O incêndio florestal é uma complexa combinação da energia liberada na forma de calor devido à combustão dos produtos oriundos da pirólise da vegetação e o transporte dessa energia para o ar e para a vegetação à sua volta. O primeiro é o domínio da química e ocorre na escala de moléculas e o segundo é o domínio da física e ocorre em escalas de até quilômetros. É a interação desses processos sobre uma ampla gama de escalas temporais e espaciais envolvidas no incêndio florestal que faz a modelagem do seu comportamento uma tarefa tão difícil. A propagação do incêndio através de vegetação rasteira e folhas mortas foi simulada numericamente usando a formulação física do WFDS. A abordagem utilizada foi tridimensional e transiente, e baseada em uma descrição dos fenômenos físicos que contribuem para a propagação de um incêndio de superfície através de uma camada de combustível. Neste cenário de incêndio, existem duas regiões: vegetação e ar, cada uma com suas propriedades físicas e químicas e, embora elas precisem ser integradas no mecanismo de solução, há diferentes fenômenos que ocorrem em cada uma. Na região de vegetação, a abordagem é representá-la como partículas submalha cercadas de ar. O caráter heterogêneo da vegetação, como sua natureza, folhagens, pequenos galhos, etc. foi levado em conta usando propriedades físicas médias características da floresta amazônica. Os fenômenos na região de vegetação são a evaporação da sua umidade, a pirólise e a transferência de calor por radiação e por convecção. Na região do ar, a combustão com chama ocorre em um ambiente turbulento, onde as transferências de calor por radiação e por convecção desempenham um papel significativo. Para incorporar a radiação dos gases de combustão, o modelo físico emprega o método de volumes finitos, que resolve a equação de transferência de calor por radiação como uma equação de transporte para um número finito de discretos ângulos sólidos, e que pode ser usado em uma ampla faixa de espessuras óticas e meios participantes. A combustão turbulenta para a fase gasosa é modelada com base no modelo Eddy Dissipation Concept (EDC). O modelo de combustão turbulenta adota a hipótese de reação química infinitamente rápida entre o combustível e o ar e é controlado apenas pela velocidade de mistura desses reagentes. Esse modelo representa bem a física de incêndios em ambientes ventilados, como é o caso dos incêndios florestais. Para incluir os efeitos do transporte turbulento é utilizado o método Large Eddy Simulation (LES), que calcula explicitamente as grandes estruturas turbulentas, mas trata a dissipação e a cascata inercial em escalas menores usando aproximações na escala submalha. As regiões de vegetação e ar trocam massa e energia. O comportamento da mistura gasosa resultante da degradação térmica da vegetação e das reações de combustão é regido pelas equações de Navier-Stokes. As equações que regem os modelos físicos são formuladas como equações diferenciais parciais que são resolvidas por métodos numéricos. O método utilizado para discretização das equações é o método de diferenças finitas em malha deslocada. O modelo numérico utilizado resolve as equações de Navier-Stokes para fluidos compressíveis usando o filtro de Favre. A dissipação de energia cinética é obtida através de um fechamento simples para a tensão turbulenta: o modelo de coeficiente constante de Deardorff. O transporte turbulento de energia e massa é contabilizado pelo uso, respectivamente, de números de Prandtl e de Schmidt turbulentos constantes. Os resultados das simulações do modelo físico descrito foram comparados aos dados experimentais obtidos em campo para a propagação do incêndio na floresta amazônica. Apesar da idealização das condições de combustível, vento e as incertezas dos dados experimentais, as previsões do modelo estão na mesma ordem de grandeza dos experimentos. As taxas de propagação do incêndio experimentais variam de 0,12 +/-0,06 a 0,35+/-0,07 m/min. Mesmo considerando-se o desvio padrão da taxa de propagação do incêndio experimental, os valores das taxas simuladas ficaram dentro do erro experimental somente em dois de sete casos. As simulações mostraram que os parâmetros importantes para o modelo são a área superficial por volume da vegetação, sua massa específica aparente e sua umidade. Como o coeficiente de absorção por radiação é função direta da massa específica aparente e da área superficial por volume da vegetação, esses parâmetros afetam o comportamento numérico do incêndio de superfície. De acordo com os resultados das simulações numéricas, a umidade da vegetação também tem importância no incêndio de superfície. A temperatura inicial da vegetação e a umidade do ar na faixa de variação analisada não influenciam a taxa de propagação do incêndio. As simulações também mostraram que o processo de radiação é muito importante, e afeta diretamente todos os demais processos e a taxa de propagação do incêndio. A convecção tem importância muito menor que a radiação na condição de ausência de vento externo. A coerência das taxas de propagação do incêndio experimental e numérica em função da massa específica aparente de material combustível e da umidade da vegetação foi investigada. O modelo numérico é coerente em todas as nove combinações de casos. Já o experimento é coerente em quatro combinações. Com