted by metals, perfluorinated (PFAS) compounds, pesticides, petroleum hydrocarbons, polychlorinated biphenyls (PCBs), and/or volatile organic compounds (VOCs). Collecting soil and water samples helps assess the extent of clean-up required to ensure complete site remediation.
- Water treatment: If local water sources become impacted, water treatment options should be evaluated and implemented.
- Stormwater protection: To reduce runoff pollution, stormwater management practices should be deployed and monitored.
- Revegetation activities: To balance the short-term needs of soil stabilization and invasion resistance while increasing the potential for long-term desirable plant community establishment, revegetation activities should be monitored on an ongoing basis. Even when best management practices are in place, plant invasions can still occur. Thus, an ongoing monitoring protocol to ensure Early Detection Rapid Response (EDRR) is recommended.
- Infrastructure rehabilitation: If infrastructure experienced damage, engineering support should be deployed to rehabilitate existing infrastructure or design new infrastructure to protect against future disasters.
Trihydro has ecological experts on staff with experience navigating post-wildfire response and restoration activities. Contact us today with your wildfire restoration questions.