[The following is reprinted from the University of Nevada’s Great Basin Wildfire publication edited by Dr. Elwood Miller, Dr. Rang Narayanan and Bob Conrad.]
The Great Basin is a high elevation, arid to semi-arid region with annual precipitation ranging from five inches in the most arid, lower-elevation locations to 30 inches in the upper elevations of mountain ranges.
This region extends eastward from the Sierra Nevada Range to the Wasatch Range in Utah and from Southeastern Oregon and Southern Idaho in the north to the Mojave Desert in the south. It includes most of Nevada and parts of Utah, Idaho, Oregon and California. Public land, managed by various state and federal agencies, comprises a substantial portion of the Great Basin.
A highly variable winter snow pack is the primary source of surface as well as subterranean water. Dry land and irrigated crop production, livestock grazing, mining and recreation are the primary economic activities tied to natural resources in the rural areas of the Great Basin. Substantial recent increases in population both within and outside the Basin have intensified the competition for land use and water resources of the Basin.
The distinctive ecosystem of the Great Basin is facing a serious crisis as a result of increased human activity and global climatic change. To a large extent, the spread of exotic invasive plants and noxious weeds, the expansion of the piñon-juniper woodland, the decline in the sagebrush/perennial grass and riparian ecosystems, accelerated soil erosion, changes in water supply and altered fire regimes are both symptoms and causes of this ecological system in peril. In the past decade, the Great Basin has experienced several fire seasons in which more than a million acres have burned. These events have evoked significant public concern and calls for renewed attention to our management of natural resources. However, fire has been a force in the Great Basin for many centuries.
Weather and evolved vegetation have combined to establish fire as a natural and consistent force across the landscape. Lifting of moisture-laden Pacific air masses by the Sierra Nevada and Carson mountain ranges results in west slope precipitation and drier air spilling eastward across the region. While devoid of moisture, these air masses contain the electrical charge necessary to generate high-intensity lightning storms. When this occurs during the hot, dry summer months, the result can be hundreds of fire starts across millions of acres of rangeland.
The frequent occurrence of fire played a significant role in shaping the distribution and species composition of the natural vegetation communities that occupied the Great Basin. Other contributing factors include soil type variations, elevation, erratic precipitation and daily and seasonal temperature fluctuations. The journals of early explorers document the commonplace occurrence of fire and also noted that not all fire ignitions had a natural origin. Fire was an important part of the Native American culture and was used as a tool to increase the availability of desirable plants, improve habitat for wildlife and to drive game species during hunting.
Also, because indigenous cultures are not known to have typically extinguished campfires, aboriginal accidental wildfire was probably common. Prehistorically, frequent recurrence of fire and other disturbances—including insects, drought and floods—produced a patchy mosaic of vegetation representing various stages of vegetation transition. In the broadest sense, three vegetation types dominated the landscape: 1) piñon-juniper woodland/mountain big sagebrush at mid-elevations; 2) Wyoming big sagebrush/perennial grass at lower elevations; and 3) salt desert shrub also at lower elevations. A minor plant community consisting of coniferous forest species existed at the highest elevations. The relatively frequent occurrence of fire played a major historic role in the distribution and composition of the first two major types but was a rare occurrence in the salt desert shrub type. However, with the invasion and aggressive establishment of red brome, fire has become more frequent and increasingly detrimental even in this type. Fire return intervals ranged from less than 20 years in the piñon-juniper woodland to more than 50 years in the Wyoming big sagebrush/perennial grass types. This natural rate of fire occurrence limited the expansion of the woodland by killing piñon and juniper seedlings established in the sagebrush / perennial grassland type and prevented sagebrush from becoming the dominant species to the detriment of the perennial grasses. All of this changed in the mid-1800s, coinciding with the end of the Little Ice Age and associated climate changes, and the westward population expansion that resulted in greatly increased permanent habitation dependent upon land use.
The history of early European man in the Great Basin is one of discovery and settlement. Discovery brought mining followed by ranching and occupation of remote locations throughout the West. The environment was altered by the various uses, resulting in changes to the landscape. The ecosystem of the Great Basin was altered by Native Americans for millennia prior to settlement by European immigrants. Change by European settlers, however, was accelerated by machinery and grazing animals.
