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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.
61

Properties and Potentials of Coal Mine Soils in Southwest Virginia 29 Years After Establishment

Craig, Nina Genevieve 17 January 2013 (has links)
Current reclamation research following surface mining in the Appalachian coal region seeks to measure carbon (C) and nutrient accumulation and retention under forest vegetation to better understand the role of reforestation in the re-establishment of these ecosystem services. This study capitalized on the Controlled Overburden Placement Experiment (COPE), a 29-year-old reclamation research installation in southwestern Virginia, to estimate long-term mine soil C sequestration potentials and nutrient capitals after different reclamation strategies. The COPE includes two studies, a rock mix study (RM) comparing topsoil substitutes created from different ratios of local overburden [pure sandstone (SS), pure siltstone (SiS), 2:1 SS to SiS, 1:1 SS to SiS, and 1:2 SS to SiS], and a surface amendment study (SA) comparing organic amendments [control (CON), natural topsoil (TS), sawdust (SD), and 22 Mg ha-1 (22B), 56 Mg ha-1 (56B), 112 Mg ha-1 (112B) and 224 Mg ha-1 (224B) of biosolids] on a common 2:1 SS to SiS topsoil substitute. In the RM, overburden selection significantly affected soil nitrogen (N) and C concentrations as well as many other soil chemical [e.g., available phosphorus (P), pH, and other macro- and micronutrients) and physical (e.g., sand, silt and clay contents) properties.    C sequestration rates were also significantly different and ranged from 0.13 to 0.47 Mg C ha-1 yr-1. Many of the differences demonstrated relationships with the mineral make-up of the RM treatment. The SA mine soils also differed significantly in many properties after 29 years, including N, C, and many other nutrient concentrations and contents. C sequestration rates were also significantly different with the SD and 224B treatments having negative sequestration rates, and the remaining treatments ranging from 0.23 to 0.80 Mg C ha-1 yr-1. Collectively, the results demonstrate that topsoil substitutes and surface amendments show divergent trends in soil C and nutrient dynamics after nearly three decades of development and stress the importance of post- mining reclamation based on available materials and reclamation goals. / Master of Science
62

Site Quality Classification for Mapping Forest Productivity Potential on Mine Soils in the Appalachian Coalfield Region

Jones, Andy Thomas 11 August 2005 (has links)
Surface mining for coal in the Appalachian region destroys native forests and replaces them with reclaimed landscapes that are often revegetated as grasslands and are unacceptable for managed forest production without extensive remediation. Tree survival and growth are dependent on many reclaimed mine land properties. However, conventional mapping techniques using USDA soil series does not identify these critical soil property differences. This study was conducted to create a forest site quality classification system to be used to evaluate the potential productivity of specific tree species on mine soils. High soil bulk density is the most common limitation on mine soils and methods to efficiently measure this property were evaluated. No valid quantitative method of measuring mine soil bulk density was found due to the high rock fragment content in the soil profile, but a method for estimating relative soil density class was developed. Other soil chemical and physical properties were analyzed at abandoned mine sites in Virginia, West Virginia, and Ohio. Mine soil properties differed throughout the Appalachian region, with Ohio sites having finer textures and less rock fragments, West Virginia sites having coarser textures and a high quantity of dark-colored shale, and Virginia sites dominated by sandstone rock types. Selected field-measured soil and site properties were regressed with site index (SI) base age 50 at 52 sample locations in 10- to 18-year old white pine (Pinus strobus L.) stands on reclaimed mine lands. Sufficiency curves for nine soil and site properties were produced and a general productivity index (PI) calculated. Regression of the general PI and measured SI of white pine produced an R2 of 0.61. The general PI was simplified to four soil properties (soil density, rooting depth, texture, and pH) most significantly related to the SI of white pine, and the properties were weighted based on their importance to white pine growth on mine soils. The modified PI model produced an R2 of 0.69 for a linear relationship between PI and measured SI. The SI values were divided into five classes of equal interval and the corresponding PI values were used to define five forest site quality classes that could be identified by measuring and mapping differences in the PI on older mine soils. The model may be modified for determination of hardwood productivity after validation sites are located. Soil and site properties that are correlated with seedling survival appear different than those properties important for tree productivity. The forest site quality classification system proposed here proved practical for mapping a selected mine site, and the maps may be used as a validation test after future reforestation. / Master of Science
63

