Dissertations / Theses on the topic 'Tree tenure'

The management and utilisation of resources in agroforestry systems are influenced by both land and tree tenure systems, especially where land and tree tenure are distinct, and rights to one do not necessarily lead to rights over the other. Most academic research has examined the impact of land tenure on management and productivity in these landscapes. This thesis investigates the impact of tree tenure alongside other socioeconomic factors through the research question: 'how do local institutional arrangements affect the management, utilisation and ecology of indigenous economic trees in agroforestry parklands?' Shea and locust bean trees, two of the most economically, culturally and ecologically important indigenous agroforestry species in Northern Ghana, are chosen for the case study. This multidisciplinary study utilises several methodologies of data collection and analysis to assess individual and household behaviour in the management of shea and locust bean trees, and the impact on the ecology of these species. The analysis of incentives (and constraints) stemming from differing tenure arrangements reveals differing attitudes among the households to the preservation and planting of these trees on their farmlands. Women, who are primary gatherers of non-timber products from these trees and hence the main beneficiaries, have differing access to these trees, depending both upon the status of their household within the community and the tenure rules in place. Econometric modelling of shea and locust bean tree densities reveals the socioeconomic and institutional determinants of these tree densities on the farmland, highlighting the importance of economic and institutional incentives and constraints in shaping the management practices, and subsequently the ecology of these indigenous economic species. The findings demonstrate that the vagaries of the resource-use dynamics should be taken into consideration by any policy targeted towards promoting sustainable management and utilisation of these valuable parkland species.

Customary land ownership, recording and registration are complex issues in the Solomon Islands. At present, 87% of the land is held under customary laws. Almost all (some 99%) of the land held under customary law is not surveyed, recorded or registered to the tribes. Customary land disputes have been inhibiting rural development initiatives, which is partly responsible for the ill-being of the people. The Family Tree Approach (FTA) is a process being used within the To'abaita region of the Malaita Province to help address problems in the dilemmas of land ownership, land disputes, land recording, land registration and rural development in land held under customary laws in To’abaita. The FTA is a blend of indigenous epistemology, modern practices and Christian principles. Indigenously, the tribes identify with their land by tracing their origins through genealogies, historical narrations, tribal epics and chants, shrines and properties. Rev. Michael Maelia’u, a Church Minister and a former Parliamentarian, promotes the FTA. The FTA has four pillars (principles) – recognition, reconciliation, recording and registration – which are covered within five sequential phases. For instance, recognition is done in phase one of the process, enabling all members of a tribe to recognize each other. Reconciliation is part of the process, promoting forgiveness and acceptance of tribal members. Recording is an important pillar of the FTA, as its role is to produce documents that will be accepted by the law. Research results show that land registration is also a pillar of the FTA; once customary land is registered to the tribes, land disputes will be resolved, thereby enabling sustainable rural development that improves the people’s well-being. The FTA, however, is currently not formally recognized in the country. It has been used by 12 of approximately 20 tribes within the To'abaita region. Some of the To'abaita tribes have not adopted the FTA for various reasons. The FTA has enabled the disintegrated generations to recognize or identify with one another. It enables public recognition of existing tribes, tribal genealogies, tribal tales, tribal epics, the tribal iii shrines, and the tribal land. Reconciliation has been carried out at both intertribal and intra-tribal levels. The FTA enables identification of people who are residing on land and utilizing resources they do not have a right to. It makes people aware of their roots or the land of their origin, which would then lead to reduced land disputes that constrained development initiatives and the well-being of the people. The results, however, indicated that the FTA has problems either in the approach itself or in its management. It is incapable of achieving its objectives (reducing land disputes, enable rural development, enable tribal land registration, and resettling land that was wrongly acquired). People have split perception of the FTA and the legislation; this therefore reduces potential motivation that is needed to advance the approach. Results of the research also indicated that no proper and serious documentation has been done, despite knowing that it is one of the pillars. In To'abaita, gender and culture are contributing issues, which cause difficulties to the FTA. Also, the FTA lacked financial support. Those that have experience with the FTA believe that the FTA objectives need to be made known to promote motivation to the illiterate people of To'abaita. Adequate communication of issues to improve the FTA is essential. Forming a committee that oversees the design and management of the FTA is necessary for its improvement, and adequate financial support will bring the FTA forward. Chief empowerment by the legislation is essential to enable the FTA to achieve its objectives in the future.

