No description available.

Thesis (M.S.)--Baylor University, 2009. / Includes bibliographical references (p. 53-55).

Thesis (MScFor) -- Stellenbosch University, 2003. / ENGLISH ABSTRACT: Fire is a threat to all forest plantations. As a result, growers are forced to take active measures to reduce the incidence and extent of fires in their plantations. This thesis is an attempt to collate 846 fire records for eight Komatiland Forests (KLF) plantations in Mpumalanga North for the period 1950 to 1999. Up to now, these reports and the information therein, were not utilised by KLF for planning or for evaluating fire management practices. The only other studies in South Africa, using similar data, were conducted by LeRoux (1988) and Kromhout (1990). A brief background of the forestry industry in South Africa, and in particular Mpumalanga is presented. The main text of the report covers a presentation on fire causes, extent of damage (both in area and in Rand value) and various aspects related to time of ignition and response times. A detailed analysis was done to identify possible relationships between the variables related to compartment, climate and different fire suppression activities. A cause and frequency prediction model was developed that will assist fi re managers in identifying and determining probabilities of fires per cause. Statistical guidelines regarding the planning of fire management around fires caused by honey hunters, lightning, work-related factors, and the activities of people (public, own labour, contractors) are presented. Conclusions were drawn from the results of the analyses of the fire data, which covered a period of 47 years. Recommendations regarding guidelines for strategic fi re management for the Mpumalanga North plantations were made. The main conclusions are: • Statistics on previous fires are very useful in fire management planning as it supplies valuable information on fire causes, time of ignition , past performance related to response times, fire fighting times and damaged caused. • • • • The average area lost due to fires in the study area is 209.9 ha or 0.43% of the plantation area per annum. People-related fires (arson, smokers, picnickers, children and neighbours) caused most of the wild fires (48%), followed by lightning (22%). Some plantations performed poorly, with the occurrence of up to double the number of fires per 1 000 ha of plantation compared to other plantations in the same geographic area. There are definite patterns in the frequency of fires per cause with month of the year. These patterns are valuable for the development of strategies to manage fires caused by honey hunters, lightning fires and work-related fires. / AFRIKAANSE OPSOMMING: Brande is 'n bedreiging vir aile bosbou plantasies. Dit is dus noodsaaklik dat kwekers maatreeHs tref om die voorkoms en omvang van brande in plantasies te beperk. Hierdie tesis poog om 846 vuurverslae se inligting te ontleed ten opsigte van agt Komatiland Forests (KLF) plantasies in Mpumalanga Noord vir die tydperk 1950 tot 1999. Tot op hede is min van die inligting wat in die verslae vervat is deur KLF vir beplanning- en evalueringsdoeleindes ten opsigte van brandbestuur gebruik. Die enigste soortgelyke studies wat op brandverslagdata in Suid-Afrika gedoen is, is gedoen deur Le Roux (1988) en Kromhout (1990). 'n Kort agtergrond oor die bosbouindustrie in Suid-Afrika en spesifiek Mpumalanga word gegee. Die tesis gee 'n oorsig oor brandoorsake, skade wat deur brande veroorsaak word (oppervlakte sowel as finansieHe waarde) en verskeie aspekte rakende brandbestuur soos tyd van ontstaan en reaksietye. Data is volledig ontleed om moontlike verwantskappe te probeer vind tussen vak-, klimaat- en brandbestuursveranderlikes. 'n Oorsaak- en frekwensievoorspellingsmodel is ontwikkel wat brandbestuurders sal help om waarskynlikhede van brande per oorsaak te identifiseer. Statistiese riglyne ten opsigte van bestuursbeplanning vir weerligvure, brande deur heuninguithalers, brande as gevolg van plantasiewerksaamhede en ook brande deur mense (publiek, eie arbeid en kontrakteurs) is daargestel. Brandrekords wat oor 'n periode van 47 jaar gestrek het, is ontleed. Afleidings wat uit die resultate gemaak is, kan benut word om riglyne daar te stel vir strategiese brandbestuur in Mpumalanga Noord plantasies. Die hoof gevolgtrekkings is: • Statistiek van vorige vure is baie nuttig in brandbestuursbeplanning aangesien dit waardevolle inligting verskaf oor brand oorsake, tyd van ontstaan, historiese werkverrigting rakende reaksietye en blustye, sowel as skade wat veroorsaak is. Die gemiddelde oppervlakte beskadig in die studie area is 209.9 ha, of 0.43% van die plantasie oppervlakte per jaar. Menslike aktiwiteite (brandstigting, rakers, piekniekvure, kinders en vure van bure) het die meeste brande veroorsaak (48%), gevolg deur weerlig (22%). Sommige plantasies het swak gevaar en het tot soveel as dubbel die aantal vure per 1 000 ha plantasie gehad in vergelyking met ander plantasies in dieselfde geografiese gebied. Daar is duidelike patrone gevind in die frekwensie van brande per oorsaak oor maande van die jaar. Hierdie patrone is nuttig vir die ontwikkeling van bestuurstrategie vir brande wat veroorsaak word deur heuningversamelaars, weerlig en werkverwante aktiwiteite (plantasieaktiwiteite).

