Fires are the primary method of deforestation and agricultural management in the tropics, but associated emissions such as aerosols, ozone, and carbon monoxide can have negative impacts on ecosystems, climate, and public health. Recent advances in satellite monitoring of fire activity, including using thermal anomalies for active fire detections and burn scar mapping of post-fire effects, have offered an unprecedented level of detail in understanding the magnitude and extent of fire activity. This dissertation aims to quantify the human health impact across populations in tropical regions by determining which areas are the most susceptible to transported fire emissions and how this exposure varies over time. The following chapters can be used to highlight critical conservation regions, not only for conserving ecosystems for biodiversity and climate benefits, but also for protecting public health. To address how fire emissions can affect regional populations, satellite observations of fire activity are combined with models of how tropical fire emissions are transported in the atmosphere. Satellites provide two primary pieces of information for this approach: 1) measurements of the distribution and magnitude of fire activity, and 2) categorization of fire types (such as agricultural burning or deforestation) by overlaying observed fire patterns on land use maps. Atmospheric models perform the crucial step of simulating how emissions evolve and where they are transported after release into the atmosphere. The following dissertation chapters are linked through exploration of fire emissions impacts from continental to local scales, including implementing fire emissions inventories into atmospheric models, quantifying population exposure to fire activity in Equatorial Asia, and projecting fire emissions associated with various future land use scenarios in Sumatra. Model estimates of aerosol concentrations are more influenced than trace gases by using finer temporal resolution fire emissions, due to interactions between emissions and modeled meteorology and transport. This in turn can impact air quality estimates by permitting higher peak concentrations. In addition, model results show that population exposure to fire emissions in Equatorial Asia is highly variable over time depending on the phase of the El Niño cycle; strong El Niño years can have fire contributions to fine particulate matter of up to 200 µg/m³ near fire sources, corresponding to 200 additional days per year over the World Health Organization 50 µg/m³ 24-hour fine particulate matter air quality target. These risks are not confined to people living near fire sources, but expose broad regional populations due to the atmospheric transport of emissions. Health impacts also depend on underlying fuel characteristics, with the future magnitude of Equatorial Asian fire emissions estimated to be strongly dependent on the level of protection given to fuel-rich peatswamp forests (contributing 33-48% of future emissions in the absence of protection). Collectively, these chapters emphasize variability in how tropical fire emissions affect regional population exposures to outdoor air pollution, and the need to consider the dependence of this public health effect on different fuel types and year-to-year variations in climate. The results described in this dissertation quantify direct benefits of conservation for people living near fire areas.

