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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.
191

COMPARATIVE ECOPHYSIOLOGY OF AMERICAN CHESTNUT UNDER DIFFERENT PLANTING TREATMENTS ON RECLAIMED MINE SITES

Miller, Christopher Ryan 01 May 2010 (has links)
American chestnut was once an abundant species that dominated the Eastern U.S. deciduous forests. Although this species is currently functionally extinct due to the chestnut blight, researchers are working on blight-resistant hybrids in hopes of restoring the species. As one potential vector for chestnut reintroduction and dispersal, the reclamation of mine sites are being considered. Recent research has found that reforestation efforts on these reclaimed mine sites provide productive tree growth while also complying with mine-reclamation laws. Understanding how American chestnut performs physiologically on mine sites will aid in the restoration of this species and reclamation of mine sites. The objective of this study was to determine the effect planting treatments have on survival, physiology, and performance of American chestnut. The response of American chestnuts under planting treatments varying in planting method, slow-release fertilizer, a hydrophilic root polymer (Terra-Sorb), and the addition of native forest soil were examined at three sites: a mine site, a quarry, and a greenhouse. Results from this study suggest that fertilizer, hydrophilic root polymers and soil microorganisms produce varying effects on dissimilar sites. Greatest overall survival was found in greenhouse-grown bare-root seedlings. The introduction of fertilizer to the soil substrate lowered emergence and survival of directly-seeded trees at the mine site and quarry, but increased tree growth at all sites and photosynthetic rate at the quarry. However, use of fertilizer resulted in a more negative water potential at the mine site and higher transpiration rate, potentially increasing moisture stress and demand. Increased seed survival, growth, and water status can be accomplished through the use of Terra-Sorb, but only in direct seeded trees on sites with potentially deficient plant-available water. Native forest soil can increase survival in both direct seeded and bare-root planted trees. However, more research is needed on the benefits of native forest soil, as growth and physiological results conflict. It is recommended that site characterization be performed prior to selection of planting treatments. Results of this study can prove beneficial to reclamation specialists with an interest in using mine site reclamation in conjunction with American chestnut restoration.
192

Essays on the Evaluation of Land Use Policy: The Effects of Regulatory Protection on Land Use and Social Welfare

Andam, Kwaw Senyi 24 October 2007 (has links)
Societies frequently implement land use policies to regulate resource extraction or to regulate development. However, two important policy questions remain unresolved. First, how effective are land use regulations? Second, how do land use regulations affect socioeconomic conditions? Three issues complicate the evaluation of land use policies: (1) overt bias may lead to incorrect estimates of policy effects if implementation is nonrandom; (2) the policy may affect outcomes in neighboring unregulated lands; and (3) unobservable differences between regulated and unregulated lands may lead to biased assessments. Previous evaluations of land use policies fail to address these sources of bias simultaneously. In this dissertation, I develop an approach, using matching methods, which jointly accounts for these complications. I apply the approach to evaluate the effects of Costa Rica s protected areas on land use and socioeconomic outcomes between 1960 and 2000. I find that: (1) protection prevented the deforestation of only 10 percent or less of protected forests; (2) protection resulted in reforestation of only 20 percent of non-forest areas that were protected; (3) protection had little effect on land use outside protected areas, most likely because, as noted above, protected areas had only small effects on land use inside protected areas; and (4) there is little evidence that protected areas had harmful impacts on the livelihoods of local communities: on the contrary, I find that protection had small positive effects on socioeconomic outcomes. Furthermore, the methods traditionally used to conduct such evaluations are biased. In contrast to the findings above, those conventional methods overestimated the amount of avoided deforestation and erroneously implied that protection had negative impacts on the livelihoods of local communities. This dissertation contributes to policymaking by providing empirical measures of protected area effectiveness. Although annual global expenditures on protected areas are about $6.5 billion, little is known to date about the returns on these investments. This study also indicates that policymakers should give careful consideration to current proposals to compensate communities living in or around protected areas: contrary to widely held assumptions, the findings suggest that protection may not have harmful effects on socioeconomic outcomes.
193

