Flammability descriptors of fine dead fuels resulting from two mechanical treatments in shrubland: a comparative laboratory study

2010 ◽  
Vol 19 (3) ◽  
pp. 314 ◽  
Author(s):  
Eva Marino ◽  
Javier Madrigal ◽  
Mercedes Guijarro ◽  
Carmen Hernando ◽  
Carmen Díez ◽  
...  
Keyword(s):  
Logistic Models ◽  
Ignition Source ◽  
Fuel Load ◽  
Experimental Conditions ◽  
Load Effect ◽  
Consumption Ratio ◽  
Wildfire Hazard ◽  
Western Spain ◽  
Shrub Clearing ◽  
Fuel Moisture Content

Mechanical treatments are traditionally used to modify the fuel complex in shrubland, but information about their actual effectiveness in reducing the risk of wildfire initiation is scarce. The effects of two mechanical fuel treatments (shrub clearing with crushing and manual removal) on flammability in a shrubland community in north-western Spain were compared. Three months after treatment, laboratory tests using a point-ignition source were conducted on the fine dead fuels to analyse the effect of type of treatment and fuel moisture content (FMC) under two conditions: (1) flaming; or (2) glowing+wind ignition source. Fuel load effect within each treatment was also studied. Time-to-ignition, flaming duration, number of burnt sides of the sample and fuel consumption ratio were assessed. Logistic models were developed to assess ignition and sustained combustion probabilities. Type of treatment and FMC significantly affected flammability under both experimental conditions tested. Slow smouldering was observed in fuels subjected to shrub clearing and removal, whereas crushing fuels were rapidly burnt with flaming phase combustion. In general, shrub clearing and removal appeared to be more effective in reducing wildfire hazard in these shrubland communities.

Combustion and Nutrient Losses During Laboratory Burns

1995 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
D Gillon ◽  
V Gomendy ◽  
C Houssard ◽  
J Marechal ◽  
JC Valette
Keyword(s):  
Moisture Content ◽  
Fuel Consumption ◽  
Fire Spread ◽  
Fuel Load ◽  
Maximum Temperature ◽  
Fuel Moisture ◽  
Nutrient Losses ◽  
Constant Moisture Content ◽  
Fuel Moisture Content ◽  
Experimental Burns

The aim of this study was to assess the effects on combustion characteristics, and their consequences on nutrient losses, of (1) the change in load and packing ratio of the fuel bed, and (2) the change in fuel moisture content. Eighty-one experimental burns were carried out, on a test bench in the laboratory; the fuel was composed of needles and twigs of Pinus pinaster. Two levels of fuel load an dpacking ratio (8t ha-1 needles, packing ratio of 0.040; and 16t ha-1 twigs and needles, packing ratio of 0.066) were compared at constant moisture content (6%); and four levels of moisture content(6%, 12%, 24% and 30% dry weight) were compared at constant fuel load (8t ha-1 needles). At constant moisture content, an increase in the load and packing ratio of the fuel bed led to an increase in the height of flames and in the maximum temperature 25 cm above the fuel bed, in the duration of the rise in temperatures within the fuel, and in the fireline intensity. Conversely, the rate of fire spread decreased. At constant fuel load, an increase in the moisture content of the fuel led to a decrease in the rate of fire spread, in the flame height and the maximum temperature 25 cm above the fuel bed, and in the fireline intensity. In contrast, the maximum temperatures reached within the fuel, when the flaming front was continuous, did not significantly change with varying fuel loads or fuel moisture contents. The percentage fuel consumption was always high, more than 80%, but it significantly decreased with increasing fuel load and packing ratio and with increasing moisture content. Total losses of N, S, and K significantly decreased with increasing fuel load and packing ratio, with increasing moisture content and with decreasing percentage fuel consumption. Losses in P only significantly decreased with increasing fuel load and packing ratio. Losses in Mg and Ca were not significantly affected by fuel load, moisture content. or percentage consumption. An attempt was made to separate volatile from particulate losses, based on the assumption that all the losses of Ca were in particulate form. Whereas losses in particulate form remained relatively constant, losses of nutrients in volatile form seem to have been related to the percentage fuel consumption. Even if these experimental burns were of low intensity (40 to 56 kW m-1), their impact, in terms of lethal temperatures and nutrient losses, was not negligible, particularly for N and P. The increasing fireline intensity with increasing fuel load was not accompanied by an enhancement in the proportion of nutrient losses. In the same way, the strong decrease in fireline intensity with increasing fuel moisture content led only to a slight decrease in some nutrient losses. It was through their effect on the percentage fuel consumption that fuel load or moisture content modified the nutrient losses, particularly volatile losses.

