scholarly journals The impact of aging on laboratory fire behaviour in masticated shrub fuelbeds of California and Oregon, USA

2016 ◽  
Vol 25 (9) ◽  
pp. 1002 ◽  
Author(s):  
Jesse K. Kreye ◽  
J. Morgan Varner ◽  
Jeffrey M. Kane ◽  
Eric E. Knapp ◽  
Warren P. Reed
Keyword(s):  
Tree Mortality ◽  
Management Practice ◽  
Fire Hazard ◽  
Woody Debris ◽  
Fuel Load ◽  
Fire Intensity ◽  
Fire Behaviour ◽  
Slow Combustion ◽  
The Impact ◽  
Over Time

Mastication of shrubs and small trees to reduce fire hazard has become a widespread management practice, yet many aspects of the fire behaviour of these unique woody fuelbeds remain poorly understood. To examine the effects of fuelbed aging on fire behaviour, we conducted laboratory burns with masticated Arctostaphylos spp. and Ceanothus spp. woody debris that ranged from 2 to 16 years since treatment. Masticated fuels that were 10 years or older burned with 18 to 29% shorter flame heights and 19% lower fireline intensities compared with the younger fuelbeds across three different fuel loads (25, 50 and 75 Mg ha–1). Older fuelbeds smouldered for almost 50% longer than the younger masticated fuelbeds. Fuel consumption was 96% in the two higher fuel load categories regardless of fuelbed age, whereas consumption was 77% in the lighter fuel load. Fire intensity in masticated fuels may decrease over time owing to particle degradation, but in dry environments where decomposition is slow, combustion of the remaining fuels may still pose risks for tree mortality and smoke production associated with protracted smouldering.

Fuel and fire characteristics in savanna - woodland of West Africa in relation to grazing and dominant grass type

2007 ◽  
Vol 16 (5) ◽  
pp. 531 ◽  
Author(s):  
Patrice Savadogo ◽  
Didier Zida ◽  
Louis Sawadogo ◽  
Daniel Tiveau ◽  
Mulualem Tigabu ◽  
...  
Keyword(s):  
Prescribed Burning ◽  
Management Tool ◽  
Fuel Load ◽  
Maximum Temperature ◽  
Fire Intensity ◽  
Fire Behaviour ◽  
Savanna Woodland ◽  
Vegetation Height ◽  
Average Maximum ◽  
Dominant Grass

Fuel characteristics, fire behaviour and temperature were studied in relation to grazing, dominant grass type and wind direction in West African savanna–woodland by lighting 32 prescribed early fires. Grazing significantly reduced the vegetation height, total fuel load, and dead and live fuel fractions whereas plots dominated by perennial grasses had higher values for vegetation height, total fuel load and the quantity of live fuel load. Although fire intensity remained insensitive (P > 0.05) to any of these factors, fuel consumption was significantly (P = 0.021) reduced by grazing, rate of spread was faster in head fire (P = 0.012), and flame length was shorter in head fire than back fire (P = 0.044). The average maximum temperature was higher (P < 0.05) on non-grazed plots, on plots dominated by annual grasses, on plots subjected to head fire, and at the soil surface. Lethal temperature residence time showed a nearly similar trend to fire temperature. Wind speed and total fuel load were best predictors of fire behaviour parameters (R2 ranging from 0.557 to 0.862). It can be concluded that grazing could be used as a management tool to modify fire behaviour, back fire should be carried out during prescribed burning to lower fire severity, and the fire behaviour models can be employed to guide prescribed early fire in the study area.