Chan Wing Kan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 158-173). / Abstracts in English and Chinese. / ABSTRACT --- p.i / ABSTRACT (CHINESE) --- p.iii / ACKNOWLEDGEMENTS --- p.iv / TABLE OF CONTENTS --- p.vi / LIST OF TABLES --- p.ix / LIST OF FIGURES --- p.xi / LIST OF APPENDICES --- p.xiii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- The Problems --- p.2 / Chapter 1.3 --- Conceptual Framework --- p.5 / Chapter 1.4 --- Objectives of the Study --- p.9 / Chapter 1.5 --- Significance and Scope of Study --- p.10 / Chapter 1.6 --- Organization of the Thesis --- p.11 / Chapter CHAPTER 2 --- STUDY AREAS --- p.13 / Chapter 2.1 --- Geographical Setting of Hong Kong --- p.13 / Chapter 2.1.1 --- Climate --- p.13 / Chapter 2.1.2 --- Geology --- p.15 / Chapter 2.1.3 --- Soil --- p.16 / Chapter 2.1.4 --- Vegetation --- p.16 / Chapter 2.2 --- Site Selection --- p.17 / Chapter 2.3 --- Site Description --- p.22 / Chapter 2.3.1 --- Tai Mo Shan --- p.22 / Chapter 2.3.2 --- Wu Kau Tang --- p.23 / Chapter 2.3.3 --- Tai Lam --- p.24 / Chapter CHAPTER 3 --- EFFECTS OF PARENT MATERIAL ON SOIL CHARACTERISTICS ON FIRE-AFFECTED SITES --- p.25 / Chapter 3.1 --- Introduction --- p.25 / Chapter 3.2 --- Methodology --- p.30 / Chapter 3.2.1 --- Soil Sampling --- p.30 / Chapter 3.2.2 --- Sample Preparation --- p.30 / Chapter 3.2.3 --- Soil Texture --- p.31 / Chapter 3.2.4 --- Soil Reaction --- p.31 / Chapter 3.2.5 --- Total Exchangeable Acidity --- p.31 / Chapter 3.2.6 --- Organic Carbon --- p.32 / Chapter 3.2.7 --- Total Kjeldahl Nitrogen (TKN) --- p.32 / Chapter 3.2.8 --- Mineral Nitrogen (N03-N and NH4-N) --- p.33 / Chapter 3.2.9 --- Total Phosphorus --- p.33 / Chapter 3.2.10 --- Available Phosphorus (PO4-P) --- p.34 / Chapter 3.2.11 --- "Exchangeable Cations (K, Na, Ca, Mg, Zn, Cu, Fe and Mn)" --- p.34 / Chapter 3.3 --- Data Processing and Statistical Analysis --- p.34 / Chapter 3.4 --- Results and Discussion --- p.36 / Chapter 3.4.1 --- Soil Texture --- p.36 / Chapter 3.4.2 --- Soil Reaction --- p.38 / Chapter 3.4.3 --- Total Exchangeable Acidity (TEA) --- p.42 / Chapter 3.4.4 --- Soil Organic Matter (SOM) --- p.44 / Chapter 3.4.5 --- Total Kjeldahl Nitrogen (TKN) --- p.47 / Chapter 3.4.6 --- The Carbon: Nitrogen Ratio (C: N Ratio) --- p.49 / Chapter 3.4.7 --- Mineral Nitrogen --- p.51 / Chapter 3.4.8 --- Soil Total and Available Phosphorus --- p.55 / Chapter 3.4.9 --- Soil Exchangeable Cations --- p.59 / Chapter 3.4.10 --- Effective Cation Exchange Capacity and Base Saturation --- p.67 / Chapter 3.4.11 --- Soil Trace Elements --- p.71 / Chapter 3.5 --- Conclusion --- p.77 / Chapter CHAPTER 4 --- EFFECTS OF PARENT MATERIAL ON VEGETATION DEVELOPMENT ON FIRE-AFFECTED SITES --- p.81 / Chapter 4.1 --- Introduction --- p.81 / Chapter 4.2 --- Methodology --- p.87 / Chapter 4.2.1 --- Field Survey --- p.87 / Chapter 4.2.2 --- Nomenclature --- p.87 / Chapter 4.3 --- Statistical Analysis --- p.88 / Chapter 4.3.1 --- Floristic Analysis and Indices --- p.88 / Chapter 4.3.2 --- Ordination --- p.89 / Chapter 4.3.3 --- Classification --- p.90 / Chapter 4.4 --- Results and Discussion --- p.92 / Chapter 4.4.1 --- Overall Floristic Characteristics --- p.92 / Chapter 4.4.2 --- The Effects of Parent Materials on Vegetation Communities --- p.101 / Chapter 4.4.2.1 --- Floristic Characteristics of individual site --- p.101 / Chapter 4.4.2.2 --- Ecological Indices --- p.105 / Chapter 4.4.2.3 --- Ordination (Detrended Correspondence Analysis) --- p.108 / Chapter 4.4.2.4 --- Two Way Indicator Species Analysis (TWINSPAN) --- p.114 / Chapter 4.5 --- Conclusion --- p.125 / Chapter CHAPTER 5 --- INTEGRATED DISCUSSION --- p.128 / Chapter 5.1 --- Nature of Disturbance --- p.128 / Chapter 5.2 --- Site Characteristics --- p.134 / Chapter 5.3 --- Rate of Vegetation Regeneration --- p.136 / Chapter 5.4 --- Species Selection --- p.141 / Chapter CHAPTER 6 --- CONCLUSION --- p.150 / Chapter 6.1 --- Summary of Findings --- p.150 / Chapter 6.1.1 --- Soil Properties --- p.150 / Chapter 6.1.2 --- Vegetation Regeneration --- p.153 / Chapter 6.2 --- Limitation of the Study --- p.154 / Chapter 6.3 --- Suggestion for Future Study --- p.156 / REFERENCES --- p.158 / APPENDIX --- p.174

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 33-43). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 172-187). Also available on the World Wide Web.

