Renewable energy has been developing rapidly in the U.S. over the past decades. This thesis first reviewed the status, challenges, and government policies related to the development of bioenergy products from forest-derived woody biomass. Forest management alternatives of loblolly pine (Pinus taeda) plantations for producing both timber and biofuels were then evaluated using economic and biological criteria. The PTAEDA3.1 computerized yield simulator was used to predict growth effects of various site preparation techniques, initial planting densities, and thinning activity. Results indicated that on Site Index 50 to 70 lands, the average annual yields of stem residues ranged from 0.86 to 1.20 tons per acre, from which 39.8 to 47.4 gallons of ethanol could be produced. The rise of relative biomass price would increase wood availability for biofuels. It will also boost intensive management practices, such as intensive site preparation, closer initial planting spacing, earlier thinnings and a shorter harvesting age.

This thesis deals with perceptions of refuse as an asset or as a liability and the questions of waste management practices. The aim has been to gain new insights into Stockholm’s waste management in the period 1900–1975 by studying change and continuity in municipal practices and the notions that governed the municipal actors’ actions. The central questions are what factors determined the city’s waste management, and how an urban and local (environmental) problem was formulated and addressed by local authorities and political bodies. In answering, I have applied a theory of inertia in large technical–administrative systems and an analytical framework based on the concept of waste management regimes. During the period a resource recovery regime was replaced by an incineration regime. At the turn of the last century, the quantity and type of refuse produced by Stockholm’s rising population was compounded by increasing consumption. In order to modernize the capital’s waste disposal the city invested in resource recovery by introducing source separation. The fall in demand for fertilizer and a changing composition of the waste in the 1920s made it more difficult to get rid of refuse and led to an end of waste separation. Incineration came to be seen as the modern option and in 1938 Sweden’s first modern incineration plant for municipal waste was built outside Stockholm. The amount of waste produced by Stockholm nearly tripled between 1922, when it was at its lowest levels, and the mid-1960s. The late 1960s saw an even more dramatic increase. In the 1960s waste was discussed as an important environmental issue and in the 1970s recycling was implemented in small scale. At the national level recycling was adopted as a waste management aim in 1975.

Le but de cette thèse était de comprendre les liens entre deux processus de dégradation de la matière organique : la digestibilité du fourrage par les herbivores domestiques et la décomposabilité de la litière par la microfaune du sol. Nous avons fait les hypothèses suivantes : (i) les pratiques de gestion affectent la digestibilité et la décomposabilité des espèces, et (ii) en accord avec l’hypothèse de dominance, celles des communautés via des changements de leur structure fonctionnelle ; (iii) digestibilité et décomposabilité peuvent être estimées par un même « marqueur fonctionnel » facile à mesurer aux niveaux d’organisation de l’espèce et de la communauté. Ce travail a été réalisé dans des parcours du domaine expérimental de La Fage situés sur le Causse du Larzac (Aveyron). Nos résultats ont montré un effet des pratiques de gestion sur la digestibilité et la décomposabilité des différents organes (feuille, tige, partie reproductrice) : les espèces de parcours pâturés et fertilisés ont présenté une digestibilité et décomposabilité supérieures à celles des espèces de parcours uniquement pâturés. Des mesures effectuées à deux dates de récolte ont permis de mettre en évidence une baisse de digestibilité au cours du printemps dans les différents organes, principalement causée par une augmentation de leur teneur en fibre. Une relation positive entre digestibilité et décomposabilité a été montrée pour les feuilles et les tiges dans les deux types de parcours. Cette relation était fortement dépendante de la teneur en fibres des organes, qui peut être estimée de façon fiable par la teneur en matière sèche de ceux-ci : plus la teneur en fibres était élevée, plus la teneur en matière sèche était forte, induisant une faible digestibilité et une faible décomposabilité. Ces résultats ont également été démontrés à l’échelle des communautés pour la digestibilité et la décomposabilité, confirmant l’hypothèse de dominance : les propriétés des écosystèmes peuvent être prédites à partir de traits des espèces dominantes des différents parcours, et en particulier de leur teneur en matière sèche. La teneur en matière sèche est donc un marqueur puissant et facile à mesurer pour estimer la digestibilité et la décomposabilité de systèmes complexes. L’approche fonctionnelle de la diversité