Climate change and variable weather patterns also played a role in the dynamic nature of plant communities in the Great Basin. Periods of extended drought and/or infrequent above-average precipitation brought about corresponding changes in composition, density, distribution and productivity of the vegetation. During the last decades of the 1800s and the early decades of the 1900s, three important events occurred that set the stage for the vegetation complex that now spreads across the land and the degraded range conditions that raise concerns today.
First, the introduction of cattle, sheep and horses in the 1860s resulted in large scale ranching operations and severe overgrazing. The excessive grazing pressure removed the fine fuels that had carried the naturally occurring fire, which resulted in a substantial reduction in the number of fires and the acres burned. In the 32-year period—from 1880 to 1912—only 44 fires burning 11,000 acres were reported.
Second, as the end of the 19th century approached, undesirable exotic plant species were introduced into the Great Basin. The most prominent species is cheatgrass (Bromus tectorum), a native of Eurasia. The earliest herbarium collection of this invasive exotic annual grass in the Western U.S. dates to 1894. Not only does cheatgrass germinate in the later winter to early spring, but it sprouts above ground and begins root development before native species. As a result, it is highly competitive for both moisture and soil nutrients. Cheatgrass produces a fine-textured, highly flammable, early maturing fuel that increases the chance of ignition as well as increasing the rate at which wildfires spread. The result is greatly shortened fire recurrence intervals and larger fires. As native plant diversity has been replaced by large expanses of contiguous cheatgrass stands, the self-perpetuating fire cycle has opened the door to further site degradation and invasion by perennial noxious weed species. Every year cheatgrass is replacing sagebrush/perennial grass plant communities important to wildlife and agriculture and is fueling catastrophic wildfires that are devastating millions of acres of productive rangeland in the Great Basin.
Finally, the early decades of the 20th century ushered in a remarkable change in the way humans viewed wildfire. From a natural- or human-caused event that potentially created desirable outcomes, wildfire became viewed as the enemy—an enemy that had to be controlled and suppressed wherever it occurred. Total wildfire control became the widely enforced public policy, with large publicly funded fire fighting forces organized, trained and staged to extinguish any and all ignitions. The nearly century-long period of very successful fire control has greatly altered the frequency and character of fires that historically inhibited woodland expansion and restricted the presence of piñon and juniper to “fire-safe” sites. In addition, the total control of fire created large expanses of single-age sagebrush where the shrub cover is so dominant that herbaceous and perennial grass species are virtually absent.
As a result of these three events, the Great Basin landscape is now characterized by three major vegetation/wildfire fuel complexes: 1) large expanses of monotypic, highly flammable, annual grassland; 2) overly dense sagebrush stands with a meager understory of perennial grasses and forbs or annual exotics; and 3) greatly expanded piñon-juniper woodlands with a rapidly closing crown canopy and non-existent understory of perennial grasses and forbs. No longer is the natural force of fire characterized by frequent, low intensity burns that ensure the persistence of diverse, resilient, fire-adapted plant communities. Rather, the current fuel complexes are prone to large, catastrophic, high intensity burns that destroy the vegetation, degrade the soil and create conditions for the establishment of highly undesirable invasive weed species that defy efforts to rehabilitate the damaged sites.
Recognition of the role of wildfires in maintaining natural ecosystems was incorporated within the 1995 Federal Wildland Fire Management Policy and Program Review followed by a multi-agency effort, entitled “Review and Update of the 1995 Federal Wildland Fire Management Policy,” that was published in 2001. Agencies responsible for implementing an aggressive fire suppression policy expressed growing concern over the resultant accumulation of hazardous fuel and the impact on fire-adapted ecosystems. Following the fires of 2000 that burned 7.4 million acres and cost $1.36 billion to suppress, Congress adopted the National Fire Plan that requires a coordinated, multi-agency action plan to address the alarming increase in destruction to communities and natural ecosystems. In response to a presidential initiative following the destruction of 7.2 million acres and fire fighting costs that reached $1.66 billion caused by the fires of 2002, the Healthy Forest Restoration Act of 2003 was passed by Congress. The goal of this congressional action was to reduce large wildfires and restore range and forest lands.