Behaviour and effects of prescribed fire in masticated fuelbeds

2011 ◽  
Vol 20 (8) ◽  
pp. 932 ◽  
Author(s):  
Eric E. Knapp ◽  
J. Morgan Varner ◽  
Matt D. Busse ◽  
Carl N. Skinner ◽  
Carol J. Shestak
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Fire Hazard ◽  
Weather Conditions ◽  
Flame Length ◽  
Fire Behaviour ◽  
Prescribed Burns ◽  
Rate Of Spread ◽  
Fuel Models

Mechanical mastication converts shrub and small tree fuels into surface fuels, and this method is being widely used as a treatment to reduce fire hazard. The compactness of these fuelbeds is thought to moderate fire behaviour, but whether standard fuel models can accurately predict fire behaviour and effects is poorly understood. Prescribed burns were conducted in young ponderosa pine (Pinus ponderosa Laws.) forests at two sites in northern California where the midstorey layer dominated by shrubs had been masticated. Surface fuels were raked from the base of a subset of trees before burning. Rate of spread and flame length were estimated for both backing and heading fires, soil heating measured with thermocouples and tree fire injury recorded. Standard fuel models often over-predicted rate of spread or under-predicted flame length. Custom models generally provided a better balance between the slow rates of spread and moderate flame lengths observed in prescribed burns. Post-fire tree mortality was most strongly associated with crown scorch and tree size; raking fuels from the base of trees did not improve survival. Under severe fire weather conditions, fire behaviour and effect models as well as observations from wildfires suggest that mastication may be more effective for moderating fire behaviour than reducing residual tree mortality. Treating masticated fuels with prescribed burns could potentially improve the resilience of stands to wildfire.

scholarly journals Applications of simulation-based burn probability modelling: a review

2019 ◽  
Vol 28 (12) ◽  
pp. 913 ◽  
Author(s):  
Marc-André Parisien ◽  
Denyse A. Dawe ◽  
Carol Miller ◽  
Christopher A. Stockdale ◽  
O. Bradley Armitage
Keyword(s):  
Wildland Fire ◽  
Fire Hazard ◽  
Fire Spread ◽  
Simulation Modelling ◽  
Fire Intensity ◽  
Fire Behaviour ◽  
Direct Examination ◽  
Burn Probability ◽  
Spatial Estimates ◽  
Hazard And Risk

Wildland fire scientists and land managers working in fire-prone areas require spatial estimates of wildfire potential. To fulfill this need, a simulation-modelling approach was developed whereby multiple individual wildfires are modelled in an iterative fashion across a landscape to obtain location-based measures of fire likelihood and fire behaviour (e.g. fire intensity, biomass consumption). This method, termed burn probability (BP) modelling, takes advantage of fire spread algorithms created for operational uses and the proliferation of available data representing wildfire patterns, fuels and weather. This review describes this approach and provides an overview of its applications in wildland fire research, risk analysis and land management. We broadly classify the application of BP models as (1) direct examination, (2) neighbourhood processes, (3) fire hazard and risk and (4) integration with secondary models. Direct examination analyses are those that require no further processing of model outputs; they range from a simple visual examination of outputs to an assessment of alternate states (i.e. scenarios). Neighbourhood process analyses examine patterns of fire ignitions and subsequent spread across land designations. Fire hazard combines fire probability and a quantitative assessment of fire behaviour, whereas risk is the product of fire likelihood and potential impacts of wildfire. The integration with secondary models represents situations where BP model outputs are integrated into, or used in conjunction with, other models or modelling platforms.

The effect of woody fuel characteristics on fuel ignition and consumption: a case study from a eucalypt forest in south-west Western Australia

2018 ◽  
Vol 27 (5) ◽  
pp. 363 ◽  
Author(s):  
J. J. Hollis ◽  
W. L. McCaw ◽  
M. G. Cruz
Keyword(s):  
Fuel Consumption ◽  
Fire History ◽  
Management Practices ◽  
Woody Debris ◽  
Fuel Load ◽  
Fire Behaviour ◽  
Ecological Processes ◽  
Eucalypt Forest ◽  
Eucalypt Forests ◽  
Fuel Particles

