Dissertations / Theses: 'Tropical plantation'

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Tibok, Anthony. "Genetic improvement of the tropical forest plantation species Eucalyptus and Acacia." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260347.

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Villanueva, Teodoro R. "Integrated yield forecasting and harvest scheduling in a tropical pine plantation in Fiji." Thesis, University of Canterbury. Forestry, 1992. http://hdl.handle.net/10092/7588.

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This thesis reports on enhancements of two planning method components aimed at improving management and planning of forest plantations in the tropics. The two modular planning models subjected to detailed study are growth and yield modelling and harvest scheduling. A case study relating to Caribbean pine in Fiji is used to demonstrate the refined capability. Growth and yield modelling has been improved by applying modern statistical and computer techniques to solve non-linear equations that describe growth of stands appropriately. Further improvements have been achieved by developing diameter distribution growth and yield models solved by a combination of parameter recovery and prediction method thereby ensuring compatibility between average stand values and diameter distribution values. In conducting improvements in growth and yield models, data manipulation and data validation procedures are described and reviewed in detail to emphasize their importance, particularly for non-linear regression fitting of equations, growth, yield and diameter distribution projection modelling. Various growth projection equations were tested before final stand average functional forms for basal area per hectare, standard deviation of diameter at breast height outside bark, maximum diameter at breast height outside bark and survival per hectare were identified and then integrated into the growth and yield model. The precision of the equations was assessed through graphs and statistics relating to residuals. The stand simultaneous growth and yield equations solved and used in the model consist of modified forms of different growth projection functions, such as the Gompertz, exponential and Schumacher, which were then used to derive a diameter distribution based on the Reverse Weibull probability density function. The diameter distribution growth and yield model was prepared as a simulation model to predict stand average values then, in conjunction with existing stem volume and taper equations, to derive stand and stock tables that allow disaggregation of diameter classes into log types. Three simulation models were created, one in Vax Fortran, one in PC Fortran and the other in spreadsheet format to enhance the models's portability. The harvest scheduling model developed is a spreadsheet based LP model which is able to schedule harvests from a number of stands within a medium-term planning horizon using different logging methods with the log harvest to be delivered to different ports or utilization plants. A Fiji case study provided a demonstration of the modelling capability for fifteen stands, seven years, four logging methods and two ports. This new kind of LP harvest scheduling model was developed with a deliberate intention to facilitate the running of it with the input from the improved growth and yield model. In developing this harvest scheduling model, the nature of LP in general was first reviewed and compared to other tools of harvest scheduling like binary search and simulation. LP harvest scheduling was found in this review to be a widely used tool and solution algorithms for which abound. A major problem with most solutions was the need to cater for sophisticated report writing and matrix generation. These two concerns were specifically addressed in the model developed as part of this study. The use of a spreadsheet as input to the LP was seen to be an efficient way of overcoming some of the major criticisms levelled at LP by potential users. The methodology developed was also advantageous because of its capability to facilitate the integration of growth and yield outputs with harvest scheduling. It was concluded that forest planning models can be readily improved with software and hardware that developing countries can easily afford. The models reported here harness the capabilities of the now commonly employed spreadsheet as a powerful tool for easier routine input, output and sensitivity analysis, to assist decision making for harvest scheduling and to simplify managerial planning and control.

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Tchichellé, Sogni Viviane. "Production de biomasse et quantification des flux d’azote dans une plantation mixte d’Eucalyptus urophylla x grandis et d’Acacia mangium au Congo." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0115/document.

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Les plantations forestières représentent 5% de la surface forestière mondiale mais assurent plus du tiers de l’approvisionnement en bois de la planète. La durabilité de ces systèmes de production repose sur le maintien à long terme de leur fertilité, sans recourir à la fertilisation. L’introduction d’une espèce fixatrice d’azote (N) dans les plantations forestières est une des solutions envisagées pour relever ce défi. L’objectif de la thèse était d’évaluer l’effet de l’introduction de l’Acacia mangium dans une plantation pure d’eucalyptus sur la croissance des arbres, la production de biomasse et la dynamique de N dans le sol. Pour atteindre cet objectif, des inventaires destructifs combinés à une collecte des chutes de litière ainsi qu’un suivi annuel de la minéralisation de N dans le sol, ont été réalisés. Ils ont été associés à l’étude de la fixation symbiotique de N et de l’enrichissement en N de la matière organique particulaire. Cette étude a permis de mettre en évidence un effet positif de l’acacia sur la croissance des eucalyptus à travers une modification des relations interspécifiques. La relation de facilitation engendrée par la fixation symbiotique de N a été à l’origine d’une augmentation de la croissance des eucalyptus et de la production primaire nette aérienne. Cette augmentation de croissance était liée à l’amélioration du contenu azoté du sol, en particulier dans la fraction grossière de la matière organique particulaire. Une augmentation de la production de N par minéralisation a révélé un recyclage beaucoup plus rapide du N du sol. Ces travaux ouvrent des perspectives pour une intensification écologique de la sylviculture des plantations tropicales
Forest plantations represent 5% of the world forest area but provide more than one third of world wood supply. Sustainability of these systems is based on the long-term maintenance of their fertility without using fertilizers. The introduction of nitrogen (N) fixing species in forest plantations is one of the solutions to take-up this challenge. The aim of this work was to assess the effects of the introduction of Acacia mangium in pure stand of eucalypts on tree growth, biomass production and soil nitrogen dynamics. To achieve this goal, destructive inventories combined with quantification of N fluxes in litter fall and annual monitoring of N mineralization in soil, has been done. They were associated with study of the symbiotic fixation of N and N enrichment in particulate organic matter. The study highlighted a positive effect of acacia on the growth of eucalyptus through a modification of interspecific interactions. Facilitating relationship created by the symbiotic nitrogen fixation has been the source of an increase in the growth of eucalyptus and aboveground net primary production. This increased growth was related to improvement of the nitrogen content of the soil, especially in the coarse fraction of the particulate organic matter. An increase in nitrogen mineralization indicated a much faster soil nitrogen cycling. This work opens perspectives for an ecological intensification of tropical plantation forestry

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Ciglasch, Holger. "Insecticide dynamics in the soil environment of a tropical lychee plantation a case study from Northern Thailand /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980860342.

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Hamilton, Rachel Elizabeth. "The impact of forest conversion to oil palm plantation on the internal nitrogen cycle of tropical lowland soils." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5280/.

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This thesis seeks to quantify the effect of land use change from tropical forest to oil palm plantation on nitrogen biogeochemical cycling in Sabah, Malaysia (Borneo). Nitrogen cycling process rates and indices were examined across four forests and six oil palm plantations during the inter-monsoon and end of wet season in 2010 and 2012 respectively. Firstly, the study establishes a baseline to assess the impact of land use change along a chronosequence of forest succession. Results indicate that forests follow a trajectory of nitrogen recovery and increased “openness” to nitrogen cycling through secondary forest development. Secondly, the spatial and temporal variation of nitrogen cycling within oil palm plantations is assessed. Results show that plantation management practices result in spatial variability in soil nitrogen. Examining process rates revealed an increasing trend of N\(_2\)O emission and decreasing trends of soil organic matter content as plantations matured. However, season and soil type also affected denitrification and N\(_2\)O emission. Finally, a replicated comparison of process rates in forests and plantations on riparian and terra firme soils revealed that plantation establishment significantly altered rates of nitrogen cycling and resulted in greater emissions of N\(_2\)O from \(terra\) \(firme\) plantations.

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Setiari, Marwanto. "Study on decomposition characteristics of peat soils under oil palm plantation in Riau and West Kalimantan, Indonesia." Kyoto University, 2018. http://hdl.handle.net/2433/233851.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第21312号
農博第2297号
新制||農||1065(附属図書館)
学位論文||H30||N5146(農学部図書室)
京都大学大学院農学研究科地域環境科学専攻
(主査)教授舟川晋也, 教授縄田栄治, 教授北山兼弘
学位規則第4条第1項該当

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Amazonas, Nino Tavares. "High diversity mixed plantations in Brazil: Eucalyptus intercropped with native tree species." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-07052018-112057/.

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The high cost of restoring tropical forests is one of the greatest obstacle to achieving large-scale restoration. To overcome this barrier, we developed and implemented mixed plantations intercropping Eucalyptus with a high diversity of native tree species. The aim was to create favorable conditions for the regeneration of native species while simultaneously obtaining economic return from the exploitation of Eucalyptus as a commercial pioneer species. The use of Eucalyptus in this system is temporary and it shall be replaced by additional native species after it is harvested. In this research, we covered the main aspects and approaches of the effects of competition on tree growth using data from our restoration experiments. The objective of this research was to test the ecological viability of plantations that temporarily mix Eucalyptus spp. and a high diversity of native tree species during the initial phases of forest restoration as a strategy to offset implementation and maintenance costs. This alternative is investigated with a focus on the consequences of ecological interactions on tree survival and growth in three experiments implemented in the Atlantic Forest of Northeastern and Southeastern Brazil. We compared stands of native trees intercropped with Eucalyptus, traditional restoration plantations, and Eucalyptus monocultures. The thesis is structured in three main parts in which we focus in how the mixtures function compared to restoration plantations and Eucalyptus monocultures. We used forest inventories to understand the effects of competition and assessed ecophysiological parameters to provide insights about the mechanisms that affect tree growth when trees compete for water, light and nutrients. In the first part of the study, we showed that mixed plantations effectively combined high wood yield and tree diversity; that Eucalyptus grew larger in mixtures with native species than in monocultures; that native tree species grew less in mixtures with Eucalyptus; and that the mixing effect was stronger for fast- and intermediate-growing native species. In the second part, we found that mixtures consumed less water than monocultures; that Eucalyptus reduced the hydraulic performance of a fast-growing native species; and that tree growth was influenced by changes in the ecophysiology of water use. In the last part, we showed that a high diversity of nitrogen-fixing native trees facilitated Eucalyptus growth; that Eucalyptus had ~30% higher wood N concentration in mixtures; that native trees growth was not limited by nutrient competition with Eucalyptus; that Eucalyptus may benefit from increased light availability in mixed plantations; and that native species plots intercepted more sunlight than mixtures or Eucalyptus stands. This research has a strong interface between restoration science and practice, and contributed to the development of new ways to restore the tropical forests by allying restoration and production under the ecological and economic perspectives. Our findings indicate how to advance into the future, starting from the current state of art towards forest restoration systems that minimize competition and maximize growth, as an emergent promising alternative to finance tropical forest restoration and overcome the economic barrier that still holds large-scale restoration. This research may be used as a basis to continue adapting silviculture for different regions and forest ecosystems. Looking further into the future, these mixtures may also represent the starting point of a new silvicultural model that brings together production and conservation. The information available may be used by scientists, decision-makers, planners and restorationists to advance in the science and practice of restoration and silviculture in the tropics.
O alto custo de se restaurar as florestas tropicais são um dos maiores obstáculos para se atingir a restauração em larga escala. Para superar essa barreira, nós desenvolvemos e implantamos plantações mistas que intercalam Eucalyptus e uma alta diversidade de espécies arbóreas nativas. O objetivo é criar condições favoráveis para a regeneração das espécies nativas e, ao mesmo tempo, obter retorno econômico da exploração de eucalipto como uma espécie pioneira comercial. O uso do eucalipto nesse sistema é temporário e ele deve ser substituído por espécies nativa adicionais após ser colhido. Nessa pesquisa, nós cobrimos os principais aspectos e abordagens relacionados aos efeitos da competição sobre o crescimento arbóreo utilizando dados dos nossos experimentos. O objetivo dessa pesquisa foi testar a viabilidade ecológica de plantios que consorciam temporariamente eucalipto e uma alta diversidade de espécies arbóreas nativas durante as fases iniciais da restauração ecológica como uma estratégia para compensar parte dos custos de implantação e manutenção. Essa alternativa é investigada com foco nas consequências das interações ecológicas sobre a sobrevivência e o crescimento das árvores em três experimentos implantados na Mata Atlântica do nordeste e sudeste do Brasil. Nós implantamos e comparamos talhões de espécies nativas intercaladas com eucalipto, plantios de restauração tradicionais e monocultivos de eucalipto. A tese é estruturada em três partes principais com foco em como os plantios mistos funcionam em comparação a plantios de restauração e monocultivos de eucalipto. Nós utilizamos inventários florestais para entender os efeitos da competição e estimamos parâmetros ecofisiológicos para investigar os mecanismos que afetam o crescimento arbóreo quando as árvores competem por água, luz e nutrientes. Na primeira parte do estudo, nó mostramos que os plantios mistos combinaram efetivamente alta produção de madeira com diversidade arbórea; que eucalipto cresceu mais em plantios mistos do que em monocultivos; que espécies nativas cresceram menos em consórcio com eucalipto; e que o efeito do consórcio foi maior para espécies de crescimento rápido e intermediário. Na segunda parte, mostramos que plantios mistos consumiram menos água do que monocultivos; que Eucalyptus reduziu a performance hidráulica de uma espécie nativa de rápido crescimento; e que o crescimento das árvores foi influenciado por mudanças na ecofisiologia do uso da água. Na última parte, nós mostramos que uma alta diversidade de espécies arbóreas fixadoras de nitrogênio facilitaram o crescimento de Eucalyptus; que Eucalyptus teve concentração de N ~30% mais alta na madeira, em plantios mistos; que o crescimento de árvores nativas não foi limitado pela competição por nutrientes com eucalipto; que eucalipto pode se beneficiar de maior disponibilidade de luz em plantios mistos; e que parcelas de espécies nativas interceptaram mais luz do que plantios mistos ou monocultivos de eucalipto. Essa pesquisa tem uma forte interface entre a ciência e a prática da restauração, e contribuiu para o desenvolvimento de novas maneiras de se restaurar as florestas tropicais por meio da aliança entre restauração e produção sob as perspectivas ecológica e econômica. Nossas descobertas indicam como avançar no futuro, a partir do estado da arte atual, em direção a sistemas de restauração florestal que minimizem a competição e maximizem o crescimento, como uma alternativa emergente e promissora para compensar os custos da restauração e superar a barreira econômica que ainda impede a restauração em larga escala. Essa pesquisa pode ser utilizada como uma base para se continuar adaptando a silvicultura a diferentes regiões e ecossistemas florestais. Olhando para o futuro mais distante, esses plantios mistos podem também representar um ponto inicial de um novo modelo de silvicultura que alia produção e conservação. A informação disponibilidade deve ser utilizada por cientistas, tomadores de decisão, planejadores e restauradores para avançar com a ciência e a prática da restauração e da silvicultura nos trópicos.

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Yamamoto, Kodai. "ASSESSMENT OF CLIMATE AND LAND USE CHANGE IMPACTS ON FLOOD INUNDATION IN A HUMID TROPICAL RIVER BASIN：A CASE STUDY OF SUMATRA ISLAND IN INDONESIA." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263624.

