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Fire is a cultural phenomenon. It is among man's oldest tools, the first product of the natural world he learned to domesticate. Since the 1970's, fire has been utilized extensively in forest management practices. This study was designed to compare prescribed burning in the fall or the spring with hand cutting to reduce the overall height of vegetation. Ten scenic overlooks on the Blue Ridge Parkway were selected for treatment. The experiment is a randomized incomplete block design. Four permanent transects were delineated in each unit for vegetation sampling. Four one-by-five meter plots were sampled on each transect for the species and number of root crowns in three height classes: less than one meter, one to three meters and greater than three meters. Vegetation sampling was completed before and after treatment. Rate of spread was determined by non-directional grid sampling. Flame length was measured at five points within the sampling grid and fire intensity was calculated. Prescribed burning and hand cutting stimulate sprouting of existing vegetation. Repetitive burning is necessary to effectively control hardwood sprouting on the Parkway. Fire stimulated the herbaceous community and resulted in a significant increase in the species richness. Changes in soil characteristics were slight and did not degrade the site. Personnel costs were similar but burning required fewer hours of work. Decreases in the number of personal accidents and an expected decrease in the number of personnel required to successfully complete the burns favor the use of fire to control vegetation for forest vista management. / Master of Science

Canopy mortality. species abundance. and the species composition and origin of regeneration in mixed oak forests were studied following a 1900 ha man-caused early growing season wildfire in Shenandoah National Park. in the Blue Ridge Physiographic Province. Virginia. Pre-fire stands were dominated by chestnut. scarlet, and northern red oaks growing on medium quality sites (50 year upland oak site index 16-20 m). Permanent vegetation plots were established in four stands for each of high and low levels of fire intensity. and unburned stands. High-intensity fire killed 67% of the basal area and 81% of the trees, whereas low-intensity fire resulted in mortality of 8% of the basal area and 15% of the trees. The mean height of stem-bark char accounted for 91% and 95% of the variation in percent of the basal area and number of trees killed by fire, respectively. Logistic regression models were developed to predict the probability of fire-induced individual tree mortality (top-kill) as a function of DBH and height of stem-bark char for chestnut oak, scarlet and northern red oaks, pignut hickory, blackgum. and red maple. Blackgum and chestnut oak were the most fire resistant species studied. High-intensity fire resulted in the development of a new stand, whereas low-intensity fire resulted in thinning of the overstory and understory. Most species present in pre-fire stand reproduced via basal sprouts, chestnut oak sprouts were the most abundant stems taller than 1 m two growing seasons after high-intensity fire. Tree-of-heaven was the only species to regenerate by seed and able to match the height growth of oak basal sprouts. This research suggests that oaks are capable of replacing themselves on medium quality sites following wildfire-induced canopy removal in 55 to 60 year old stands. / Master of Science

Call number: LD2668 .T4 1985 J36 / Master of Science

Fuel accumulation rate and total soil nitrogen, phosphorus, and sulfur following prescribed fires were studied. Three prescribed fires were conducted in S.E. Arizona ponderosa pine stands during the summers of 1979, 1980, and 1981. Samples of forest floor and larger diameter fuel and soil from the surface 1.5 inches and 1.5 to 3.0 inch layers were collected in the summer of 1981. Forest floor and total fuel accumulation averaged 5.4 to 6.7 and 6.3 to 8.9 tons/acre/year, respectively. Total nitrogen, phosphorus, and sulfur in the surface three inches of mineral soil were not significantly affected by burning. Soil nitrogen, phosphorus, and sulfur content averaged 0.21%, 344 ppm and 150 ppm, respectively, in the surface 1.5 inches and 0.11%, 285 ppm and 74 ppm, respectively, in the 1.5 to 3.0 inch layer.