My thesis consists of two interrelated projects. The first analyzes legal and aesthetic testimony in Atom Egoyan’s film The Sweet Hereafter. “But From My Lie This Did Come True” is an extended meditation on falling: literal accident, communal loss, ethical lapse, and imagistic and linguistic vertigo. Falling is this film’s instigating event, but falling is also a figure for trauma, and its capacity to make reference itself fall. By definition, a trauma exceeds our ability to contain and communicate what we have witnessed or survived. How then can it be possible to testify to a traumatic event and its effects? In dialogue with Paul de Man, Jean Luc Nancy, Sigmund Freud, and Cathy Caruth, I argue that The Sweet Hereafter reveals how one fall can powerfully reference another. My aim is not simply to apply theory to a film, but also to explore how the film reconfigures the theory. Just as Egoyan’s work adapts a novel to the cinema, my project adapts film to the essay form. The second part of my thesis excerpts Hook Tender, a novel inspired by archival research and oral history, including travels to BC logging camps and Canada’s Arctic. Hook Tender explores falling through the actual labour and visceral experience of felling trees. Set in an immigrant logging camp on Canada’s West Coast, the narrative also dramatizes falling in the ethical and psychological dimensions addressed in my essay. An accidental fall causes Eva to lose a child through still birth, and this loss instigates an emotional crisis and moral lapse as she begins an adulterous involvement with Charlie, an Inuit logger who communicates injustices survived by Indigenous communities. So both sections of my thesis offer a sustained reflection on falling: its broken narratives, questionable bearing of testimony, and the incalculable power of its emotional charge.

Les motets du XIIIe siècle chantés sur le répons Stirps Jesse forment l'apogée d'une tradition exégétique, iconographique et musicale plus connue sous le nom d'« arbre de Jessé ». Le répons, attribué à Fulbert de Chartres (mort en 1028), évoque de façon métaphorique les liens entre Marie et son Fils. Il rappelle ainsi un des fondements du dogme chrétien : l'Incarnation charnelle de Dieu par l'intermédiaire de la Vierge. Son utilisation dans les motets n'est donc pas anodine. Le Stirps Jesse, ou plus fréquemment la seconde partie de son verset FLOS FILIUS EJUS, a été repris et ordonné de façon rythmique pour servir à la création d'une polyphonie textuelle et musicale. La voix empruntée ou teneur détermine ainsi la mélodie, la longueur des phrases mélodiques et des vers du double. Pourtant, malgré ces contraintes et les nombreux contrafacta, l'étude démontre l'existence de liens structurels entre texte et musique dans les motets à deux voix sur FLOS FILIUS EJUS conservés dans le manuscrit W2. Les relations entre texte et musique reposent ainsi le plus souvent sur la coïncidence entre la disposition des poèmes et l'organisation des répétitions motiviques (colores), des registres et des rythmes
Thirteenth-Century motets composed on the response Stirps Jesse belong to a great exegetical, iconographical and musical tradition well-known as the « Tree of Jesse ». The response, which is possibly composed by Fulbert of Chartres (d. 1028), express the relationships between Mary and her Son. It calls to mind one of the most important Christian believes as the flesh Embodiment of God thanks to the Virgin which is one of the most important Christian dogmas. The Stirps Jesse, or more often the second part of the verse FLOS FILIUS EJUS, is rhythmically organized in order to create a textual and musical polyphony. The melody, the lengths of musical phrases and of the line of the upper part depend intimately on this quotation or tenor. Even if the tenor is of great influence on the polyphony, this study demonstrates that the textual structure of the upper part corresponds to the musical organization in the two-part motets on FLOS FILIUS EJUS in the manuscript W2. The relationships between poem and melody are built on the close connection between the structural organization of the text and of the melody thanks to the melodic patterns (colores), register and rhythms