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付記する学位プログラム名: グローバル生存学大学院連携プログラム
京都大学
新制・課程博士
博士(工学)
甲第23163号
工博第4807号
京都大学大学院工学研究科社会基盤工学専攻
(主査)教授立川康人, 教授田中茂信, 准教授佐山敬洋
学位規則第4条第1項該当
Doctor of Philosophy (Engineering)
Kyoto University
DFAM

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Healy, Chrystal. "The biodiversity-ecosystem functioning relationship : separating the effects of species richness, from those of species identity and environmental heterogeneity in a tropical tree plantation." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101136.

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This study attempts to expand existing knowledge on the relationship between biodiversity and ecosystem functioning, by studying a four year old tropical tree plantation. The growth of trees coming from monocultures, three species mixtures and six species mixtures was compared. Through multivariate statistical analysis, the variation in tree productivity was partitioned into different components: variation explained by (1) species richness, (2) species identity and (3) the environment. Results reveal that the environment explains the largest portion of variability in tree growth. Moreover, of the small amount of variation explained by diversity, species identity is found to be twice as important then species richness. Of notable significance was the amount of variation explained by the interaction of diversity with the environment.

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Sellami, Fatima. "Fonctionnement biologique du sol sableux sous plantations d’eucalyptus d’âges différents. Effets du reboisement sur les communautés de la macrofaune et des microorganismes du sol en milieu tropical (Congo) et méditerranéen (Maroc)." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST0066.

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Les plantations d'Eucalyptus, au Congo (région de Pointe-Noire) comme au Maroc (forêt de la Maâmora), soulèvent des controverses quant à leurs effets sur des sols sableux pauvres en matière organique. Dans un enjeu de développement durable de tels écosystèmes anthropiques, les recherches sur le sujet se sont multipliées. Toutefois, les connaissances relatives au fonctionnement biologique des sols sous ces plantations méritent encore d'être approfondies. Principaux acteurs de ce fonctionnement biologique, les organismes vivant dans ces sols et leurs activités ne sont que trop peu décrites, et nécessitent en ce sens de se trouver au cœur des études sur le sujet. Notre travail de thèse s'inscrit dans ces problématiques. Ainsi, nous évaluons les conséquences du reboisement sur les communautés de la macrofaune et des microorganismes de ces sols, et également l'activité des enzymes clés liées aux principaux cycles biogéochimiques (C, N et P).Cette recherche présente la particularité de la prise en compte simultanée de deux facteurs peu souvent évoqués, que sont, l'« âge des plantations » et la « profondeur du sol ». Nous avons abordé ces questions par une étude multi-échelle.Ainsi, nous avons étudié les macroinvertébrés quant à leur diversité taxonomique et à leur composition verticale, selon une approche combinée (TSPF + carré anglais). Par la suite, les premières caractérisations de structure et de diversité des communautés microbiennes ont été réalisées. Ceci, par mesure de densité et par déterminations morphotypiques (cultures in vitro) et génétiques (DGGE), au niveau des communautés totales. Par mesure du potentiel métabolique pour ce qui est des communautés fonctionnelles (plaques Biolog). Enfin, l'activité biologique des sols a été évaluée en mesurant l'activité de huit enzymes et l'activité microbienne globale (hydrolyse FDA).Ainsi, par comparaison à la forêt naturelle adjacente, cette étude nous a permis de mettre en évidence que l'introduction d'eucalyptus sur savane (Congo) ou sur chêne-liège dégradé (Maroc), modifie la structure et la diversité des communautés de la macrofaune et des microorganismes du sol ainsi que le profil des activités enzymatiques. Aussi bien en fonction de l'âge des plantations que de la profondeur du sol, ceci est valable. C'est le fonctionnement biologique qui se trouve donc impacté.Les proportions et les conséquences de cet impact restent toutefois particulières à chaque cas. Il faut cependant noter exception pour les activités enzymatiques liées au cycle de l'azote, qui apparaissent influencées de façon comparable dans les deux cas à l'étude. Ces activités diminuent significativement avec l'âge du peuplement, confirmant le statut déficitaire en azote de ce type de plantation
Eucalyptus plantations in Congo (Pointe-Noire region) and in Morocco (Mamora forest) raised certain controversies regarding their effects on the sandy poor soils. In such anthropogenic ecosystems, researches on the subject have multiplied in order to ensure their sustainable management. However, knowledge on the biological functioning of soils in these plantations still needs to be explored. Main actors of this biological functioning are soil organisms and their activities which have been described very little, and need to be more studied. Our thesis encompasses this problematic. Therefore, we evaluated the impact of reforestation on the communities of macrofauna and microorganisms of soil, and the activity of different key enzymes, as well, related to main biogeochemical cycles (C, N and P). This research presents, particularly, a simultaneous consideration of two factors rarely mentioned before: the "age of the plantations" and "soil depth". We addressed these issues by a multi-scale study. We studied macroinvertebrates by their taxonomic diversity and vertically composition by a combined approach (TSPF + English square). Subsequently, the characterization of structure and diversity of microbial communities was done by density measurements, morphotype-specific (in-vitro culture) and the genetic determinations (DGGE) and by measuring the metabolic potential in terms of functional communities (Biolog plates). Finally, soil biological activity was evaluated by determining the activity of eight different enzymes and the total microbial activity (FDA hydrolysis).Therefore, as compared to the adjacent natural forest soils, this study allowed us to demonstrate that the introduction of eucalyptus plantations, in savanna (Congo) or in degraded cork oak ecosystem (Morocco), alters the structure and diversity of macrofauna communities, soil microorganisms and the enzymatic activity profiles. Consequently, the biological functioning of the soils is impacted both in terms of the age of plantations and soil depth. However, the proportions and the consequences of this impact were very specific in each case, with the exception of enzymatic activities related to the nitrogen cycle, which influenced comparatively in both studies. These activities decreased significantly along with the stand age of eucalyptus plantations, confirming the deficient status of nitrogen in such plantations

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Schimann, Heidy Maria. "Impacts de perturbations liées à l'orpaillage sur l'évolution des communautés et fonctionnalités microbiennes d'un sol." Phd thesis, ENGREF (AgroParisTech), 2005. http://pastel.archives-ouvertes.fr/pastel-00001435.

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Ce travail s'intègre dans des problématiques actuelles cherchant à caractériser l'impact des activités humaines sur les écosystèmes. Le sol, et en particulier, les communautés microbiennes fonctionnelles, abordées simultanément en tant qu'actrices des bio-transformations et en tant que biodescriptrices de l'état fonctionnel du système, ont été l'objet d'étude de ce travail qui s'est articulé autour de deux questions majeures : - Il s'agissait de savoir si des communautés microbiennes du sol exerçant deux fonctions considérées comme représentatives du fonctionnement global (respiration et dénitrification) pouvaient, sur un sol minier revégétalisé, récupérer des performances similaires à celles d'un sol de forêt. Cette étude menée in situ en forêt guyanaise, sur une zone minière aurifère réhabilitée a montré une certaine réversibilité des activités microbiennes des sols observées lors d'une telle perturbation. En effet, malgré une texture extrêmement hétérogène, le sol, une fois replanté en légumineuses, retrouve un fonctionnement similaire à celui de la forêt. Les biodescripteurs utilisés (ratio respiration réelle/potentielle et dénitrification/ respiration) ont permis de caractérise les différences de fonctionnement le long de la séquence de reforestation. Ils se sont révélés pertinents pour décrire les sols en cours de reconstruction et de stabilisation. La valeur de ratio respiration réelle/potentielle dans un sol de forêt pourrait être considérée comme un indicateur de stabilité, spécifique du site et caractérisant l'état d'équilibre à atteindre. Enfin, en permettant de détecter des variations qualitatives de la matière organique des sols qui n'avaient pas été mises en évidence par le C/N, l'utilisation de l'analyse NIRS associée aux analyses d'activité enzymatiques microbiennes a permis de vérifier que la dynamique de reconstruction des sols avait été accélérée par la plantation. La seconde question majeure de ce travail était: quel est l'impact d'une première perturbation sur (i) la structure et le fonctionnement microbien du sol et sur (ii) la capacité du sol à résister à une seconde perturbation ? Pour y répondre, une expérience in vitro menée sur des microcosmes de sol subissant deux types de perturbations (mercure et chaleur) a été élaborée. Les résultats ont montré que la respiration et la dénitrification répondaient d'une manière différente avec, parallèlement, des modifications durables de la structure des communautés. La diversité génétique des communautés microbiennes du sol a été évaluée à l'aide d'une ARISA après une extraction directe de l'ADN du sol. Au préalable, une étude méthodologique avait permis d'évaluer les biais engendrés par différentes méthodes d'extraction de l'ADN et donc de choisir l'extraction directe de l'ADN. Le maintien, dans certains cas, des fonctions après perturbation (respiration inchangée après l'application du mercure; dénitrification importante malgré le choc de température) suggère une redondance fonctionnelle importante parmi les communautés microbiennes du sol. Pourtant l'application de mercure, semble induire une vulnérabilité plus importante des sols face à une autre perturbation (chaleur). Cette vulnérabilité se traduit par une modification du fonctionnement de la communauté hétérotrophe du sol (respiration potentielle) mais aussi par la quasi disparition de la dénitrification dans ces sols. Cela peut révéler une diminution de la stabilité des sols qui pourrait être due à la modification de diversité mise en évidence dès le début de l'expérience. L'ensemble des résultats posés au cours de ce travail doit être analysé au regard des concepts de maintien des cycles biogéochimiques et d'ingénierie écologique. Les expériences menées aussi bien sur la Mine Boulanger qu'en microcosmes ont permis de mettre en exergue la nécessité de définir des biodescripteurs pertinents, capables de décrire l'état du système mais aussi sa probable évolution. Les indicateurs microbiens fonctionnels utilisés semblent remplir cette fonction en étant capables de rendre compte de la "performance" du système, de sa possibilité à être réhabilité ou à résister aux perturbations

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Langi, Martina Agustina. "Nutrient cycling in tropical plantations and secondary rainforests /." St. Lucia, Qld, 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16357.pdf.

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Lacy, Philip Alan Physical Environmental &amp Mathematical Sciences Australian Defence Force Academy UNSW. "Burning Under Young Eucalypts." Awarded by:University of New South Wales - Australian Defence Force Academy. Physical, Environmental & Mathematical Sciences, 2009. http://handle.unsw.edu.au/1959.4/43663.

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Fuels management in eucalyptus plantations is essential to minimise the impact of wildfire. Prescribed burning has the potential to reduce the fuel hazard in plantations, but is not routinely conducted due to concerns relating to tree damage. Through a series of experimental burns, the issues of tree damage are addressed and minimum tree sizes are recommended that are capable of withstanding the effects of low to moderate intensity fires. Data was collected between 2005 and 2007 over six sites, two species, and three age classes. Tree response results came from multiple measurements of over 1700 individual trees. The fuel characteristics commonly found in sub-tropical eucalypt plantations from age four to eleven are described and quantified. These fuel characteristics are related to fire behaviour and new fire behaviour models, specific to young eucalypt plantations, are presented. The fuel characteristics that most influence fire behaviour in young eucalypt plantations are fuel load, fuel height, and fuel moisture content. These characteristics can be used to predict the rate of spread of a plantation fire under benign wind conditions. A novel technique for assessing the extent of stem damage in eucalypts is developed and described. This technique enables immediate assessment of stem damage following fire; previous assessment techniques recommend waiting a considerable period of time (up to 2 years) until dead bark dropped off and fire scars were evident. This new assessment technique is likely to be suitable for post-fire assessment of any eucalypt species and will provide forest managers with the capability of deciding whether to leave a stand to ???grow-on??? or commence recovery operations. Minimum stem sizes recommended to ensure no long-term damage are between 5 ??? 8 cm DBH (diameter at breast height, i.e. 1.3m above ground level) for Eucalyptus dunnii (Dunn???s white gum) and 5 ??? 13 cm DBH for Corymbia spp. (spotted gum) depending on the quantity of fuel around the stem. Stem sizes vary between species because of the variation in bark thickness between species. This thesis provides all the necessary information to conduct prescribed burning operations in young eucalypt plantations.

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Inman, Faith Marie. "USING ARTIFICIAL CANOPY GAPS TO RESTORE AVIAN HABITAT IN TROPICAL TIMBER PLANTATIONS." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-07142005-155017/.

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The potential for plantations to catalyze forest regeneration on highly degraded land and the need to research management methods to increase biodiversity within plantations have been widely recognized. Our study investigated the effects of creating artificial canopy gaps by girdling exotic timber trees in plantations on the germination, growth, and survival of native tree species that may be important food plants for the Puerto Rican parrot. We found that seedling growth increased significantly in gaps; there were no differences in survival or germination between gap and closed plots. Percentage cover of grasses, shrubs, and vines increased but did not prevent tree seedlings from growing significantly more in gaps. Leaf litter removal had no effect on germination, growth, or survival. Both local and landscape level diversity is predicted to increase in gaps if large saplings present in the understory replace the girdled timber trees, but plantations will still be dominated by exotics and timber species. Our results suggest that restoration of native forest diversity in plantations will require continued management to remove exotic species and promote growth of tree species with high wildlife habitat value.

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15

Laclau, Jean-Paul. "Dynamique du fonctionnement minéral d'une plantation d'eucalyptus. Effet du reboisement sur un sol de savane du littoral congolais ; conséquences pour la gestion des plantations industrielles." Phd thesis, INAPG (AgroParisTech), 2001. http://tel.archives-ouvertes.fr/tel-00005778.

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Cette étude avait pour objectifs principaux d'étudier le fonctionnement minéral d'une plantation d'eucalyptus et d'évaluer les effets du reboisement sur un sol de savane du littoral congolais. Une amélioration des systèmes de culture était également recherchée, afin d'assurer une production soutenue et durable de bois d'eucalyptus dans ces sols.
Les cycles biogéochimiques ont été étudiés dans une plantation clonale d'eucalyptus âgée de 6 à 9 ans (fin de la rotation) et dans une savane représentative de l'écosystème originel. Les stocks d'éléments biodisponibles dans les sols des 2 écosystèmes ont été quantifiés et les principaux flux d'éléments minéraux sous forme dissoute ont été mesurés pendant 3 années : apports atmosphériques, pluviolessivats, écoulements de troncs, ruissellements superficiels, transferts sous la litière et à la base des différents horizons pédologiques (jusqu'à 6 m de profondeur). Lors du brûlis de la savane, les restitutions au sol sous forme de cendres ainsi que les transferts dans l'atmosphère ont été quantifiés. La localisation spatiale des racines a également été étudiée dans la plantation ainsi que la dynamique d'incorporation des éléments dans la savane entre 2 brûlis annuels. L'étude de chronoséquences de peuplements couvrant l'ensemble de la rotation de futaie a permis d'aborder les dynamiques (i) d'incorporation d'éléments minéraux dans la biomasse, (ii) de retours au sol avec les litières, ainsi que (iii) de transferts internes dans les arbres.
Les résultats montrent que les cycles biogéochimiques dans l'écosystème de savane ont été profondément modifiés par la plantation d'eucalyptus. Le cycle de l'azote a été le plus affecté en raison de l'arrêt des brûlis et de la fixation symbiotique, qui représentent des flux importants en savane. Ce clone d'eucalyptus s'est révélé très bien adapté malgré la pauvreté des sols, en raison en particulier d'un recyclage intense d'éléments nutritifs. Les transferts internes de N, P, K dans la biomasse et les restitutions importantes de N, Ca et Mg avec les litières permettent de limiter la dépendance des arbres vis à vis des réserves du sol en fin de rotation. Les bilans entrées-sorties indiquent néanmoins que les fortes productions de biomasse des eucalyptus ont lieu aux dépens du capital d'azote hérité de la savane et qu'une augmentation importante des apports par fertilisation sera indispensable pour maintenir la production. Des recommandations sylvicoles ont été proposées afin de limiter au maximum les exportations minérales et orienter les futures expérimentations.