Managing symbiotically-fixed nitrogen on mined land for tree crops

Brown, Sarah K. 10 November 2009 (has links)
Young mine soils constructed following surface-mining for coal contain low levels of organic matter and nitrogen. It was hypothesized that nitrogen-fixing plants could be incorporated into a reforestation system in a manner that would meet the short term and long-term nitrogen needs of crop trees while rebuilding the soil and litter nitrogen pools and restoring a stable nitrogen cycle. The nitrogen status of two interplanting studies containing legume ground covers was examined. The first study site was mined prior to 1940 and subsequently abandoned. In 1988, the land was reclaimed, and an interplanting study was established in 1990. Pitch x loblolly pines (Pinus x rigitaeda) and eastern white pines (Pinus strobus L.) were interplanted with four nitrogen-fixing species: black alder (Alnus glutinosa L. IGaertn.l), black locust (Robinia pseudoacacia L.}, bicolor lespedeza (Lespedeza bicolor) and autumn olive (Elaeagnus umbel/ata Thwnb.). Pitch x loblolly pine survival was good; however, eastern white pine survival was only fair, averaging 54%. All of the nurse tree species with the exception of black alder had fair survival rates. Black alder survival was extremely low at 19%. After the third growing season, a ground cover dominated by legumes averaged 79% cover. The black mine spoil on the site was extremely rich in nitrogen, averaging 5,115 mg·kg-1. When the black mine spoil was mixed with the native topsoil, a mine soil that was created had an extremely variable total nitrogen content. However, low mineralizeable nitrogen levels suggested that the nitrogen in the mine spoil was not generally available. Pine responses to the four nitrogen-fixing species were compared. Nurse trees had no effect on pine growth after three years. Pine foliar nitrogen levels were adequate across the study site even in the control treatments and in the microsites where few legumes were present. Microsites surrounding 50 pines of each species were studied. The pitch x loblolly pines grew larger at lower pH levels and higher coarse fragment content reflecting the pines' preference for moderately acid soils, coarse-textured soils. Some competition was present between the crop trees and herbaceous cover, but it was not a controlling factor in pine tree growth. / Master of Science
64

Costs of Reclamation on Southern Appalachian Coal Mines: A cost-effectiveness analysis for reforestation versus hayland/pasture reclamation

Baker, Katherine 03 September 2008 (has links)
The two most common options for post-mining land uses in the southern Appalachians are forestry or hayland/pasture. Hayland/pasture has become the predominant reclamation type due to ease of establishment and strict regulation standards requiring quick and dense erosion control by herbaceous cover. Recently, more landowners have become interested in returning mined land to an economically valuable post-mining land use, such as forestry. Landowners are becoming more aware of the possible future profits from timber stand harvests, as well as other benefits (monetary and aesthetic) derived from a forestry post-mining land use. Although hayland/pasture lands can provide economic returns through forage and grazing rents, many post-mining pasture lands are left fallow, with no economic returns being gained. Current research has provided the biological and technical information needed to reclaim mine lands to productive forest stands and achieve bond release. Cost information though has been lacking, or variable at best. The purpose of this study is to understand the processes of reclamation for both forestry and hayland/pasture, and calculate detailed cost estimates for both reclamation types. Total costs of reclamation are determined using a cost engineering method, in conjunction with Office of Surface Mining Regulation and Enforcement bond calculation worksheets. In Kentucky, Maryland, Pennsylvania, Tennessee, Virginia, and West Virginia, hayland/pasture reclamation is more costly on a per acre basis. The cost of hayland/pasture reclamation is greater than the cost of forestry reclamation by $140 per acre to $350 per acre. In Ohio, forestry reclamation is more expensive by nearly $60 per acre. Grading costs are four times as costly for hayland/pasture reclamation, as compared to forestry reclamation. Pasture reclamation requires more grading passes to prepare the seedbed, requiring four passes. Forestry reclamation typically involves only grading the site with one dozer pass to prevent compaction of minesoils which inhibits tree growth. Hyrdoseeding costs are also higher for hayland/pasture reclamation due to higher application rates of fertilizer and herbaceous seed. The hydroseeding costs make up the largest percentage of the total per acre cost for both forestry and hayland/pasture reclamation. Lime and mulch costs are equal for both reclamation types and are included in the hydroseeding equation. Due to the increased grading costs and higher hydroseeding costs, hayland/pasture reclamation is more expensive for all states analyzed in the Appalachians, other than Ohio. These cost estimates can provide useful tools for mine operators and landowners to determine the most economical and suitable post-mining land use for their individual property. / Master of Science
65

