Prescribed Fire Research Articles

Acceptability of Smoke From Prescribed Forest Burning in the Northern Inland West: A Focus Group Approach

Focus groups were used to gauge tolerance of smoke from broadcast prescribed forest burning in the wildland-urban interface of the northern Inland West. Focus group participants worked through issues surrounding prescribed burning as a management tool to determine if the origin of smokemade a difference in the acceptance of that smoke. Participant responses across five different population sectors suggest that prescribed forest burning could be applied as a forest management tool with a well-informed public and that establishing and maintaining a dialogue with the publicmay be the most important part of any fire prescription.

Factors controlling seedling germination after fire in Mediterranean gorse shrublands. Implications for fire prescription

In Western Mediterranean areas, fires are frequent in forests established on old croplands where woody resprouting species are scarce and post-fire regeneration is limited to obligate-seeder species, such as Mediterranean gorse ( Ulex parviflorus), that accumulate a great deal of fine dry fuel, increasing the risk of other severe fires. Under these conditions, fuel control techniques are required in order to prevent fires of high intensity and severity and the subsequent economic and ecological damage. Prescribed fires present an alternative to fuel control, and recent studies demonstrate that, under optimum climatic conditions, fire-line intensity values fall within the limits of those recommended for fire prescription. However, a better understanding of the consequences of fire on the regeneration of vegetation is needed in order to evaluate the suitability of prescribed fires as a technique for fuel reduction in Mediterranean gorse ecosystems. This paper analyses the factors controlling seedling germination after fire to make an evaluation from an ecological perspective of whether fire prescription is a suitable technique for fuel control in mature Mediterranean gorse shrublands. The results show that small differences in the composition of vegetation play a decisive role in fire behaviour, and have a decisive influence on the system's capacity for regeneration. Fire severity is low in mixed Mediterranean gorse communities with a low continuity of dead fine fuel (including Cistus sp., Rosmarinus sp., etc.) and fire creates a wide range of microhabitats where seedling emergence is high. In contrast, where U. parviflorus is more dominant, fire severity is higher and the regeneration of vegetation could be hindered. Our conclusions suggest that detailed studies of the composition of plant communities are required in order to decide whether prescribed burning should be applied.

Examining fire behavior in mesquite - acacia shrublands

The vegetation of South Texas has changed from mesquite savanna to mixed mesquite–acacia (Prosopis–Acacia) shrubland over the last 150 years. Fire reduction, due to lack of fine fuel and suppression of naturally occurring fires, is cited as one of the primary causes for this vegetation shift. Fire behavior, primarily rate of spread and fire intensity, is poorly understood in these communities, so fire prescriptions have not been developed. We evaluated two current fire behavior systems (BEHAVE and the CSIRO fire spread and fire danger calculator) and three models developed for shrublands to determine how well they predicted rate of spread and flame length during three summer fires within mesquite–acacia shrublands. We also used geostatistical analyses to examine the spatial pattern of net heat, flame temperature and fuel characteristics. The CSIRO forest model under-predicted the rate of fire spread by an average of 5.43 m min−1 and over-predicted flame lengths by 0.2 m while the BEHAVE brush model under-predicted rate of spread by an average of 6.57 m min−1 and flame lengths by an average of 0.33 m. The three shrubland models did not consistently predict the rate of spread in these plant communities. Net heat and flame temperature were related to the amount of 10-h fuel on the site, but were not related to the cover of grasses, forbs, shrubs, or apparent continuity of fine fuel. Fuel loads were typical of South Texas shrublands, in that they were uneven and spatially inconsistent, which resulted in an unpredictable fire pattern.

