Effects of herbivory, fire, and tree harvesting on Acacia drepanolobium were studied using plant population dynamics as the philosophical basis of research. Specifically, growth rates, chrono-sequence of re-growth, biomass and charcoal yield, herbivory, flowering, seed production, germination, mortality and the ants of Acacia drepanolobium were studied in the black cotton ecosystem of Mpala Research Centre, Laikipia, Kenya, between September 1995 and December 2000. Acacia drepanolobium was the most abundant tree or shrub with densities ranging from 80% to 98% of all the overstorey species, but it was the least browsed of all the trees and shrubs in the black cotton ecosystem, ranging from a mean of 7.2% to 9% of the individuals browsed. The tree is inhabited by four Acacia ant species, Crematogaster mimosae, Crematogaster sjoestedti, Crematogaster nigriceps, and Tetraponera penzigi, which are believed to be obligate, and which probably play a role in the low browsing rates observed. Six herbivore treatments replicated three times (no herbivores - O; only cattle - C, all herbivores allowed - MWC {control}, mega-herbivores {elephants and giraffe} and wildlife {W} – MW only, wildlife – W - only {all wildlife except mega-herbivores} and wildlife and cattle only - WC) was the main experimental design used in understanding the dynamics of the tree species under influence of different herbivores. Mean annual height growth of A. drepanolobium trees was 24.9 cm yr-1, while the mean Relative Growth Rates ranged from 14.6 x 10 –3 cm cm-1 yr-1 to 18.7 x 10 –3 cm cm-1 yr-1. Growth rates were different among the herbivore treatments and between seasons. Shoots of the tree grew by a mean range of 6.8 cm to 9.1 cm, were similar among the treatments but differed among the seasons. Canopy volume increased over time although it fluctuated with seasons, suggesting an increase in bushiness of A. drepanolobium in the ecosystem. Trees occupied by different ant species showed differences in shoot density (number of new shoots per twig), being greater in Crematogaster nigriceps occupied trees compared with the other ant species. Swollen thorn (gall) density per unit of twig length was greatest in treatments with megaherbivores; these galls were significantly larger on trees occupied by the ant Crematogaster nigriceps. Treatments with herbivores were more spinescent than the total exclusion treatment. Spine lengths ranged from 0.8 to 2.4 cm, and recorded a progressive reduction of up to 36.36.7% in treatments without browsers suggesting a relaxation of induced defence in A. drepanolobium. Flowering in A. drepanolobium was low and staggered over the study period ranging from 0.8% to 2.0% of the trees with no differences among the treatments suggesting that the level of herbivory was not sufficient to influence reproduction of the tree in the experimental site. Consequently, seedling recruitment was very low within the experimental site. However, a nearby site recorded flowering of between 22.7% and 93.5%. Mean pod production, mean number of seeds per tree and mean weight of pods and seeds had a positive linear relationship with tree density (R2=0.77, 0.81 and 0.81 respectively). Trees occupied by Crematogaster mimosae were the most likely to flower (68%) compared with C. nigriceps (5.8%), again suggesting that ants had an effect on the tree’s reproduction. Mortality of A. drepanolobium trees averaged 0.9% to 4.2% over the study period, being significantly greater in treatments with mega-herbivores. Seedling survival ranged from 42% to 75%, being greatest in the cattle only treatment. Between 30% and 100% (mean 67.2%), of A. drepanolobium seeds were attacked by a bruchid beetle (Bruchus sp.). Seeds attacked by bruchid beetles had significantly lower germination rates. Similarly, seeds passed through a fire also recoded significantly low germination rates compared with normal seeds. Fire (3.4%) and bruchid beetles (20.7%) germination compared with (control) undamaged seeds (84%) play an important role in the population dynamics of A. drepanolobium. Fewer A. drepanolobium seeds (33%) were recovered from the surface compared with buried (72%) seeds after a fire, indicating seed loss from the effect of fire and predation. In the burn experiment, fire top-killed 16% of A. drepanolobium trees but no tree or seedling was killed. On the other hand, fire significantly reduced the density of non-A. drepanolobium trees by between 50% and 100%, with none of them showing signs of coppicing after the fire unlike top-killed A. drepanolobium trees. Woody biomass from A. drepanolobium was strongly related to stem diameter (Y = 3.77x + 1.17, R2 = 0.96, P < 0.001). Mean charcoal production from earthen kilns was 2.83 Mg ha- 1. Height and stem diameter in coppicing stands increased at a mean rate of 28.6 cm yr-1 and 0.7 cm yr-1 respectively. Biomass in coppicing stands accumulated at a mean rate of 1.3 Mg ha-1 yr-1 in a 14-year period, yielding dry biomass of 18.26 Mg ha-1 useable wood that can produce a minimum of 3.0 Mg ha-1 of charcoal. This study shows that Acacia drepanolobium populations are affected by several factors including herbivory, fire and ants. The population dynamics of this tree shows that it can be harvested for sustainable charcoal yield over a 14-year cycle. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