COMPARATIVE ECOPHYSIOLOGY OF AMERICAN CHESTNUT UNDER DIFFERENT PLANTING TREATMENTS ON RECLAIMED MINE SITES

Miller, Christopher Ryan 01 May 2010 (has links)
American chestnut was once an abundant species that dominated the Eastern U.S. deciduous forests. Although this species is currently functionally extinct due to the chestnut blight, researchers are working on blight-resistant hybrids in hopes of restoring the species. As one potential vector for chestnut reintroduction and dispersal, the reclamation of mine sites are being considered. Recent research has found that reforestation efforts on these reclaimed mine sites provide productive tree growth while also complying with mine-reclamation laws. Understanding how American chestnut performs physiologically on mine sites will aid in the restoration of this species and reclamation of mine sites. The objective of this study was to determine the effect planting treatments have on survival, physiology, and performance of American chestnut. The response of American chestnuts under planting treatments varying in planting method, slow-release fertilizer, a hydrophilic root polymer (Terra-Sorb), and the addition of native forest soil were examined at three sites: a mine site, a quarry, and a greenhouse. Results from this study suggest that fertilizer, hydrophilic root polymers and soil microorganisms produce varying effects on dissimilar sites. Greatest overall survival was found in greenhouse-grown bare-root seedlings. The introduction of fertilizer to the soil substrate lowered emergence and survival of directly-seeded trees at the mine site and quarry, but increased tree growth at all sites and photosynthetic rate at the quarry. However, use of fertilizer resulted in a more negative water potential at the mine site and higher transpiration rate, potentially increasing moisture stress and demand. Increased seed survival, growth, and water status can be accomplished through the use of Terra-Sorb, but only in direct seeded trees on sites with potentially deficient plant-available water. Native forest soil can increase survival in both direct seeded and bare-root planted trees. However, more research is needed on the benefits of native forest soil, as growth and physiological results conflict. It is recommended that site characterization be performed prior to selection of planting treatments. Results of this study can prove beneficial to reclamation specialists with an interest in using mine site reclamation in conjunction with American chestnut restoration.
194

Reforestation, Renewal, and the Cost of Coal: Opposing a Manichean Worldview in Central Appalachia

Hansen, Elizabeth R 01 January 2015 (has links)
Surface coal mining is a major form of land change and environmental degradation in Central Appalachia. Traditional mine reclamation iresults in unmanaged, unproductive grasslands that fail to mitigate many of the environmental costs of coal mining and are of minimal use to communities. Forestry reclamation is an alternative reclamation tactic that has the potential to address both environmental and socioeconomic concerns in Central Appalachia. A case study of Laurel Fork Mine in Eastern Kentucky is included.
195

Revegetation of coal spoils in Minto, N.B.: edaphic and ground cover responses to three management regimes

Pigot, Margaret. January 1984 (has links)
No description available.
196

Landowner decisions and motivations on the Tennessee northern Cumberland Plateau willingness to participate in government assistance programs and reasons for owning woodland /

Kaetzel, Brandon Russell, January 2008 (has links) (PDF)
Thesis (M.S.)--University of Tennessee, Knoxville, 2008. / Title from title page screen (viewed on Sept. 15, 2009). Thesis advisor: Donald G. Hodges. Vita. Includes bibliographical references.
197

Future Forests - Vision 2030 : Bachelor Thesis Report - Jenny Holmsten

Holmsten, Jenny January 2015 (has links)
Forests cover about 30% of the earth surface and is a vital resource as a habitat for plants, animals and humans. Today climate change and global warming is a fact and something must be done. We burn massive amounts of fossil fuels and during this combustion carbon dioxide is created. To help eliminate this global change we need to start caring about the forests. The forests have a major role in climate change and global warming. It currently contributes to about one-sixth of the global carbon emissions. But today deforestation is a real environmental threat. The world trees are being cut down too quickly for the earth to regenerate new forests. And while the society is moving into a more bio-based economy the pressure of a efficient forest industry and forest regrowth is increasing drastically. A new way of reforestation must happen, a sustainable and natural method must be im plemented. In Sweden and the Scandinavian area the method has had a stagnant development. Is done manually with a standardized procedure not taking natural properties into account. Money often goes over quality. My project will focus on developing a concept that can live up to the upcoming future demands and the environmental aspects that needs to be taken in account to ensure a healthy and sustainable forest. The final result performs an efficient and precise reforestation and enables for a detailed planning and analysis of the area in advanced.
198