Conifer regeneration, understory vegetation and artificially topped conifer responses to alternative silvicultural treatments /

Huff, Tristan. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 73-77). Also available on the World Wide Web.
66

Policy learning and policy implementation in China: a case study of the Grain for Green project

Guo, Jia, 果佳 January 2010 (has links)
published_or_final_version / Politics and Public Administration / Doctoral / Doctor of Philosophy
67

Modélisation prospective et échelles spatiales en montagne : application aux Pyrénées françaises / Prospective modelling and spatial scales in mountainous areas : application to the French Pyrenees

Vacquié, Laure 03 June 2015 (has links)
Les espaces montagnards représentent des zones à forts enjeux environnementaux, économiques, sociaux voire culturels. Les changements d’occupation et d’usage du sol qui s’y tiennent, qu’ils soient d’origine anthropiques ou non, ont engendré, au cours des dernières décennies, des dynamiques significatives d’enfrichement et de reforestation dans les Pyrénées françaises. Les tendances en cours laissent présager que ces dynamiques vont s’amplifier à l’avenir. Si ces dynamiques sont étroitement liées au déclin des activités agro-sylvo-pastorales, la localisation des zones potentiellement concernées constitue un réel enjeu pour les gestionnaires et les acteurs locaux. Dans une perspective de gestion à moyen ou long terme des espaces montagnards, il est aujourd’hui essentiel de pouvoir leur fournir une vision quantifiée des futurs possibles de leur territoire afin d’éclairer leurs décisions. L’objectif de ce travail est de construire des scénarios prospectifs spatialisés à trois échelles différentes et emboîtées (régionale, locale et micro-locale) afin d’identifier les espaces les plus vulnérables aux changements d’occupation et d’usage du sol et d’analyser l’influence des échelles spatiales et des approches de modélisation sur leur localisation. La démarche méthodologique s’articule autour de quatre étapes. La première étape consiste à identifier les approches de modélisation prospective qui sont privilégiées selon les échelles spatiales considérées. La seconde étape vise à construire « la base » des scénarios. La troisième étape consiste à produire les scénarios prospectifs spatialisés à chacune des échelles spatiales, selon des démarches de modélisation adaptées et des facteurs explicatifs pertinents, afin de simuler l’évolution possibles des paysages montagnards et d’identifier les espaces les plus vulnérables aux processus d’enfrichement et de reforestation. Enfin, la dernière étape consiste à analyser l’influence des échelles et des approches de modélisation au sein des travaux de prospective. Les scénarios prospectifs spatialisés ont permis (i) de quantifier et de spatialiser les impacts possibles de contextes socio-économiques et environnementaux contrastés sur les changements d’occupation et d’usage du sol et (ii) d’identifier les espaces les plus vulnérables aux changements à chacune des échelles considérées. Le croisement des scénarios produits a également permis d’évaluer l’incertitude spatiale des changements liée au futur. Les modèles pattern-based, utilisés à l’échelle régionale et locale, tendent à sous-estimer les changements par rapport au modèle process-based appliqué à l’échelle micro-locale. Au final, l’approche multi-scalaire a permis : d’apporter des connaissances sur le fonctionnement du système pyrénéen, voire de combler des lacunes quant aux données disponibles, qu’une approche mono-scalaire n’aurait pas produites ; de cibler les espaces les plus propices aux changements et d’établir un degré de confiance quant aux approches de modélisation choisies dans le but d’éclairer les politiques et stratégies de gestion. / Mountain areas exhibit high environmental, economic, social or cultural values. Land use and cover changes (LUCC), whether or not from anthropogenic origin, have led to significant encroachment and reforestation dynamics over the last decades in the French Pyrenees. Current trends suggest that these dynamics will amplify in the future. If they are closely related to the decline of agropastoral and forestry activities, the location of potentially affected areas is of great importance for managers and local stakeholders. For medium to long-term management perspectives, it is now essential to provide a quantified vision of possible futures of their territory to help in the definition of sustainable strategies. The objective of this work is to spatialize future scenarios at three different scales (regional, local and micro-local) to identify the most vulnerable areas to LUCC and analyze the influence of spatial scales and modeling approaches on their location. The methodology is based on four stages. The first step is to identify prospective modelling approaches that are preferred according to the considered spatial scales. The second step is to provide the knowledge for building scenarios. The third step is to simulate future scenarios at each spatial scales to identify the most vulnerable areas to encroachment and reforestation. The last step is to analyze the influence of scales and modeling approaches in the prospective framework. Spatially explicit scenarios allow to (i) quantify and assess possible impacts of contrasting socio-economic and environmental contexts on LUCC, and (ii) identify the most vulnerable areas to encroachment and reforestation for each considered spatial scale. Moreover, the combination of scenarios allows to evaluate the spatial uncertainty, regrouping the inherent and the ensemble uncertainties, related to future LUCC. The pattern-based models used at the regional and local levels tend to underestimate LUCC compared to the process-based model used. Finally, the multi-scale approach allowed to provide knowledge on the Pyrenean land system that a single scale approach would not have provided, to target the areas at stake regarding future LUCC and to establish a degree of confidence in the adopted modeling approaches in order to help in the definition and assessment of land use policies and strategies.
68