Understanding the quality of the air we breathe is critical in quantifying the impact that atmospheric chemistry has on health. Poor air quality increases the risk of heart and lung diseases as well as having a detrimental effect on climate, ecology and the built environment. The burning of fossil fuels and plant matter (biomass burning) creates large quantities of gases and particulate matter that impact air quality and the air we breathe. Biomass burning is estimated to contribute 400 Tg of non-methane organic compounds, 40 Tg of methane and 7.1 Tg of nitrogen oxides to the atmosphere each year. This thesis aims to better understand the role of biomass burning on air quality and tropospheric chemistry. The in depth analysis presented here addresses of the impact of boreal biomass burning in North America on air quality, in particular, carbon monoxide (CO) and ozone (O3). By using a number of different modelling techniques along with data collected from a field campaign and satellites the transport and chemistry of biomass burning emissions were analysed and quantified. The first research chapter of the thesis used the GEOS-Chem atmospheric chemistry transport model to interpret aircraft measurements of CO in biomass burning outflow taken during the 2011 BORTAS-B campaign over Canada. The model has some skill reproducing the observed variability, but has a positive bias for observations < 100 ppb and a negative bias for observations > 300 ppb. It was found that observed CO variations are largely due to fires over Ontario, with smaller and less variable contributions from fossil fuel combustion from eastern Asia and NE North America. To help interpret observed variations of CO an effective physical age of emissions (¯A) metric was developed. It was found that during BORTAS-B the age of emissions intercepted over Halifax, Nova Scotia is typically 4–11 days, and on occasion as young as two days. The analysis shows that ¯A is typically 1–5 days older than the associated photochemical ages inferred from co-located measurements of different hydrocarbons. It is argued that a robust observed relationship between CO and black carbon aerosol during BORTAS-B (r² > 0.7), form the basis of indirect evidence that aerosols co-emitted with gases during pyrolysis markedly slowed down the plume photochemistry during BORTAS-B with respect to photochemistry at the same latitude and altitude in clear skies. The second research chapter focuses on O3 production downwind from boreal biomass burning. Using the GEOS-Chem model, the O3 chemistry within a biomass burning plume from a fire on 17 July 2011 in mid-Canada was examined. The model shows a significant positive bias (~20 ppb) in reproducingO3 mixing ratios over North America for July 2011 when compared to observations. Reducing NO emissions from lightning and fossil fuel by 50% and 54% respectively reduced this bias to ~10 ppb. The cause of the remaining bias is uncertain. Using a novel technique with the model, the centre of the biomass burning plume was tracked and O3 concentrations and chemistry was extracted from the centre of the plume. The biomass burning enhanced O3 concentrations throughout the plume by between 1 – 20 ppb when compared with the same plume path with no biomass burning. The plume was characterised as being NOx-rich for the initial four days of transport. The sensitivity of the O3 chemistry to different emissions was calculated and it was found that the O3 is initially highly sensitive to NO emissions from biomass burning and then to NO emissions from fossil fuels as it travels across an urban area surrounding Quebec City. The O3 net production was found to initially decrease with an increase in NO but increase further downwind. The final research chapter of the thesis uses long-term satellite observations to evaluate natural variability in CO concentrations over the North Atlantic. 15 years of MOPITT CO column observations were used along with modelled CO from the GEOS-Chem model. The model was evaluated against the MOPITT overpass and shows a negative bias of between -8% and -24% over the northern mid-latitudes with the largest bias seen in spring. The model has a large positive bias (8% – 40%) over the Amazon,West Africa and Indonesia through all seasons. Using Empirical Orthogonal Function (EOF) analysis on the MOPITT and GEOS-Chem CO columns shows the largest mode of variability seen in the North Atlantic to be the oxidation of methane for winter and spring, biomass burning during summer and fossil fuel combustion from East Asia during autumn.

