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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Insurance And Risk Related Equine Study In Eastern Halifax Regional Halifax Municipality

Green, Nathalie 01 August 2012 (has links)
On June 13, 2008 a forest fire affected Eastern Halifax Regional Municipality leading to the evacuation of five hundred homes and eighteen horse facilities. At the time of the June 2008 forest fire not all horses in Nova Scotia were insured. I am using the horse facilities affected by the fire as a natural experiment to answer the following question: Did the June 2008 forest fire cause horse facility operators to change their insurance decisions? To answer this question surveys were completed by horse facilities in the affected (treatment) and unaffected (control) areas. Data collected from horse facilities operators suggest they did change insurance decisions. Given the proximity in time and place to the June 2008 forest fire, horse facilities in both the treatment and control groups felt more at risk and were likely motivated to insure coverage for a low probability but high risk hazard.
22

Brandrelaterade insekters lokala artrikedom i förhållande till olika miljövariabler : Fokus på betydelsen av konnektivitet på brandfält i boreal skog i Västerbottens län

Pettersson, Julia January 2015 (has links)
The last century, forest fires have decreased in frequency due to efficient fire-suppression along with the growth of the industrial forestry. Since 1990, fire has been reintroduced under controlled forms to recreate burnt habitats. Many species that are dependent on, or benefits from, forest fires have increased since fire was reintroduced. The importance of connectivity is often addressed in ecological research. This is particularly important for species dependent on short-lived habitats such as burnt forests. The aim of this study was to investigate if a higher connectivity between burnt forests leads to an increased occurrence of fire-related insects. The study also attempts to determine in what way connectivity and other variables in a burnt forest, such as amount of living and dead wood, distance to the coast and altitude, affects fire-related species. To investigate this, six burnt forests in Västerbotten County were sampled for fire-related insects. The sites were chosen along a gradient from high to low connectivity and close to far from the coast. The results showed that there are too few burnt forests in Västerbotten County to conduct a study of this magnitude. Still, the results provide an insight in how different environmental variables affect the number of fire-related species. The results showed a trend that increasing amount of living and dead wood and longer distance from the coast increase the local richness of fire-related species. Concerning the main aim in the study about connectivity, the analysis gives no support to either accept or reject the hypothesis.
23

An investigation of the impacts of massive short distance spotting on the forward rate of spread of forest fires

Macaulay, Andrew S. Unknown Date (has links) (PDF)
Massive short distance spotting has been suspected of increasing the forward rate of spread of bushfires since McArthur (1967) attributed a three-fold increase in rate of spread to short distance spotting at a fire in Daylesford. However, research into spotting has generally focussed on the prediction of long distance spotting, perhaps because of its more obvious effects on suppression of bushfires. The amount of spotting that a fire generates and the distance that spotfires start from the main fire is dependent on the amount and type of bark fuel present, as this is the primary source of embers. / Existing models of fire behaviour have proposed only one model that allows spotting to influence the forward rate of spread of the main fire - the formation of pseudo fire fronts. This thesis proposes two new inl1uence mechanisms; pre-frontal burnout and the "indraught effect". Three hypotheses have been formed to test these three influence mechanisms. / As it is difficult, costly and dangerous to use high intensity fires for experimental purposes, a fire simulation model (SAROS) was developed to run on a personal computer. The SAROS model is based on the McArthur fire behaviour model (1967), with the addition of mechanisms that allow spotting to affect the forward rate of spread of the main fire. SAROS has been tested against data from fires where spotting was thought to have significantly increased the forward rate of spread, and is shown to be a reasonable model of fire behaviour. / Further experiments were carried out to test the sensitivity of the model to the input variables and the impact of each of the variables in the model on changes in forward rate of spread due to spotting. The SAROS model shows that it is possible for massive short distance spotting to increase the forward rate of spread by over 300% of the McArthur predicted rate of spread. However under the conditions where McArthur reported spotting increasing the rate of spread by a factor of three, the SAROS model accounts fbI' only around two thirds of that increase.
24

A stochastic spatial model for the consumption of organic forest soils in a smoldering ground fire /

Holt, Benjamin Victor. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 72-74). Also available via Humboldt Digital Scholar.
25

Space-time analysis of forest fires /

Díaz Avalos, Carlos, January 1998 (has links)
Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (110-119).
26

Činnost orgánů samosprávy a návrh metodického postupu při řešení rozsáhlého lesního požáru. / Function of local government authorities and suggestion for methodical plan to adress the extensive forest fire.

