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Moreira, Jorge Felipe Quintana. "Uso de antraquinona en cocción kraft de Eucalyptus globulus y Eucalyptus nitens." Universidade Federal de Viçosa, 2011. http://locus.ufv.br/handle/123456789/5926.
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Previous issue date: 2011-07-19Foi analisada, experimentalmente, o efeito da adição de antraquinona ao processo kraft convencional para produção de celulose de mistura de Eucalyptus globulus e Eucalyptus nitens. Foram analisados aumentos da velocidade da reação de deslignificação e estabilidade dos carboidratos, utilizando condições industriais de cozimento batch da Celulosa Arauco y Constitucion SA, Planta Arauco. Para alcançar kappa constante (15 e 17) foram modificados os tempos de cozimentos e foram utilizadas diferentes dosagens de antraquinona. Foram estabelecidas relações lineares entre a dosagem de antraquinona e o rendimento depurado, o teor de rejeitos, o alcali residual e o teor de sólidos no licor residual. Para a dosagem máxima de AQ utilizada (0,10%) foram obtidos, para ambos os níveis de kappa, aumentos de 1,95% e 1,32% nos rendimentos depurados, economias de 14,2% e 50,4% nas cargas de álcali e decréscimos nos tempos de cozimento de 13 e 11 minutos para kappa 15 e 17, respectivamente.
En la presente disertación se verificó de manera experimental el efecto de la adición de Antraquinona al proceso de cocción batch convencional para una mezcla industrial de Eucalyptus globulus E. nitens.; en lo que respecta a su capacidad de aumentar la velocidad de la reacción de deslignificación y proporcionar estabilidad a las hemicelulosas y celulosas de la fibra. Lo anterior se logró con experiencias de laboratorio fijando las condiciones de cocción de acuerdo a la operación de los digestores batch de Celulosa Arauco y Constitución S.A., Planta Arauco. Donde para obtener un kappa constante (15 y 17) se modificó el Factor H mediante el tiempo de cocción, en distintos niveles de carga de Antraquinona. Se pudo establecer una relación lineal entre la dosificación de Antraquinona y los parámetros estudiados: rendimiento clasificado, rechazos, álcali residual, tiempo de cocción y sólidos en el licor negro. Particularmente, para la máxima dosificación de AQ utilizada en este estudio (0,1% bms) se obtuvo para ambos niveles de Kappa respecto al blanco o testigo- un aumento de 1.95% y 1.32 de rendimiento clasificado, un ahorro de álcali de 14.2% y 50.4% y una disminución de tiempo de cocción de 13 min y 11 min para Kappa 15 y 17, respectivamente.
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Pozo, Peñaloza Edmundo. "Efecto de la fertilización sobre plantaciones de Eucalyptus globulus (Labill.) y Eucalyptus nitens (Maiden) de siete años de edad en la Comuna de Máfil, Provincia de Valdivia." Tesis, Universidad de Chile, 2005. http://www.repositorio.uchile.cl/handle/2250/105059.
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Patrício, Helena Sofia Maurício. "Caracterização anatómica da casca de Eucalyptus nitens (Deane & Maiden) e Eucalyptus rudis Endl. para identificação das espécies." Master's thesis, ISA, 2014. http://hdl.handle.net/10400.5/6800.
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Mestrado em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de AgronomiaThe bark of 5 trees of E. nitens with 4 and 10 years of age, and 5 trees of E. rudis with 4 years of age was analyzed. The qualitative characterization and the determination of the tissue proportions were made on histological thin sections and quantitative characterization on dissociated elements; the dimension of fibres, axial parenchyma and expanded cells was also determined. The species showed: reduced rhytidome, periderm composed by phellem with suberised and lignified cells and phelloderm; non-collapsed phloem with tangential layers with axial parenchyma alternating with sieve tube elements and fibre bundles; the collapsed phloem is characterized by the change of the parenchyma cells and sclereids. The length, width and wall thickness of fibers was in 4-year-old E. nitens 0.90 mm; 16.2 μm and 4.7 μm; in 10-year-old E. nitens 1.05 mm; 17.8 μm and 5.2 μm and E. rudis 0.84 mm; 21 μm and 6 μm respectively. The expanded axial parenchyma cells are the most abundant phloem tissue (38-48%) in both species; the percentage of fibers was higher in E. nitens (33%). The species differed in the type of periderm, in the arrangement of the expanded cells and in the occurrence of secretory cavities.
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Antunes, Fernanda Schablatura. "Avaliação da qualidade da madeira das espécies Acacia crassicarpa, Acacia mangium, Eucalyptus nitens, Eucalyptus globulus e Populus tremuloides." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-23062009-094257/.
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As madeiras utilizadas para produção de polpa celulósica podem ser divididas em dois grupos em função da fibra: folhosas (fibra curta) e coníferas (fibra longas), as espécies de folhosas são destinadas especialmente a papéis de escrita e impressão. As principais espécies de folhosas utilizadas para produção de polpa de fibra curta em outros países são o Eucalyptus globulus (Península Ibérica e Chile), Eucalyptus nitens (Chile), Populus tremuloides (Canadá), Acacia mangium, Acacia crassicarpa (Indonésia). Este projeto tem por objetivo: avaliar e comparar o desempenho de madeiras utilizadas mundialmente para produção de polpa celulósica de fibra curta considerando parâmetros de qualidade da madeira tais como composição química, densidade básica, características anatômicas da madeira; com objetivo de fornecer informações estratégicas para o setor nacional de celulose e papel, visando o conhecimento e posicionamento em competitividade destas madeiras no mercado mundial. Para a realização deste trabalho foram coletadas 5 árvores de cada espécie as quais foram utilizados cavacos cortados manualmente obtidos de discos; com relação à madeira foram determinadas densidade básica, composição química e dimensões de fibras. Os resultados foram analisados estatisticamente sendo comparadas as diferentes espécies referentes à qualidade da madeira.Wood used for pulp production may be divided in two major groups regarding fiber function: hardwood (short fiber) and softwood (long fibers). Hardwood species are mainly designated to writing and printing papers. Hardwood principal species used for production of short fiber pulp in other countries are Eucalyptus globulus (Iberian Peninsula and Chile), Eucalyptus nitens (Chile), Populus tremuloides (Canada), Acacia mangium and Acacia crassicarpa (Indonesia). This study aimed to evaluate and compare the performance of the main woods used worldwide for short fiber pulp production regarding wood quality parameters such as chemical composition, basic density and wood anatomical properties, in order to provide strategic information for national pulp and paper industry, aiming the knowledge and competitiveness of these woods at worldwide market. To accomplish this study, 5 trees from each species were collected and wood chips were manually cut. In relation to the wood, basic density, chemical composition and fiber lengths were determined. The results were statistically analyzed and the different species were compared regarding wood quality.
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Degefu, Dawit Tesfaye. "Ecology and genetic diversity of Coryphodema tristis on Eucalyptus nitens in South Africa." Thesis, University of Pretoria, 2012. http://hdl.handle.net/2263/79225.
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Forests are complex ecosystems that provide a variety of valuable products, such as timber, fuel wood, fiber and non-wood forest products and they also contribute to socio economic development. Pest problems have a considerable influence on the health of planted and natural woodlands of this industry. Members of the family Cossidae are often of serious concern to forestry and horticulture due to their aggressive, often gregarious wood-boring behaviour. Some species of this family (e.g Coryphodema tristis and Chilecomadia valdiviana) is known to be highly polyphagous and members occupy diverse ecological zones. Coryphodema tristis and Chilecomadia valdiviana are examples of cossid species that have recently expanded their host range to include non-native species. Coryphodema tristis was first reported infesting the non-native plantation species, Eucalyptus nitens, in South Africa in 2004, and C. valdiviana was first recorded infesting the same species in Chile in 1992. These insects have been reported to cause substantial damage to E. nitens. Both species are associated with a number of native trees in their respective countries, as well as non-native fruit trees and ornamentals. Despite what appears to be extreme polyphagy in C. tristis, many trees, including many Eucalyptus species and even hybrids of E. nitens and E. grandis planted in the province of Mpumalanga, are apparently free of any cossid moth infestation. These novel host range expansions raise interesting questions regarding the factors that influence new host associations. This review examines Cossidae as pests in native and non-native forest systems. Possible factors contributing to success of Cossidae in forestry and control strategies employed to manage the group are discussed.Thesis (PhD)--University of Pretoria, 2014.