Ce travail concerne les voies de biosynthese des acides gras a tres longue chaine (agtlc) specifiques de graines de limnanthes alba, une plante superieure interessant les industries oleo- et petro-chimiques. L'accumulation de ces agtlc, a savoir les acides 5-cis-eicosenoate, 13-cis-docosenoate et 5,13-cis-docosadienoate, dans les triacylglycerols (tag) implique la voie du glycerol-3-phosphate. De plus, cette synthese de tag apparait etre un evenement compartimente dans le temps chez l. Alba. Une etude des acyl-coa elongases, enzymes membranaires catalysant la biosynthese des agtlc, a ete entreprise dans les graines immatures de l. Alba. Deux systemes d'elongation distincts ont ete mis en evidence, l'un allongeant le stearyl-coa et l'autre allongeant l'oleoyl-coa. Ces activites d'elongation sont respectivement associees a des fractions subcellulaires sedimentant a 100. 000 g et 15. 000 g. La stearyl-coa elongase et l'oleoyl-coa elongase sont respectivement eluees d'une colonne de deae cellulose a des concentrations en nacl de 0. 35 et de 0. 20 m. Elles presentent respectivement des masses moleculaires apparentes de 300 et 250 kda et sont respectivement constituees de 3 (59, 62 et 75 kda) et de 2 sous-unites (59 et 75 kda). Ces deux systemes d'elongation sont localises dans des membranes differentes en ce qui concerne leur composition en acides gras. Parallelement, une variete de plantes de l. Alba, donnant des graines riches en huile, a ete isolee

Le dernier rapport du GIEC confirme clairement des projections climatiques prévoyant une augmentation des températures et de leur variabilité à la fin du XXIème siècle. Les effets de ces changements sur la production et la qualité des fruits ont été étudiés dans le cadre du projet CAQ40(INRA). Les expérimentations menées sur des pêchers en pot placés sous différents climats (témoin,+2°C et +5°C), ont permis d’identifier les processus (phénologie, développement, croissance,photosynthèse, métabolisme) les plus sensibles à l’élévation des températures et leurs conséquences sur le développement et la composition des fruits et la pérennité de la production.L’élévation de température a augmenté la demande climatique entraînant une diminution du potentiel hydrique des arbres, ce qui a pu entrainer une concentration des composés d’intérêt dans le fruit. La réduction du taux de photosynthèse des feuilles dans des conditions de forte température est liée à une inhibition de la photosynthèse par les températures élevées et à un contrôle stomatique lié au statut hydrique.Après floraison, l’élévation de température accélère la croissance végétative, induisant une mise en place de la surface foliaire anticipée. Cette croissance végétative précoce a eu pour conséquence (i) une dynamique très rapide d’élongation des axes en pousse longue (ii) une dominance apicale plus marquée, (iii) une diminution de la ramification des axes axillaires,contrairement aux traitements thermiques plus tardifs qui ont eu un effet défavorable sur l’initiation et la différenciation des bourgeons floraux réduisant le potentiel de production l’année suivante.En outre, l’augmentation de température après floraison a entraîné un raccourcissement très marqué de la durée de croissance du fruit, avec une date de récolte anticipée de près de 3semaines. Ce raccourcissement de la durée de croissance du fruit a entraîné une diminution du flux entrant de carbone dans le fruit, pénalisant sa croissance et sa qualité. Le climat très différent entre les deux années expérimentales a entrainé une forte variabilité de la composition des fruits entre les deux années d’expérimentation. En 2014, une élévation de température précoce ou continue a conduit à récolter des fruits de petites tailles ayant des concentrations et des teneurs en saccharose plus importantes. En 2015, la durée de développement entre floraison et maturité était encore plus courte qu’en 2014 ce qui pouvait être lié au climat plus chaud de 2015 et les fruits ont été moins sucrés et plus acides que ceux de 2014. Toutefois, l’élévation des températures en fin de développement en 2015 a augmenté les teneurs et les concentrations en hexoses et en sorbitol liées à un effet concentration mais également à un effet sur le métabolisme. L’élévation des températures en milieu et en fin de cycle a également favorisé l’accumulation d’acide malique et citrique. Les fortes températures n’ont pas eu beaucoup d’effet sur la vitamine C et ont soit augmenté ou diminué les teneurs en composés phénoliques. Les effets d’une élévation de la température sur le métabolisme sont donc très dépendants du stade de développement du fruit.L’utilisation de modèle à l’échelle du fruit (Virtual Fruit) et à l’échelle de l’arbre (QualiTree)pourrait permettre de simuler à la fois l’effet de l’environnement et des pratiques culturales sur la croissance et la qualité du fruit, et donner une vision plus intégrée du fonctionnement de la plante sous contraintes environnementales
