The workshop’s two keynote speakers reviewed what fire science in the United States has accomplished in the last 100 years and what the results of that research reveal for the next 100 years. Dr. Stephen Pyne, a historian at Arizona State University, presented on the U.S. history of fire science research. He was followed by Dr. Jennifer Balch, director of Earth Lab at the University of Colorado, Boulder. Each answered questions from the audience following the presentation.
Stephen J. Pyne, Arizona State University
Pyne began by saying he appreciated the fact that the Forest Service considers history as part of its mission. Many fire problems are, in some ways, historically constructed, so understanding how that evolution has occurred is crucial to understanding how to respond to fire today. The history of wildland fire research is the story of ideas (many of them very old) and of institutions (most of them quite young) and how the two have come together.
Pyne gave a brief prologue about the turning point in the history of fire science before examining that history with specific regard to the United States. He said that turning point was when the earth’s keystone species for fire—humans—shifted its combustion habits from burning living biomass and surface fuels to burning fossil biomass. He labeled this shift a “pyric transition,” a move from open fire in landscapes and domiciles to one of fire in combustion chambers. The shift to industrial burning also had an intellectual component because fire ceased to have autonomy as a field of science. Unlike the other elements—air, water, and earth—fire would henceforth be studied as a subset of other forms of learning. Fire as a science in its own right would be suppressed just as open flames were suppressed following the shift to industrial burning.
The United States’ fire-science story began in earnest in the late 1800s, coincident with the Industrial Revolution. Up to that point in time, fire was a common occurrence on the
land. It was used by Native Americans and later by settlers for many purposes, including clearing land and preparing fields. Indeed, slashing and burning on an industrial scale was common in other colonized places, such as Australia, Canada, and Russia (Pyne, 2010). The United States, like its colonizing peers with large tracts of forested land, responded to rampant slashing and burning with state-sponsored conservation, which set aside and put under national control large tracts of land that had once been inhabited by indigenous peoples (Pyne, 2010). These tracts then needed to be surveyed. A survey of western lands conducted by John Wesley Powell in the 1870s, resulted in, among other things, the first map of fires (Figure 3-1). Powell’s map was included with other material gathered by Charles Sargent for the 1880 U.S. Census report on forests (Sargent, 1884) to create a map of forest fires in the United States (Figure 3-2). Sargent, who was the director of the Arnold Arboretum at Harvard University, went on to be instrumental in rallying the National Academy of Sciences to sponsor the National Forest Commission (Box 3-1), which investigated how to manage the new forest reserves preserved by the federal government.
The linkage between forestry and fire management made in the National Forest Commission’s statement of task persisted in the commission’s recommendations; the connection between the two was then translated from those recommendations into federal legislation and into the mission of the newly formed Forest Service in 1905. Forestry as a discipline in the United States thus inherited the task of managing fire in the forest reserves, which of course required information on which to base that management. However, forestry was a young discipline in the United States, and it had no academic heritage of fire or fire management. Early U.S. foresters such as Pinchot were trained in Europe, where fire was seen as preeminently a social problem and was stigmatized as primitive (Pyne, 2010). A person’s or a society’s use of fire signaled whether the person or society was rational or primitive, and this point of view was exacerbated by the politics of the time, which were preoccupied with expansion and imperialism. Bernard Fernow, the first U.S. professional forester (originally from Prussia), equated the use of fire by Native Americans and settlers with bad habits and loose morals. He declared, as did others, that fire protection was not properly a part of forestry; rather, fire protection needed to be in place before forestry could be conducted.
The result was that the Americans who inherited the task of understanding landscape fire dismissed fire as a legitimate part of an ecosystem and wanted to remove it from the landscape. Like Fernow, Gifford Pinchot saw the removal of fire from forests as a necessary precondition to managing the forest reserves. This view became embedded in the Forest Service and was solidified by the Big Burn of 1910 (see Box 2-1), which challenged the ability of the agency to fight fires. The light-burning controversy, which also flared up in August 1910, challenged the Forest Service’s authority to make policy, while the Weeks Act, passed by Congress in 1911, created the circumstances for the formation of a truly national forest system (Box 3-2). Thus, for Henry Graves—who succeeded Pinchot as Forest Service Chief in 1910—protecting forests from fire was, as he said, 90 percent of American forestry. William Greeley, who would succeed Graves as chief in 1920, said in 1911 that firefighting was a matter of scientific management, in principle no different than silviculture or other techniques. Two decades later, Earle Clapp, associate chief and acting chief in the late 1930s, agreed, arguing that forest fire research was the United States’ responsibility because there was no precedent in Europe. In part to address this need for forest fire research, a branch of research was established within the Forest Service in 1915. Experimental forests, including those for fire, were in place by 1916.
However, the real motivator for fire science in the Forest Service was Coert DuBois, a forester in California. In 1914, he published the results of his study, Systematic Fire Protection in the California Forests (Dubois, 1914). He used operations engineering of his day,
Taylorism, in which the operation is broken down into its component parts and numerical values are assigned to each part. The research agenda attached to that operational breakdown sought to identify better numerical values for the component parts and smooth out some of the transitions between parts. The end goal was to prevent fires by finding them early, suppressing them quickly, and controlling the cost. His approach would soon become a national model.