base nas comparações entre cada dois casos experimentais e as respectivas simulações numéricas, nota-se que as taxas de propagação a partir das simulações numéricas foram mais coerentes que as experimentais. / Forest fire is a complex combination of energy released as heat due to the combustion of the products from the vegetation pyrolysis and the transport of this energy to the surrounding air and vegetation. The first is the domain of chemistry and occurs on the molecular scale, and the second is the domain of physics and occurs at scales up to kilometers. It is the interaction of these processes on a wide range of temporal and spatial scales involved in forest fires that makes modeling its behavior such a challenging task. The spread of fire through small plants and dead leaves was simulated numerically using WFDS physical formulation. The approach used was three-dimensional and transient, based on a description of the physical phenomena that contribute to the spread of a surface fire through a layer of fuel. In this fire scenario, there are two regions: vegetation and air, each one with its physical and chemical properties and, although they need to be integrated into the solution mechanism, there are different phenomena that occur in each one. In the vegetation region, the approach is to represent it as subgrid particles surrounded by air. The heterogeneity of the vegetation, such as its nature, leaves, twigs, etc. was taken into account by using average physical properties that are representative of the Amazon forest. The phenomena in the vegetation region are the evaporation of its moisture, pyrolysis, heat transfer by radiation and convection. In the air region, the flaming combustion occurs in a turbulent environment, and heat transfer by radiation and convection play a significant role. To incorporate the radiation from the combustion gases, the physical model employs the finite volumes method, solving the radiation transfer equation as a transport equation for a finite number of discrete solid angles, which can be used in a wide range of optical thicknesses and participating media. Turbulent combustion for the gaseous phase is modeled using the Eddy Dissipation Concept (EDC) model. The mixing controlled turbulent combustion model adopts the assumption of infinitely fast chemical reaction between the fuel and air. This model represents well the fire physics in ventilated areas, as is the case of forest fires. To include the turbulent flow effects, it is used the Large Eddy Simulation (LES) method, which explicitly calculates the large turbulent structures, but models the dissipation and inertial cascade using approximations in the sub-grid scale. The vegetation and air regions exchange mass and energy. The behavior of the gas mixture resulting from the vegetation thermal degradation and combustion reactions is governed by the Navier-Stokes equations. The equations governing the physical model are formulated as partial differential equations, which are solved by numerical methods. The method used for discretization of the equations is the finite difference method on a staggered grid. The numerical model solves the Navier-Stokes equations for compressible fluids using the Favre filter. Dissipation of kinetic energy is achieved through a simple closure for the turbulent stress: the constant coefficient Deardorff model. The turbulent transport of heat and mass is accounted for by use of constant turbulent Prandtl and Schmidt numbers, respectively. The physical model simulation results were compared to experimental data obtained in the field for the spread of fire in the Amazon forest. Despite of the idealized conditions of fuel, wind and the uncertainties of the experimental data, the model predictions and the experiments are in the same order of magnitude. Experimental rate of spread range from 0.12 +/- 0.06 to 0.35 +/- 0.07 m/min. Even considering rate of spread experimental standard deviation, simulated rate values were within experimental error only in two of seven cases. The simulations showed that the important parameters for the model are the vegetation surface area to volume ratio, its bulk density and moisture. As the radiation absorption coefficient is a direct function of vegetation bulk density and surface area to volume ratio, these parameters affect the numeric behavior of the surface fire. According to the numerical simulations results, vegetation moisture is also important in the surface fire scenario. Vegetation initial temperature and air humidity in the range analyzed does not influence the rate of spread. The simulations also showed that the radiation process is very important and directly affects all other processes and rate of spread. Convection heat transfer has much less significance than radiation heat transfer in the absence of external wind. The consistency of the experimental and numerical rate of spread, as a function of combustible material bulk density and vegetation moisture was investigated. The numerical model is consistent in all nine case combinations. The experiment is consistent in four cases. Based on comparisons between each two experiments and their numerical simulations, it is noted that the rate of spread variation from the numerical simulation is more consistent than the experimental one.

