Elliptical-fire perimeter- and area-intensity distributions

1992 ◽  
Vol 22 (7) ◽  
pp. 968-972 ◽  
Author(s):  
E. A. Catchpole ◽  
M. E. Alexander ◽  
A. M. Gill
Keyword(s):  
Potential Application ◽  
Shape Factor ◽  
Fire Management ◽  
Fire Intensity ◽  
Spatial Distributions ◽  
Spread Rate ◽  
Ignition Point ◽  
Area Burned ◽  
Elliptical Shape

Equations are presented for determining the proportion of the total perimeter and area burned for a simple elliptically shaped fire for any specified range of Byram's fireline intensities. The same principles apply to any characteristic that is dependent on fireline intensity. Only three inputs are required: head-fire intensity; the elliptical shape factor; and the backfire spread rate. This last quantity is not required if it is assumed that the ignition point is at one focus of the ellipse. The spatial distributions produced have potential application to fire management.

Land Zoning Based on Fire History

1997 ◽  
Vol 7 (3) ◽  
pp. 249 ◽  
Author(s):  
G Bovio ◽  
A Camia
Keyword(s):  
Fire History ◽  
Fire Management ◽  
Fire Frequency ◽  
Basic Unit ◽  
Spread Rate ◽  
Analysis Techniques ◽  
Area Burned ◽  
Management Plans ◽  
Fire Planning

An approach to land zoning for fire planning purposes through classification of geographical units referred to as Basic Units - in a multivariate context is proposed. The method, developed for large areas, employs a few statistics computed from historical fire data, that were selected with the aim of depicting a ''fire history profile'' of each Basic Unit. The statistics were chosen in order to describe different aspects, such as fire frequency, fire continuity, average and maximum area burned and average area spread rate of fires. Using the computed statistics as variables, the Basic Units can be aggregated with cluster analysis techniques and classes can be defined, each class of Basic Units representing a land zone with a specific mean fire history profile. Fire management decisions can be tailored according to the properties of clusters. The method was successfully applied for supporting fire management plans in two Regions of Northern Italy, where the Basic Units were chosen with an administrative criterion.

Microplot Sampling of Fire Behavior on Populus tremuloides Stands in North-Central Colorado

1993 ◽  
Vol 3 (2) ◽  
pp. 85 ◽  
Author(s):  
JK Smith ◽  
RD Laven ◽  
PN Omi
Keyword(s):  
Populus Tremuloides ◽  
Fire Behavior ◽  
Fire Effects ◽  
Flame Length ◽  
Fire Intensity ◽  
Total Heat Release ◽  
Spread Rate ◽  
North Central ◽  
Area Burned ◽  
In Fire

Fire behavior research has traditionally used whole burns as sampling units. Numerous burns were required to quantify relationships between pre-burn descriptors, fire behavior, and fire effects. Recent studies have used small plots within burns (called microplots) as the sampling units. This study measured pre-burn descriptors and fire behavior on 0.75-m2 microplots in two Populus tremuloides Michx. burns in north-central Colorado. Microplot estimates of woody fuels, spread rate, and area burned were comparable with measurements from whole burns. Two methods of estimating fire intensity on microplots produced inconsistent results. Juniperus communis L. patches burned more intensely and released more heat than herbaceous areas. Duff characteristics were the most useful pre-burn descriptors for predicting area burned, spread rate, flame length, and total heat release. Microplot sampling on two bums enabled us to relate variability in fire behavior to pre-burn characteristics and to obtain replicate estimates of these relationships.

scholarly journals Multiproxy Holocene Fire Records From the Tropical Savannas of Northern Cape York Peninsula, Queensland, Australia

2021 ◽  
Vol 9 ◽  
Author(s):  
Emma Rehn ◽  
Cassandra Rowe ◽  
Sean Ulm ◽  
Patricia Gadd ◽  
Atun Zawadzki ◽  
...  
Keyword(s):  
Fire Management ◽  
Fire Regimes ◽  
Fire Intensity ◽  
Methodological Innovation ◽  
Management Planning ◽  
Indigenous Management ◽  
Northern Cape ◽  
Cape York

Paleoecology has demonstrated potential to inform current and future land management by providing long-term baselines for fire regimes, over thousands of years covering past periods of lower/higher rainfall and temperatures. To extend this potential, more work is required for methodological innovation able to generate nuanced, relevant and clearly interpretable results. This paper presents records from Cape York Peninsula, Queensland, Australia, as a case study where fire management is an important but socially complex modern management issue, and where palaeofire records are limited. Two new multiproxy palaeofire records are presented from Sanamere Lagoon (8,150–6,600 cal BP) and Big Willum Swamp (3,900 cal BP to present). These records combine existing methods to investigate fire occurrence, vegetation types, and relative fire intensity. Results presented here demonstrate a diversity of fire histories at different sites across Cape York Peninsula, highlighting the need for finer scale palaeofire research. Future fire management planning on Cape York Peninsula must take into account the thousands of years of active Indigenous management and this understanding can be further informed by paleoecological research.

