Wildland fires are both natural and inevitable and play an important ecological role on the nation’s landscapes. These fires have long shaped the composition of forests and grasslands, periodically reduced vegetation densities, and stimulated seedling regeneration and growth in some species. Wildland fires can be ignited by lightning or by humans either accidentally or intentionally. As we have described in previous reports, however, various land use and management practices over the past century—including fire suppression, grazing, and timber harvesting—have reduced the normal frequency of fires in many forest and rangeland ecosystems. These practices contributed to abnormally dense, continuous accumulations of vegetation, which in turn can fuel uncharacteristically severe wildland fires in certain ecosystems. According to scientific reports, several other factors have contributed to overall changes to ecosystems and the landscapes on which they depend, altering natural fire regimes and contributing to an increased frequency or intensity of wildland fire in some areas. For example, the introduction and spread of highly flammable invasive nonnative grasses, such as cheatgrass, along with the expanded range of certain flammable native species, such as western juniper, in the Great Basin region of the western United States—including portions of California, Idaho, Nevada, Oregon, and Utah— have increased the frequency and intensity of fire in the sagebrush steppe ecosystem. Changing climate conditions, including drier conditions in certain parts of the country, have increased the length and severity of wildfire seasons, according to many scientists and researchers. For example, in the western United States, the average number of days in the fire season has increased from approximately 200 in 1980 to approximately 300 in 2013, according to the 2014 Quadrennial Fire Review. In Texas and Oklahoma this increase was even greater, with the average fire season increasing from fewer than 100 days to more than 300 during this time. According to the U.S. Global Change Research Program’s 2014 National Climate Assessment, projected climate changes suggest that western forests in the United States will be increasingly affected by large and intense fires that occur more frequently. Figure 1 shows the wildfire hazard potential across the country as of 2014. In addition, development in the wildland-urban interface (WUI) has continued to increase over the last several decades, increasing wildland fire’s risk to life and property. According to the 2014 Quadrennial Fire Review, 60 percent of new homes built in the United States since 1990 were built in the WUI, and the WUI includes 46 million single-family homes and an estimated population of more than 120 million. In addition to increased residential development, other types of infrastructure are located in the WUI, including power lines, campgrounds and other recreational facilities, communication towers, oil and gas wells, and roads. Some states, such as New Mexico and Wyoming, have experienced significant increases in oil and gas development over the past decade, adding to the infrastructure agencies may need to protect. Under the National Forest Management Act and the Federal Land Policy and Management Act of 1976, respectively, the Forest Service and BLM manage their lands for multiple uses such as protection of fish and wildlife habitat, forage for livestock, recreation, timber harvesting, and energy production. FWS and NPS manage federal lands under legislation that primarily calls for conservation; management for activities such as harvesting timber for commercial use is generally precluded. BIA is responsible for the administration and management of lands held in trust by the United States for Indian tribes, individuals, and Alaska Natives. These five agencies manage about 700 million surface acres of land in the United States, including national forests and grasslands, national wildlife refuges, national parks, and Indian reservations. The Forest Service and BLM manage the majority of these lands. The Forest Service manages about 190 million acres; BLM manages about 250 million acres; and BIA, FWS, and NPS manage 55, 89, and 80 million acres, respectively. Figure 2 shows the lands managed by each of these five agencies. Severe wildland fires and the vegetation that fuels them may cross the administrative boundaries of the individual federal land management agencies or the boundaries between federal and nonfederal lands. State forestry agencies and other entities—including tribal, county, city, and rural fire departments—share responsibility for protecting homes and other private structures and have primary responsibility for managing wildland fires on nonfederal lands. Most of the increased development in the WUI occurs on nonfederal lands, and approximately 70,000 communities nationwide are considered to be at high risk from wildland fire. Some of these communities have attempted to reduce risk of wildland fire through programs aimed at improving fire risk awareness and promoting steps to reduce their risk, such as the Firewise Communities program. Wildland fire management consists of three primary components: preparedness, suppression, and fuel reduction. Preparedness. To prepare for a wildland fire season, the five land management agencies acquire firefighting assets—including firefighters, fire engines, aircraft, and other equipment—and station them either at individual federal land management units or at centralized dispatch