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16

Cook, Sarah. "Fluvial organic carbon losses from tropical peatland oil palm plantations in Sarawak, Malaysia." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42510.

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Currently, there are only very limited estimates of carbon loss from oil palm plantations (OPPs) on tropical peat, with the aquatic fluxes largely unquantified. This thesis presents an annual estimate of exported dissolved (DOC) and particulate (POC) organic carbon from the drainage waters of four OPPs and nearby stands of tropical peat swamp forest (PSF) in Sarawak, Malaysia, subjected to varying degrees of anthropogenic disturbance. Annual total organic carbon (TOC) fluxes (104 ± 19.3 g C m-2 yr-1) from the OPPs explored here are one third larger than those from intact PSFs (63 g C m-2 yr-1) and comparable to fluxes from degraded PSFs (97 g C m-2 yr-1) as reported in the literature. Forest fluxes measured in this project were of a similar magnitude (71.2 ± 11.0 to 84.5 ± 13.1 g C m-2 yr-1), likely as a result of hydrological disturbance from the adjacent plantation drainage system. Qualitative analysis (14C and spectrophotometric analysis) of DOC derived from the OPP land cover revealed that the majority (> 50 %) originates from aged carbon sources (100 – 499 years, BP) and is both labile and highly oxidised, suggesting loss of carbon from long-term stable storage. Extrapolation of the plantation sub-catchment fluxes indicates that industrial peatland OPPs across Peninsular Malaysia, Borneo and Sumatra contribute a combined TOC flux of 3.2 Tg C yr-1. This represents one third of the regional TOC flux (10.4 Tg C yr-1; PSF intact + degraded + industrial OPPs) and suggests a more than two-fold increase in TOC losses since 1990. Overall, this investigation reinforces the importance of considering alternative fluvial carbon loss pathways when assessing the on-going collapse of tropical peatland carbon stores in response to their continued anthropogenic exploitation.

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Murphy, Meaghan Thibault. "Biotic and abiotic controls on soil respiration in a biodiversity plantation in the tropics." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97978.

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The Sardinilla plantation is a long-term facility for studying the links between tree species diversity and ecosystem function. Six native tree species were planted in 2001 in plots containing 1, 3 or 6 species. Soil respiration (SR) measurements were conducted from March to December 2004 on tree pairs. ANOVAs with repeated measure on days were used to test the main effects of species (monocultures), pair (single and two-species pairs), plot (pairs in monoculture, three-, and six-species plots), and season (dry vs. early wet season). ANCOVAs were run for each effect to determine possible biotic and abiotic covariates, including root, tree, and microbial biomass, soil moisture, surface temperature, and bulk density. Significant season and pair effects accounted for 89% and 2% of the variability in SR. Driven by soil moisture, SR increased seven fold during the seasonal transition. In the dry and wet season monocultures had significantly higher SR than two-species pairs.

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18

Thongo, M'Bou Armel. "Etude du système racinaire de l’Eucalyptus en plantation tropicale : analyse architecturale, croissance et respiration." Thesis, Nancy 1, 2008. http://www.theses.fr/2008NAN10039/document.

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L’objectif de cette étude a été d’étudier le développement du système racinaire du clone d’Eucalyptus 1-41 au Congo. L’architecture du système racinaire a été abordée dans une chronoséquence. Elle a permis de définir une typologie composée de cinq catégories de racines assurant trois fonctions essentielles : l’exploration grâce aux racines latérales et pivotantes, l’exploitation du milieu assurée par un réseau de racines fines et la réexploitation du milieu, qui se fait par la mise en place tardive d’un système racinaire traçant. Tous ces types racinaires se mettent en place au cours du temps, grâce à une stratégie réitérative, qui permet au système racinaire de se déployer dans un volume important de sol. L’étude de la respiration racinaire a permis de paramétrer un modèle décomposant la respiration totale en des termes dépendants de la croissance, de l’entretien et de l’absorption minérale. Les paramètres de ce modèle ont ensuite été appliqués sur des données de biomasse et minéralomasse au champ afin d’estimer la respiration des racines fines à l’échelle du peuplement. Les résultats obtenus se rangent bien dans la gamme des mesures in situ au champ. L’étude de la production des racines fines a permis de mettre en évidence une forte variation des estimations en fonction des méthodes de prélèvement utilisées. Cependant l’estimation la plus réaliste donne un turnover racinaire de l’ordre de 4 an-1, impliquant un important retour d’éléments minéraux et de carbone dans le sol. Les résultats de cette étude offrent de bonne perspective pour développer un modèle architectural utile pour l’établissement des bilans de carbone, d’eau et de nutriments des plantations d’Eucalyptus au Congo
The aim of this study was to study the development of the root system of the 1-41 clone of Eucalyptus in Congo. Root architecture was studied in an age serie stands. A root typology was proposed with five classes of roots and three main functions: soil exploration with both lateral and vertical roots, soil exploitation with a network of fine roots and re exploitation of the soil zone by late emitted roots. All of these root types appeared at all the studied stages because of reiterations that allow the root system to explore a large soil volume. The results of root respiration study were used to parameterize a root respiration model with root respiration partitioned between a growth component, a maintenance component and a nutrient absorption component. The model was then applied using field data of fine root biomass and nitrogen content of whole tree biomass to estimate fine root respiration of a Eucalyptus stand. The simulated value fits reasonably well with independent estimates of root respiration in this site. Estimations of fine root production and turnover were highly variable depending of the methods used. The more realistic one predicts a turnover of 4 year-1, i.e. a high recycling of carbon and nutrient by belowground litter. Results of this study offer promising perspective for developing an architectural model of root development and its use to establish carbon, water and nutrient budget in Congolese Eucalypt plantation

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Thongo, M'Bou Armel Epron Daniel Mialoundama Fidèle. "Etude du système racinaire de l'Eucalyptus en plantation tropicale analyse architecturale, croissance et respiration /." S. l. : S. l. : Nancy 1 ; Université Marien Ngouabi, Brazzaville, 2008. http://www.scd.uhp-nancy.fr/docnum/SCD_T_2008_0039_THONGO-MBOU.pdf.

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Thèse de doctorat : Biologie végétale et forestière : Nancy 1 : 2008. Thèse de doctorat : Biologie végétale et forestière : Université Marien Ngouabi, Brazzaville : 2008.
Thèse soutenue en co-tutelle. Titre provenant de l'écran-titre.

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20

Hartemink, Alfred E. "Soil fertility decline in the tropics with case studies on plantation crops." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394197.

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Loumeto, Jean Joël. "Le système litière des forêts à peuplements d'Okoumé (Aucoumea klaineana) : exemples de deux sites congolais, la forêt du Chaillu et la forêt du littoral." Paris 6, 2002. http://www.theses.fr/2002PA066536.

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22

Pardon, Lénaïc. "Modelling of the nitrogen budget of oil palm plantations to help reduce losses to the environment. Case study in Sumatra, Indonesia." Thesis, Paris, Institut agronomique, vétérinaire et forestier de France, 2017. http://www.theses.fr/2017IAVF0018/document.

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L’humanité fait face aux défis urgents de réduire l’impact environnemental de l’agriculture, de changer les régimes alimentaires et d’accroître la production alimentaire. Le palmier à huile est une plante pérenne tropicale emblématique de ces défis. Alors que sa culture peut être à l’origine d’impacts environnementaux, le palmier à huile peut produire, en conditions optimales, 7 à 10 fois plus d’huile alimentaire que les cultures oléagineuses annuelles. Dans ce contexte, améliorer la durabilité de la production d’huile de palme est crucial, tant pour réduire les impacts environnementaux négatifs que pour garantir la sécurité alimentaire. L’application de fertilisants azotés (N) a été identifiée comme une source majeure d’impacts environnementaux dus à la culture du palmier. Des analyses de cycle de vie de l’huile de palme ont été réalisées pour quantifier les impacts et identifier des améliorations de pratiques agricoles. Cependant, les seuls modèles d’émissions disponibles pour estimer les pertes de N dans l’environnement sont généralement valides pour les cultures annuelles et en climat tempéré. L’utilisation de tels modèles dans l’analyse de cycle de vie peut mener à des résultats très incertains ou à une faible sensibilité aux pratiques. L’objectif global de ce travail de recherche était d’aider à l’identification de pratiques pour réduire les pertes de N dans l’environnement. Le cœur du travail était le développement d’un modèle estimant toutes les pertes de N dans les plantations, tout en étant sensible aux pratiques. L’étude s’est concentrée sur les flux de N dans les plantations de palmiers sur sols minéraux. Nous avons réalisé quatre étapes pour mener à bien cette recherche. Premièrement, nous avons mené une revue de littérature de tout le savoir existant concernant les flux et pertes de N dans les plantations. Deuxièmement, nous avons comparé 11 modèles existants, pouvant être utilisés pour prédire les pertes de N dans les plantations. Troisièmement, nous avons réalisé une analyse de sensibilité de Morris approfondie du modèle mécaniste APSIM-Oil palm. Quatrièmement, nous avons construit IN-Palm, un indicateur agri-environnemental pour les pertes de N dans les plantations. Nous avons utilisé la méthode INDIGO® et l’approche de modélisation par arbres de décisions flous pour développer IN-Palm, et nous avons validé cet indicateur en utilisant des mesures de lixiviation de N d’une plantation à Sumatra, Indonésie. Notre revue de littérature et notre comparaison de modèles ont montré que les particularités du palmier à huile peuvent affecter significativement les dynamiques et pertes de N. Nous avons identifié des manques de recherche et des incertitudes sur les pertes de N, leurs déterminants et la modélisation des particularités du palmier. Nous avons identifié les déterminants des pertes de N et du rendement dans le modèle mécaniste APSIM-Oil palm. Nous avons développé IN-Palm, qui utilise 21 variables d’entré facilement accessibles pour estimer chaque voie de perte de N. Les prédictions de lixiviation de N par IN-Palm étaient acceptables, et IN-Palm s’est montré efficace pour tester des changements de pratiques agricoles. Cette recherche constitue une synthèse exhaustive des connaissances et modèles disponibles pour les flux et pertes de N dans les plantations. L’un des principaux résultats est un nouvel indicateur agri-environnemental, IN-Palm, sensible aux pratiques et conditions locales, de même qu’utilisable en tant que modèle d’émission dans des approches holistiques. Cet indicateur peut être une base utile pour de futures recherches sur l’utilisation d’indicateurs agri-environnementaux pour réduire l’incertitude des analyses cycle de vie, et pour de futures adaptations à d’autres plantes pérennes tropicales
Humanity faces the challenges of urgently decreasing the environmental impact of agriculture, shifting diets and increasing food production. Oil palm is a tropical perennial crop emblematic of these challenges. While its cultivation can be associated with environmental impacts, oil palm can produce 3 to 7 t of edible oil ha-1 in optimal conditions, which is 7 to 10 fold higher than in annual oil crops. In this context, improving palm oil production sustainability is crucial for both reducing negative environmental impacts and ensuring food security. Application of synthetic nitrogen (N) fertilisers was identified as a major source of environmental impacts associated with the cultivation of oil palm. Life cycle assessments of palm oil have already been performed to help quantify impacts and identify potential improvements of management practices. However, the only available emission models to estimate N losses to environment are generally valid for annual crops and temperate climate conditions. The use of such general models in life cycle assessment may lead to very uncertain results or to low sensitivity of assessments to management practices. The overall objective of this research work was to help identify management practices to reduce N losses in the environment. The core of the work was hence to develop a model that estimates all N losses in oil palm plantations, while being sensitive to management practices. The study focused on N fluxes in industrial oil palm plantations on mineral soils. We performed four steps in order to complete the objectives of this research work. First, we conducted a literature review of all the existing knowledge about N fluxes and losses in plantations. Second, we compared 11 existing models that may be used to predict N losses in plantations. Third, we performed an in-depth Morris’s sensitivity analysis of one of the models, the APSIM-Oil palm process-based model. Fourth, we used all the information identified in the previous chapters, together with expert knowledge, to build IN-Palm, an agri-environmental indicator for N losses in oil palm plantations. We used the INDIGO® method and the fuzzy decision tree modelling approach to develop IN-Palm, and we validated this indicator using a field dataset of N leaching from a plantation in Sumatra, Indonesia. Our literature review and model comparison showed that oil palm peculiarities may impact significantly N dynamics and losses. We identified research gaps and uncertainties about N losses, their drivers and the modelling of oil palm peculiarities. We identified the main drivers of N losses and yield in the APSIM-Oil palm processbased model. We built IN-Palm, which uses 21 readily available input variables to estimate each N loss pathway. IN-Palm predictions of N leaching were acceptable, and IN-Palm has shown efficient to help testing management changes. This research constitutes a comprehensive synthesis of the available knowledge and models for N fluxes and losses in oil palm plantations. One of the main results is a novel agri-environmental indicator, IN-Palm, operationally-oriented, sensitive to local practices and environmental conditions, as well as potentially useable as an emission model for holistic approaches such as life cycle assessment. The INDIGO® method and fuzzy decision tree modelling approach were shown to be very well adapted for building agri-environmental indicators in contexts of knowledge scarcity. This indicator can be a useful base for further research about using agrienvironmental indicators to reduce uncertainty in life cycle assessment, and for future adaptations for other tropical perennial crops

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23

Pardon, Lénaïc. "Modelling of the nitrogen budget of oil palm plantations to help reduce losses to the environment. Case study in Sumatra, Indonesia." Thesis, Paris, Institut agronomique, vétérinaire et forestier de France, 2017. https://researchonline.jcu.edu.au/52952/1/52952-pardon-2017-thesis.pdf.