A problem that confronted this approach was light burning, that is, the use of fire as a management tool for ecosystem or livelihood objectives. It was still a common practice of new settlers and farmers in the early 20th century. In the western states, the Forest Service tried to deter the persistence of light burning by systematically protecting demonstration forests and areas from fire to serve as an alternative (and presumed better) approach to forest management. In the South, woodsburning (the regular burning of forests) was viewed as a chronic, endemic problem. Demonstration forests were created to show the benefits of excluding fire from forests. However, the demonstrations showed exactly the opposite; fire exclusion was the wrong approach. The proponents of protecting forests from fire continued experimenting to prove the worth of fire exclusion. In the end, they failed and instead suppressed evidence that supported the value of woodsburning. The American Forestry Association went so far as to create the Dixie Crusaders, modeled on Billy Sunday evangelism, to roll into southern towns, set up big tents, and get people to take the pledge to swear off woodsburning. In the 1930s and 1940s, the Forest Service hired John Shea, a professional psychologist, because woodsburning seemed so illogical and resistant to the science of the day (that is, fire exclusion) that the only possible explanation for a propensity for woodsburning had to be psychological. In fact, the woodsburners in the southern towns had the right approach for managing fire in the forests in a way that preserved the function of the forest ecosystem and sustained their livelihoods.
Throughout the 1920s, the Forest Service consolidated its political position and its grasp over research. In 1921, Chief Greeley organized the Mather Field Conference, the first national conference held by the Forest Service. The topic was fire. In 1922, Harry Gisborne became the Forest Service’s first dedicated fire researcher. The Clarke-McNary Act, passed by Congress in 1924, strengthened the ability of the Forest Service to work with state officials to protect forests, particularly from fire. The Forest Protection Board, established in 1928, made the Forest Service the lead federal agency for any public lands that had forests, and in the same year, the McSweeney-McNary Act established a comprehensive program of forest research in the agency, effectively making it the sole entity conducting fire research.
A large amount of resources became available under the New Deal programs of the 1930s—in particular through the Civilian Conservation Corps—to mobilize men to fight
fires. It was thought that the goal of systematically controlling fire across the country could be achieved with this mobilization of labor, and science was rallied to support that objective. At that time, a great deal of research was put into fire-danger rating systems because it provided an administrative index for measuring the performance of controlling and excluding fire against field conditions.
Critics of the mission to rid forests of fire began to surface in the mid-1930s, especially among people interested in wildlife and people who wanted to reinstate traditional burning of various kinds. Nevertheless, the big western fires of 1934 inspired the Forest Service to announce an all-out policy of fire suppression, an experiment that was carried out across the country. In 1935, Chief Ferdinand Silcox put in place the “10:00 a.m. policy,” which instructed foresters that every fire should be suppressed by 10 a.m. the day following its initial report. To help promote that policy, the first fire publication, Fire Control Notes (USFS, 1936), was produced the following year. In 1937, Alfred Folweiler published what would be considered the first textbook on fire, Forest Fire Prevention and Control in the United States (Folweiler, 1937).1
Prior to the New Deal, the Forest Service relied on fire reports. The money accompanying the New Deal provided support for fire research, including laboratories and instruments that could be hauled out to the field to measure conditions as they were. By early 1940s, wind tunnels had been developed and crib fires were being used.2 Mechanical engineering, closely associated with Forest Service fire research pioneer Wallace Fons, was beginning to encroach on the field. World War II was a fire war, as is evident from the fires following the Hiroshima atomic strike. Pyne said that this event and the strategic bombing survey after World War II convinced many authorities that the next war would also be a fire war. Therefore, they saw a need to find ways to further weaponize fire as well as ways to be protected from it. At the time, the only people who knew anything about large-scale fire were foresters.
Immediately following World War II, Arthur Brown—who was the fire control chief for the Forest Service’s Denver regional office and would become the agency’s fire control chief in 1947 and fire research chief in 1950—rewrote Folweiler’s text (Brown and Folweiler, 1946), in which he reemphasized that the forest fire problem of the United States was unique and that European forestry had nothing to offer in terms of solutions. American foresters had to grapple with fire, but because their training followed a European tradition, they had no serious academic basis for the challenge. That same year, S. B. Show and B. Clarke wrote Forest Fire Control (1953) for the Food and Agriculture Organization of the United Nations, thus exporting around the world the American experience and model of fighting forest fires.
During the Cold War years, surplus war equipment was quickly converted for use in fire protection, which facilitated the mechanization of the war against fire. In 1954, Operation FireStop was launched. Its goal was to find out if the mobilization of science that had been so powerfully demonstrated in World War II could be applied to fire.3 Federal and state agencies, universities, and aircraft and chemical companies began to study, among other things, techniques for attacking fire from the air. Several equipment development centers were created at this time.
1 In his presentation, Pyne made note of several prominent textbooks in fire science published between the 1930s and the present day. The textbooks can be found in his presentation, available at http://dels.nas.edu/UpcomingWorkshop/Century-Wildland-Fire-Research/AUTO-5-97-34-D?bname=besr. Accessed July 2, 2017.
2 Crib fires are used to study the burning rate of fuel structures. Cribs are three-dimensional grids of sticks (the fuel); they are built with different stick thickness and density to learn about the burning rate of the fuel material given the spacing of that material.