Genetics
PhD
Unrestricted
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Moscoso, Sergio Hernán Carreño. "Efecto del polisulfuros en la producción de pulpa Kraft de Pinus radiata y mezcla de Eucalyptus Globulus y Eucalyptus Nitens." Universidade Federal de Viçosa, 2011. http://locus.ufv.br/handle/123456789/5928.
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Previous issue date: 2011-12-06Este estudo visa determinar, através de laboratório convencionais cozimento kraft, os efeitos da adição de polissulfeto no desempenho da celulose, hemicelulose, matéria orgânica do licor negro e físico-mecânicas da polpa, e entregar recomendações para testes na Constituição planta industrial, que tem um processo RDH. Os resultados mostram aumento no desempenho em relação ao de referência, 3,2% e 8,5% em Pinus radiata e 1,3% e 3,4% em Eucalyptus (mistura de 70% e 30% Eucalyptus nitens Eucalyptus globulus), para adições diferentes de polissulfeto. Esse aumento no desempenho pode ser explicado pelo maior teor de hemicelulose, o que confirma a ação protetora do polissulfeto. Os benefícios da aplicação em plantas de Constituição estes resultados indicam que a adição de polissulfeto de 1,5% teria um lucro anual de 3,8 milhão dólares, no montante de 10.500 mil dólares por ano, com a adição 3% do polissulfeto, razão pela qual se recomenda continuar com um estágio de aplicação industrial dentro da planta, para confirmar o custo final do projeto.
Este estudio tiene por objeto determinar, a través de cocciones Kraft convencionales de laboratorio, los efectos de la adición de polisulfuro en el rendimiento de la pulpa, contenido de hemicelulosas, contenido orgánico del licor negro y propiedades físico-mecánicas de la pulpa; y entregar las recomendaciones para realizar pruebas a nivel industrial en Planta Constitución, la cual posee un proceso RDH. Los resultados muestran aumentos en el rendimiento, con respecto a la referencia, de 3.2 % y 8.5 % en Pinus radiata y de 1.3 % y 3.4 % en Eucalyptus (mezcla de 70 % Eucalyptus nitens y 30 % Eucalyptus globulus), para distintas adiciones de polisulfuro. Este aumento en el rendimiento se puede explicar por el mayor contenido de hemicelulosas, lo que confirma la acción protectora del polisulfuro. Los beneficios de la aplicación en Planta Constitución de estos resultados, indican que para la adición de 1.5 % de polisulfuro se tendría un beneficio anual del orden de US$ 3.800.000; el que ascendería a US$ 10.500.000 al año con la adición de 3 % de polisulfuro, razón por la cual se recomienda continuar con una etapa de aplicación industrial en esa planta, para confirmar la rentabilidad final del proyecto.
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Wilken, Febé Elizabeth. "Establishment of a compatible pathosystem between Eucalyptus nitens and Phytophthora cinnamomi to determine host transcriptional responses." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/79209.
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Candy, Steven Gregory. "Predictive models for integrated pest management of the leaf beetle Chrysophtharta bimaculata in Eucalyptus nitens plantations in Tasmania." Connect to this title online, 1999. http://eprints.utas.edu.au/archive/00000224/.
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Valente, Carlos Manuel Ferreira. "Biological control of Gonipterus platensis: current status and new possibilities." Doctoral thesis, ISA/UL, 2018. http://hdl.handle.net/10400.5/17514.
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Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de AgronomiaThe Australian weevil Gonipterus platensis (Marelli) (Coleoptera: Curculionidae), commonly known as the Eucalyptus snout-beetle, is one of the main pests of eucalypts. Because this is a non-native species, classical biological control with natural enemies from its region of origin should be a viable control strategy. The introduction of the Australian parasitoid Anaphes nitens (Girault) (Hymenoptera: Mymaridae) has been the main method to control the pest worldwide. However, this natural enemy is not completely effective in reducing G. platensis populations and does not avoid the occurrence of damage in several regions. Therefore, it is important to identify effective control alternatives for these areas. In this work, the economic impact of the pest and the benefit of biological control with A. nitens over the last 20 years were assessed, using Portugal as a case study. The results of the economic analysis showed that, without biological control, the losses caused by G. platensis would be at least four times higher than those occurring with partial control by A. nitens. Given the insufficient efficacy of A. nitens, the existence of other natural enemies in Australia that could be used in a classical biological control programme was evaluated. From a set of eight natural enemies identified in Tasmania, the egg parasitoid Anaphes inexpectatus Huber and Prinsloo (Hymenoptera: Mymaridae) was selected for further studies. Laboratory studies comparing the biology of A. inexpectatus and A. nitens at different temperatures, a competition study between these two species, and a risk analysis for the introduction of A. inexpectatus in the Iberian Peninsula were carried out. Overall results suggest that A. inexpectatus might complement parasitism by A. nitens under field conditions without non-target effects on native fauna
N/A
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Satchell, Stuart Dean. "Evaluating profitability of solid timber production from 15 year old pruned and thinned Eucalyptus nitens (Deane & Maiden) in Canterbury." Thesis, University of Canterbury. School of Forestry, 2015. http://hdl.handle.net/10092/10821.
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This case study investigated profitability of a small stand of fast-grown Eucalyptus nitens in Canterbury for sawn timber production. This stand was pruned and thinned and then harvested at 15 years old. An estimate of per-hectare log yields and diameters was made from the stand. Sample logs were sawn, dried and profiled, then products quantified. Log prices were estimated using the residual value method. Prices were summed for sawn products from each log, from which processing expenses and sawmill profit were deducted for an estimate of log value. In the absence of market prices for sawn E. nitens products empirical estimates of price were derived from market survey data. Predictive models were produced from estimated stand log yields along with predicted product revenues and processing costs from sample logs. These were used for estimating per-hectare log residual values from the case study stand trees. Financial returns to the grower were then calculated as discounted cash flows from the estimated log residual values per hectare, taking into account grower costs along with harvesting and transport costs. Best-practice processing methods were identified from the literature and applied as a productivity benchmark. Methods were developed with the view to standardising data across research efforts that seek to improve grade recoveries for E. nitens. A range of factors were investigated that potentially influenced E. nitens log residual value in this case study, including log diameter and log position. Outcomes included a reasonably favourable return on investment for the grower. However, this depended on a number of factors such as land price, distance from processor, product prices, grading methods, drying methods and level of sawmill profit. The application of contemporary best practice small-scale processing methods indicates that E. nitens has potential as a profitable plantation species for solid timber production.
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Fernández, Gutiérrez Marcelo Andrés. "Efecto del tratamiento de inmersión en agua caliente en la permeabilidad de la madera de Eucalyptus nitens (Deane & Maiden) Maiden." Tesis, Universidad de Chile, 2011. http://repositorio.uchile.cl/handle/2250/151552.
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Memoria para optar al Título Profesional de Ingeniero de la MaderaEl presente estudio, realizado en el Departamento de Ingeniería en Maderas y sus Biomateriales, Facultad de Ciencias Forestales y de la Conservación de la Naturaleza, Universidad de Chile, tiene como principal objetivo determinar los coeficientes de permeabilidad gaseosa en madera de Eucalyptus nitens (Deane &. Maiden) Maiden, secada artificialmente con y sin tratamiento previo de inmersión en agua caliente. Las variables consideradas son: tipo de corte, temperatura y tiempo de inmersión. Esta investigación se fundamenta en la necesidad de mejorar los resultados obtenidos en el secado de la madera de esta especie, la que, a pesar de presentar una de las mayores tasas de crecimiento en Chile y significar una gran oportunidad de obtención de madera como tal, su uso comercial se centra en la producción de celulosa y astillas, a causa de los severos defectos originados en dicho proceso. Debido a que la permeabilidad es uno de los factores determinantes del secado, y a que entre mayor sea ésta, teóricamente, mejores son los resultados, se cree que la inmersión en agua caliente, la cual se estaría postulando como posible solución, aumentaría los valores de esta variable.
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Forrester, David Ian, and davidif@unimelb edu au. "Mixed-species plantations of nitrogen-fixing and non-nitrogen-fixing trees." The Australian National University. Faculty of Science, 2005. http://thesis.anu.edu.au./public/adt-ANU20050202.164252.