Coarse woody debris (>0.6 cm in diameter) is an important component of the fuel complex in Australian eucalypt forests, influencing both fire behaviour, smoke production and post-fire ecological processes. We investigated how physical characteristics of woody fuel affected ignition and consumption during an experimental fire where the fuel complex characteristics, fire weather and fire behaviour varied within a narrow range. Decay status, bark condition, arrangement, suspension and extent of charring were classified for 2866 coarse woody fuel particles. We used generalised linear model (GLM) analysis to explain ignition success and the extent of consumption of individual particles, with a focus on larger diameter fuels (>7.5 cm in diameter), which comprised 83% of the woody fuel load and 94% of the woody fuel consumed during the flaming and smouldering stages of combustion. Ignition success was best explained by a model that included fuel arrangement (a surrogate of fuel proximity), suspension and decay status. The extent of fuel consumption was greater for pieces in advanced stages of decay, but suspension (inversely related) and arrangement (directly related) also affected the outcome. Forest management practices, previous fire history and other natural disturbances are likely to influence the distribution of pre-fire diameters and suspension classes that characterise large woody fuels at a site, and will therefore influence woody fuel consumption. This has practical implications for quantifying heat release and atmospheric emissions from fires burning in forests with different management histories.

scholarly journals Fire behaviour in south-western Australian shrublands: evaluating the influence of fuel age and fire weather

2012 ◽  
Vol 21 (4) ◽  
pp. 385 ◽  
Author(s):  
Joseph B. Fontaine ◽  
Vanessa C. Westcott ◽  
Neal J. Enright ◽  
Janneke C. Lade ◽  
Ben P. Miller
Keyword(s):  
Accumulation Rate ◽  
Fire Hazard ◽  
Weather Conditions ◽  
Threshold Effect ◽  
Fire Frequency ◽  
Fire Intensity ◽  
Fire Weather ◽  
Fire Behaviour ◽  
Fire Propagation ◽  
Rate Of Spread

Fuel age (time since last fire) is often used to approximate fire hazard and informs decisions on placement of shrubland management burns worldwide. However, uncertainty remains concerning the relative importance of fuel age and weather conditions as predictors of fire hazard and behaviour. Using data from 35 experimental burns across three types of shrublands in Western Australia, we evaluated importance of fuel age and fire weather on probability of fire propagation (hazard) and four metrics of fire behaviour (rate of spread, fireline intensity, residence time, surface temperature) under moderate to high fire danger weather conditions. We found significant support for a threshold effect of fuel age for fire propagation but limited evidence for an effect of fuel age or fire weather on rates of spread or fireline intensity, although surface heating and heating duration were significantly related to fuel age and shrubland type. Further analysis suggested that dead fuel mass and accumulation rate rather than live fuels were responsible for this relationship. Using BEHAVE, predicted spread rates and intensities were consistently lower than observed values, suggesting further refinement is needed in modelling shrubland fire behaviour. These data provide important insight into fire behaviour in globally significant, fire-adapted shrublands, informing fire management and relationships between fire frequency and fire intensity.

The effect of mastication on surface fire behaviour, fuels consumption and tree mortality in pine flatwoods of Florida, USA

2015 ◽  
Vol 24 (4) ◽  
pp. 573 ◽  
Author(s):  
Jesse K. Kreye ◽  
Leda N. Kobziar
Keyword(s):  
Tree Mortality ◽  
Prescribed Burning ◽  
Fire Hazard ◽  
Fire Effects ◽  
Flame Height ◽  
Soil Conditions ◽  
Fire Behaviour ◽  
Pine Flatwoods ◽  
Southern Us ◽  
Limited Effectiveness

Mastication of understorey shrubs and small trees to reduce fire hazard has become a widespread forest management practice, but few empirical studies have quantified the effects of this mechanical treatment on actual fire behaviour and fire effects at the stand scale. We conducted experimental burns in masticated pine flatwoods with palmetto/gallberry understories, a common ecosystem of the Southern US Coastal Plain. Fire behaviour (flame height, rate of spread) and fire effects were compared between treated and untreated sites burned in the typical winter prescribed burning season. Mastication effectively reduced flame heights by 66%, but recovering shrubs (cover, height) influenced fire behaviour within six months following treatment, suggesting time-limited effectiveness. Trees had less crown scorch and bole char in masticated sites, but tree mortality was minimal on both treated and untreated sites. Consumption of masticated fuel was substantial across both treatments, but little duff was consumed under the moist soil conditions. When burning is conducted soon after treatment, mastication may effectively reduce fire behaviour in pine flatwoods sites, but the duration of treatment efficacy remains unclear.