KLEČATSKÁ, Lucie January 2012 (has links)
As the title suggests, this diploma thesis is focused on the activities of self-governing bodies in the event of extensive forest fires. First, the theoretical part describes general information about forest fires that concerns, among other things, the most common causes and kinds of forest fires. Drawing on this part, there is information on various ways of extinguishing fires, especially by means of the aerial fire-fighting service. The chapter of The Present State is further focused on legislation and the tasks of self-governing bodies in the event of extensive forest fires because the competences and duties of mayors have to be clearly defined in such serious situations, which consequently enhances the clarity of the situation. This diploma thesis follows two objectives. The first one is the evaluation of the activities of self-governing bodies in the event of extensive forest fires, and in connection with this, pointing out possible flaws. For this, a hypothesis has been established claiming that it is necessary to increase the readiness quality of the self-governing bodies for the possible occurrence of extensive forest fires. The other objective is to prepare a methodical process draft for solving an extensive forest fire. The output of the thesis is a methodical draft or manual, which should support the preparation for and solution of such situations. This final thesis will provided as a study material for students. The methodical draft will be further offered to mayors of municipalities that are endangered by forest fires.
27

Zoneamento de Risco de Incêndios Florestais na Reserva Biológica do Aguaí / Forest fire risk zoning at Aguai Biological Reserve

Liz, João Paulo Czarnecki de 24 March 2014 (has links)
Made available in DSpace on 2016-12-12T20:12:28Z (GMT). No. of bitstreams: 1 PGEF14MA011.pdf: 2057019 bytes, checksum: 230c76c381dec0b6aa736817205d3552 (MD5) Previous issue date: 2014-03-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The forest fire risk zoning (ZRIF) is a very important tool for the prevention, monitoring, planning, fire and definition of public policies regarding the maintenance of the ecological heritage. Fires risky to the environment, in addition according to their proportion it can be very difficult to control and combat. Then thinking in terms of monitoring and prevention arises need to develop methodologies to perform ZRIF of native forest reserves in the state of Santa Catarina, which is the main focus of this research. The study was conducted at Aguaí Biological Reserve which is located in the foothills of the Serra Geral in the southern state, with an elevation between 200 and 1400 meters and area of 7,672 ha. The study areas were divided into REBIO of Aguaí with 7,874 ha and the surrounding area with 18,441 ha. The study areas are home to the sources from which the rivers that supply the southern Santa Catarina region, directly affecting 450,000 people. The research sought to validate and improve techniques for ZRIF already applied by authors such as Oliveira (2000 ) , Koproski (2010 ), Nunes (2011 ) , Tetto (2007 ) among others , have developed models for weighting and weights assigned to different levels of information which is based on each factor that affects the occurrence of fire in a particular location ( human presence , prevailing wind , combustible material , slope , vegetation cover and exposure of slopes ) through map algebra technique performed using the software " ArcGIS 9.3 ". Aerial imagery of flight state of SC for construction of cartographic base, altimetry ASTER / GDEM data and BDMEP / INMET San Joaquin to determine the prevailing winds of the region station were used, in addition to mapping data from IBGE . The product of this research are maps with six classes of forest fire risk ; zero , low, moderate , high, very high and extreme. For the boundaries of the Aguaí REBIO presented respectively the proportions of 3.4% , 42.5 % , 19.7% , 20.6 % , 9.6% , and 4.2 % from the total area of the reserve ( 7874 ha ) and 14.2 % , 30.7 % , 19.8 % , 13.4% , 16.7% and 5.1 % for the surrounding area ( 18441 ha ) . The application of the ZRIF methodology to the area of REBIO and the surrounding area offers grant to improve the management of the reserve and the surroundings. The ZRIF offers the possibility of a more assertive planning prevention and monitoring related classes of high risk on the map . The methodologies adopted have proved satisfactory for the zoning of fire risk of the REBIO Aguai and surrounding area / O zoneamento de risco de incêndios florestais (ZRIF), é uma ferramenta importante para a prevenção, monitoramento, planejamento, combate a incêndios e definição de políticas públicas relativas à manutenção do patrimônio ecológico. Os incêndios oferecem risco ao meio ambiente, além disso de acordo com sua proporção podem se tornar muito difíceis de controlar e combater. Pensando então em termos de monitoramento e prevenção surge necessidade de se desenvolver metodologias para realizar o ZRIF de reservas de florestas nativas no estado de Santa Catarina, que é o enfoque principal desta pesquisa. O trabalho foi realizado na Reserva Biológica do Aguaí que está localizado nos contrafortes da Serra Geral no sul do estado, com altitude entre 200 e 1400 m e área de 7.672 ha. A áreas de estudo foram divididas em REBIO do Aguaí com 7.874 ha e área do entorno com 18.441 ha. As áreas de estudo abrigam as nascentes que dão origem aos rios que abastecem a região sul catarinense, influenciando diretamente 450.000 pessoas. A pesquisa procurou validar e aprimorar as técnicas de ZRIF já aplicadas por autores como Oliveira (2000), Koproski (2010), Nunes (2011), Tetto (2009) entre outros, que desenvolveram modelos de ponderação e pesos atribuídos a diferentes planos de informações que tem como base cada fator que afeta a ocorrência de incêndio em um determinado local (presença humana, vento predominante, material combustível, declividade, cobertura vegetal e orientação das encostas) por meio da técnica de álgebra de mapas realizada com uso do software "ArcGis 9.3". Foram utilizadas imagens aéreas do voo do estado de SC para construção da base cartográfica, dados altimétricos ASTER/GDEM e dados da estação BDMEP/INMET de São Joaquim para determinação dos ventos predominantes da região, além de dados de cartografia do IBGE. O produto do trabalho são mapas com seis classes de risco de incêndio florestal; nulo, baixo, moderado, alto, muito alto e extremo. Para os limites da REBIO do Aguaí apresentaram respectivamente as proporções de, 3,4%, 42,5%, 19,7%, 20,6%, 9,6%, e 4,2% em relação à área total da reserva (7874 ha) e 14,2%, 30,7%, 19,8%, 13,4%, 16,7% e 5,1% para a área do entorno (18441 ha) para as classes de risco nulo, baixo, moderado, alto, muito alto e extremo respectivamente. A aplicação da metodologia de ZRIF para a área da REBIO e para área do entorno oferece subsídio para a melhoria na gestão da reserva e do entorno. O ZRIF oferece a possibilidade de um planejamento mais assertivo de ações de prevenção e monitoramento relacionadas às classes de risco elevado presentes no mapa. As metodologias adotadas se mostraram satisfatórias para o zoneamento de risco de incêndio da REBIO do Aguaí e da área do entorno
28