Prediction for Burned Area of Forest Fires Based on SVM Model

2014 ◽  
Vol 513-517 ◽  
pp. 4084-4089 ◽  
Author(s):  
Dao Wen Xie ◽  
Shi Liang Shi
Keyword(s):  
Forest Fires ◽  
Fuel Load ◽  
Burned Area ◽  
Support Vector ◽  
Machine Model ◽  
Guangzhou City ◽  
Svm Model ◽  
Forest Fuel ◽  
Using Data ◽  
Fuel Moisture Content

Forest fire spreading is a complex burning phenomenon, and it is difficult to build a general spreading model for the fires occurred in different area over the world, even in the same country. Accordingly, predicting the burned area of forest fires is also a challenging task. In this work, five attributes (i.e. forest fuel moisture content, forest fuel inflammability, forest fuel load ,slope and burning time) are selected as input to predict burned area of forest fires occurred in the area of Guangzhou City in China. Next, using Data Mining (DM) technique, an SVM (Support Vector Machine) model was built and applied to deal with this type of a regression task, predicting burned area. Results showed that the selection of input attributes was reasonable, and the proposed SVM model was suitable for prediction of burned area, with higher precision, better generalization. This work provided a new way to deal with predictions for burned area of forest fires.

Models for predicting fire ignition probability in graminoids from boreo–temperate moorland ecosystems

2016 ◽  
Vol 25 (6) ◽  
pp. 679 ◽  
Author(s):  
Victor M. Santana ◽  
Rob H. Marrs
Keyword(s):  
Late Summer ◽  
Early Spring ◽  
Fuel Load ◽  
Probability Models ◽  
Rating Systems ◽  
Seasonal Differences ◽  
Ignition Probability ◽  
Critical Moisture ◽  
Fuel Moisture Content ◽  
Fire Ignition

An increase in both the frequency and severity of wildfires in boreo–temperate ecosystems is predicted. Therefore, to develop efficient fire rating systems, the relationship between the fuel moisture content (FMC) of vegetation and ignition thresholds needs to be determined. We developed fire ignition probability models for three graminoid species collected in central England, but common in boreo–temperate ecosystems (Eriophorum angustifolium, E. vaginatum and Molinia caerulea). Specifically, we assessed through laboratory experiments (1) seasonal differences between early spring and late summer in fuel traits such as height, fuel load, fuel bulk density and dead fuel load proportion, and (2) the role of these fuel traits, environmental conditions and dead FMC in determining the probability of ignition. There were seasonal differences in fuel traits among species, with an increase in dead fuel load proportion after winter. The dead FMC was the only variable determining initial sustained ignitions. However, the seasonal differences in dead fuel were not sufficient to affect the FMC threshold at which graminoids start to ignite. Graminoids begin to ignite at high levels of dead FMC, and there are differences between species (from 36.1% to 48.1%). This work assists in improving fire ignition predictions in graminoid-dominated ecosystems by providing warnings based on critical moisture thresholds.

Fuel management effectiveness in a mixed heathland: a comparison of the effect of different treatment types on fire initiation risk

2012 ◽  
Vol 21 (8) ◽  
pp. 969 ◽  
Author(s):  
Eva Marino ◽  
Carmen Hernando ◽  
Javier Madrigal ◽  
Carmen Díez ◽  
Mercedes Guijarro
Keyword(s):  
Moisture Content ◽  
Prescribed Burning ◽  
Structural Characteristics ◽  
Logistic Models ◽  
Minor Effect ◽  
Fuel Moisture ◽  
Fuel Management ◽  
Treatment Type ◽  
Fire Initiation ◽  
Fuel Moisture Content

