The wildland fire environment around the world is undergoing profound ecological changes. These changes are triggering extensive shifts in the complexity, behavior, extent, and effects of wildfires that are not only placing ecological processes at risk but are increasing potential impacts to social, management, economic, and political values.
As society and management actions have gained emphasis to reduce the occurrence and extent of natural fire in grasslands, shrublands, and forests, fundamental shifts have occurred in the structure, composition, and volume of fuel and vegetation complexes. Diminished presence of natural fire accompanied by escalated presence of other land management activities resulted in increases in quantities of fine fuels, duff, large woody fuels, rotten material, shrubs, and other live surface fuels. Both vertical and horizontal fuel continuity, represented by shrubs, low vegetation, tree regeneration, and woody fuel layers has increased. Density and compactness of surface fuel components have increased. Wildfires occurring in these altered situations behave quite differently from historic fires, have markedly more severe impacts, and necessitate escalated needs for protection responses.
Prescribed Burning – A Flexible Management Tool
The application of fire for the treatment of natural fuels (live and dead vegetation; downed and dead materials; and duff, litter, and humus layers, etc.) has been conducted throughout much of the history of natural resource management, in varying implementation schedules and spatial scales.
This practice, prescribed burning, has emerged as a keystone land management process with multiple values. Fuels are the only element in the fire-vegetation-weather-topographic dynamic that managers are able to modify through management activities. It is now widely accepted that prescribed burning can mitigate the risk of severe wildland fire impacts to human communities, municipal watersheds, and valuable natural and cultural resources. It can reduce potential fire behavior, increase the potential success of suppression efforts, and maintain and improve the health and resiliency of ecosystems. Prescribed burning can be completed at scales ranging from site-specific to landscape orientations and range from single to combinations of treatments, and single to multiple applications over time.
Around the world, this practice has been characterized by numerous names such as prescribed burning, planned burning, controlled burning, and management-ignited prescribed fire. We should understand that different names have the same definition and are used interchangeably with prescribed burning. It can be defined as the pre-planned, controlled application of fire under specified environmental conditions to a predetermined area at the time, intensity, and rate of spread required to alter, maintain, or restore vegetative communities; achieve desired resource conditions; protect life, property, and values that would be degraded or destroyed by wildfire; and achieve other planned resource management objectives.
Regardless of exactly how prescribed burning may be known, it is an extremely versatile management tool that is increasing in importance and value. It can be used in any kind of vegetation and many different settings and situations. A variety of ignition techniques and firing patterns can be used that allow managers the ability to control intensity, flame lengths, spread rates, degree of consumption, daily and seasonal timing of burning, type and intensity of control tactics, and planned precision of objectives. Prescribed burning results can approximate other treatment methods in terms of the accuracy in accomplishing objectives and is certainly one of the most cost-effective treatment types. It can also have neutral or positive effects on ecosystems as opposed to large and active wildfires, which can have serious negative effects.
Prescribed burning can be conducted as pile burning or broadcast burning. Pile burning generally follows other treatments and is used to reduce woody debris remaining after those treatments. This type of treatment represents small scale, stand maintenance or hazard fuel reduction applications. It is not restricted to any particular season, although is not widely used during drier parts of growing seasons. Broadcast prescribed burning can be used singly or in combination with other treatments and removes natural and activity-generated fuels and modifies surface fuel complexes. This kind of burning has size limits only controlled by the situation and objectives. Consequently, it can be used in small-scale, large-scale, and landscape applications.
In some cases, multiple applications of prescribed burning may be needed to accomplish objectives. This is especially true for areas that have experienced continual fire suppression, have altered fuel complexes, or have substantial numbers of high values present, as is the case in the wildland-urban interface (WUI) area. The combination of mechanical non-fire and prescribed fire applications as a fuel treatment process in WUI areas has been widely and successfully used. This sequence allows the mechanical removal of ladder or vertical fuels followed by reductions in surface fuel amounts.
Prescribed Burning – Status
While prescribed burning has grown in use since the early to mid-twentieth century, it is still not used in all locations around the world. But many countries, such as the United States, Canada, Australia, Portugal, Spain, France, and South Africa, are implementing management plans that incorporate prescribed burning. Other countries have less mature programs and are in developmental stages regarding prescribed burning. In all places where prescribed burning is implemented, commonalities can be found that include references to its importance and value. Common references can be found stating that natural vegetation complexes are prone to wildfires; increased use of prescribed fire is necessary to treat fuels, restore fire-adapted landscapes, and to reduce the impact of wildfires on human communities, vegetation, soils, biodiversity, and ecosystem services; and clear needs exist to better understand how prescribed burning can be used to maximize benefits.