Each year many forest fires have occurred and huge amount of forest areas in each country have been lost. Turkey like many world countries have forest fire problem. 27 % of Turkey&amp / #65533 / s lands are covered by forest and 48 % of these forest areas are productive, however 52 % of them must be protected. There occurred 21000 forest fires due to several reasons between 1993 and 2002. It is estimated that 23477 ha area has been destroyed annually due to wildfires. The fire management strategies can be built on the scenarios derived from the simulation processes. In this study a GIS &amp / #65533 / based fire simulating model is used to simulate a past fire occurred in Marmaris &amp / #65533 / &Ccedil / etibeli, Turkey, in August 2002. This model uses Rothermel&amp / #65533 / s surface fire model, Rothermel&amp / #65533 / s and Van Wagner&amp / #65533 / s crown fire model and Albini&amp / #65533 / s torching tree model. The input variables required by the model can be divided into four groups: fuel type, fuel moisture, topography and wind. The suitable fuel type classification of the vegetation of the study area has been performed according to the Northern Forest Fire Laboratory (NFFL) Fuel Model. The fuel moisture data were obtained from the experts working in the General Directorate of Forestry. The fire spread pattern was derived using two IKONOS images representing the pre- and post-fire situations by visual interpretation. Time of arrival, the rate of spread and the spread direction of the fire were obtained as the output and 70 % of the burned area was estimated correctly from the fire simulating model.

Thesis (MSc (Geography and Environmental Studies))--University of Stellenbosch, 2006. / A multitude of unique fauna and flora exist within the Western Cape of South Africa. Fire plays an intricate role in the conservation and extinction of many of these species. It is therefore imperative to understand this delicate relationship in order to help preserve the province’s uniquely balanced ecosystem. The Western Cape Nature Conservation Board (WCNCB) expressed the need for a system that would allow reserve managers to produce basic fire frequency and veld age maps with considerable ease. These maps are needed for intelligent decisionmaking regarding the management of veldfires. Information concerning vegetation and historical veldfires in the Western Cape, collected over a period of 50 years exist in tabular format in databases of the WCNCB. Some of these tables contain spatial information elements, such as areas affected by fires. Tabular data with spatial elements can be converted to a geographical information system (GIS) format, extracting value previously shielded from the user. Using GIS techniques and the programming language Avenue, two tools with powerful decision-making qualities were created to extract value from these datasets. One tool shows the fire history of a specified area as a digital map. This map shows areas with varying occurrences of fires over time, thereby highlighting hot spots within the specified location. The ability to view various fire scar datasets spatially over a specified period, as opposed to records in a table, enables the user to understand the extent to which areas have been repeatedly exposed to fire and quickly identify areas most affected. The second tool shows vegetation age in a similar fashion, allowing the user to see the current spatial distribution of vegetation and its age. Knowledge about the age of indigenous vegetation, such as fynbos, in a predetermined area, facilitates the reserve manager in decisions related to block burning. This is an accepted practise in areas where vegetation requires fire to stimulate germination. Both tools provide decisionmaking support to reserve managers regarding the most suitable course of action in terms of the implementation of a proactive or passive approach towards fires. This study satisfies the needs of the WCNCB by exploring the hidden value within their datasets. GIS supported by the programming language, Avenue, was successfully utilised in the development of a system capable of extracting information from current datasets to support reserve managers in their critical decision-making processes.