Does season affect fire behaviour in the Cerrado?

2017 ◽  
Vol 26 (5) ◽  
pp. 427 ◽  
Author(s):  
Mariana Ninno Rissi ◽  
M. Jaime Baeza ◽  
Elizabeth Gorgone-Barbosa ◽  
Talita Zupo ◽  
Alessandra Fidelis
Keyword(s):  
Dry Season ◽  
Flame Height ◽  
Fuel Load ◽  
Fire Season ◽  
Fire Intensity ◽  
Fire Behaviour ◽  
Dead Biomass ◽  
Management Plans ◽  
Fire Exclusion ◽  
Fuel Moisture Content

Fire has played an important role in the plant dynamics and diversity of the Cerrado for millions of years. We evaluated fire behaviour in different fire seasons in areas of an open savanna, providing information for fire management plans. It has been hypothesised that early fires (May – end of the rainy season) will be less intense than those conducted in the middle and end of the dry season (July and October) owing to the amount of dead biomass accumulated. Therefore, we compared fire behaviour in early, mid- and late dry season, evaluating the main fire and environmental variables. Fire intensity was mainly influenced by the combination of dead fuel percentage and fuel load. Even though this combination was the best model to explain fire intensity variability, fire parameters (including fire intensity) did not differ between fire seasons. Flame height was best explained by dead fuel percentage + fuel moisture content, dead fuel percentage + fuel load and also by dead fuel percentage. Our study showed that, in areas with fire exclusion for 2 years, fire season did not influence fire parameters and fire behaviour and the main factors influencing fire intensity were the proportion of dead biomass and total fuel load.

scholarly journals Long-term changes in masticated woody fuelbeds in northern California and southern Oregon, USA

2020 ◽  
Vol 29 (9) ◽  
pp. 807
Author(s):  
Warren P. Reed ◽  
J. Morgan Varner ◽  
Eric E. Knapp ◽  
Jesse K. Kreye
Keyword(s):  
Tree Mortality ◽  
Fire Hazard ◽  
Fire Intensity ◽  
Fuel Loading ◽  
Fire Hazards ◽  
Fuels Treatment ◽  
Fuel Layer ◽  
Long Duration ◽  
Western Us ◽  
Residual Tree

Mechanical mastication is a fuels treatment that shreds midstorey trees and shrubs into a compacted woody fuel layer to abate fire hazards in fire-prone ecosystems. Increased surface fuel loading from mastication may, however, lead to undesirable fire intensity, long-duration flaming or smouldering, and undesirable residual tree mortality. Two major questions facing fuels managers are: how long do masticated fuels persist, and how does the composition of masticated fuelbeds change over time? To evaluate these changes, we measured 25 masticated sites with a range of vegetation, species masticated and time since treatment (1–16 years) in the western US. Seven of the 25 sites were sampled nearly a decade earlier, providing a unique opportunity to document fuelbed changes. Woody fuel loading ranged from 12.1 to 91.9Mg ha−1 across sites and was negatively related to time since treatment. At remeasured sites, woody fuel loads declined by 20%, with the greatest losses in 1- and 10-h woody fuels (69 and 33% reductions in mass respectively). Reductions were due to declines in number of particles and reduced specific gravity. Mastication treatments that generate greater proportions of smaller-diameter fuels may result in faster decomposition and potentially be more effective at mitigating fire hazard.

scholarly journals Fire Hazard in Chattogram City Corporation Area: A Critical Analysis of Its Causes and Mitigation Measures

