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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
471

Rattan cane harvesting in Lambusango forest, Buton, Indonesia : a sustainable practice or a threat to forest conservation?

Widayati, Atiek January 2010 (has links)
Lambusango forest, Buton, Indonesia, houses the endemic and rare fauna species of Anoa (Bubalus depressicornis). It is also an important site for NTFP extraction. The most important NTFP is rattan cane (Calamus and Daemonorops), which is a common material for furniture and handicraft industries. The extraction has long taken place and is entirely manual harvesting of wild rattan canes by local villagers. With growing concerns about deforestation and forest encroachment in the tropics, NTFP extraction has been conceived as a means to balance forest conservation with the needs of local economies. However, the sustainability of rattan cane harvesting in Lambusango forest is unknown. This research assesses the extent of forest disturbance in Lambusango and its major forest-based livelihood activity: rattan cane harvesting. Assessments are undertaken to investigate the key factors affecting harvesting levels and to determine whether the current practice is sustainable. Sustainability assessments take into account resource sustainability, impacts on forest structure and economic importance to the harvesters. Forest loss to agricultural uses has mostly taken place in the forest peripheries while the core forest area shows much less change than other zones and there has also been some regeneration. The study area shows levels of woody biomass within the common range of tropical rainforests. Effects of natural factors on rattan plants and forest vegetation were assessed. Abundance and distribution of rattans are not influenced by natural factors of slope and light regime while soil pH has an effect on abundance of Calamus ornatus. It was found that tree species richness and diversity are affected primarily by topographical factors and the woody biomass and size of trees are slightly affected by soil factors. There is no significant evidence of an association between variations in tree and vegetation structure and variations in rattan abundance and presence. Harvest quantity is affected by natural factors such as terrain and accessibility, although they become less influential where the resource is abundant. Forestry laws enforced through the designated forest zone system (kawasan hutan) do not significantly affect levels of harvesting. Demographic and socioeconomic factors only marginally influence the economic importance of cane harvesting. There is some indication that more profitable, more intensive and less rigorous livelihood activities are favoured by some harvesters, making them less rattan dependent. Harvesting was found to impact understorey vegetation density and tree regeneration. A combination of natural competition and anthropogenic factors adversely affect tree-stem density. Maintaining a low level of harvesting can ensure resource sustainability. Two conceptual scenarios for the future of cane harvesting in Lambusango forest are discussed: sustainable harvesting and non-forest-based livelihoods. With a long-standing and important forest extraction activity such as rattan cane harvesting, sustainable harvesting is one pathway that can contribute to local livelihoods. Because evidence showed that only minimal impacts have occurred on forest structure and a sustainable harvest level can be maintained, efforts towards sustainable practice should be supported. Sustainable rattan cane extraction may work in combination with the ongoing efforts for sustainable management of Lambusango forest, such as those initiated by Lambusango Forest Conservation Programme (LFCP) and other potential schemes such as development of rattan agroforestry, certified NTFP and incentive-based mechanisms for forest protection.
472

Soil resource and production dynamics of a tree-grass intercropping system managed across gradients of interspecific competition

Krapfl, Kurt J. 27 August 2015 (has links)
<p> Belowground competition presents a threat to the production and sustainability of tree-grass ecosystems. Management scenarios designed to optimize the spatial and temporal distribution of soil resources will improve resource-use efficiency and promote greater co-production. We conducted three experiments to assess competition dynamics between loblolly pine and switchgrass. </p><p> In a three-year field trial, loblolly pine and switchgrass were intercropped across varying competitive intensities. Interspecific competition decreased loblolly pine annual growth; however, establishing vegetation exclusion zones surrounding pines largely mitigated these effects. Switchgrass yields were less affected by interspecific competition compared to pines and land equivalency ratios indicated that with proper management co-production yields may exceed those of switchgrass monoculture. Switchgrass was a constant and significant competitor across all years while loblolly pine resource use was minimal in year 1 but increased in subsequent years. </p><p> In a short-term greenhouse experiment, native soil was amended with biochar and inorganic N fertilizer and the effects of these amendments upon soil properties and switchgrass productivity were assessed. Biochar increased soil pH, total soil carbon, and soil moisture. However, N fertilization had negligible effects upon soil properties. Plant response to biochar was neutral to negative while N fertilization increased switchgrass foliar biomass but no interactive effects of the amendments were observed. Although the effects of biochar upon switchgrass production were trivial, its positive influence upon soil properties suggests a potential for mitigating competitive interactions. </p><p> Finally, a field-scale study examined co-production of loblolly pine and switchgrass over two years in response to competition control, biochar, and N fertilizer. As expected, interspecific competition reduced soil resources and decreased plant productivity. Biochar increased total soil C and soil moisture levels but had relatively minor impacts upon other aspects of soil fertility or plant production. Nitrogen fertilization acidified soil pH and decreased total soil C and N but positively affected loblolly pine foliar N concentrations and switchgrass yields. A positive association between soil inorganic N and switchgrass yield suggests the species competitive influence may be increased with greater N supply.</p>
473

