Quantifying the effect of fuel reduction treatments on fire behavior in boreal forests

2013 ◽  
Vol 43 (1) ◽  
pp. 97-102 ◽  
Author(s):  
B.W. Butler ◽  
R.D. Ottmar ◽  
T.S. Rupp ◽  
R. Jandt ◽  
E. Miller ◽  
...  
Keyword(s):  
Energy Release ◽  
Boreal Forests ◽  
Fire Hazard ◽  
Control Treatment ◽  
Maximum Temperature ◽  
Fire Intensity ◽  
Prescribed Burn ◽  
Fuel Treatments ◽  
Cumulative Energy ◽  
Maximum Heat

Mechanical (e.g., shearblading) and manual (e.g., thinning) fuel treatments have become the preferred strategy of many fire managers and agencies for reducing fire hazard in boreal forests. This study attempts to characterize the effectiveness of four fuel treatments through direct measurement of fire intensity and forest floor consumption during a single prescribed burn. The treatments included (1) thinning trees and removing debris (THIN-REMOVE-1 and -2), (2) thinning trees and burning the debris onsite, (3) shearblading and leaving the debris in place (SHEAR), and (4) shearblading and piling the debris in windrows (SHEAR-ROW). Fire burned through treatments 1, 3, and 4 and one control unit. The highest fire intensities (maximum temperature of 1150 °C, maximum heat flux of 227 kW·m–2, and fire cumulative energy release of 4277 J·m–2) were measured in the control. Treatment 1 exhibited a peak temperature of 267 °C, peak heating of 16 kW·m–2, and cumulative energy release of 2600 J·m–2. Treatments 3 and 4 exhibited peak temperatures of 170 and 66 °C, peak heating of 51 and 3 kW·m–2, and cumulative energy release of 2500 and 1800 J·m–2, respectively. The thinned treatment showed the most significant impact in the context of reduced heat release.

The effect of leaf beetle herbivory on the fire behaviour of tamarisk (Tamarix ramosissima Lebed.)

2013 ◽  
Vol 22 (4) ◽  
pp. 446 ◽  
Author(s):  
Gail M. Drus ◽  
Tom L. Dudley ◽  
Matt L. Brooks ◽  
J. R. Matchett
Keyword(s):  
Great Basin ◽  
Fire Hazard ◽  
Leaf Beetle ◽  
Flame Length ◽  
Maximum Temperature ◽  
Fire Intensity ◽  
Native Vegetation ◽  
Vegetation Density ◽  
Fire Behaviour ◽  
Litter Depth

The non-native tree, Tamarix spp. has invaded desert riparian ecosystems in the south-western United States. Fire hazard has increased, as typically fire-resistant native vegetation is replaced by Tamarix. The tamarisk leaf beetle, Diorhabda carinulata Desbrochers, introduced for biological control, may affect fire behaviour by converting hydrated live Tamarix leaves and twigs into desiccated and dead fuels. This potentially increases fire hazard in the short term before native vegetation can be re-established. This study investigates how fire behaviour is altered in Tamarix fuels desiccated by Diorhabda herbivory at a Great Basin site, and by herbivory simulated by foliar herbicide at a Mojave Desert site. It also evaluates the influence of litter depth on fire intensity. Fire behaviour was measured with a fire intensity index that integrates temperature and duration (degree-minutes above 70°C), and with maximum temperature, duration, flame lengths, rates of spread and vegetation removal. Maximum temperature, flame length and rate of spread were enhanced by foliar desiccation of Tamarix at both sites. At only the Mojave site, there was a trend for desiccated trees to burn with greater fire intensity. At both sites, fire behaviour parameters were influenced to a greater degree by litter depth, vegetation density and drier and windier conditions than by foliar desiccation.

scholarly journals Prescribed burning in a mediterranean-climate region mitigates the disturbance by bushfire to a critical food resource for an endangered bird, the Carnaby’s cockatoo