biologique basée sur les traits peut donc être utilisée comme un outil de diagnostic du fonctionnement des prairies permanentes afin d’adapter les pratiques de gestion selon les objectifs des éleveurs. / The aim of this thesis was to understand links between two degradation processes of organic matter: the forage digestibility by domestic herbivores and the decomposability of litter by soil microfauna. We hypothesized that: (i) management regimes influenced species digestibility and decomposability, and (ii) in agreement with the dominance hypothesis, those of communities through changes in their functional structure; (iii) digestibility and decomposability can be estimated by the same “functional marker” both at the species and community levels. This study was conducted in rangelands from the La Fage research station located on the Larzac Causse (Aveyron). Our results showed an effect of management regimes on the digestibility and decomposability of different organs (leaf, stem, reproductive part): species from grazed and fertilized grasslands had higher digestibility and decomposability than those from grasslands solely grazed. Measurements conducted at two harvest dates showed a decrease of digestibility of the different organs during spring, mostly due to an increase in fibre concentration. A positive relationship between digestibility and decomposability was found for leaves and stems in both management regimes. This relationship was strongly dependent on organ fibre content, which could be safely estimated by the dry matter content of these different organs: the higher their concentration in structural tissues, the higher their dry matter content, and the lower their digestibility and decomposability. These results were also found at the community level for both properties, thereby validating the dominance hypothesis: the digestibility and decomposability of communities could be predicted from the traits of dominant species found in each management regime, in particular their dry matter content. Dry matter content therefore appears as a powerful and easy to measure marker to estimate the digestibility and decomposability of complex systems. The trait-based approach to plant functional diversity can be used as a diagnostic tool to assess rangeland functioning, so as to modulate management practices according to farmer’s objectives.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work was developed with the aim of studying the efficiency of the models that express the relationship of density and diameter in evenaged stands of Pinus taeda L., managed in full density and highly stocked for a bioeconomic model of production. For this, were tested density and diameter models, using data derived from 50 permanent plots, measured annually until 18 age, allocated to settlements established in the spacing of 1.5x1.0 m, 2.5x 1.0 m, 1.5x2.0 m, 2.0x2.0 m, 1.5x3.0 m, 2.5x2.0 m, 2.0x3.0 m and 2.5x3.0 m, kept at full density, in Otacílio Costa, physiographic region of Santa Catarina State plateau.The results of the bioeconomic modeling of production, based on the density management diagram system for tall trees, we concluded that the models proposed by Reineke, Yoda, Zeide and Tang showed a good statistical precision, with a determination coefficient higher than 0,88 and coefficient of variation less than 1.25 % but the model of Tang was more accurate and efficient. The size of the diameter at the point where you start self-thinning in the population varies considerably with the density of trees established per hectare. For all plant spacings analyzed did not prove the value of the slope of -3/2 law of self-thinning proposed by Tang and is a result of the initial spacing. The limit of self-thinning in less dense populations, occurs with a diameter slightly less than in maximum density, which is directly proportional to the density of trees when the implementation of the forest. The model of self-thinning described the management zones of great individuals in the population, between 0.45 and 0.55 limits the maximum density of the forest. The annual increment in diameter between 6 and 7 years, when related to relative density (G/d0,5622) identified five areas of growth, defined by: excessive space - trees grow free of competition;free growth - where growth in diameter is maximum; increased competition- when the diameter increment begins to decrease; full density - when productivity of the stand is maximum; and imminent death - begins when individuals have died by excessive density and high competition. The Diagrams Density Management of the variables mean diameter, basal area, volume by the Population Density Index was efficient and to estimate thisis values with accuracy, showed an efficiency of 0.99. The lines demarcating the areas of competition allow us to project the trajectory of the diameter and density, with the definition of the clearcutting. The Normal, Lnnormal, Weibull and Gamma probability distributions, described accurately the variation of the density of the stands, but the Weibull function with two parameters was