Nocturnal activity of female desert mule deer

Hayes, Charles Laforest, 1966- January 1992 (has links)
I quantified nocturnal activity of female desert mule deer (Odocoileus hemionus crooki) in the Belmont and Bighorn Mountains, Arizona, 1990. I determined seasonal differences in percent of time active and distances moved at night from locations of radio-collared deer. I compared nocturnal home ranges and habitat use to those obtained from daytime locations. Activity differed among seasons (P = 0.046). Nocturnal activity was greatest in spring and summer, and decreased in winter. Movement distances also varied with seasons (P = 0.045). Most of the area of nocturnal home ranges (88%) fell within daytime home ranges. Use of habitat in relation to availability was consistent between day and night for 6 of 8 vegetation associations. Use of disturbed sites increased at night (P < 0.01).
474

Ecology of arctic grayling in Becharof Lake tributaries

Eaton, Dewey Mitchell, 1960- January 1993 (has links)
I studied the grayling populations in 4 tributaries of Becharof Lake. The grayling in Ruth River, and Salmon, Featherly and Becharof Creeks appear to be independent populations, with high fidelity to specific streams. All populations overwintered in the lake and migrated into the streams when water temperatures reached about 2.5 C. These populations contained some of the largest grayling in the state; generally >50% of the population exceeding 6 years in age and had fork lengths >400 mm. Interstream movement rates were about 2%, but intrastream movement was higher (18%). Spring migration into the streams extended from May-July. This extended migration may have invalidated the assumption of a closed population, and resulted in higher than actual estimated abundance. Abundance ranged from a low of 33 grayling/Km in Featherly Creek to a high of 230 grayling/Km in Becharof Creek. Survival rates were similar in all streams.
475

Habitat use and preference of Gila topminnow

Forrest, Robert Eugene, 1965- January 1992 (has links)
The Gila topminnow (Poeciliopsis occidentalis occidentalis) is federally and state listed as endangered. My objectives were to quantify microhabitat use and preference of topminnow in the field and test responses to controlled laboratory settings. In Cienega Creek, topminnow preferred stream margins where the water was calm, shallow, and contained aquatic vegetation. Topminnow were always near the water surface. Water temperature averaged 1-2 C warmer in areas occupied by fish. In outdoor pools, groups of topminnow consistently preferred cover provided over no cover and selected the upper 1/3 of the water column. Plastic strips, elicited the strongest response and styrofoam sheets elicited the weakest response. Topminnow did not show a consistent preference for cover when tested singly in aquaria, but showed a strong preference for calm water. Responses of topminnow to tests in aquaria were not in concordance with behavior observed in Cienega Creek or in tests conducted in outdoor pools.
476

Assessing the Benefits of a Virtual Transhipment Hub in the Swedish Forestry Industry