However, while the acceptance of its importance is increasing, prescribed burning is not necessarily widely accepted. It still has a certain amount of uncertainty, misunderstanding, social pressure to avoid even short-term negative impacts like smoke and burned vegetation, and fear of implementation breakdowns that cause reluctance to increase use.
Areas of Continued Focus
In those areas now moving into prescribed burning, a variety of basic needs exist. These include such things as developing planning procedures, standards, guidelines, qualification systems, training programs, implementation guidelines, evaluation processes, opportunities to gain experience, and learning feedback mechanisms.
In those areas where prescribed burning is an integral part of management activities, processes are better defined. Program areas of policy direction, objectives and framework for use, planning guidelines, risk frameworks, performance measures, training and qualification programs, science support, funding, and operational capability are well documented and practiced. Examples of overarching documentation describing the purpose and guidance for prescribed burning that has been developed includes:
- Guidance for Implementation of the Federal Wildland Fire Management Policy – addresses the use of fire to protect, maintain, and enhance resources (USA).
- National Cohesive Wildland Fire Management Strategy – the vision statement includes reference to use fire where allowable; and national goals are to restore and maintain landscapes, promote fire-adapted communities, and support wildfire responses; all of which are supported by prescribed burning activities (USA).
- National Position on Prescribed Burning – articulates nationally agreed upon principles for the development and implementation of prescribed burning policies and programs (Australia).
- Interagency Prescribed Fire Planning and Implementation Procedures Guide – defines purpose, scope, goals, authorities, required documents, implementation organization and qualifications, and responsibilities for the program (USA).
- National Burning Project – delivers a suite of products informing all levels of prescribed burning including objectives setting, planning guidelines, risk frameworks, performance measures, training manuals, support tools toolbox, and soon to be available synopses of best practices (Australia).
Regardless of the variation in the state of prescribed burning programs, there is room for refinement, improvement, and program advancement. Specific areas where additional practices and knowledge can be pursued include:
- Improving the ability to plan, implement, and evaluate ecological effects of prescribed fire treatments in achieving short- and long-term objectives at all spatial and temporal scales. Restoration and maintenance of ecological processes are primary goals of prescribed burning. However, prerequisite to the development of effective, ecologically sound guidelines for prescribed fire implementation is a need for improved understanding of ecological responses. Identification of areas most prone to significant fuel complex changes, assessment of anticipated spatial shifts in environmental suitability and vegetation related to future climate changes, evaluation of prescribed fire options for affecting spatial diversity in vegetation and fuel structure at meaningful scales, clarification of how to affect size and severity of large fires, and evaluation of opportunities for achieving resilience at landscape scales are all important areas of concern.
- Developing a better understanding of the relationship of prescribed fire to human values. There appears to be a disparate understanding of the role of prescribed fire, ecological benefits, economic trade-offs, and precise messages being delivered to the public. It is important that planning and implementation is based on a sound characterization of human values in terms of their impacts to, impacts from, and levels of tolerance of risk from the use of planned fire.
- Improving communication and collaboration activities among governmental units, the public, and partner organizations. Since collaborative prescribed fire management will ultimately involve trade-offs and decisions, the importance of understanding social perceptions about prescribed fire and the need to inform and engage with local and regional communities are essential requisites to program success.
- Developing and defining measures to evaluate prescribed fire program effectiveness. Evaluating the degree of success of prescribed fire program effectiveness and appropriate spatial and temporal scales in mitigating suppression costs, resource loss, risk, hazards, fire behavior, health impacts, and firefighter and public safety are important to continued program evolution and improvement. It is also important that better awareness and understanding of the longevity of effectiveness for fuel treatments is gained so that long-term maintenance needs can be defined.
- Establishing and maintaining a strong and efficient link between research and management. Prescribed fire research has a strong history and record of accomplishment in some parts of the world but is at a relatively early stage in many other parts of the world. A need for research and development to help address high priority knowledge and technology needs still exists.
The need for prescribed fire application in natural resource management is increasing. Changing fire environment conditions may be accelerating the rate of this increase. To keep pace with needs for reductions in potential fire behavior, support for success in suppression operations, and maintenance and improvement of the health and resiliency of ecosystems, we need to continue to develop and administer prescribed fire programs as part of land management plans.
To do this, we must continue to grow our capabilities. To learn more about ecological interrelationships, share information with developing programs, inform and educate the public, understand the trade-offs between prescribed burning and risk (both during the burn and in the postponed risk of unburnt fuel), and continue the essential investigations that improve or knowledge and best practices.
We must maximize all opportunities to expand every aspect of the prescribed fire program and must keep pace with ecological, social, and political needs and requirements of our fire-prone and fire-adapted landscapes.