Based on wildfire data acquired from Mississippi forestry commission from 1991- 2005 approximately 4,000 wildfires occur in Mississippi each year, burning over 60,000 acres of forest and grassland. This study focuses on Mississippi’s wildfires from 1991- 2005 for the summer/fall period defined for this study as the May-November fire season. Statistical analysis indicates that there is significant correlation between vegetation indices derived from remotely sensed data and wildfire size at various time lag periods. Forest areas are correlated with vegetation indices at longer lag periods, nonorested areas are correlated at shorter lag periods. The inverse correlation between wildfire size and vegetation indices shows that vegetation greenness is an indicator of wildfire potential. This result can be implemented as management tool knowing that changes in vegetation vigor in certain areas of the state may increase wildfire potential in those areas and use of prescribed burnings may reduce the wildfire potential in those areas.

6 pp. / Firewise Series / This bulletin describes the specific characteristics and fire history of Arizona interior chaparral which distinguish it from California chaparral, and provides landscaping guidelines both to mitigate structural damage from wildfire and to maintain the health of this important vegetation type.

Calorimetry, the science of measuring heat from chemical reactions and physical changes, is one to the most valuable tools fire safety engineering have at their disposal. Calorimetric devices such as the cone calorimeter and the fire propagation apparatus (FPA) give us the means to evaluate and understand how different materials burn at a small scale. Due to fire being affected by many different environmental factors, these devices help us to isolate and examine how each factor affects fire as a whole and be able to apply this knowledge to tools that can be used at larger scales. This thesis reports various pieces of work on different calorimetric studies done on cellulosic material used in today’s natural and built environment. All experimental tests herein are done using the FPA, the state of the art calorimeter for fire safety studies. The experimental techniques presented here show how invaluable calorimetry is in giving us key insights on the combustion dynamics of fire related processes. The thesis is presented in manuscript style. Each chapter is a stand alone research work intended for publication with the exception of the first and last chapter; intended to introduce these and their relevance to the science and the last to summarize on overall findings and recommended improvements. Chapter 2 presents a study on the burning of live and dead pine needles. Pine forests present a relatively high flammability risk comprised in great part by pine needles. Different moisture content, flow conditions and their interrelationship is studied on the different parameters affecting the combustion processes. Overall, the results show that fire physics and chemistry vary with fuel and flow conditions and that moisture content is not the only difference between live and dead fuels but that the needle bed physiochemical mechanisms matter as well. This is the first time calorimetry data is presented on the burning of live and dead pine needles. Chapter 3 complements chapter 2 with an added in-depth analysis on the effect of different pine needle species, fuel load and imposed heat insult. Interrelationship between these variables is shown to have a strong effect on the overall combustion process. Fuel load is shown to be an essential condition to know as it gives a direct indication on the intensity of the fire. Flow is shown to have a varied effect depending on the fuel load, it can either aid or be detrimental to the overall combustion process especially relating to ignition times. Chapter 4 is a study on the effect of leaf morphology to flammability of different natural fuels. This study is a direct extension of the work presented in the paper Belcher et al (2010) in Nature Geoscience. Representative natural fuel samples from the Triassic/Jurassic Boundary, a time period of great importance because it marked a time of major environmental changes, are used to evaluate fire activity as a whole during this time period. The study shows that smaller leaf area and larger surface area to volume ratio show a strong correlation to an increase in flammability of these fuels. The research presents new insight into how leaf morphology can be used as a tool to assess the effect of fire activity around the globe and how closely vegetation is linked to this. Chapter 5 presents a study on flammability of chipboard. Wood being an inhomogeneous, non-isotropic material presents researchers with a complex problem due to its burning behavior. Wood has been a preferred construction material since far back and is widely used in construction today. Different oxygen levels, heat insults, material thicknesses and densities and the interrelationship between these variables are assessed to observe the effect on the flammability of chipboard. Density and thickness is shown to have little effect on the overall burning dynamics with thermally thick samples apart from the increased fuel content. Oxygen levels and imposed heat insults, however, show a wide range of effects and the interrelationship proves to be quite important during the combustion process. The research outlines how char formation is affected by the different variables and how important this process becomes along the overall combustion process. Calorimetric studies are presented that illustrate the use of these devices to study the effect of varying environmental conditions and the importance of their interrelationships on both natural and built environment fuels. The works highlight the importance of first establishing the dynamics of the combustion process in order to be able to extract combustion parameters that are needed for modeling fires better in both wildland and built environments.

