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Estimation des décès attribuables aux PM2.5 issues des feux de la forêt boréale du Nord du QuébecMahtlouthi, Fatma 08 1900 (has links)
Il est bien établi que l'exposition à court terme aux particules fines dans l’air ambiant en milieu urbain a des effets sur la santé. Toutefois, peu d'études épidémiologiques ont évalué la relation entre les particules fines (PM2.5) de sources spécifiques comme celles dérivées de feux de forêt et les effets sur la santé. Pour l’instant, les risques de mortalité et de morbidité associés aux PM2.5 résultant de la combustion de végétation semblent similaires à ceux des PM2.5 urbaines.
Dans le présent mémoire, nous avons comparé deux méthodes pour quantifier les risques de mortalité et de morbidité associés à l'augmentation des niveaux de PM2.5 à Montréal, dérivées de deux épisodes des feux de forêts majeurs dans le Nord du Québec. La première approche consistait à comparer les décès et les visites aux urgences observées enregistrées au cours des deux épisodes à Montréal à leurs moyennes respectives attendues durant des jours de référence. Nous avons également calculé la surmortalité et la surmorbidité prédites attribuables aux PM2.5 lors des épisodes, en projetant les risques relatifs (RR) rapportés par l’Environmental Protection Agency (EPA) des États-Unis pour les PM2.5 urbaines, ainsi qu’en appliquant des fonctions de risque estimées à partir des données estivales spécifiques à Montréal. Suivant la première approche, nous avons estimé une surmortalité de +10% pendant les deux épisodes. Cependant, aucune tendance claire n'a été observée pour les visites à l'urgence. Et suivant la 2e approche, la surmortalité prédite attribuable aux niveaux des PM2.5 dérivées des feux de forêt étaient moins élevés que ceux observés, soit de 1 à 4 cas seulement.
Une faible surmortalité attribuable aux niveaux élevés des PM2.5 issues de feux de la forêt boréale du Québec a été estimée par les fonctions de risque ainsi que par la méthode de comparaison des décès observés aux moyennes attendues, sur l’Île de Montréal, située à des centaines de km des sites de feux. / The association between adverse health effects and short term exposure to urban particulate matter in ambient air is well established. Few epidemiological studies have assessed the relation between fine particles (PM2.5) of specific sources like forest fires, and health effects. According to the published literature to date, risks of mortality and morbidity associated with PM2.5 from combustion sources appear similar to those of urban PM2.5. In the present thesis, we compared two methods to quantify mortality and morbidity risks associated with the increase in PM2.5 levels in Montreal, due to two major forest fire episodes in Northern Quebec. In the first approach we compared mortality and emergency room visits counts recorded during the episodes to their respective averages expected on “usual” days. We also calculated deaths and emergency room visits attributable to PM2.5 levels on episode days, using the range of relative risks (RRs) reported by the United-States Environmental Protection Agency (EPA) for urban PM2.5 levels, as well as specific risk functions developed with Montreal summer data.
With the first method, increases of deaths of more than 10% were observed for both episodes. However no clear tendency was observed in emergency room visits. Estimated attributable deaths associated with the increase in PM2.5 levels were smaller than those observed and ranged between 1 to 4 cases.
PM2.5 from Quebec boreal forest fires were associated with small increases in mortality estimated either with the risk function method or by contrasting observed deaths on “episode” days to“usual” days, on the Island of Montreal, hundreds of kilometers away from the fire sites.
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A fire management environmental decision support system for the uKhahlamba Drakensberg Park World Heritage Site.Holmes, Colin. January 2011 (has links)
Fire is a major disturbance force that affects global ecosystems and associated biomes and plays a pivotal role in the determination of ecosystem structure, functionality and dynamics. Anthropogenic environmental disturbances have resulted in shifts in fire regimes and the biogeochemical processes of these ecosystems are thus unable to function as they have done in the past, impacting both floral and faunal species. Therefore there is a need for anthropogenic management. Prescribed burning is one of the few beneficial fire management options available to decrease the severity of wildfires, decrease the associated costs in suppressing these fires and restore fire-dominated ecosystems.