The latest IPCC report clearly confirms the climate projections for increasing temperaturesand their variability at the end of the 21st century. The effects of climate changes in fruit yield andquality have been studied in a project funded by INRA (project CAQ40, Metaprogramme ACCAF).Experiments carried out on potted peaches placed in different climates (control, +2 ° C and + 5 ° C),allowed the identification of the processes (phenology, development, growth, photosynthesis,metabolism) most sensitive to rising temperatures and their consequences on the development andcomposition of fruits and the sustainability of production.Higher temperature has increased the demand for water, leading to a decrease in the waterpotential of the trees, which may have led to a concentration of the compounds of interest in thefruit. The reduction of leaf photosynthesis under high temperature conditions was related to theinhibition of photosynthesis by high temperatures and stomatal control related to water status.After flowering, the rise in temperature accelerates the vegetative growth, triggering a more rapidestablishment of leaf area. This early vegetative growth resulted in: (i) very rapid dynamics ofelongation of the axes in long shoot (ii) a more pronounced apical dominance, (iii) a decrease in theaxillary axial branching. In contrast the later heat treatment had an adverse effect on the initiationand differentiation of floral buds reducing the production potential in the following year.In addition, the increase in temperature after flowering resulted in a marked shortening ofthe fruit growth period, with an expected harvest date almost 3 weeks earlier. This shortening offruit growth duration has led to a decrease in the flow of carbon entering the fruit, penalizing itsgrowth and quality. The very different climates between the two experimental years resulted in ahigh variability in fruit composition between the two years of experimentation. In 2014, increasedtemperature during the early stage of fruit development or continuously led to the harvest ofsmaller fruit with higher concentrations and higher sucrose content. In 2015, the time durationbetween flowering and maturity was even shorter than in 2014, which could be linked to thewarmer climate of 2015. In 2015 fruits were less sweet and acidic than those of 2014. However, therise of temperatures at the end of fruit development in 2015 increased the levels andconcentrations of hexoses and sorbitol; this increase was partially due to a concentration effect butalso to an effect on fruit metabolism. Increased temperatures in the middle and at the end of fruitdevelopment also favoured the accumulation of malic and citric acid. The high temperatures did nothave much effect on vitamin C and either increased or decreased the levels of phenolic compounds.The effects of an increase in temperature on the metabolism are therefore very dependent on thestage of fruit development.The use of a Fruit‐scale model and a tree‐level (QualiTree) model could simulate both the effect ofthe environment and cultural practices on the growth and quality of the fruit, and give a moreintegrated view of the plant's functioning under environmental constraints

Le système racinaire, lien essentiel entre la plante et le sol quoi qu'essentiellement invisible, reste encore aujourd'hui peu étudié dans son ensemble. Les plantes étant ancrées au sol via leur système racinaire, leurs facultés d'adaptation et de survie sont donc très dépendantes de leurs capacités à savoir tirer profit de l'espace qui les entoure, notamment par l'intermédiaire de leur système racinaire. Certains arbres font néanmoins partie des plus grands et plus anciens êtres vivants de la planète, preuve s'il en est de leur capacité d'adaptation au milieu dans lequel ils poussent et aux changements environnementaux pouvant survenir dans le temps. Dans le cas des plantations, les contraintes anthropiques imposées se heurtent parfois aux limites de cette formidable capacité d'adaptation. Les travaux développés dans la première partie de cette thèse font l'objet de deux articles publiés et se concentrent sur une revue bibliographique des connaissances sur l'enracinement profond. Le rôle vital du système racinaire pour la plante est ainsi mis en avant ainsi que ses fonctions dans le continuum