Reforester les tropiques semi-arides ? : Enjeux, contraintes et opportunités climatiques dans la perspective du changement global / Reforesting semi-arid tropics ? : Objectives, constraints and climatic opportunities in the context of global change.

Rajaud, Amélie 26 September 2016 (has links)
De nombreux projets de protection et de reforestation sont mis en place à l'échelle internationale pour enrayer la déforestation croissante. L'objectif de ce travail de thèse est de mieux caractériser les contraintes et les opportunités de projets de reboisement, pour les régions tropicales semi-arides, particulièrement vulnérables, dans le contexte duchangement climatique global. La revue de littérature (chapitre 1) confirme que les projets de reforestation ayant vocation à atténuer le réchauffement climatique ont plus de chances de réussite sous les latitudes tropicales, où les différents effets de la végétation sur le climat convergent dans ce sens. Entreprise pour satisfaire divers services écosystémiques, la reforestation dans les zones tropicales semi-arides est ainsi porteuse d'effets bénéfiques tant globalement que localement. Cependant, dans ce contexte très limité en eau, l'implantation d'un couvert arboré trop dense pourrait avoir des effets opposés à ceux recherchés à long terme. Dans le chapitre 2, une approche «bioclimatique » est appliquée à un ensemble multi-modèle de projections, pour suivre l'évolution du domaine tropicalsemi-aride global sous l'effet de plusieurs scénarios (RCP) de changement climatique. Ce domaine se maintient en majeure partie dans les conditions futures. Une certaine proportion évolue toutefois vers des conditions soit plus arides (jusqu'à +25% du domaine global) soit plus humides (jusqu'à 11%). Malgré cela, le domaine étudié s'accroît entre ledébut et la fin du 21e siècle, jusqu'à 13% en moyenne (RCP 8.5). Ceci résulte d'un élargissement progressif en-dehors de la ceinture tropicale, corrélé avec le réchauffement global, et cohérent avec l'hypothèse d'un élargissement de la circulation de Hadley. La méthodologie proposée au chapitre 3 a pour objectif d'analyser les implications de cetteévolution sur le potentiel climatique de maintien d'un couvert arboré. L'utilisation d'un modèle global de végétation (ORCHIDEE, développé à l'IPSL) pour simuler ce potentiel permet de prendre en compte de manière mécaniste les facteurs climatiques de la croissance des plantes. Une typologie des profils de résultats délimite des sous-régionscaractérisées chacune par une relation distincte du développement des arbres à la densité du couvert. Les cinq "régimes" de la typologie sont ainsi classés du plus défavorable (régime 1) au plus favorable (régime 5). L'expérience de référence est réalisée à partir de données d'observation (CRU). Le régime 1, caractérisé par l'absence de maintiend'un couvert pour les plus hautes densités arborées, occupe près de la moitié du domaine étudié. Le second régime le plus représenté est le régime 4 (28% du domaine). Plus favorable, il est défini par un développement des arbres élevé, sans être maximal, pour toutes les densités arborées. Le potentiel arboré de chaque régime est caractérisé par sonoptimum : fraction arborée réalisant le meilleur compromis entre productivité du peuplement et développement des arbres. L'application de cette méthodologie à des projections climatiques futures, pour le RCP 8.5, fait l'objet du chapitre 4. Le modèle ORCHIDEE est forcé avec des sorties de modèles de climat, pour le début et la fin du 21esiècle. A la fin du siècle, le régime 1 ne représente plus que 25% du domaine total, en moyenne, tandis que le régime 4 devient prépondérant (49% du domaine). La stabilité du potentiel arboré intrinsèque à chaque régime permet d'interpréter une évolution vers un régime plus ou moins favorable comme une augmentation ou une diminution de cepotentiel. Or celui ne subit pas la diminution générale que l'augmentation de l'aridité laissait présager. Une expérience complémentaire montre que la raison en tient principalement à l'effet de fertilisation du CO2 atmosphérique. L'interprétation de ces