The uKhahlamba Drakensberg Park World Heritage Site (UDP-WHS) is predominantly managed for water resource and nature conservation, and fire hazard reduction. It is divided into management compartments in which prescribed management burns are conducted, (i.e. manager’s burn by compartment). These compartments are subdivided by three altitudinal belts (alpine, sub-alpine and montane). Each of these belts contains different vegetation communities and therefore requires different fire regimes. However these compartments do not coincide with the natural contours and consequently, the altitudinal belts of the Park. This is problematic for management as a certain percentage per altitudinal belt is required to be burnt annually. When burning a compartment that falls within two or more belts, the total area of that compartment needs to be sub-divided into its respective altitudinal belts as a whole compartment can be prescribed to burn not a sub-division thereof.
A fire management environmental decision support system (EDSS) was developed to achieve prescribed burning objectives in the UDP-WHS. The system is based on ecologically ideal fire regimes and fire management objectives of the heritage site, using GIS and associated graphs to visually display the required fire regimes. The EDSS data preparation, statistical analysis and modelling was completed using ESRI ArcGIS suite (ArcMap, Scene and Catalog). Its main components are two models, an excel spreadsheet and an ArcMap document. The spreadsheet contains the historical burning data of the management compartments based on the compartment codes, with each compartment being not burnt or having a burning treatment. Years Since Last Burnt (YSLB) was calculated from these data and joined to the management compartments in the ArcMap document. The Intermediate output model was developed to create numerous temporary outputs allowing decision makers to decide which compartments to treat with prescribed burning by re-running the model with required alterations. The second model (Final Output model) is then run to export the selected burning treatment in table format to update the original historical data, and consequently YSLB, in the excel and ArcMap document. The ArcMap document contains the user interface housing the graphs for each altitudinal belt showing the percentage area selected to be burnt per YSLB compared to the minimal, maximum and ideal fire regimes. The fire management EDSS for the UDP-WHS consists of an ArcMap document, geodatabase, excel document and folders, which are all housed in one single folder. The use of GIS and EDSSs in environmental management improves the efficiency and accuracy of the decision making process and provides the ability to validate outputs. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
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Spatial-temporal analysis of moving polygonsRobertson, Colin John 06 April 2010 (has links)
There are few methods available for the spatial-temporal analysis of polygon data. This research develops a new method for spatial-temporal analysis of moving polygons (STAMP). Using an event-based framework, polygons from neighboring time periods are related by spatial overlap and proximity. The proximity spatial relation is defined by an application specific distance threshold. STAMP is demonstrated in the spatial-temporal analysis of a wildfire burning over small spatial and temporal scales, and in the spatial-temporal analysis of mountain pine beetle (Dendroctonus ponderosae Coleoptera: Hopkins) movement patterns over large spatial and temporal scales. The mountain pine beetle analysis found that short range movement patterns of mountain pine beetles occurred at different beetle population levels. Spot proliferation occurred most when beetle presence was increasing slowly, perhaps moving into new areas for the first time. When beetle presence increased rapidly, local expansion, or spot growth, was a more common movement pattern. In the Pine Pass study area. long range dispersal markedly extended the northeast border of the mountain pine beetle range.
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Visualisation techniques for the computer simulation of bushfires in two dimensionsFrench, Ian, Dept. of Computer Science, Australian Defence Force Academy, UNSW January 1992 (has links)
This thesis examines techniques that provide a method of computer visualisation of bushfire spread. Existing techniques studied include, Kourtz & O???Regan, Green???s Contact, Heat Accumulation, Percolation modelling and Huygens??? Principle by Anderson et.al., French, Roberts, Richards. Many of these techniques are extended as part of a comprehensive study into how they perform in a two dimensional reference frame (ie over flat terrain only). New techniques are defined for Percolation Modelling and Huygens??? Principle. Each technique is examined in a series of test cases which include computer simulations with no wind, constant wind, variable wind, variable vegetation (including patchy fuel and two fuels) and where fuel burns out. These test cases provide: (a) an incremental approach to understanding the operation of each technique; (b) a basis for comparison; and (c) verification of correctness of the technique in two dimensions. Several of the techniques are shown, by these test cases, to be equivalent. For instance, the Kourtz & O???Regan technique using a square template is equivalent to the Contact Technique, Site percolation is similar to the Heat Accumulation technique and Template percolation is similar to the Contact Technique. Overall the Huygens??? Principle techniques provide the most accurate simulations of bushfire spread.
