Effects of salvage logging and pile-and-burn on fuel loading, potential fire behaviour, fuel consumption and emissions

2013 ◽  
Vol 22 (6) ◽  
pp. 757 ◽  
Author(s):  
Morris C. Johnson ◽  
Jessica E. Halofsky ◽  
David L. Peterson
Keyword(s):  
Fuel Consumption ◽  
Field Measurements ◽  
Flame Length ◽  
Pollutant Emissions ◽  
Fire Behaviour ◽  
Treatment Combination ◽  
Fuel Loading ◽  
Fuel Treatment ◽  
Salvage Logging ◽  
Study Results

We used a combination of field measurements and simulation modelling to quantify the effects of salvage logging, and a combination of salvage logging and pile-and-burn fuel surface fuel treatment (treatment combination), on fuel loadings, fire behaviour, fuel consumption and pollutant emissions at three points in time: post-windstorm (before salvage logging), post-salvage logging and post-surface fuel treatment (pile-and-burn). Salvage logging and the treatment combination significantly reduced fuel loadings, fuelbed depth and smoke emissions. Salvage logging and the treatment combination reduced total surface fuel loading (sound plus rotten) by 73 and 77%. All fine woody fuels (<7.6cm) were significantly reduced by salvage logging and the treatment combination. In contrast, there was significant increase in the 1000-h (7.6–22.9cm) fuel loading. Salvage logging and the treatment combination reduced mean fuelbed depth by 38 and 65%. Salvage logging reduced PM2.5 emissions by 19%, and the treatment combination reduced emissions by 27%. Salvage logging and the treatment combination reduced PM10 emissions by 19 and 28%. We observed monotonic changes in flame length, reaction intensity and rate-of-spread after salvage logging and treatment combination. Study results illustrate potential differences between the effects of salvage logging after windstorms and the effects of salvage logging after wildfire.

Fire behaviour in masticated forest fuels: lab and prescribed fire experiments

2018 ◽  
Vol 27 (4) ◽  
pp. 280 ◽  
Author(s):  
Zachary D. Lyon ◽  
Penelope Morgan ◽  
Camille S. Stevens-Rumann ◽  
Aaron M. Sparks ◽  
Robert F. Keefe ◽  
...  
Keyword(s):  
Pinus Ponderosa ◽  
Prescribed Fire ◽  
Laboratory Experiments ◽  
Prescribed Burning ◽  
Cost Effective ◽  
Flame Length ◽  
Fire Behaviour ◽  
Fuel Loading ◽  
Forest Fuels ◽  
Fire Experiments

Managers masticate fuels to reduce extreme fire hazards, but the effect on fire behaviour within the resulting compact fuelbeds is poorly understood. We burned 54 masticated fuelbeds in laboratory experiments one and two growing seasons after mastication and 75 masticated fuelbeds in prescribed fire experiments one growing season after treatment in three replicate Pinus ponderosa stands. Mastication treatments reduced density of trees >5 cm diameter by 30–72% resulting in total fuel depth of 6.9–13.7 cm and surface woody fuel loading of 1.0–16.0 kg m−2. Flame length and rate of spread were low and similar for coarse and fine mastication treatments and controls. Smouldering combustion lasted 6–22 h in prescribed fire experiments where fuelbeds included duff and were well mixed by machinery, compared with <2 h in the laboratory where fuelbeds did not include duff and had varying fuel moisture. Fuel consumption in the prescribed fires was highly variable, ranging from 0 to 20 cm in depth and was less from 2-year-old fuelbeds than 1-year-old fuelbeds in laboratory burns. Compared with fine mastication treatments, coarse treatments took less time to implement and were more cost-effective. Although laboratory experiments expand our understanding of burning masticated fuels under controlled conditions, they did not readily translate to prescribed burning conditions where fuels, weather and ignition patterns were more variable. This highlights the need for more laboratory experiments and in situ research that together can be used to develop much-needed, scalable predictive models of mastication combustion.

scholarly journals Examining fuel treatment longevity through experimental and simulated surface fire behaviour: a maritime pine case study

2009 ◽  
Vol 39 (12) ◽  
pp. 2529-2535 ◽  
Author(s):  
Paulo M. Fernandes
Keyword(s):  
Treatment Effectiveness ◽  
Residual Effect ◽  
Fire Spread ◽  
Flame Length ◽  
Maritime Pine ◽  
Fire Behaviour ◽  
Fuel Treatment ◽  
Surface Fire ◽  
Fire Modelling ◽  
The Difference