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Mixed-species plantations of eucalypts and acacias have the potential to improve stand productivity over that of respective monocultures through the facilitative effect of nitrogen-fixation by acacias, and increased resource capture through above- and belowground stratification. However, growth in mixed-species plantations may not be improved compared to that of monocultures when competitive interactions outweigh the effects of improved nutrient availability and resource capture. Careful selection of sites and species is therefore critical to successfully improving stand productivity using mixed-species plantations. This study set out to examine some of the processes and interactions that occur in mixed-species plantations, and the effect nutrient and water availability can have on the growth of mixtures.
In three out of four mixed-species field trials examined in this study, growth was not increased in mixtures compared to monocultures. However, in the fourth field trial, heights, diameters, stand volume and aboveground biomass were higher in mixtures of E. globulus and A. mearnsii from 3-4 years after planting.
The range in outcomes from mixing species in these four trials shows that a fundamental understanding of the underlying processes is required to enable a greater predictive capacity for the circumstances under which mixtures will be successful. Therefore the growth dynamics, processes and interactions were examined in the mixtures of E. globulus and A. mearnsii. The difference in productivity between mixtures and monocultures in this trial increased with time up to age 11 years, when 1:1 mixtures contained twice the aboveground biomass of E. globulus monocultures. The positive growth response of trees in mixture compared to monocultures was the result of accelerated rates of nutrient cycling, a shift in C allocation and reductions in light competition through canopy stratification.
Nitrogen contents of foliage and soil clearly showed that A. mearnsii influenced the N dynamics in this trial. If these changes in N contents were due to N fixation by A. mearnsii, then about 51 and 86 kg N ha-1 yr-1 was fixed in the 1:1 mixtures and A. mearnsii monocultures, respectively. Nitrogen fixation was also examined using the natural abundance method. The delta15N values of foliage collected at 10 years were grouped according to the mycorrhizal status of the host plant. Therefore the discrimination of 15N during transfer from mycorrhizae to the host plant appeared to vary with mycorrhizal status, and the natural abundance of 15N was not used to quantify N fixation.
Rates of N and P cycling in litterfall were significantly higher in stands containing at least 25% A. mearnsii (more than 31 kg N ha-1 yr-1 and more than 0.68 kg P ha-1 yr-1) compared to E. globulus monocultures (24 kg N ha-1 yr-1 and 0.45 kg P ha-1 yr-1). Rates of litter decomposition and N and P release were about twice as high in 1:1 mixtures compared to E. globulus monocultures and were even higher in A. mearnsii monocultures. It is therefore important to select N-fixing species that are capable of cycling nutrients quickly between the plant and soil, and that have readily decomposable litter.
The total belowground C allocation was not significantly different between mixtures and monocultures (14 to 16 Mg C ha-1 yr-1). However, since aboveground net primary production was greater in 1:1 mixtures, the changes in nutrient availability appears to have increased total productivity (both above- and belowground), and reduced the proportion of C allocated belowground in mixtures compared to E. globulus monocultures.
In a pot trial containing mixtures of E. globulus and A. mearnsii both species grew larger in mixture than in monoculture at low N levels, and mixtures were more productive than monocultures. However, at high N levels, E. globulus suppressed A. mearnsii and mixtures were less productive than E. globulus monocultures. Similar effects were found for high and low levels of P.
Therefore resource availability can have a strong influence on the interactions and growth of mixtures. The productivity of mixtures may only be increased on sites where the resource for which competition is reduced in mixture is a major limiting growth resource. For example, if N is not a limiting growth factor then an increase in N availability from N-fixation may not increase growth, and the N-fixing species may compete for other resources such as soil P, moisture or light.
This study has shown that mixtures containing a N-fixing trees and a non-N-fixing trees can be more productive than monocultures, but that this increase in productivity will only occur on certain sites. Examination of the growth, interactions and processes that occurred in mixtures in this study provide useful information that can aid the selection of species combinations and sites.
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Naylor, Sarah. "The Impacts of Species, Physiological Age and Spacing on Tree Form and Branching." Thesis, University of Canterbury. School of Forestry, 2013. http://hdl.handle.net/10092/9898.
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This dissertation examined the impact of species, physiological age and spacing on tree form and branching at a Nelder experiment located near Rolleston, Canterbury. Two species were compared, Pinus radiata and Eucalyptus nitens, at a range of stockings from 271 stems/ha to 40,466 stems/ha. Within the P. radiata, two different physiological ages were compared.
Stocking and species significantly affected (p-value <0.05) tree height, diameter at breast height (DBH), crown depth, branch mortality, branch angle, branch size and internode length. Only stocking was statistically significant for crown width, and height from the ground was also statistically significant for branch angle and branch mortality.
DBH, crown width, crown depth, branch size and branch survival decreased with increasing stocking for both species. Branch angle and average internode length increased as stocking increased for both species, and branch angle and average internode length also increased as you moved away from the base of the tree. DBH, average internode length and branch size were significantly larger for P. radiata across all stockings, however branch mortality and branch angle were significantly larger for E. nitens.
Physiological age was not statistically significant for any aspects of tree form or branching examined in this study.
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Wentzel, Maximilian [Verfasser], Holger [Akademischer Betreuer] Militz, Christian [Gutachter] Brischke, Carsten [Gutachter] Mai, Andrea [Gutachter] Polle, Christian [Gutachter] Ammer, and František [Gutachter] Hapla. "Process optimization of thermal modification of Chilean Eucalyptus nitens plantation wood / Maximilian Wentzel ; Gutachter: Christian Brischke, Carsten Mai, Andrea Polle, Christian Ammer, František Hapla ; Betreuer: Holger Militz." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://d-nb.info/1179449177/34.
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Wentzel, Maximilian Verfasser], Holger [Akademischer Betreuer] [Militz, Christian [Gutachter] Brischke, Carsten [Gutachter] Mai, Andrea Gutachter] Polle, Christian [Gutachter] [Ammer, and František [Gutachter] Hapla. "Process optimization of thermal modification of Chilean Eucalyptus nitens plantation wood / Maximilian Wentzel ; Gutachter: Christian Brischke, Carsten Mai, Andrea Polle, Christian Ammer, František Hapla ; Betreuer: Holger Militz." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://nbn-resolving.de/urn:nbn:de:gbv:7-11858/00-1735-0000-002E-E5A0-2-2.
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Kolokolova, Olga. "Biomass Pyrolysis and Optimisation for Bio-bitumen." Thesis, University of Canterbury. Chemical and Process Engineering, 2013. http://hdl.handle.net/10092/8822.
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Biomass waste has been recognised as a promising, renewable source for future transport fuels.
With 1.7 million hectares of pine plantation forests and 12 million cubic meters of annual residue
produced by sawmills and the pulp and paper industries, New Zealand presents a prime location
where utilisation of these resources can take the next step towards creating a more environmentally
friendly future. In this research, the process of fast pyrolysis was investigated using a laboratoryscale,
nitrogen-blown fluidised bed pyrolyser at CRL Energy. This equipment can process 1–1.5
kg/h of woody biomass in a temperature range of 450–550°C. The purpose of this rig was to determine
the impact of various processing parameters on bio-oil yields. Next, the pyrolysis liquids (bio-oil
and tar) were processed downstream into bio-bitumen. Pyrolysis experiments were carried out
on Pinus Radiata and Eucalyptus Nitens residue sawdust from sawmills and bark feedstock. The
properties of the collected products, including pyrolysis liquids (bio-oil and tar), gas and solid bio-chars,
were measured under different operational conditions. Further analysis was also performed
to determine pH, volatile content, chemical composition and calorific values of the products. The
ultimate goal for this project was to develop a feasible, advanced fast-pyrolysis system for a bio-bitumen
production plant using various biomass feedstocks. Additionally, a design for a bio-bitumen
production plant was developed, and techno-economic analysis was conducted on a number
of plant production yield cases and bio-bitumen manufacture ratios.
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Watson, Liam. "Evaluating the effects of initial stocking, physiological age and species on wood stiffness." Thesis, University of Canterbury. School of Forestry, 2013. http://hdl.handle.net/10092/9901.
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The influence of initial stocking and physiologically aged cuttings (taken from 1-year- old and 5-year-old parents) on corewood modulus of elasticity (MOE) in 6-year-old Pinus radiata D. Don was studied in a Nelder-design experiment in Rolleston, Canterbury. In the same experiment, the influence of initial stocking on MOE in 5-year- old Eucalyptus nitens was also investigated. The study incorporated 19 different stocking levels ranging from 207 to 40,446 stems/ha. Green dynamic modulus of elasticity was assessed in standing trees using the TreeTap stress-wave method over the lower part of the stem (0.3 – 1.9m) for 151 P. radiata trees and 115 E. nitens trees.