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Humanity faces the challenges of urgently decreasing the environmental impact of agriculture, shifting diets and increasing food production. Oil palm is a tropical perennial crop emblematic of these challenges. While its cultivation can be associated with environmental impacts, oil palm can produce 3 to 7 t of edible oil ha⁻¹ in optimal conditions, which is 7 to 10 fold higher than in annual oil crops. In this context, improving palm oil production sustainability is crucial for both reducing negative environmental impacts and ensuring food security. Application of synthetic nitrogen (N) fertilisers was identified as a major source of environmental impacts associated with the cultivation of oil palm. Life cycle assessments of palm oil have already been performed to help quantify impacts and identify potential improvements of management practices. However, the only available emission models to estimate N losses to environment are generally valid for annual crops and temperate climate conditions. The use of such general models in life cycle assessment may lead to very uncertain results or to low sensitivity of assessments to management practices. The overall objective of this research work was to help identify management practices to reduce N losses in the environment. The core of the work was hence to develop a model that estimates all N losses in oil palm plantations, while being sensitive to management practices. The study focused on N fluxes in industrial oil palm plantations on mineral soils. We performed four steps in order to complete the objectives of this research work. First, we conducted a literature review of all the existing knowledge about N fluxes and losses in plantations. Second, we compared 11 existing models that may be used to predict N losses in plantations. Third, we performed an in-depth Morris's sensitivity analysis of one of the models, the APSIM-Oil palm process-based model. Fourth, we used all the information identified in the previous chapters, together with expert knowledge, to build IN-Palm, an agri-environmental indicator for N losses in oil palm plantations. We used the INDIGO® method and the fuzzy decision tree modelling approach to develop IN-Palm, and we validated this indicator using a field dataset of N leaching from a plantation in Sumatra, Indonesia. Our literature review and model comparison showed that oil palm peculiarities may impact significantly N dynamics and losses. We identified research gaps and uncertainties about N losses, their drivers and the modelling of oil palm peculiarities. We identified the main drivers of N losses and yield in the APSIM-Oil palm process-based model. We built IN-Palm, which uses 21 readily available input variables to estimate each N loss pathway. IN-Palm predictions of N leaching were acceptable, and IN-Palm has shown efficient to help testing management changes. This research constitutes a comprehensive synthesis of the available knowledge and models for N fluxes and losses in oil palm plantations. One of the main results is a novel agri-environmental indicator, IN-Palm, operationally-oriented, sensitive to local practices and environmental conditions, as well as potentially useable as an emission model for holistic approaches such as life cycle assessment. The INDIGO® method and fuzzy decision tree modelling approach were shown to be very well adapted for building agri-environmental indicators in contexts of knowledge scarcity. This indicator can be a useful base for further research about using agri-environmental indicators to reduce uncertainty in life cycle assessment, and for future adaptations for other tropical perennial crops.

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Martineaud, Franck-Louis-Léon. "La pratique médicale dans une exploitation agro-industrielle dans le nord-Gabon." Bordeaux 2, 1989. http://www.theses.fr/1989BOR25064.

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Reis, Mariana Gonçalves dos. "Carbon, water and energy fluxes in Eucalyptus plantations and Savanna in Brazilian tropics." Universidade Federal de Viçosa, 2018. http://www.locus.ufv.br/handle/123456789/20478.

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No Brasil, a área com plantações de eucalipto é superior a 5,7 milhões de ha, destacando-se o estado do Mato Grosso do Sul (MS), que liderou a expansão em áreas plantadas nos últimos cinco anos (2011-2016). A maior parte dessas áreas plantadas no estado do MS está em áreas de floresta nativa do Cerrado, que foram substituídas principalmente por pastagens degradadas e culturas anuais no passado. Portanto, os efeitos desta alteração na cobertura do solo, no ciclo regional de carbono e da água ainda não estão compreendidos. Neste contexto, foi usada a técnica de covariância dos vórtices turbulentos, medidas meteorológicas, do solo e da vegetação para explorar as eficiências intrínsecas do uso da água e da radiação em dois diferentes estudos nos trópicos brasileiros: Primeiro estudo (1) teve como objetivo avaliar um ciclo completo de rotação (9 anos) de fluxos de carbono e água de uma plantação clonal de Eucalyptus grandis. No geral, as variáveis ambientais, radiação fotossinteticamente ativa (PAR), temperatura do ar (Tair), déficit de pressão de vapor de água (VPD), precipitação e o conteúdo de água no solo (SWC) seguiram as condições sazonais de época seca e chuvosa. Durante os 9 anos de estudo, a precipitação total anual variou entre 986 e 1496 mm ano -1 , com uma média de 1238 mm ano -1 . Antes do corte das árvores, a floresta de eucalipto mostrou-se ser um forte sumidouro de carbono durante todos os anos (1-8 anos), a soma anual da produtividade líquida do ecossistema (NEE) aumentou de -256 para -1515 g C m -2 ano -1 , a soma anual da produção primária bruta (GPP) aumentou de 2312 para 4059 g C m -2 ano -1 , e a soma anual da respiração do ecossistema (Reco) aumentaram de 1195 para 2751 g C m -2 ano -1 . O primeiro ano após o corte das árvores (incluindo a preparação do local e o anovo plantio), a soma anual foi NEE = 883, GPP = 1248 e Reco = 2132 g C m -2 ano -1 , indicando ser fonte de carbono neste período. Assim, o total de carbono sequestrado durante um ciclo completo de rotação foi de 78 t C ha -1 . O balanço de energia (Rn = LE + H + G) descreveu padrões diários típicos de transferência de calor sensível, calor latente e fluxo de calor no solo com fluxos máximos ao meio-dia solar. A evapotranspiração (ET) total anual variou entre 837 e 1432 mm ano -1 , com uma média de 1154 mm ano -1 . A eficiência intrínseca de uso da água (WUE i ) e a condutância do dossel (g c ) corresponderam as variações do índice de área foliar (IAF), GPP e ET durante o período de estudo. Em conclusão, os nossos resultados forneceram uma importante contribuição dos balanços de carbono, água e energia em um ciclo completo de rotação em plantações de eucalipto que podem ser úteis para avaliar mudanças de cobertura do solo nesta região e até mesmo em outras regiões do Brasil. Segundo estudo (2) o objetivo foi comparar as diferenças nos fluxos de carbono, água e energia entre uma floresta nativa de Cerrado (SAV) e em plantações de eucalipto (EUC) durante o período de dezembro de 2012 a agosto de 2013. Os valores diários da Tair (média de 23 °C), PAR (média de 34 mol m -2 dia -1 ) e da precipitação acumulada (soma 1013,5 mm) foram semelhantes entre os dois ecossistemas. Ao contrário, os valores diários de VPD e SWC foram menores no ecossistema da SAV do que no ecossistema EUC ao longo do período estudado. A soma da NEE (-1136 g C m -2 ) para este período indica que o ecossistema com EUC é sumidouro de carbono, ao contrário, para o ecossistema com SAV a soma da NEE (256 g C m -2 ) indicou ser um ecossistema fonte de carbono. No geral, o fluxo de calor latente (LE) dominou o balanço de energia em ambos os ecossistemas, seguido pelo fluxo de calor sensível (H) e pelo fluxo de calor do solo (G). A evapotranspiração total na SAV e no EUC foi estimada em 948 e 1050 mm, respectivamente. O índice de área foliar (LAI) no ecossistema SAV variou de 3,8 a 1,9 m -2 m -2 e no ecossistema EUC variou de 4,7 a 3,2 m -2 m -2 , no período úmido e seco, respectivamente. Considerando o período estudado, o cerrado foi fonte de carbono do ecossistema para a atmosfera (2,5 t C ha -1 ), já o plantio de eucalipto foi um forte consumidor de carbono da atmosfera para o ecossistema (11 t C ha -1 ) ao longo do estudo período (9 meses). Os resultados indicam que as plantações de eucalipto no bioma de savana estão bem adaptadas às condições ambientais e têm uma boa resposta à variabilidade das condições climáticas. Além disso, a mudança da cobertura do solo e as práticas de uso do solo do cultivo com pastagens para plantações de eucalipto podem ajudar ou mesmo restaurar a biodiversidade do bioma de savana
In Brazil the eucalyptus’s plantations area is higher than 5.7 million ha, stand out for Mato Grosso do Sul State (MS) which had led the expansion over the last five years (2011-2016). Most of these areas in MS are into a native savanna forest replaced by degraded pasture and annual crops in the past. Therefore, the effect of this land-cover change on regional carbon and water cycle remains unclear. Here, it was used the eddy covariance technique, meteorological, soil and plant measurements to explore the environmental dependence of intrinsic water- and radiation efficiencies in two different studies in Brazilian tropics: First study (1) reported a full rotation cycle (9 years) of carbon, water and energy fluxes from a clonal Eucalyptus grandis plantation. Overall the environmental variables, photosynthetically active radiation (PAR), air temperature (Tair), water vapor saturation pressure deficit (VPD), rainfall, and soil water content (SWC) followed seasonal drought and wet conditions. During the 9-years of study, the annual total rainfall ranged between 986 to 1496 mm yr -1 , with an average of 1238 mm yr -1 . Before the harvest of trees, the eucalyptus forest was a strong carbon sequestration during all years (1-8 years), the annual net ecosystem exchange (NEE) sum increased from -256 to - 1515 g C m -2 yr -1 , the annual gross primary production (GPP) sum increased from 2312 to 4059 g C m -2 yr -1 , and the annual ecosystem respiration (Reco) sum increased from 1195 to 2751 g C m -2 yr -1 . The first year after harvest of trees (including site preparation and planting of new trees), the annual sum was NEE = 883, GPP = 1248 and Reco = 2132 g C m -2 yr -1 , indicating a small carbon source for this period. Thus, the total carbon sequestration during a full rotation cycle was 78 t C ha -1 . Energy balance (Rn = LE + H +G) described typical daily patterns of sensible, latent and soil heat transfer, with maximal fluxes at solar noon. The annual total evapotranspiration (ET) ranged between 837 to 1432 mm yr -1 , with an average of 1154 mm yr -1 . Patterns in intrinsic water-use efficiency (WUE i ) and canopy conductance (g s ) during the study matched those variations in leaf area index (LAI), GPP and ET. In conclusion, our results provide an important contribution of carbon, water and energy balance in a full rotation cycle of eucalyptus plantations that can be useful to evaluate land-cover changes for this region and even in other regions of Brazil. Second study (2) the goal was to compare the differences in carbon, water and energy fluxes between a native Savanna forest (SAV) and eucalyptus plantation (EUC) during December 2012 to August 2013. The daily Tair (mean 23 °C), PAR (mean 34 mol m -2 day -1 ), and rainfall cumulative (sum 1013.5 mm) were similar among the two ecosystems. In contrast, the daily values of VPD and SWC were lower in SAV than EUC throughout the study period. The sum of NEE (-1136 g C m -2 ) for this period indicates that the ecosystem with EUC is a carbon sink, in contrast, for the SAV ecosystem the sum of NEE (256 g C m -2 ) indicated to be a carbon source ecosystem. Overall, the latent heat flux (LE) dominated the energy balances at both ecosystems, followed by sensible heat flux (H) and soil heat flux (G). The total ET at the SAV ecosystem and EUC ecosystem was estimating as 948 and 1050 mm, respectively. Leaf area index (LAI) in SAV ecosystem varied 3.8 to 1.9 m -2 m -2 , and in EUC ecosystem varied 4.7 to 3.2 m -2 m -2 , wet and dry period respectively. In summary, the savanna ecosystem was a weak carbon source from the ecosystem to atmospheric (2.5 t C ha -1 ), and the eucalyptus ecosystem was a strong carbon sink from the atmosphere to ecosystem (11 t C ha -1 ) over the study period (9 months). The results indicate that the eucalyptus plantations in savanna biome are well adapted to the environmental conditions and have a good response to variability of climate conditions. In addition, the land-cover change and land use practices from pasture to eucalyptus plantations can help or even restore the biodiversity of savanna biome

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Abe, Hitofumi. "Forest management impacts on growth, diversity and nutrient cycling of lowland tropical rainforest and plantations, Papua New Guinea." University of Western Australia. School of Plant Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0098.

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[Truncated abstract] Globally, tropical rainforests are noted for their high biodiversity and key roles in carbon storage and influence on climate. Nevertheless, tropical deforestation in many parts of the world continues at an alarming rate. In Papua New Guinea (PNG), tropical rainforest is relatively well maintained, with about 70 % of the land area still covered by primary forest. However, PNG's native forests are coming under increasing pressure, particularly from selective logging for high quality timber. While the forests of PNG, and more broadly the entire New Guinea Island, are recognised as of high conservation and ecological significance, they remain grossly understudied with little knowledge of key ecosystem processes within lowland forests in particular. Such knowledge is urgently required if the impacts of logging and other land-use change are to be assessed and in order to develop sustainable management systems. This thesis investigated the impacts of logging on diversity and nutrient cycling in a lowland tropical rainforest growing on limestone soils in the area of the Mongi-Busiga Forest Management Agreement (FMA, which is a logging concession area), in northeastern PNG. These forests are on relatively young soils and provide a useful contrast to the majority of tropical forests. The research includes a four-year study of the recovery of diversity and structure after logging, and quantified forest structure, tree species diversity, forest biomass and productivity, and nutrient distribution and cycling. This thesis also examines the ecological sustainability of Eucalyptus deglupta plantations in Wasab, PNG as an alternative resource for timber and biomass energy. The thesis concludes with a discussion of long-term forest recovery and sustainable forest management in north-eastern PNG. Two adjacent one-hectare plots were established in lowland tropical rainforest at Mongi-Busiga FMA. One of these plots was subsequently selectively logged, one year after establishment. Before logging, the two one-hectare plots contained a total of 37 families, 70 genera and 110 tree species that were >5 cm in diameter at breast height. Mean basal area was 42.4 m2 ha-1. Two tree species, Madhuca leucodermis (Sapotaceae) and Pometia pinnata (Sapindaceae) accounted for ~60% of the total basal area. Gymnacranthera paniculata (Myristicaceae) was the most common species and accounted for 13% of individuals. ... This study concludes that the Mongi-Busiga forest has many unusual characteristics for a tropical forest, including relatively low diversity of tree species, high accumulation of P in the biomass, and N limitations, compared to other tropical rainforests. However, those extraordinary characteristics may be explained well by the underlying geology of young, marine-derived limestone. Sustainable management of the lowland tropical forests of PNG should consider the consequences of logging on nutrient cycling processes, with the possible significant removal of P from site with repeated logging, as well as the interactions between N and P in these systems. Establishment of Eucalyptus plantations on previously cleared land also has the potential to meet some of the timber and biomass energy requirements of northern PNG in ecologically sustainable manner.

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George, Laurel. "Applications of solid-state 15N NMR spectroscopy to the study of nitrogen cycling in sub-tropical forest plantations." Thesis, View thesis, 2008. http://handle.uws.edu.au:8081/1959.7/39262.

