Using fire to control fire

From Smokey Bear to today, federal agencies recognize use of controlled burns to prevent catastrophic wildfires

Prescribed burns are used to cost-effectively clear ranges of dense vegetation encroaching on open training areas. Public safety, asset protection, and natural resource stewardship can also be optimized from the well-managed use of fire. | U.S. Army photo

With the frightening images seen this year of human lives, homes, and huge forest areas being threatened by wildfires, it may be very difficult to recognize the counter-intuitive strategy of using controlled burns, to actually increase safety and the protection of natural resources.

According to the United States Department of Agriculture, Forest Service (USDA-FS), over 2 million acres of national forest and millions of state and privately-owned land were unintentionally burned in 2017.

Major fires treated to potentially exhaust agency fire resources. There were 550 crews committed nationally, and every capable federal agency was called upon to pitch in. In 2017 this included active duty military fire-fighting teams from the Army, Air Force, Marine Corps and Navy, along with other Federal, State and Local agencies and the National Guard in several states.

Ironically, some of the organizations literally on the front lines today of fighting those intense catastrophic fires are the most ardent proponents of the non-suppression of smaller naturally occurring wildfires and even the use of controlled burns, or “prescribed fires”, to reduce the risk of these large uncontrollable wildfires.

In fact, nationwide the Department of Defense (DoD) conducts over 600,000 acres per year of controlled fires in non-residential wild areas and ranges. The U.S. Forest service conducts even more. Human’s response and use of wildland fires has evolved over thousands of years, but intentionally starting fires to benefit man and wildlife is nothing new. It is believed that in the Yosemite Valley Native Americans used fire to manage game and the land at least 4,000 years ago. Nowadays, at APG and other military installations, controlled burns are not only recognized for their value to public safety and forest or grassland health, but also for the critical role they play in mission sustainment (see APG News cover story 30 November 2017). So how did we arrive here with this very serious and complex relationship with forest fires and what are the implications for safety, health, mission sustainment and natural resource management?

The new and evolving view on how to respond to, and prevent future catastrophic fires

Although Native Americans had been using intentional fires to enhance hunting, or for clearing horticultural areas, European colonists were concerned by the threat of wildfires to their built structures and permanent settlements. Perhaps the earliest documented legislation in that regard was a 1636 Massachusetts ban on smoking outdoors to prevent wildfires.

By 1872, it was believed that most fires in Yellowstone were started by campfires and for another century or more, policies and procedures were established to prevent or stop all fires in public forests. Those designated campfire areas in modern campgrounds are descendants of ones set up in public parks as early as 1889 to minimize wildfires caused by careless campers. The following year the military started assisting with fire-fighting and prevention in our National Parks.

It wasn’t until 1967 that the National Park Service revised their fire policy to allow “prescribed natural fires” with approved fire plans. They even changed the beloved Smokey Bear’s slogan in 2001 from “Only You Can Prevent Forest Fires” to “Only You Can Prevent Wildfires” to match the modern understanding that prescribed and controlled forest fires were beneficial and only uncontrolled “wildfires” were bad.

Today, the DoD, the U.S. Environmental Protection Agency (EPA), the U.S. National Park Service, the U.S. Forest Service all seem to be on the same page on this topic – small planned and controlled burns are a critical tool in effectively reducing the risks and impacts of large catastrophic wildfires that pose much greater risks to people, structures, natural resources, water and air quality.

The causes and prevention of wildfires

The “fire triangle” diagram is used by firefighters to illustrate the necessary components of a fire, namely: fuel, oxygen and a heat source. This knowledge helps in both preventing and extinguishing fires. Remove or reduce any one of the three: the fuel (remove excessive dead or dry vegetation), oxygen (smother flames or use chemicals that rapidly consume oxygen), or heat (apply water or foam, or benefit from more humid air or precipitation that may occur).

To prevent wildfires, an important priority is to reduce the potential fuel load available for the ignition and spread of fire. A long history of preventing and suppressing nearly all forest and grassland fires has led to a catch-22 situation in many locations. Large amounts of combustible shrubs, herbaceous vegetation, and/or dead wood (fuel) has accumulated in many areas, and fire may be the only practical way to remove it.

The longer neglected and more dense the combustible material is, the more likely small understory fires will grow into catastrophic crown fires, where the entire forest is engulfed from forest floor to tree canopy. Most large trees are adapted to survive periodic understory fires but not crown fires. Crown fires are also more difficult to control and pose a greater threat and risk of widespread unintentional damage.

Removing the initial heat source is another way to prevent wildfires. Lightning, intense sunlight (only in extremely dry situations), or lava flows are about the only way nature provides enough heat to start a fire. Most grassland and forest fires, perhaps 80-90% or more, are caused by humans. So another critical fire prevention technique has long been to educate humans to minimize their unintentional ignition of wildfires. According to the Maryland Department of Natural Resources, fire departments in Maryland respond to over 5,000 wildfire incidents per year and only 4% are thought to be caused by lightning. The other 96% are believed to be caused by humans: 28% by improper outdoor burning, 23% by arson, and the rest started by either vehicles or equipment (e.g., hot mufflers in tall dry grass), children playing with matches or lighters, smoking, railroads, downed power lines, discarded ashes or fireworks. Fortunately Maryland rarely has “crown fires” where the entire forest, from forest floor to canopy top, is engulfed producing catastrophic fires like the ones witnessed in California and other western states in 2017. Large catastrophic forest fires are more common in the western states.