Desenvolvimento inicial de guanandi (Calophyllum brasiliense Cambess., Clusiaceae) em sistema sob cobertura e a pleno sol / Early development of guanandi (Calophyllum brasiliense Cambess. Calophyllaceae) full-sun and under canopy cover planting systems

Wanginiak, Thayana Cristina Rebello 01 March 2016 (has links)
Submitted by THAYANA CRISTINA REBELLO WANGINIAK null (thayana@florestal.eng.br) on 2016-05-06T14:22:22Z No. of bitstreams: 1 TESE THAYANA AUTOARQUIVAMENTO.pdf: 1142126 bytes, checksum: 3b3e38c45ec67f41d8a7fc4ca41f8da0 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-05-09T18:52:39Z (GMT) No. of bitstreams: 1 wanginiak_tcr_me_bot.pdf: 1142126 bytes, checksum: 3b3e38c45ec67f41d8a7fc4ca41f8da0 (MD5) / Made available in DSpace on 2016-05-09T18:52:39Z (GMT). No. of bitstreams: 1 wanginiak_tcr_me_bot.pdf: 1142126 bytes, checksum: 3b3e38c45ec67f41d8a7fc4ca41f8da0 (MD5) Previous issue date: 2016-03-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A busca por espécies florestais nativas com potencial econômico tem sido crescente, assim como o aumento da demanda de madeiras nobres para fins comerciais. Todavia, muitas vezes pouco se sabe sobre o ciclo de desenvolvimento, tratos silviculturais e manejo adequados para cada espécie. Dentre as espécies que vêm se destacando na silvicultura de espécies nativas está o guanandi, Calophyllum brasiliense Cambess (Calophyllaceae), que apresenta características silviculturais e de qualidade de madeira favoráveis, além da produção de frutos e sementes o que incrementa a lucratividade e possuem propriedades medicinais. Embora a espécie seja capaz de se regenerar naturalmente no interior de florestas higrófilas, é cultivada usualmente em plantios puros a pleno sol, e as informações a respeito do melhor sistema de cultivo são escassas. Buscamos com este trabalho o conhecimento sobre o melhor sistema de plantio para a espécie: sombreado ou a pleno sol. A hipótese inicial da pesquisa era de que as plantas em sistema sombreado teriam melhor crescimento e maior sobrevivência do que as de pleno sol, assim como maior tolerância à seca, por este sistema se assemelhar mais às condições de seu habitat natural. O experimento foi delineado em blocos ao acaso com dois tratamentos (pleno sol e sombreado) e três repetições, com parcelas compostas por 30 plantas. Para as análises, cada planta foi considerada uma medida repetida dentro do fator bloco. As variáveis analisadas foram: sobrevivência, crescimento em altura e em diâmetro da base do colo. Foram também feitas análises fisiológicas das plantas sobreviventes em ambos os sistemas, com estimativas da condutância estomática, potencial hídrico da folha e conteúdo relativo de água. O microclima foi monitorado durante o período de estudo e foram feitas também análises de fertilidade radiação fotossinteticamente ativa (PAR) e umidade do solo. O verão de 2014 (janeiro a março) foi extremamente quente e seco, o que provocou uma alta mortalidade das plantas. Nossa hipótese não foi confirmada, uma vez que as plantas a pleno sol demonstraram melhor sobrevivência, maior crescimento e maior condutância estomática do que as sombreadas, contrariando nossa predição inicial. Embora as condições microclimáticas do sistema sombreado tenham sido mais favoráveis (menores temperaturas máximas, maior umidade relativa do ar), a umidade do solo foi maior no sistema a pleno sol. A maior mortalidade e menor crescimento no sistema sombreado podem ser atribuídos à maior competição por água com as árvores já estabelecidas no sistema sombreado, já que neste ambiente a menor umidade do solo indicaram um maior consumo de água pelas plantas já estabelecidas. / Recently there’s a growing interest in native forest species with economic potential, due to an increasing demand for hardwood timber species. However, to date there is not enough information about developmental cycles, silvicultural treatments and management required by each species. “Guanandi”, Calophyllum brasiliense Cambess (Calophyllaceae), is one of these high potential species due to its silvicultural and wood quality characteristics, besides providing fruits and seed with medicinal properties. Although the species usually regenerates naturally within hygrophyllous forests, it has usually been cultivated as pure stands under full sun. We aimed at investigating the more adequate planting system for C. brasiliense: shaded (enrichment plantings) or under full-sun conditions. Our hypothesis was the plants in shaded system would have better growth and higher survival, as well as greater drought tolerance, as this system is more similar to the species’ natural habitats. We used a randomized block design with two treatments (full-sun and under canopy cover) and three replicates, with 30 within-block repeated measures (plants per plot). The variables analyzed were survival, height and basal diameter growth; stomatal conductance and photosynthetic active radiation (PAR). The microclimate was monitored during all over the study period and soil samples were analyzed for fertility and moisture. The summer of 2014 (January-March) was extremely hot and dry, which caused high plant mortality rates. Our hypothesis was not confirmed, since plants under full-sun had better survival, higher growth and higher stomatal conductance, despite the drier and warmer microclimatic conditions. This shall be attributed to increased competition for water with the canopy trees in the shaded system, as soil moisture was higher in the full-sun plots, in spite of the hotter and drier microclimate.
199