locations in advance of expected wildland fire activity. The primary purpose of acquiring these assets is to respond to fires before they become large—a response referred to as initial attack. The agencies fund the assets used for initial attack primarily from their wildland fire preparedness accounts. Suppression. When a fire starts, interagency policy calls for the agencies to consider land management objectives—identified in land and fire management plans developed by each land management unit—and the structures and resources at risk when determining whether or how to suppress the fire. A wide spectrum of strategies is available to choose from, and the land manager at the affected local unit is responsible for determining which strategy to use—from conducting all-out suppression efforts to monitoring fires within predetermined areas in order to provide natural resource benefits. When a fire is reported, the agencies are to follow a principle of closest available resource, meaning that, regardless of jurisdiction, the closest available firefighting equipment and personnel respond. In instances when fires escape initial attack and grow large, the agencies respond using an interagency system that mobilizes additional firefighting assets from federal, state, and local agencies, as well as private contractors, regardless of which agency or agencies have jurisdiction over the burning lands. The agencies use an incident management system under which specialized teams are mobilized to respond to wildland fires, with the size and composition of the team determined by the complexity of the fire. Federal agencies typically fund the costs of these activities from their wildland fire suppression accounts. Fuel reduction. Fuel reduction refers to agencies’ efforts to reduce potentially hazardous vegetation that can fuel fires, such as brush and “ladder fuels” (i.e., small trees and other vegetation that can carry fire vertically to taller vegetation such as large trees), in an effort to reduce the potential for severe wildland fires, lessen the damage caused by fires, limit the spread of flammable invasive species, and restore and maintain healthy ecosystems. The agencies use multiple approaches for reducing this vegetation, including setting fires under controlled conditions (prescribed burns), mechanical thinning, herbicides, certain grazing methods, or combinations of these and other approaches. The agencies typically fund these activities from their fuel reduction accounts. Risk is an inherent element of wildland fire management. Federal agencies acknowledge this risk, and agency policies emphasize the importance of managing their programs accordingly. For example, Forest Service guidance states that “the wildland fire management environment is complex and possesses inherent hazards that can—even with reasonable mitigation—result in harm.” According to a 2013 Forest Service report on decision making for wildfires, risk management is to be applied at all levels of wildfire decision making, from the individual firefighter on the ground facing changing environmental conditions to national leaders of the fire management agencies weighing limited budgets against increasingly active fire seasons. For example, the report explains that, during individual wildland fires, risk can be defined as “a function of values, hazards, and probability.” Congress, the Office of Management and Budget, federal agency officials, and others have raised questions about the growing cost of federal wildland fire management. According to a 2015 report by Forest Service researchers, for example, the amount the Forest Service spends on wildland fire management has increased from 17 percent of the agency’s total funds in 1995 to 51 percent of funds in 2014. The report noted that this has come at the cost of other land management programs within the agency, such as vegetation and watershed management, some of which support activities intended to reduce future wildfire damage. From fiscal years 2004 through 2014, the Forest Service and Interior agencies obligated $14.9 billion for suppression, $13.4 billion for preparedness, and $5.7 billion for fuel reduction. Figure 3 shows the agencies’ total obligations for these three components of wildland fire management for fiscal years 2004 through 2014. After receiving its annual appropriation, the Forest Service allocates preparedness and fuel reduction funds to its nine regional offices, and those offices in turn allocate funds to individual field units (national forests and grasslands). Interior’s Office of Wildland Fire, upon receiving its annual appropriation, allocates preparedness and fuel reduction funds to BIA, BLM, FWS, and NPS. These agencies then allocate funds to their regional or state offices, which in turn allocate funds to individual field units (e.g. national parks or national wildlife refuges). The Forest Service and Interior agencies do not allocate suppression funding to their regions. These funds are managed at the national level. Federal wildland fire management policy has evolved over the past century in response to changing landscape conditions and greater recognition of fire’s role in maintaining resilient and healthy ecosystems. According to wildland fire historians, in the late 1800s and early 1900s, the nation experienced a series of large and devastating fires that burned millions of acres, including highly valued timber stands. In May 1908, federal legislation authorized the Forest Service to use any of its appropriations to fight fires.