sol-plante-atmosphère. Son rôle essentiel, souvent sous-estimé dans le stockage du carbone, est également abordé. Les différentes techniques permettant d'accéder aux systèmes racinaires in situ sont passées en revue et nous présentons la technique du puits d'accès que nous avons utilisé pour observer les racines jusqu'à 5 mètres de profondeur. Nous avons également développé nos propres outils de prise de vue par l'intermédiaire de scanner à plat ainsi qu'un outil d'analyse d'images ( IJ_Rizo) aujourd'hui disponible en ligne.Dans la deuxième partie du mémoire, nous nous consacrons à l'étude du système racinaire de l'hévéa adulte (Hevea brasiliensis) dans le nord-est de la Thaïlande. Premier producteur mondial de caoutchouc naturel, la Thaïlande a fortement développé ses plantations d'hévéas allant jusqu'à étendre son exploitation au-delà de sa zone climatique naturelle, dans des zones à fortes contraintes hydriques. Dans ce contexte, nous avons étudié la saisonnalité et la dynamique des racines fines pendant trois ans ainsi que leur contribution au cycle du carbone. Nous avons pu mettre en évidence la continuité de la dynamique racinaire indépendamment des périodes de défoliation mais en lien avec la saisonnalité de la pluviométrie. Nous avons également pu caractériser la faible différenciation de la dynamique racinaire de 0 à 4,5 mètres de profondeur dans un tel contexte. La troisième partie de la thèse concerne l'étude du teck (tectona grandis), espèce endémique d'Asie du Sud-Est, et notamment du Laos dans la région de Luang Prabang. Le développement de sa culture sous forme de plantations mono-spécifiques se poursuit depuis les années 80. En appliquant la technique d'exclusion de pluie pendant 2 ans sur des arbres d'une plantation d'une vingtaine d'années, nous avons observé l'influence du régime de précipitations sur l'enracinement. Un arrêt pratiquement total de croissance des racines en surface et en profondeur a ainsi été mis en évidence. Nous concluons, dans le cas d'espèces à une forte dépendance à la ressource en eau de surface, à un impact direct sur l'état physiologique et une stagnation de la croissance des troncs. Certains individus ont démontré une capacité d'adaptation en modifiant leur cycle de foliation / défoliation accompagné d'une reprise de la croissance des troncs lors de la deuxième année du régime de sécheresse imposé. Nous avons également démontré l'importance de l'enracinement fin pour le stockage du carbone qui, dans ce contexte, représente plus de 45 % du carbone total, soit environ le double des données publiées dans la littérature.Les données obtenues pour les espèces étudiées dans ce mémoire pourront être utilisées pour la modélisation de scenarios simulant le changement climatique et le changement d'usage des terres
The root system is essential but essentially invisible. Plants are anchored to the soil through their root system; their adaptation and survival abilities are highly dependent on their ability to learn to take advantage of the space that surrounds them. Certain trees are nevertheless some of the largest and oldest living species on the planet- evidence of their ability to adapt to changes in their environment. Within managed anthropogenic constraints, particular species are vulnerable. It is clear that a wide range of parameters are likely to influence the root system and its operation, which offers many entry points to improve our understanding of a root's capacity for expansion, its dynamics, its role within the plant itself and within the soil plant atmosphere continuum. Available data on the extent and dynamics of plant roots includes several thousand references. However, the vast majority of these observations were made within the first meter of the soil profile. Data acquisition for the fine and/or deep roots is currently limited by constraints of time and financial resources. To overcome this lack of information, while trying to assess root dynamics under different environmental conditions, many models have been developed. However, it is still difficult to describe the complexity of root development in the community and to integrate its "plasticity".To understand such a complex environment, we must work toward establishing a definition of objectives and the tools necessary to develop and implement them. The work developed in the first part of this thesis is the subject of two articles and focuses on a literature review about deep roots. The vital role of the root system for the plant is well highlighted, as