The Forest Service also became involved in other types of fire and related engineering such as the atomic bomb testing program to better understand the fires that would result. Foresters were excited about this opportunity because it gave them some credibility and newfound standing in the scientific field. The rise in standing helped launch a National Research Council committee on fire research to provide “advisory and consulting services to the Government in the establishment and conducting of a research program on the spread and control of large fires” (NRC, 1962:1). There was also investment in several mass fire projects.4 The National Fire Coordination Study, which was the National Cohesive Strategy for Wildland Fire Management of its day, was initiated to determine what could be done to confine damage from nuclear fire. Therefore, the 1950s saw the undertaking of a number of large-scale field experiments and new disciplines involved in the study of fire—such as aeronautical engineering, mechanical engineering, and meteorology—which had not previously been a part of the fire-science scene.
More investment was put into the National Fire Danger Rating System because the system was a mechanism for bringing together this new research. The rating system was also a way of establishing national standards and performance guidelines to measure success and costs. Other scientific investments were more questionable. For example, fire scientists pursued the idea that they might end fires by suppressing lightning or modifying the weather. Notably, other countries prone to wildland fire, like Canada and Australia, did not pursue such strategies. However, this approach was effective for increasing federal investment and interest in fire science research, which helped the Forest Service establish three national laboratories in Macon, Georgia; Missoula, Montana; and Riverside, California.
One of the most outstanding fire scientists of this period did not begin his career as such. George Byram was a physicist among foresters. He worked at the Appalachian Forest Experiment Station in Asheville, North Carolina, which was not a center of fire activity when he was hired in 1936. However, his work from the 1930s through the 1960s applying physical science to fire phenomenology contributed greatly to the understanding of fire behavior.
In 1960, the Forest Service was identified in a famous study as a paragon of public administration (Kaufman, 1960). By the early 1960s, the Forest Service was a hegemon: The agency controlled directly or indirectly virtually all research on fire. “Practically every institution and exercise that involved free-burning fire had it as a member, if not a master” (Pyne, 2010:45).
Fires in the 1960s supported a Cold War mentality of civil defense. One of the first fires of this era was the Bel Air–Brentwood fire in southern California in 1961. Two images are telling about this era (Figure 3-3). The first is an image of Richard Nixon on a rooftop with a water hose (Figure 3-3A), which Pyne displayed to demonstrate that fire has always been a political project. The second is of Willard Libby, a Nobel laureate in chemistry, who had a house in Bel Air. The image shows him in a fallout shelter, which was built for $30 using sandbags and railroad ties (Figure 3-3B). However, his fallout shelter, along with his house, was incinerated in the fire. Thus, even if fire was used as a weapon, it could not necessarily be controlled.
Against the backdrop of the war in Vietnam, the campaign against fire continued. Just as war surplus equipment had been substituted for the workforce of the Civilian Conservation Corps, so information produced by the new Forest Service laboratories was substituted for the mechanical muscle of the equipment. The National Fire Danger Rating System became
a sophisticated project and now included fire behavior models. The Rothermel model in particular was a remarkable achievement; however, unwavering commitment to it may have affected the direction and outcomes of more recent modeling work. Operations research also developed during this time: the Incident Command System5 grew out of the 1970 and 1977 fires in southern California.
However, in the 1960s and 1970s, a fire revolution was also developing. There was a large-scale protest against both the philosophy of excluding fires from forests and the institutions responsible for enforcing that exclusion. In the 1960s, federal agencies were given new charters, and some were given new categories of land, such as “wilderness” following passage of the Wilderness Act in 1964. Wilderness was defined in the law as a place “untrammeled by man” and “where man himself is a visitor who does not remain” (P.L. 88–577); over 3.6 million hectares (9 million acres) of national forest land became part of the National Wilderness Preservation System. Other federal agencies, such as the National Park Service, wanted to break the hegemon the Forest Service held over fire science so they could implement their own policies, control their own programs, and have their own branches of research. What followed these changes in management philosophy and land definitions was a fragmentation of the Forest Service’s control of fire research. The Forest Service reoriented from fire control to fire management, and funding for fire research from the U.S. Department of Defense and from civil defense that had followed World War II and continued through the Cold War began to recede.
The emergence of a civil society—that is, nongovernmental entities interested in fire and forest management—accompanied this fire revolution. The Tall Timbers Research Station was an independent, privately run preserve established in Florida in 1958 to study fire on the landscape. In 1962, it held its first fire ecology conference. The conference was remarkably successful and played a key role in the insurgent movement against the Forest Service’s monopoly on fire science research. In the same year, the Nature Conservancy, a nonprofit conservation organization founded in 1951, conducted its first prescribed fire. Today the Nature Conservancy manages prescribed burns on as much land each year as the National Park Service. The Forest Service pursued the traditional sense of fire as an integrated subject while the civil society researchers turned toward fire ecology.
The revolution pushed the idea that fire needed to be restored to the landscape. This central tenet led to many questions about smoke management. Thought was also given to adapting fire behavior modeling for prescribed fires and for lightning-ignited fires that could be managed in ways similar to prescribed fires.