résultats montre ainsi que les zones du domaine tropical semi-aride dans lesquelles unereforestation serait à déconseiller sont assez peu étendues. / In the face of evergrowing global deforestation, numerous forest protection and restoration projects have been deployed at the international scale. The goal of this thesis is to provide adaptation planning in the vulnerable tropical semi-arid regions with scientific material about reforestation project constraints and opportunities at the global scale, inthe context of climate change. The literature review (chapter 1) confirms that reforestation projects aimed at warmingmitigation hold a better chance of success under tropical lattitudes. Indeed, both biochemical and biophysical effects of the vegetation on climate converge toward a global cooling effect. As reforestation in tropical semi-arid regions aims at satisfying various ecosystemic services, it holds beneficial promises at both the global and the local scale. However, due to scarce water resources, implementing a tree cover in semi-arid conditions could turn out unsustainable in the long run. A bioclimatological is applied, in chapter 2, to a multimodel ensemble of projections in order to draw the evolution of global tropical semi-arid territory under several climate change scenarios (RCP). The present tropical semi-arid territory is expected to remain mostly so in future conditions. However, up to 25% of the this territory on average will evolve towards arider conditions, and up to 11% towards wetter conditions. Nevertheless, the tropical semi-arid territory will increase by the end of the 21st century, by up to 13% on average (RCP 8.5). This increase results from a migration outside of the tropical belt, consistent with the Hadley circulation widening hypothesis under climate change. Chapter 3 proposes a methodology aimed at analysing the implications of this evolution for the climatic potential of tree cover sustainability. The global vegetation model (ORCHIDEE, developed at IPSL), used to simulate this potential, accounts mechanistically for all the climatic factors of the plant's growth. A typology of result profiles from the simulation experiments partitions the territory into subregions characterized by a specific relation between the tree development and the tree cover density: five types range from the least (Type 1) to the most (Type 4) favourable ones. A reference experiment is performed using observational climate data (from the Climatic Research Unit). Covering almost half of the territory, Type 1 is characterized by the impossibility to maintain a tree cover for the highest cover densities. The second type in order of surface occupation is Type 4 (28% of the territory). More favourable, it is characterized by high tree development for any tree cover density. The "tree cover potential" of each type is characterized by its optimum: the tree cover density that realises the best compromise between tree development and total productivity. In Chapter 4, the same methodology is applied to future climate projections for RCP 8.5. The ORCHIDEE model is thus forced with global climate model outputs, for the beginning and the end of the 21st century. By the end of the century, Type 1 represents no more than 25% of the tropical semi-arid territory on average, while Type 4 becomes the dominant one (49% of the territory). Because of the stability of the tree cover potential whithin each type, the evolution toward a more or less favourable type can be directly interpreted in terms of an increasing or a decreasing potential. The results show that the tree cover potential in the tropical semi-arid territory does not systematically suffer from the general decrease that could be expected from increasing aridity. A complementary experiment suggests that the main reason for this result lies is the atmospheric CO2 fertilization effect. Interpreting these results for reforestation strategy recommandations, suggests that, for the long term, areas of the tropical semi-arid territory where reforestation would be advised against are overall relatively small.
69

