Prescribed Fire Research Articles

Width: An Indispensable Factor in Selection of Emergency Exit Door

Predicting evacuees' exit-door selection is important for architects and fire engineers. Existing models used in fire prescription and evacuation simulation assume that the distance from an evacuee to an exit door is the dominant geometric factor. However, evacuation validation studies and architectural theories suggest the existence of other factors. An exit-door-selection model was built in a virtual environment covering six geometric exit-door attributes. The impacts of these attributes were surveyed quantitatively using 187 participants. The results indicate that the attribute width is an indispensable factor in the selection. It is the strongest positive factor with the feasibility to control architectural design that can compete or balance with the negative attribute distance in exit-door selection.

Home range size and use by the long-nosed bandicoot (Perameles nasuta) following fire

Understanding how animals use available habitat and how disturbance events such as fire influence habitat use is crucial to wildlife management. Relationships between home-range size of long-nosed bandicoots (Perameles nasuta) and vegetation type and fire effects on food availability and vegetation cover were explored. Home ranges and movement of P. nasuta were mapped in burnt and unburnt vegetation using radio-tracking. Compositional analysis was used to study their habitat associations. In 2004, six months after wildfire, no significant relationships were found between home-range size and vegetation type. In 2005, there was a preference for dry and wet forest over heath and disturbed areas. In both years, in ranges that contained both burnt and unburnt vegetation, there was a preference for unburnt vegetation. Home-range size was positively related to the bodyweight of individuals. Fire did not significantly alter home-range size, but did influence the way animals used their home range. Dense understorey might provide vital shelter from predators, and may be particularly important after fire. Wildfire and prescribed burning are major forms of disturbance in many natural areas and this study suggests the importance to P. nasuta of retaining unburnt patches when conducting hazard-reduction burning.

Burning in Banksia Woodlands: How Does the Fire-Free Period Influence Reptile Communities?

Fire is an important management tool for both hazard reduction burning and maintenance of biodiversity. The impact of time since last fire on fauna is an important factor to understand as land managers often aim for prescribed burning regimes with specific fire-free intervals. However, our current understanding of the impact of time since last fire on fauna is largely unknown and likely dependent on vegetation type. We examined the responses of reptiles to fire age in banksia woodlands, and the interspersed melaleuca damplands among them, north of Perth, Western Australia, where the current prescribed burning regime is targeting a fire-free period of 8–12 years. The response of reptiles to fire was dependent on vegetation type. Reptiles were generally more abundant (e.g. Lerista elegans and Ctenophorus adelaidensis) and specious in banksia sites. Several species (e.g. Menetia greyii, Cryptoblepharus buchananii) preferred long unburnt melaleuca sites (>16 years since last fire, YSLF) compared to recently burnt sites (<12 YSLF). Several of the small elapids (e.g. the WA priority listed species Neelaps calonotus) were only detected in older-aged banksia sites (>16 YSLF). The terrestrial dragon C. adelaidensis and the skink Morethia obscura displayed a strong response to fire in banksia woodlands only. Highest abundances of the dragon were detected in the recently burnt (<7 YSLF) and long unburnt (>35 YSLF) banksia woodlands, while the skink was more abundant in older sites. Habitats from a range of fire ages are required to support the reptiles we detected, especially the longer unburnt (>16 YSLF) melaleuca habitat. Current burning prescriptions are reducing the availability of these older habitats.

The bark of eucalypt trees: habitat quality for arthropods and impact of fire.

The bark of eucalypt trees is a significant habitat attribute of forests and woodlands, with different bark types supporting varying populations of invertebrate and vertebrate fauna. Bark also contributes to fuel load in wildfires and hazard reduction burning, with a concomitant loss of habitat and modification of habitat resources. We compared the composition and abundance of tree trunk invertebrates inhabiting four eucalypt bark types and determined the impact of burning the bark on population abundance and community composition. Trees of four bark types (gum, box, stringybark, ironbark) were selected at three sites and arthropod traps placed on burnt and unburnt trees of each type. Traps were left in place for 12 days and arthropod preferences for the four bark types (burnt and unburnt) were analysed. The total number of arthropods differed between bark types, with stringybark and ironbark supporting the largest numbers of invertebrates and the most diverse communities. Burnt stringybark and gum bark had reduced arthropod abundance compared to unburnt bark. The study highlights an ecological consequence of fire on an aspect of invertebrate habitat, with flow-on effects for vertebrates, that should be considered in fire management, as greater areas of land are subject to frequent hazard reduction burning in eastern Australia.