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Artificial neural networks to detect forest fire prone areas in the southeast fire district of MississippiTiruveedhula, Mohan P., January 2008 (has links)
Thesis (M.S.)--Mississippi State University. Department of Geosciences. / Title from title screen. Includes bibliographical references.
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Evaluation des effets des incendies sur la capacité de protection des forêts contre les chutes de blocs dans les Alpes françaises / Assessing wildfires effects on the protection capability of forests against rockfalls in the French AlpsDupire, Sylvain 13 April 2018 (has links)
Les chutes de blocs constituent un aléa naturel majeur dans les Alpes françaises en raison de leur probabilité d'occurrence spatiale et temporelle très élevée. Les forêts peuvent constituer une solution naturelle et efficace pour atténuer ce phénomène tout en protégeant les populations et leurs infrastructures. Cependant, ce service écosystémique peut être perturbé par d'autres aléas naturels comme les feux de forêts, susceptibles d'être plus fréquents et intenses dans le contexte actuel et futur de changements climatiques.Cette thèse propose ainsi d'évaluer les effets des incendies sur la capacité de protection des forêts contre les chutes de blocs dans les Alpes françaises.Une méthodologie pour évaluer la capacité de protection d'une forêt contre les chutes de blocs est d'abord développée et consiste à utiliser des simulations de propagation de chutes de blocs réalisées sur 3886 placettes forestières des Alpes françaises pour calculer trois indicateurs quantitatifs évaluant la réduction de la fréquence (BARI), de l'intensité (MIRI) et la réduction globale (ORPI) de l'aléa chutes de blocs dues à la présence d'une forêt. Ces indicateurs sont utilisés pour identifier les variables forestières prépondérantes pour évaluer la capacité de protection : la longueur boisée sur le versant, la surface terrière et le diamètre moyen. Les peuplements présentant une distribution hétérogène des diamètres et composés de plusieurs essences offrent généralement une meilleure protection que les peuplements monospécifiques et réguliers, soulignant ainsi l'influence de la diversité forestière. Cette thèse montre ainsi que les taillis présentent les capacités de protection les plus élevées, suivis par les futaies feuillues et les futaies mixtes ; les peuplements résineux venant en dernier.Les évolutions spatiales et temporelles des conditions climatiques favorables aux incendies, étudiées sur la période 1959-2015, révèlent un contraste majeur entre les Alpes du Sud qui ont connu une forte augmentation (en intensité, fréquence, durée et saisonnalité) surtout à haute altitude, et les Alpes du Nord, où une légère hausse est observée à basse altitude, mais aucune tendance significative n'est observée à haute altitude. Ces résultats sont ensuite utilisés pour définir trois types de feux (d'hiver, d'été moyen et d'été très sec) pour lesquels la mortalité post-incendie est étudiée à l'échelle de l'arbre et du peuplement forestier. Ces analyses montrent que seuls les feux d'été sont susceptibles d'affecter significativement les peuplements, en particulier à basse altitude où les peuplements feuillus (notamment les taillis) dominent.L’effet des incendies sur la capacité de protection des forêts est évalué en comparant les simulations de propagation de chutes de blocs sans feu aux simulations après chaque type de feu pour lesquelles les arbres avec une forte probabilité de mortalité post-feu ne sont pas pris en compte. Les valeurs de ORPI pour chaque placette forestière et chaque type de feu sont ainsi calculées et comparées au scénario de référence sans feu, permettant ainsi d'évaluer quantitativement la réduction de la capacité de protection. Les peuplements de basse altitude, soumis à des conditions climatiques plus chaudes et sèches, présentent des réductions de la capacité de protection après des feux d'été de l'ordre de 60 à 100 %. Il s'agit principalement de taillis et de futaies feuillues. À plus haute altitude, la réduction est de l'ordre de 30 à 65 %.En conclusion, ce travail de thèse propose une méthode originale pour quantifier la capacité de protection d'une forêt contre les chutes de blocs avant et après un incendie et alimente les connaissances sur ces deux aléas naturels et les risques associés. L'analyse