In 1978, a big change at the Forest Service followed this revolution in thought, including in the area of research. Interagency cooperation in the federal government became vogue, though not yet in research. However, there were many new funders of fire science, including the National Park Service, other agencies in the U.S. Department of the Interior (DOI), and (to some extent) the National Science Foundation. Long-term ecological research sites
5 The Incident Command System (ICS) is “a management system designed to enable effective and efficient domestic incident management by integrating a combination of facilities, equipment, personnel, procedures, and communications operating within a common organizational structure, designed to enable effective and efficient domestic incident management. A basic premise of ICS is that it is widely applicable. It is used to organize both near-term and long-term field-level operations for a broad spectrum of emergencies, from small to complex incidents, both natural and manmade. ICS is used by all levels of government—Federal, State, local, and tribal—as well as by many private-sector and nongovernmental organizations. ICS is also applicable across disciplines. It is normally structured to facilitate activities in five major functional areas: command, operations, planning, logistics, and finance and administration.” See https://training.fema.gov/emiweb/is/icsresource/assets/reviewmaterials.pdf, accessed August 14, 2017.
were established in 1980; they were a very different kind of demonstration forest in which fire was a part of the ecosystem. Fire ecology at this point was seen as a means of making prescribed burning and restoration possible.
The fire revolution stalled in the 1980s. Between 1978 and 1990, Forest Service research funding collapsed, in particular forest fire and atmospheric science research. Over this period, that area of research experienced a 46-percent drop in funding. However, the concept of the wildland–urban interface was developed successfully in the mid-1980s. The Forest Service led the work in this area, in part because there were no serious alternatives.
The fire revolution started up again in the 1990s. The first journal dedicated to wildland fire science, the International Journal of Wildland Fire, began publication in 1991. The National Biological Survey was formed within DOI in 1993 as that department’s consolidated arm of biological research. A traumatic fire season in 1994 led to the Federal Wildland Fire Policy in 1995. In 1996, the National Biological Survey was subsumed by the U.S. Geological Survey in DOI, back where it began. The National Interagency Prescribed Fire Training Center was established in 1998. Statistics were collected for the first time on different categories of fire. Also in 1998, Congress appropriated funding for the Joint Fire Science Program (JFSP) to support the use of fire and fuels treatment with the goals of reducing severe wildland fires and improving ecosystem health.6 The JFSP operates through an interagency partnership between DOI and the U.S. Department of Agriculture for research, development, and applications related to fire science, and Pyne opined that it is one of the real success stories of the last few decades. The fire revolution was pursued outside the United States as well, in nations such as Portugal, Russia, Canada, South Africa, and Brazil.
In 2000, the National Fire Plan was implemented. It allocated a good deal of funding for fire science and gave the field political attention, but it also made the treatment of fuels (for example, through thinning or prescribed burning) the only measure of action. Measurement based on fuels treatment appeals to forestry because it keeps the focus of fire science on trees rather than on fire itself. Administratively, the amount of area thinned or prescribed burned and the effects of those treatments are easier to quantitatively account for than other effective but less measurable wildland fire management approaches.
In the early 21st century, fires are bigger, more communities have burned, and firefighters have continued to die. This situation was and is truly a crisis for the Forest Service. It has led to the coinage of the term megafire. The wildland–urban interface has received increased attention during this period. Changes in funding or the absence of funding have created almost an existential crisis for the agency. However, at the same time, there has been an enormous expansion of disciplines within and related to fire research and an explosion of relevant publications. Therefore, while today may be the time of megafire, it may also be the meta-fire era because of the volume of research and analysis.
Nevertheless, Pyne observed that the additional research does not seem to be abating the challenges presented by fire. Where it had once been a model agency, the Forest Service has more recently been identified by people such as the political scientist Francis Fukuyama as the epitome of dysfunctional democracy (Fukuyama, 2014). Pyne said this characterization is unfair, but it nonetheless has serious effects on the national forest system because of the Forest Service’s lynchpin place in that system.
In an effort to put the pieces together, the Forest Service, in cooperation with agencies from DOI, rolled out the National Cohesive Wildland Fire Management Strategy in 2014. Pyne found the strategy particularly interesting because the subtext that accompanies the
document is the recognition that the problem of managing wildland fire is political, not just policy-oriented. The strategy is a kind of fire constitution, needed to make sure all the players understand the parts they play.
Pyne displayed two graphs, one that showed the increase in the costs of fighting fires in recent years and the other showing fire publications based on the E. V. Komarek bibliography at the Tall Timbers Research Station7 and on Web of Science (Figure 3-4). The curves of the two graphs are the same. If the money being spent on fighting fire is not changing the occurrence of megafires, Pyne noted that the same could be said about the return on investment for all the research going into fire science. Therefore, the increase in publications indicates that there is more fire science as it has been traditionally carried out, but it also indicates that more fields of science are identifying with fire. For example, the fields of remote sensing, geographic information systems, emissions studies, atmospheric chemistry, and modeling are all more involved in fire science today.