Forest areas are particularly susceptible to fires, which are often manmade. Too-frequent fires are likely to adversely affect the soil properties as well as vegetation composition, and possibly lead to soil erosion and desertification. One of the most fire affected forest regions in the world is the Mediterranean. Libya, in the Mediterranean region, has soils that are considered to be arid except in a small area called Aljabal Alakhdar (Green mountain), which is the geographic area covered by this study. It is the wettest part of Libya, and has an extensive forest and many agricultural crops. Like other forests in the Mediterranean it has suffered extreme degradation. This is mainly due to people removing fire wood, or sometimes converting forested areas to agricultural use, as well as fires which may alter several soil chemical and physical properties. The purpose of this research was to evaluate the effects of fires on the physical and chemical properties of soil of Aljabal Alakhdar forest in the north-east of Libya. The physical and chemical properties of soil following fire in two geographic areas have been determined, with those subjected to the fire compared to those in adjacent unburned areas in one coastal and one mountain site. Physical properties studied were: soil particle size, soil water content, soil porosity and soil particle density; and chemical properties studied were: soil electrical conductivity (EC), soil pH, soluble and exchangeable Na, K, Ca and Mg, cation exchange capacity (CEC), soluble Cl, CO3 and HCO3, SO4, organic matter, total N and total P. For the first time in Libyan soils, the effect of burning on the magnetic susceptibility properties of soils was also tested. The results showed that except for the soil water content and magnetic susceptibility, fire has not had a clear effect on the soils' physical properties, while there has been a strong impact of fire on most of the studied chemical properties. These results have been used to create an index of burning for such soils in each of the geographic areas, as a step towards creating a model which will enable a subset of soil parameters to be used to estimate how recently a site was burned, as well as defining fire severity at a site.

published_or_final_version / Applied Geosciences / Master / Master of Science

"Final report to National Park Service, Contract PX 8601-7-0106"

Giant sequoia was one of the first species that A. E. Douglass examined in his pioneering tree- ring research. Recent attention to sequoia, stimulated by fire history studies in sequoia groves, has resulted in new ring-width chronologies based on both recently collected tree-ring material and Douglass' original samples. The development and characteristics of four new multimillennial sequoia chronologies are described here. Three of these chronologies are based on tree-ring series from individual sites: Camp Six (347 B.C. to A.D. 1989), Mountain Home (1094 B.C. to A.D. 1989), and Giant Forest (1235 B.C. to A.D. 1988). The fourth is a composite chronology (1235 B.C. to A.D. 1989) that includes radii from the other three chronologies. Sequoia ring series are generally complacent with occasional narrow rings ("signature years"). Ring-width standardization was complicated by growth releases, many of which are known to have been caused by fires. Such growth releases confuse climatic interpretation of low-frequency signals in the time series. Ring- width series were detrended with cubic splines with 50% frequency response function at 40 years to de-emphasize low-frequency variation and were fit with autoregressive time series models to remove persistence. The resulting prewhitened chronologies contain primarily a high frequency climate signal and are useful for assessing the past occurrence of extreme drought events and for dating applications. The dating chronology originally developed by Douglass is confirmed and the annual nature of giant sequoia tree rings unequivocally verified.