Comportamento do capim-vetiver (Chrysopogon zizanioides (L.) Roberty) como contribuição na estabilização de talude da margem Rio São Francisco / Behavior of vetiver grass (Chrysopogon zizanioides (L.) Roberty) as a contribution in stabilization in the slope margins São Francisco River

Machado, Lorena 19 February 2014 (has links)
The changes in the hydrological regime in the São Francisco River basin, due to the implementation of hydroelectric power dams, are causing low water levels and therefore the bank erosion promoted by the riverbank undercutting. These changes, along with deforestation of riparian vegetation require economically viable and efficient measures since been affecting the population of the Lower São Francisco. The objective of this study was to evaluate the behavior of the root system of vetiver grass (Chrysopogon zizanioides) in ordet o evaluate its ability to restructuring physical soil mechanics and suitability to the process of stabilization of erosion of banks, as well as evaluate its effect on the soil penetration resistance (PR). To evaluate the influence of the grass on soil shear strength Root Density (RL), the Root Length Density (RLD), the Root Area Ratio (RAR), the Root Tensile Strength (TR) and the Root Cohesion (CR) were measured. The results were subjected to analysis of variance (p <0.05) using the SISVAR and then was held the polynomial regression analysis. To evaluate the RP, sampling was carried out near vetiver grass cultivation and the rows between crops along the profile until a depth of 0.60 m. The soil water was determined by weighing method, the RP by an automated penetrometer, the particle-size analysis by densitometry and root density by the monolith method. The results of RP, moisture and root density were subjected to analysis of variance (p <0.05) and afterwards the means were compared by Tukey test using the software SISVAR. For DR, DCR and RAR layer 0-0.10 m showed higher results which yielded 4.84 kg m-3, 12.45 km m-3, 1.66%, respectively. While the average result of TR was 83 MPa and CR 528 kPa. The vetiver grass near points had a mean RP of 1793.94 kPa and average soil water of 11.78%, differing from the sampled points in the rows between crops. The PR and soil moisture were not statistically different throughout the depths. The vetiver grass promoted ground cover, favoring a higher water retention and consequently decreasing the RP, as well as helping to increase the soil shear strength, giving a very important contribution to slope stabilization. / As alterações do regime hidrológico na bacia hidrográfica do Rio São Francisco, devido à implantação da cascata de hidrelétricas, estão causando baixos níveis de água e consequentemente erosão nos taludes do rio pelo solapamento da sua base. Essas alterações, juntamente com o desmatamento da mata ciliar requerem medidas economicamente viáveis e eficientes, visto que vêm afetando a população do Baixo São Francisco. Esse estudo teve como objetivo avaliar o comportamento do sistema radicular do capim-vetiver (Chrysopogon zizanioides) quanto à capacidade de reestruturação físico-mecânica do solo e à adequação ao processo de estabilização da erosão dos taludes, assim como avaliar o seu efeito na resistência do solo à penetração (RP). Para avaliar a influência da gramínea na resistência ao cisalhamento do solo, foram mensuradas a Densidade Radicular (DR), a Densidade do Comprimento Radicular (DCR), a Razão de Raiz por Área (RAR), a Resistência de Raízes à Ruptura (TR) e a Coesão da Raiz (CR). Os resultados foram submetidos à análise de variância (p<0,05) utilizando o SISVAR e em seguida realizou-se a análise de regressão polinomial. Para avaliar a RP, foram realizadas amostragens em pontos localizados próximos ao capim-vetiver e nas entrelinhas de cultivo, ao longo do perfil até a profundidade de 0,60 m. O teor de umidade foi determinado por pesagem, a RP por um penetrômetro automatizado, a análise granulométrica por densimetria e a densidade de raízes pelo método do monólito. Os resultados da RP, da umidade e da densidade de raízes foram submetidos à análise de variância (p<0,05) e posteriormente as médias foram comparadas pelo teste de Tukey usando o software SISVAR. Para DR, DCR e RAR, a camada de 0-0,10 m apresentou maiores valores com 4,84 kg m-3, 12,45 km m-3, 1,66%, respectivamente. Enquanto que o resultado médio de TR foi de 83 MPa e o de CR de 528 kPa. Os pontos próximos ao capim-vetiver apresentaram RP média de 1793,94 kPa e umidade média de 11,78%, diferindo estatisticamente dos pontos amostrados nas entrelinhas de cultivo. A RP e a umidade do solo não diferiram estatisticamente nas profundidades. O capim vetiver promoveu a cobertura do solo, favorecendo a maior retenção de água e, consequentemente, diminuindo a RP, além de favorecer o aumento da resistência ao cisalhamento do solo, auxiliando na estabilização de taludes.
200

Métodos para regeneração de áreas alteradas na fazenda experimental da Universidade Federal do Amazonas – Amazônia Central