Comprendre les grands feux de forêt pour lutter en sécurité / Dangerous wildfire conditions for firefighters

Lahaye, Sébastien 22 October 2018 (has links)
En dépit de moyens importants consacrés à la lutte, certains feux de forêt, en Europe méditerranéenne, en Australie ou en Amérique du Nord, parcourent de grandes surfaces et développent des comportements violents qui piègent les pompiers. L’étude de rapports internes aux services d’incendie révèle ici les conditions météorologiques et topographiques dans lesquelles se produisent ces feux dangereux. En France, alors que le vent violent est le principal contributeur des feux les plus grands et les plus dangereux, les températures élevées mènent à un autre type d’incendies violents qui se propagent rapidement. En Australie, les pompiers sont souvent piégés par une bascule brutale de la direction du vent mais aussi par des vents forts en terrain accidenté. Au-delà des disparités intercontinentales, la recherche des comportements dynamiques de feu impliqués dans plus de 100 accidents de pompiers à travers le monde amène à distinguer trois types d’incendie. Lors des feux topographiques, en zone de montagne, les accidents sont généralement causés par l’attachement de la flamme sur des pentes supérieures à 20°. Lors des feux guidés par le vent, les zones les plus propices aux accidents sont les pentes déventées où des effets de vortex peuvent se produire. Enfin, lors des feux convectifs, les plus violents, les accidents peuvent se produire loin de toute configuration dangereuse. Pour tenir compte de ces résultats et améliorer leur sécurité, les pompiers doivent adapter leur formation et de développer des compétences d’analyste du feu. Ces experts intègreront les retours d’expérience des incendies passés pour proposer les stratégies de lutte les plus efficaces et sécurisées. / Despite the large expenditure that is dedicated to forest fire suppression in Euro-Mediterranean countries, Australia and North-America, firefighters still face large and severe fire events which eventually entrap them. Investigation of Fire Services’ internal reports addresses here the weather and terrain leading to these dangerous fires. In France, strong wind is the main driver of the largest fires and of the fires that entrap firefighters. However, high temperature is also a key contributor as it influences violent fires with high rates of surface spread. In Australia, a lot of firefighters’ entrapments are due to shifts in wind direction, but others are associated to strong winds in rugged terrain. Whatever the regional specificities, more than 100 firefighters’ entrapments across the world were investigated to find the contribution of dynamic fire behaviors in these entrapments. The results return three different types of fires. During topography-influenced fires, in mountainous area, almost all the entrapments happen on slopes steeper than 20°, prone to flame attachment. During wind-driven fires, leeward slopes prone to vorticity-driven lateral fire spread are the most prominent configurations associated with entrapments. Finally, during convective fires, which are the most violent, entrapments can happen far away from any dangerous configuration. Firefighters should adjust their training courses and promote fire behavior analysts (FBAN) capabilities to benefit from the results of this work and improve their safety. FBAN may consider feedbacks from previous fires to suggest the most efficient and secure firefighting strategies and locations.
29