The interaction between species and stocking significantly influenced MOE (P<0.001). MOE of P. radiata increased by 55% (or 3.9 GPa) between 271 and 40,466 stems/ha, and by 41% (or 2.2 GPa) between 271 and 4370 stems/ha. MOE of E. nitens was also influenced by stocking but the slope was significantly lower indicating that the effect of stocking was less pronounced than for P. radiata. Over the usual range of stockings for E. nitens there was an insignificant relationship between stocking and stiffness (P=0.335). Trees were also assessed for DBH, height, and stem slenderness (height/ DBH). None of these latter variables had a significant influence on MOE after the effects of stocking and species were accounted for. No effects of physiological age of cuttings were detected in this study.
The findings of this study highlight the importance of stocking as a tool that forest managers can utilize to regulate corewood stiffness in P. radiata trees. These results also suggest that for E. nitens, where wood stiffness is a priority, forest managers could reduce establishment costs by planting at much lower initial stockings. This study also highlights the superior stiffness of E. nitens in direct comparison with P. radiata, with many trees in the experiment already exceeding stiffness thresholds for structural timber in New Zealand.
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Marais, Susann. "Enzymatic hydrolysis with commercial enzymes of a xylan extracted from hardwood pulp." Diss., Pretoria : [s.n], 2008. http://hdl.handle.net/2263/25424.
Full textAbstract:
In the forest products industry the opportunity exists to extract currently under-utilised compounds from the process or waste streams and thereby derive more value from the wood entering the process. A big portion of the hemicellulose content of wood does not form part of the final product. Extracting the hemicelluloses from the waste streams or other locations in the process would allow them to be used more effectively. The predominant hardwood hemicellulose, xylan, is polymeric xylose. Xylose is an important platform sugar in bioconversion strategies and can be converted to fuels and other valuable chemicals. The xylan polymer can be hydrolysed to its xylose monomers by a number of conversion strategies; the most widely known being chemical and enzymatic digestion. Chemical conversion is usually done using acid at elevated temperatures, but high yields are often offset by degradation of the product. On the other hand, enzymatic hydrolysis can be better regulated to prevent unwanted degradation of the monomeric sugar products. Enzymatic hydrolysis has been pronounced the environmentally friendly choice of technology, although it is hampered by low conversions and high cost of enzymes. To date commercial enzymes for biomass conversion are not readily available most of which are still in development. In understanding how to best utilise a xylan, recovered from the pulping process, the potential to convert hardwood xylan to xylose with enzymes currently available on the market was studied. A hardwood xylan extracted from fully bleached Eucalyptus pulp with a chelating agent, Nitren, was used as substrate to evaluate the ability of some commercial enzymes to degrade the extracted xylan to xylose monomers. The enzymes used in this study were not dedicated biomass conversion enzymes, but rather chosen for their xylan degrading potential, i.e. xylanase content. By means of hydrolysis profiles on commercial Birchwood and Oat Spelts xylan as substrates and enzyme characterisation, Multifect xylanase was identified as most promising enzyme for xylan conversion. Multifect contained high levels of xylanase and xylosidase activity in the enzyme preparation. Commercial Birchwood xylan and the extracted Eucalyptus xylan were found to be chemically similar, both composed predominantly of xylose. The hydrolysis profiles obtained on Birchwood xylan could therefore serve as a benchmark against which the hy-drolysis of Eucaluptus xylan could be compared. Full conversion of the Eucalyptus xylan with Multifect could not be achieved, although Multifect completely degraded the Birchwood xylan. The maximum xylose yield that could be obtained on Eucalyptus xylan was 80 % and it was concluded that the remaining 20% was unhydrolysable by the enzyme, most likely due to the limitations in the employed extraction method. It was however noted that up to the point of 80 % conversion higher hydrolysis rates were observed on Eucalyptus xylan than Birchwood xylan with equal charges of Multifect. The differences in hydrolysis rates may have indicated that the Eucalyptus xylan is more accessible to enzyme attack than the Birchwood xylan, likely as a result of the extraction methods used to prepare the xylans. A simple economic evaluation illustrated the weight of various costs in process profitability. The most economic operation of a continuous steady state reactor is at a low enzyme charge, 17 IU/ℓ, and a long retention period, five days, due to the high cost of the enzyme compared to other factors. For a reduced retention time, an investigation into enzyme immobilisation and the use of a packed-bed type reactor is recommended.Dissertation (MEng)--University of Pretoria, 2009.
Chemical Engineering
unrestricted
19
Wilson, Stephen John. "Water stress in transplanted Eucalyptus regnans and Eucalyptus nitens seedlings." Thesis, 1998. https://eprints.utas.edu.au/22020/1/whole_WilsonStephenJohn1999_thesis.pdf.
Full text
20
Stewart, Annie Cecilia. "Bacterial endophytes associated with Eucalyptus nitens clones." Diss., 2012. http://hdl.handle.net/2263/29299.
Full textAbstract:
Plants are colonised by a vast amount of bacteria which are found in parts such as seeds, roots, leaves and fruits while fewer are found on blossoms, stems and vascular tissue. These different parts of plants make up distinct micro ecosystems which may result in different bacterial species (endophytes) colonizing these ecosystems. Such interactions could be for life or only a short period of time and may cause no significant damage or they could be latent pathogens. Isolations of both Gram negative and Gram positive bacteria have been made from an extensive range of plant species and include bacterial genera from the following groups: Firmicutes, Actinobacteria, á Proteobacteria, â Proteobacteria, and ã Proteobacteria. The focus of this study was the endophytic bacterial community of resistant, healthy and diseased Eucalyptus nitens clones, the latter of which showed symptoms of bacterial blight and die back previously described as caused by Pantoea ananatis. The endophytic bacteria of these sampled clones were studied using culturing dependent and independent methods. The focus was on the Enterobacteriaceae in order to determine whether P.ananatis is present as an endophyte of these clones. To obtain the isolates, standard culturing techniques were used, followed by sequence identification of the 16S rRNA as well as two housekeeping genes, rpoB and gyrB. Results obtained from the culturing study were compared to results obtained from a PCR-DGGE study of the same samples. Although no conclusion could be drawn as to which organism present caused the disease symptoms on the susceptible clones, it was seen that Enterobacter and Pantoea, were the most frequently isolated in both of the studies from all clones sampled. This implies that they are present as endophytes in the E.nitens clones, together with Pseudomonas and Bacillus as suggested by the DGGE study. CopyrightDissertation (MSc)--University of Pretoria, 2012.
Microbiology and Plant Pathology
unrestricted
21
Garnett, Trevor Paul. "Ammonium and nitrate uptake by Eucalyptus nitens." Thesis, 1996. https://eprints.utas.edu.au/19940/1/whole_GarnettTrevorPaul1996_thesis.pdf.
Full textAbstract:
Low nitrogen availability commonly limits the growth of Eucalyptus miens
(Deane and Maiden) Maiden plantations in south-eastern Australia. However, until
this study was undertaken little was known of the nitrogen uptake and assimilation
processes of temperate eucalypt species like E. nitens.
In this study ammonium and nitrate uptake by young roots of solution cultured
E. nitens were characterised under a variety of conditions using two different
techniques: net uptake on a macro scale measured as depletion from solution, and net
fluxes on a micro scale estimated from measurements of concentration gradients near
root surfaces using microelectrodes.
Datasets taken from the literature were used to both validate the use of the
depletion method for nitrogen, and to find the most appropriate method to use for the
estimation of kinetic parameters from depletion datasets.
Ammonium and nitrate depletion from solution was characterised with respect
to nitrogen source, pH, temperature, and N status. Ammonium uptake rates were
consistently higher than nitrate uptake rates in all experiments. Uptake rates for both
ammonium and nitrate were higher at pH 4 than at pH 6, and they were reduced to a
similar extent with a decrease in temperature from 20°C to 10°C (Q10 values of 1.3 to
1.9). For ammonium uptake, there was evidence for rapid adaptation of uptake
processes (within 24 hrs) to changing temperature. Nitrogen status, which was
correlated with relative growth rate (RGR), had unclear effects on uptake
characteristics and highlighted deficiencies of measuring uptake by long term (up to
10 hours) nutrient depletion.