Fuel management is commonly used to reduce fire risk in fire-prone shrubland, but information about the real efficacy of the different techniques is scarce. In this study, we assessed in the laboratory the effects of different treatment types on fire initiation risk in a mixed heathland. The effects of two mechanical treatments and of prescribed burning were compared with untreated vegetation. Flammability tests were performed in samples of the regenerated shrubs and fine ground fuels present 2 years after treatments. Results indicate that all treatments were effective in reducing fire initiation risk in regenerated shrubs, but not in fine ground fuels. Recovery of vegetation differed between treatments, and treatment type had a significant effect on flammability, mainly affecting fire sustainability. Wind speed had a minor effect on shrub fuel flammability, whereas fuel moisture had a significant effect. The flammability of fine ground fuels differed significantly depending on fuel moisture content, even at the low levels tested. Logistic models were fitted to predict successful fire sustainability, and the probability of initial propagation was obtained as a function of treatment type, fuel moisture content and fuel structural characteristics. This study provides new insights into wildfire prevention in shrubland, and compares the effectiveness of different fuel treatment techniques.

Laboratory determination of factors influencing successful point ignition in the litter layer of shrubland vegetation

2008 ◽  
Vol 17 (5) ◽  
pp. 628 ◽  
Author(s):  
Matt P. Plucinski ◽  
Wendy R. Anderson
Keyword(s):  
Logistic Function ◽  
Major Effect ◽  
Ignition Source ◽  
Litter Type ◽  
Litter Layer ◽  
Standard Type ◽  
Ignition Point ◽  
Factors Affecting ◽  
Fuel Moisture Content ◽  
Fire Spreading

Factors affecting ignition thresholds of the litter layer of shrubland vegetation were investigated using reconstructed litter beds in a laboratory. The factors investigated were fuel moisture content (FMC), litter type (primarily species), pilot ignition source, and wind. Litter beds made from 11 different litter types were ignited with point ignition sources. Litter from Allocasuarina nana (Sieber ex Spreng.) L.A.S. Johnson was used as the standard type across all experiments. Successful ignition was defined as fire spreading a fixed distance from the ignition point. Ignition success was modelled as a logistic function of FMC. Litter type had a major effect on ignitibility. The bulk density of the litter bed and the surface area of litter per volume of litter bed provided reasonably good predictors of the effect of litter type on ignition success. Low-density litter beds ignited at higher FMCs than dense litter beds. The two densest litter beds failed to ignite with the procedures used here. The ignition sources tested had significantly different effects on ignition success. Larger ignition sources were able to ignite wetter fuels than smaller sources. The presence of wind was found to have a different effect on ignition success depending on the location of the ignition source with respect to the litter bed. Wind decreased ignition success when the ignition source was located on top of the litter bed, but aided ignition when the ignition source was located within the litter bed.

scholarly journals Combustion behavior of rotary solid porous burners (RSPB)

2020 ◽  
Vol 187 ◽  
pp. 03012
Author(s):  
Niwat Ketchat ◽  
Bundit Krittacom
Keyword(s):  
Porous Media ◽  
Combustion Efficiency ◽  
Wire Mesh ◽  
Fuel Load ◽  
Exhaust Gas ◽  
Input Rate ◽  
Air Flow Rate ◽  
Experimental Conditions ◽  
Complete Combustion ◽  
Combustion Behavior

The combustion behavior of rotary solid porous burners (RSPB), i.e., temperature (T), exhaust gas (CO and NOx) and combustion efficiency (nc) were investigated. The stainless wire-mesh type of porous media was selected as porous absorber with porosity of 0.82, thickness of 4.2 mm. The rice husk was used as the fuel with the humidity around 12-14%. The experiment showed that the T tends to increase following the rotating velocity (ro) rising around 0.5-1 rpm. When a ro increased to 1.5 rpm, a T had tendency decreasingly. Because, a ro was too high resulting in the fuel in combustion chamber were ejected quickly then the reaction time reduced not enough to burn fuel, leading to incomplete combustion. The air flow rate (Qa) of 40 m3/h and the fuel load input rate (Qf) of 2.3 kg/h, gave the highest of T due to the system become complete combustion. Corresponding to the level of CO, the least level was obtained at ro = 1 rpm, Qf = 2.3 kg/h and Qa = 40 m3/h. The qc yielded highest with 93.7% at the same condition. The NOx in this research was considered as low, not more than 40 ppm in all experimental conditions.

scholarly journals Silviculture can facilitate repeat prescribed burn programs with long-term strategies