Nogueira, Wanda Lemos Paixão 22 June 2015 (has links)
Submitted by Kamila Costa (kamilavasconceloscosta@gmail.com) on 2015-08-21T13:32:36Z No. of bitstreams: 1 Dissertação - Wanda L P Nogueira.pdf: 1028716 bytes, checksum: 49e3f0e14129c7efe528c410c9f8734f (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-08-28T20:30:25Z (GMT) No. of bitstreams: 1 Dissertação - Wanda L P Nogueira.pdf: 1028716 bytes, checksum: 49e3f0e14129c7efe528c410c9f8734f (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-08-28T20:36:12Z (GMT) No. of bitstreams: 1 Dissertação - Wanda L P Nogueira.pdf: 1028716 bytes, checksum: 49e3f0e14129c7efe528c410c9f8734f (MD5) / Made available in DSpace on 2015-08-28T20:36:12Z (GMT). No. of bitstreams: 1 Dissertação - Wanda L P Nogueira.pdf: 1028716 bytes, checksum: 49e3f0e14129c7efe528c410c9f8734f (MD5) Previous issue date: 2015-06-22 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / On the importance of the Amazon Biome and its role in the maintenance of terrestrial biodiversity and ecological balance of the planet, the control of deforestation has been a constant challenge in the management of environmental conservation. Thus, the revegetation of degraded areas through initiatives of reforestation with native tree species or by conduct of natural regeneration are potential strategies for the reintroduction of these areas to ecological and productive processes. This study had as main objective to investigate the effectiveness of two methods of regeneration for the recovery of altered areas in the Fazenda Experimental of the Universidade Federal do Amazonas (FAEXP-UFAM). The study area had its forest cover removed and after abandoning two experiments were implemented, namely: 1) conduct of natural regeneration and 2) planting of eleven native forest species belonging to different ecological groups, pioneers (six) and no pioneers (five). In experiment 1 were sampled in 9 x 15 m plots all trees individuals with height above 10 cm. The experiment 2 was installed in randomized blocks design, being five blocks with 50 saplings each. Monitoring the survival and height growth, diameter and crown area was held for 10 months. In the analysis of natural regeneration (experiment 1) showed a total of 148 individuals distributed into eight botanical families, nine genera and 13 species, being the species Vismia gracilis, Vismia cayennensis and Vismia guianensis, the species had the highest importance value. Individuals have focused predominantly on the class of intermediate size (0.3 < 1.5 m tall) of natural regeneration. Ten months after planting in the field (experiment 2), high (≥ 80%) survival of the species in both the ecological groups, with the exception of pioneer species Sclerolobium paniculatum (40%) and species not pioneer Cedrela odorata (67%). Among the pioneering species, the largest growths were observed for Ochroma pyramidale and Trattinickia rhoifolia. For the ecology