The adequate prediction of fire behaviour characteristics for both scientific and management objectives is deeply impacted by the performance of fire behaviour models. Both the lack of experimentation and limitations in fire modelling constrain current understanding of fuel treatment effectiveness and longevity. The residual effect of a 10-year-old prescribed fire was quantified by both simulating fire behaviour and observing real-world fire behaviour in treated (T10) and untreated (U25) fuels in a 25-year-old maritime pine ( Pinus pinaster Aiton) stand in Portugal. Fire behaviour characteristics were measured in experimental surface fires (n = 36). Surface-fire behaviour was simulated using BehavePlus with custom fuel models for T10, U25, and U15 (the untreated fuel complex when the stand was 15 years old). The T10 fuel complex had significantly less decomposing litter load and shrub cover and load than the U25 fuel complex. The observed rate of fire spread did not differ between fuel complexes after accounting for the effects of other environmental variables, but flame length in T10 was 25% lower than that in U25. BehavePlus simulations contradicted the difference observed in flame length. Inconsistent and misleading assessments of fuel treatment effectiveness with detrimental impacts on the outcomes of fuel management may result from the generalized practice of solely using simulation in lieu of experimental fires.

scholarly journals Factors Affecting the Rate of Fuel Consumption in Aircrafts

2021 ◽  
Vol 13 (14) ◽  
pp. 8066
Author(s):  
Thowayeb H. Hassan ◽  
Abu Elnasr E. Sobaih ◽  
Amany E. Salem
Keyword(s):  
Fuel Consumption ◽  
Positive Association ◽  
Pollutant Emissions ◽  
Aviation Industry ◽  
Factors Affecting ◽  
Fuel Flow ◽  
Homogeneity Of Variance ◽  
Strong Positive Association ◽  
Ground Distance ◽  
The Cost

The cost of fuel and its availability are among the most major concerns for aircrafts and the aviation industry overall. Environmental difficulties with chemical pollutant emissions emitted by aviation machines are also connected to fuel consumption. As a result, it is crucial to examine factors that affect the overall fuel usage and consumption in the airport-based aviation industry. Several variables were investigated related to the total fuel consumed, such as dry operating weight (DOW) (KG), zero-fuel weight (ZFW), take-off weight (TOW), air distance (AIR DIST) (KM), and ground distance (GDN DIST). Analysis of the correlation between total fuel consumed as well as the extra fuel and selected variables was conducted. The results showed that the most positively associated factors with the total used fuel were the air distance (r2 = 0.86, p < 0.01), ground distance (r2 = 0.78, p < 0.01), TOW (r2 = 0.68, p < 0.01), and flight time (r2 = 0.68, p < 0.01). There was also a strong positive association between the average fuel flow (FF) and actual TOW (r2 = 0.74, p < 0.01) as well as ZFW (r2 = 0.61, p < 0.01). The generalized linear model (GLM) was utilized to assess the predictions of total energy usage after evaluating important outliers, stability of the homogeneity of variance, and the normalization of the parameter estimation. The results of multiple linear regression revealed that the most significant predictors of the total consumed fuel were the actual ZFW (p < 0.01), actual TOW (p < 0.01), and actual average FF (p < 0.05). The results interestingly confirmed that wind speed has some consequences and effects on arrival fuel usage. The result reflects that thermal and hydrodynamic economies impact on the flying fuel economy. The research has various implications for both scholars and practitioners of aviation industry.

scholarly journals Soil Erosion Estimates in Arid Region: A Case Study of the Koutine Catchment, Southeastern Tunisia

2021 ◽  
Vol 11 (15) ◽  
pp. 6763
Author(s):  
Mongi Ben Zaied ◽  
Seifeddine Jomaa ◽  
Mohamed Ouessar
Keyword(s):  
Soil Erosion ◽  
Soil Loss ◽  
Scientific Evidence ◽  
Field Measurements ◽  
Spatiotemporal Variability ◽  
Soil Conditions ◽  
Storm Events ◽  
Erosion Processes ◽  
Study Results ◽  
Soil Losses