2022 ◽  
pp. 104-111
Author(s):  
Robert A. York ◽  
Jacob Levine ◽  
Daniel Foster ◽  
Scott Stephens ◽  
Brandon Collins
Keyword(s):  
Fuel Consumption ◽  
Prescribed Fire ◽  
Fire Suppression ◽  
Relative Proportion ◽  
Canopy Cover ◽  
Basal Area ◽  
Fuel Load ◽  
Prescribed Burn ◽  
Wildfire Hazard ◽  
Initial Entry

A significant expansion of prescribed fire activity will be necessary to mitigate growing wildfire hazard in California forests. Forest managers can facilitate this expansion by promoting forest structures that allow for more effective implementation of prescribed fire, for both initial-entry and repeat burns. We analyzed changes in surface fuel during a series of three burns in replicated mixed-conifer stands following a period of over 100 years of fire suppression and exclusion. Total fuel load, proportion of pine present, canopy cover and basal area of live trees were relevant forest-structure components that influenced plot-scale fuel consumption. The study highlighted the importance of pre-fire fuel load and the relative proportion of pine in the overstory, which both led to greater amounts of fuel consumption. The initial-entry burn dramatically reduced all fuel categories (fine fuel, coarse wood and duff). Following each burn, fuel recovered until the next burn reduced loads enough to maintain low fuel levels. We apply the results to provide an example of how to determine the timing of prescribed fires.

Got to burn to learn: the effect of fuel load on grassland fire behaviour and its management implications

2018 ◽  
Vol 27 (11) ◽  
pp. 727 ◽  
Author(s):  
Miguel G. Cruz ◽  
Andrew L. Sullivan ◽  
James S. Gould ◽  
Richard J. Hurley ◽  
Matt P. Plucinski
Keyword(s):  
Fire Spread ◽  
Flame Height ◽  
Fuel Load ◽  
Limiting Factor ◽  
Fire Behaviour ◽  
Load Effect ◽  
Fire Propagation ◽  
Rate Of Spread ◽  
Eastern Australia ◽  
Modelling Assumptions

The effect of grass fuel load on fire behaviour and fire danger has been a contentious issue for some time in Australia. Existing operational models have placed different emphases on the effect of fuel load on model outputs, which has created uncertainty in the operational assessment of fire potential and has led to end-user and public distrust of model outcomes. A field-based experimental burning program was conducted to quantify the effect of fuel load on headfire rate of spread and other fire behaviour characteristics in grasslands. A total of 58 experimental fires conducted at six sites across eastern Australia were analysed. We found an inverse relationship between fuel load and the rate of spread in grasslands, which is contrary to current, untested, modelling assumptions. This result is valid for grasslands where fuel load is not a limiting factor for fire propagation. We discuss the reasons for this effect and model it to produce a fuel load effect function that can be applied to operational grassfire spread models used in Australia. We also analyse the effect of fuel load on flame characteristics and develop a model for flame height as a function of rate of fire spread and fuel load.

Effects of fuel load and moisture content on fire behaviour and heating in masticated litter-dominated fuels

2013 ◽  
Vol 22 (4) ◽  
pp. 440 ◽  
Author(s):  
Jesse K. Kreye ◽  
Leda N. Kobziar ◽  
Wayne C. Zipperer
Keyword(s):  
Moisture Content ◽  
Fuel Load ◽  
Maximum Temperature ◽  
Fire Behaviour ◽  
Fuel Loading ◽  
Pine Flatwoods ◽  
Rate Of Spread ◽  
Soil Temperatures ◽  
Fuel Moisture Content ◽  
In Fire

Mechanical fuels treatments are being used in fire-prone ecosystems where fuel loading poses a hazard, yet little research elucidating subsequent fire behaviour exists, especially in litter-dominated fuelbeds. To address this deficiency, we burned constructed fuelbeds from masticated sites in pine flatwoods forests in northern Florida with palmetto-dominated understoreys and examined the effects of fuel load and fuel moisture content (FMC) on fire behaviour. Flame lengths (49–140 cm) and fireline intensity (183–773 kJ m–1 s–1) increased with loading (10–30 Mg ha–1) and were reduced by 40 and 47% with increasing FMC from 9 to 13%. Rate of spread was not influenced by fuel load, but doubled under drier FMC. Fuel consumption was >90% for all burns. Soil temperatures were influenced by both fuel load and FMC, but never reached lethal temperatures (60°C). However, temperatures of thermocouple probes placed at the fuelbed surface reached 274–503°C. Probe maximum temperature and duration at temperatures ≥60°C (9.5–20.0°C min) both increased with fuel load, but were unaffected by FMC. The fire behaviour observed in these unique litter-dominated fuelbeds provides additional insight into the burning characteristics of masticated fuels in general.