Danell, Gustav January 2014 (has links)
The purpose of this master thesis is to reduce the transportation costs and environmental distress by improving the transportation routes needed to supply the sawmills in the county of V¨asterbotten, Sweden, their raw material. It is of particular interest to explore the possible benefits of implementing a so called virtual transshipment hub for this purpose. The outline of the hub is to allow the companies within the system to deduce raw materials from other companies’ contracted harvesting areas. The hub would thus create a pool of the total raw material appointed by each specific company. These companies may deduce the raw material needed but can have it transported from a closer site than their own contracted lumbering area. Sawmill companies rely on the use of harvesting areas to provide the needed raw material and it is of common practice to contract different harvest areas. The thesis is that the permission to use other companies’ harvest areas would create new possible routes resulting in better planning and as an extension more efficient routes. This master thesis will investigate the current situation in the industry and adapt a model suitable for the purpose from the information gathered. This thesis work will also provide a number of cost allocation models which are used in cooperations between different companies in order to determine how to allocate the savings / costs between the companies. It was revealed in an interview that it was desired to include an exploration of the ETT trucks in this paper. The ETT trucks is a new type of truck which is not currently permitted in Sweden. It has a higher loading capacity than the conventional trucks used today. Gathering data proved much more difficult than initially anticipated. As a result, this paper will not provide any actual data testing, but the Results section will show that the model is working as intended by using with trivial data. More on the difficulties associated with the data in the section Discussion. Due to the trivial data it is impossible to express an actual cost saving in using a numerical value or percentage. The results from this survey did however show that there were a signification reduction of the cost associated with the transportation of raw material when the two companies tested cooperated in comparison to when they worked separately. The use of the ETT trucks would reduce the transportation costs and CO2 emissions by 20 % respectively, as presented in a survey conducted by L¨ofroth and Svenson (2012). The conclusion is that regardless if the government allows the use of ETT trucks, it should lie in the best interest to further explore the implementation of a virtual transshipment hub using real data and a thorough investigation of eligible participants through the cost allocation models and a subsequent maintenence of the system using supply chain management.
477

USING TERRESTRIAL LIDAR TO MODEL SHRUBS FOR FIRE BEHAVIOR SIMULATION

Adams, Theodore 02 April 2014 (has links)
The purpose of this study was to spatially represent shrub fuel matrices accurately and at fine resolution for use in physics-based fire behavior simulations. Terrestrial Light Detection and Ranging (T-LiDAR) was used to measure shrub fuel beds in laboratory settings before and after fire burned through them. The primary goals of this research were to produce highly descriptive data-sets that correctly identified the locations of biomass within 3-D space without destructive sampling, and to derive attributes for fuel elements within the shrubs. This research was completed in two phases. First, a series of experiments was conducted to test the capacity of a commercially available LiDAR instrument for making detailed measurements of diffuse shrubs. Second, model shrub fuel beds were produced and evaluated for accuracy. The research tested the T-LiDARs ability to characterize physical traits of shrubs within volumes, identified issues associated with misrepresenting the true geometry of scanned samples, developed sampling protocols for scanning shrubs prior to and following combustion experimentation, and built descriptive models of actual shrubs. The findings of this study show that T-LiDAR can be used effectively to estimate volume, structure, and biomass for individual shrubs. T-LiDAR derived models were shown to accurately predict mass of scanned shrubs (Adj. R2: 0.598, P-Value: 0.0012). The models produced show vast improvements from past estimations of physiological characteristics in fuels and fire behavior.
478

Scientia silvica extension series

Klinka, Karel 03 1900 (has links)
Scientia Silvica extension series was started in 1997 by Karel Klinka, a silvics professor at the University of British Columbia. He saw the need for a friendly way of distributing current research results to the forestry community. Each extension pamphlet represents a 2-4 page summary of research findings in the field of forest ecology. Topics range from humus form and ecosystem classification to forest productivity, regeneration, stand structure, soil nutrient regimes, coarse woody debris, and plant diversity. Included in each summary is a reference to the more technical original report or scientific paper and contact information for those who wish further information. Also included in the series are several full colour comprehensive reports on ecosystem classification. All pamphlets and reports are in Adobe Acrobat (PDF) format for on-screen viewing or printing. Forest Renewal British Columbia provided the funding for this version of Scientia Silvica extension series.
479

Wild edible plants (WEPs) and their contribution to food security: an analysis of household factors, access and policy in the semi-arid midlands of Kenya