scholarly journals Estimating Suppression Expenditures for Individual Large Wildland Fires

2007 ◽  
Vol 22 (3) ◽  
pp. 188-196 ◽  
Author(s):  
Krista M. Gebert ◽  
David E. Calkin ◽  
Jonathan Yoder
Keyword(s):  
Wildland Fire ◽  
Fire Suppression ◽  
The United States ◽  
Primary Objective ◽  
Fiscal Year ◽  
Fire Intensity ◽  
Intensity Level ◽  
Policy Debate ◽  
Wildland Fires ◽  
Area Burned

Abstract The extreme cost of fighting wildland fires has brought fire suppression expenditures to the forefront of budgetary and policy debate in the United States. Inasmuch as large fires are responsible for the bulk of fire suppression expenditures, understanding fire characteristics that influence expenditures is important for both strategic fire planning and onsite fire management decisions. These characteristics then can be used to produce estimates of suppression expenditures for large wildland fires for use in wildland fire decision support or after-fire reviews. The primary objective of this research was to develop regression models that could be used to estimate expenditures on large wildland fires based on area burned, variables representing the fire environment, values at risk, resource availability, detection time, and National Forest System region. Variables having the largest influence on cost included fire intensity level, area burned, and total housing value within 20 mi of ignition. These equations were then used to predict suppression expenditures on a set of fiscal year 2005 Forest Service fires for the purpose of detecting “extreme” cost fires—those fires falling more than 1 or 2 SDs above or below their expected value.

Empirical modelling of surface fire behaviour in maritime pine stands

2009 ◽  
Vol 18 (6) ◽  
pp. 698 ◽  
Author(s):  
Paulo M. Fernandes ◽  
Hermínio S. Botelho ◽  
Francisco C. Rego ◽  
Carlos Loureiro
Keyword(s):  
Wind Speed ◽  
Moisture Content ◽  
Fire Spread ◽  
Fire Intensity ◽  
Fuel Moisture ◽  
Fire Behaviour ◽  
Spread Rate ◽  
Surface Fire ◽  
Rate Of Spread ◽  
Fuel Moisture Content

An experimental burning program took place in maritime pine (Pinus pinaster Ait.) stands in Portugal to increase the understanding of surface fire behaviour under mild weather. The spread rate and flame geometry of the forward and backward sections of a line-ignited fire front were measured in 94 plots 10–15 m wide. Measured head fire rate of spread, flame length and Byram’s fire intensity varied respectively in the intervals of 0.3–13.9 m min–1, 0.1–4.2 m and 30–3527 kW m–1. Fire behaviour was modelled through an empirical approach. Rate of forward fire spread was described as a function of surface wind speed, terrain slope, moisture content of fine dead surface fuel, and fuel height, while back fire spread rate was correlated with fuel moisture content and cover of understorey vegetation. Flame dimensions were related to Byram’s fire intensity but relationships with rate of spread and fine dead surface fuel load and moisture are preferred, particularly for the head fire. The equations are expected to be more reliable when wind speed and slope are less than 8 km h–1 and 15°, and when fuel moisture content is higher than 12%. The results offer a quantitative basis for prescribed fire management.

Multidecadal trends in area burned with high severity in the Selway-Bitterroot Wilderness Area 1880–2012

2017 ◽  
Vol 26 (11) ◽  
pp. 930 ◽  
Author(s):  
Penelope Morgan ◽  
Andrew T. Hudak ◽  
Ashley Wells ◽  
Sean A. Parks ◽  
L. Scott Baggett ◽  
...  
Keyword(s):  
Fire Management ◽  
Early Period ◽  
Burn Severity ◽  
Area Burned ◽  
High Severity ◽  
Wilderness Area ◽  
Severity Class ◽  
Recent Trends ◽  
Term Data

Multidecadal trends in areas burned with high severity shape ecological effects of fires, but most assessments are limited to ~30 years of satellite data. We analysed the proportion of area burned with high severity, the annual area burned with high severity, the probability areas burned with high severity and also the area reburned (all severities and high burn severity only) over 133 years across 346265ha within the Selway-Bitterroot Wilderness (SBW) Area in Idaho, United States. We used burn severity class inferred from digitised aerial photography (1880–2000) and satellite imagery (1973–2012). Over this long record, the proportion burned with high severity did not increase, despite extensive area burned in recent decades. Much greater area burned with high severity during the Early (1880–1934) and Late (1975–2012) periods than during the Middle period (1935–1974), paralleling trends in area burned. Little area reburned with high severity, and fires in the Early period limited the extent of fires burning decades later in the Late period. Our results suggest that long-term data across large areas provides useful context on recent trends, and that projections for the extent and severity of future fires must consider prior fires and fire management.