multi-aléas conduite en fin de thèse permet d'appréhender les effets cascades potentiels à l'échelle du peuplement forestier et de quatre territoires bioclimatiquement homogènes des Alpes françaises. / Rockfalls are a major natural hazard in the French Alps due to their high probability of spatial and temporal occurrence. Forests constitute an efficient nature-based solution to mitigate this hazard while protecting human lives and assets. However, this ecosystem service may be disrupted by others natural hazards such as wildfires likely to be more frequent and intense in the current and future context of climate changes.This PhD thesis proposes to assess the effects of fires on the protection capability of forests against rockfalls in the French Alps.A methodology to evaluate the protection capability of a forest against rockfalls is first developed. It consists in modeling rockfalls propagations on 3886 forest plots taken in the French Alps to calculate three quantitative indicators that assess the reduction of the frequency (BARI), the intensity (MIRI) and the overall reduction (ORPI) of rockfalls due to the presence of a forest. These indicators are used to identify the predominant forest variables for assessing the protective effect: the length of forest along the slope, the basal area and the mean diameter. Forest stands with a heterogeneous distribution of diameters and made up of several tree species generally offer a better protection than monospecific and regular stands, thus underlining the influence of forest diversity. This work shows that coppices have the highest protection capabilities, followed by hight stands dominated by deciduous species and mixed stands; coniferous stands coming last.Spatio-temporal trends in fire weather in the French Alps are investigated over the period 1959-2015 and reveal a major contrast between Southern Alps which experienced a strong increase (in intensity, frequency, duration and seasonality) especially at high elevation, and Northern Alps, where a slight increase at low elevation and no significant trends at high elevation are observed. These results are then used to define three types of fires (winter, summer, and dry summer) for which post-fire tree mortality is studied at the tree and forest stands levels. These analyses show that only summer fires are likely to significantly affect the forest ecosystems, particularly at low elevations where deciduous stands (especially coppice) dominate.The effect of fires on the protection capabilities of forests is assessed by comparing rockfalls propagation simulations without fire to simulations after each type of fire in which the trees with a high post-fire mortality are not taken into account. The ORPI values for each forest plot and fire type are thus calculated and compared to the reference scenario without fire thus making it possible to quantitatively assess the reduction of the protection capabilities. Low elevation stands, subject to warmer and drier climatic conditions, show reductions of the protective effect in the range 60-100%. It mainly concerns coppices and deciduous stands. At high elevation, the reduction is in the range 30- 65%.In conclusion, this PhD thesis proposes an original method to quantify the protection capabilities of a forest against rockfalls before and after a fire and improve the knowledge of these two natural hazards and their associated risks. The multi-hazard analysis conducted at the end of the thesis makes it possible to understand the potential cascading effects in the main forest types and for four bioclimatically homogeneous territories of the French Alps.
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Análise espacial e temporal de incêndios florestais para o Município de Inhambupe, litoral norte da Bahia / Spatial and temporal analysis of forest fires for the city of Inhambupe, north coast of BahiaWhite, Larissa Alves Secundo 25 February 2013 (has links)