Selective control of rangeland grasshoppers with prescribed fire

Grasshoppers (Orthoptera: Acrididae) are considered among the most damaging rangeland pests, but are necessary for the survival of many wildlife species. Most grasshoppers species are innocuous, but control with insecticides is non-discriminatory among species. The objectives were to evaluate the effects of prescribed burning on the abundance and biomass of grasshoppers and to determine if species could be selectively controlled with prescribed fire. Twenty-four, 4-ha sites were selected in a sand sagebrush-mixed prairie near Woodward, Okla. and blocked by pasture. Plots were randomly assigned fall-, spring-, or nonburned treatments within block with 4 replications per treatment for each of 2 years. Grasshopper biomass and abundance were sampled in late July and early August by sweeping with canvas beating nets. Specimens were weighed to the nearest 0.1 mg and identified to species. Fire treatments had no effects on the total abundance or biomass of grasshoppers across species, with about 10 grasshoppers weighing 4,090 mg per 150 sweeps. Fire effects on the 4 most common species were variable and could be explained by the biology of the insects. Melanoplus bowditchi and M. flavidus were unaffected by fire treatment. Hesperotettix viridis is sensitive to damage to its host plants and was reduced about 88% by fire in either season. Ageneotettix deorum abundance was 65% lower on fall-burned plots. We hypothesize the reduction occurred because the species’ eggs are laid near the soil surface and exposed to the heat of passing fire. Fire prescriptions may be developed to target species-specific vulnerabilities and reduce pest grasshoppers while maintaining the food base for grasshopper predators.

Selective control of rangeland grasshoppers with prescribed fire

Grasshoppers (Orthoptera: Acrididae) are considered among the most damaging rangeland pests, but are necessary for the survival of many wildlife species. Most grasshoppers species are innocuous, but control with insecticides is non-discriminatory among species. The objectives were to evaluate the effects of prescribed burning on the abundance and biomass of grasshoppers and to determine if species could be selectively controlled with prescribed fire. Twenty-four, 4-ha sites were selected in a sand sagebrush-mixed prairie near Woodward, Okla. and blocked by pasture. Plots were randomly assigned fall-, spring-, or non-burned treatments within block with 4 replications per treatment for each of 2 years. Grasshopper biomass and abundance were sampled in late July and early August by sweeping with canvas beating nets. Specimens were weighed to the nearest 0.1 mg and identified to species. Fire treatments had no effects on the total abundance or biomass of grasshoppers across species, with about 10 grasshoppers weighing 4,090 mg per 150 sweeps. Fire effects on the 4 most common species were variable and could be explained by the biology of the insects. Melanoplus bowditchi and M. flavidus were unaffected by fire treatment. Hesperotettix viridis is sensitive to damage to its host plants and was reduced about 88% by fire in either season. Ageneotettix deorum abundance was 65% lower on fall-burned plots. We hypothesize the reduction occurred because the species' eggs are laid near the soil surface and exposed to the heat of passing fire. Fire prescriptions may be developed to target species-specific vulnerabilities and reduce pest grasshoppers while maintaining the food base for grasshopper predators.

The effects of a low-intensity fire on small mammals and lizards in a logged, burnt forest

This study summarises the results of a patchy, low-intensity hazard-reduction burn on the small mammals and lizards of Mumbulla State Forest and Biamanga National Park. About half of the study sites in the patchwork of alternate logging regrowth and unlogged forest had been burnt in April 1999. Prior to burning (winter 1998), there were significantly more Antechinus agilis in those north-west-facing sites that burnt in 1999, than in the south-east sites that burnt. By 15 months post-burning this trend had reversed, with more A. agilis in the burnt south-east sites. In contrast, burning had an initially positive effect on the abundance of Rattus fuscipes, with significantly more in the burnt south-east than burnt north-west sites four months post-burning compared with 1998 (pre-burning). This influence of aspect may be attributable to the fact that fires generally burn more intensely on the drier north-west slopes, removing more of the leaf litter and vegetative cover and making post-fire conditions harsher. Antechinus swainsonii became extremely scarce in the forest after the burning. Twenty months post-burning (summer 2000), there were significantly more Lampropholis delicata in the unburnt sites than in the burnt sites compared with 1999 (10 months post-burn). Lampropholis guichenoti were affected to a much lesser extent and recovered quickly, and Eulamprus heatwolei were generally unaffected by the burning. The hazard-reduction burn came 19 years after a high-intensity bushfire and logging operation in this forest. The results of the two fires were similar for the two Antechinus species and the Eulamprus species but contrasted for the other species. Hazard-reduction burning is widespread and accepted as a management tool and, following the New South Wales bushfires of 1994–95 and 2001–02, will probably increase in use. Our results, however, suggest that the biodiversity impacts of burning are complex and multidirectional, posing a significant challenge to conservation managers.