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Current efforts to address Zimbabwe‘s decade long veld fire crisis has partly been hindered by a lack of financial resources and fire data. This study illustrates the potential of using the MODIS burned area product as an alternative cost- and time-effective method for reconstructing historical fire records in Zimbabwe. Two MODIS burned area products were evaluated, namely the MCD45A1 and WAMIS (Meraka Institute‘s MODIS burned area product). Both products yielded similar levels of accuracy despite the difference in algorithms. However, it is assumed that at certain thresholds, either in tree cover or fire intensity, WAMIS ceases to map fires as accurately as the MCD45A1. Ten years of fire data for Charara Safari Area (CSA) was extracted from the MCD45A1, and used as a basis to establish six parameters: fire incidence, extent, seasonality, fire size, frequency and fire return interval (FRI). It was observed that approximately 50% of CSA burned annually, with an average of 132 fires occurring every year. Although there was no overall increase or decrease in the extent of area burned over the 10 year study period, an increasing trend in fire incidence was noted. Through an assessment of effective fire size, it was established that more fires in CSA were gradually becoming smaller in size, while the extent of area burned remained fairly constant. Hence, the increase in fire incidences and lack of a corresponding increase in area burned. This study was also used to identify areas in the fire regime that may be a potential ecological risk to the miombo woodland in CSA. Three points of concern were revealed: firstly, a high prevalence of late season fires was observed in the northern bounds of CSA. Secondly, 64.2% of the total area burned in CSA burned between 6 and 10 times over the 10 year period, and lastly, 85% of the total area burned over the period 2001 and 2010 had a FRI of less than 2 years. The combination of late season fires, high fire frequency and short FRI in CSA is indicative of possible alterations in the state of the miombo woodlands, which may have negative socio-economic implications on CSA and its surrounding communities. This study has demonstrated that the MCD45A1 is a useful source of much needed fire information for Zimbabwe. Therefore, the possibility of integrating methods employed in this study into the current collection of fire data should be given due consideration. / AFRIKAANSE OPSOMMING: Huidige pogings om Zimbabwe se dekade lank veldbrand krisis aan te spreek is gedeeltelik belemmer deur 'n gebrek aan finansiële hulpbronne en vuurdata. Hierdie studie illustreer die potensiaal van die gebruik van die MODIS verbrande area produk as 'n alternatiewe koste-en tyd-effektiewe metode vir die rekonstruksie van historiese vuurrekords in Zimbabwe. Twee MODIS verbrande area produkte is geëvalueer, naamlik die MCD45A1 en WAMIS (Meraka Instituut se MODIS verbrand area produk). Beide produkte het soortgelyke vlakke van akkuraatheid opgelewer ten spyte van die verskil in die algoritmes. Dit word egter aanvaar dat op sekere drempels, óf in die boom bedekking, of brandintensiteit, WAMIS brande minder akkuraat karteer as die MCD45A1 produk. Tien jaar van vuurdata vir Charara Safari Area (CSA) is uit die MCD45A1 data onttrek, en gebruik as 'n basis om ses parameters vas te stel: vuurvoorkoms, omvang, seisoenaliteit, vuurgrootte, frekwensie en tyd tussen die terugkeer van vuur na ‗n spesifieke plek (nl. FRI). Dit is waargeneem dat ongeveer 50% van die CSA jaarliks gebrand word, met 'n gemiddeld van 132 brande wat elke jaar voorkom. Daar was nie 'n algehele toename of afname in die omvang van die totale verbrande area oor die 10 jaar studietydperk nie. Maar 'n toenemende neiging in die vuurvoorkoms was wel opgemerk. Deur middel van 'n assessering van effektiewe vuurgrootte, is daar vasgestel dat meer kleiner brande in CSA voorkom, terwyl die omvang van die verbrand area redelik konstant gebly het. Dus was daar ‗n toename in die aantal vuurvoorvalle al was daar nie 'n ooreenstemmende toename in die totale verbrande oppervlakte was nie. Hierdie studie is ook gebruik om gebiede in die vuurregime te identifiseer wat 'n potensiële ekologiese risiko vir die miombobosveld in CSA inhou. Drie punte van kommer word geopenbaar: eerstens, 'n hoë voorkoms van laatseisoen brande is waargeneem in die noordelike grense van CSA. Tweedens, 64,2% van die totale verbrande oppervlakte in die CSA brand tussen 6 en 10 keer bine die 10-jaar periode. Laastens, 85% van die totale verbrande oppervlakte oor die tydperk 2001 tot 2010 het 'n FRI van minder as twee jaar. Die kombinasie van laatseisoen brande, hoë vuurfrekwensie en kort FRI in CSA is 'n aanduiding van moontlike veranderinge in die toestand van die miomboveld, wat negatiewe sosio-ekonomiese implikasies op die CSA en die omliggende gemeenskappe kan uitoefen. Hierdie studie het getoon dat die MCD45A1 'n nuttige bron van broodnodige vuur inligting vir Zimbabwe is. Daarom, moet die moontlikheid van die integrasie van die metodes wat gebruik word in hierdie studie in die huidige versameling van vuurdata behoorlike oorweging gegee word.