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The aim of this research project was to use 15N nuclear magnetic resonance (NMR) spectroscopy to better understand nitrogen (N) cycling processes in forest plantations. In particular, the studies were designed to link to the effects of forest management practices and environmental conditions. 15N NMR cross polarization/magic angle spinning (CPMAS) and dipolar dephasing (DD)-CPMAS experiments of some simple N-containing compounds found widely in nature were first undertaken. This was done in order to understand how different sample conditions, such as the presence of moisture, sample mixing and dilution, affected the intensity and the observability of the NMR peaks corresponding to N containing functional groups. Our results exhibited changes in NMR signal intensities and various time constants calculated. In the case of variable contact time experiments, use of an equation that predicts both a bi-exponential rise and decay was found to fit the data obtained more accurately. The optimised parameters for 15N NMR CPMAS were then used along with other analytical techniques such as ion chromatography, total C and N and elemental analyses to study plant nutrient uptake, plant decomposition and the effect of forest ecosystem disturbances, in this case an insect infestation. These analytical data were also correlated with the changes in the 13C NMR spectra in order to gain a more comprehensive understanding of the chemical transformations in the forest ecosystem.

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George, Laurel. "Applications of solid-state 15N NMR spectroscopy to the study of nitrogen cycling in sub-tropical forest plantations." View thesis, 2008. http://handle.uws.edu.au:8081/1959.7/39262.

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Thesis (Ph.D.) -- University of Western Sydney, 2008.
A thesis submitted to the University of Western Sydney, College of Health and Science, School of Natural Sciences, in fulfilment of the requirements for the degree of Doctor of Philosophy. Includes bibliographical references.

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Almeida, Danilo Roberti Alves de. "Assessing tropical forest degradation and restoration through lidar remote sensing." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-20032019-162242/.

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The present study investigates new frontiers of lidar technology knowledge assessessing of tropical forest degradation and restoration. The thesis is structured with an introductory chapter, four technical chapters, which explored technical and scientific aspects of the application of lidar technology to the evaluation of forest degradation in the Amazon and restoration of forests in the Atlantic Forest, and a final chapter with considerations and a summary of the main scientific results obtained in this thesis. The results of chapter 2 provided important insights for the correct modeling of leaf area density (LAD) proflies profiles usind airborne lidar. LAD profile is the decomposition of the leaf area index (LAI) along the vertical canopy profile and can be used to answer many ecological questions. The results of chapter 2 provided important insights for the correct modeling of LAD profiles. Chapter 3, using lidar data on aerial and portable ground platforms, in the Biological Dynamics of Forest Fragments Project (BDFFP), demonstrated in an unprecedented way the effect of forest fragmentation in the canopy structure (lidar-derived) and their relationships with the change of the tree community. In this chapter, the results showed that the lidar technology has enormous potential to monitor the impact of forest fragmentation in a high precision scale for large areas. Chapter 4, using data from several forest typologies in the Atlantic Forest biome restoration collect by a portable ground lidar system, demonstrated the potential of canopy structural attributes to distinguish different forest typologies and to estimate above ground woody dry biomass. However, the results were not positive for estimating tree community diversity (richness, Shannon index and species composition). Finally, chapter 5 demonstrated the potential of a novel lidar system on a drone platform (also known as UAV - unmanned aerial vehicle) to monitor forest restoration plantations. Lidar is revolutionizing the way we measure forest landscapes and can be an indispensable tool for the success of forest restoration projects, having the potential to support on planning, monitoring and inspection of forest restoration landscapes. In this thesis, we demonstrate several applications of remote sensing to address the context of forest restoration, and we established methodological bases for other studies to expand the use of this technology for decision making in tropical forest conservation, management and restoration.
O presente estudo investiga novas fronteiras do conhecimento da aplicação da tecnologia de sensoriamento remoto lidar à avaliação da degradação e restauração de florestas tropicais. A tese está estruturada na forma de um capítulo de introdução, quatro capítulos técnicos, que exploraram aspectos técnicos e científicos da aplicação da tecnologia lidar à avaliação da degradação de florestas na Amazônia e restauração de florestas na Mata Atlântica, e de um capítulo final com considerações gerais e uma síntese dos principais resultados científicos obtidos nesta tese. O capítulo 2, utilizando dados lidar aeroembarcados em avião, analisou uma questão técnica, sobre a influência da densidade de pulsos da nuvem lidar e da resolução de amostragem para a modelagem do perfil de densidade de áerea foliar em florestas tropicais (DAF). O perfil de DAF é a decomposição do índice de área foliar (IAF) ao longo do perfil vertical do dossel e pode ser utilizado para responder diversas questões ecológicas. Os resultados da capítulo 2 trouxeram importantes insights para a correta modelagem dos perfis de DAF. O capítulo 3, utilizando dados lidar em plataformas aeroembarcados e terrestre portátil, no Projeto Dinâmica Biologica de Fragmentos Florestais (PDBFF), demonstrou de maneira inédita o efeito da fragmentação florestal sobre a alteração da estrutura do dossel (derivados de dados lidar) e suas relações com a mudança da comunidade arbórea. Neste capítulo os resultados demonstraram que a tecnologia lidar tem enorme potencial para monitorar o impacto da fragmentação florestal para grandes áreas e em fina escala. O capítulo 4, utilizando dados de diversas tipologias florestais em restauração no bioma Mata Atlântica, a partir de um sistema lidar terrestre portátil, demonstrou a capacidade dos atributos estruturais do dossel em distinguir diferentes tipologias florestais, estimar diversidade e biomassa de madeira acima do solo. Contudo, os resultados não foram muito positivos para estimativa da diversidade da comunidade arbórea (riqueza, indice de Shannon e composição de espécies). Finalmente, o capitulo 5 demonstrou a capacidade de um sistema inovador lidar aeroembarcado em uma plataforma drone (também conhecida como VANT - veículo aéreo não tripulado) para monitorar plantios de restauração florestal. O lidar está revolucionando a maneira de mensurarmos as paisagens florestais, podendo ser uma ferramenta imprecindível para o sucesso dos projetos de restauração florestal em larga escala, tendo o potencial de auxiliar desde o planejamento ao monitoramento e fiscalização dos projetos florestais. Nesta tese, demonstramos diversas aplicações do sensoriamento remoto lidar ao contexto da restauração florestal, e estabelecemos bases metodológicas para que outros estudos expandam o uso desta tecnologia para tomada de decisão na conservação, manejo e restauração de florestas tropicias.

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Brockmeyer, Berit [Verfasser], and Kay-Christian [Akademischer Betreuer] Emeis. "Dissolved and colloidal organic matter in a tropical lagoon-estuary system surrounded by sugar cane plantations / Berit Brockmeyer. Betreuer: Kay-Christian Emeis." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2011. http://d-nb.info/102045718X/34.

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Bossu, Julie. "Potentiel de Bagassa guianensis et Cordia alliodora pour la plantation en zone tropicale : Description d'une stratégie de croissance optimale alliant vitesse de croissance et qualité du bois." Thesis, Guyane, 2015. http://www.theses.fr/2015YANE0002/document.

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La ressource forestière en Guyane occupe une place maîtresse au sein de la région et est encore majoritairement préservée, mais la filière bois parvient difficilement à valoriser la biodiversité locale en raison de l’hétérogénéité de la ressource. Identifier les essences à planter demain représente aujourd’hui un enjeu à la fois environnemental, économique et social pour la Guyane. Bagassa guianensis Aubl. et Cordia alliodora (Ruiz & Pav.) Oken. vont à l’encontre des modèles usuels en associant vitesse de croissance et qualité du bois et sont identifiées comme prometteuses pour la plantation. Dans un premier temps, l’étude de la dynamique de croissance des deux espèces révèle un modèle écologique singulier, à la fois pionnières et longévives. La variabilité de l’infradensité dans l’arbre est l’élément clé qui permet un tel développement, favorisant une croissance rapide dans les premières années tout en assurant la longévité de l’individu. Dans une seconde partie, l’analyse d’un large panel de propriétés du bois (retrait, module, durabilité) en lien avec le développement de l’arbre confirme les qualités technologiques des deux espèces et permet l’émergence de résultats novateurs tels que le rôle des extractibles sur le retrait, le contrôle de la croissance grâce aux variations d’infradensité, l’évolution des traits foliaires au cours de l’ontogénie ou encore la mise en place de contrefil dans l’arbre pour assurer son maintien. La connaissance acquise vis-à-vis du mode de développement de ces deux espèces et des facteurs influençant la qualité de leur bois permet aujourd’hui de définir avec plus de précision le cadre d’un projet de plantation et les conditions de son succès. Les résultats de cette étude permettent finalement d’orienter la recherche de nouvelles espèces d’avenir pour la plantation en Guyane
The forests of French Guiana occupy a central part of the region’s potential resource base, but as yet remain almost completely unexploited. This stems from the forestry industry struggling to valorize wood stocks of a high diversity with an extremely heterogeneous distribution. Indeed, identifying essences for future propagation is an issue of both environmental and socio-economic importance for the region. Bagassa guianensis Aubl. and Cordia alliodora (Ruiz & Pav.) Oken. go against conventional models, in that they display the life history characteristics of rapid growth and wood of high quality, and thus are species of high potential for future plantations. Firstly, our study of growth characteristics reveals a defined strategy half way between long-lived species and pioneer species. It is the variability of basic density of wood which is a key trait allowing for such a development, favoring rapid growth in initial years whilst allowing for tree longevity. Secondly, the analysis of a range of wood properties (shrinkage, modulus of elasticity, durability) in relation to tree growth confirms the technologic quality of the two species. It also enables the emergence of new results like the effect of extractives on wood stability, the control of growth as a result of basic density variation, the evolution of leaf traits throughout tree development or the improvement of trunk maintenance thanks to interlocked grain. The knowledge gained in relation to the developmental traits of these two species, and to the quality of their wood allows for the elaboration of plantation projects and what will be required for their success. The results of this study can orientate future studies on novel species for commercialization in French Guiana

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Hackman, Richard Leonard. "Soil erosion and nutrient dynamics in tropical mahogany (Swietenia macrophylla) and acacia (Acacia mangium) forest plantations of the Caratal Watershed, St. Vincent, West Indies." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ38588.pdf.

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Pinheiro, Rafael Costa. "Avaliação da distância máxima de absorção de nutrientes em formações florestais tropicais usando 15N como marcador /." Botucatu, 2019. http://hdl.handle.net/11449/192690.

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Orientador: Jean-Paul Laclau
Resumo: As mudanças climáticas têm causado alterações na temperatura e também nos regimes de precipitação do planeta, aumentando a probabilidade de ocorrência de secas mais severas, o que, no cenário florestal, pode resultar na mortalidade de florestas ao redor do mundo. Assim, é necessário um conhecimento mais detalhado sobre a dinâmica de absorção de água e nitratos pelas raízes das árvores, que explique o comportamento das árvores sob extrema seca. O objetivo do estudo foi avaliar a distância máxima do tronco e a profundidade máxima de absorção de nutrientes e água pelas raízes das árvores em florestas crescendo sobre Neossolos Quartzarênicos muito profundos, utilizando o 15N como marcador. As consequências do status social das árvores, comparando árvores dominantes e dominadas do mesmo genótipo numa floresta monoclonal foram estudadas em plantios de um clone híbrido de Eucalyptus urophylla x Eucalyptus grandis durante a estação seca. Os efeitos da sazonalidade (comparando as estações seca e chuvosa) foram estudados em três espécies do Cerrado: i) Xylopia aromatica (Lam.) Mart.; ii) Coussarea hydrangeifolia (Benth.) Müll.Arg.; and iii) Miconia albicans (Sw.) Steud. Além disso, foi avaliada a existência de uma complementaridade de nicho no solo entre essas espécies do Cerrado, com uma absorção do marcador em camadas diferentes. O marcador NO3--15N foi aplicado em talhões de eucalipto com 7 meses, 1,2 anos, 2,2 anos e 6,4 anos de idade, a várias profundidades do solo em 60 pontos, s... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor

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Krause, Alena [Verfasser]. "Changes in trophic niches of oribatid mites with transformation of tropical rainforest systems - from rainforest into rubber and oil palm plantations in Sumatra, Indonesia / Alena Krause." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://d-nb.info/1224681703/34.

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Zhou, Jia. "Application de l'identification d'objets sur images à l'étude de canopées de peuplements forestiers tropicaux : cas des plantations d'Eucalyptus et des mangroves." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2012. http://tel.archives-ouvertes.fr/tel-00763706.

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La thèse s'inscrit dans l'étude de la structuration des forêts à partir des propriétés de la canopée telles que décrites par la distribution spatiale ou la taille des houppiers des arbres dominants. L'approche suivie est fondée sur la théorie des Processus Ponctuels Marqués (PPM) qui permet de modéliser ces houppiers comme des disques sur images considérées comme un espace 2D. Le travail a consisté à évaluer le potentiel des PPM pour détecter automatiquement les houppiers d'arbres dans des images optiques de très résolution spatiale acquises sur des forêts de mangroves et des plantations d'Eucalyptus. Pour les mangroves, nous avons également travaillé sur des images simulées de réflectance et des données Lidar. Différentes adaptations (paramétrage, modèles d'énergie) de la méthode de PPM ont été testées et comparées grâce à des indices quantitatifs de comparaison entre résultats de la détection et références de positionnement issues du terrain, de photo-interprétation ou de maquettes forestières. Dans le cas des mangroves, les tailles de houppier estimées par détection restent cohérentes avec les sorties des modèles allométriques disponibles. Les résultats thématiques indiquent que la détection par PPM permet de cartographier dans une jeune plantation d'Eucalyptus la densité locale d'arbres dont la taille des houppiers est proche de la résolution spatiale de l'image (0.5m). Cependant, la qualité de la détection diminue quand le couvert se complexifie. Ce travail dresse plusieurs pistes de recherche tant mathématique, comme la prise en compte des objets de forme complexe, que thématiques, comme l'apport des informations forestières à des échelles pertinentes pour la mise au point de méthodes de télédétection.

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Zhou, Jia. "Application de l’identification d’objets sur images à l’étude de canopées de peuplements forestiers tropicaux : cas des plantations d'Eucalyptus et des mangroves." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20214/document.