Every fire on the forest environment that escapes man's control is called forest fire. Despite the fire being a natural agent within ecosystems, when badly managed, can cause damage that involve environmental sphere as well as the economic and social. From the knowledge of the power of fire destruction emerges the sense of establishing prevention and fighting forest fires. In order to improve prevention activities in eucalyptus plantations of the city of Inhambupe was performed the estimate probability of fire occurrence and modeling forest fire risk. For this, initially, through the use of climatic variables, indexes of Angstron, Logarithmic of Telicyn, Rodríguez and Moretti, Nesterov, and the formulas of Monte Alegre and Monte Alegre Altered were compared, based on the evaluation of the Heidke Skill Score. Subsequently, the modeling of forest fire risk map was performed by developing and integrating preliminary risk maps of natural and social variables: slope, urban area, road system, network watershed, appearance and soil use and occupancy. Finally, both approaches was compared to historical occurrences of forest fires and registry of burned areas in plantations of eucalyptus, for the purpose of determined the applicability of them. By the obtained data it was determined for the city of Inhambupe that the Logarithmic of Telicyn Index and the adjusted Formula of Monte Alegre was appropriate to determine the probability of forest fires. Furthermore, it was shown that more than 75% of the area is at risk of "high" to "extreme" of the emergence and development of the same / Todo fogo no ambiente florestal que foge do controle do homem é denominado de incêndio florestal. O fogo, apesar de ser um agente natural presente nos ecossistemas, quando mal manejado, pode causar danos que englobam tanto a esfera ambiental quanto a econômica e a social. É a partir do conhecimento desse poder de destruição que se desperta o sentimento de se estabelecer ações de prevenção e combate aos incêndios florestais. Visando aprimorar ações de prevenção, em povoamentos de eucalipto presentes no município de Inhambupe, foram realizadas a estimativa da probabilidade de ocorrência e a modelagem do risco de incêndio florestal. Para isso, inicialmente, por meio da utilização de variáveis climáticas, foram comparados os índices de Angstron, Logarítmico de Telicyn, Rodríguez e Moretti, Nesterov, e as fórmulas de Monte Alegre e Monte Alegre Alterada, baseados na avaliação do Skill Score de Heidke. Posteriormente, foi realizada a modelagem do mapa de risco de incêndio florestal, mediante a elaboração e integração de mapas preliminares de risco de variáveis naturais e sociais: inclinação, área urbana, sistema viário, malha hidrográfica, aspecto e uso e ocupação do solo. Por fim, ambas as metodologias foram comparadas ao histórico de ocorrências de incêndios florestais e ao registro de áreas queimadas, oriundos de plantios de eucalipto, a fim de determinar a aplicabilidade das mesmas. Mediante os dados obtidos, determinou-se para o município de Inhambupe o Índice Logarítmico de Telicyn e a Fórmula de Monte Alegre ajustada como adequadas para estimar a probabilidade de ocorrência de incêndios florestais. Além disso, foi evidenciado que mais de 75% da área encontra-se em risco alto a extremo de surgimento e desenvolvimento dos mesmos
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Dlouhodobá dynamika disturbancí smrkových lesů ve Vysokých Tatrách / Long-term disturbance dynamics of spruce forest in High Tatra Mts.Beranová, Jana January 2018 (has links)
Spruce forest is an important production ecosystem for our civilization. Its development can be affected by three main types of disturbances: forest fire, windstorms and spruce bark beetle attack. Experiences with a massive and long-term attack of spruce bark beetle in the Šumava mountains and a strong windstorm in 2004 in the spruce forest in the High Tatra provoke questions, how natural are such severe disturbances. To understand the current development of forest ecosystems, it is necessary to study past structure of these forests and frequency of forest disturbances. This work is about locality Tatranská Lomnice located in the High Tatra mountains, in the belt of mountain spruce forest. In my work, I used mainly pollen and plant macro-fossils analyses. I compared my data with disturbance information originating from dendroecology for windstorms and from charcoal analysis for fires. My research found that according to the pollen assemblages, most of the disturbances did not have strong influence on the forest composition, and most likely they only caused the forest thinning. The most significant fire occurred around 1420. The most significant wind disturbance probably occurred in 1890. The was not found any effect of spruce bark beetle. In the past millennium disturbances affected spruce forest...