Fire is generally used as a management tool for different vegetation types such as savannas and grasslands in southern Africa. In the False Thornveld of the Eastern Cape, fire is commonly used to control bush encroachment and to increase grass production, as grasses are important source of forage for domestic livestock. At the University of Fort Hare farm in the Eastern Cape, a trial was set up in 1980 to investigate the effect of burning frequency on vegetation. There are six treatments replicated twice in a completely randomized design on a 100 m x 50 m plots. The treatments comprise no burn, annual, biennial, triennial, quadrennial and sexennial burns. From this trial a study was conducted to investigate long term effect of burning frequency on species and soil seed bank diversity. Two 100 m line transects located 25 m apart were laid within each plot, and the herbaceous and woody species were identified and recorded along the line transects. Relative abundances (%) for each species were calculated for each treatment. Soil samples were collected at an interval of 13.3 m along the line transects. The samples were placed in paper bags and kept for use in a germination experiment. The seedling emergence germination method was used in the glasshouse to determine emerging seedlings, pots were filled with Hygromix growth medium and the soils from the fire trials 12 X 6 = 72 were spread on top. Soil from the control plots were also pre-treated with heat, smoke and the combination of heat and smoke. The experiment started in January 2010 and was terminated in April 2010. The Shannon-Weaver Diversity Index was used to determine species diversity for standing vegetation and germinated seedlings. Data were tested for normality and species abundances were transformed. Analysis of Variance (ANOVA) was applied to test treatment effects on geminated seedlings, species abundance and diversity at α = 0.05 significance level. Significant differences between treatment means were determined by post v hoc tests using Fischer‟s Least Significant Difference test at α = 0.05. The Pearson Moment Correlation test was used to test the relationship between vegetation and soil seed banks. Treatments had significant effects on herbaceous, woody species abundance and diversity (P < 0.05), but there was no significant treatment effect on soil seed bank diversity and on pre-germination treatments (P > 0.05). The annual, biennial and triennial burns were dominated by Themeda triandra while the quadrennial, sexennial and the control treatments were dominated by Sporobolus fimbriatus and Melica decumbens. A. karroo dominated the woody component across all treatments, but it did not change in abundance. S. fimbriatus was the most abundant in the soil seed bank across all the treatments and also in all pre-germination treatments. Species diversity was high in standing vegetation in the quadrennial, sexennial and the control treatments. There was no significant correlation between the standing vegetation and soil seed bank diversities (P > 0.05). Based on these findings it is apparent that fire can change vegetation in an area to be dominated by fire tolerant or fire intolerant species. Fire frequency, heat and smoke affects soil seed banks to a lesser extent in the False Thornveld. For the management of the False Thornveld of the Eastern Cape, less frequent burning is recommended as it increases aboveground species diversity.

Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-07-06T13:25:22Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) thais_ribeiro_costa.pdf: 3235496 bytes, checksum: 6f8cdc08809043df5efea75372782e92 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-07-18T13:13:10Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) thais_ribeiro_costa.pdf: 3235496 bytes, checksum: 6f8cdc08809043df5efea75372782e92 (MD5) / Made available in DSpace on 2018-07-18T13:13:10Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) thais_ribeiro_costa.pdf: 3235496 bytes, checksum: 6f8cdc08809043df5efea75372782e92 (MD5) Previous issue date: 2017 / Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Este estudo teve como objetivo conhecer a composi??o flor?stica da comunidade arb?rea e sua rela??o com o ambiente, bem como avaliar a diversidade, estrutura e as fun??es ecol?gicas das esp?cies de dezoito fragmentos de mata de galeria inund?vel. Al?m disso, se prop?s a caracterizar a vegeta??o da matriz de entorno de nove fragmentos de mata e galeria, bem como verificar se vari?veis ambientais atuam na transi??o entre as duas fitofisionomias, com ?nfase nas propriedades qu?micas do solo. O estudo foi conduzido no Parque Nacional das Sempre-Vivas, na Serra do Espinha?o, Minas Gerais. Foram inventariadas 5% da ?rea total de cada fragmento, instalando-se parcelas permanentes de 100 m? (totalizando 0,72 ha de amostragem), onde foram amostrados todos os indiv?duos arb?reos com di?metro ? altura do peito igual ou superior a 5 cm (DAP ? 5 cm). Para amostragem da cobertura vegetacional da matriz de entorno, foi utilizado o m?todo dos pontos, totalizando 12 pontos por fragmento, distribu?dos nas dist?ncias de 10, 20 e 30 m no sentido borda-campo. Em cada parcela e em cada ponto, foi mensurada a umidade do solo e coletadas amostras de solo, para posteriores an?lises qu?micas. Para os fragmentos foram mensurados qualitivamente a cobertura do dossel, altura de crestamento e impactos ambientais. Foram amostrados 1265 indiv?duos arb?reos, distribu?dos em 76 esp?cies, 55 g?neros e 32 fam?lias. A comunidade em geral, apresentou valores de diversidade e equabilidade compativeis com outras matas de galeria inund?veis do pa?s. As esp?cies amostradas foram agrupadas em seis grupos funcionais distintos. A maioria dos fragmentos apresentou uma tend?ncia de est?gio seral mais avan?ado, com esp?cies predominantemente secund?rias iniciais e tardias, zooc?ricas, zoo?filas, densidade m?dia da madeira, sementes recalcitrantes e pl?ntulas do tipo faneroep?geo-foli?ceo. A distribui??o por classes diam?tricas dos indiv?duos da comunidade arb?rea e para as principais popula??es obteve uma tend?ncia de J-invertido, indicando bom potencial regenerativo. As vari?veis ambientais que se correlacionaram com a varia??o da composi??o de esp?cies foram ? disponibilidade de ?gua e condi??es de acidez. O baixo percentual de explica??o das vari?veis ambientais e espaciais ressaltam que as esp?cies nos fragmentos de mata de galeria distribuem-se de maneira estoc?stica. O fogo constituiu o impacto mais frequente no interior dos fragmentos, o que ressalta a necessidade de t?cnicas de manejo nessas ?reas. Os campos ?midos ao entorno dos fragmentos apresentaram-se com elevada cobertura de herb?ceas, mesmo ap?s o manejo do fogo. Para as caracter?sticas ed?ficas avaliadas observaram-se os maiores valores de umidade, pot?ssio, soma de bases, capacidade de troca cati?nica total e mat?ria org?nica nos solos sob floresta. Portanto, a defini??o dos limites entre as duas fitocenoses estudadas parece ser primariamente relacionada com o gradiente de fertilidade e umidade do solo. Permite-se aqui chamar a aten??o para a import?ncia de estudos de pequenos fragmentos vegetacionais para a amplia??o do conhecimento sobre a diversidade ambiental local e regional, e seus principais determinantes, e poss?veis consequ?ncias para a din?mica da vegeta??o dos ecossistemas. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / This study aimed to know the floristic composition of the tree community and its relationship with the environment, as well as to evaluate the diversity, structure and ecological functions of the species of eighteen fragments of forest of flooded gallery. In addition, it was proposed to characterize the vegetation of the surrounding matrix of nine forest fragments and gallery, as well as to verify if environmental variables act in the transition between the two phytophysiognomies, with emphasis on the chemical properties of the soil. The study was conducted in the Sempre-Vivas National Park, in the Serra do Espinha?o, Minas Gerais. 