Wildfires have become more destructive and are seriously threatening societies and our ecosystems throughout the world. Once a wildfire escapes from its initial suppression attack, it can easily develop into a destructive huge fire that can result in significant loss of lives and resources. Some human-caused wildfires may be prevented; however, most nature-caused wildfires cannot. Consequently, wildfire suppression and contain- ment becomes fundamentally important; but suppressing and containing wildfires is costly. Since the budget and resources for wildfire management are constrained in reality, it is imperative to make important decisions such that the total cost and damage associated with the wildfire is minimized while wildfire containment effectiveness is maximized. To achieve this objective, wildfire attack-bases should be optimally located such that any wildfire is suppressed within the effective attack range from some bases. In addition, the optimal fire-fighting resources should be deployed to the wildfire location such that it is efficiently suppressed from an economic perspective. The two main uncertain/stochastic factors in wildfire management problems are fire occurrence frequency and fire growth characteristics. In this thesis two models for wildfire management planning are proposed. The first model is a strategic model for the optimal location of wildfire-attack bases under uncertainty in fire occurrence. The second model is a tactical model for the optimal deployment of fire-fighting resources under uncertainty in fire growth. A stochastic mixed-integer programming approach is proposed in order to take into account the uncertainty in the problem data and to allow for robust wildfire management decisions under uncertainty. For computational results, the tactical decision model is numerically experimented by two different approaches to provide the more efficient method for solving the model.

Thesis (MS)--University of Montana, 2009. / Contents viewed on February 11, 2010. Title from author supplied metadata. Includes bibliographical references.

Trends indicate that wildfires have become larger and more intense over the past few decades. Experts suggest this is due to multiple factors including long-term shifts in land use that disrupt the balance of fuels and fire regimes. Research predicts that climate change will exacerbate this trend but will do so in spatially variable ways across the globe, causing increases in fire activity for some regions and decreases for others. In the United States, increased wildfire activity combined with the rapid expansion of residential development in fire-prone land necessitate billions of dollars in suppression efforts every year to protect human lives and property. The confluence of these issues has catalyzed momentum for communities to actively participate in mitigation at the local level. Yet, the precursor to developing effective solutions is to understand the unique environmental and social components of wildfire hazards at local and regional scales and how these components influence the deleterious impact of fire. This thesis takes a case study approach to understanding and communicating wildfire hazard potential in the Edwards Plateau ecoregion of central Texas. Wildfire simulations were conducted at the regional scale to quantify the magnitude of predicted fire behaviors under various spatial and temporal conditions. Simulations were also conducted within two focal communities to illuminate how patterns of wildfire susceptibility overlap with residential development. Finally, an investigation was made into the emergency response infrastructure and mitigation strategies adopted by each of the focal communities. As a result of simulations under drought conditions, forty-four percent of the study area exhibited flame lengths over eleven feet and ninety-six percent of the tree canopy exhibited crown fire activity. Simulations also revealed an increased potential for crown fire activity and extreme flame lengths along the heavily-populated Balcones Escarpment. Third, physical forms of communities appeared to influence the spatial distribution of burn susceptibility. Finally, the infrastructure and practices of the surrounding region impacted community resilience to wildfire hazards. While these findings are specific to the eastern Edwards Plateau, they showcase how mixed methods can be used to build a comprehensive wildfire hazard assessment for a community. / text

Thesis (Ph. D., Natural Resources)--University of Idaho, November 15, 2007. / Major professor: James R. Fazio. Includes bibliographical references (leaves 66-76). Also available online (PDF file) by subscription or by purchasing the individual file.

Thesis (M.A.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 68-72). Also available online.