The flames of a prescribed burn work their way through brush on an APG test range in January 2017. The road, seen in the foreground, serves as a firebreak helping to control and contain the fire to only the area deemed appropriate by the Aberdeen Test Center. As the fire runs out of fuel, it extinguishes itself. |U.S. Army photo by Amanda Rominiecki

Removing oxygen from the atmosphere isn’t really an option, leaving fuel and heat source as the two reasonable components to control to prevent wildfires.

Fire used as one tool to manage range vegetation at APG

Mechanical and herbicidal vegetation management is not efficient or even effective in all situations. Herbicides can kill vegetation but the decaying plants can create more potential fuel load for wildfires. The possible presence of unexploded ordnance (UXO) can be an issue on military ranges that makes mechanical vegetation removal by either vehicles, or individuals on foot, more dangerous and costly.

As the APG News has reported in the past, controlled burns can be a very effective alternative to remove unwanted vegetation encroaching on ranges that need to be kept open for the testing and training mission. The controlled burns at APG are not carried out to thin mature forests. Here they are used primarily to remove weedy grass and shrub or seedling size vegetation from open ranges.

Only trained and qualified professionals are permitted to submit plans, well in advance, for executing a controlled burn in a well-defined area surrounded by adequate fire breaks (roads, creeks, or pre-scorched areas used to prevent the spread of fire to protected areas). After the plans are reviewed and approved, burns may still not be executed unless weather and other conditions are optimal for a burn to be done safely and with minimal nuisance smoke or mission disruption.

Although the smoke can temporarily impair visibility and air quality during a controlled burn, it is nevertheless considered less impactful on air quality in the long term than the larger catastrophic wildfires that are being prevented, or from the motorized equipment that would have to be used multiple times during the growing season to remove vegetation mechanically to sustain open ranges.

Fire as a part of forest ecosystem cycles

Different species of vegetation and wildlife have different adaptations or responses to fire in nature. Large older growth and taller trees usually survive and can even benefit from periodic fires in the understory. Some tree species actually require periodic understory fires to sustain healthy populations and ecosystem balance.

According to a report on prescribed and wildland fires on military installations, prepared in 2014 for the DoD Legacy Resource Management Program, fires historically (especially before complete suppression policies were adopted) were more frequent but less severe in U.S. forests. Using analysis of soil layers, the ring patterns of long-lived trees, and other clues researchers concluded that compared to pre-industrial times in the U.S., after accounting for forests lost to development and agriculture, there is now a roughly 50% lower frequency of fires.

They suggest that our modern history of fire suppression nationwide has had negative impacts including loss of biodiversity in forests and a higher risk for more frequent and intense catastrophic crown fires. The conclusions of the report suggest that appropriate management practices on DoD installations should include wildland fire risk reductions in support of installation operations and that “…prescribed fire may be one of the tools used to meet resource management sustainability objectives.”

Effects of fire on humans and wildlife

There now seems to be widespread consensus in the scientific literature and among federal land management agencies that fire plays an integral role in many natural ecosystems. Fires can recycle organic matter by returning nutrients to the soil, disinfect plant diseases, kill harmful insects, remove dense invasive plants, and open the forest floor for new seedlings and germination of the seed bank present in the soil. Research has found benefits from fires to certain butterfly species and even whooping cranes in some habitats.

One ancillary benefit to humans of controlled burns at APG and elsewhere may be a reduction in ticks. The Army’s Public Health Center is studying this possible reduction in human encounters with the ticks that vector disease.

The visible flames and smoke seen during a grassland or forest fire are dramatic reminders of the major concerns associated with controlled burns. The safety of personnel, the protection of structures, and the protection of native flora and fauna are not only the top priorities of firefighters during a fire but also of those planning controlled burns. Planners must consider the proximity of humans and structures, the native flora and fauna present in and adjacent to the proposed burn area, and natural or man-made fire breaks that will allow for the confinement and control of a burn.

According to the Pennsylvania Game Commission controlled burn ignition patterns can be designed to slowly drive wildlife towards pre-planned escape routes or corridors for mobile wildlife. Large uncontrolled wildfires or “crown fires” in which the tree canopy is ignited travel as fast as 14-mph and can pose a far greater risk to humans and wildlife.

To protect the public, the National Cohesive Wildland Fire Management Strategy involves federal, state and local government agencies, tribes and NGO’s with “an all-lands, all-hands approach” to the challenge of wildfires across the nation. The strategy has three main components: 1. Resilient landscapes; 2. Fire adapted communities; 3. Safe and effective wildfire response.

The State of Maryland supports this strategy with the Maryland Firewise program. Public land managers and private land owners or communities can get assistance and guidance from this program to minimize the risk of wildfires and the damage they cause. The program encourages minimizing the fuel-load in forested or vegetated areas that might threaten people or structures. They recommend a “defensible space” of at least 30 feet around homes and other buildings where dead vegetation, leaves and other flammable materials are removed. Exit routes for people and clear access for emergency vehicles are also critical.

Obviously, but inconveniently for those with fireplaces and wood stoves, large stacks of firewood or stove pellets should not be stored close to the house. Controlled burns are not generally a practical tool in suburban or even many rural areas with extensive residential development so frequent mechanical removal by humans or machines is suggested.

All of these efforts can support the national strategy to develop more fire adapted communities and resilient landscapes that are managed to be less vulnerable to wildfires.

APG natural resources managers have a long history of continually coordinating the natural infrastructure stewardship that supports and sustains the Army’s testing and training mission every day. Working with partners from APG tenant organizations, the U.S. Fish and Wildlife Service and the Maryland Department of Natural Resources, APG DPW personnel developed and coordinated our Integrated Natural Resources Management Plan (INRMP) as a roadmap for a sustainable mission landscape that is created through proactive management of APG’s natural resources.


By John Leader, APG DPW, Natural Resources Team