Historique et caractéristiques écologiques des îlots résiduels après feu en forêt boréale mixte / Assessing the potential of post-fire residual patches as sanctuaries for biodiversity conservation in the boreal forest

Ouarmim, Samira 17 December 2013 (has links)
Le feu est la principale perturbation en forêt boréale mixte. La sévérité des feux n'est pas spatialement homogène et épargne souvent partiellement ou entièrement des parties de la forêt appelées îlots résiduels. Ces îlots forestiers résiduels après feux sont étudiés depuis de nombreuses années, et ces études se sont surtout intéressées aux facteurs déterminant leur occurrence à l'échelle du paysage. Cependant, les travaux réalisés en Fennoscandinavie et aux États-Unis ont révélé la présence de peuplements forestiers (appelés refuges) ayant la capacité de se maintenir dans le territoire pendant plusieurs millénaires. L'objectif principal de cette thèse était de caractériser la dynamique temporelle et la structuration d'îlots forestiers localisés au sein de la forêt boréale mixte de l'est du Canada. Treize îlots forestiers qui ont échappé au dernier feu ont été échantillonnés. Des carottes de sols ont été extraites dans chacun des sites pour réaliser des analyses paléoécologiques (charbons et macrorestes). Les caractéristiques stationnelles de chaque site ont été échantillonnées pour déterminer si les refuges se distinguent des autres îlots résiduels. La charge en combustible des îlots a également été mesurée. Les données ont également servi à alimenter des modèles numériques de comportement du feu (Fire Behavior Prediction System, BehavePlus, FlamMap3) qui ont été utilisés afin de déterminer les caractéristiques stationnelles qui permettent aux refuges d'échapper au feu de façon récurrente. Les résultats ont mis en évidence l'existence de deux types d'îlots résiduels en forêt boréale mixte : les refuges et les autres îlots résiduels. Les refuges sont moins susceptibles au feu comparativement aux îlots résiduels qui ont échappé uniquement au dernier feu, probablement de façon fortuite. Les refuges ont en revanche la capacité de persister dans le paysage forestier durant plusieurs millénaires, ne brûlant uniquement durant des feux particulièrement sévères. Les analyses macrofossiles des refuges soulignent des changements majeurs au sein de la végétation locale, avec comme événement remarquable le passage de formations dominées par Larix laricina/Picea sp. vers des formations dominées par Abies balsamea/Thuja occidentalis. Ce changement de végétation s'est produit à différentes périodes selon les sites, soulignant un processus endogène dans cette transformation de la végétation. Le développement de Larix laricina s'est accompagné dans certains assemblages macrofossiles de taxons typiques de milieux humides (tels que les characées). L'importante couche de matière organique qui caractérise les refuges semble entraver le développement d'espèces de début de succession telles que Betula papyrifera et Populus tremuloïdes. Les îlots refuges doivent leur persistance dans le paysage forestier à un certain nombre de facteurs biotiques et abiotiques qui limitent le passage du feu. Les résultats issus des simulations du comportement du feu, suggèrent un rôle mineur des coupe-feu (lacs, tourbières, et monticules rocheux essentiellement), de la charge en combustible et de la topographie dans l'occurrence des refuges. L'humidité semble être le seul facteur déterminant leur développement au sein de la mosaïque paysagère. Les refuges se mettent en place au sein de faibles dépressions humides qui favorisent l'accumulation de la matière organique. La structure des refuges et des autres îlots résiduels révèle deux principales caractéristiques permettant de les distinguer sur le terrain : le diamètre moyen des arbres et l'épaisseur de la matière organique. Les arbres des refuges ont un plus petit diamètre que ceux des autres îlots résiduels. L'importante épaisseur de la matière organique des refuges affecte négativement la croissance des arbres. Ces caractéristiques pourront être utilisées comme outils d'aide à la décision dans les stratégies d'aménagement forestier. / Fire is the main natural disturbance shaping boreal forest landscapes. In North American boreal ecosystems, wildfires contribute to the creation of a complex mosaic of stands of varying age, composition, and structure, within which other disturbances and processes can interact. A burned area usually includes tree patches that partially or entirely escaped fire, called post-fire residual patches. The spatially occurrence of post-fire residual patches has been extensively described. However, the presence of fire refuges has been reported in Fennoscandia and in United-States, which can escape fire for several millennia. The aim of this study was to characterize temporal dynamics in post fire residual patches in mixedwood boreal forest of eastern Canada. The analyses concern the reconstruction of fire and forest dynamics history though Holocene and identify characteristics features of these patches. This research aimed to contribute significantly to the objectives of ecosystemic management to preserve biological diversity in the forest mosaics.Thirteen post-fire residual patches which escaped the last fire have been sampled. At each stand, cores and monoliths were extracted for paleoecological analyses. The reconstitution of fire history and forest dynamics were studies by using macroscopic charcoals and macroremains. The characteristics features of stands were also sampled, to differentiate fire refuges from other post-fire residual patches. The fuel load was also measured, and all these data were used as inputs for fire behavior modeling (Fire Behavior Prediction System, BehavePlus, FlamMap3), to identify stand characteristics prevent fire refuges to burn in comparison with other residual stands and forest matrix.The results showed the presence in the landscaped of two types of post-fire residual patches in mixedwood boreal forest: fire refuges and other post-fire residual patches. The fire refuges present less fire susceptibility than other post-fire residual patches, which escape only the last fire probably by chance. On the other hand, fire refuges can persist in the landscape for several millennia, burning in the most severe fires. The forest dynamics reconstruction in fire refuges, highlight major shift in the vegetation from Larix laricina/Picea sp. to late successional species Abies balsamea/Thuja occidentalis. Occuring at all stands, but at different periods of Holocene, these changes can be attributed to internal processes. The presence of Larix laricina was associated to the occurrence of aquatic taxa (e.g. Characear). The late successional species (Abies balsamea/Thuja occidentalis) can persist in the landscape for several centuries due to moisture conditions. The thickness of organic matter recorded in fire refuges seems to inhibit the recruitment of early successional species such as Betula papyrifera et Populus tremuloïdes.The fire refuges owe their persistence in the landscape to abiotoc and biotic factors that limit fire occurrence. Then results obtained from fire behavior simulations, suggest a minor role of fire breaks (lakes, rocks), fuel load and topography in persistence of fire refuges. Local moisture condition seems to be key factor in their occurrence in the landscape. The fire refuges occur likely in depressions, which favor organic matter accumulation. The structure of fire refuges and other residual patches revealed two main characteristics, which distinguish between the two types of residual patches: Mean diameter of trees and thickness of organic matter. The trees of fire refuges present smaller tree diameter than other post-fire residual patches. The thickness of organic matter accumulation in fire refuges affects negatively the growth of trees. These features can be used as tools for decision support in forest management strategies.
30