Shumsky, Stephanie January 2013 (has links)
Food insecurity and malnutrition are issues that affect approximately one in seven people worldwide and climate change threatens to increase those risks in the future. Many of the policies that address future food systems emphasize resilience - a combination of flexibility in the face of disturbance and the capacity to adapt to change. In Sub-Saharan Africa many households employ livelihood systems that are highly sensitive to change and cannot adapt well to changing environmental conditions, leaving them vulnerable and reliant on coping strategies. Wild edible plants (WEPs) are a particularly common and effective strategy for coping with food insecurity. This research, conducted in rural Eastern Province, Kenya, suggests that certain demographic characteristics and access conditions are correlated with greater use of WEPs. Food insecure households, and those families lacking off-farm income or with lower levels of assets were found to consume WEPs with greater frequency. Access to WEPs was also a major factor, with smaller farm sizes and increased distance to harvest areas correlated significantly to lower levels of WEP use. After reviewing the existing laws pertaining to State forests, privatization trends of communal land and an increasingly formalized management regime for private land tenure, I find that access to WEPs is declining. Development practitioners', governments' and donor organizations' focus on commercialization and commodity value has led extension agents and land owners to ignore the subsistence value of WEPs, especially for poorer populations. The household characteristics identified in this study are specific enough that they can be used to determine the demographic groups that rely heavily on WEPs, and the access conditions that are likely to increase the ability of those vulnerable groups to employ WEPs as a coping strategy to increase system resilience. Protecting and promoting sustainable use of WEPs could increase the current contribution of these valuable resources to household food security, especially if policies can be tailored for the groups that depend on them the most. / L'insécurité alimentaire et la malnutrition affectent environ une personne sur sept à travers le monde et le changement climatique menace d'accroître ces risques à l'avenir. La plupart des politiques qui concernent les systèmes alimentaires futures mettent en relief la résilience - une combinaison de flexibilité face à la perturbation et la capacité de s'adapter au changement. En Afrique sub-saharienne de nombreux ménages utilisent des stratégies de moyens de subsistance qui sont très sensibles aux changements et ne peuvent bien s'adapter aux conditions environnementales, ce qui les rendent vulnérables et dépendants des stratégies de survie. L'utilisation des plantes sauvages comestibles (WEPs) représente une stratégie particulièrement commune et efficace. Cette recherche réalisée dans la Province de l'Est du Kenya suggère que certaines caractéristiques démographiques et conditions d'accès sont en corrélation avec une augmentation de la consommation de WEPs. Les lois forestières dans les zones de conservation, la privatisation des terres communales, et la formalisation des régimes de gestion contribuent à la réduction d'accès aux ressources WEP, tout en mettant l'accent sur la commercialisation et la valeur de ces produits pour l'export, ce qui a provoqué les agents de vulgarisation et les propriétaires fonciers à ignorer la valeur substantielle des WEPs, en particulier pour les populations les plus pauvres. La protection et la promotion de l'utilisation durable des WEPs pourraient augmenter la contribution actuelle de ces ressources importantes à la sécurité alimentaire des ménages, et d'autant plus si les politiques peuvent être adaptées pour les groupes qui dépendent le plus sur les WEPs.
480

Context to a conversation : the contribution of science to sustainable forestry

Cushon, Geoffrey Harold 11 1900 (has links)
The currently topical problems of forest management are issues of trans-science. They can be framed in the language of science but they cannot be resolved in the language of science. They involve historically contingent phenomena for which predictive certainty is not possible and they involve issues of moral, aesthetic and economic value. What is the role of science in contributing to the public debate on what are fundamentally social issues such as clear-cut logging or the preservation of old-growth forests? A history and philosophy of science, in general, and ecological science, in particular, is presented that traces the transition, over the last half century, from a positivist science of universal, timeless, predictable order to a science that attempts to interpret local, particular aspects of nature. The former relies on identifying restricted spatio-temporal scales that facilitate prediction while the latter focuses on an understanding of the causal relations within interrelated systems that facilitate explanation of system properties. A kind of contextual or dialectical holism is advocated wherein system components are considered in the context of the whole and the whole is considered as an epiphenomenon resulting from causal interaction of the parts. A history of forest science is presented that identifies sustained yield forestry as a construct of positivist science. Recent insights by ecological science, into the complexity and contingency of forest ecosystems, reveal the limitations of this simplified view. Moreover, the application of a single large-scale strategy such as sustained yield forestry to managing forests in British Columbia contained value assumptions that no longer reflect the full range of values that the public express. The currently topical debates on clear-cutting, logging in municipal watersheds and over-cutting are offered as examples of how questions of fact and questions of value become linked. Although these debates have been carried on in the language of science they are essentially social issues and cannot be resolved by science. The role of science in contributing to the resolution of social issues, such as the development of a sustainable forestry, is not to develop specific solutions but to contribute to the social dialogue in a subservient fashion. Science can characterize the context in which disagreements about matters of value take place. Science can use its experimental protocols to help society construct living experiments that allow us to learn our way into the future. Science can take part in an equitable conversation on sustainable forestry that will facilitate a better understanding of the beliefs and values of the human component of forested ecosystems.

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