scholarly journals An assessment of the implementation and outcomes of recent changes to fire management in the Kruger National Park

Koedoe ◽  
2008 ◽  
Vol 50 (1) ◽  
Author(s):  
Brian W. Van Wilgen ◽  
Navashni Govender ◽  
Sandra MacFadyen
Keyword(s):  
National Park ◽  
Fire Management ◽  
Fire Regime ◽  
Kruger National Park ◽  
Fire Intensity ◽  
Target Area ◽  
Large Fires ◽  
Sufficient Degree ◽  
Burnt Areas ◽  
In Fire

This paper reviews recent changes in fire management in the Kruger National Park, and assesses the resulting fire patterns against thresholds of potential concern. In 2002, a lightning-driven approach was replaced by an approach that combined point ignitions with unplanned and lightning fires. The approach aimed to burn an annual target area, determined by rainfall and fuel conditions, in point-ignition fires of different sizes. Most of the original fire-related thresholds of potential concern (TPCs) were incorporated into the new approach. The annual target area to be burnt ranged from 12 to 24% of the park between 2002 and 2006. The total area burnt generally exceeded the targets each year, and management fires accounted for less than half of the total area burnt. The fire regime was dominated by very large fires (> 5 000 ha) which accounted for 77% of the total area burnt. New TPCs were developed to assess whether the fire regime encompassed a sufficient degree of variability, in terms of fire intensity and the spatial distribution of burnt areas. After assessment and adjustment, it appears that these TPCs have not yet been exceeded. The point-ignition approach, and its evaluation in terms of variability and heterogeneity, is based on the untested assumption that a diverse fire regime will promote biodiversity. This assumption needs to be critically assessed. We recommend that the practice of point ignitions be continued, but that greater efforts be made to burn larger areas earlier in the season to reduce large and intense dry-season fires.

Productivity of Ontario initial-attack fire crews: results of an expert-judgement elicitation study

2004 ◽  
Vol 34 (3) ◽  
pp. 705-715 ◽  
Author(s):  
Kelvin G Hirsch ◽  
Justin J Podur ◽  
Robert F Janser ◽  
Robert S McAlpine ◽  
David L Martell
Keyword(s):  
Fire Management ◽  
Fire Suppression ◽  
Probability Distributions ◽  
Management Program ◽  
Expert Judgement ◽  
Fire Intensity ◽  
Initial Attack ◽  
Time Estimates ◽  
Elicitation Study ◽  
Distribution Parameters

A structured expert-judgement elicitation technique was used to develop probability distributions for fireline production rates for Ontario's three- and four-person initial-attack crews for seven common fuel types and two distinct levels of fire intensity (i.e., low, 500 kW/m; moderate, 1500 kW/m). A total of 141 crew leaders provided 900 estimates of the minimum, maximum, and most likely (mode) time to construct 610 m (2000 ft) of fireline. This information was used to estimate parameters for beta probability distributions for each individual and scenario. Analysis of variance (ANOVA) of the beta-distribution parameters (α and β) and the three time estimates indicated that fuel type, intensity, crew size, and crew-leader experience all have a statistically significant (p < 0.05) influence on estimated crew productivity. The 28 scenario-specific and 7 aggregated distributions and expected values can be used in many operational fire-management activities (e.g., presuppression planning, initial-attack dispatching, initial-fire assessments) and incorporated into initial-attack containment models. These results also provide baseline data on crew productivity that can be used in larger strategic analyses to gauge the benefits of new fire-suppression equipment and techniques for the entire fire-management program.

Stress intensity factors for part-elliptical cracks emanating from dimpled rivet holes

2014 ◽  
Vol 03 (04) ◽  
pp. 1450022
Author(s):  
Ailun Wang ◽  
Chongmin She ◽  
Gang Lin ◽  
You Zhou ◽  
Wanlin Guo
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Empirical Formula ◽  
Shape Factor ◽  
Engineering Application ◽  
Least Square ◽  
Intensity Factors ◽  
Elliptical Shape ◽  
Corner Cracks

Detailed investigations on the stress intensity factors (SIFs) for corner cracks emanated from interference fitted dimpled rivet holes are conducted using three-dimensional finite element method. The influences of the crack length a, elliptical shape factor t, far-end stress S and interference magnitude δ on the stress intensity factors are systematically studied. The SIFs for corner cracks emanated from open holes are also investigated for comparisons. An empirical formula of the normalized SIF is proposed by use of the least square method for convenience of the engineering application, which is a function of the crack length a, elliptical shape factor t, far-end stress S, interference magnitude δ and the normalized elliptical centrifugal angle φn. Based on the empirical formula, a crack growth simulation for a rivet filled hole is conducted, which shows a good agreement with the test data.

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