Ion selective electrodes were used in the MIFE (microelectrode ion flux
estimation) technique to simultaneously measure ammonium, nitrate, and proton
fluxes within the unstirred layer surrounding roots of E. nitens in solution culture.
Measurements were within the region 20 to 50 mm from the tip of primary roots
approximately 80 mm long. Within this region fluxes of ammonium, nitrate, and
protons varied little, spatially or temporally. Under these conditions there was a
consistent flux stoichiometry for ammonium: nitrate: and protons of 3.1: 1: -6.0.
When ammonium and nitrate concentrations were both set at 100 µM there was no
inhibition of nitrate uptake by ammonium, but at concentrations of ammonium and
nitrate in the range 200-1000 µM there was an apparent suppression of nitrate uptake.
There was evidence for two mechanisms of ammonium uptake. The mechanism at low
concentrations (<200 µM) showed saturation kinetics with a K m of 15 µM whereas at
high concentrations (200-1000µM) an approximately linear increase in uptake
occurred. Excision of the shoot brought about a rapid and dramatic reduction in
fluxes of ammonium, nitrate, and protons.
The apparent preference shown here for ammonium over nitrate could be
indicative of an adaptation by E. nitens to grow in cold, acidic, forest soils where
ammonium is more readily available than nitrate. These results suggest that nitrogen
uptake rates of E. nitens will be maximised if nitrogen is supplied predominantly in the
ammonium form.
22
Williams, DR. "Flowering and seed production in Eucalyptus nitens." Thesis, 2000. https://eprints.utas.edu.au/22047/7/whole_WilliamsDeanRonald2000_thesis_ex_pub_mat.pdf.
Full textAbstract:
This project examined silvicultural and environment factors which affect precocious and
abundant flowering in trees of the economically important plantation species Eucalyptus
nitens with the aim of optimising seed production.
Two separate studies were undertaken to examine how flowering and seed quality were
affected by the macroenvironment. The first studied an altitudinal gradient which would
span the range where operational seed orchards might be located. Flowering abundance
and seed production was greatest on sites where growth rate was highest. Seed weight,
germination success and germination rate decreased as site altitude increased. The second
study examined the effects of water availability. Flowering abundance was highest in
trees experiencing water stress, whilst seed quality remained unaffected by parental water
status. Overall, the maternal tree had a greater influence on seed quality traits than the
environmental effects studied.
On the microenvironmental scale, the effect of tree spacing on flower abundance and
capsule survival was studied at two sites where trees were 5 and 13 years old. As the
spacing between trees increased so too did reproductive yield, not only per tree but also
per hectare. Furthermore, it appears that as trees mature, tree density needs to be
decreased to maintain the maximum reproductive yield per hectare.
To overcome the strong genetic control of flowering precocity a hormone manipulation
approach was tested. The gibberellin biosynthesis inhibitors paclobutrazol, chlormequat
chloride and prohexadione were applied to seedlings and their relative effects compared.
These treatments reduced both growth rate and endogenous levels of GA1 to varying
degrees, with paclobutrazol the most effective. However, none of the treatments
promoted precocious flowering. Further environmental and/or chemical manipulation
would be required to induce precocious flowering in E. nitens seedlings.
The application of nitrogen fertiliser to juvenile trees stimulated precocious and abundant
flowering. This was due in part to accelerated growth rate but nitrogen also acted
independently of growth rate. In contrast, phosphorus had no effect on growth or
reproductive output but did cause trees to undertake vegetative phase change earlier.
Nitrogen fertiliser combined with hormone manipulation with paclobutrazol was applied to
juvenile and mature plantation grown trees to promote precocious and abundant flowering.
There was an additive effect in combining the treatments in promoting both precocious and
abundant flowering.
The production of pedigree seed traditionally required three visits to the mother tree to
carry out controlled pollination. To improve the efficiency of this process, a number of
novel controlled pollination procedures were tested on both E. nitens and E. globulus. A
new single visit pollination protocol for E. globulus was successfully developed, whilst
the techniques applied to E. nitens yielded no advantage over the traditional method. This
new protocol for E. globulus is expected to reduce the cost of pedigreed seed production
by more than half.
This thesis identifies a number of beneficial practices which will improve the productivity
and economic performance of E. nitens seed orchards.
23
Hingston, AB. "Pollination ecology of Eucalyptus globulus subsp. globulus and Eucalyptus nitens (Myrtaceae)." Thesis, 2002. https://eprints.utas.edu.au/17396/1/Hingston-whole-thesis.pdf.
Full textAbstract:
Tasmanian native blue gum Eucalyptus globulus subsp. globulus and its closely
related southeastern Australian mainland congener E. nitens are the major
trees grown in eucalypt plantations in temperate regions of the world.
Plantation stock are mostly grown from seeds, that are increasingly being
collected from seed orchards of trees selected for characters desired by the
forest industry. Seed production and fitness of the resultant trees are
dependent largely upon pollen transfer between flowers on different trees,
because of the partial self-incompatibility in these two species. The
unsuitability of the pollen to transfer by wind necessitates the harnessing of
animals to transfer pollen as they forage at flowers. This research aimed to
determine which animals were effective pollinators of these tree species in
Tasmania.
These two species have contrasting floral forms, associated with enormous
differences in nectar production, that resulted in their flowers being used by
different animals as food sources. The small flowers of E. nitens produced
only 0.3 - 0.6 mg of nectar sugar per day and, accordingly, were visited
exclusively by small, mostly native, insects. Introduced honey bees (Apis
mellifera) and bumble bees (Bombus terrestris), being larger, more energy
demanding insects, were rarely seen visiting flowers of E. nitens, and birds
were never seen attempting to feed from these flowers. In contrast, the large
flowers of E. globulus produced 37- 56 mg of nectar sugar per day, rendering
them attractive to energy demanding birds and exotic bees, as well as the less
energy demanding smaller insects.
Single visits to flowers of E. globulus by swift parrots (Latham us discolor)
resulted in statistically significant increases in seed production above the
levels occurring in unvisited flowers. Although other bird species were not
sufficiently assessed by this method to determine whether they are also
effective pollinators, analyses of their foraging behaviour and pollen loads
suggest they are. In contrast, experiments indicated that insects were poor
pollinators of E. globulus. Single visits to flowers by insects, including honey bees and bumble bees, did not result in statistically significant increases in
seed production above the levels occurring in unvisited flowers. Even
prolonged exposure to insects throughout the life of a flower failed to result
in the production of as many seeds as that following a single swift parrot
visit, despite insects often consuming all of the daily nectar production.
Hence, seed production and the fitness of plantation trees should be
enhanced by management practices that benefit populations of native flowervisiting
insects in seed orchards of E. nitens and birds in orchards of E.
globulus.
24
Eyles, Alieta. "Wound responses of Eucalyptus globulus and E. nitens : anatomy and chemistry." Thesis, 2003. https://eprints.utas.edu.au/19785/1/whole_EylesAlieta2003_thesis.pdf.
Full textAbstract:
The anatomical and chemical host responses of two economically important Eucalyptus
species grown in southern Australia (E globulus and E. nitens) to different wounding
treatments (mechanical, chemical and biological) were investigated. Initially, the project
primarily focused on the role of kino veins as barrier zones in eucalypt tree defence but then
later also included the characterization of the new tissue formed subsequent to wounding, an
area of study previously never been studied in any eucalypt species.
The developmental anatomy and structure of kino veins was examined in three juvenile
Eucalyptus species (E. nitens, E. globulus and E. obliqua) to treatment with an ethylenereleasing
compound, 2-chloroethyl phosphonic acid (CEPA). Unlike E. globulus and
E. obliqua, E. nitens failed to produce kino veins in response to the hormone treatment,
confirming anecdotal evidence that this species does not readily form kino veins. During this
study, histochemical stains including p-dimethylaminocinnamaldehyde (DMACA) and
Coomassie brilliant blue G-250 (BBG-250) were refined to allow the localization of
condensed tannins and hydolyzable tannins, respectively in wood sections. The production of dark extractives (non-structural components of wood and bark) was
regularly observed as part of the wound response in both the phloem and/or xylem tissue and
regardless of the cause of injury. The various wound treatments examined included drill
wounding with fungal inoculations, dry ice wounding, natural infection to stem canker
(Cytonaema sp.) and prune wounding. Analysis of dark extractives extracted from the new
tissue formed after wounding using gas chromatography combined with mass spectrometry
(GC-MS), high performance liquid chromatography (HPLC-UV) coupled to negative ion
electrospray mass spectrometry (ESI-MS) revealed that a complex range of secondary
metabolites was present, including hydrolyzable tannins, proanthocyanidins, flavonone
glycoside, stilbene glycosides, formylated phloroglucinol compounds (FPCs) and volatile
terpenes. These compounds were either undetectable in healthy tissue or else present at significantly lower concentrations than in wound-associated tissue. In particular, the
detection of FPCs in the wound-associated wood was a novel finding, hitherto detected in the
leaves of various eucalypt species. We suggest that the diverse range of secondary
metabolites detected in the wound-associated tissue may have a multi-functional role in
relation to tree wound repair and defence. Crude wound wood extracts were shown to
possess in vitro antimicrobial activity against decay fungi and gram-positive bacteria as well
as in vitro antioxidant activity.