Os incêndios estão entre as principais causas da perda de diversidade em florestas tropicais e aparentemente seus impactos são ainda mais intensos em áreas de floresta sob efeito de borda. Com o objetivo de quantificar os danos causados pelo fogo sobre o ecossistema e verificar se a dimensão dos danos e a resiliência do ecossistema estão correlacionados com a distância da borda, foram analisados o banco de sementes e a comunidade vegetal em um trecho de floresta estacional semidecidual, na estação ecológica dos Caetetus, Gália, SP. A área experimental compreende dois setores: a floresta queimada, alvo de incêndio acidental e a floresta não queimada adjacente, utilizada como controle. Cada setor foi subdividido em duas faixas de distância da borda da floresta: 0-20 m e 20-50 m. Para o estudo do banco de sementes foram coletadas amostras nas quatro situações de amostragem, cinco dias após o fogo. Para avaliação dos impactos do incêndio sobre a comunidade vegetal e monitoramento da regeneração dos estratos arbóreo e regenerante na área queimada, foram amostrados cinco transectos de 10 x 50 m sentido borda - interior, avaliados aos seis, 15 e 24 meses após a passagem do fogo. O mesmo desenho amostral foi utilizado na área não queimada, em um único levantamento. Visando verificar se a eliminação de gramíneas invasoras e lianas facilitaria a regeneração da comunidade arbórea, foram instalados cinco transectos adicionais de 10 x 20 m, perpendiculares à borda, nos quais foram efetuadas quatro operações de retirada de lianas e capins, em um período de 24 meses. No banco de sementes, tanto a densidade quanto o número de espécies foram consideravelmente inferiores na área queimada (97 sementes.m-2, de 26 espécies) em comparação com a área não queimada (257 sementes.m2, de 40 espécies). A avaliação dos impactos na estrutura da floresta revelou que o fogo foi mais intenso na faixa mais externa da borda, em que houve perda de 100% da biomassa arbórea, enquanto na faixa mais interna a perda foi de 89%. Em comparação com a floresta não queimada, a comunidade vegetal na área atingida pelo fogo apresentou 43 espécies a menos aos seis meses, diferença que diminuiu para 14 espécies aos 24 meses. A resiliência, analisada com base na recuperação da biomassa arbórea, é maior na faixa mais interna, devido às espécies pioneiras oriundas de sementes que se desenvolvem rapidamente. A rebrota de árvores atingidas pelo fogo também é maior na faixa mais distante da borda e contribuiu significativamente na recuperação da riqueza. O controle de gramíneas e cipós apresentou efeito benéfico exclusivamente para o estrato arbóreo e apenas na faixa de 0-10 m de distância da borda da floresta, proporcionando aumento de área basal, densidade total de plantas e cobertura de copas. Os resultados das operações de manejo indicam que técnicas complementares devem ser aplicadas, visando à facilitação da restauração da floresta após o incêndio. O fogo mostrou-se como elemento de degradação, desde o banco de sementes até o estrato arbóreo. Ainda que a floresta tenha recuperado parte de sua riqueza em dois anos, este processo é lento, caracterizando baixa resiliência, especialmente na faixa mais externa da floresta onde o fogo é ameaça permanente. / Fire is one of the main factors causing biodiversity losses in tropical forests and such losses are reported to be still more intense in forest edges. With the aim of quantifying the damages by fire on the seasonal semideciduous forest, and verifying weather their extension and the ecosystem resilience are correlated to the border distance or not, we analyzed both the seed bank and the plant community after fire in the forest edge of Caetetus ecological station (Gália, São Paulo state, Brazil). The experimental area comprised two sectors: 1) burned area (after an incidental fire in October 2003), and 2) unburned neighboring area (control). Every sector was divided in two strips, according to the distance from the edge: 0-20 m and 20-50 m. The soil seed bank was surveyed in the four situations described, five days after fire. Plant community structure and regeneration were assessed in five permanent transections (10 x 50 m), instaled from the edge to the interior, where plant individuals were measured and identified, at six, 15, 18 and 24 months after fire. The same design was repeated once in the unburned area, for comparison. Additionally, with the aim of verifying the hypothesis that arboreal community regeneration after fire could be improved by controlling lianas and invasive grasses, five managed transections (10 x 20 m each) were installed, perpendicular to the edge, where grasses and lianas were eliminated four times within a 24 months period. Fire effects on the ecosystem were remarkable. Richness and density of the seed bank after fire (97 seeds.m-2, 26 species) were considerably lower than in the neighboring unburned forest (257 seeds.m-2, 40 species), the difference being still larger close to the edge (0-20 