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La thèse s'inscrit dans l'étude de la structuration des forêts à partir des propriétés de la canopée telles que décrites par la distribution spatiale ou la taille des houppiers des arbres dominants. L'approche suivie est fondée sur la théorie des Processus Ponctuels Marqués (PPM) qui permet de modéliser ces houppiers comme des disques sur images considérées comme un espace 2D. Le travail a consisté à évaluer le potentiel des PPM pour détecter automatiquement les houppiers d'arbres dans des images optiques de très résolution spatiale acquises sur des forêts de mangroves et des plantations d'Eucalyptus. Pour les mangroves, nous avons également travaillé sur des images simulées de réflectance et des données Lidar. Différentes adaptations (paramétrage, modèles d'énergie) de la méthode de PPM ont été testées et comparées grâce à des indices quantitatifs de comparaison entre résultats de la détection et références de positionnement issues du terrain, de photo-interprétation ou de maquettes forestières.Dans le cas des mangroves, les tailles de houppier estimées par détection restent cohérentes avec les sorties des modèles allométriques disponibles. Les résultats thématiques indiquent que la détection par PPM permet de cartographier dans une jeune plantation d'Eucalyptus la densité locale d'arbres dont la taille des houppiers est proche de la résolution spatiale de l'image (0.5m). Cependant, la qualité de la détection diminue quand le couvert se complexifie. Ce travail dresse plusieurs pistes de recherche tant mathématique, comme la prise en compte des objets de forme complexe, que thématiques, comme l'apport des informations forestières à des échelles pertinentes pour la mise au point de méthodes de télédétection
This PhD work aims at providing information on the forest structure through the analysis of canopy properties as described by the spatial distribution and the crown size of dominant trees. Our approach is based on the Marked Point Processes (MPP) theory, which allows modeling tree crowns observed in remote sensing images by discs belonging a two dimensional space. The potential of MPP to detect the trees crowns automatically is evaluated by using very high spatial resolution optical satellite images of both Eucalyptus plantations and mangrove forest. Lidar and simulated reflectance images are also analyzed for the mangrove application. Different adaptations (parameter settings, energy models) of the MPP method are tested and compared through the development of quantitative indices that allow comparison between detection results and tree references derived from the field, photo-interpretation or the forest mockups.In the case of mangroves, the estimated crown sizes from detections are consistent with the outputs from the available allometric models. Other results indicate that tree detection by MPP allows mapping, the local density of trees of young Eucalyptus plantations even if crown size is close to the image spatial resolution (0.5m). However, the quality of detection by MPP decreases with canopy closeness. To improve the results, further work may involve MPP detection using objects with finer shapes and forest data measurements collected at the tree plant scale

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Versini, Antoine. "Effet de la manipulation des litières aériennes sur les cycles du C et de N dans les sols en plantation d'Eucalyptus au Congo." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0240/document.

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Ces dernières décennies, les plantations à croissance rapide sont apparues comme un moyen de répondre à la demande croissante en produits forestiers ligneux et comme une alternative à l'exploitation des forêts naturelles en zone tropicale. Un enjeu majeur est aujourd'hui de garantir la durabilité de ces plantations souvent installées sur sols pauvres et avec de fortes exportations de biomasse tous les 6-7 ans. Les litières présentes à la surface des sols peuvent jouer un rôle crucial sur la fertilité minérale et organique des sols qui conditionnent la productivité à court et long terme de ces écosystèmes tropicaux. L'objectif de ce travail était de comprendre par quels mécanismes le retrait ou l'ajout de litières influencent le développement de plantations d'Eucalyptus. En parallèle de mesures de croissance des arbres, la dynamique de minéralisation d'azote (N) au cours de la décomposition des rémanents a fait l'objet de plusieurs expérimentations. Les flux de nutriments en solution ont été comparés aux stocks initiaux dans les différents compartiments de l'écosystème et à la minéralomasse des arbres à la fin de l'étude. Un bilan de recouvrement de 15N apporté sous forme de rémanents lors de la plantation a été réalisé à l'échelle de la plantation. L'impact de la manipulation des litières sur les stocks de MO du sol a été évalué à partir d'analyses de sol ainsi que d'un partitionnement complet des sources de CO2 émis à la surface du sol. Les résultats de cette thèse montrent que la rétention des rémanents doit être optimisée et l'exportation de biomasse ligneuse compensée par l'apport de fertilisants, la pratique du brûlage doit être prohibée et les feux sauvages évités
In the last decades, fast-growing plantations have emerged as an important option to supply a growing share of the increasing demand for woody forest products and as an alternative to reduce the pressure on tropical rainforests. A major stake is nowadays to ensure the sustainability of these plantations often established on poor soils with large amounts of biomass exported every 6-7 years. Aboveground litters may play a crucial role on the mineral and the organic soil fertility which drive short- and long-term productivity in these tropical ecosystems. The main objective of our study was to identify the mechanisms involved in the Eucalyptus growth response to aboveground litter removal or addition over the two first years after planting. Apart from measurements of tree growth, the dynamic of nitrogen (N) mineralization in decomposing harvest residues has been studied in several experiments. Nutrient fluxes in soil solutions were compared to nutrient stocks initially contained in ecosystem compartments and to nutrient content within trees at age two years. A complete recovery budget of 15N brought within residues at the harvest was made at the stand scale. The long-term impact of aboveground litter manipulations on soil OM stocks was also assessed. Standard soil analyses (C&N) as well as a complete partitioning of soil CO2 efflux were carried out. The qualitative and quantitative dynamics of dissolved OM received special attention. The results show that the rapid release of potassium and the more progressive release of N contained in aboveground litter largely explain tree growth differences observed among OM management treatments. Eucalyptus tree considerably benefit from the nutrient released throughout litter decomposition since losses by deep drainage were very low as a consequence of soil depth and of the very fast development of roots both in the deep soil layers and in the organic layer. Our study also highlighted the large contribution of the topsoil OM (0-15 cm) for the production of nitrate and dissolved OM in gravitational soil solutions. The use of 15N labelling demonstrated that N is initially retained within the organic layer probably by microbial immobilization; transferred in simultaneous and balanced ways between organic residues components (leaves, barks and branches); and finally transported in particulate OM toward the mineral topsoil layer by gravitational water, supplying thus the soil OM pool on which the soil fertility relies. The retention of aboveground litter contributed to maintain soil OM stocks after the clear-cutting while its removal led to an initial decrease in soil OM stocks at the beginning of the rotation, which seemed to be balanced thereafter by litterfall inputs. The addition of litter led to an increase in dissolved OM fluxes in the first 15 centimeters of the soil profile which remained insignificant in comparison with soil OM stocks and exhibited low interactions with soil OM. Despite the rapid recovery of the soil OM pool, some nutrients might limit the productivity of these plantations after several rotations, as a result of repeated biomass exportation. Consequently, the retention of organic residues at the harvest should be optimized and the exportation of woody biomass must be compensated by fertiliser addition, burning of organic residues must be prohibited and wild fires prevented

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Röll, Alexander Verfasser], Dirk [Akademischer Betreuer] [Hölscher, Alexander [Akademischer Betreuer] Knohl, and Christoph [Akademischer Betreuer] Leuschner. "Changes in eco-hydrological functioning after tropical rainforest transformation to rubber and oil palm plantations / Alexander Röll. Betreuer: Dirk Hölscher. Gutachter: Dirk Hölscher ; Alexander Knohl ; Christoph Leuschner." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2015. http://d-nb.info/1077648510/34.

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Szulecka, Julia [Verfasser], Jürgen [Akademischer Betreuer] Pretzsch, Davide [Akademischer Betreuer] Pettenella, Laura [Akademischer Betreuer] Secco, Krystof [Akademischer Betreuer] Obidzinski, and Davide [Akademischer Betreuer] Petenella. "Changing Paradigms in a Changing Climate : Analyzing the Political Economy of Tropical Forest Plantations / Julia Szulecka. Betreuer: Jürgen Pretzsch ; Davide Pettenella ; Laura Secco ; Krystof Obidzinski. Gutachter: Jürgen Pretzsch ; Davide Petenella ; Krystof Obidzinski." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://d-nb.info/1079468188/34.

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Komba, Mayossa Prune Christobelle. "Dégradation du couvert forestier liée à la culture du palmier à huile par télédétection en milieu tropical humide : application au bassin du Congo." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0414.

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L’objectif de cette thèse est d’étudier la dégradation du couvert forestier liée à la culture industrielle du palmier à huile par télédétection dans le bassin du Congo, particulièrement la palmeraie de la SOCAPALM-Kienké au Cameroun. Pour caractériser la dégradation, afin de mettre en évidence le lien systémique existant entre la dégradation du couvert forestier et l’évolution de la palmeraie et de la structure paysagère, l’approche fonctionnelle de l’écologie du paysage a été couplée à l’approche spatiale de la télédétection. Pour atteindre cet objectif, plusieurs traitements intégrant des indicateurs spectraux, des indicateurs statistiques, des indicateurs structuraux de l’écologie du paysage et des indicateurs morphologiques de télédétection ont été effectués
The objective of this doctoral research is to study the degradation of forest cover due to the industrial cultivation of oil palm by remote sensing in the Congo Basin, particularly the SOCAPALM-Kienké palm grove in Cameroon. To characterize degradation, in order to highlight the systemic link between forest cover degradation and changes in palm grove and landscape structure, the functional approach to landscape ecology was combined with the spatial approach to remote sensing. To achieve this objective, several processing integrating spectral indicators, statistical indicators, structural landscape ecology indicators and remote sensing morphological indicators were carried out

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Zaremski, Clara. "Pour une production contrôlée d’agarwood d’Aquilaria crassna Pierre ex Lecomte en Guyane : Approches métagénomique, biochimique et histologique A review of the conditions of worldwide agarwood production and development prospects in French Guiana Caractérisation des communautés fongiques associées à Aquilaria Crassna Pierre ex Lecomte en plantation en Guyane française Composition chimique de l'agarwood d'aquilaria Crassna Pierre Ex. Lecomte des plantations de Guyane, en fonction du mode d'induction Détection rapide de l'agarwood et évaluation de sa composition chimique par spectrométrie proche infrarouge (SPIR) Etude histologique des cals d'aquilaria crassna colonisés par les champignons lignivores pycnoporus sanguineus gloeophyllum trabeum et antrodia vaillantii." Thesis, Guyane, 2020. http://www.theses.fr/2020YANE0002.

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Les arbres du genre Aquilaria Lam. (Thymelaeaceae), en réaction à un stress mécanique, produisent, en interactions avec des micro-organismes, un bois transformé par sa forte teneur en composés secondaires : l’agarwood (AW). Il est apprécié en parfumerie pour son odeur boisée. Face à la forte demande mondiale, des agriculteurs ont réalisé des plantations expérimentales d’Aquilaria en Guyane (projet Aquil@Guyane) afin de produire une huile essentielle de composition chimique contrôlée, respectueuse de la biologie de l’arbre et de l’environnement. Dans ce contexte, nous avons produit des connaissances académiques pour contribuer au développement de la production d’AW d’Aquilaria crassna en Guyane. Après caractérisation des communautés fongiques présentes dans les arbres d’A. crassna en Guyane, révélant le rôle des Basidiomycètes dans la production d’AW, deux méthodes d’induction d’AW ont été comparées : 1- levée d’écorce et application du sol de la plantation sur la blessure ; 2- inoculation de souches guyanaises de Basidiomycètes. Cette dernière est la plus efficace pour obtenir un AW de qualité proche d’un AW de référence. La Spectrométrie Proche Infrarouge (SPIR) a été utilisée pour différencier le bois sain de l’AW et différentes compositions chimiques d’AW. Les résultats obtenus sont cohérents avec ceux de l’analyse biochimique après hydrodistillation : utiliser la SPIR pour trier et contrôler la qualité de l’AW est envisageable. Une méthode de culture de cals d’Aquilaria a été mise au point pour comprendre les mécanismes moléculaires de la production d’AW. Les résultats indiquent une production de terpènes par les cals d’Aquilaria inoculés par des souches fongiques
Trees of the genus Aquilaria Lam. (Thymelaeaceae) in response to mechanical stress produce, in interaction with microorganisms, a wood transformed by its high content of secondary compounds: agarwood (AW). It is appreciated in perfumery for its woody fragrance. Faced with strong global demand, farmers have carried out experimental plantations of Aquilaria in French Guiana (Aquil@Guyane project) in order to produce an essential oil with a controlled chemical composition, respectful of the biology of the tree and the environment. In this context, we have produced academic knowledge to contribute to the development of AW production of Aquilaria crassna in French Guiana. After characterization of the fungal communities present in A. crassna trees in French Guiana, revealing the role of Basidiomycetes in the production of AW, two methods of induction of AW were compared: 1- lifting of bark and application of the soil of the plantation on the wound; 2- inoculation of Guyanese strains of Basidiomycetes. The latter is the most effective for obtaining a quality AW close to a reference AW. Near Infrared Spectrometry (NIRS) has been used to differentiate healthy wood from AW and different chemical compositions of AW. The results obtained are consistent with those of the biochemical analysis after hydrodistillation: using NIRS to sort and control the quality of AW is possible. An Aquilaria callus culture method has been developed to understand the molecular mechanisms of AW production. The results indicate the production of terpenes by Aquilaria callus inoculated with fungal strains

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Koks, Josephus [Verfasser], Edzo [Akademischer Betreuer] Veldkamp, Alexander [Gutachter] Knohl, and Heinz [Gutachter] Flessa. "Tropical forest conversion to rubber and oil palm plantations: landscape-scale and inter-annual variability of soil greenhouse gas (GHG) fluxes and the contribution of tree-stem emissions to the soil GHG budget in Jambi province, Sumatra, Indonesia / Josephus Koks ; Gutachter: Alexander Knohl, Heinz Flessa ; Betreuer: Edzo Veldkamp." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1213096316/34.

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Bourdier, Karen. "Vie quotidienne et conditions sanitaires sur les grandes habitations sucrières du nord de Saint-Domingue à la veille de l'insurrection d'août 1791." Pau, 2005. http://www.theses.fr/2005PAUU1006.

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Août 1791, l'insurrection des esclaves éclate en Haïti, encore appelée Saint-Domingue. Les années qui la précèdent sont le théâtre "privilégié" de l'apogée des habitations sucrières et avec elles celle de l'esclavagisme. Les conditions de vie et l'état sanitaire de ces esclaves, mais aussi des "cadres blancs" de quelques grandes sucreries connues, nous rapprochent de l'état physique et psychologique de ces hommes à la veille de l'insurrection. La santé est indispensable au bon rendement d'une habitation. Au sein d'une société fortement hiérarchisée, toute une organisation se met en place. A travers leur cadre de vie, leurs conditions de travail et les différents systèmes de soins rencontrés au sein de ces habitations, nous pouvons mieux comprendre le quotidien, les traitements infligés ainsi que les réactions, maladies et accidents qui en résultent. S'il semble que les conditions de vie et l'état sanitaire de tous et particulièrement des esclaves tendent à s'améliorer vers la fin du 18e siècle, essentiellement sur certaines grandes sucreries structurées du nord comme celles appartenant au marquis de Gallifet, comment expliquer que les premiers esclaves insurgés en août 1791 vivaient sur ces mêmes habitations ? Ne disait-on pas "heureux comme nègre à Gallifet" ?
August 1791, the insurrection of the slaves bursts in Haïti, still called Saint-Domingue. The years wich precede it are the "privileged" theatre of the apogee of the sugar plantations and wich them that of the slavery. The living conditions and the medical state of these slaves, but also of the "white executives" of some large known sugar plantations, bring us closer to the physical and psychological state of these men on the eve of the insurrection. Health is essential for the good productivity of a plantation. Within a strongly hierarchical society, a whole organisation is set up. Through their living environment, their working conditions and the various systems of care found within these plantations, we can better understand the everyday life, the treatments inflicted, as well as the reactions, diseases and accidents wich result from them. If it seems that the living conditions and the medical state of all and particularly of the slaves, tend to improve towards the end of the 18e century, and primarly on certain large structured sugar plantations of the north like those pertaining to the marquis de Gallifet, how to explain that the first slaves rebelled in August 1791 lived on these same properties ? Didn't one say "happy as a negro at Gallifet's" ?