Pyne returned to where he opened, with a discussion of human civilization. Today’s civilization is one based on fossil fuels. That determines where people live, the direction of climate change, and the cause of many ecological pathologies. Therefore, Pyne suggested that perhaps the Anthropocene epoch should be renamed the Pyrocene epoch. To demonstrate this point, he showed a photograph of the Tallgrass Prairie Preserve in the Flint Hills of Oklahoma. Bison freely range and there are free-burning fires, but the landscape is also filled with pump jacks and pipelines carrying oil. Even areas like the preserve are framed by a fire-driven civilization.
Traditionally fire history has been thought of as a subset of natural history, particularly climate history. Pyne suggested that in the future there may have to be a pyric inversion—an acceptance that natural history and climate history are subsets of fire history because fire is what is enabling humans to affect the planet as they are. Making this mental shift would create the possibility of a new narrative framework for fire, to give fire some autonomy as a scientific discipline.
Pyne concluded that today is an era of new ideas in fire science from many different fields. Even traditional ecological knowledge is being promoted. Fire is seen as an informing presence, if not an informing principle, although it still has no intellectual tradition of its own. Instead, fire science is funded because of the problems that fire seems to cause. The Forest Service is no longer a hegemon of fire research and fire control, and new institutions now contribute to what is known. They also have funding and agendas of their own. Fire as a topic of research and related research programs has been globalized.
Pyne predicted an opportunity for big science projects going forward, akin in scale to those undertaken in Operation FireStop in the 1950s. He suggested a FireStop II to mobilize research into how new digital technologies can be of use to fire science; an accompanying National Cohesive Strategy for Research could integrate that research with all that is known from other disciplines involved in fire science. He also suggested that, in terms of science and management, fire culture matters more than fire science. A fire culture can work with fire, with or without science. Great science is not useful if it cannot be translated into institutional cultures. Pyne proposed that it was no longer possible for science to provide information about the conditions of the past and about what future conditions will be. An inflection point has been passed and science will instead provide metrics about the changes that humans are causing and elucidate what those changes mean for the future. Fire history may also be at a major inflection point, and managed wildfire serves as a symbol. It
is a hybrid fire, half suppression, half prescribed burn. Pyne asked how managed wildfire should be thought of, that is, how it fits into an understanding of the relationship of science in management.
Chief Forester Dale Bosworth noted several times during his 2001–2007 tenure that fire would shape the future of the Forest Service in the 21st century, and that seems to be the case. Although the Forest Service is no longer an indispensable agency, a national system of fire management and fire research will not function without it. The agency is still a major player, catalyst, and supplier for achieving critical mass, and it is still a place where ideas will be tested in the field.
Questions. Dar Roberts began the brief question and answer session by asking Pyne about climate change. He wanted to hear Pyne’s thoughts about what is to be done when climate change affects the ecological rules of the way fire operates, so that what has been learned in the past cannot necessarily be applied to manage fire in the future. Pyne said he would return to one of his opening observations, that the issues seen now are historically constructed. We cannot return to a path we left, he said, but the past tells us why our conditions today look the way they do. Observations of the past do not reveal what should be done. There was hope that fire science could guide a return to the original path. If the right science was invested in, the missing parts could be identified and the dots could be connected. However, Pyne was doubtful fire science could guide any return to an earlier path. Instead, what he sees from people in the field is that they are pursuing managed wildfire or other kinds of operations as the best options of many bad alternatives.
A participant asked Pyne whether it is good or bad that fire is not necessarily an academic discipline and is instead a problem-oriented, applied science. Pyne replied that the place of fire in academic study is a reality. Fire had a heritage in the ancient world. For Aristotle, it was a model system. The other ancient elements all have academic disciplines and whole university departments. However, this is not the case for fire. The only interest in fire as an integrated subject or as an autonomous subject will be because of problems related to it. Pyne said the absence of an academic discipline has to be accepted, and approaches are needed to bring together the varied fire interests to help understand the problem in its totality.
Another participant asked Pyne to elaborate on his vision for a National Cohesive Strategy for Fire Science Research. Pyne said that, given the variety of people and disciplines involved in fire, to avoid a continuation of the rising publication curve that does not translate into effects on the ground, a way needs to be found to bring the strengths of these various components together. He reiterated that a FireStop II model could be an effort to beta test some of these ideas. Traditionally, the Forest Service provided that kind of integration, but that has not been the case for some time.
Jennifer K. Balch, University of Colorado, Boulder
With an opening caveat that she did not possess a crystal ball, Balch laid out her presentation’s goal to provide information and perspectives from science about fire in the United States over the last few decades. Those perspectives and information are an important starting point for projecting and thinking about what future fire regimes will look like. Specifically, Balch’s talk concentrated on the role of people in current and future fire in the United States. As a physical geographer and a fire ecologist, Balch has spent a great deal of time thinking about how fire works in systems, and throughout her career she has continued to come back to the important role that people play in changing fire.
The question that percolates in scientific communities these days is: When and where are hotter and drier conditions creating an opportunity for human ignitions to spread? To answer that question, Balch started by looking at what science knows now: fires are increasing in number and size. Figure 3-5 shows an imprint of fire across the western United States using a U.S. government mapping project called Monitoring Trends and Burn Severity (MTBS), which is administered by the U.S. Geological Survey National Center for Earth Resources Observation and Science and the U.S. Forest Service Remote Sensing Applications Center. Each of the colored bars represents a different ecoregion, and in all ecoregions
but one the number of fires has increased since the start of the data set in 1984. Evidence from a slightly different record shows that, starting in the 1970s and going to the present, the number of fires over 400 hectares (1,000 acres) has been on the rise (Westerling, 2016). This trend is linked to two important phenomena. One is temperature anomalies. The other is earlier onset of spring.