m). Forest structure was totally changed, 100% of the arboreal biomass lost in the external strip (0-20 m) and 89% lost in the internal strip (20-50 m). Six months after fire the burned area had 43 species, less than the unburned forest. Richness has been slowly recovered and, 24 months after fire, that difference had decreased to 14 species. Resilience, analyzed in terms of biomass recovery, is higher in the internal strip (20-50 m from the edge), where pioneer species quickly regenerate from seeds. Sprouting, which has also been more effective in the internal strip, has equally contributed to the richness recovery. Eliminating grasses and lianas favored only arboreal species in the external strip (0-10 m) where their density, basal area and crown cover were slightly higher than in the unmanaged plots. We consider that this technique, alone, can not be recommended to improve the forest restoration after fire. Fire was, though, a very strong degrading agent in the studied forest, almost completely destroying the arboreal biomass, besides the remarkable reduction in species richness in the seed bank and in the arboreal layer as well. Even though the forest richness and biodiversity have been recovered, that has been a very slow process (low resilience) specially close to the forest edge, where fire is a permanent threat.

Fire ecology encompasses the study of the factors, biotic and abiotic, that influence the occurrence of fire in an area, as well as the effects fire has on the flora and fauna native and non-native to the region (Whelan 1995). Fire has had a major influence on shaping biomes as we see them today. Fire has had an effect on vegetation much before the evolution of Homo on Earth (Keeley and Rundel 2005, Pausas and Keeley 2009, Midgley and Bond 2011). With the evolution and expansion of Homo across Earth, fire has been tamed, and then generated and used over time to yield landscapes that were suitable for their existence (Pyne 1991, Bowman et al. 2009, Archibald et al. 2012). Thus, fire, vegetation and humans were, and still are, inextricably linked in certain biomes on Earth. The best examples are observed in tropical savannas and grasslands, biomes that experience distinct seasonality in climate and are thus prone to frequent fires caused either by lightning or by humans (Keeley and Rundel 2005, Archibald et al. 2012). At the other end of the spectrum of tropical vegetation types are rainforests where the occurrence of fires is constrained by a perpetually moist environment (Meyn et al. 2007, van der Werf et al. 2008), in the absence of manipulation of the forest landscape by humans. Frequent fires have been documented to alter structure and cause a decline in forest diversity in rainforests (Cochrane and Schulze 1999, Cochrane 2003), whereas fire exclusion in mesic savannas leads to increases in biomass and transition to forest ecosystems (Bond et al. 2003, Bond et al. 2005 and references therein). A tropical biome that lies between these two extremes of vegetation types is the Seasonally Dry Tropical Forest (SDTF) where the occurrence of fire is common, but for which there are contrasting views on the effect of fire on this system (Saha and Howe 2003, Otterstrom et al. 2006 as examples). Current forest management policies in SDTF areas, especially in India, actively aim to exclude fire from these forests mostly because of the perception held by forest managers and the general public that fire has negative effects on forests. However, very few scientific studies have explored the ecology of fire in SDTFs. In order to formulate fire management policies, it is necessary to have a more comprehensive understanding of the ecology of fire in this tropical forest type. This thesis addresses two components of fire ecology as applied to SDTFs. The first is how fire is influenced by the environment, and the second, how fires influence the biotic community particular to SDTFs. The study was carried out in an SDTF in southern India where fire is a common occurrence -the forests of Mudumalai – a protected area that exhibits a range of SDTF vegetation types, from moist deciduous to dry thorn forest, corresponding to a rainfall gradient. Fire influenced by the environment: For this section, the influence of fuel load, fuel moisture and ambient weather on area burnt, fire occurrence and fire temperatures were studied in the SDTF vegetation types of Mudumalai. The extent of fire (area burnt) in an ecosystem differs according to the relative contribution of fuel load and fuel moisture available (Meyn et al. 2007). At a global scale, these factors vary along a spatial gradient of climatic conditions and are thus “varying constraints” (Krawchuk and Moritz 2011) on fire activity in natural ecosystems (Meyn et al. 2007, Krawchuk and Moritz 2011). Moist ecosystems such as tropical rainforests are at one end of the spectrum where fire activity is constrained by fuel moisture. At the other end are arid ecosystems, such as deserts, where