PiroPinus: A spreadsheet application to guide prescribed burning operations in maritime pine forest

The efficient, sustainable and safe use of prescribed burning is based on quantitative application guidelines. PiroPinus was conceived for operational support to line-ignited, hazard-reduction burning in maritime pine ( Pinus pinaster) forest, but can be used as a modelling tool for surface fire behaviour in general. PiroPinus rests on a sound empirical foundation and links the fire environment (fuel, weather, terrain), fire behaviour characteristics, and fire effects on fuels and trees. PiroPinus produces burn prescriptions and predictions that match site-specific treatment objectives and environmental conditions, and enables post burn assessments of treatment effectiveness and impact. Implementation in Microsoft Excel facilitates improvement, expansion and custom modification.

Plains Prickly Pear Response to Fire: Effects of Fuel Load, Heat, Fire Weather, and Donor Site Soil

Plains prickly pear (Opuntia polyacantha Haw.) is common throughout the Great Plains and often becomes detrimental to agricultural production on noncultivated lands. We examined direct fire effects on plains prickly pear and mechanisms of tissue damage to facilitate development of fire prescriptions. Cladodes from clones on three soils (claypan, gravelly, silty) were subjected to fire with two weather conditions (moderate, severe) at four fuel loads (1500, 3000, 4500, and 6000 kg ?ha 21 ) and a nonburned control. Fire was simulated with field-collected grass, and heat was measured using thermocouples at the soil surface and 8 cm above. Plants were maintained in a greenhouse and monitored for cladode mortality or growth. Cactus response to fire was examined in a field experiment with four nonburned and four summer-burned 0.75-ha plots. Some plants from each treatment sprouted new cladodes. Donor site soil and fire weather effects were limited to mass of new sprouts as they interacted with fuel load. Fire under any condition reduced cactus mass and survival. Reduction in cactus mass increased from 42% with 1500 kg ?ha 21 to 92% with fuel loads of 3000 kg ?ha 21 or more. Fuel load, duration of heat, maximum temperature, and degree-seconds were each positively related to mortality, but duration of heat greater than 60uC was the best predictor. Plant mortality was 15% in the field, but number of live cladodes was initially reduced 91%. After one year, number of live cladodes in burned plots was 43% of that in nonburned plots because burned plants sprouted more new cladodes than nonburned plants. Insect and browsing damage occurred on 83% of cladodes in burned plots and only 8% for nonburned plots. Lack of fire weather effects suggests prickly pear control can be achieved under broad fire prescriptions, given the amount of combustible fuel is adequate.

Impacts of fire suppression on space use by Mexican fox squirrels

Human suppression of fire has resulted in altered species composition and dense forest stands across the western United States. Accumulation of understory shrubs makes forests vulnerable to catastrophic fire and can impact animal use, whereas fire prescription can ameliorate negative impacts of suppression. We used radiotelemetry to determine patterns of habitat use and survival of Mexican fox squirrels (Sciurus nayaritensis chiricahuae) in fire-suppressed and fire-prescribed areas of the Chiricahua Mountains, Arizona. Core areas of squirrels within fire-suppressed areas were larger and contained more understory shrubs than core areas of squirrels in fire-prescribed areas. Shrub cover and canopy heterogeneity influenced core-area size and distance traveled, and squirrels that were depredated traveled farther than conspecifics that survived, but shrub cover and canopy heterogeneity were not directly associated with squirrel survival. Suppression-induced increases in understory vegetation might force squirrels to travel greater distances to meet energetic requirements and thereby increase predation risk. Retention of mature forested canyons and restoration of natural fire regimes will be important for the persistence of Mexican fox squirrels.