Forest fires can have a great impact on the relationship between soil organic matter (SOM) and soilbulk density (SBD). SOM will reduce with increased fire intensity, which ultimately leads to more compaction of the soil. The compaction rate might increase to the limit of where root growth will be absent thus leading to actions to restore the soil. This study investigates changes in the relationship between SOM and SBD in spodosol and histosol in Seglingsberg, located in South-central Sweden, where a forest fire occurred summer 2014.  In addition, changes of pH values in the two types of soilwere examined in order to receive information about the chemical states of the different soil types.A total of 29 samples at depths of 0-17 cm were received from one day of fieldwork and these were later analysed concerning the pH, the SBD and the SOM content. The results showed an increase of pH-values in the fire-exposed area compared to pH values measured at the reference site (pH ~5). More importantly, the results from the SBD and SOM analyses indicated that there was in fact an inversely proportional relationship between the two soil parameters. In addition, high pH values were measured at the same subareas of which the highest SBD- and the lowest SOM values were obtained.Statistical analyses were applied on the results in order to conclude if the soil property changes caused by the fire were significantly different from normal conditions or not. The results from the statistical analyses revealed that 25% of the fire-exposed sites had changed significantly. However, more samples should have been taken while in field, since lack of data is thought to have had a great impact on the final results.Although there were no strong statistical evidence for the hypothesis, it is clear that the forest firein Västmanland year 2014 affected both the SOM, SBD and pH values in the soils. / Under sommaren år 2014 utbröt en omfattande skogsbrand i Västmanlands län, vilket medföljdedramatiska konsekvenser för framförallt ett flertal skogsbolag, men även för boende i området. Med skogsbränder följer negativa såväl som positiva konsekvenser, där de positiva framförallt gäller med avseende på arter som har evolverat i samband med bränder. Förutom ovannämnda konsekvenser så finns det risk för att markförhållandena ändras till följd av en skogsbrand. I denna studie undersöktes hur  markegenskaper  i  torv-  samt  podsoljordar  hade  förändrats  med  avseende  på  pH,  halten  avorganiskt material samt packningsgrad. Fältstudien genomfördes i ett drabbat brandområde strax norrom Seglingsberg, Surahammars kommun. Totalt togs 29 stycken jordprover inom fem stycken transekter i området. Av dessa kunde 25 stycken användas till alla tre analyserna. Resultaten från jordprovsanalyserna användes därefter till att genomföra statistiska undersökningar. Detta för att se hur stor spridningen var mellan och inom de fem transekterna samt för att kunna avgöra om jordproverna visade sig vara signifikant förändrade från ursprungsförhållanden.Resultaten från jordprovsanalyserna visade att det fanns mest organiskt material kvar i de östra delarna av området, medan det var kraftigt reducerat ju längre nordväst jordproverna hade hämtats. I samband med att markens organiska material hade reducerats kunde man även bevittna att jordtäcket hade blivit mer kompakterat. Resultaten från pH-analysen pekar också på att förändringarna varit som störst i de nordvästliga delarna. pH-analysen bevisade att markkemin ser annorlunda ut än innanbranden, då värdena ibland låg 2 enheter för högt än vad man vanligen brukar observera i podsol- ochtorvjordar. Då pH-skalan är logaritmisk innebär detta en minskad försurning med 100 gånger. Resultaten från alla jordprovsanalyser tyder att branden varit som mest intensiv i den nordvästra delen av undersökningsområdet, i området bestående av ungskog.Även om resultaten från jordprovsanalyserna pekade på att branden orsakat tydliga mark- förändringar, visade majoriteten av de statistiska undersökningarna inte på signifikanta förändringar. Det är därför inte möjligt att generalisera resultaten och således applicera dessa på hela brandområdet i Västmanland.Eftersom att naturligt förekommande skogsbränder är relativt få till antalet i Sverige, finns därmed få studier tillgängliga inom ämnesområdet. Det finns en upplaga av studier inom kontrollerade och anlagda brandfält, men i och med att dessa förhållanden är fixerade, så påverkas markegenskaperna sällan avsevärt. Forskningsrapporter indikerar på ett mer extremt klimat i framtiden, som förmodas leda till en ökad omfattning samt ett ökat antal naturligt förekommande skogsbränder. Om denna prognos stämmer är det viktigt att undersöka markförhållandena, då en skogsbrand kan ha direktavgörande effekt på återväxten.

L'Algérie fait partie des pays qui subissent un risque important en matière d'incendies de forêts, elle perd en moyenne 30 000 ha de sa couverture végétale annuellement. Ce chiffre montre, à lui seul, le niveau du risque incendie de forêt dans ce pays et suscite une inquiétude concernant les conséquences de cet aléa à plus longue échéance. Afin de cerner les enjeux environnementaux actuels et futurs, nous avons opté pour l'étude de l'effet des incendies sur les écosystèmes forestiers algériens et la mise en relief des tendances actuelles. Dans cette perspective, nous avons choisi comme objet d'étude les forêts de la Kabylie maritime (nord algérien) qui connaissent des fréquences assez élevées d'incendies et une importante vulnérabilité, depuis maintenant plusieurs années. L'étude consiste à retracer l'évolution du risque incendie dans cet espace forestier et mettre en évidence les changements morphologiques, structuraux et floraux qui y sont intervenus à travers le temps, mais aussi à analyser les changements du climat et de l'occupation de l'espace par l'homme. Ceci, afin de saisir l'influence future du changement climatique et des comportements sociaux sur l'évolution de la forêt algérienne et de tenter d'esquisser des scénarios possibles permettant d'anticiper sur des situations à risques. / Algeria is among the countries that undergo a significant risk in terms of forest fires, it loses an average of 30 000 ha of its land cover annually. This figure shows, in itself, the forest fire risk level in this country and raises a concern about the consequences of this hazard in the longer term. To identify current and future environmental issues, we decided to study the effect of fires on forest ecosystems and Algerian highlighting current trends. In this perspective, we have chosen as a case study the forests of maritime Kabylia (Algeria North) experiencing relatively high frequency of fires and a significant vulnerability for several years now. The study is to trace the evolution of the fire risk in this forest area and highlight the morphological, structural and floral changes that have occurred there over time, but also to analyze climate change and occupation space by man. This, to capture the future impact of climate change and social behavior on the evolution of the Algerian forest and attempt to outline possible scenarios to anticipate risk situations.