Predicting temperature profiles during simulated forest fires

Enninful, Ebenezer Korsah 19 September 2006
Below-ground effects during forest fires are some of the important issues forest managers consider when conducting prescribed fire programs. Heat transfer models in soil are needed to predict temperatures in soil during forest fires. Many of the heat transfer models in soil that include the effects of moisture are complex and in most cases do not have very good predictive abilities. Researchers believe that simple heat transfer models in soil that neglect the effects of moisture could have very good predictive abilities.<p>This study presents a one-dimensional numerical model of heat transfer in dry homogenous sand. Both constant and temperature dependent thermal properties of the sand were used in order to determine which had better predictive abilities. The constant thermal properties model was also extended to a model of two-layer dry soil. A computer code written in Fortran was used to generate results from the model. A number of experiments were conducted with dry sand to validate the model. A comparison of the numerical and experimental results indicated that the temperature dependent properties model had better predictive abilities than the constant properties model. The models were found to do a good job of predicting temperature profiles and depth of lethal heat penetration at heat fluxes indicative of forest fires.<p>Experiments were also conducted to determine the effect of moisture on temperature profiles and the depth of lethal heat penetration in sand and the effect of inorganics on the spread rate of smoldering combustion in peat moss. An experimental correlation of the effects of inorganic content on the spread rate of smoldering combustion in peat moss was developed. Additionally, laboratory methods of validating models of heat transfer in soil were developed with the aim of limiting the dependence on full scale testing. Specifically the use of the cone calorimeter for validating numerical models of heat transfer in soil and the responses of forest floor soil and laboratory created soil samples to heat input were compared. The results indicated that the laboratory created soil did a very good job of mimicking the heat response of the forest floor soil with a maximum difference in lethal heat penetration of 4%.

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