We detail the first reported case of traumatic oil glands induced by wounding in eucalypts.
Histological examinations revealed the new phloem tissue formed in the two years following
green pruning in 5-year-old E. globulus to be largely composed of secretory cavities similar
in appearance to oil glands. Subsequent analysis of extracts by GC-MS confirmed the
presence of volatile terpenes and phenols. The total oil content determined for wound associated
phloem extracts was significantly higher (>50 times) than for healthy stem
phloem extracts.
Based on these chemical and morphological findings, we propose a reassessment of the
importance of wound wood in tree compartmentalization response for E. globulus and
E. nitens, particularly in comparison with other woody tree species.
25
White, D. "Physiological responses to drought of Eucalyptus globulus and Eucalyptus nitens in plantations." Thesis, 1996. https://eprints.utas.edu.au/17453/2/whole-white-thesis.pdf.
Full textAbstract:
Eucalyptus globulus Labill. and E. nitens (Deane and Maiden) Maiden are the predominant hardwood plantation species in southern Australia. This thesis describes some physiological strategies exhibited by these species in response to drought as a means of determining their suitability for establishment on water limited sites. To this end a 2 ha experimental plantation was established on a low rainfall site (ca. 5 1 5 mm a-1) in August 1990. The plantation was divided into irrigated and rainfed blocks so that the effects of soil drought could be separated from those of diurnal and seasonal climatic variation.
Between November 1991 and April 1993 pre-dawn leaf water potential (Ψmax) was significantly lower in the rainfed than the irrigated treatment for six defined periods or stress cycles. At the end of this period, when Ψmax was -2.37 and -2.34 MPa in the rainfed E. globulus and E. nitens respectively, leaf osmotic potential and bulk elastic modulus were still not significantly affected by water stress. At this time a significant interspecific difference was evident in the shape of the desorption isotherms. In the region of positive turgor the mean slope of these relationships was significantly greater in E. nitens (14.5 MPa) than E. globulus (9.3 MPa) resulting in turgor loss at a significantly higher relative water content in E. nitens (0. 86) than E. globulus (0. 79). This interspecific difference in leaf water relations was independent of soil water status.
Allometric relationships between leaf area and sapwood area were developed by destructive sampling in July 1992 and July 1993. These relationships were used with monthly growth data to plot the course of leaf area index (L *) between August 1991 and April 1993. L* was significantly lower in E. nitens than E.globulus throughout the study and was significantly reduced by water stress after November 1992. During the 1992/93 growing season the L* of the rainfed E.globulus increased rapidly after rewatering, resulting in a stepped pattern of leaf area development which was not observed in E. nitens. At the end of the experiment, in April 1993 , L* of the irrigated and rainfed treatments were, respectively, 8.3 and 6.1 in E. globulus and 6.9 and 4.3 in E. nitens.
Daily maximum stomatal conductance of both E. globulus and E. nitens was significantly reduced when Ψmax was <-0 . 5 5 MPa. Reduction in stomatal conductance (gs) as Ψ max decreased was greater in E. nitens than E.globulus. After rewatering, stomatal conductance was slower to recover in E. nitens than E.globulus. These differences caused a significant species by water stress interaction. A phenomenological model of stomatal conductance of upper canopy foliage (gsu) was developed for the irrigated trees. The maximum gsu observed (387 mmol m-2 S-1) was attenuated with normalised functions of total solar radiation (Q), air temperature (T) and vapour pressure deficit (D). This model explained 70% of the variation in gsu. The effect of water stress on the daily total of gsu was accommodated by predicting the ratio of total daily stomatal conductance of rainfed to that of irrigated trees as a function of the cumulative water stress integral for the preceding x days (SΨx), where x was eight days for E. globulus and 20 days for E. nitens. Using SΨx as an independent variable accommodated the longer residual effect of water stress in E. nitens than E. globulus. The model explained 75 and 73% of the residual variation in the daily total of gsu of E. nitens and E. globulus after the direct effects of Q, T and D were removed.
Two estimates of canopy conductance were compared in the irrigated treatment of both species. The first (gc) was a summation of the parallel conductances of three canopy layers and the second (gc') involved integration of the light response function of a leaf level model with respect to cumulative leaf area index. At a daily time step gc' explained 79% of the variation in gc when L* was less than 6, but underestimated gc by as much as 41 % at leaf area indices above 6. This underestimation indicated that at high L*, E. globulus and E. nitens canopies may be weakly coupled to ambient atmospheric conditions. The degree of coupling was investigated in the irrigated E. globulus by simultaneous measurement of transpiration (using sapflow sensors) and stomatal conductance over three days in March 1994. The mean value of the dimensionless decoupling coefficient (Ω) was 0.63. Despite this, a linear relationship with D explained 85% of the variation in transpiration. The vertical profile of Ω and absorbed net radiation were examined and Ω was highest where the lowest amount of radiant energy was absorbed. It is argued that transpiration of irrigated and rainfed E. globulus and nitens may be calculated by treating the canopy as a single layer with a surface conductance of gc'.
E. globulus and nitens responded to drought by stomatal closure rather than by adjustment of the osmotic or elastic properties of their leaves. This response was stronger in E. nitens than E. globulus so that on sites where water stress is moderate and seasonal, E. globulus will probably grow more rapidly than E. nitens. Another major outcome of this thesis is quantification of the different stomatal responses of the two species at the canopy scale in a way that allows transpiration to be calculated from relatively easily obtained variables. Calculation of canopy conductance as gc' predicts a much lower value of gs for foliage at the bottom of high L* canopies than was measured . This suggests that as L* increased the irrigated canopies of both species became more water use efficient. It is argued that if the effects of water stress on gs and L* are considered together then long term water stress will reduce the water use efficiency of E. nitens more than that of E.globulus.
26
Marsh, NR. "Browsing of Eucalyptus nitens seedlings by marsupial herbivores." Thesis, 1998. https://eprints.utas.edu.au/20812/1/whole_MarshNadia1998_thesis.pdf.
Full textAbstract:
Browsing by marsupials on Eucalyptus nitens (Shining gum) was studied in two newly-planted forestry plantations in north west Tasmania, Australia. Sodium monofluoracetate (1080) poison was used at one site (Pearsefield), but not the other (Clipper West). Five seedlots of E. nitens sourced from Southern New South Wales (NSW), Toorongo, Northern NSW, Macalister and Glen Tunnel were planted at each coupe to identify any seedlot preferences by herbivores and to assess differences in levels of damage. Initial heights of the seedlots differed. Three components of seedling damage were analysed: impact of browsing on seedling height, severity of damage and type of damage. Herbivores in the area were recorded in spotlighting surveys.
Five months after planting, 55% of seedlings at Clipper West sustained over 50% damage to their foliage and stem. Glen Tunnel and Macalister seedlings were significantly more damaged than the Southern NSW seedlings. At Pearsefield, only 28% of the seedlings sustained over 50% damage. Glen Tunnel and Toorongo seedlings were significantly more damaged than the other three seedlots at this plantation. At Clipper West, 78% of the damaged seedlings had their apical buds removed, compared with only 50% at Pearsefield.
Five months after planting, mean height of all seedlings was less than at planting due to browsing. Reductions in height were greater at Clipper West than at Pearsefield. In terms of the amount of stem eaten, herbivores preferred the Toorongo and Glen Tunnel seedlots at both plantations. The Southern NSW seedlings were the least preferred.