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Page, DE. "Basidiospores : their influence on our thinking regarding management of Ganoderma root-rot disease in tropical hardwood plantation crops." Thesis, 2020. https://eprints.utas.edu.au/35192/1/Page_whole_thesis.pdf.

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Forest products are a major source of national revenue in Indonesia. Nearly 33% (69.9 million ha) of the country’s land area includes production forests. Several Acacia species are planted mainly for pulp production. By 2014 the total area of hardwood plantations established in this country was reported as approximately 1.2 M hectares with 600,000 ha of Acacia mangium. However due to susceptibility to two diseases (Ganoderma philippii and Ceratocystis manginecans) the A. mangium has been replaced by less susceptible eucalypts. By the early 2000s it was acknowledged that G. philippii, a basidiomycete root rot pathogen, was causing serious damage to A. mangium. In Central Sumatra, by the third rotation, several sites were found to be no longer capable of providing a commercial yield at harvest. Root diseases caused by basidiomycetes are among the most studied diseases of trees in the world, in particular for the genera Armillaria and Heterobasidion. Much can be inferred from those studies for G. phillipii but very little has been substantiated. The ability to trade-off concepts such as disease risk with the cost, effectiveness and deployment of various management strategies will depend on how well the pathosystem is understood and the context imposed by the particular cropping system and commercial environment. The main objective of the present study was to define fundamental aspects of G. philippii disease biology and aetiology (such as sexuality, gene flow and capacity for genetic variation, population dynamics) in order to ascertain the importance of basidiospores in disease dispersal and incidence. The study comprised three experimental investigations of; (1) G. philippii basidiospore germination, (2) G. philippii breeding systems, and (3) population structures of G. philippii in acacia plantations. Two other saprophytic Ganoderma species that are frequently found fruiting in Acacia and Eucalyptus plantations were included in the first two studies, for comparison with G. philippii. Spores were collected opportunistically and non-destructively from fresh basidiocarps emanating from the stems of mature-aged trees. Microscopic observations and empirical mathematical modelling enabled a description of the germination dynamics of the basidiospores of G. philippii, G. mastoporum and G. australe as influenced by factors such as spore density, simple or complex carbohydrate availability in the nutrient media, biotic carbon sources such as sawdust and/or ethanol media additives, and incubation temperature. This study is the first to describe simple, reliable protocols for in-vitro germination of G. philippii basidiospores. A standardised method for optimum axenic spore germination was described for each species. The germination dynamics of the basidiospores as observed in vitro were discussed in relation to their ecology. The sexuality and mating systems of G. philippii, G. mastoporum, and G. australe were determined. Observation of somatic interactions between monokaryotic and dikaryotic mycelia using genetically defined material confirmed the incompatibility mechanisms which operate to delimit individuals of these species in a population. Ten monokaryotic siblings; harvested as single spore isolates from each of two G. philippii, one G. mastoporum and two G. australe basidiocarps were paired in every possible combination. The macro- and micro-morphology and nuclear behaviour of interacting individuals were recorded at 7-day intervals. Ratios of ~1:4 compatible to incompatible crosses were observed between monokaryotic G. philippii, G. mastoporum, and G. australe siblings are consistent with ratios found for other Ganoderma species, indicating a tetrapolar mating system with alleles for heterothallism at two loci. The incidence and severity of red root disease increases with rotation. This may be linked to changes in the mode of dispersal of G. philippii, the balance between vegetative and spore dissemination. Preliminary somatic incompatibility tests indicated that genetic diversity increased with successive rotations implying an increasing, not decreasing role of spores. It was decided to further explore this observation with microsatellite analysis. Primers targeting microsatellite loci were screened against three isolates of G. philippii from geographically separate locations. All but two of the primer pairs successfully amplified G. philippii DNA, but the majority amplified a single product that did not vary among the test isolates. Eight of the primer sets were polymorphic and heterozygous in at least one of the test isolates. Populations were genetically distinct with high levels of inbreeding and clonal spread to adjacent trees increased after the first rotation. Despite the high levels of genetic diversity seen at all sampling scales, migration rates appear low. Measures to reduce the under-ground spread of the pathogen as well as methods to prevent the initiation of new infections from basidiospores will be needed to reduce the incidence of root rot in Acacia mangium plantations. The final chapter of the thesis reviews and discusses the significance of the above results in relation the hypothesis tested i.e. red root-rot disease, caused by G. philippii, predominantly occurs and spreads in tropical acacia plantations as a function of vegetative (clonal) infection pathways. The contribution of new information generated in this thesis to possible management strategies are discussed and recommendations are given for further research.

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Ciglasch, Holger [Verfasser]. "Insecticide dynamics in the soil environment of a tropical lychee plantation : a case study from Northern Thailand / von Holger Ciglasch." 2006. http://d-nb.info/980860342/34.

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Pryde, Elizabeth Clare. "Tropical production landscapes and conservation: a study investigating the biodiversity value of a native timber plantation landscape in Papua New Guinea." Thesis, 2014. https://researchonline.jcu.edu.au/43784/1/43784-pryde-2015-thesis.pdf.

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The majority of old-growth tropical forests and the vast biodiversity they support exist outside of protected areas, either embedded within production landscapes or adjacent to them. As a consequence, conserving the world's tropical biodiversity depends largely on the effective management of production landscapes (landscapes containing one or multiple production land-uses). Effective conservation management necessitates a balance between production goals (e.g. crop or timber yields) and biodiversity conservation. 'Land-sharing' strategies attempt to achieve this balance in production landscapes by encouraging lower-intensity production land-uses and where possible, the retention of pre-conversion vegetation cover. This presents a promising way forward for conservation in production areas but is hampered by inadequate information on the capacity of production landscapes to support native biodiversity in most tropical ecosystems. In this thesis I investigated the biodiversity conservation value of a multi-use production landscape comprised of native timber (Eucalyptus deglupta) plantations interspersed with (historically logged) secondary forests and unlogged forest remnants. The study was based in the lowlands of New Britain Island, Papua New Guinea and represents one of the only studies of the impact of production landscapes on Melanesian biota. To assess the state of biological diversity within this production landscape I had three principal objectives: (1) understand which forest species can and cannot persist in production land-uses and how these patterns are mediated by species' biological attributes; (2) evaluate the effect of land-use type on vegetation and stand-level structural attributes; and (3) examine which properties of the native plantation landscape most influence the occurrence patterns of lowland forest birds. Surveys were conducted at 156 survey sites over a two-year period (2007–2008). Sites were stratified among the five main management elements that comprised the plantation landscape and represented a gradient in land-use (from least-to-most disturbed): unlogged forest, secondary remnant forest, secondary riparian buffer strips, mature plantations and young plantations. At each survey site I recorded data on the occurrence of forest bird and tree species and measured the incidence of vegetation types and the stand structural attributes. Based on the knowledge gained from this research, I formulated conservation management strategies that can effectively balance the maintenance of forest biodiversity in the landscape with timber yield targets. Investigation into the patterns of forest species occurrence among landscape elements (the main land-use types) revealed that at least 70% of tree species and 90% of bird species were capable of existing outside of unlogged remnant forest, within the matrix of mature plantations and forestry-affected secondary forest. These levels are high compared to the tropical literature on timber plantations and suggest both a resilient species pool along with management practices that may encourage biodiversity retention. However, species richness at sites within mature plantations was lower than within unlogged and secondary forest and their species assemblages were compositionally dissimilar to those of unlogged forest, demonstrating a successive loss of more vulnerable species (e.g. late-successional trees, and frugivorous and forest-specialist birds). In addition, young plantations (2–6 years old) supported very few forest species and these species were in low abundance. These trends highlight the importance of considering the temporal as well as spatial aspects of production types when assessing conservation value. Evaluation of land-use effects on vegetation and habitat structure provided insight into both the post-disturbance recovery trajectory of the island's flora and the ramifications of this for their provision of potentially important habitat resources. In general, structural attributes recovered more rapidly than tree and plant species composition in the modified landscape elements. The secondary remnant forest, which was protected by a conservation reserve, demonstrated a very high regenerative capacity. By contrast, the unprotected secondary riparian element, which was subject to ongoing human disturbance and was of more linear shape and fragmented distribution, displayed simplified canopy structure and contained less late-successional vegetation. A similar but more extensive reduction in many old-growth habitat properties was observed for mature plantations, and young plantations suffered acute losses (and absences) for all habitat properties measured. Building on these findings, I examined the influence of both habitat properties and landscape spatial context on the species richness of forest birds. I found that habitat attributes (e.g. canopy cover and tree species richness) had a greater influence than spatial context (the proportion of unlogged and high-quality secondary forest within a 2km radius) on the richness of bird species among survey sites. In addition, for a sub-set of more vulnerable species (forest-specialists) I found palm cover to also be an important predictor of richness. These results further demonstrate the value of unlogged and secondary forest in terms of their quality as habitat for sustaining avifaunal populations, underscoring the need to formally protect these forests to achieve long-term biodiversity conservation benefits. These results also revealed the properties of mature plantations that facilitated visitation by forest birds and conversely drew attention to management practices that could negatively affect this relationship. The outcomes of this thesis indicate that land-sharing strategies incorporating production types such as native timber plantations, which permit high canopy cover and tree species richness, can be effective at balancing yield production with biodiversity conservation. Native species are used in <15% of tropical plantation forests globally and given their potential to deliver conservation outcomes, research should be directed at countering barriers to their use over exotic species. However, this study also concluded that such conservation outcomes are dependent on the sympathetic management of plantations, as well as land-use planning directed at facilitating the spatial and temporal continuity of old-growth forest features in the landscape. In addition, without the formal protection and careful management of unlogged and secondary forest reserves, the likelihood of long-term conservation of many forest-dependent species will diminish. Basing conservation management of production landscapes on scientific research is a vital but often unachievable undertaking in the tropics, particularly over the long-term. It is likely that the adoption of recommended management actions can be supported by more targeted research and importantly, through greater collaboration between research institutions, sustainable management organisations, land managers and local communities. Science can go a long way to assist with decision-making but ultimately decisions rest with the values of society.

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Szulecka, Julia. "Changing Paradigms in a Changing Climate: Analyzing the Political Economy of Tropical Forest Plantations." Doctoral thesis, 2014. https://tud.qucosa.de/id/qucosa%3A29049.