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Análise espacial e temporal de incêndios florestais para o Município de Inhambupe, litoral norte da Bahia / Spatial and temporal analysis of forest fires for the city of Inhambupe, north coast of BahiaWhite, Larissa Alves Secundo 25 February 2013 (has links)
Every fire on the forest environment that escapes man's control is called forest fire. Despite the fire being a natural agent within ecosystems, when badly managed, can cause damage that involve environmental sphere as well as the economic and social. From the knowledge of the power of fire destruction emerges the sense of establishing prevention and fighting forest fires. In order to improve prevention activities in eucalyptus plantations of the city of Inhambupe was performed the estimate probability of fire occurrence and modeling forest fire risk. For this, initially, through the use of climatic variables, indexes of Angstron, Logarithmic of Telicyn, Rodríguez and Moretti, Nesterov, and the formulas of Monte Alegre and Monte Alegre Altered were compared, based on the evaluation of the Heidke Skill Score. Subsequently, the modeling of forest fire risk map was performed by developing and integrating preliminary risk maps of natural and social variables: slope, urban area, road system, network watershed, appearance and soil use and occupancy. Finally, both approaches was compared to historical occurrences of forest fires and registry of burned areas in plantations of eucalyptus, for the purpose of determined the applicability of them. By the obtained data it was determined for the city of Inhambupe that the Logarithmic of Telicyn Index and the adjusted Formula of Monte Alegre was appropriate to determine the probability of forest fires. Furthermore, it was shown that more than 75% of the area is at risk of "high" to "extreme" of the emergence and development of the same / Todo fogo no ambiente florestal que foge do controle do homem é denominado de incêndio florestal. O fogo, apesar de ser um agente natural presente nos ecossistemas, quando mal manejado, pode causar danos que englobam tanto a esfera ambiental quanto a econômica e a social. É a partir do conhecimento desse poder de destruição que se desperta o sentimento de se estabelecer ações de prevenção e combate aos incêndios florestais. Visando aprimorar ações de prevenção, em povoamentos de eucalipto presentes no município de Inhambupe, foram realizadas a estimativa da probabilidade de ocorrência e a modelagem do risco de incêndio florestal. Para isso, inicialmente, por meio da utilização de variáveis climáticas, foram comparados os índices de Angstron, Logarítmico de Telicyn, Rodríguez e Moretti, Nesterov, e as fórmulas de Monte Alegre e Monte Alegre Alterada, baseados na avaliação do Skill Score de Heidke. Posteriormente, foi realizada a modelagem do mapa de risco de incêndio florestal, mediante a elaboração e integração de mapas preliminares de risco de variáveis naturais e sociais: inclinação, área urbana, sistema viário, malha hidrográfica, aspecto e uso e ocupação do solo. Por fim, ambas as metodologias foram comparadas ao histórico de ocorrências de incêndios florestais e ao registro de áreas queimadas, oriundos de plantios de eucalipto, a fim de determinar a aplicabilidade das mesmas. Mediante os dados obtidos, determinou-se para o município de Inhambupe o Índice Logarítmico de Telicyn e a Fórmula de Monte Alegre ajustada como adequadas para estimar a probabilidade de ocorrência de incêndios florestais. Além disso, foi evidenciado que mais de 75% da área encontra-se em risco alto a extremo de surgimento e desenvolvimento dos mesmos
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Avaliação e simulação do comportamento do fogo no refúgio de vida silvestre Mata do Junco, Sergipe, Brasil / Characterization and simulation of fire behavior in a wildlife refuge Mata do Junco, Sergipe, BrazilOliveira, Marcus Vinicius Noronha de 24 February 2016 (has links)
Forest fires are one of the most serious environmental problems of today's world, caused,
mainly, from the misuse of fire in agricultural activities. Studies show that they have direct
influence on the biodiversity reduction and in the increase of greenhouse effect, beside
negatively affect soil fertility. The situation is even more serious when the fire reaches
conservation areas. In Sergipe, areas of preserved Atlantic Forest share spaces with sugarcane
monoculture, in which, every year, control burns are carried out during the harvest procedure.
This misuse of fire is responsible for environmental problems every year. Therefore,
researchers have been working to understand the main factors that contribute to the higher
incidence of forest fires, seeking to better predict the fire behavior and thus, establish more
effective fire prevention programs. This work fits in this perspective and has as objective,
quantify the surface fuel load and assess the fire behavior in different vegetation types of the
Wildlife Refuge Mata do Junco, Capela, Sergipe, thus generating important knowledge for
science and useful information for the design of an operational plan to prevent forest fires in
the region. The study area with approximately 897 ha, has a relevant ecological interest. Rare
and endemic species such as the Callicebus coimbrai are present there, as also the Lagartixo
river, an important stream that supply water for the region. As methodology, the sampling
fieldwork were done from January to October 2015, in three different vegetation types:
Bamboo Fields, Closed Forests and Transition Areas, were 60 samples of surface fuel load
were collected and classified according to the Rothermel (1972) model. The fuel moisture
content and climate variables as air temperature and air relative humidity were also measured
during the sampling procedure. All the fuel load collected was properly labeled and used
during the experimental burns. All the data were stored in Excel 2007 and processed in the
JMP 10.0 software. The fire behavior during the experimental burns was compared with
simulations using the software Eucalyptus Fire Safety System 1.0 and the BehavePlus 5.0 in
order to evaluate their efficiency. The total fuel load collected weighted 117,23 kg with an
average moisture content of 35,40%, equivalent to an average of 16,68 t/ha of dry fuel load.