Apesar de vários estudos já terem examinado os efeitos de queimadas naturais, respostas das aves, como variação do padrão da comunidade, guilda trófica e das espécies, ao manejo de fogo ainda não foram investigadas em reservas do Cerrado, Este trabalho teve como objetivo comparar a avifauna em trechos de campo sujo manejados (aceiros) e não manejados por fogo no Parque Nacional das Emas, Brasil Central. Este é o primeiro trabalho a avaliar os efeitos do manejo do fogo prescrito sobre comunidades de aves no Cerrado. Foram selecionados 12 locais de estudo. Em cada local, havia um transecto no aceiro e outro em campo sujo não manejado. Uma amostra consistiu em percorrer um transecto de 800m a pé, anotando as aves detectadas visual ou auditivamente a 15m do observador. Frequência de ocorrência e abundância das espécies e das guildas tróficas, riqueza total, abundância total da comunidade de aves e composição de espécies encontradas nos dois ambientes foram comparadas. No total, foram 881 registros e 41 espécies de aves. A riqueza e a abundância total de aves foram significativamente menores em aceiros. Houve diferença na composição de espécies de aves entre campos não manejados por fogo e aceiros. Dentre as guildas tróficas, os onívoros foram mais frequentes em campos não manejados. Granívoros, nectarívoros e onívoros foram mais abundantes em vegetação não manejada. Das 21 espécies analisadas separadamente, a coruja Athene cunicularia foi a única indicadora de aceiros e também mais frequente e abundante em aceiros. Por outro lado, foram identificadas quatro espécies indicadoras de campos sujos não manejados (Melanopareia torquata, Xolmis cinerea, Neothraupis fasciata e Coryphaspiza melanotis). Tais espécies podem ser usadas como indicadores ecológicos do regime e histórico do fogo e podem fornecer informações se os objetivos das ações de manejo do fogo estão sendo atingidos. Sete espécies foram mais frequentes e oito espécies foram mais abundantes em campos não manejados. Três dessas espécies são endêmicas do Cerrado (M. torquata, N. fasciata e Cypsnagra hirundinacea) e quatro estão sob algum grau de ameaça e são altamente sensíveis a distúrbios (Polystictus pectoralis, Alectrurus tricolor, C. melanotis e C. hirundinacea). Assim, cuidado e atenção devem ser redobrados para essas espécies, pois possuem alto valor para conservação e menor frequência ou abundância em aceiros. A menor riqueza e abundância de aves encontrada em aceiros devem estar relacionadas ao menor uso desse habitat, indicando menor disponibilidade de recursos como alimento, reprodução e abrigo, dado que o fogo altera a estrutura e composição da vegetação. Isso demonstra uma diminuição da qualidade do ambiental geral dos aceiros, provocada pela sua atual forma de manejo. Propomos que a queima dos aceiros seja feita em intervalos de 3 anos, em vez de 1 2 anos como tem sido realizada. Dessa forma, seria mantida a função dos aceiros como controle e barreira efetiva de incêndios e também para conservação da biodiversidade. / Several studies have investigated the effects of natural fires on Cerrado birds. However, avian responses to fire management have not been examined. We compared birds found in firebreaks (fire managed areas) and in fire unmanaged grasslands, in Parque Nacional das Emas, Central Brazil. This is the first study to evaluate the effects of prescribed fire on the Cerrado avifauna. We selected 12 study sites. We established one transect in the firebreak and another one in an unmanaged grassland area in each study site. Each bird count sample consisted of walking through an 800m transect recording birds seen or heard 15m from the observer. Species richness, total bird abundance, species composition, feeding guilds abundance and frequencies of occurrence and species abundance found in firebreaks and unmanaged grasslands were compared. In total, 881 individuals and 41 species were recorded. Species richness and total abundance were significantly lower in firebreaks. Species composition was different between firebreaks and unmanaged grasslands. Omnivores were more frequent and more abundant in unmanaged grasslands. Granivores and nectarivores were more abundant in unmanaged grasslands. Twenty-one bird species were analyzed separately, one of which (Athene cunicularia) was indicator of firebreaks and also more frequent and abundant in firebreaks. On the other hand, we identified four indicator species of unmanaged grasslands (Melanopareia torquata, Xolmis cinerea, Neothraupis fasciata and Coryphaspiza melanotis). These species might be used as ecological indicators of fire regime and history, and also give information if fire management goals are being achieved. Seven species were more frequent and eight species were more abundant in unmanaged grasslands. Three of them are endemic of Cerrado (M. torquata, N. fasciata and Cypsnagra hirundinacea) and four of them are highly sensitive to human disturbances and threatened with extinction in some degree (Polystictus pectoralis, Alectrurus tricolor, C. melanotis e C. hirundinacea). Caution must be redoubled to these species, as they are of high conservation priority and less frequent and abundant in firebreaks. The lesser avifauna complexity in firebreaks than in unmanaged areas might be connected to the low use of this habitat, thus indicating lower resource availability, such as food, sites for reproduction and refuge. This is because fire changes vegetation structure and composition. We propose that firebreaks should be burnt every 3 years, instead of 1-2 years. In this way, fire management would keep its function as effective fire barriers and would also keep biodiversity conservation.