5% of the total area of each fragment were inventoried, and permanent plots of 100 m? (totaling 0.72 ha of sampling) were sampled, where all arboreal individuals with a breast height diameter equal to or greater than 5 cm were sampled (DAP ? 5 cm). In order to sample the vegetative cover of the environment matrix, the points method was used, totaling 12 points per fragment, distributed at distances of 10, 20 and 30 m in the edge-field direction. In each plot and at each point, soil moisture was measured and soil samples were collected for further chemical analysis. For the fragments, the canopy cover, height of crust and environmental impacts were measured. A total of 1265 arboreal individuals were sampled, distributed in 76 species, 55 genera and 32 families. The community in general presented values of diversity and equability compatible with other floodplain gallery forests in the country. The species sampled were grouped into six distinct functional groups. Most of the fragments presented a trend of more advanced seral stage, with predominantly early and late secondary species, zoocoric, zoo-philological, mean wood density, recalcitrant seeds, and phaneroege-foliaceous-type seedlings. The distribution by diameter classes of the individuals of the tree community and for the main populations obtained a tendency of J-inverted, indicating good regenerative potential. The environmental variables that correlated with the variation of the species composition were the availability of water and acidity conditions. The low percentage of explanation of the environmental and spatial variables emphasize that the species in the fragments of gallery forest distribute stochastic way. Fire was the most frequent impact within the fragments, which highlights the need for management techniques in these areas. The wetlands surrounding the fragments presented high herbaceous cover, even after fire management. The highest values of moisture, potassium, sum of bases, total cation exchange capacity and organic matter in soils under forest were observed for edaphic characteristics evaluated. Therefore, the definition of the boundaries between the two phytochenoses studied seems to be primarily related to the fertility and soil moisture gradients. It is worth noting here the importance of studies of small vegetation fragments to increase knowledge about local and regional environmental diversity and their main determinants and possible consequences for the dynamics of ecosystem vegetation.

While wildfire is globally most common in the savanna-grassland ecotone, the flammability of coastal temperate rainforests is considered low and little is known regarding historic fire activity. Reconstructing historical fire activity typically requires dendrochronological records from fire-scarred trees and post-fire cohorts, but this type of information is rare in perhumid temperate rainforests, which are dominated by dense fuels with high year-round moisture content. I reconstructed historic fire activity using fire scars, tree rings, soil charcoal, and remote sensing techniques in a 2000 km2 island group located within the Hakai Lúxvbálís Conservancy on the coastal margin of central British Columbia. I broadly assessed 13,000 years of fire activity with charcoal deposited in soils, and reconstructed late Holocene fire events with a 700-year chronology built from living fire-scarred trees and stand establishment data. I used a weight of evidence approach to hypothesize the origins of fires and whether First Nations intentionally utilized fire for resource management. Low-severity fires occurred most frequently in forests surrounding former First Nations habitation sites, and lightning strikes do not occur often enough to explain the observed temporal or spatial patterns of fire activity in the study area. Low-severity fires occurred approximately every 39 years, and were 25 times more likely to occur than previously estimated. Fires influenced the composition and structure of vegetation by creating a mosaic of vegetation types in different stages of succession, and thus increased the abundance of culturally important food plants. Fire events have not occurred in the study area since 1893, which also coincides with the reduction of First Nations activities in their traditional territories. My data are consistent with the hypothesis that humans intentionally used fire to manage resources, though further research and ethnographic data collected elsewhere in the region is required to corroborate these findings. Ecological legacies of historic fires remain visible on the present day landscape, and by reconstructing the historic range of fire cycle variability we gain a better understanding of human-driven fire activity and the abrupt changes that occurred in the 20th century. / Graduate