2021 ◽  
Vol 3 ◽  
Author(s):  
Muhammad Rashidul Hasan ◽  
Md. Rakibul Hasan Kauser ◽  
Jihan Ibrahim
Keyword(s):  
Geographical Information Systems ◽  
Fire Hazard ◽  
Geographical Information ◽  
Mitigation Measures ◽  
Primary Data ◽  
Fire Intensity ◽  
Short Period ◽  
Fire Stations ◽  
Fire Accidents ◽  
Over Time

Fire can have its origin either in natural or human activities resulting in death and/or property damage in a very short period of time. To develop fire hazard-resilient cities proper attention should be given to all possible sections of development to facilitate the service. Chattogram City is the second largest city of Bangladesh. Due to rapid rate of urbanization and unplanned growth of urban centers; hazards like fire have become a menace for the Chattogram City Corporation (CCC) area. So, the main objective of this research is to identify the nature of the fire hazard by analyzing frequency and intensity over time through different checklists and analyzing the existing firefighting capacity. In addition to past fire incident records, a direct questionnaire survey was utilized and expert opinion was solicited for primary data collection. Using geographical information systems (GIS) techniques, this study found that nine fire stations in the CCC area exhibited different frequency and intensity in different categories such as type of structure, land use, source of fire, damage, and losses in last 5 years. The number of fire incidents increased from 200 to 675 which indicates that the frequency increased over time. Among 2,514 fire accidents, 47% occurred in residential areas and 27% occurred in commercial areas. Fire intensity also varied with seasonal variation over a year. Within the last 5 years, the Chattogram City Corporation dealt with a 179,091,200 BDT financial loss and 83 people were injured, of which 15 were due to fire accidents. One the other hand, only nine fire stations serve the ~155 sq.km area and ~6 million people live in the CCC area which is 17 and 19 times larger than that of Bangkok and Oklahoma City. Finally, this data-driven approach and findings could help emergency planners to take necessary steps for improving firefighting capability to ensure better fire safety and resiliency.

Corrigendum to: The effect of woody fuel characteristics on fuel ignition and consumption: a case study from a eucalypt forest in south-west Western Australia

2019 ◽  
Vol 28 (8) ◽  
pp. 640
Author(s):  
J. J. Hollis ◽  
W. L. McCaw ◽  
M. G. Cruz
Keyword(s):  
Fuel Consumption ◽  
Fire History ◽  
Management Practices ◽  
Woody Debris ◽  
Fuel Load ◽  
Fire Behaviour ◽  
Ecological Processes ◽  
Eucalypt Forest ◽  
Eucalypt Forests ◽  
Fuel Particles

Coarse woody debris (&gt;0.6cm in diameter) is an important component of the fuel complex in Australian eucalypt forests, influencing both fire behaviour, smoke production and post-fire ecological processes. We investigated how physical characteristics of woody fuel affected ignition and consumption during an experimental fire where the fuel complex characteristics, fire weather and fire behaviour varied within a narrow range. Decay status, bark condition, arrangement, suspension and extent of charring were classified for 2866 coarse woody fuel particles. We used generalised linear model (GLM) analysis to explain ignition success and the extent of consumption of individual particles, with a focus on larger diameter fuels (&gt;7.5cm in diameter), which comprised 83% of the woody fuel load and 94% of the woody fuel consumed during the flaming and smouldering stages of combustion. Ignition success was best explained by a model that included fuel arrangement (a surrogate of fuel proximity), suspension and decay status. The extent of fuel consumption was greater for pieces in advanced stages of decay, but suspension (inversely related) and arrangement (directly related) also affected the outcome. Forest management practices, previous fire history and other natural disturbances are likely to influence the distribution of pre-fire diameters and suspension classes that characterise large woody fuels at a site, and will therefore influence woody fuel consumption. This has practical implications for quantifying heat release and atmospheric emissions from fires burning in forests with different management histories.

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