Fire Ecology ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Valerie S. Densmore ◽  
Emma S. Clingan
Keyword(s):  
Seed Production ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Fire Hazard ◽  
Food Resource ◽  
Management Tool ◽  
Fire Intensity ◽  
Prescribed Burns ◽  
Low Intensity ◽  
Percentage Survival

Abstract Background Prescribed burning is used to reduce fire hazard in highly flammable vegetation types, including Banksia L.f. woodland that occurs on the Swan Coastal Plain (SCP), Western Australia, Australia. The 2016 census recorded well over 1.9 million people living on the SCP, which also encompasses Perth, the fourth largest city in Australia. Banksia woodland is prone to frequent ignitions that can cause extensive bushfires that consume canopy-stored banksia seeds, a critical food resource for an endangered bird, the Carnaby’s cockatoo (Calyptorynchus latirostris, Carnaby 1948). The time needed for banksias to reach maturity and maximum seed production is several years longer than the typical interval between prescribed burns. We compared prescribed burns to bushfires and unburned sites at three locations in banksia woodland to determine whether low-intensity prescribed burns affect the number of adult banksias and their seed production. Study sites were matched to the same vegetation complex, fire regime, and time-since-fire to isolate fire intensity as a variable. Results Headfire rates of spread and differenced normalized burn ratios indicated that prescribed burning was generally of a much lower intensity than bushfire. The percentage survival of adult banksias and their production of cones and follicles (seeds) did not decrease during the first three years following a prescribed burn. However, survival and seed production were significantly diminished followed high-intensity bushfire. Thus, carrying capacity for Carnaby’s cockatoo was unchanged by prescribed burning but decreased markedly following bushfire in banksia woodland. Conclusions These results suggest that prescribed burning is markedly different from bushfire when considering appropriate fire intervals to conserve canopy habitats in fire-resilient vegetation communities. Therefore, low-intensity prescribed burning represents a viable management tool to reduce the frequency and extent of bushfire impacts on banksia woodland and Carnaby’s cockatoo.

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.

Mobile X-Pol Radar: A New Tool for Investigating Pyroconvection and Associated Wildfire Meteorology

2018 ◽  
Vol 99 (6) ◽  
pp. 1177-1195 ◽  
Author(s):  
Nicholas McCarthy ◽  
Hamish McGowan ◽  
Adrien Guyot ◽  
Andrew Dowdy
Keyword(s):  
Multispectral Imaging ◽  
Doppler Radar ◽  
Fire Behavior ◽  
Time Lapse ◽  
Fire Intensity ◽  
Prescribed Burn ◽  
X Band ◽  
Turbulent Characteristics ◽  
Convective Plume ◽  
Dual Polarized

AbstractThe process of pyroconvection occurs when fire-released heat, moisture, and/or aerosols induce or augment convection in the atmosphere. Prediction of pyroconvection presents a set of complex problems for meteorologists and wildfire managers. In particular, the turbulent characteristics of a pyroconvective plume exert bidirectional feedback on fire behavior, often with resulting severe impacts on life and property. Here, we present the motivation, field strategy, and initial results from the Bushfire Convective Plume Experiment, which through the use of mobile radar aims to quantify the kinematics of pyroconvection and its role in fire behavior. The case studies presented include world-first observations from two wildfires and one prescribed burn using the University of Queensland’s portable, dual-polarized X-band Doppler radar (UQ-XPOL). The initial analyses of reflectivity, Doppler winds, polarimetric variables, and spectrum width data provide insights into these relatively unexplored datasets within the context of pyroconvection. Weather radar data are supported by mesonet observations, time-lapse photography, airborne multispectral imaging, and spot-fire mapping. The ability to combine ground-validated fire intensity and progression at an hourly scale with quantitative data documenting the evolution of the convective plume kinematics at the scale of hundreds of meters represents a new capability for advancing our understanding of wildfires. The results demonstrate the suitability of portable, dual-polarized X-band Doppler radar to investigate pyroconvection and associated plume dynamics.