Orientador: Luiz Fernando Costa Nascimento / Resumo: O ecossistema amazônico é impactado fortemente pelas queimadas no período da estação seca com as emissões de poluentes na atmosfera. Os efeitos sobre a saúde das populações, especialmente na região do arco do desmatamento, tem sido objeto de recentes estudos. O objetivo do presente estudo é avaliar a distribuição espacial dos focos de queimadas, da morbidade por doenças cardiovasculares, e das concentrações dos poluentes PM2,5 e CO, no estado do Tocantins. Foi desenvolvido estudo ecológico com ferramentas da análise espacial. A análise utilizou o estimador de Kernel e índice de Moran (Im), além de mapas temáticos e correlação de Spearman (rs) entre as variáveis. O geoprocessamento utilizou o programa TerraView 4.2.2. Foram encontradas altas taxas de queimadas no estado e forte associação entre as queimadas e o coeficiente de Gini (rs = 0,30 e p-valor < 0,01). Foi encontrada correlação significativa entre concentrações de monóxido de carbono e internações por doenças do aparelho circulatório (rs = 0,18 e p-valor < 0,05). O índice de Moran para focos de queimadas foi Im = 0,28 com p-valor = 0,01. Foram identificadas cidades que necessitam de prioridade de intervenções. Conclui-se que é necessária uma maior fiscalização ambiental quanto ao controle de queimadas, inclusive nas áreas de preservação ambiental. / Abstract: The Amazonian ecosystem is strongly impacted by the forest fires in the dry season with emissions of pollutants into the atmosphere. The effects on population health, especially in the deforestation arc region, have been the subject of recent studies. The goal of the present study is to evaluate the spatial distribution of forest fires, cardiovascular disease morbidity, and PM2,5and CO pollutant concentrations in the state of Tocantins. An ecological study was developed with spatial analysis tools. The Kernel estimator and the Moran index (Im) were used as spatial analysis techniques, as well as thematic maps and Spearman correlation (rs) between the variables for the analysis of the results. The geoprocessing was development through the program TerraView 4.2.2. High forest fires rates in the state and strong association with the Gini coefficient (rs = 0.30 and p-value <0.01) were found. A significant correlation was found between carbon monoxide concentrations and hospitalizations for circulatory diseases (rs = 0.18 and p-value <0.05). The Moran index for forest fires was Im = 0.28 with p-value = 0.01. Cities that need priority interventions have been identified. It is concluded that a greater environmental inspection is necessary regarding the control of forest fires, including in the areas of environmental preservation. / Mestre

Memoria para optar al Título Profesional de Ingeniero Forestal / La presente Memoria de Título tiene como propósito formular estrategias que orienten una futura campaña de prevención de incendios forestales basadas en la sensibilización, en las comunas de la provincia de Melipilla, Región Metropolitana. Para tales efectos, se realizó un análisis de la población respecto al conocimiento sobre el medio ambiente, su percepción sobre los incendios forestales, la prevención y su participación en el control de incendios forestales. El estudio contempló a las comunas de Alhué, Curacaví, María Pinto, Melipilla y San Pedro, que, en su totalidad, abarcan una superficie de 406.570 ha, en las cuales se describió y analizó la ocurrencia y causalidad de incendios forestales para un período de 17 temporadas (1999/00 a 2015/16, inclusive), basándose en la información registrada por el Programa de Manejo del Fuego de la Región Metropolitana de CONAF. Las percepciones sobre la ocurrencia y causalidad de incendios forestales, así como las