Growing-Season Disturbance in Tallgrass Prairie: Evaluating Fire and Grazing on Schizachyrium scoparium

Historically, fire occurred throughout the year in the Great Plains, but current fire prescriptions are generally limited to the dormant season because of concerns for potential damage to fire-sensitive herbaceous plant species deemed economically and ecologically important. We coupled a field-based study and a controlled greenhouse study to quantify the effects of fire season and herbivory on plant species composition, along with survival and productivity of little bluestem (Schizachyrium scoparium [Michx.] Nash). We investigated the effects of both dormant and growing-season fire interacting spatially with grazing on plant community composition in a 10-yr field study. We also examined the influence of both growing-season fire and clipping on survival and aboveground and belowground production of potted little bluestem plants at multiple ages in a controlled greenhouse experiment. Plants were grown to 6 wk, 10 wk, or 18 wk, then either burned or clipped, followed by as many as two successive clipping events. Plant community composition and canopy cover of little bluestem were unaffected by season-of-burning in the field study. Survival of individual little bluestem seedlings in the greenhouse study was dependent primarily on plant age, with nearly 100% survival among all burning and clipping treatments at 18 wk old. Burning or clipping once did not decrease survival compared to seedlings that were not burned or not clipped, and burning followed by clipping did not decrease survival over multiple clipping events among 6-wk-, 10-wk-, or 18-wk-old plants. Both aboveground regrowth and belowground biomass increased with burning, but clipping reduced regrowth. Based on both field and greenhouse experiments, we conclude that little bluestem is well adapted to growing-season disturbance. Moreover, little bluestem responds more positively to growing-season fire than to clipping. Our results provide no evidence that little bluestem should be deferred from grazing after burning as part of a rangeland management strategy.

Influence of herbicides and felling, fertilization, and prescribed fire on longleaf pine growth and understory vegetation through ten growing seasons and the outcome of an ensuing wildfire

Restoring longleaf pine (Pinus palustris Mill.) over much of its original range requires artificial regeneration. In central Louisiana, USA, two fertilization levels—No (NF) or Yes (F-36 kg/ha N and 40 kg/ha P) in combination with three vegetation treatments—Check, four prescribed fires (PF), or multi-year vegetation control by herbicidal and mechanical means (IVM) were applied to container-grown longleaf pine plantings in a grass savanna. After 10 years, P concentration in longleaf pine foliage was less on NF plots than F plots, but fertilization did not significantly affect tree stature. Survival was greater on NF plots than F plots, and so, NF plots were more productive (NF—63 m3/ha and F—45 m3/ha). Pine trees on IVM plots (37 dm3/tree) were significantly larger than on Check and PF plots, which averaged 17 dm3/tree. Survival was better on IVM plots (88%) than PF plots (78%), which was better than Checks (58%). Consequently, IVM plots were most productive (99 m3/ha), followed by PF plots (44 m3/ha), and lastly Checks (28 m3/ha). PF plots had greater grass cover (38%) than Check and IVM plots, which averaged 5%, whereas PF and IVM plots had less understory arborescent cover (an average of 25%) than Checks (91%). A wildfire in March 2007 reduced pine survival by 22, 14, and 1 percentage points on IVM, Check, and PF plots, respectively. Seven months later, longleaf pine production had decreased to 92 m3/ha on IVM plots while increasing to 55 m3/ha on PF plots and 30 m3/ha on Checks. Overall, the wildfire rejuvenated the herbaceous plant community. Grass cover on Check and IVM plots averaged 20% while grass cover on PF plots was 36%. Forb cover increased on all treatments from 2% before the wildfire to 13% seven months after the wildfire. Understory arborescent cover decreased on Checks to 62% but increased slightly on PF and IVM plots and averaged 30%.