comparable to the adjustment by the simplicity and efficiency in the prognosis of frequencies for diameter in time. The shape of the trunk was adjusted by the polynomial of five degree, allowed the best estimates than other models. The net present value of R$ 15587.60 ha-1 was given to the management regime with three thinnings at 9, 13 and 18 years and cut at 22 years, higher than the other schemes simulated. A comparison of management regimes for the equivalence of planning horizons for 28 years, determined by the equivalent annual value, said the management regime with three thinned and cut at 22 years, such as greater economic efficiency, with a value of R$ 1380.10 ha-1. The internal rate of return in any simulated management regimes was highly attractive, with varying from 14.83 % per year in managed regimes stands with three thinning and cut to 22 years to 14.25 % per year in managed regimes stands with threethinning and cut to 18 years. The biggest benefit/costs ratio was 2.81, obtained in the management regime with three thinnings, at 9, 13 and 18 years and final cutting at 22 years. / Este trabalho foi desenvolvido com o objetivo de estudar a eficiência dos modelos que expressam a relação de densidade e diâmetro em povoamentos equiâneos de Pinus taeda L., manejados em densidade completa e altamente estocados, para obtenção de um modelo bioeconômico da produção. Para isso, foram testados modelos de densidadee diâmetro, através de dados originados de 50 parcelas permanentes, medidas anualmente até os 18 anos, alocados em povoamentos implantados em espaçamentos de 1,5x1,0 m, 2,5x1,0 m, 1,5x2,0 m, 2,0x2,0 m, 1,5x3,0 m, 2,5x2,0 m, 2,0x3,0 m e 2,5x3,0 m, mantidos em densidade completa, em Otacílio Costa, região fisiográfica do planalto do estado de Santa Catarina. Os resultados obtidos da modelagem bioeconômica da produção, baseada no Diagrama de Manejo da Densidade para sistema de alto fuste, permitiram concluir que os modelos propostos por Reineke, Yoda, Zeide e Tang apresentaram uma boa precisão estatística, com um coeficiente de determinação superior a 0,88 e um coeficiente de variação inferior a 1,25%, porém o modelo de Tang mostrou-se mais preciso e eficiente. A dimensão do diâmetro médio no ponto em que inicia o autodesbaste na população varia consideravelmente com a densidade de árvores implantadas por hectare. Para todos os espaçamentos de plantio analisados, não se comprovou o valor do coeficiente angular de -3/2 da lei de autodesbaste proposto por Tang, sendo uma decorrência do espaçamento inicial. O limite de autodesbaste de populações menos densas ocorre com um diâmetro médio pouco inferior ao obtido em máxima densidade, sendo este diretamente proporcional à densidade de árvores quando da implantação da floresta. O modelo de autodesbaste descreveu as zonas de manejo ótimo dos indivíduos na população entre limites de 0,45 e 0,55 da densidade máxima da floresta. O incremento corrente anual em diâmetro entre o 6º e o 7º ano, quando relacionado com a densidade relativa (G/d0,5622), permitiu identificar cinco zonas de crescimento, definidas por: espaço excessivo as árvores crescem livre de concorrência; crescimento livre o incremento em diâmetro é máximo; aumento da competição o incremento em diâmetro começa a diminuir; estoque completo a produtividade do povoamento é máxima; e iminente mortalidade começa a haver morte de indivíduos por densidade excessiva e alta concorrência. Os Diagramas de Manejo da Densidade com as variáveis diâmetro médio, área basal e volume por Índice de Densidade do Povoamento foram eficientes e permitiram estimar estes valores com acurácia, para uma eficiência igual a 0,99. As linhas que delimitam as zonas de concorrência permitem projetar a trajetória do diâmetro por densidade populacional, com definição da idade de corte final. As distribuições de probabilidade Normal, Ln-normal, Weibull e Gama descreveram com acurácia a variação da densidade dos povoamentos, masa função de Weibull, com dois parâmetros, foi compatível pela simplicidade ao ajuste e à eficiência na prognose das frequências por diâmetro no tempo. A forma de tronco ajustada pelo polinômio do 5º grau apresentou melhores estimativas que outros modelos. O Valor Presente Líquido de R$ 15.587,60 ha-1 foi determinado para o regime de manejo com três desbastes, aos 9, 13 e 18 anos e corte final aos 22, superior aos demais regimes simulados. A comparação dos regimes de manejo pela equivalência dos horizontes de planejamento em 28 anos, determinado pelo Valor Anual Equivalente, indicou o regime de manejo com três desbastes e corte final aos 22 anos como o de maior eficiência econômica, com um valor de R$ 1.380,10 ha-1. A taxa interna de retorno em qualquer dos regimes de manejo simulados foi altamente atrativa, tendo variado de 14,83 % a.a. em povoamentos manejados com três desbastes e corte final aos 22 anos a 14,25 % a.a. em povoamentos manejadoscom dois desbastes e corte final aos 18 anos. A maior razão benefício sobre os custos foi de 2,81, obtida no regime de manejo com três desbastes, aos 9, 13 e 18 anos e corte final aos 22.