medidas de prevención realizadas, se evaluaron a través de encuestas y entrevistas, en donde los resultados sirvieron de base para realizar un análisis que permitiese fundamentar las propuestas para futuras campañas de prevención basados en la sensibilización. Los resultados demostraron que la población estudiada posee escaso conocimiento en materia de prevención de incendios forestales y, además, se puede constatar que las campañas anteriormente realizadas han sido de escaso aporte, en cuanto a la identificación del público objetivo, su mensaje, el medio por el cual se ha entregado el mensaje, la cobertura y el impacto deseado para sensibilizar a las personas. Las instituciones que más relaciona la población como organismos activos en la prevención de incendios forestales son CONAF y Bomberos, los que destacan por su constancia y por ser las que demuestran más interés en el tema. Por otra parte, Bomberos es identificada como la organización a la que se acude cuando se origina un incendio forestal. Finalmente, los resultados obtenidos permitieron sustentar la formulación de la propuesta de estrategia de prevención. Al respecto, se definió la línea de acción básica identificada como Educación y Difusión, en la cual se propone un protocolo del ámbito de su aplicación, con las estrategias específicas correspondientes y por último, la secuencia de acciones a desarrollar para llevar a cabo su implementación y ejecución. / The present Title Memory aims to formulate strategies for a future campaign to prevent forest fires based on sensitization, in the communes of the Province of Melipilla, Metropolitan Region, based on the sociological characterization of the population. For this purpose, an analysis of the behavior of the population was made regarding knowledge about the environment, their perception of forest fires, their perception about prevention and their participation in the prevention of forest fires. The study contemplated at the communes of Alhué, Curacaví, María Pinto, Melipilla and San Pedro, all belonging to the Province of Melipilla, which, in their totality, cover an area of 406.570 ha, in which the occurrence and causality of forest fires for a period of 17 seasons (1999/00 to 2015/16), based on information recorded by the Fire Management Program of the Metropolitan Region from CONAF. The perceptions about the occurrence and causality of forest fires and the done prevention measures were evaluated through surveys and interviews, where the results served as the basis for an analysis that would allow basing the proposals for future fire prevention campaigns based on sensibilization. The results showed that there is a population with little knowledge about forest fire prevention and it is also possible to verify that the previous campaigns have been of little contribution, as to the identification of the target public, its message, the medias by which has been delivered the message, the coverage and the impact that has been wished to achieve in the sensitivity of people. The institutions that most closely relate the population to the organisms active in the prevention of forest fires are the CONAF and the Fire Department, which stand out for their constancy and for being the ones that show more interest in the subject. The Fire Department is identified as the organization that people come to when a forest fire occurs. Finally, the obtained results allowed to support the formulation of the proposed prevention strategy. In this regard, the basic line of action identified as Education and Dissemination was defined, in which, is proposed a definition of the scope of application, the corresponding specific strategies and, finally, the protocol of actions to be developed to carry out its implementation and execution.