Effects of different site preparation methods on soil carbon and nutrient removal from Eastern beech regeneration sites in Turkey's Black Sea region

In terms of wood production, eastern beech ( Fagus orientalis Lipsky) is one of the most important Turkish tree species. The main forestry operation in the Black Sea region (BSR) is the harvesting of natural beech stands. These stands are naturally regenerated. A dense rhododendron ( Rhododendron spp.) understorey prevents eastern beech ( F. orientalis Lipsky) seed-tree regeneration in the Turkish BSR. Our study objective was to investigate the forest ecosystem effects of different woody vegetation control methods on forest floor organic matter (OM), soil organic carbon (SOC), soil physical and chemical properties and nutrients on beech regeneration sites in this region. In 2006, rhododendrons were cleared from treatment plots using hand labour by grubbing (GR), prescribed fire (PF), or machine preparation (MP) with a rake-equipped bulldozer. Untreated plots served as controls. The woody vegetation understorey, forest floor OM and mineral soil (0–20 cm) were sampled, and their biomass, SOC and nutrient content were estimated for each treatment. While effective in preparing sites for beech regeneration, the MP treatment resulted in highly compacted soil (mean = 1.5 g cm −3) compared to the other treatments (1.1 g cm −3). It also showed the largest ecosystem losses of C (−45%), N (−30%), and P (−55%) from the forest floor and mineral soil (0–20 cm). Furthermore, the MP treatment induced large ecosystem losses of soil K (−72%) and Ca (−58%). Both the GR and PF treatments increased soil pH and cation exchange capacity (CEC) relative to the controls, while their ecosystem C (−25%) and N (−22%) losses were moderate. In conclusion, the MP site preparation method removes more OM and soil nutrients, resulting in a lower soil CEC capacity compared to the other rhododendron control practices, including prescribed fire. Using heavy machinery during site preparation compacts the soil, increasing soil density to a level that may restrict plant growth. In contrast, grubbing and prescribed fire increase the soil pH and plant nutrient availability without compacting the soil. Therefore, these two methods should be promoted as effective and sustainable rhododendron control techniques for long-term productivity of eastern beech forests.

Isolating the lightning ignition regime from a contemporary background fire regime in east-central Florida, USA

Anthropogenic influences have altered most fire regimes. Fire management programs often try to mimic natural fire regimes to maintain fuels and sustain native fire-dependent species. Lightning is the natural ignition source in Florida, substantiating the need for understanding lightning fire incidence. Sixteen years of lightning data (1986–2003, excluding 1987 and 2002 due to missing data) from the NASA Cloud to Ground Lightning Surveillance System and fire ignition records were used to quantify the relationship between lightning incidence and ignitions on Kennedy Space Center, Merritt Island National Wildlife Refuge, and Cape Canaveral Air Force Station. There were 230 lightning fires with an average of 14 ignitions per year, primarily in July, and only one winter ignition. Precipitation influenced the efficiency of lightning ignitions, particularly July precipitation. We found that negative polarity strikes caused the majority of ignitions. Pine flatwoods was ignited more frequently than expected given equal chance of ignition among landcover types. About half (51%) of detected fires were instantaneous ignitions and the other 49% were delayed an average of 2 days. This information is useful for paramaterizing fire regime models and for mimicking the natural fire regime through fire prescriptions on these properties and throughout the southeastern United States. These methods may be useful in fire-maintained systems globally.

Experimental burning changes the quality of fallen timber as habitat for vertebrate and invertebrate fauna: implications for fire management

Context Fallen timber is a key habitat feature in forests and woodlands for vertebrate and invertebrate fauna, and is either consumed or left partially burnt after the passage of fire. This impact on habitat quality assumes significance because increasing areas of land are subject to frequent hazard-reduction burning and wildfire in eastern Australia. Aims We test here whether partially burnt or charred fallen timber is employed as habitat to the same extent as unburnt fallen timber. Methods Vertebrate and invertebrate abundance beneath burnt and unburnt fence posts was monitored for 13 months in unburnt forest and forest burnt by a wildfire. Key results Both vertebrate and invertebrate fauna made significantly less use of charred refuges. In most taxa, twice as many animals occurred under unburnt as under burnt artificial timber refuges, ant nests being the exception. Fauna made greater use of experimental refuges in burnt forest. Key conclusions Partially burnt fallen-timber refuges, where the log surface is left charred, are inferior habitat for fauna. Habitat quality in burnt forest may be enhanced by introducing fallen timber. Implications The study highlights an ecological consequence of fire for habitat quality, whether through wildfire or hazard-reduction burning, which should be considered in fire management.