is its impact as a link within the atmosphere. We discuss the role of deep roots in carbon storage, which is critical and often underestimated. The different techniques for accessing the root systems in situ are also considered, and we present our access technique for observing the roots down to depths of five meters. We have also developed tools for shooting through a flatbed scanner and image analysis ( IJ_Rizo ) now available online.In the second part of the thesis, we focus on the study of root systems of adult rubber trees (Hevea brasiliensis L. RRIM 600) in the northeast of Thailand. Thailand has greatly expanded its acreage to extend its operations beyond its natural climate zone, into areas of high water stress. In this context, we studied the seasonality and dynamics of fine roots for three years and their contribution to the carbon cycle. We were able to highlight the continuity of root dynamics during independent periods of defoliation, yet link these to the seasonality of rainfall. We were also able to characterize the low differentiation of root dynamics at 0 to 4.5 m of depth in this context.The third part of the thesis concerns the study of teak particular to the region of Luang Prabang, Laos. By applying the rain exclusion technique for 2 years on a plantation of twenty-year-old trees, we observed the influence of precipitation patterns. During the period of water stress, an almost total cessation of root growth, at the surface and significant depths, has been highlighted. We conclude that in the case of species with a high dependence on water resources there is a direct impact on the physiological state and stagnated trunk growth. Some individuals have demonstrated an ability to adapt by changing their foliation/defoliation cycle, accompanied by a resumption of trunk growth during the second year of imposed drought. We also demonstrated the importance of rooting as a means of carbon storage, which in this context represents more than 45% of total carbon- roughly double the amount published in other literature .The data obtained for the species studied in this paper can be used for modelling scenarios simulating climate change and changing land use

L'atmosphère terrestre est le siège d'un transport de matière, en particulier d'éléments d'origines diverses, dont une proportion importante résulte des activités humaines. Ce phénomène induit des conséquences parfois graves, pour la santé humaine et pour la fonctionnalité des écosystèmes. Les éléments ainsi transférés sont redéposés, de manière complexe, à la surface de la terre, avec une cartographie de distribution très inégale, des possibilités d'accumulation, ou au contraire de dilution, variables, conduisant à des altérations diversifiées de la composition des eaux et des sols et de la fonctionnalité des êtres vivants. La redéposition atmosphérique est étudiée depuis une cinquantaine d'année sur les troncs des arbres, qui constituent une matrice verticale commune, très enrichie par l'apport atmosphérique, et pouvant mener soit à une analyse de composition, soit à des études de bioindication. Il en a découlé des tests de routine largement utilisés. Cependant, pour définir avec précision les apports d'origine anthropique et mieux maîtriser, en vue de les réduire, les apports anormaux ou dangereux, une étude en profondeur de cette déposition corticale devait être entreprise. C'est l'objet de ce mémoire. Au regard de la complexité du problème abordé, nous nous sommes essentiellement limités à l'étude d'une seule espèce d'arbre : Fraxinus excelsior L. , très commun dans notre zone d'étude et couvrant une vaste échelle d'altitude. Notre démarche analytique a consisté à combiner une analyse élémentaire très complète et sensible, l'ICP-MS avec une observation en microscopie à balayage couplée à la détermination de l'émission de rayons X spécifique des éléments présents. Cet ensemble de deux méthodes a permis de combiner identification - dosage précis - localisation - distinction entre états particulaire et dispersé. La déposition atmosphérique a été considérée sur une échelle de temps allant de 3 mois à 40 ans, en séparant les pousses successives des arbres. Nous avons séparé le dépôt superficiel sur les surfaces végétales d'une fraction solidement intégrée dans les tissus des tiges, spécialement le suber. Ces deux entités ne correspondent pas à la même chronologie. Nous avons montré que le dépôt de surface était, de fait, un écosystème construit sur un biotope alimenté