scholarly journals Análise do conteúdo de umidade foliar de fitofisionomias do Cerrado com uso de imagens do multispectral instrument do satélite Sentinel 2

2020 ◽  
Vol 13 (07) ◽  
pp. 3315
Author(s):  
Leidiane De Paula Rezende ◽  
Ricardo Vicente Ferreira
Keyword(s):  
Moisture Content ◽  
Dry Weight ◽  
Short Wave ◽  
Fuel Load ◽  
Fuel Moisture ◽  
Reflectance Analysis ◽  
Short Wave Infrared ◽  
Atmospheric Variations ◽  
Fuel Moisture Content ◽  
Sentinel 2

O estudo realizou uma análise comparativa entre o índice de reflectância de duas fitofisionomias (Macega e Cerradão) do Cerrado nas bandas de imagens do Instrumento Multiespectral (MSI) do satélite Sentinel 2 das bandas Short-wave infrared (SWIR) 1 e 2 e Near Infra-Red (NIR) de duas fitofisionomias do Cerrado em consonância com os dados in situ de Fuel Moisture Content (FMC) afim de contribuir com técnicas de Sensoriamento Remoto para monitorar combustíveis vegetais e perigos de incêndio. Dados adicionais de variáveis ambientais como temperatura e umidade do ar, e de satélites como precipitação e conteúdo de umidade de solo foram consideradas neste estudo. A análise dos dados foi feita com a aplicação de correlação linear e de regressão múltipla. No FMC, os resultados ficaram acima de 100% para o Cerradão e para a Macega atingiu valor mínimo de 20%. Na análise de correlação, a banda NIR se correlacionou positivamente (R² = 0,32) ao FMC do Cerradão, enquanto na Macega, a melhor correlação foi identificada nas bandas do SWIRs (R² = 0,36) inversamente ao FMC. Na análise de regressão, o FMC do Cerradão indicou correspondência à umidade de solo. Conclui-se que vegetais vivos tendem a recorrer a umidade do solo, enquanto que os vegetais mortos são mais afetados por variáveis atmosféricas e, por isso, são mais propensos a incêndios, como a Macega. O monitoramento do FMC por Sensoriamento Remoto requer maior amostragem em relação ao bioma Cerrado, cuja fisiologia complexa mostra ser influenciada por variáveis ambientais e climáticas que deverão ser levadas em conta em análises e estudos posteriores.  Leaf moisture content analysis of Cerrado phytophysiognomies using Sentinel 2 satellite multispectral instrument images   A B S T R A C T Moisture content of living or dead plant material is a fundamental element in the characterization of the fire's fuel load in wildfire episodes. Satellite imagery and field surveys can help to estimate Fuel Moisture Content (FMC) in different environments. FMC is computed as wet weight over dry weight of vegetation samples. In this study, 24 FMC samples of Brazilian Savana vegetation were collected between May and October 2019 in two phytotypes: Cerrado Típico and Campo Limpo, in the municipality of Sacramento / MG. We applied an statistic correlation to reflectance of the Sentinel-2 MSI spectral bands (Multispectral Instrument). Data on soil moisture, temperature, precipitation and air humidity were tested in a Multiple Linear Regression to verify possible impacts of these elements on FMC results. SWIR 1 band had a better correlation (R² = 0.33) with Campo Limpo samples, the reflectance increases as the plant's humidity decreases, turning to dead leaves. In Cerrado Típico, FMC increased during the period, keeping leaves alive. Dead leaves are affected by atmospheric variations and are more prone to burning. The risk of fire is imminent in Campo Limpo and reflectance analysis of short wave infrared (SWIR) is a strategy to predict risk of fires in this environment.Keywords:  wildfire risk; fuel moisture content; reflectance

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