To investigate the prevalence and magnitude of hydrophobicity in near-surface peat, a poor fen was characterized into four main post-fire microforms: i) severely burned hollows (SB-H), ii) severely burned Sphagnum fuscum hummocks (SB-Sf), iii) lightly burned S. fuscum hummocks (LB-Sf) and, iv) lightly burned feathermoss lawns (LB-F). The SB-H possessed the most hydrophobicity at the surface (85 ± 20 s) and increased at the 2 cm depth (183 ± 35 s). In comparison, the LB-F experienced an increase in hydrophobicity from the surface (44 ± 10 s) to 5 cm (323 ± 32 s) and remained high to the 10 cm depth (211 ± 31 s). Results on Sphagnum recovery show that only LB-Sf are recovering and the SB-H show marginal recovery of pioneer species such as Ceratodon purpureus and Polytrichum strictum. Moreover, S. fuscum had a mean surface cover of 56 ± 5.9% in the LB-Sf and both pioneer species together possessed a total cover of 15 ± 4.4% in the SB-H. While the vascular cover was correlated with increased transplant productivity which in conjunction with moisture availability (preference for hydrophilic substrate), transplant size (15cm diameter preferred over smaller colonies), and transplant location (SB-H preferred over LB-F) should all lead to decreased mortality in treatments. However, each species possesses slightly different characteristics that may be more desirable under reclamation conditions. Species that typically form hummock microform types like Sphagnum fuscum, Sphagnum magellanicum, and to some extent Sphagnum angustifolium can retain moisture under dry conditions (Clymo and Hayward, 1982; Andrus, 1986) and may be optimal for areas experiencing droughts or water limitations. Areas that are commonly inundated with water may benefit from a species that grows through lateral expansion such as Sphagnum angustifolium, Sphagnum riparium, or Sphagnum squarrosum (Andrus, 1986). With S. angustifolium possibly being the best generalist due to its ability to remain photosynthetically active throughout a large range of moisture contents, tolerate desiccation, and grow rapidly (Silvola and Aaltonen, 1984; Andrus, 1986). / Thesis / Master of Science (MSc)

The United States of America (US) has a long-standing history of fire management through the United States Forest Service. Despite this history of fire management, the US faces significant increases in fire potential across the 21st Century owing to future climate change and due to a legacy of past fuel management policies. Since the 1970s the US Forest Service (USFS) has operated a fire danger rating system, known as the National Fire Danger Rating System (NFDRS), which has aimed to portray, anticipate, and mitigate wildfires across the country. Fire danger ratings essentially aim to describe how dangerous a fire would be if it were to ignite and are used to inform not only the general public about wildfire risk but are also used by forest and fire managers to determine their actions in regards to fire suppression. The US Forest Service’s NFDRS currently produces 1-day forecasts of fire danger through the Wildland Fire Assessment System, and other state-focused outlets. The system quantifies common aspects of fire behaviour over wide spatial extents through a number of fire danger indices. These indices represent aspects of fire danger in terms of the likelihood of ignitions, rate of spread, potential heat release, and difficulty of control. Despite the NFDRS’s long-standing utility across the US, relatively few studies have sought to relate fire danger observations and forecasts to records of wildfire activity across its operational spatial extent. The majority of assessments of the NFDRS have been conducted at either single sites or on small spatial scales, despite it being a nation-wide system. This thesis analyses the NFDRS in respect to the occurrence of wildland fires and the final fire sizes they attain over an eight year period (2006-2013) through a number of analyses that; (i) examine the system’s ability to portray wildfire activity across the conterminous US; (ii) assess the NFDRS 1-day forecast’s accuracy; (iii) explore the impact of forecasting inaccuracy on wildfire activity across the conterminous US; and (iv) ascertain what outputs from the NFDRS relate most strongly to the formation of large wildfires. Firstly, this thesis shows that different regions of the US display different levels of correspondence between each observed fire danger indices and recorded fire activity. Areas in the Southern and Eastern Geographic Area Coordination Centers (GACCs) exhibit weaker correlations than those in the Northwest, Northern Rockies, Great Basin and Northern California GACCs. Peaks in fire occurrence are shown to occur at mid–low values of fire danger whereas final fire sizes increase monotonically with each fire danger index. Secondly, it is shown that the 1-day NFDRS forecasts have a strong correspondence with observed fire danger indices across the USA in the majority of locations. However, it is clear that there are multiple instances when these 1-day forecasts either over- or under-predict fire danger conditions, where there is systematic over-prediction of low-end fire danger values and under-prediction of high-end fire danger values. These predictive errors likely stem from errors in forecasted fire weather conditions, the subsequent derived fuel state and the reporting time of daily observations. Thirdly, when the inaccuracy of these forecasts was assessed spatially and temporally, the regions with the highest percentage of inaccurate forecasts were found to be in the Northern Rockies and Great Basin Geographic Area Coordination Centers (GACCs). Over-prediction was found to mainly occur between February and May, whilst peaks in the under-prediction of fire danger were found to be in spring and late summer. Finally, large wildfires appear to occur when fire danger indices are highly variable throughout the lifetime of a fire. As such this highlights the importance of considering daily variations in specific fire danger indices and that current understanding of variable fire danger conditions does not allow for the near-term prediction of large wildfire potential.