Book Review: Conducting Prescribed Fires — A Comprehensive Manual, John R. Weir

Book Review: Conducting Prescribed Fires — A Comprehensive Manual, John R. Weir. Texas A&amp;M University Press, College Station, Texas, USA (2009).

Urban edge effects in the Blue Mountains, New South Wales: implications for design of buffers to protect significant habitats

Urban edge effects can have an adverse impact on native flora and fauna in the adjoining bushland. We surveyed edge effects at sites in the Blue Mountains where the urban area is separated from bushland by a perimeter road. Common edge effects included weed invasion, physical disturbance of the vegetation and soil, incidental rubbish, dumped rubbish, dumped plant material, tree felling/lopping/ringbarking and visits from domestic dogs. Uncommon edge effects included recent hazard reduction burns, bushrock collection, and poor tree health (dieback not associated with fires). The maximum extent of obvious edge effects (all types combined) varied between sites, from 9 m to 60 m from the edge of the road. At most sites (77%), edge effects were restricted to distances of 40 m or less into the bushland, but a significant number of sites (23%) had more extensive edge effects. Sites with extensive weed invasion were associated with older housing, suggesting that weed invasion will increase over time at sites adjacent to younger housing. Weed invasion frequently extended further than 60 m into the bushland along drainage lines and tracks, especially the former, but these were not included in the measurements. Edge effects were more extensive on flatter topography than downslope of housing, apparently because the former is subject to more intensive use by local residents. The actions of local residents have a major influence on edge effects, and are responsible for much of the variability observed between sites. The findings of this study are consistent with previous studies of edge effects around Sydney and elsewhere. Based on the results of the study, we recommend that a buffer of native vegetation at least 60 m wide should be retained around significant flora and fauna habitats to protect them from edge effects. Additional management actions are required to control vegetation degradation along drainage lines.

Summary of the 2009 Wisconsin Prescribed Fire Conference

Summary of the 2009 Wisconsin Prescribed Fire Conference

Prescribed fire, Nicholasville, Kentucky, 2005

Prescribed fire, Nicholasville, Kentucky, 2005

Developing an Adaptive Management approach to prescribed burning: a long-term heathland conservation experiment in north-west Italy

Calluna vulgaris-dominated heathlands are globally important habitats and extremely scarce outside of north-west Europe. Rotational fire, grazing and cutting by local farmers were dominant features of past heathland management throughout Europe but have been abandoned, altering the historical fire regime and habitat structure. We briefly review research on Calluna heathland conservation management and provide the background and methodology for a long-term research project that will be used to define prescribed fire regimes in combination with grazing and cutting, for management of Calluna heathlands in north-west Italy. We outline the ecological and research issues that drive the fire experiment, making explicit the experimental design and the hypotheses that will be tested. We demonstrate how Adaptive Management can be used to inform decisions about the nature of fire prescriptions where little formal knowledge exists. Experimental plots ranging from 600 to 2500 m2 are treated according to one of eight alternative treatments (various combinations of fire, grazing and cutting), each replicated four times. To date, all treatments have been applied for 4 years, from 2005 to 2008, and a continuation is planned. Detailed measurement of fire characteristics is made to help interpret ecological responses at a microplot scale. The results of the experiment will be fed back into the experimental design and used to inform heathland management practice in north-west Italy.

Can prescribed fire be used to maintain fuel treatment effectiveness over time in Black Hills ponderosa pine forests?