Fire scientists think about the triangle of fire, which consists of three ingredients: climate, fuels, and ignitions. While the recipe appears to be simple, variations of those ingredients and the effects of people’s action on them create endless complexity. With regard to climate, recent work by Abatzoglou and Williams (2016) shows that anthropogenic climate change has resulted in more dried fuels and has doubled the amount of western forests that have burned since 1984. Abatzoglou and Williams looked at eight different metrics of fuel aridity, ranging from the Palmer drought severity index to vapor pressure deficit, which is a combination of temperature and relative humidity. In each of these eight metrics, they found that anthropogenic climate warming accounted for over 50 percent of the increase in fuel aridity from 1979 to 2015. They then linked the changes in fuel aridity to the amount of forest fire area that has burned, starting in 1984 and going through 2015. The data in Figure 3-6 show that there is a stark increase in burned areas related to specifically anthropogenic climate change and drying of fuels. Therefore, the effect humans are having on climate is changing how fire is expressed on the landscape.
The second ingredient is fuels. People have radically changed fuel structures through actions like thinning, logging, agriculture, road networks, fragmentation, and introducing invasive species. Balch focused on an example of how people are changing fuels through the introduction of the invasive species cheatgrass. In the Great Basin, it covers an area of about 40,000 km2 and is most prominent in northern Nevada. In her work, Balch matched
that ground cover with the burned area measured from space by the Moderate Resolution Imaging Spectroradiometer (MODIS) to look at the relationship between cheatgrass and burning. Her work found that cheatgrass burned an area twice as large as any of the native vegetation species over a period of a decade; it accounted for about 12 percent of the total land area burned (Figure 3-7). Another example is the Hot Pot fire in northern Nevada in 2016. This lightning-ignited fire burned approximately 48,500 hectares (120,000 acres) in 30 hours; the flames spread quickly over a large area because of the carpet of cheatgrass that covered the terrain and filled in the space between native vegetation.
The third ingredient is ignitions. In the last few decades in the United States, humans have started over 84 percent of wildfires. Balch and her colleagues recently looked at the human role of fire in the conterminous United States by using the U.S. Forest Service-sponsored Fire Program Analysis fire-occurrence database (FPA-FOD), compiled by Forest Service ecologist Karen Short (Balch et al., 2017). They found that people are expanding fire’s natural niche across the conterminous United States. Humans start the majority of fires and, more importantly, humans are tripling the length of the fire season by providing ignitions when lightning does not. The length of the human-ignited wildfire season in the United States is about 150 days a year, whereas the length of the lightning-ignited fire season is only about 50 days a year. Because of that influence, the wildfires that people start dominate an area seven times greater than the area affected by lightning fires, and people are responsible for 44 percent of all the area burned in the conterminous United States.
Balch and her colleagues based their analysis on the more than 1.5 million records in FPA-FOD of wildfires that were suppressed in the conterminous United States over a
2-decade period (Figure 3-8). That database also contains information about the cause of wildfires. Of the 1.5 million records of wildfires in the database, 1.3 million of those fires were started by people, and 260,000 were started by lightning.
Balch further stated that the spatial distribution of the wildfires recorded in FPA-FOD shows the strong dominance by people as igniters of fires in both the eastern United States and in Mediterranean California whereas lightning dominates the cause of fires in the inner mountain region (Figure 3-9). The distribution displays the spatial patterning of where lightning occurs and starts fires, but it also reflects where people live, how they live, and how they are using those landscapes.
In looking at the potential for people to change and shift fire regimes, it is necessary to understand the natural sources of ignitions. Balch and her colleagues looked at the density of dry lightning strikes (occurring with less than 2.5 mm of precipitation) and the percentage
of total lightning strikes that were dry lightning in the western United States between 1992 and 2013. Figure 3-10 shows a high concentration of lightning strikes in the southwestern states, many of which occurred with dry conditions, while lightning strikes were relatively absent from Mediterranean California. They found 97 percent of all fires in Mediterranean California were caused by people. This percentage is drastically different from that of the Sierra Nevadas, where dry lightning was much more common and people accounted for only 34 percent of fire ignitions.
Balch has also looked at the seasonal and temporal distributions of human-ignited fires and of lightning-ignited fires. Plotted temporally over the calendar year, human-ignited and lightning-ignited fires display noticeable patterns (Figure 3-11). The data show that human-ignited fires are prevalent in the spring in the eastern United States and common in the summer and the fall in the western United States. In Texas and Louisiana, burning occurs in all seasons. By comparison, most lightning-ignited fires occur in summer months, regardless of location. The number of human-ignited fires is high in the spring because of early spring burning in the eastern United States. After a decline that begins in mid- to late April, the number of human-ignited fires spikes on July 4; this is the day of the year with the most human-ignited fires. Balch said this phenomenon—the most fire ignitions on a single day occurring on a holiday that involves fireworks—speaks to Pyne’s point about the importance of the cultural mark on fire. It is evident from the temporal distribution of fire across the year that human-caused ignitions play a large part with regard to fire, in addition to climate and fuels. Figure 3-11 shows that people are adding 850,000 fires during the times of year (spring and fall) when lightning strikes are rare. The summer distribution of lightning-ignited fires follows what is known from lightning climatology about when lightning strikes happen.