Season of Burn Influences Fire Behavior and Fuel Consumption in Restored Shortleaf Pine–Grassland Communities

AbstractPine forests of southeastern United States have been burned primarily in the dormant season to accomplish silvicultural objectives, but with increased emphasis on ecosystem restoration fires are now prescribed in other seasons. We observed fire behavior during both growing season and dormant season prescribed fires in shortleaf pine (Pinus echinata) stands managed as pine–grassland communities for the endangered Red‐cockaded Woodpecker (Picoides borealis). Fuel beds for dormant season fires were characterized by lower amounts of live fuels, higher amounts of 1‐hr time lag fuel and a greater total fuel load than growing season fires. Fuel consumption and percent of the total fuels consumed was greater in dormant season fires than in growing season fires. Fireline intensity, heat per unit area, reaction intensity, and rate of spread were greater in dormant season fires than in growing season fires. Lower fire intensity in growing season fires was possibly a function of lower amounts of 1‐hr time lag fuels, higher amounts of live herbaceous fuels, and possibly a less porous fuel bed. Additionally, growing season fires had lower heat per unit area and reaction intensity and slower rates of spread. The Keetch‐Byram drought index (KBDI) did not provide a good index for potential fire behavior on our drought‐prone sandy loam soils. KBDI during growing season fires averaged over four times greater than during dormant season fires, but fire intensity was greater in dormant season fires. Low KBDI values may be misleading and give a false sense of security for dormant season fire prescriptions on sandy loam soils because the duff layer may dry more quickly as a result of inherent low water holding capacity. High KBDI values may result in prescribed burns being canceled because of conditions that are erroneously perceived to be outside the prescription window. We caution against over‐reliance on KBDI as a determining factor for conducting prescribed burns on areas with sandy or sandy loam soils.

MCE-RISK: integrating multicriteria evaluation and GIS for risk decision-making in natural hazards

During the past two decades there have been a wide range of applications for decision-making linking multicriteria evaluation (MCE) and geographic information systems (GIS). However, limited literature reports the development of MCE-GIS software, and the comparison of various MCE-GIS approaches. This paper introduces an MCE-GIS program called MCE-RISK for risk-based decision-making. It consists of a series of modules for data standardisation, weighting, MCE-GIS methods, and sensitivity analysis. The program incorporates different MCE-GIS methods, including weighted linear combination (WLC), the technique for order preference by similarity to ideal solution (TOPSIS), and compromise programming (CP), enabling comparisons between different methods for the same decision problem to be made. An example of decision-making for determining priority areas for a bushfire hazard reduction burning is examined. After implementing the alternative MCE-GIS methods, and comparing final outputs and the computational difficulty involved in the analysis, WLC is recommended. Some caveats on using MCE-GIS methods are also discussed. Although the development of MCE-RISK and its application reported in this paper are specific to risk-based decision-making in natural hazards, the program can be used for other environmental decision applications, such as environmental impact assessment and land-use planning.