conjointement par l'atmosphère et par l'arbre lui-même et qu'il comportait une phase vivante reviviscente et pour partie photosynthétique. Ce dépôt superficiel est déplacé en grande partie par la pluie. Le suber, couche apoplastique imperméable, a une bonne capacité de rétention des éléments à long terme et constitue, comparativement aux autres tissus des tiges, une matrice très intéressante pour percevoir l'apport atmosphérique sur plusieurs décennies. Pour déterminer valablement les apports atmosphériques d'origine anthropique qui s'accumulaient dans ces deux types de matrices, nous avons conçu un système de calcul (AAEF) permettant de les séparer des apports géogéniques et biologiques. Par ailleurs, constatant que l'apport atmosphérique comportait deux types de constituants, soit dispersés, soit particulaires, nous avons conçu et mis en œuvre un protocole de fractionnement basé 1) sur l'incinération, 2) sur les traitements successifs à l'eau et à l'acide nitrique concentré (2N) qui nous a permis d'étudier isolément une phase particulaire dans laquelle la masse des matériaux géogéniques se trouve rassemblée avec l'essentiel du plomb et du manganèse, la phase HNO3 concentrant les éléments comme le cuivre et le zinc et une phase H2O contenant l'essentiel du potassium. Les profils de distribution entre les différentes fractions semblent constituer une information intéressante sur la spéciation de plusieurs types d'éléments. L'ensemble du corpus méthodologique ainsi édifié permet d'accéder à des études assez réalistes d'historique et de distribution géographique des polluants élémentaires à des échelles de distances variées
Human activities are responsible for the atmospheric transfer of several types of compounds among which elements are present. One of the secondary effects of such transfer may be to affect human health and the functionality of ecosystems. After atmospheric transfer, a complex deposition of the elements occurs on the earth surface, with very unequal distribution, accumulation or dilution inducing quite different effects on water and soil composition and on the functionalities of living beings. The deposition process has been studied for approximately half a century on tree trunks. These organs constitute a very common vertical matrix on which quantitative or biomonitoring studies can be efficiently carried out, thus offering widely used routine tests. However, for a better exploitation of the information contained in such deposits, a much better understanding of this type of deposition was required. Such is the purpose of this report. A single tree species was chosen for this study: Fraxinus excelsior L. , a very common tree for our region, which was cultivated in the campus station and which could be found at several altitudes between 200 and 1700 m. Our methodological approach consisted in mixing two types of analytical techniques: ICP-MS and SEM-EDX which allowed to obtain an accurate concentration measurement of trace elements, a determination of their location or distribution at a microscopic scale and a chemical determination of the composition of crystallized or precipitated compounds. The time-scale of our studies on deposits ranged from 3 months to 40 years. Two types of fractions were analysed separately: a superficial one, on the stems, and another one, integrated inside the suber tissue and also inside other tissues. It was demonstrated that the superficial deposit was in fact a component of a specific small ecosystem characterized by a non-negligible photosynthetic rate and by a reviviscent ability. The superficial deposit is submitted to a partial lixiviation by rain. The suber tissue is a waterproof, apoplastic layer able to tightly retain most of the elements over long periods of time. It seems to be the best tissue for retaining atmospheric components over several decades. The deposit has several possible origins geogenic, biogenic or anthropogenic. In order to focus on this last fraction, a new system of calculation was conceived, which allows to determine the composition of an atmospheric anthropic elements fraction (AAEF). Moreover, this AAEF was fractionated into two parts, a dispersed one inside the deposit and a pattern of solid particles which were found either in the superficial deposit or inside the suber but not in the other tissues. A purification of the solid particles fraction was carried out, separating the water-soluble elements, the HNO3 2N-soluble ones and the solid residue. This last fraction contains most of the geogenic components, and of the Pb and Mn contents. The HNO3 fraction concentrates the elements such as Zn and Cu. The main purification steps are associated to the presence of the whole stock of dispersed K and Na inside the water phase and of Ca in the HNO3 fraction. This fractionation probably allows interesting speciation studies. With all these new experimental approaches, it seems possible to obtain realistic analyses of the historical and geographical distributions of elements deposits on different spatial scales