The vegetation of the Sydney Basin, Australia, is highly flammable and subject to a wide range of fire regimes. Sclerophyllous shrubs and sedges are common and in some vegetation types up to 70 % of fuel consumed during a fire can be live. Research into fire behaviour and fuel dynamics has been minimal. To address this issue this thesis investigated the principal factor affecting the ease of ignition and rate of combustion of individual fuel particles and fuel beds in bushfires: dead fine fuel moisture (FFM). Two common Sydney Basin vegetation types, eucalypt woodland and heathland, each with a history of problematic fire management, were measured in the field for diurnal fluctuations in FFM following rain, under conditions similar to when prescribed burns are conducted. The FFM components of current operational fire behaviour models were found to be inadequate for predictions of FFM and fire behaviour under these conditions. The equilibrium moisture content (EMC) of five fuel types from the field site was investigated in a laboratory study. An existing function describing EMC as a function of temperature and relative humidity was evaluated and found to be very accurate for these fuels. Two FFM predictive models incorporating this function were evaluated on the field data and the laboratory results were shown to be applicable to the estimation of FFM in the field. One model gave very accurate predictions of FFM below fibre saturation point, but its accuracy was reduced when screen level conditions were used instead of those measured at fuel level. A recent process-based model that accounts for rainfall showed promise for predicting when fuel is < 25 % FFM. Systematic problems with the radiation budget of this model reduced the accuracy of predictions and further refinement is required. Live fine fuel moisture content (LFMC) of common heathland shrubs and sedge was investigated over two years and found to be both seasonal and influenced by phenology. LFMC minima occurred in late winter and spring (August to October), and maxima were in summer (December to February) when new growth was recorded. The dominant near-surface fuel in mature heath was sedge. It was found to have little seasonal variation in its??? percentage dead but the percentage dead maxima occured at the same time as the LFMC minima of shrubs and sedge in both years. Simple instantaneous models for duff moisture content in woodland and heathland and LFMC and the percentage dead sedge in heathland were developed. The information gained by this study will form the basis for future development of fuel moisture models for prescribed burning guidelines and fire spread models specific to the vegetation communities of the Sydney Basin.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 55-62.

Thesis (Ph. D.)--School of Biological Sciences, Faculty of Science, University of Sydney, 1999. / Bibliography: leaves 235-260. Also available in print form.

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 16, 2010). Includes bibliographical references. Also issued in print.

Prior research in the Rhyolite Canyon area of Chiricahua National Monument (Swetnam et. al. 1989) revealed an anomalous 50 year fire-free interval between 1901 and 1851. Disruption of fire spread resulting from flooding and mass soil movement (debris flows) were postulated as potential causes of this long interval. The present study gathered additional evidence of fire and floods in the canyon system. Sampling of flood-scarred trees along stream channels successfully identified several flood events in Rhyolite canyon. Pulses of pine regeneration on debris flow deposits were associated with one of these events. However, no definitive linkage of flood events with changes in fire regime was established. Analysis of new fire scar samples combined with previous results indicated that the area affected by the change in fire regime includes the uplands between Jesse James Canyon and Rhyolite drainage. Source areas for fires prior to 1900 were not identified within the study area indicating that ignitions outside the present monument boundaries may have been important in the past. Evidence from the maximum ages of overstory conifers within Rhyolite Canyon suggests the occurrence of a major disturbance within this drainage prior to 1600.

No description available.

Thirty-eight oligotrophic lakes located around the Reservoir Gouin in central Quebec (48°N, 75°W) were sampled over three years to test the hypothesis that forest clearcutting and fires should be reflected in both higher nutrient export rates and ultimately in greater areal hypolimnetic oxygen deficit rates (AHOD). Significant differences in estimated total phosphorus export rates across treatments were found. However, no effect of clearcutting or forest fire on hypolimnetic oxygen consumption rates could be demonstrated as the result of a much greater and confounding variation in the effect of lake morphometry and the absence of information on the role of catchment-derived organic matter on the AHOD. Consequently, only lake morphometry (hypolimnetic volume to hypolimnetic surface area ratio) served as a predictor of the AHOD. Covariation of mean hypolimnetic water temperature with morphometric variables underlines the influence of lake morphometry on heat dynamics and hypolimnetic respiration rates in these lakes. / This research made considerable use of specialized data manipulation techniques involving a relational database management system, owing to the size of the dataset used (114 lake-years of data). The specific approach used in this thesis is presented in an appendix.