Balch pointed out that the distribution data were not exclusive to large fires. The data included any fire over 0.4 hectacre (1 acre) in size. Large fires are not the only kind of fire of concern. As an example, she mentioned the Sunshine Canyon fire, which occurred near
her home in Boulder in March 2017, a few days before the workshop. That fire was only 30 hectares (74 acres) in size, but it threatened over 1,000 homes. As a fire ignited by people, it also serves as an example of why it is important to think about how people are vulnerable to but also contributing to fire seasons.
When the temporal distribution of fire is looked at by ecoregion, Balch noted that there is variety depending on location (Figure 3-12). People play a bigger role or a lesser role in starting fire depending on the ecoregion. For example, as she mentioned before, 97 percent of the fires that start in Mediterranean California were ignited by people, as compared to the temperate Sierras, where only 34 percent of wildfires were started by people. However, Balch observed that 34 percent is still a lot of fire ignitions by people in a region that is less populated.
Looking deeper into the data set reveals that many human-ignited fires are connected to infrastructure and practices. Road networks and human-ignited fires coincide. Human-ignited fires also overlap with where people live. However, ignition patterns differ by ecore-
gion; for example, the density of human-ignited fires is much higher in Appalachia than in the West because debris burning is more common in Appalachia.
In her 2017 paper, Balch and her colleagues conceptualized fire as a species akin to an animal species or plant species that has criteria and environmental conditions under which it will exist. They separated the lightning-ignited fires from the human-ignited fires and plotted two of the most important criteria or conditions: ignition strikes from lightning and fuel moisture. After plotting all of the conditions in which fires happen, not surprisingly they found that the greater the number of lightning strikes in a region and the drier conditions, the more likely a fire would be ignited by lightning. The data show that people ignited fire during moister conditions and during times when lightning strikes do not occur. When the number of fires is plotted against fuel moisture for human-ignited fires and for lightning-ignited fires, the data reveal a pulse of human-ignited fires when fuel moisture is between 14 percent and 22 percent while few lightning-ignited fires occur at this range of moisture level; this demonstrates that people are providing the ignition source in moister conditions (Figure 3-13).
When they looked at large fires—those that are over 400 hectares (1,000 acres)—Balch and her colleagues found results similar to those of other fire-science efforts that have been focused on a record of large fires provided by the MTBS project. Large fires increased between the early 1990s and the early 2010s whether they were caused by humans or by lightning (Figure 3-14). Questions that are important for the fire science community to answer are: Why are human-ignited fires increasing? Are they increasing because the climate is warming and humans are providing the ignitions that a warmer climate then translates into larger fires? Are they increasing because more people are living in landscapes that can carry fires?
Examined by season, the data show that large fires are increasing to different degrees, depending on the season and the source of ignition. The increase in large lightning-ignited fires occurs mostly during the summer season, while the increase in human-ignited fires occurs in both the spring and the summer. Balch said that was important to know because, if there is an early spring onset of large fires, is it lightning that is providing those ignition sources, or is it people that are providing those ignition sources for fires to start?
Balch then posed the questions: What do these data and trends mean for the future of fire in the United States? Will the fire season contain more large and destructive fires going into the future? Before exploring those questions, Balch stressed that not all fire is bad. Fire benefits ecosystems. The message from all the recent work that she presented is not that more fires need to be put out; instead, more of the right kinds of fires need to burn. The re-
search shows that people are providing the ignition source for 84 percent of wildfires, so the next step is to think about how humans can influence the ignition of the right kinds of fires.
A key question that will need to be answered to understand what the future of fire will look like is how climate change will interact with people. Current research may be able to answer this question, and this area is also a research frontier. Balch and colleagues have matched human-ignited fires and lightning-ignited fires with the current scientific understanding of how short-term fire danger is changing because of climate change, so they can look at the intersection of people and climate with regard to fire. Work by Moritz and colleagues has projected future climate scenarios and how future fire activity will change given those scenarios, going from 2010 to 2039 to 2099 (Moritz et al., 2012; Figure 3-15). Those projections show that fire activity in the United States will likely increase relative to climate variables.
Another key piece of data needed to make predictions about the future of fire in the United States is information about where people live and where they are going to live in the future. About 10 percent of the conterminous United States’ current land area is wildland–urban interface (WUI), where houses are intermixed with wildlands (Figure 3-16). That percentage is projected to double by 2030. Furthermore, it is estimated that 80 percent of the land that could end up falling into the WUI is not yet developed. These projections need to be taken into account when thinking about where people are going to be the sources of ignition in the future and where they will be vulnerable to changing fire regimes. It is worth noting that, even with only 10 percent of the land in the WUI, thousands of structures were lost to wildfire between 1999 and 2011 (Figure 3-17). Many of these fires were started by people. Balch observed that humans create vulnerable structures and vulnerable infrastructure which are also vulnerable to human-ignited fires.