<p>  </p> <p>Alterations to the historic fire regime have contributed to widespread regeneration failure in <em>Quercus</em> L. (oak) forests of the eastern United States. Composition has shifted from <em>Quercus</em> and other fire-adapted species to dominance by mesophytic species. While land managers often focus efforts on restoring <em>Quercus</em> regeneration, the herbaceous layer experiences reduced cover and diversity of herb and graminoid species resulting from the increased woody stem density in fire-suppressed forests. Declining abundance of <em>Quercus</em> species and diversity in the herbaceous layer reduce the overall habitat quality and ecosystem functions provided by the forest. A combination of overstory harvests and prescribed burning are often conducted to restore the plant community in <em>Quercus</em> forests affected by mesophication. Initiated in 2010, our study on the Hoosier National Forest in Indiana conducted shelterwood and midstory (mechanical, chemical, or none) harvests followed by prescribed burning on a less productive site, while leaving a more productive site unburned. Our objective was to evaluate the survival and competitive response of <em>Quercus</em> spp. within the regeneration layer and whether diversity and cover increased in the herbaceous layer following treatments. Using nested circular plots, we measured seedling survival and resprout response, in addition to regeneration density before and after treatments. We measured the percent cover of herbaceous-layer species within quadrats and calculated species richness, evenness, and diversity. Using multiple mixed-effects models, ANOVA, and NMDS ordination, we evaluated woody species regeneration and herbaceous-layer composition before and after treatments. Post-treatment, monitored <em>Quercus</em> spp. seedlings at the burned site displayed greater survival (> 94%) and resprouting (> 92% of monitored stems), which exceeded most competing species, including<em> Acer</em> spp. (~ 59% survival and resprouting) and <em>Fraxinus americana </em>(72% survival and resprouting). <em>Q. alba</em> seedling (< 3.8 cm DBH) densities doubled after burning; it was one of the most abundant species (9,864 stems ha-1) at the burned site. NMDS ordination indicated a clear shift in regeneration species composition with the burn driving a shift away from mesophytic species towards greater importance of <em>Quercus</em> species. Additionally, our burned site had significantly increased herbaceous-layer richness, Shannon diversity index, and total cover compared to pre-treatment. Percent cover increased across all plant functional groups within the herbaceous layer, with trees/shrubs exhibiting the greatest increase. Herbaceous-layer composition at the burned site significantly shifted toward greater importance of graminoids and herbs post-treatment. Post-treatment, the unburned site contained fewer, and less competitive, <em>Quercus</em> seedlings compared to non-<em>Quercus</em> competitors and displayed no significant compositional shifts in seedling species composition post-harvest. Our unburned site exhibited significant, but minor, increases in herbaceous-layer richness, evenness, diversity, and total cover. Herbaceous-layer composition at the unburned site was significantly different post-treatment, shifting towards greater importance of vines, trees/shrubs, and herbs. The more-productive unburned site would likely require multiple burns to produce adequate competitive <em>Quercus</em> seedlings to perpetuate dominance in the developing stand. Burning would also likely result in greater increases in herbaceous-layer diversity compared to harvesting alone. Conversely, the shelterwood, followed by a single burn, on the less productive site had a more substantial effect on the herbaceous layer, and likely produced an adequate density of <em>Quercus</em> reproduction to ensure future dominance by the genus.</p>

No description available.