scholarly journals The Assessment of the Maximum Heat Production and Cooling Effectiveness of Three Different Drill Types (Conical vs. Cylindrical vs. Horizontal) during Implant Bed Preparation—An In Vitro Study

2021 ◽  
Vol 11 (21) ◽  
pp. 9961
Author(s):  
Stefan Ihde ◽  
Bartosz Dalewski ◽  
Łukasz Pałka
Keyword(s):  
In Vitro Study ◽  
Maximum Temperature ◽  
Internal Cooling ◽  
Type I ◽  
Ir Camera ◽  
Maximum Heat ◽  
Disc Cutters ◽  
Cooling Hole ◽  
Implant Bed

The aim of this experimental study was to verify thermal diffusion differences, by measuring the maximum temperature achieved with different drill shapes. Synthetic bone blocks of type I density made from solid rigid polyurethane (PUR) foam were used to perform the drilling procedures. The experiment was conducted at three different rotation speeds: 800, 3000 and 5000 rpm. Conical drills (with and without an internal cooling hole) were compared with horizontal drills and disc drills. The temperature during drilling for implant bed preparation was estimated with the use of thermocouples and an infrared (IR) camera. The temperature during drilling with disc cutters for lateral basal implants did not exceed 33 ∘C and the temperature decreased in proportion to higher drill speed. The results indicate that the tested design is safe and will not cause bone overheating.

scholarly journals Flame Temperatures Saturate with Increasing Dead Material in Ulex europaeus, but Flame Duration, Fuel Consumption and Overall Flammability Continue to Increase

Fire ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 6 ◽  
Author(s):  
Jennifer Dent ◽  
Hannah Buckley ◽  
Audrey Lustig ◽  
Timothy Curran
Keyword(s):  
Linear Relationship ◽  
Fire Hazard ◽  
Maximum Temperature ◽  
Ulex Europaeus ◽  
Plant Trait ◽  
Non Linear ◽  
Dead Material ◽  
Components Analysis ◽  
Fuel Accumulation ◽  
The Relationship

A key determinant of wildfire behaviour is the flammability of constituent plants. One plant trait that influences flammability is the retention of dead biomass, as the low moisture content of dead material means less energy is required to achieve combustion. However, the effect of the dead-to-live ratio of fuel on plant flammability has rarely been experimentally quantified. Here we examine the nature of the relationship between dead fuel accumulation and flammability in Ulex europaeus (common gorse). Shoots with varying proportions of dead material were ignited in a purpose-built plant-burner. Three components of flammability were measured: sustainability (flame duration), consumability (proportion burnt biomass) and combustibility (maximum temperature). While flame duration and proportion burnt biomass had a positive linear relationship with the proportion of dead material, the response of maximum temperature was positive but non-linear. All three flammability components were reduced to a single variable using principal components analysis; this had a non-linear relationship with the proportion of dead material. The response of maximum temperature to dead material plateaued at 39%. These findings have implications for the management of habitats invaded by gorse; to mitigate fire hazard associated with gorse, stands should be kept at a relatively young age when dead fuel is less prevalent.

Experimental and Simulation Studies of Thermal Distribution on Modified Connector of Li-Ion Battery for Electric Vehicles Application

2016 ◽  
Vol 6 (5) ◽  
pp. 2064
Author(s):  
Agus Risdiyanto ◽  
Umar Khayam ◽  
Noviadi A. Rachman ◽  
Maulana Arifin
Keyword(s):  
Contact Resistance ◽  
Contact Area ◽  
Fire Hazard ◽  
Lithium Ion ◽  
Maximum Temperature ◽  
Silver Coating ◽  
Li Ion Battery ◽  
Steady State Condition ◽  
Li Ion ◽  
Dc Current