Fire is used in the management of ecosystems worldwide because it is a relatively inexpensive means of manipulating thousands of hectares of vegetation. Deciding how, where and when to apply fire depends primarily on the management objectives of the area concerned. The decision to ignite vegetation is generally subjective and depends on the experience of the fire manager. To facilitate this process, ancillary tools, forming a decision support system, need to be constructed. In this study a spatial model has been developed that is capable of simulating fire dynamics in savanna ecosystems. The fire growth model integrates spatial fuel and topographic data with temporal weather, wind settings and fuel moistures to produce a time-evolving fire front. Spatial information required to operate the model was obtained through remote sensing techniques, using Landsat Thematic Mapper (TM) satellite imagery, and existing Geographic Information Systems (GIS) coverage's. Implementation of the simulation model to hypothetical landscapes under various scenarios of fuel, weather and topography produced fire fronts that were found to be in good agreement with experience of observed fires. The model was applied actual fire events using information for prescribed burning operations conducted in Mkuze Game Reserve during 1997. Predicted fire fronts were found to accurately resemble the observed fire boundaries in all simulations. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1999.

Promotion of a predictive understanding of plant community response to various forms, frequencies and seasons of disturbance, either through the direct physical effect on biota and or indirect effect on plants, through modification of microclimate and soil attributes is currently a major goal in plant ecology. In particular, the effect of disturbance on altering the ratio between available light and nutrients and their resultant effect on growth, shoot/root allocation, and thus community composition has gained considerable recognition in connection with the mechanisms of plant succession under a popular heading "the resource ratio hypothesis of plant succession". Contemporary and long-term (>50 years) burning and mowing experiments in KwaZulu-Natal (KZN) provide important sites for investigation that in the mesic grasslands of KZN, community composition changes in response to the frequency, time and type of disturbances such as burning, mowing and veld fertilization. However, the relationship between disturbance-resource-plant traits and their interactive role in species change is virtually unknown. This study sought to improve understanding of mesic grassland dynamics in. KZN, using short-term pot and plot experiments. The principal objectives were: 1) by subjecting plants to different levels of resources viz. light, nutrients, water and cutting to determine the relative above and below-ground growth performances (biomass allocation) of species from contrasting habitat preference in KZN, which implies their relative competitive ability for limiting resources and tolerance to cutting, 2) by using a short-term (one-season period) burning and mowing experiment to determine the effect of different veld management practices on microclimate and availability of soil resources and their subsequent effect on plant growth performances, 3) testing the relative shade tolerance of representative species from contrasting habitat preferences, 4) by combining the outcomes from these experiments, to provide a general synthesis concerning species' response to disturbance/resource which further signifies species change. The hypothesis that competitive ability as a function of biomass allocation is fertility dependent was supported by a pot experiment. In low nutrient treatments short grass species that predominate infertile soils in KZN viz. Aristida funcifarmis and Themeda triandra attained double the shoot biomass, more than double root biomass, initiated more tillers and re-grew better (after cutting) than those inherently tall species that predominate fertile sites viz. Eragrostis curvula and Hyparrhenia hirta. In contrast, in high nutrient treatments, tall species attained far higher shoot biomass and grew taller in height. Interestingly, short species had a smaller shoot: root ratio than tall species, consistent with the prediction of the resource ratio hypothesis. However, no evidence was obtained suggesting that tall species were more shade tolerant than short species. A field-based shade experiment rather showed that, those species that initiate tillers below-ground viz. Aristida junciformis, Eragrostis curvula and Tristachya leucothrix were more shade tolerant than those species that initiate tillers above-ground viz. Hyparrhenia hirta and Themeda triandra. On the other hand, the effect of disturbance/resource relationship in influencing the growth (biomass production, growth rate, and basal circumference) of contrasting species was examined by conducting a short-term (one season) burning and mowing experiment. The effect of disturbance, its form and frequency through its effect on light and soil moisture was able to account for a substantial difference in species vigour, which can potentially impact community composition. Short species (Themeda triandra and Tristachya leucothrix) showed their highest biomass production and higher basal circumference enlargement in burnt summer mown sites, whereas medium to tall species (Aristida junciformis, Eragrostis curvula and Hyparrhenia hirta) were less tolerant to summer mowing. Aristidajunciformis and Eragrostis curvula appeared to be more vigorous (both in terms of above-ground biomass production and growth rate) in burnt but not mown and control treatment respectively. High biomass and litter accumulation on sites protected from disturbance appeared to have a large influence on species vigour. Species such as Aristida junciformis, Eragrostis curvula and Tristachya leucothrix had high tolerance to litter accumulation while in contrast Hyparrhenia hirta and Themeda triandra were more vulnerable. In total this study has revealed that the association of some short species e.g. Themeda triandra with the reccurrence of disturbance is mainly due to increases in light availability and lowered dominance from tall species in frequently disturbed sites rather than nutrient related. However, this study has revealed that there are some indications whereby the notion that the inverse relationship between available light and nitrogen are important driving variables in species change is an important working theory in the mesic grassveld of KZN. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Thesis (Ph. D.)--University of Adelaide, 2005. / Title from PDF title page (viewed on July 9, 2005). Includes bibliographical references (p. 138-146).