The Tasmanian pademelon (Thylogale billardierii) was the most frequenfly observed herbivore at Clipper West (7.0/hectare (ha)), compared to 1.2/ha for the Bennett's wallaby (Macropus rufogriseus) and 0.7/ha for the common brushtail possum (Trichosurus vulpecula). Herbivore densities were lower at Pearsefield, and the brushtail possum (0.4/ha) was the most frequently observed. 1080 poison was presumably effective in reducing herbivore numbers, but its effect appeared to be temporary.
Feeding trials, using a captive colony of Tasmanian pademelons, also examined preference and damage to seedlots of the five seedlots E. nitens. Tasmanian pademelons preferred Glen Tunnel seedlings on the basis of the amount of stem eaten, and damaged them more than any other seedlot.
This study suggests that smaller sized seedlings may be more prone to damage, because removal of even a small amount of plant represents a large reduction in a seedling's total biomass. Planting larger seedlings may be a simple means of reducing the impact of herbivores. Management implications of all results are discussed with respect to forestry in Australia.
27
Vega, Rivero MH. "Characterisation of Eucalyptus nitens plantations for veneer production." Thesis, 2016. https://eprints.utas.edu.au/23076/1/Vega_Rivero_whole_thesis_ex_pub_mat.pdf.
Full textAbstract:
Eucalyptus nitens is widely planted in temperate-cold regions around the world,
mainly for pulpwood production. However there is interest in its use for veneerbased
engineered wood products to increase the value and market opportunities
for the E. nitens plantation resource. This study examined such opportunities by
studying factors which affect veneer recovery as well as those which influence
wood properties important for veneer quality.
This thesis had four main experiments. The first experiment examined log-end
splitting with respect to log storage, steaming, plantation site and tree position.
Log-end splitting is a major defect of Eucalyptus logs which has the potential to
significantly reduce the recovery of veneer. Log-end splitting was assessed
immediately post-felling, after transport and storage and immediately prior to
veneer peeling, using upper and lower logs from each of 41 trees from three 20-22
year old plantations. The study found that log-end splitting varied across sites, was
higher in upper than lower logs, and increased with time in storage particularly in
the upper log. In the system studied, log steaming did not significantly affect the
severity of log-end splitting.
The three remaining studies dealt with the assessment of three important wood
properties: density, microfibril angle and modulus of elasticity. SilviScan was the
main approach used for assessing radial and site variation in these characteristics.
However, in the second study an attempt was made to develop more rapid and cost
effective approaches using near-infrared spectroscopy. Radial scans of breast-height
samples from 86 trees and three sites were used to successfully develop nearinfrared
calibrations of these wood properties against 1 mm resolution SilviScan
measurements. However, the capacity of these models to predict wood properties
when applied to independent sites was mixed and generally poor. SilviScan
measurements were therefore used throughout the remainder of the thesis where
comparisons across sites were the main focus.
The third study examined radial change in density, microfibril angle and modulus of
elasticity. While radial change in these veneer-critical wood properties is known to
occur, the extent to which patterns vary, both between sites and trees within sites,
is poorly understood in Eucalyptus. Radial models were developed to determine the
trends in these wood properties from pith to cambium using samples from 2.5 m
above ground level taken from forty-one 20-22 year old trees from three E. nitens
plantations. Simple linear regression models were used to model density, while
non-linear functions were used to model the radial variation of microfibril angle
(asymptotic function) and modulus of elasticity (sigmoidal function), against both
cambial age and percentage area from pith. The radial trends from pith to cambium
in density, microfibril angle and modulus of elasticity found in this study were clear
and matched the general trends in other studies of Eucalyptus. However, significant
differences were obtained in the pattern of radial variation in these wood
properties both among trees within sites as well as between sites. The radial
patterns of change were similar regardless of whether they were assessed based on
cambial age or percentage of the cross-sectional area and site rankings were the
same.
Lastly, the site variation in density, microfibril angle and modulus of elasticity across
the Tasmanian E. nitens plantation estate was modelled. This study was based on
area-weighted tree means obtained from radial SilviScan data. Three trees from
each of 46 sites were used to develop the models and those from an additional 13
sites used as a validation data set. Site-level averages for the three wood
properties were modelled using various forest, environmental and climatic variables
as explanatory variables. Stepwise backward regression was used to select the most
parsimonious linear model for each wood property. The final models included only
plantation age and annual precipitation for all three wood properties as well as
elevation for density. These models were well validated and used to map predicted
spatial variation in these veneer-critical wood properties across the Tasmanian
plantation estate to aid resource characterisation and forest management.
A key result to emerge from this thesis was the importance of site-level factors on
log traits and wood properties likely to impact the quantity and quality of veneer
from Tasmanian E. nitens plantations. This thesis was able to characterise and
predict variation in these wood properties, both within individual trees and across
the Tasmanian plantation estate. These results have direct management
implications, allowing quantification of the impact of different growing conditions
on the wood properties of harvested logs and therefore on the potential veneer
recovery. Coupled with growth and economic models, these results will assist in
optimisation of available forestry resources and future planning.
28
Cheng, Y. "Investigation of mechanical behaviours of Eucalyptus nitens timber." Thesis, 2022. https://eprints.utas.edu.au/47524/1/Cheng_whole_thesis.pdf.
Full textAbstract:
This research focuses on the investigation of the mechanical properties of plantation Eucalyptus nitens timber and the understanding of its underlying failure mechanism above and below the fibre saturation point both experimentally and numerically.
Fast-growing eucalypts are now considered potential building materials; one such re-source is plantation Eucalyptus nitens. To use such a resource as structural or engineered timber, that is to establish design codes and specifications, its compressive and bending strengths need to be studied as they are two important mechanical properties for structural elements in buildings, bridges and decks. For timber members when sub-merged in water or immersed in soil near the river but above the water table, water can be drawn into the wood by capillary action and lead to moisture contents (MC) above fibre saturation point, FSP, which is normally at MC of 25 - 30%. In this study, com-pression and four-point bending experiments were undertaken with a Universal Testing Machine to examine for the first time the anisotropic and/or nonlinear mechanical behaviour of fibre-managed plantation Eucalyptus nitens (E. nitens) samples for low and high MC. Here, low MC means that the MC is less than 15%, which is the normal situation for E. nitens timber as used in the building industry, and high MC means that the MC is above FSP, which is the extreme situation for E. nitens in structural applications when exposed to water.
As the effect of the moisture dependent material properties are very difficult to examine separately using an experimental approach, sophisticated methods, such as finite ele-ment method (FEM) techniques combined with constitutive modelling, are needed to predict ultimate strength more accurately and to assess failure mechanisms in timber under complex loading situations. A newly developed constitutive model extended from an existing constitutive model, namely, a moisture-dependent anisotropic elasto-plasticity model, was proposed in order to display more realistically the short-term de-formation and more accurately the failure mechanisms in E. nitens timber with different moisture contents and varying grain angles. In this model, a criterion which combined the Hill yield criterion with the Drucker–Prager yield criterion was introduced to exam the anisotropic ultimate capacity of wood with consideration of differences in tension and compression. Variation of material properties of E. nitens timber with varying moisture contents is included in a new moisture-dependent anisotropic elasto-plasticity model in order to predict the short-term anisotropic material behaviour of E. nitens timber more accurately when moisture content changes. All these parameters can be derived from experimental data. A UMAT (User-defined mechanical material behaviour in ABAQUS) subroutine within the commercial software ABAQUS was coded to execute the constitutive model for compression, tension and bending. The observed agreement between numerical predictions and experimental investigations shows that the developed constitutive model can be used for E. nitens timber with varying moisture contents. The underlying anisotropic behaviour of E. nitens timber was also examined numerically.
The key findings of this research were that fibre-managed plantation E. nitens timber was highly anisotropic with respect to grain angle and its ductility increased as MC increased. The E. nitens timber with high moisture content exhibited considerably larger deflections at lower maximum loads, while that with low moisture content showed quite abrupt failures at relatively higher ultimate loads. For both tension and compression, stiffness and strength were dependent on moisture content and loading direction, while the failure mode depended mainly on loading direction. That the anisotropy of E. nitens timber was dependent on moisture content sensitivity was proven both numerically and experimentally. The yield surface of E. nitens timber enlarged with a decrease in moisture content, while different failure strengths under tension and compression were found. Compared with moisture content, grain angle had a stronger effect on the anisotropic behaviour of E. nitens timber due to a difference in the stresses state. At a grain angle of 0°, the normal stress along the grain was dominant compared with the corresponding shear stress and the normal stress across the grain. At loading directions of 30°, 45° and 60°, shear stresses played an important role, and for 90°, the effect of normal stress across the grain was significant. Parametric investigation showed that Young’s modulus parallel to the grain and yield stress affected the stiffness and strength significantly when loads were at grain angles between 0° and 15°. Their effects weakened as the grain angle increased from 15° to 45° with almost no effect on compressive strength after 45°. The effect of shear modulus and shear yield stress along wood fibre became the largest contributing factor from 15° to 30°, while after 45° the radial Young’s modulus and yield stress took a dominant role in determining stiffness and strength, respectively, compared with the effects of longitudinal Young’s modulus and shear modulus. The risk of damage to an E. nitens member is expected to increase in high moisture conditions.