Montane Rattlesnakes and Prescribed Fire

Montane Rattlesnakes and Prescribed Fire

Fire modeling and information system technology

This paper was presented at the conference ‘Integrating spatial technologies and ecological principles for a new age in fire management’, Boise, Idaho, USA, June 1999 Fire modeling and information system technology play an important supporting role in fuel and fire management. Modeling is used to examine alternative fuel treatment options, project potential ecosystem changes, and assess risk to life and property. Models are also used to develop fire prescriptions, conduct prescribed fire operations, and predict fire behavior. Fire models and information systems have greatly influenced fuel assessment methods. As an example, we examine the evolution of technology used to put Rothermel’s fire spread model into application. A review of fire and fuel modeling terminology is given, and the relationship between fire models and fuel models is explained. We review current fire modeling work and the influence that it will have on fuel characterization. Finally, we discuss opportunities and challenges involved in the use of advanced computers, the Internet, Geographic Information Systems (GIS), and remote sensing in fire and fuel management.

Mesoscale model forecasting as a tool for air pollution management: a case study of sustained smoke pollution over the Greater Sydney area

AbstractA mesoscale model has been applied over the Greater Sydney region to an air pollution episode resulting from fire hazard reduction burns from 12 to 14 April 1997. The episode was characterised by two distinct events in a period of sustained light winds, which included humid sea breezes and land breezes. The first event occurred early in the period when the atmospheric circulation involved either weak sea breezes or no sea breeze at the coast. Described here are the meteorological conditions associated with the inter‐regional transport of smoke from a prescribed, or hazard reduction, burn just north of Sydney, which concentrated smoke in the eastern part of the Sydney metropolitan area. The second event, which occurred late in the episode, was local in nature but was induced synoptically by the large‐scale airflow by a change in wind direction that transported smoke and fog over a major highway. Also described are the meteorological conditions that contributed to the disruption of a major highway caused by a multiple vehicle pile‐up just to the south‐west of Sydney later in the period. Numerical model simulations using the University of New South Wales (UNSW) NWP model, which used archived real‐time data, accurately predicted both the concentration of pollution in the eastern part of the Sydney metropolitan area in the first event and the hazardous smog formation and timing of the clearing south‐west wind change in the second event. Copyright © 2000 Royal Meteorological Society

Prescribed Fire Burns out of Control

Prescribed Fire Burns out of Control

Long‐term effects of frequent low‐intensity burning on ant communities in coastal blackbutt forests of southeastern Australia

AbstractPeriodic low‐intensity fire (hazard‐reduction burning) is a conspicuous management strategy in virtually all of Australia’s dry forest communities where it is primarily used to reduce fuel levels with the intention of minimising the extent and severity of wildfires. Little is known, however, about the effects of its repeated use on natural ecosystems over long periods of time. This study investigated the long‐term effects of frequent low‐intensity fire on forest ant communities by comparing frequently burnt sites with long‐unburnt control sites. While the richness of ant communities remained largely unchanged, the composition of assemblages differed substantially between treatments. Although frequent burning apparently resulted in the loss of a substantial number of species, the overall richness of frequently burnt areas was maintained by the addition of species not present on unburnt sites. These changes in species composition were accompanied by major changes in community organisation (structure) and were considered to be a response to altered habitat conditions, particularly litter biomass, vegetation structure and patterns of insolation at ground level. Appropriate fire prescriptions could therefore be applied to manipulate these habitat elements at a landscape scale to meet both management and conservation goals. A comparison of pitfall trapping and litter extraction techniques revealed the importance of a composite sampling strategy, with 22% of ant species detected only by litter extraction.

The Ethics of Prescribed Fire: A Notable Silence

The Ethics of Prescribed Fire: A Notable Silence

The Need for Consideration of Fire Behavior and Effects in Prescribed Burning

AbstractPrescribed burns are increasingly being used in ecological restoration and vegetation management. Despite the accumulation of scientific information on fire behavior and fire effects, however, in many cases fires are prescribed without consideration of such information and often simply because of evidence of past fires. Rather than basing fire management plans on ideas of the historical “natural” occurrence of fire, we present the case for fire management being based on the fire effects desired. Effective fire management and development of proper fire prescriptions require an understanding of fire processes and heat transfer that explain fire behavior characteristics, as well as an understanding of how fire behavior is coupled to specific fire effects. We provide a basic introduction to these concepts and processes, which will help in understanding the importance of having a more technical understanding of fire. The discussion includes the processes of heat transfer and the relative role of various fuel variables in these processes, as well as the concepts of fire intensity, rate of spread, fuel consumption, duff consumption, fire frequency, and the ecological effects associated with variation in these characteristics of fire behavior.