<p>One of the several failure cases in electric vehicle could be occured at the Lithium-ion (Li-ion) battery connectors when loaded by high current. This failure caused by bad contact of connectors so that the contact resistance increase and lead to high power losses, overheating, and it can even cause a fire hazard. This paper presents a thermal distributions of  Li-ion battery connectors on different coating material in relation to the value of contact resistance. There were two test samples of modeled: copper connection without coating and copper connection with silver coating. Each sample was loaded by the DC current of 350A, and temperature at the connection was measured until steady state condition reached and simulated by Solidwork software. The results show that the temperature at the inside contact area was higher than the outside contact area of connection that appears caused by higher of the contact resistance. Both measurement and simulation results have same tendency that copper connection with silver coating having lower contact resistance, lower maximum temperature, and lower losses about 32 % than copper connection without  coating. Silver coating can be considered as other alternative to prevent overheating, high losses, and failure in Li-ion battery connector.</p>

An optimization model for locating fuel treatments across a landscape to reduce expected fire losses

2008 ◽  
Vol 38 (4) ◽  
pp. 868-877 ◽  
Author(s):  
Yu Wei ◽  
Douglas Rideout ◽  
Andy Kirsch
Keyword(s):  
Spatial Information ◽  
Solution Process ◽  
Fire Risk ◽  
Simulation Models ◽  
Mixed Integer ◽  
Fire Intensity ◽  
Fuel Treatments ◽  
Fuel Treatment ◽  
Mip Model ◽  
Fire Ignition

Locating fuel treatments with scarce resources is an important consideration in landscape-level fuel management. This paper developed a mixed integer programming (MIP) model for allocating fuel treatments across a landscape based on spatial information for fire ignition risk, conditional probabilities of fire spread between raster cells, fire intensity levels, and values at risk. The fire ignition risk in each raster cell is defined as the probability of fire burning a cell because of the ignition within that cell. The conditional probability that fire would spread between adjacent cells A and B is defined as the probability of a fire spreading into cell B after burning in cell A. This model locates fuel treatments by using a fire risk distribution map calculated through fire simulation models. Fire risk is assumed to accumulate across a landscape following major wind directions and the MIP model locates fuel treatments to efficiently break this pattern of fire risk accumulation. Fuel treatment resources are scarce and such scarcity is introduced through a budget constraint. A test case is designed based on a portion of the landscape (15 552 ha) within the Southern Sierra fire planning unit to demonstrate the data requirements, solution process, and model results. Fuel treatment schedules, based upon single and dual wind directions, are compared.

Simulating fuel treatment effects in dry forests of the western United States: testing the principles of a fire-safe forest

2011 ◽  
Vol 41 (5) ◽  
pp. 1018-1030 ◽  
Author(s):  
Morris C. Johnson ◽  
Maureen C. Kennedy ◽  
David L. Peterson
Keyword(s):  
United States ◽  
Treatment Effects ◽  
Fire Hazard ◽  
Fire Behavior ◽  
Post Treatment ◽  
Western United States ◽  
Crown Fire ◽  
Fuel Treatments ◽  
Dry Forests ◽  
Fuel Treatment

We used the Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS) to simulate fuel treatment effects on 45 162 stands in low- to midelevation dry forests (e.g., ponderosa pine ( Pinus ponderosa Dougl. ex. P. & C. Laws.) and Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) of the western United States. We evaluated treatment effects on predicted post-treatment fire behavior (fire type) and fire hazard (torching index). FFE-FVS predicts that thinning and surface fuel treatments reduced crown fire behavior relative to no treatment; a large proportion of stands were predicted to transition from active crown fire pre-treatment to surface fire post-treatment. Intense thinning treatments (125 and 250 residual trees·ha–1) were predicted to be more effective than light thinning treatments (500 and 750 residual trees·ha–1). Prescribed fire was predicted to be the most effective surface fuel treatment, whereas FFE-FVS predicted no difference between no surface fuel treatment and extraction of fuels. This inability to discriminate the effects of certain fuel treatments illuminates the consequence of a documented limitation in how FFE-FVS incorporates fuel models and we suggest improvements. The concurrence of results from modeling and empirical studies provides quantitative support for “fire-safe” principles of forest fuel reduction (sensu Agee and Skinner 2005. For. Ecol. Manag. 211: 83–96).

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