Les causes proximales du ralentissement de la déforestation en Thaïlande

Leblond, Jean-Philippe January 2004 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
70

Reflorestamento no Brasil e o Protocolo de Quioto / Reforestation in Brazil and the Kioto Protocol

Scarpinella, Gustavo D'Almeida 24 June 2002 (has links)
A questão das mudanças climáticas vem ganhando destaque e sendo mais discutida à medida que se caminha para a ratificação do Protocolo de Quioto. No presente trabalho é analisada a viabilidade de um projeto de reflorestamento candidato ao Mecanismo de Desenvolvimento Limpo, mecanismo de flexibilização proposto pelo Protocolo que permite a participação brasileira. São discutidos aspectos favoráveis e desfavoráveis à implementação de um projeto florestal, nas condições atuais. Para tal discussão propõe-se uma atividade de reflorestamento com espécies do gênero Eucalyptus, administrada por uma cooperativa florestal dentro da regional agrícola de Botucatu (SP). Os objetivos principais desta atividade são a obtenção de madeira para fins de serraria e a comercialização de créditos de carbono referentes ao volume de madeira serrada. Foram feitos cálculos de viabilidade econômica pela Taxa Interna de Retorno (TIR) e pelo Valor Presente Líquido (VPL) do projeto, com e sem o emprego do MDL. Verificou-se a viabilidade econômica nos dois casos, embora a diferença na receita não tenha sido considerável. Em projetos em que não há a participação do MDL, a TIR média foi de 7% para todas as áreas. Com a participação do MDL, houve uma variação da TIR de 6,2% a 7,3%, conforme as extensões das áreas adotadas e os preços pagos pela tonelada do carbono. Para pequenas áreas, o emprego do MDL pode inviabilizar o projeto. As atividades florestais para fins de serraria mostraram um rendimento muito baixo para o MDL, pelo fato de apenas um décimo da produção total ser aceito para comercialização dos créditos de carbono. / The issue of climate change wins relevance and brings controversy as the ratification of Kyoto Protocol approaches for most countries. Present work analyses feasibility for a reforesting project candidate for the Clean Development Mechanism (CDM). CDM is a flexibilization mechanism proposed in the Protocol wich allows Brazilian participation. Both favorable and unfavorable aspects are discussed for the implementation of a forest project under present conditions. For the purpose of this discussion, an activity of reforestation based on trees of the Eucalyptus species, managed by a forest cooperative society, in the agricultural region of Botucatu (SP). Main goal for such cooperative are obtained of lumber and commercialization of carbon credits relative to the quantity of lumber produced. Calculations for economic feasibility were carried out, producing the Internal Rate of Revenue (IRR) and the Present Net Worth (PNW), both under and out of the CDM. Economical feasibility were confirmed for both cases, although difference between revenues was not considerable. For projects with no CDM participation, average IRR was 7,0 per cent for all area extents. With CDM participation, the was a rate range between 6,2 and 7,3 per cent, according to the extent of submitted areas, and prices paid for ton of carbon. For small areas, CDM adoption can turn the project unfeasible. Forest activities for producing lumber showed low profitability for CDM, due to the fact that only one tenth of total production is accepted for commercialization of carbon credits.

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