The projections of the future show that it will be important for humans to coexist and live more sustainably with fire. Because people in the United States live so close to flammable places and flammable landscapes, how people build and how people use fire will be important. Data aggregated by Headwater Economics identified over 4,000 U.S. communities that are located within 10 miles of where a fire of at least 40 hectares (100 acres) occurred between 2000 and 2014 (Headwater Economics, 2016). This proximity to fire justifies the need for communities to be “fire-wise” and for infrastructure to be better adapted to flammable places.
One idea for better adapted infrastructure is to borrow the concept of floodplains and create fire plains. Fire plain maps would provide data for incentives or disincentives connected to building. Such maps could be created for the entire country, much like the Federal Emergency Management Agency’s flood maps. California has been a leader in this work, putting together fire hazard severity zones to guide building in flammable landscapes. Information contained in Cohesive Wildland Fire Management reports about the frequency and severity of fire in different fire regime groups provides justification for fire plain maps.
In terms of how people use fire, Balch said fire science has enough data to support conducting more fires that have ecological benefits. The Coalition of Prescribed Fire Councils reported that over 47,000 km2 or roughly 12 million acres were treated with prescribed fire in 2014 (Melvin, 2016; Figure 3-18).
Some important lessons about adapting to living with fire come from communities around the world who are practicing patchwork mosaic burning and using it as a mechanism to reduce the risk of large climate-driven fires. For example, in Western Australia, the landscape around the Martu indigenous communities is a patchwork of lightning-ignited fires and smaller managed burn systems from aboriginal hunting fires (Bird et al., 2012). The community is effectively mitigating the risk of large climate-driven fires through their use of human-ignited fires. Such mitigation is justification for doing more of the right kinds of fire and using prescribed fire as a tool rather than treating fire as a threat. However, Balch acknowledged that it is difficult institutionally to incorporate that type of distributed network of prescribed burning back into the daily events of landscape management in the United States.
Balch also touched on the role of scientists and the power of big fire data. She conceptualized the metaphor of a modern day palimpsest. A palimpsest is a manuscript page from a scroll or book that the text has been scraped or washed off so that it can be used again. She likened the U.S. landscape to a living palimpsest that has imprints and memories from past uses of the landscape, from human use of fire, and from fire being part of that landscape. Today’s field of fire science is also a palimpsest because there is information and data from different sources that can help answer important questions about the future of fire. Scien-
tists have at their fingertips information spanning from the map of forest fires that Charles Sargent gathered in the 1880 census (Figure 3-2) to satellite imagery from multiple systems that, when combined, provide incredibly powerful visualization tools for looking at the fire landscape. There are also novel sources of information such as machine learning techniques and text analysis or natural language processing. These tools can be applied to incident reports from different agencies to mine the information in those reports for novel insights. Drones are another tool that will help scientists better understand ecosystem processes at a finer scale. Finally, social media data, such as searches for the term wildfire, help scientists understand social responses to wildfires.
Balch concluded with three major points to help reframe fire myths to realities. First, people play a fundamental role in changing fire, in concert with climate and fuels. Second, not all fire is bad; it can do good work in ecosystems. Third, people can and must live with fire and can do so by building better and making better use of fire.
Questions. Balch was asked whether fires started by human infrastructure were included in the number of human-ignited fires. The questioner pointed to the fires that burned in Gatlinburg and elsewhere in Sevier County, Tennessee, in the fall of 2016 as an example. While one fire was started by arson, many fires were caused by power lines. Balch responded that causes related to human infrastructure, like power lines and railroads, were included in the data set as categories and even subcategories. She said power lines are an important
ignition source, particularly during hot and dry conditions when people are running air conditioners. When the power lines become overloaded, they ignite new fires. Fires caused by such events are emblematic of some of the fire problems the United States is experiencing.
A participant asked if Balch had looked at the interior of Alaska and the change that is happening there. Balch replied that her 2017 study did not include Alaska because other good work that looks at the role of human- and lightning-ignited fires in Alaska has already been done. She also noted that there are many important cultural differences reflected in the data on Alaska.
Another participant wanted to know the source of the data in Balch’s 2017 paper. He also wondered if Balch had found a way to relate that data to satellite data. With regard to the satellite data, Balch said she is currently working on matching government records of wildfire with satellite data from MODIS, Landsat, and the Visible Infrared Imaging Radiometer Suite. She is finding that there is not complete congruence between the data sets. There are fires in the government record that are not seen in the satellite records and vice versa. She said this lack of congruence points to the need for an Uber-style data set on fire, in which all these different sources of information are combined to get a full picture of fire. The source of the data for her 2017 study was the Fire Program Analysis fire-occurrence database, which Karen Short compiled and integrated. Balch noted that Short works for the Forest Service and should be acknowledged for her work because it opened the door for the type of inquiry pursued in the 2017 study. Short deserves credit for putting
so much effort and dedication into compiling this information and reducing the number of redundant records.
Another participant noted that one of Balch’s figures (Figure 3-5) showed different ecoregions in North America, and fires were increasing in every ecoregion in the United States except Mediterranean California. He asked if anything from her analysis could explain why that was the case. Balch replied that she did not know why fires decreased in Mediterranean California, and she hoped that the audience at the workshop could help answer that question because important lessons are likely to be learned.