Soil erosion remains one of the principal environmental problems in arid regions. This study aims to assess and quantify the variability of soil erosion in the Koutine catchment using the RUSLE (Revised Universal Soil Loss Equation) model. The Koutine catchment is located in an arid area in southeastern Tunisia and is characterized by an annual mean precipitation of less than 200 mm. The model was used to examine the influence of topography, extreme rainstorm intensity and soil texture on soil loss. The data used for model validation were obtained from field measurements by monitoring deposited sediment in settlement basins of 25 cisterns (a traditional water harvesting and storage technique) over 4 years, from 2015 to 2018. Results showed that slope is the most controlling factor of soil loss. The average annual soil loss in monitoring sites varies between 0.01 and 12.5 t/ha/y. The storm events inducing the largest soil losses occurred in the upstream part of the Koutine catchment with a maximum value of 7.3 t/ha per event. Soil erosion is highly affected by initial and preceding soil conditions. The RUSLE model reasonably reproduced (R2 = 0.81) the spatiotemporal variability of measured soil losses in the study catchment during the observation period. This study revealed the importance of using the cisterns in the data-scarce dry areas as a substitute for the classic soil erosion monitoring fields. Besides, combining modeling of outputs and field measurements could improve our physical understanding of soil erosion processes and their controlling factors in an arid catchment. The study results are beneficial for decision-makers to evaluate the existing soil conservation and water management plans, which can be further adjusted using appropriate soil erosion mitigation options based on scientific evidence.

A Multidisciplinary Approach for the Comprehensive Assessment of Integrated Rotorcraft–Powerplant Systems at Mission Level

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Ioannis Goulos ◽  
Fakhre Ali ◽  
Konstantinos Tzanidakis ◽  
Vassilios Pachidis ◽  
Roberto d'Ippolito
Keyword(s):  
Environmental Impact ◽  
Fuel Consumption ◽  
Comprehensive Assessment ◽  
Pollutant Emissions ◽  
Operational Performance ◽  
Civil Aviation ◽  
Accurate Estimation ◽  
Nox Emissions ◽  
Reactor Model ◽  
Stirred Reactor

This paper presents an integrated methodology for the comprehensive assessment of combined rotorcraft–powerplant systems at mission level. Analytical evaluation of existing and conceptual designs is carried out in terms of operational performance and environmental impact. The proposed approach comprises a wide-range of individual modeling theories applicable to rotorcraft flight dynamics and gas turbine engine performance. A novel, physics-based, stirred reactor model is employed for the rapid estimation of nitrogen oxides (NOx) emissions. The individual mathematical models are implemented within an elaborate numerical procedure, solving for total mission fuel consumption and associated pollutant emissions. The combined approach is applied to the comprehensive analysis of a reference twin-engine light (TEL) aircraft modeled after the Eurocopter Bo 105 helicopter, operating on representative mission scenarios. Extensive comparisons with flight test data are carried out and presented in terms of main rotor trim control angles and power requirements, along with general flight performance charts including payload-range diagrams. Predictions of total mission fuel consumption and NOx emissions are compared with estimated values provided by the Swiss Federal Office of Civil Aviation (FOCA). Good agreement is exhibited between predictions made with the physics-based stirred reactor model and experimentally measured values of NOx emission indices. The obtained results suggest that the production rates of NOx pollutant emissions are predominantly influenced by the behavior of total air inlet pressure upstream of the combustion chamber, which is affected by the employed operational procedures and the time-dependent all-up mass (AUM) of the aircraft. It is demonstrated that accurate estimation of on-board fuel supplies ahead of flight is key to improving fuel economy as well as reducing environmental impact. The proposed methodology essentially constitutes an enabling technology for the comprehensive assessment of existing and conceptual rotorcraft–powerplant systems, in terms of operational performance and environmental impact.

Numerical and Experimental Study on the Impact of Mild Cold EGR on Exhaust Emissions in a Biodiesel Fueled Diesel Engine

2021 ◽  
Author(s):  
Alex Oliveira ◽  
Junfeng Yang ◽  
Jose Sodre
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Exhaust Emissions ◽  
Pollutant Emissions ◽  
Cylinder Pressure ◽  
Nox Formation ◽  
Ratio Distribution ◽  
Engine Model ◽  
Gas Recirculation ◽  
The Impact

Abstract This work evaluated the effect of cooled exhaust gas recirculation (EGR) on fuel consumption and pollutant emissions from a diesel engine fueled with B8 (a blend of biodiesel and Diesel 8:92%% by volume), experimentally and numerically. Experiments were carried out on a Diesel power generator with varying loads from 5 kW to 35 kW and 10% of cold EGR ratio. Exhaust emissions (e.g. THC, NOX, CO etc.) were measured and evaluated. The results showed mild EGR and low biodiesel content have minor impact of engine specific fuel consumption, fuel conversion efficiency and in-cylinder pressure. Meanwhile, the combination of EGR and biodiesel reduced THC and NOX up to 52% and 59%, which shows promising effect on overcoming the PM-NOX trade-off from diesel engine. A 3D CFD engine model incorporated with detailed biodiesel combustion kinetics and NOx formation kinetics was validated against measured in-cylinder pressure, temperature and engine-out NO emission from diesel engine. This valid model was then employed to investigate the in-cylinder temperature and equivalence ratio distribution that predominate NOx formation. The results showed that the reduction of NOx emission by EGR and biodiesel is obtained by a little reduction of the local in-cylinder temperature and, mainly, by creating comparatively rich combusting mixture.