This paper examines the extent to which the economic gains derived from gum and resin commercialization impact rural livelihood improvement under different resource management regimes in the drylands of Ethiopia and Sudan. Primary data were collected through semi-structured interviews with 240 randomly selected small-scale producers in four regions with gradients of resource management regimes. The survey was supplemented by secondary data, group discussions and key informant interviews. In the four regions, gum and resin income contributes to 14%–23% of the small-scale producers’ household income. Absolute income was positively correlated with resource management regime and commercialization level. It was higher from cultivated resources on private lands, followed by regulated access to wild resources. In open-access resources, the producers’ income was the lowest, although accessed by the poor and women. However, dependence on gum and resin was higher in open-access resource areas. Households’ socioeconomic characteristics, resource access, production and marketing variables determining income from gum and resin were identified and their variation across the cases is discussed. Overall, gum and resin commercialization in the study areas play a potential poverty alleviation role as a source of regular income, a safety net, and a means of helping producers move out of poverty.

Many social workers that are working within the current healthcare system, feel that their profession is being marginalized, and they are worried that the social perspective might be lost, which would affect both the healthcare system and the patient in an undesirable way. This is a situation that is described by the social workers that were interviewed for the work of this assay. There is a proposition about a special legitimisation for social workers within the healthcare system. The main aim of this proposition is to secure the patient safety.  A second aim is to secure that the social perspective will remain with in the healthcare system.   The governance of the public sector of today, focuses on increasing the efficiency by control and review of measurable goals, which has affected the professionals' use of their skills and lead to de-professionalization. In today's knowledge management, measurable treatment through manuals is seemingly more important than professional competence, which has weakened the curators' profession role in healthcare. This picture is clearly stated in this essay's empirical study and is confirmed by the literature studied.   The trust delegation has the task to develop a reform that will better use the employees' skills so that the Swedish citizens receive their needed services through trust-based governance. The proposed introduction of legitimisation and the work of the trust delegation can both lead to changes for the social workers and the social perspective. For the social workers, the proposal raises hope. A legitimisation might strengthen their occupational role and at the same time indicate that the social perspective in healthcare is a specific and necessary area, which can lead to the development of the profession's jurisdiction.

This paper examines the extent to which the economic gains derived from gum and resin commercialization impact rural livelihood improvement under different resource management regimes in the drylands of Ethiopia and Sudan. Primary data were collected through semi-structured interviews with 240 randomly selected small-scale producers in four regions with gradients of resource management regimes. The survey was supplemented by secondary data, group discussions and key informant interviews. In the four regions, gum and resin income contributes to 14%–23% of the small-scale producers’ household income. Absolute income was positively correlated with resource management regime and commercialization level. It was higher from cultivated resources on private lands, followed by regulated access to wild resources. In open-access resources, the producers’ income was the lowest, although accessed by the poor and women. However, dependence on gum and resin was higher in open-access resource areas. Households’ socioeconomic characteristics, resource access, production and marketing variables determining income from gum and resin were identified and their variation across the cases is discussed. Overall, gum and resin commercialization in the study areas play a potential poverty alleviation role as a source of regular income, a safety net, and a means of helping producers move out of poverty.