The Bamboo Fields were defined as the vegetation type most susceptible to forest fires
occurrence and were the fire is more intense and difficult to control. It is expected that the
results from this work can contribute to the knowledge of the fire behavior in the study area
and, therefore, to the protection of this important patch of Atlantic Forest in the state of
Sergipe. / Os incêndios florestais são um dos problemas ambientais mais graves do mundo atual, sendo
originados, principalmente, a partir do mau uso do fogo em atividades agropecuárias. Estudos
comprovam que eles têm interferência direta na redução da biodiversidade e na emissão de
gases de efeito estufa, além de alterar negativamente a fertilidade do solo. Isso fica ainda mais
grave, quando as propriedades agropecuárias fazem fronteira com áreas naturais protegidas.
Em Sergipe, remanescentes de Mata Atlântica dividem espaços consideráveis com
monoculturas de cana-de-açúcar, nas quais, todos os anos, são realizados processos de queima
controlada antes da colheita. Este emprego do fogo é responsável por problemas ambientais
todos os anos. Diante disso, pesquisadores têm se dedicado a compreender os principais
fatores que contribuem para a maior ocorrência de incêndios florestais, buscando assim,
estabelecer mecanismos de predição do comportamento do fogo e, consequentemente,
estabelecer programas de prevenção mais eficientes. O presente trabalho se insere nessa
perspectiva, tendo por objetivo quantificar o material combustível superficial e avaliar o
comportamento do fogo em diferentes fitofisionomias do Refúgio de Vida Silvestre Mata do
Junco, Capela, Sergipe, gerando assim, conhecimentos importantes para a Ciência, além de
informações úteis para a elaboração de um plano operacional de prevenção e combate aos
incêndios florestais na região. A área de estudo, com aproximadamente 897 ha, apresenta um
relevante interesse ecológico, sob a qual é possível encontrar espécies raras e endêmicas como
o Callicebus coimbrai (macaco-guigó), ou ainda, nascentes de riachos importantes para o
abastecimento da região, como as do Riacho Lagartixo, por exemplo. Como metodologia,
foram realizadas incursões a campo de Janeiro a Outubro de 2015, onde foram coletadas 60
amostras de material combustível superficial, classificadas de acordo com o modelo de
propagação do fogo estabelecido por Rothermel (1972), em três distintas fitofisionomias:
Bambuzal, Mata Fechada e Área de Transição. Também foram mensurados o teor de umidade
do material combustível e as variáveis climáticas temperatura e umidade relativa do ar no
momento da coleta. Todo o material coletado foi devidamente etiquetado e utilizado para as
queimas experimentais. Os dados obtidos foram armazenados em planilhas do Excel 2007 e
processados no software JMP 10.0. O comportamento do fogo durante as queimas
experimentais foi comparado com simulações utilizando-se os softwares Eucalyptus Fire
Safety System 1.0 e o BehavePlus 5.0, a fim de avaliar a eficiência dos mesmos. No total,
foram coletados 117,23 Kg de material combustível úmido nos ambientes selecionados para
esse estudo, que apresentou teor de umidade médio de 35,40%, o equivalente a uma média de
16,70 t/ha de material combustível seco. As áreas de Bambuzal foram definidas como as mais
susceptíveis à ocorrência de incêndios florestais, sendo estes de elevada intensidade e difícil
controle. As Áreas de Transição também apresentaram valores elevados de velocidade de
propagação do fogo. No entanto, a baixa carga de material combustível nessas áreas sugere
um padrão de incêndios de curta duração. Espera-se que os resultados obtidos através desse
trabalho possam contribuir significativamente para o conhecimento de parâmetros inerentes
ao comportamento do fogo na área de estudo e, consequentemente, para a proteção desse
importante fragmento de Mata Atlântica do estado de Sergipe.
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