Influences on Prescribed Burning Activity
in the United States National Forest System
(IFFN No. 19 - September 1998,p. 43-46)
Recent analyses of fire policy have called for increased prescribed burning to prevent future wildfire damage and enhance fire-dependent ecosystems and commercial forests (Mutch 1994, USDA Forest Service 1994, USDI 1995, Bell et al. 1995). The USDA Forest Service has set a goal of burning 1.2 million hectares per year by the year 2010 (Bell et al. 1995). Wise allocation of prescribed fire resources will require a solid baseline assessment of current activity and an understanding of the barriers to implementation of burning programs. Despite its ecological benefits, prescribed burning is being increasingly scrutinized and regulated as a source of air pollution (Sandberg 1978), traffic hazards (Mobley 1990), and escaped wildfire (Mobley 1985, Hoover 1989, Craig 1990, Cleaves and Haines 1997).
This report summarizes the results of a survey conducted to quantify prescribed burning activity on Forest Service lands, and to identify resource objectives and barriers to increased burning. No comprehensive assessment of the area treated by prescribed burning has been made; and Forest Service administrative units only recently have begun to consolidate their estimates of prescribed burning needs. Such information, as well as a characterization of the physical, social, legal, economic, and managerial factors that shape the burning programs on National Forests will be necessary to effectively develop expanded burning programs.
Analyses of prescribed burning activity levels, as well as resource objectives and constraints, were based on responses to a questionnaire mailed to Forest Service fuels management officers (FMO's) in December 1995. For the period 1985-1994, the FMO's were asked to provide estimates for the following variables: (1) acres burned annually and number of burns for each of four burn types--slash reduction, management-ignited burns in natural fuels, prescribed natural fires, and brush, range and grassland burns (Slash reduction includes burns to reduce debris from logging, road construction or natural events. Management-ignited fire is understory burning in an established stand. Prescribed natural fires are those ignited by lightning or spontaneous combustion. Brush, range, and grassland burns do not include fires for cropland management.) ; (2) major intended resource benefits or purpose of burns; (3) historic trends in and expectations for burned acreage by type of burn; (4) barriers to expanding the use of prescribed fire; and (5) annual acreage of prescribed burning needed to achieve resource management goals. The FMO's ranked resource objectives and constraints on a scale of 0 to 5 with 5 being most important.
We received completed surveys from 95 of the 114 FMO's contacted; and those responding units accounted for about 85 percent of the total National Forest System acreage, excluding Alaska. National forest-level estimates were aggregated into regional and national totals.
Activity Levels and Resource Objectives
The total prescribed fire area averaged 367,511 hectares per year. The Southern Region reported the highest annual average burned area at 175,686 hectares (Fig.1).
The total acreage treated was not evenly distributed by burn type. Management-ignited prescribed fires accounted for the most at 62.2 percent of the system total; followed by slash reduction (25.3 percent), brush and rangeland (8.3 percent), and prescribed natural fire (4.2 percent). Overall, the national forests conducted an average of 6,763 burns per year, of which 75 percent were for slash reduction and 20 percent were management-ignited burns in natural fuels. Accordingly, regions with significant slash burning acreage reported the most burns.
Fig.1. Annual prescribed burning area (ha) by U.S. Forest Service Region
The most important resource objective or purpose for burning was wildfire hazard reduction, followed by ecosystem management (using prescribed burning to reestablish natural fire intervals), game habitat enhancement, site preparation for reforestation, nongame habitat enhancement, control of competing vegetation in timber stands, threatened and endangered species habitat enhancement; insect and disease management; and rangeland improvement. The average burn size was 54 hectares. This varied from 17 hectares in the Pacific Southwest Region to 185 hectares in the Southern Region. The largest burns were prescribed natural fires (251 hectares) and smallest were slash burns (18 hectares). Management-ignited burns were the second largest(166 hectares) followed by brush and range burns (124 hectares). This relationship of relative burn size was similar among most regions. Estimates of burning levels needed to achieve management goals totalled 0.82 million hectares per year, more than twice the average achieved during the survey period. Desired acreage, as a percent of the acreage attained, ranged from 145 percent in the Northern Region to 672 percent in the Intermountain Region.