scholarly journals Biomass burning fuel consumption dynamics in the tropics and subtropics assessed from satellite

2016 ◽  
Vol 13 (12) ◽  
pp. 3717-3734 ◽  
Author(s):  
Niels Andela ◽  
Guido R. van der Werf ◽  
Johannes W. Kaiser ◽  
Thijs T. van Leeuwen ◽  
Martin J. Wooster ◽  
...  
Keyword(s):  
South America ◽  
Fuel Consumption ◽  
Spatial Patterns ◽  
Field Measurements ◽  
Sub Saharan Africa ◽  
Burned Area ◽  
Return Periods ◽  
Sub Saharan ◽  
In Fire ◽  
Consumption Dynamics

Abstract. Landscape fires occur on a large scale in (sub)tropical savannas and grasslands, affecting ecosystem dynamics, regional air quality and concentrations of atmospheric trace gasses. Fuel consumption per unit of area burned is an important but poorly constrained parameter in fire emission modelling. We combined satellite-derived burned area with fire radiative power (FRP) data to derive fuel consumption estimates for land cover types with low tree cover in South America, Sub-Saharan Africa, and Australia. We developed a new approach to estimate fuel consumption, based on FRP data from the polar-orbiting Moderate Resolution Imaging Spectroradiometer (MODIS) and the geostationary Spinning Enhanced Visible and Infrared Imager (SEVIRI) in combination with MODIS burned-area estimates. The fuel consumption estimates based on the geostationary and polar-orbiting instruments showed good agreement in terms of spatial patterns. We used field measurements of fuel consumption to constrain our results, but the large variation in fuel consumption in both space and time complicated this comparison and absolute fuel consumption estimates remained more uncertain. Spatial patterns in fuel consumption could be partly explained by vegetation productivity and fire return periods. In South America, most fires occurred in savannas with relatively long fire return periods, resulting in comparatively high fuel consumption as opposed to the more frequently burning savannas in Sub-Saharan Africa. Strikingly, we found the infrequently burning interior of Australia to have higher fuel consumption than the more productive but frequently burning savannas in northern Australia. Vegetation type also played an important role in explaining the distribution of fuel consumption, by affecting both fuel build-up rates and fire return periods. Hummock grasslands, which were responsible for a large share of Australian biomass burning, showed larger fuel build-up rates than equally productive grasslands in Africa, although this effect might have been partially driven by the presence of grazers in Africa or differences in landscape management. Finally, land management in the form of deforestation and agriculture also considerably affected fuel consumption regionally. We conclude that combining FRP and burned-area estimates, calibrated against field measurements, is a promising approach in deriving quantitative estimates of fuel consumption. Satellite-derived fuel consumption estimates may both challenge our current understanding of spatiotemporal fuel consumption dynamics and serve as reference datasets to improve biogeochemical modelling approaches. Future field studies especially designed to validate satellite-based products, or airborne remote sensing, may further improve confidence in the absolute fuel consumption estimates which are quickly becoming the weakest link in fire emission estimates.

The wildland - urban interface fire problem - current approaches and research needs

2010 ◽  
Vol 19 (2) ◽  
pp. 238 ◽  
Author(s):  
William E. Mell ◽  
Samuel L. Manzello ◽  
Alexander Maranghides ◽  
David Butry ◽  
Ronald G. Rehm
Keyword(s):  
Wildland Fire ◽  
Fire Suppression ◽  
Economic Cost ◽  
Field Measurements ◽  
The United States ◽  
Test Methods ◽  
Wildland Urban Interface ◽  
Fuel Treatment ◽  
Treatment Techniques ◽  
Exposure Conditions

Wildfires that spread into wildland–urban interface (WUI) communities present significant challenges on several fronts. In the United States, the WUI accounts for a significant portion of wildland fire suppression and wildland fuel treatment costs. Methods to reduce structure losses are focussed on fuel treatments in either wildland fuels or residential fuels. There is a need for a well-characterised, systematic testing of these approaches across a range of community and structure types and fire conditions. Laboratory experiments, field measurements and fire behaviour models can be used to better determine the exposure conditions faced by communities and structures. The outcome of such an effort would be proven fuel treatment techniques for wildland and residential fuels, risk assessment strategies, economic cost analysis models, and test methods with representative exposure conditions for fire-resistant building designs and materials.

Sign in / Sign up

Export Citation Format

Share Document