We determine the time frame after initial fuel treatment when prescribed fire will be likely to produce high enough mortality rates in ponderosa pine ( Pinus ponderosa var. scopulorum Dougl. ex Laws.) regeneration to be successful in maintaining treatment effectiveness in the Black Hills of South Dakota. We measured pine regeneration in disturbed stands and young pine growth rates to estimate the susceptibility of pine regeneration to prescribed fire with time since initial treatment. We also determined surface fuel accumulation rates for stands after prescribed fire to help estimate likely fire behavior in maintenance prescribed fire. Given our estimates of regeneration density and tree size, and likely fire behavior, we then used small pine tree mortality—fire effect relations to estimate the effects of prescribed fire on developing understory pine at specific times since initial treatments. Fuel treatments in ponderosa pine forests will lose their effectiveness within 10–20 years if regeneration densities are not controlled. The ability to successfully use prescribed fire to maintain low regeneration densities is dependent on seedling/sapling size and the frequency of burns. Current prescribed fire prescriptions and fuel loads are adequate to maintain low densities of ponderosa pine seedlings (<1 m tall) if burns occur every 10 years. If burn intervals exceed 15 years, regeneration can attain sizes that reduce susceptibility to prescribed fire under typical operational weather conditions. After 20–25 years, ponderosa pine can reach sizes that will require flame lengths that exceed 2 m to obtain significant mortality. Achieving these flame lengths will require burning under drier weather conditions to allow coarse woody debris (CWD) consumption to contribute to the fire intensity. Alternatively, managers can augment sites with activity fuels to increase fine fuel loadings to achieve flame lengths that will increase sapling susceptibility to fire, while burning when CWD fuel moistures are high to limit the potential for extreme fire behavior. While the flames might kill sapling-sized trees, mature overstory trees could still maintain resiliency to fire.

Forest bioenergy system to reduce the hazard of wildfires: White Mountains, Arizona

In an innovative effort, the USDA Forest Service is planning to reduce the long-term threat of catastrophic wildfires by inaugurating a series of forest thinnings for bioenergy. The start-up project is in the Nutrioso area of the Alpine Ranger District, Apache-Sitgreaves National Forest. ‘‘The Nutrioso Wildland/Urban Interface Fuels Reduction Project’’, under the authority of the Healthy Forest Restoration Act of 2003, addresses the existing condition of the forest, defines the desired condition of the forest, and proposes actions that will result in a healthier forest and a reduced risk from wildfire. This project is part of larger-scale, small-diameter tree thinning covering an area of 607 km 2 over a 10-yr period. Although the Nutrioso Project encompasses 213 km 2 of mixed ownerships, only National Forest lands (79%) will be treated. A variety of thinning and fire prescriptions have been established depending on slopes, road access, and distance from private land. The mostly small-diameter (o12 cm) trees in ponderosa pine and mixed conifer stands are being removed under a ‘‘Stewardship Contract’’ for utilization in small power plants (o3 MW), and a wood-heating pellet manufacturing facility. The outlet for the wood fuel pellets is the growing market for house and business heating, and co-generation fuel in a 615 MW coal-fired power station. This paper examines the scope, costs, and environmental trade-offs of this pioneering and remarkably successful effort in forest bioenergy in the southwestern USA. Published by Elsevier Ltd.

How to Build Cost-Effective Skid-Sprayers for Prescribed Burning

April 2007 The decline of grassland and savanna ecosystems due to woody plant encroachment has led to an increase in restoration efforts largely focused on reintroducing an effective fi re regime. However, reintroduction of fi re into Texas ecosystems has not been easy, especially in the Edwards Plateau region, where fi re has been suppressed since the development of the livestock industry. Implementation of an effective prescribed burning program requires rancher and landowner education and cooperation; it also requires prescribed fi re training, sharing of proper equipment, reduced liability, and the ability of ranchers to gain experience on the fi re line as well as writing burn plans and managing prescribed fi res. Equally important in getting a sustainable fi re program started is the ability to conduct prescribed burns under a wide range of environmental conditions (for example, conducting prescribed fi re during burn bans). The formation of prescribed burn associations, such as the Edwards Plateau Prescribed Burn Association, has provided a framework for ranchers and other landowners to collectively manage all of these factors with the end result of a substantial increase in prescribed fi re on Texas rangelands.1