This thesis explores options for resolving the ongoing tenure and compensation conflicts in the off-reserve forests (non-plantation forests outside permanent forest reserves) in Ghana. The ongoing degradation of the forests has been attributed to the prevalent tenure and compensation conflicts among cocoa farmers, the government, and logging concessionaires. Cocoa farmers nurture and preserve naturally growing trees in the off-reserve forests. They even plant indigenous tree species on their farms for the purpose of providing additional shades for their cocoa crops. Yet since 1998, the government has denied farmers any legal rights to the shade trees they retain on their farms. In addition, crops are extensively damaged by logging and transporting activities occurring on cocoa farms. However, most concessionaires fail to adequately compensate affected farmers. Farmers tend to resort to unsustainable forest practices as a result of these tenure and compensation conflicts. They markedly reduce shade tree density when cocoa crops start bearing pods by cutting down or killing many young trees and engaging in illegal (chainsaw) logging. Thus, the key research question investigated by this thesis is: what is the most optimal policy option for minimising unsustainable forest practices among farmers? To respond to this question, this thesis developed game-theoretic models to predict the future behaviour of some key stakeholders under hypothetical policy scenarios. The predictions of the game-theoretic models were then tested with empirical data collected from farmers and concessionaires in Ghana in 2016. The current behaviours of the concessionaires and farmers in the off-reserve forests were found to be consistent with the rational-choice model. These stakeholders are behaving in ways that will maximise their expected values in the off-reserve forests. Both the theoretical and empirical results revealed that farmers are less likely to be fully compensated should they pursue compensation on their own. It was found that a credible threat of litigation by a third-party advocate is likely to be the most optimal option to ensure that concessionaires fully and promptly compensate farmers for crop damage. More importantly, the most optimal policy option to motivate farmers to increase tree density and diversity and minimise farmer-driven illegal logging is a policy mix that concurrently provides 40% of stumpage revenue to farmers; ensures full compensation for crop damage through third-party litigation; and strictly enforces the tree harvesting rule using FC-farmer partnerships.
Thesis (Ph.D.) -- University of Adelaide, School of Social Sciences, 2018

碩士
中國文化大學
資訊管理學系
99
This study investigated cross-domain applications used to bridge information technology and the Public Procurement Act. Through indirect reference to the literature and logical reasoning, it was found that the relationship between the two entities is complementary and requires further research. This study employed a decision tree model to parse the long, complicated provi-sions within the Public Procurement Act, focusing on cross-domain applications. We established a logical framework of classification and quantification that would enable government organizations to select the correct method when calling for bids in pro-curement cases. It was found that although this approach is applicable under normal work condi-tions, a number of special cases still require manual correction. We discovered that the selection of bids is determined by the individuals in charge as well as factors under con-sideration, such as time of delivery, price, the expectations of superiors, and the adapta-bility of suppliers. Each of these factors varies from case to case, resulting in differences in the derived frameworks. Disturbance variables such as the work attitudes of personnel, assigned tasks, and dedication of suppliers also have a strong influence on the selection of bids.