Prescribed Fire and Forest Pests: Solutions for Today and Tomorrow

Prescribed Fire and Forest Pests: Solutions for Today and Tomorrow

An advisory expert system for designing fire prescriptions

Prescribed fire is used to manipulate forest ecosystems to accomplish a variety of resource management objectives. To develop prescriptions that successfully achieve these objectives, managers use information from a variety of sources. These include results of scientific research and of their own experience. Much of the knowledge of expert practitioners has never been collected and made available to others. An expert system is being developed using rule-based inference and frame-based inheritance to integrate technical and heuristic information, and interpret it for application. Site data and the manager's objectives for treating the site with prescribed fire are inputs to the expert system. The system develops a fire prescription: ranges of acceptable fire effects, a description of the desired fire treatment, and a range of conditions under which to burn to achieve the desired treatments and effects. The system documents its results.

Short-Term Effects of Fuel Reduction Burning on Populations of Small Terrestrial Mammals

Small mammals (Rattus fuscipes, Mus musculus, Antechinus flavipes, Isoodon obesulus) were livetrapped for 18 months prior to fuel reduction burning (FRB) in dry sclerophyll forest dominated by Eucalyptus obliqua south of Adelaide. Although the fire prescription was hotter than that normally conducted for a FRB in this habitat, the fire was of low intensity, removing most of the litter and understorey but only singeing the canopy in a few places. Trapping continued for 16 months after the burn, when the study site was destroyed by a wildfire (Ash Wednesday, 16 February 1983). No animals were known to have died as a direct result of the FRB and little effect was observed on the population dynamics of A. flavipes. However, numbers of R. fuscipes declined precipitously in the 3 months following the FRB and remained at low levels with no summer recruitment of juveniles over the following 16 months (2 summers) as there had been in the summer prior to the FRB. No movements to unburned areas were recorded in either species after the FRB. There was no influx of M, musculus after the fire and there was no marked affect on the population of I. obesulus.

Mineral cycling processes and system stability in the eucalypt forest

The effects of disturbance on the stability of the eucalypt forest are considered in terms of Bormann and Likens' (1979) schema of reorganisation, aggradation, transition and steady state phases of secondary succession. The difficulties of making reliable estimates of ecosystem nutrient reserves are discussed against a background of anisotropic nutrient distribution, inadequate knowledge of the volume of soil effectively exploited by roots, and the limitations of existing techniques for soil chemical analysis. The relative significance of the atmosphere and parent material for the accumulation of nutrient reserves is outlined and the overriding importance of the latter on soil phosphorus capital in the eucalypt forest is emphasised. The capacity of forest ecosystems to restrict changes in the ionic concentration of percolating soil water is indicated and some important facets of nutrient dynamics are described. Spatial and temporal patterns of substrate availability and microbial activity greatly complicate the measurement of organic matter decomposition and nutrient flux on the forest floor. Adaptations of eucalypts potentially significant in mineral cycling are mentioned. The role of natural agents of disturbance as determinants of pattern in plant communities is indicated, and the effects of man-induced disturbances such as clearcutting, burning of logging debris, and hazard reduction burning are discussed in the context of biogeochemical cycling. The importance of close operational control of management practices is stressed, together with the need for appropriate measures of functional stability.

Costs of Hazard-Reduction Burning on Southern National Forests

Abstract Prescribed burning plans from national forests on the southern coastal plain provide sufficient data to estimate the costs of burns that were completed as planned. Estimated costs over a 4-year period in 1976 dollars ranged from $4.82 per acre for a 50-acre burn in a 12-year rough to $0.35 per acre for a 2,400-acre burn in a 4-year rough. Cost per acre was strongly influenced by the size of burn and age of rough (years since last burn).