Trends in Burning Activity
Because of reductions in timber harvesting between 1985-1994, the slash burn acreage had decreased in more forests (60 percent) than any other burn type. Conversely, increasing fuel treatment budgets and greater emphasis on the use of prescribed fire for silviculture, ecosystem, and wildlife purposes resulted in a 76 percent increase in the number of forests using management-ignited burning. Prescribed natural fire levels remained fairly constant servicewide (62 percent), except in the Southwestern Region where there was a large increase. Brush and rangeland burns either increased (43 percent) or remained stable (44 percent) Servicewide.
Over the next ten years (1995 to 2004), estimated trends for all burn types range from a 57 percent chance of increase to a 15 percent chance of decrease. There is a 28 percent chance it will remain about the same. The likelihood for increasing management-ignited burns, prescribed natural fires, and brush and rangeland burns are 79, 66, and 51 percent, respectively. Conversely, there is only a 31 percent chance that slash burning will increase.
Barriers to Burning
The FMO's rated 14 factors on a 5-point "scale of importance," representing the degree to which each factor imposed a barrier to expanding the use of prescribed fire. The environmental law factor, which includes laws to protect water quality, endangered species, archaeological sites, and other resource values -- but does not include laws governing smoke management or protecting air quality -- received the highest mean rating (3.82). Environmental laws also include planning and evaluation procedures to be followed when conducting land management activities on Federal lands. Lack of adequate funding was the second most important factor, with a mean of 3.66. Also highly rated were: personnel (shortages of qualified professionals and technicians); narrow window (the prescription window for conducting burns); planning costs; public opinion; liability (for smoke intrusion and escaped fires); and regulations (air quality and smoke management laws). Barriers that received low ratings in all regions included: the use of alternative management practices, uncertainty about burning as an effective fuels management practice (such as effects on soil composition or tree growth), and the availability of insurance.
Fig.2. Prescribed burning operation in the Sierra Nevada, California.
Discussion and Conclusions
Prescribed burning is an important activity in the National Forest System. At about 364,225 hectares accomplished each year, it may be the most common planned disturbance, a distinction formerly held by timber harvesting. Changes are occurring quickly. For example, Forest Service fuel management budgets have increased substantially, from historic levels of about US$20 million, to US$60 million in 1997. The acreage of natural fuels burned each year has been increasing, for both management-ignited and prescribed natural fire. There is some uncertainty about the prescribed natural fire program; the use of prescribed natural fire is controversial and subject to conflicting political, physical, and managerial objectives.
The FMO's who responded to our survey confirmed the need for an increased use of fire. Less than half of the desired level is being met, although recent increases in appropriated funds has narrowed the gap. Barriers consist chiefly of environmental restrictions, funding shortfalls, and a shortage of available personnel.
The perceived importance of the environmental barrier may be due to a combination of factors: ambiguity in the application of regulatory standards, actual restrictions on burning practices, and reaction to the prospect of increasing regulation. Potential legal actions by interest groups or concerned citizens may also contribute to the importance of this factor. Although appropriated funds have increased since 1995, the availability of personnel for prescribed burning may become critical, especially with increasing competition from the wildfire control burden. Burning helps managers achieve a variety of resource objectives. The Forest Service prescribed burning program is linked to the future of many of its other programs, e.g., wildlife, threatened and endangered species, range, and ecosystem management.
Many respondents identified the shift from slash reduction burns to natural fuels burns as indicative of a trend towards fewer and larger burns. Although such a trend could have positive implications for per-acre costs, it might also could present problems in successfully managing the wildland/urban interface, sensitive species habitat, and other protected areas. The Forest Service officials who responded to our survey were optimistic about achieving resource goals, despite implementation barriers and cost constraints. The shortage of trained personnel and uncertainties about long-term funding are concerns that must be addressed if progress towards these goals is to continue. The burning seasons narrow window of opportunity makes it doubly important that managers have a well-trained and available workforce.
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From: Terry K. Haines and Jorge Martinez and David A. Cleaves
USDA Forest Service
Southern Research Station
Law and Economics Research Unit
USA - New Orleans, Louisiana
USDA Forest Service
USA - Washington D.C. 20090
IFFN No. 19