Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 99-105).

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xvi, 149 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 138-149).

Thesis (M. P. A.)--Texas State University-San Marcos, 2009. / "Spring 2009." Includes bibliographical references (leaves 74-78).

No description available.

Thesis (doctoral)--Universidad de Santiago de Compostela, 1998.

A model was formulated to estimate tree component weight by geometrically describing the tree with basic tree parameters such as diameter, height, crown width, and crown length and the shape equations that relate them. The stem is divided into three sections with shape equations to describe the wood and bark in each section. The crown is divided into three sections with three equations. The main branch stems are described in three sections by six equations as in the stem. The shapes and their defining parameters provide a volume estimate for the tree components. The density of the wood and bark in each section of the stem and branches is estimated as a random variable. The density of the crown is defined by estimates of interwhorl distances and numbers of branches per whorl, both of which are random variables. The length of the branches also Influences the density of the crown because the weight of the needles and branchlets is a function of branch length. The density and volume of the components combine to give estimates of the weight of the components. In addition to this indirect calculation of tree component weight, the model calculates-the weight of individual tree components with equations having specific tree parameters as independent variables. The estimates of weight are used to calculate the quantity of slash per tree and the center of mass of each major tree component. The weights of the stump and the unmerchantable top are also calculated in conjunction with the slash calculations. The weights and centers of mass are produced in tabular form. The accuracy of the model is limited by the accuracy of the input data. The model was verified for Douglas-fir, western hemlock, and western redcedar. The verification procedure included manual calculations and comparison with other estimates of weight. The model in its present form can aid in understanding the quantitative effects on the tree of variation in the parameters which describe the tree. Because the weight and volume of the tree components influence their combustibility, the model can aid in describing the tree component of the forest fuel complex. New data and further analyses would be needed to determine the full potential and practical utility of the model described herein. / Forestry, Faculty of / Graduate

No description available.

No description available.

A dissertation submitted in fulfilment of the academic requirements for the degree of Masters of Environmental Science, School of Animal Plant and Environmental Sciences. University of the Witwatersrand. October 2016. / Fire and grazing are important drivers of grassland composition and function in savanna ecosystems. Fire alters the forage quality and vegetation structure, so changing fire regimes also changes grazer utilisation of the landscape. This study aimed to investigate how different fire regimes, specifically changes in fire size and season of burn, influence grazer attraction as well as grazing intensity and duration in the short-term, and further to determine how long-term fire-grazing interactions may influence the development of grazing lawns. In the short-term experiment, fires of three different sizes were applied in both the early dry season (EDS) and late dry season (LDS), and periodic collection of grass height and dung count data was conducted over a full year. Results showed that grazers were immediately attracted to the burned areas after the fires, and that fire and grazing together can maintain a short grazed patch for a full season. The greatest grazer visitation and grazing pressure (shortest grass) was observed on the intermediately sized burns (5ha). Furthermore, EDS treatments exhibited less initial grazer visitation but grass was kept in a short state for longer than on LDS burns. LDS burns had more intense grazing but over a much shorter time. For the long-term experiment, a long-standing fire experiment (Experimental Burn Plots, Kruger National Park, South Africa) was used to investigate change in grass community composition as influenced by firegrazing interactions over a 60 year period. Historical data were used, and grass composition data were also collected on three treatments that allowed for comparison of communities that experienced grazing and fires repeated at different fire frequencies and different seasons (April biennial and August annual burns), as well as a natural fire regime (control). By investigating the change in abundance in a few key grass species, grass ecological status classes, and grass functional guilds, results found that grasses associated with grazing lawns (stoloniferous, ‘disturbed’) increased in abundance, while grasses of bunch grass communities decreased, and that this change was more pronounced on April biennial burns. The results of this study show that small fires can act as a catalyst for grass community compositional and structural change by attracting grazers. Key words: Grazing lawns, fire size, fire season, pyric-herbivory, savanna. / TG2016

vi, 164 leaves : ill., tables, maps, photos ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1978) from the Dept. of Applied Mathematics, University of Adelaide