fire activity is limited by the presence of fuels. The potential for the globally widespread seasonally dry tropical forests (SDTFs) to be placed as a single entity in this framework was examined by analyzing the interacting effects of fuel load and fuel moisture on the extent of fire in Mudumalai. Logistic regression was used to model proportion area burnt in a given year with factors that would influence fuel load and fuel moisture – these were proportion area burnt the previous year, wet season rainfall the previous year and early dry season rainfall. Modelling was conducted at two levels – the overall landscape and within four defined moisture regimes (between 700 and 1700 mm yr-1) – using a dataset of area burnt and seasonal rainfall from 1990 to 2010. The landscape scale model showed that the extent of fire in a given year within this SDTF is dependent on the combined interaction of seasonal rainfall and extent burnt the previous year. However, within individual moisture regimes the relative contribution of these factors to the annual extent burnt varied – early dry season rainfall (i.e. a moderator of fuel moisture) was the predominant factor in the wettest regime, while the previous year’s wet season rainfall (i.e. a proxy for fuel load) had a large influence on fire extent in the driest regime. Thus, the diverse structural vegetation types associated with SDTFs across a wide range of rainfall regimes would have to be examined at finer regional or local scales to understand the specific environmental drivers of fire. While the extent burnt in SDTFs is largely dependent on climatic influences, the probability of ignition has not been characterized for SDTFs. Anthropogenic fires are a regular occurrence during the dry season in SDTFs (Stott et al. 1990). We investigated if the occurrences of anthropogenic fire in Mudumalai were associated with any particular weather conditions during the dry season. Logistic regression between probability of a fire day and weather variables -seasonal rainfall, ambient relative humidity and temperature -was examined during the dry seasons of 20042010 in Mudumalai. Fire incidence data was obtained from the Fire Information for Resource Management System (FIRMS; NASA 2002) and weather data from two automatic weather stations within Mudumalai. The analysis showed that days with high probabilities of fire occurrence were associated with low levels of early dry season rainfall, low daily average relative humidity, and high daily average temperatures. These weather conditions are known to influence moisture levels of fine fuels (Viney 1991, Archibald et al. 2009). In Mudumalai as well as other SDTFs the primary fuels for fires are fine fuels such as litter and dried grass that accumulate on the forest floor during the dry season. Our results suggest that the occurrence of fire is moderated by environmental conditions that reduce or enhance the flammability of fine fuels in the dry tropics. A quantitative framework for assessing risk of a fire day has been proposed as an outcome of this analysis to assist forest managers in anticipating fire occurrences in this SDTF, and possibly for those across south Asia. Of the various components of a fire regime, fire intensity is an important aspect. High fire temperatures (one measure of fire intensity, Keeley 2009) and resulting soil temperatures would have an effect on soil properties as well as plant species demography and community structure (Moreno and Oechel 1991, Neary et al. 1999, Morrison 2002). Fires that occur frequently in a region could vary in their intensity and severity depending upon the amount of fuel available and ambient weather conditions (Stinson and Wright 1969, Stott 1986, Stronach and McNaughton 1989, Ansley et al. 1998, Wotton et al. 2012). However, this relationship has not been examined in a multiple regression framework for SDTFs. Fire temperature was recorded and its relationship with ambient weather and fuel load was studied in two SDTFs of southern India -Mudumalai and Biligiri Rangaswamy Temple (BRT) Wildlife Sanctuary in Karnataka. During “controlled burns” conducted by the forest department staff in these reserves in February and March 2010, temperature indicating lacquers on mica sheets were used to measure fire temperature at several points at ground level and one cm below the ground. Biomass was harvested close to the temperature measurement points to estimate fuel load and fuel moisture. Ambient weather conditions were recorded during the controlled burn when the flame passed over the indicators. Temperatures recorded at ground level ranged from <79oC to 760oC, with the most frequently recorded temperatures between 343-399 oC and 510566 oC. Temperatures measured one cm below the ground ranged from <79oC to 302oC, with a majority of the indicators recording temperatures in the <79oC category. Ground-level temperatures increased with increasing biomass. A linear regression of ground-level temperatures with fuel