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Die vorliegende Studie analysiert die Politische Ökonomie von Forstplantagen in den Tropen. Die Analyse der Makroebene zeigt dabei eine globale Perspektive auf, sowie historische Veränderungen von Paradigmen in Bezug zu Waldplantagen. Der zweite Teil der Studie analysierte Plantagen auf der Mikro-Ebene im Hinblick auf divergente geographischen Zusammenhänge, nämlich Paraguay und Indonesien. Fallstudien eignen sich hierbei, um ein vielfältiges Spektrum von Waldplantagen darzustellen, sowie Beispiele für die in der Makroebene abgeleiteten Paradigmen zu illustrieren. Abschließend verbindet die Studie die Entwicklungen der Makro-Ebene mit Belegen aus der Mikro-Analyse. Hierauf ableitend werden Empfehlungen für die Anlage zukünftiger Plantagen getätigt. Die Methodik wurde den Untersuchungsebenen in einem iterativen Prozess angepasst. Der Umfang variiert dabei von Makro- bis Mikroanalysen, sowie vom theoretischen bis zum empirischen Niveau. Auf der Makroebene wurde eine Politische-Ökonomie-Analyse und eine Untersuchung desrelevanten historischen Materials durchgeführt. Weiterhin wurden Plantagen Paradigmen anhand ausgewählter Indikatoren abgegrenzt. Für die Mikroebene wurden Fallstudien mit lokalen Interviews durchgeführt, welche Daten für eine Mehrkriterienanalyse (MCA) lieferten. Die Kombination der Mikro- und Makroanalyse erfolgte durch eine Korrelationsanalyse und wurde durch eine Diskussion abgerundet. Das Forschungsergebnis aus der globalen Analyse ist eine Typologie von sechs Paradigmen und deren Untervarianten, welche als theoretisches und analytisches Werkzeug in der Forschung zu Plantagen dienen können. Die Paradigmen wurden klassifiziert als: i) das vorindustrielle P.; ii) das kolonial industrielle und national industrielle; iii) das Schutzparadigma; iv) das soziale P.; v) das neo-liberale und modifiziert neoliberale P. und vi) das globalpolitische Paradigma. Die Ergebnisse der Fallstudien und MCA zeigen zum einen sichtbare Mängel in Plantagen unter verschiedenen Paradigmen auf und unterstreichen zum anderen positive Effekte bestimmter Paradigmen. Die MCA Bewertungspunkte zeigen zum Beispiel, dass manche Paradigmen mit dem Kriterium Landkonflikt korrelieren, oder präsentieren unterschiedliche lokale Beteiligung auf verschiedenen Plantagen, illustrieren Vorteile, die Plantagen für unterschiedliche Interessengruppen bringen. Die MCA bewertet weiter die Wirtschaftsleistung der Plantagen und vergleicht Faktoren, wie Nutzenverteilung, Rentabilität, Marktzugang und Rahmenbedingungen für Investitionen. Sie analysiert soziale Faktoren, wie Arbeitssicherheit, Zugang zu Dienstleistungen, Beteiligung oder Personalmanagement. Weiterhin werden Umweltprobleme durch die Studie aufgegriffen, z.B. Landnutzungsänderungen, Wasser- oder Boden- Auswirkungen, Lebensraumfunktion usw. Wie die vergleichende Analyse zeigt, ist die modifizierte Neoliberale Paradigma Plantage (Outgrower-Scheme) besonders geeignet, um sowohl soziale als auch wirtschaftliche Vorteile zu sichern (90 % und 84 % in den entsprechenden Feldern gegenüber dem hypothetischen Idealtyp Plantage). Andere Forschungsergebnisse deuten auf wichtige Erkenntnisse bei der Plantagenentwicklung hin, die auf der Plantagen-Ebene und bei der Gestaltung nationaler Rahmenbedingungen für den Plantagensektor berücksichtigt werden sollten. Handlungsempfehlungen für die forstwirtschaftliche, epistemische Gemeinschaft zur Gestaltung der weiteren Diskurse in Bezug auf globalen Plantagen werden ebenfalls diskutiert.:CHAPTER 1 – INTRODUCTION AND RESEARCH DESIGN 1 1.1 Introduction: The Changing Climate for Plantations 1 1.2 Problems with defining forest plantations 4 1.3 Aim and structure of the study 6 1.4 Theory: Political Economic Approaches to Forestry 8 1.4.1 Political economy’s field of investigation 8 1.4.2 Applications to forestry research 12 1.4.3 Theoretical approach in this study 14 1.5 Research Design 18 1.5.1 Theoretical framework 18 1.5.2 Goals and Objectives of the study 20 CHAPTER 2 – METHODOLOGY 22 2.1 Overview of the methodology and data gathering techniques 22 2.2 Methodology in studying paradigm change 23 2.3 Methodology applied in case-studies 26 2.3.1 Case selection 26 2.3.2 Data gathering for the comparative multiple case-study and MCA 30 2.3.3 Questionnaire design 32 2.4 Methodological issues in integrating the levels 35 2.5 Methodology for alternative explanations to the paradigm concept 35 2.6 Research ethics 36 CHAPTER 3 – TROPICAL FOREST PLANTATIONS AND THE GLOBAL ECONOMY: FROM TIMBER TRADE TO CARBON OFFSETTING 37 3.1 Raw material for international markets 39 3.2 Adding value domestically: Shift in the role and scale of tropical plantations 42 3.3 From Rio until the present: Certification and carbon forestry? 46 3.4 Necessary expansion of plantations, uncertain impacts 50 3.5 From the political economy to the plantation paradigms 53 CHAPTER 4 – PLANTATION PARADIGMS AND A GLOBAL PERSPECTIVE ON FOREST PLANTATIONS 55 4.1 Roots and applications of the concept of a paradigm in forestry 55 4.2 Global political and social context for plantation forestry 57 4.3 Typology of Plantation Paradigms 60 4.4 Empirical application of the paradigm typology 69 4.4.1 Country Case I: Paradigms and the development of plantations in Paraguay 69 4.4.2 Country Case II: Paradigms and the development of plantations in Indonesia 73 CHAPTER 5 – PLANTATIONS FROM A LOCAL PERSPECTIVE: CASE STUDIES OF SELECTED PLANTATIONS FROM PARAGUAY AND INDONESIA 84 5.1 Plantation case studies in Paraguay 84 5.1.1 Case study I: Smallholder plantation with development aid, San Pedro Department 84 5.1.2 Case study II: Smallholder plantation with Clean Development Mechanism (CDM), Paraguarí Department 86 5.1.3 Case study III: Out-grower schemes in Itapúa Department 88 5.1.4 Case study IV: Enterprise POMERA, Alto Parana Department 90 5.2 Plantation case studies in Indonesia 92 5.2.1 Case study V: Community plantation through Community Forest Owners Association APHR, Wonosobo Regency, Java 92 5.2.2 Case study VI: State enterprise Perum Perhutani, Randublatung Reg., Java 94 5.2.3 Case study VII: Enterprise Musi Hutan Persada (MHP), Muara Enim Regency, Sumatra 96 5.3 Multi-Criteria-Analysis of the plantation case studies 99 CHAPTER 6 – INTEGRATION AND DYNAMICS BETWEEN THE GLOBAL, NATIONAL, AND LOCAL LEVELS 104 6.1 Comparative analysis: Global paradigms and the local performance of selected plantations. Assumptions vs. Observations 104 6.1.1 Industrial national paradigm reflected in Case study VI (Perum Perhutani in Randublatung, Indonesia) 105 6.1.2 Social paradigm reflected in Case study I (PMRN in Paraguay) and Case study V (Community Forest Owners Association in Indonesia) 108 6.1.3 Neoliberal paradigm reflected in Case study IV (POMERA in Paraguay) and Case study VII (MHP in Indonesia) 111 6.1.4 Neoliberal modified paradigm reflected in Case study III (Out-grower scheme in Itapúa, Paraguay) 115 6.1.5 Global political paradigm reflected in Case study II (CDM in Paraguay) 118 6.2 Explaining divergences – on the unpredicted observations 121 6.3 Strengths and weaknesses of the studied paradigms 127 CHAPTER 7 – METHODOLOGICAL CHALLENGES AND ALTERNATIVE EXPLANATIONS 129 7.1 Methodological challenges of the paradigm approach 129 7.2 The paradigm concept and alternative explanations 130 7.3 Other limitations of the political economic research on plantations 133 7.3.1 Problem with reliable data and changing plantation definitions 134 7.3.2 Problems of explorative research 134 7.3.3 Problems with indicator setting 134 7.3.4 Problem of single-case study dominance 135 CHAPTER 8 – LESSONS LEARNED 136 8.1 Lessons from the global historical paradigm analysis 136 8.2 Lessons from the case studies 138 8.2.1 Paraguay 138 8.2.2 Indonesia 140 8.2.3 Best practices from the local plantation case studies 143 8.3 Conclusions 150 8.4 Outlook: The future political economy of tropical forest plantations 154 8.5 Next steps – identifying further research gaps and directions 155 REFERENCES 157 ANNEXES Annex to Chapter 3 178 3.1 Historical global plantations’ development with a focus on the species 178 Annex to Chapter 4 181 4.1 Word Forestry Congresses 1926-2009: Snapshots on key issues in forestry, tropical forestry and plantations 181 4.2 Changing plantation discourse: a content analysis of Unasylva 193 Annex to Chapter 5 199 5.1 Steps of the MCA analysis 199 5.1.1 Data normalization table 199 5.1.2 Clusters of indicators used in the data analysis 202 5.1.3 Final synthetic index 204 5.2 Questionnaires 204 Annex to Chapter 6 208 6.1 Detailed Comparative analysis: Global paradigms and the local performance of selected plantations. Assumptions vs. observations 208 6.1.1 Comparative figures 209 6.1.2 Comparative analysis according to the paradigms 217 6.1.3 Summary of confirmed and unobserved elements 235 6.1.4 Correlation analysis 236

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Bich, NV. "Inter-rotational strategies for sustaining site fertility and productivity of acacia and eucalyptus plantations planted on steep slopes in northern Vietnam." Thesis, 2019. https://eprints.utas.edu.au/31430/1/Bich_whole_thesis.pdf.

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In Vietnam, approximately 1.3 M ha of acacia and eucalypt plantations have been established in the past three decades to supply a growing local and international demand for pulp and sawlog. Wood production over successive rotations does not appear sustainable as yields are declining and soils, especially on steep sites, are being eroded and negatively impacted. There is concern that current practices, i.e. burning harvest residues and only applying a small dose of fertilisers at planting are in part responsible for this situation and need to be changed. This thesis examines if changes in the current practices i.e. the retention of harvest residues and increased P fertilisation will improve the soil properties and productivity of Eucalyptus hybrid (Eucalyptus urophylla × E. pellita) and Acacia mangium plantations planted on steep slopes in northern Vietnam. The first study investigated whether the decomposition of retained A. mangium harvest residues (branches, leaves and bark) could provide sufficient nutrients for the next rotation. The biomass and nutrient content of above-ground stand components of the previous 7-year-old Acacia mangium rotation were examined at harvest, and the rates of decomposition and nutrient release from the harvest residues determined. The decomposition constant k, half-life t0.5 and release of nutrients (N, P, K, Ca and Mg) were monitored by using the litterbag technique for a 1.5-year-period. At harvesting, the total above-ground stand biomass of the previous rotation was 60.8 t ha\(^{-1}\), comprising stemwood (42.7 t ha\(^{-1}\)), bark (8.9 t ha\(^{-1}\)), branches (6.6 t ha\(^{-1}\)) and leaves (2.5 t ha\(^{-1}\)). The retained bark on site made up one-third of the mass of all residues (harvest residues + litter + understorey vegetation) and conserved 6% Mg, 14% K, 18% P, 30% N and 41% Ca content for recycling. The decomposition rate of the leaves was the most rapid (k = 1.47 year\(^{-1}\); t0.5 = 0.47 year), then branches (k = 0.54 year\(^{-1}\); t0.5 = 1.29 year) and bark (k= 0.22 year\(^{-1}\); t0.5 = 3.09 year). During decomposition, the loss of nutrients from harvest residues was K ≈ Ca > N > P> Mg. Over 1.5 years of the study period, as much as 137.1 kg N ha\(^{-1}\), 4.7 kg P ha\(^{-1}\), 20.8 kg K ha\(^{-1}\), 94.5 kg Ca ha\(^{-1}\) and 2.2 kg Mg ha\(^{-1}\) were recycled. The N, Ca and K, though not P and Mg released from decomposing A. mangium harvest residues are potentially able to meet a significant part of the demand by trees growing in the next rotation. The second study examined whether the retention of residues, and application of phosphorus fertiliser at higher rates than the current practice, can increase rates of growth and vigour of trees, i.e. better tree form and lesser crown damage, of eucalypt and acacia plantations. A factorial combination of residue management (burning vs. retention) and phosphorus (P) fertiliser application at planting (15 vs. 100 kg ha\(^{-1}\)) treatments was applied at a steeply sloping site (slope rages from 8 – 40 ̊). Two adjacent experiments were established, one with A. mangium and the other with E. hybrid. Standing volume (V) and leaf area index (LAI) in A. mangium were greater following burning; this was mostly attributable to the significantly higher survival rate of seedlings. Burning of residues was associated with increases in the number of large branches per tree, and a higher crown damage index (CDI). In the E. hybrid, diameter and height responses to the higher rate of fertiliser were observed at age 6 and 12 months, but not beyond. High P application also led to higher CDI. Standard fertiliser treatment, applied in amounts equivalent to 17, 15 and 8 kg ha\(^{-1}\) of N, P, K, respectively, was adequate to meet the early growth requirement of eucalypt and acacia plantations at this site. The third study examined the effect of two contrasting harvest residue management treatments (burning vs. residue-retention) on soil properties i.e. soil total carbon (TC), total nitrogen (TN), extractable P (ext-P), exchangeable K (exch-K) and soil bulk density (BD) of E. hybrid and A. mangium plantations. In this study, soil samples were collected in plots treated with similar amounts of fertiliser (applied at the current rate) but subject to contrasting residue management treatments (burning vs. residue-retention). The soil properties were assessed at pre-establishment, and at age one and two years following planting. The results showed that the soil properties in either E. hybrid or A. mangium plantations were not significantly different between residue retention and residue burning inter-rotational treatments. However marked variations observed in soil TC, exch-K and ext-P suggest that position on the slope masked any overall trends. In summary, the relatively low amounts of harvest residues and high fertility levels at the site may be associated with the lack of significant growth and soil responses to the silvicultural treatments applied in this study. However, it is clear that the decomposition of harvest residues and the associated rate of nutrient release can supply a significant amount of nutrients required for stand development in the next rotation. The variation in standing volume, crown health and soil properties between slope positions suggest that factors driving any correlation of tree productivity with slope, for example surface run-off and soil erosion will need careful management to arrest potential yield decline on steeply sloping sites. Thus harvest residue retention with adequate weed and termite control may be preferential to burning on a steep slope because the residue not only can provide nutrients but reduce water run-off and soil erosion.

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Bastien-Henri, Sara. "Biomasse aérienne en plantations d'arbres tropicaux." Mémoire, 2008. http://www.archipel.uqam.ca/1833/1/M10726.pdf.

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La déforestation effectuée dans l'optique d'une récolte de bois par l'industrie forestière ou afin d'augmenter la superficie des champs pour l'agriculture est en constante progression dans le monde et amène bien des problèmes environnementaux qui passent de la dégradation du sol, à la diminution de la biodiversité et aux changements climatiques. Il est donc urgent de prendre les mesures qui s'imposent pour contrer ce problème. Une des solutions préconisées actuellement est l'établissement de plantation d'arbres pour le bénéfice de la restauration du sol et de la production commerciale de bois. Ce type de plantation, en région tropicale, est principalement effectué en monoculture d'espèces d'arbres exotiques. Au Panama, en 2003, 89% des arbres en plantation provenaient de quelques genres exotiques seulement. Il y a donc à craindre quant à l'impact sur la biodiversité de ce type de reforestation en plus de ne pas toujours être bien adapté aux conditions du milieu. Il y a donc encore beaucoup de recherche à faire afin de trouver des solutions pertinentes à ces problématiques. Le projet PRORENA est une vaste étude cherchant, par la plantation d'espèces indigènes du Panama, à développer les connaissances touchant les espèces indigènes et leurs comportements en plantation. Le cadre de ce projet était particulièrement intéressant pour effectuer une étude portant sur la caractérisation de la croissance de ces espèces afin de mieux connaître leur autoécologie. L'apport de connaissances dans ce domaine permettra d'aider les propriétaires terriens à faire un choix plus éclairé des espèces les plus intéressantes pour la reforestation en fonction des objectifs visés. Ce projet de recherche visait donc à déterminer l'allométrie de l'allocation de la biomasse des arbres afin de mieux connaître l'autoécologie des espèces étudiées. Nous cherchions donc à mieux comprendre où se dirigent les ressources des arbres afin de faire un choix d'espèces éclairé lors de l'installation d'une nouvelle plantation et dans quelles proportions cette allocation change en fonction de la taille des individus, mais aussi en fonction de l'environnement (disponibilité des ressources, principalement l'eau) et en fonction des groupes fonctionnels. Pour ce faire, la récolte destructive de la biomasse aérienne des arbres a été effectuée pour 21 espèces d'arbres indigènes et 2 espèces exotiques. Cet échantillonnage nous a permis de comparer l'accumulation totale de biomasse aérienne entre les espèces, de même que de comparer la croissance entre deux sites présentant un gradient de précipitation et de richesse du sol. Ce projet a aussi permis de comparer la distribution de la biomasse entre les feuilles, les branches et le tronc en fonction des espèces et des sites et de déterminer si une relation allométrique simple peut être établie entre la biomasse totale et des mesures de taille comme le diamètre à la base de l'arbre et la hauteur. Par ailleurs, le manque d'informations sur les traits fonctionnels des espèces étudiées ne nous a pas permis d'aborder le sujet lors des analyses. Le taux de croissance des arbres varie grandement entre les espèces. Pour le tiers des espèces étudiées, l'accumulation de la biomasse aérienne est plus rapide au site plus humide et permet de penser que pour ces espèces, le choix du site semble important afin d'obtenir une croissance optimale. Certaines espèces indigènes performent aussi bien, sinon mieux que les espèces exotiques étudiées. Il est important de noter que l'allocation de la biomasse aux racines n'a pas été étudiée. Il est fort probable que la longueur de la saison sèche à Rio Hato influence positivement la croissance racinaire au détriment de la croissance aérienne et qu'il soit possible d'observer ces différences au niveau des traits étudiés. L'étude des relations entre les ratios longueur de la couronne:diamètre de la couronne et longueur de la couronne:hauteur totale et la taille soulignent l'importance de retirer cet effet afin de comparer les sites principalement à cause de la présence d'espèces aux tailles très variées. Lorsque ces ratios sont corrigés, nous observons un effet de l'espèce très prononcé. Par ailleurs, ces traits qui diffèrent entre les sites pour certaines espèces sont plus grands à Soberania. Finalement, il y a une relation importante entre le diamètre à la base de l'arbre, mesure simple de croissance, et la biomasse totale ce qui permet de déterminer l'accumulation de la biomasse aérienne pour n'importe quelle espèce d'arbre dans des conditions environnementales très différentes en termes de précipitation et de richesse du sol au Panama. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Biomasse aérienne, Plantation d'arbres, Gradient de précipitation, Tropiques, Transformation d'Aitchison.

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Kabera, Isaac. "The role of forest plantations in the restoration of tropical forests." 2000. http://www.library.wisc.edu/databases/connect/dissertations.html.

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Dissertations / Theses on the topic 'Tropical plantation'

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