The agency efforts and the subsequent legislation have led to increased appropriations to meet the escalating costs of fire suppression. The rising cost of fire suppression is due in part to a new wave of human settlement and development across the Great Basin. During the period from 1980 to 2000, 8.4 million homes were built in fire-dependent ecosystems across the West. The presence of this development has shifted the suppression resource deployment priorities from protection of natural resources to protection of lives and homes. Records maintained by the National Interagency Fire Center (NIFC) show that nationally, the wildland fire acreage has gone up from 8 million acres in 2004 to more than 10 million acres in 2007. The number of fires has increased from 65,000 in 2004 to more than 100,000 in 2007. The yearly number of fires in the two decades following 1960 typically ranged between 100,000 and 150,000. From 1983 through 2005, the average annual number of fires actually declined compared to the previous two decades and were mostly below 100,000. During the last four decades, the wildland fire acreage has also been smaller, typically ranging from 3 to 5 million acres. In recent years, nationally there has been less of an increase in the number of wildland fires, but the acreage burned has increased dramatically.
A somewhat similar pattern seems to emerge for the eastern and western Great Basin combined (as defined by the NIFC), which includes the states of Nevada, Utah, Idaho and parts of Wyoming. In the last three years, dramatic increases are reported in the acres burned by wildland fire. Burned acres increased from 128,978 acres in 2004 to about 3.3 million acres in 2007. Nationally, total annual fire suppression costs for all federal agencies between 1994 and 2005 ranged from $256 million to
$1.66 billion. The Bureau of Land Management estimates its total fire suppression cost for the western Great Basin alone to be $241 million from 1998 through 2007 to put out approximately 9,000 fires spanning about 7 million acres. Considering the fact that both fire suppression and damage costs are related directly to wildland fire acreage, it is reasonable to assume that total yearly suppression expenditures by agencies, as well as the lost value associated with destroyed natural resources and the ecosystem every year, warrant careful solutions to wildfire issues.
Present conditions are ripe for continued catastrophic wildfire events, the scale and frequency of which will continue to adversely impact the ecosystem and impose high economic costs on society. The prediction by rangeland scientists and fire ecologists is for more of the same unless a successful effort is undertaken to combat this dilemma. Dr. James A. Young, noted Great Basin range scientist, reported at a 2004 sagebrush ecosystem symposium that, “If we continue over the next 20 years as we have over the past 20 years, we will not recognize the Great Basin as we have known it.” The vast acreage burned by wildfires in Nevada alone since 2004 is evidence that Dr. Young’s prediction is rapidly coming true.
It is apparent that time is not on our side. The destructive force of wildfire is rapidly altering the unparalleled beauty and biodiversity of the Great Basin at an alarming rate. Startling losses of the sagebrush steppe due to wildfire has reduced critical habitat and raised the specter that sage grouse and other species may be listed as threatened or endangered. Further losses of the sagebrush ecosystem will threaten many other land uses including ranching, mining, hunting, fishing, recreation and the economic viability of rural communities.
Scientific discoveries and analyses lead to policy prescriptions and better management practices. Understanding the evolution of the natural ecosystem, the role of fire in that process, the impacts of humans on the landscape and, more recently, the effects of climatic changes, will provide the key to solving the ecological problems that we face today in the Great Basin. Science-based vegetation and wildlife habitat management, appropriate livestock grazing strategies, objective-based monitoring and an improved soil and vegetation database will provide the foundation for successful rangeland management. Reducing the damage caused by wildfire will require increased attention to pre-fire readiness and successful post-fire rehabilitation. Long term success in addressing the wildfire crisis will come from increased investment in rangeland education, research and management.
To gain a better perspective about the problems and possible solutions, recognized scientists were invited to participate in a Great Basin wildfire forum. The careers of these individuals represent decades of experience and research in the rangelands of the Great Basin. The knowledge, ingenuity and ability to provide critical analyses of both natural and administrative processes that have occurred over time resides with these scientists who have worked and lived in this environment for many years. What follows in this publication are the contributions of these scientists to the forum discussion and their recommendations.