load and ambient weather conditions of relative humidity and temperature was found to explain most of the variation in the data. Ground-level fire temperatures increased with increasing fuel load, but were also found to be lower at higher relative humidities at a given temperature. In order to reduce the intensity of forest fires that occur accidentally during the dry season, we recommend that fuel loads be reduced in the forest by prescribed burning early in the dry season. This applies especially to areas where there is accumulation of biomass over years, such as that of the tall grass Themeda cymbaria found predominantly in dry deciduous forest types. If prescribed burning is incorporated in fire management policies for these forests, then the season of burning will be important to consider. It is known from ecosystems where prescribed burning is regularly applied that early dry season fires are less intense than late dry season fires (Williams et al. 1998). However, this has not been systematically investigated for SDTFs. Through a burning experiment carried out in private land with vegetation type similar to tropical dry thorn forest, we investigated differences in area burnt, ground-level fire temperatures and soil temperatures one cm below the ground in the early dry season in January, late dry season in April and and early wet season in June. We also examined differences in fuel load, fuel moisture, soil moisture and weather conditions of ambient relative humidity (RH), temperature and wind speed in these phases; these factors could be responsible for observed differences in fire and soil temperatures or area burnt. Although area burnt was not significantly different between the early and late phases of the dry season, fire and soil temperatures were significantly lower in the former. The late dry season was characterized by distinctly higher fuel loads, lower fuel moisture, lower relative humidity, higher ambient temperatures and higher wind speeds compared that measured in the early dry season. Differences in soil temperature between these months may be attributed to the increase in fuel load since there were no significant differences in soil moisture. Fire spread was limited in the experimental plots in the early wet season in June, probably due to significantly higher levels of fuel moisture in this month; the resultant fire and soil temperatures recorded were low. Forest management should, therefore, consider early dry season burns in the month of January for prescribed burns in the sanctuary, although this would have to be tested in other SDTF vegetation types with more variable fuel load, fuel moisture and weather conditions. Fire’s influence on the biotic community: Concerns regarding the regeneration capacity of woody species in SDTFs have been voiced with respect to increasing frequencies of fire (Saha and Howe 2006, Kodandapani et al. 2008). Fire is known to cause high mortality of individuals of small size (Swaine et al. 1990, Suresh et al. 2010). However, mortality has been examined for large size classes, and not for seedlings. It is essential to understand the dynamics of seedlings and their contribution to the regeneration potential of SDTFs. Woody species in SDTFs are known to have traits that help them recover from recurring disturbances, such as sprouting from underground root stocks (Vieira and Scariot 2006). Another trait may relate to growth rates of seedlings. Growth rates of seedlings (defined in this study as established individuals between 10 and 100cm height) after dry season (February-March) fires were compared between adjacent pairs of burnt and unburnt transects established at eight sites in Mudumalai across vegetation types of moist deciduous, dry deciduous and dry thorn forest. The growth of grasses, a possible competitor for resources, was also monitored at each site. Seedling and grass heights were monitored at 3-month intervals between August 2009 and August 2010. A second fire in March 2010 affected transects at two sites in Mudumalai. Seedling and grass heights were monitored for two enumerations till August 2010 subsequent to the second fire at these two sites. A total of 1032 individuals across 58 woody species were enumerated. High seedling survivorship (>95%) was observed in both burnt and unburnt areas. Although seedling heights were significantly different between burnt and unburnt areas at the start of the enumeration in August 2009, heights were comparable within a year and a half of the fire. Comparable seedling heights in such a short time span were because of distinctly higher growth rates of seedlings in burnt areas compared to unburnt areas after the fire event, particularly during the pre-monsoon season. Grass biomass (volume), on the other hand, was significantly different between burnt and unburnt areas at both the first and last enumerations. Grass growth (change in volume) did not differ between burnt and unburnt areas. Rapid growth by seedlings after a fire