Thesis (MPhil (Sociology and Social Anthropology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: This study examines the issue of informal settlement fires, specifically in Kayamandi a township of Stellenbosch in the Western Cape province of South Africa. The study aims to identify the relevant role-players involved in addressing the issue and to understand the unique dynamics involved in this type of fires at the local level context. The study illuminates the main contextual factors that contribute to the perpetuation of informal settlement sprawl in South Africa and that relates to the risk and vulnerability experienced by informal settlement dwellers. A qualitative research approach was followed and a triangulation of data collection methods was used, combined with a relatively broad literature study to capture the complexity of the related issues. The contextual focus includes the macro-economic factors that contribute to the environment in which informal settlement fires occur, and furthermore, developmental, economic, political and social aspects and the related experience of poverty, urbanisation and unemployment. It was found that the theoretical underpinning of both the fields of Disaster Management and Community Development are relevant for analysis and addressing the research questions. Furthermore, that a relationship exists between the Disaster Management, Development and Community Development fields. This is particularly evident in Disaster Management policy and planning as related to prevention, mitigation, and public participation, such as community involvement in Community-Based Risk Assessments. Key findings suggest that local government in the demarcated study area has great influence on how the problem of informal settlement fires is addressed. From national to local municipality level, the State plays the largest role in addressing the issue and takes the responsibility for addressing informal settlement fires as part of disaster management mandates prescribed in legislation. The local government agenda as influenced by Disaster Management legislation include efforts related to awareness, education and training focused on Kayamandi as an informal settlement community and can be considered community development initiatives. This further relates to the view taken in the thesis that informal settlement fires are a social issue and not only an operational issue. Therefore the broad social, economic and political context and history were included and it was shown that the ‘problem’ of informal settlement fires is part of a greater developmental context and related processes. A variety of community development theories were chosen as a useful framework for analysis in this study and to approach issues of risk and vulnerability on a community level. It also presents a conceptual framework for including both non-governmental stake-holders and the affected community as role-players. / AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die kwessie van vure in informele nedersettings en spesifiek in Kayamandi, ‘n informele nedersetting van Stellenbosch in die Wes-Kaap provinsie van Suid- Afrika. Die doel van die studie is om die relevante rolspelers te identifiseer wat betrokke is by die aanspreek van die kwessie en om die unieke dinamika van vure in hierdie plaaslike konteks te verstaan. Hierdie studie beklemtoon die belangrikste kontekstuele faktore wat bydra tot die uitbreiding van informele nedersettings in Suid-Afrika en wat verband hou met die risiko en kwesbaarheid van inwoners van informele nedersettings. ‘n Kwalitatiewe navorsingsbenadering is gevolg en ‘n triangulasie van dataversamelingsmetodes is in hierdie studie gebruik. Dit is met ‘n relatief breë literatuur-studie gekombineer om die kompleksiteit van die verwante kwessies weer te gee. Die konteksuele fokus sluit in makro-ekonomiese faktore wat bydrae tot ‘n omgewing waarin informele nedersettingsbrande voorkom, en voorts, ontwikkelings-, ekonomiese-, politieke- en sosiale aspekte, sowel as die verwante ervaring van armoede, verstedeliking en werkloosheid. Daar is bevind dat die teoretiese begronding van beide die velde van Rampbestuur en Gemeenskapsontwikkeling relevant is vir ontleding en om die navorsingsvrae te kan beantwoord en dat daar ‘n verhouding tussen Rampbestuur, Ontwikkeling en meer spesifiek Gemeenskapsontwikkeling bestaan. Dit kom veral na vore in Rampbestuurbeleid en - beplanning soos van toepassing op voorkoming, mitigasie en publieke deelname. Van die belangrikste bevindinge suggereer dat die plaaslike regering in die gegewe studie die grootste invloed het oor hoe die probleem van brande in informele nedersettings aangespreek word. Van nasionale tot plaaslike vlakke neem die Staat die verantwoordelikheid vir die aanspreek van informele nedersettingsbrande, soos vervat in mandate wat deur rampbestuur wetgewing bepaal word. Die plaaslike regering se agenda soos bepaal deur Rampbestuur wetgewing bevat gemeenskapsontwikkelingsidees oor deelname en inklusiewe beplanning, bewusmaking, opvoeding en spesifieke opleidingsinitiatiewe wat op Kayamandi afgestem is. Dit sluit verder aan by die siening, soos geneem in die tesis, dat informele nedersettingsbrande meer as net ‘n operasionele kwessie is, maar ook ‘n sosiale dimensie insluit. Om hierdie rede word die breër sosiale, ekonomiese, politieke en historiese konteks in die studie ingesluit, soos wat dit op die ‘probleem’ van informele nedersettingsbrande as deel van die groter ontwikkelingskonteks en prosesse dui. ‘n Verskeidenheid van gemeenskapontwikkelingsteorieë is as ‘n bruikbare raamwerk geselekteer vir ontleding en as ‘n benadering om risiko en kwesbaarheid op gemeenskapsvlak aan te spreek. Dit bied ook ‘n konsepsuele raamwerk om beide nie-regeringsrolspelers en die geaffekteerde gemeenskap ook as rolspelers in te kan sluit.