group of not pioneer species, the best growth performances were achieved by Parkia velutina, Hymenaea courbaril, Cedrela odorata and Endlicheria anomala. The study area is in early stages of succession, and enrichment planting of species of better survival and growth could be most effective strategy for forest recovery to a lesser period of time. / Diante da importância do Bioma Amazônia e o seu papel para a manutenção da biodiversidade terrestre e para o equilíbrio ecológico do planeta, o controle do desmatamento tem sido um constante desafio na gestão da conservação ambiental. Assim, a revegetação de áreas degradadas por meio de iniciativas de reflorestamento com espécies arbóreas nativas ou pela condução da regeneração natural constituem estratégias potenciais para a reintrodução dessas áreas aos processos ecológicos e produtivos. O presente estudo teve como objetivo principal investigar a eficiência de dois métodos de regeneração para a recuperação de áreas alteradas na Fazenda Experimental da Universidade Federal do Amazonas (FAEXP-UFAM). A área de estudo teve sua cobertura florestal removida e após o abandono foram implantados dois experimentos, a saber: 1) condução da regeneração natural e 2) plantio de mudas de onze espécies florestais nativas pertencentes aos grupos ecológicos, pioneiras (seis) e não pioneiras (cinco). No experimento 1 foram amostrados em parcelas de 9 x 15 m todos os indivíduos arbóreos acima de 10 cm de altura. O experimento 2 foi instalado em delineamento de blocos casualizados, sendo cinco blocos com 50 mudas cada. O monitoramento da sobrevivência e do crescimento em altura, diâmetro e área de copa foi realizado durante dez meses. Na análise da regeneração natural (experimento 1) observou-se um total de 148 indivíduos distribuídos em oito famílias botânicas, nove gêneros e 13 espécies arbóreas, sendo as espécies Vismia gracilis, Vismia cayennensis e Vismia guianensis, as espécies que apresentaram maior Valor de Importância. Os indivíduos concentraram-se predominantemente na classe de tamanho intermediária (0,3 < 1,5 m de altura) da regeneração natural. Aos dez meses após o plantio em campo (experimento 2), observou-se alta sobrevivência (≥ 80%) das espécies em ambos os grupos ecológicos, à exceção da espécie pioneira Sclerolobium paniculatum (40%) e da espécie Não Pioneira Cedrela odorata (67%). Dentre as espécies pioneiras, os maiores crescimentos foram observados para Ochroma pyramidale e Trattinickia rhoifolia. No grupo ecológico das espécies não pioneiras, os melhores desempenhos em crescimento foram alcançados por Parkia velutina, Hymenaea courbaril, Cedrela odorata e Endlicheria anomala. A área estudada encontra-se em estágio inicial de sucessão, sendo o plantio de enriquecimento das espécies de melhor sobrevivência e crescimento estratégia mais efetiva para a recomposição florestal em menor período de tempo

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