implies adaptation through the use of stored resources for growth, possibly aided by lower competition from grasses, in order to attain a certain size before the subsequent return of unfavourable factors such as a recurrent fire event. Conclusions: The results from the study point to climatically driven fire regimes in an SDTF in southern India, with daily influences of weather conditions during the dry season on fire occurrences. Fire intensities increase with increasing fuel loads in these forests, moderated by weather conditions such as RH and temperature. Since fires are an anthropogenic phenomenon in these forests, active management with the use of prescribed fires in the early phase of the dry season is a possible option to control late dry season fires that would be higher in intensity. The current woody tree species assemblage in this southern Indian SDTF is resilient to fires at the seedling stage, with established individuals exhibiting high survivorship and rapid growth after a fire. However, the effects of fires of varying intensities on the regenerative capacity of the seedlings are not known. The effect of fire on habitat utilisation by large herbivores, or the impact of fire on the faunal community in general has not been studied for vegetation types that comprise SDTFs. The effect of fire exclusion on the ecology of SDTFs will provide useful information that can feed into management policies for this ecosystem type. These are potential areas of research for the future. Fire, if managed wisely, can be an effective tool for the conservation of SDTFs across south and southeast Asia.

No description available.

Forest fires cause a significant amount of damage and destruction each year. Optimally dispatching resources reduces the amount of damage a forest fire can cause. Models predict the fire spread to provide the data required to optimally dispatch resources. However, the models are only as accurate as the data used to build them. Satellites are one valuable tool in the collection of data for the forest fire models. Satellites provide data on the types of vegetation, the wind speed and direction, the soil moisture content, etc. The current operating paradigm is to passively collect data when possible. However, images from directly overhead provide better resolution and are easier to process. Maneuvering a constellation of satellites to fly directly over the forest fire provides higher quality data than is achieved with the current operating paradigm. Before launch, the location of the forest fire is unknown. Therefore, it is impossible to optimize the initial orbits for the satellites. Instead, the expected cost of maneuvering to observe the forest fire determines the optimal initial orbits. A two-stage stochastic programming approach is well suited for this class of problem where initial decisions are made with an uncertain future and then subsequent decisions are made once a scenario is realized. A repeat ground track orbit provides a non-maneuvering, natural solution providing a daily flyover of the forest fire. However, additional maneuvers provide a second daily flyover of the forest fire. The additional maneuvering comes at a significant cost in terms of additional fuel, but provides more data collection opportunities. After data are collected, ground stations receive the data for processing. Optimally selecting the ground station locations reduce the number of built ground stations and reduces the data fusion issues. However, the location of the forest fire alters the optimal ground station sites. A two-stage stochastic programming approach optimizes the selection of ground stations to maximize the expected amount of data downloaded from a satellite. The approaches of selecting initial orbits and ground station locations including uncertainty will provide a robust system to reduce the amount of damage caused by forest fires.

Every year wildfires threaten or destroy ecological habitats, man-made infrastructure and people’s lives. Additionally millions of dollars are spent each year trying to prevent and control these fires. Ideally if a wildfire can be detected before it rages out of control it can be extinguished and avoid large scale devastation. Traditional manned fire lookout towers are neither cost effective nor particularly efficient at detecting wildfire. It is proposed that temporal filtering can be used to isolate the signals created at the beginnings of potential wildfires. Temporal filtering can remove any background image and any periodic signals created by the camera movement. Once typical signals are analyzed, digital filters can be designed to pass fire signals while blocking the unwanted signals. The temporal filter passes only fire signals and signals generated by moving objects. These objects can be distinguished from each other by analyzing the objects mid and long wave energy profile. This algorithm is tested on 17 data sources and its results analyzed.

No description available.