The moisture modification factors of Eucalyptus timber at mean level are higher than those of the traditional construction material, Pinus radiata, implying that E. nitens was promising as a material to be used for compressive or bending members in the construction industry, especially in water saturated conditions, for example, in wood piling foundations of buildings near the coast for a long time.
This research will provide basic data for E. nitens in structural applications, and the approaches introduced can be used in future research for assessing the vulnerability of E. nitens members in normal or fully water-saturated states for building and structural applications. The moisture dependent composite plastic constitutive model, by providing results for a comprehensive study of anisotropic plasticity material behaviour incorporating anisotropic and moisture effects, overcame the limitations of the von Mises model and the Hill model with nonlinear isotropic hardening, as they were not always appropriate for E. nitens timber. For example, experiments found that the load deformation behaviour changed from unsteady-state “softening” behaviour at compression parallel to the grain to steady-state “hardening” behaviour at compression perpendicular to the grain. The numerical investigation into the short-term response of E. nitens under compression, tension and bending with high and low moisture contents, compared with the experimental data, demonstrated acceptable agreement, showing that the constitutive model works well for Eucalyptus wood.
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Barton-Johnson, RJ. "Waterlogging in the temperate plantation species Eucalyptus globulus and E. nitens." Thesis, 2006. https://eprints.utas.edu.au/19231/1/whole_Barton-JohnsonRebeccaJane2006_thesis.pdf.
Full textAbstract:
This project investigated the effect of waterlogging on the productivity of
Eucalyptus globulus under field conditions, and the relative tolerance of the two
temperate plantation eucalypt species, E. glob ulus and E. nitens, from the
subgenus Symphyomyrtus, to waterlogging.
In eucalypt plantations across Tasmania, waterlogging is a serious threat to
productivity. It is estimated that at least 11 % of all commercial eucalypt
plantations in Tasmania are affected to some degree, by waterlogging. The losses
incurred by waterlogging during the first 2 years of plantation establishment were
found to have significant long-term effects on tree productivity at two sites across
the state.
In the field, soil indicators of long-term waterlogging, specifically the evidence of
greying, in combination with current seasonal waterlogging and development of
hypoxic soil conditions were found to be the factors closely associated with severe
reductions in tree height and growth. The use of extensive soil mapping and
assessment prior to plantation establishment are therefore effective tools in
identifying potential waterlogging problems.
Under long-term waterlogging, there was no indication of the development of
plant water stress during exposure to waterlogging. Waterlogged seedlings of
both species exhibited reduced foliar nutrient status, with significantly reduced
foliar nitrogen, phosphorus and potassium concentrations. Therefore,
waterlogging-induced nutrient deficiency is a mechanism involved in the growth
reduction of these species under waterlogged conditions.
Various methods of fertiliser application were investigated to determine the most
"effective mode in ameliorating waterlogging damage. Soil-based applications of
slow release fertilisers applied either prior to, or after, a waterlogging event, were
the most successful. Fertiliser application was associated with improved growth,
foliar nutrition and increased aerenchymatous root production.
Reduced availability of nutrients in waterlogged soils and/or reduced uptake of
these nutrients are the two possible mechanisms leading to the development of
foliar nutrient deficiency of waterlogged plants. It was found that under hypoxic
hydroponic culture, seedlings with low nutrient status were capable of an
increased uptake of nutrients when transferred to high nutrient conditions. This
result is significant as it identifies reduced availability of soil nutrients as the
primary mechanism responsible for the development of foliar nutrient deficiency
in E. globulus and E. nitens under waterlogged conditions.
The relationship between aerenchymatous root development and waterlogging
tolerance was investigated. It was determined that singular measurements of root
adaptive capacity should not be used as the sole measure of tolerance to
waterlogging in these species. The regulation of growth and maintenance of
relatively high photosynthetic rates are also useful indicators of tolerance. Using
this array of measures, it was determined that E. nitens was inherently more
waterlogging tolerant than E. globulus. Eucalyptus globulus seedlings
demonstrated a greater potential for increased waterlogging tolerance by the
application of fertiliser regimes.
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Bastos, Margarida Ferreira. "Estudo comparativo da composição química e morfológica das madeiras Eucalyptus globulus e Eucalyptus nitens." Master's thesis, 2018. http://hdl.handle.net/10773/24240.
Full textAbstract:
A madeira de Eucalyptus globulus é a maior fonte de matéria-prima da indústria de pasta e papel dada a sua elevada aptidão papeleira comparativamente a outras espécies. Contudo, a oferta de E. globulus no mercado nacional é deficitária face às necessidades de consumo, pelo que atualmente são incorporadas outras espécies de eucalipto, em particular o E. nitens, para a produção de pasta, afetando as suas propriedades.
O objetivo deste trabalho é avaliar as diferenças de composição química e morfológica de duas madeiras do género Eucalyptus – globulus (Portugal) e nitens (Galiza) – que contribuem para as diferenças relacionadas com o comportamento e desempenho no cozimento kraft.
Os cozimentos kraft das madeiras revelaram a necessidade de uma maior carga de reagentes de cozimento do E. nitens (AA=19,2 % Na2O) em comparação ao E. globulus (AA=15,6 % Na2O) para obter pastas com índice kappa cerca de 16.
A composição química sumária das madeiras foi estudada e a estrutura morfológica foi analisada por microscopia ótica e analisador de fibras. Os componentes macromoleculares das duas madeiras foram isolados seguindo uma metodologia específica para cada um: a lenhina foi isolada por acidólise suave com dioxano e a hemicelulose foi isolada a partir de holocelulose com dimetilsulfóxido (DMSO). As lenhinas foram caracterizadas por análise elementar, RMN de 1H e RMN de 13C, ao passo que as xilanas foram caracterizadas por espectroscopia de RMN de 1H e cromatografia de permeação em gel (GPC).
Ambas as madeiras apresentam uma morfologia semelhante. Ainda assim, a madeira de Eucalyptus nitens possui uma menor densidade devido à maior abundância de vasos e menor espessura das paredes das células. A análise química das madeiras revelou que a madeira de E. nitens possui maior quantidade de lenhina e de compostos extratáveis polifenólicos e menor teor em celulose em relação ao E. globulus.
A partir da comparação da caracterização estrutural das lenhinas concluiu-se que ambas são do tipo S:G (86:14, razão obtida por RMN de 13C). Concluiu-se ainda que a estrutura da lenhina de E. nitens apresenta menor abundância de ligações β-O-4 e maior abundância de carbonos quaternários, revelando uma estrutura mais condensada, o que comparativamente com a lenhina de E. globulus, não favorece a deslenhificação. As xilanas das madeiras apresentam ligeiras diferenças no que se refere à sua estrutura. A xilana de Eucalyptus nitens apresenta um maior grau de substituição com ácidos urónicos e um peso molecular superior.
Em conclusão, o estudo paralelo das madeiras de E. globulus e E. nitens, em particular das características estruturais dos componentes macromoleculares, permitiu justificar o melhor desempenho do E. globulus no processo de produção de pastas celulósicasEucalyptus globulus wood is the largest source of raw material in the pulp and paper industry due to is high potential compared to other species. However, the E. globulus supply in the national market is deficient in relation to the consumption needs, and other Eucalyptus species, in particular E. nitens, are now incorporated into pulp production, affecting its properties. The objective of this work is to evaluate the differences in chemical and morphological composition of two woods of the genus Eucalyptus – globulus (Portugal) and nitens (Galicia) – in order to evaluate their differences in kraft cooking behavior and performance. The kraft cooking of both wood revealed the need for a higher load of cooking reagents for E. nitens (AA=19,2 % Na2O) compared to E. globulus (AA=15,6 % Na2O) to obtain pulps with kappa index about 16. The chemical composition of the woods was studied, and the morphological structure was analyzed by optical microscopy and fiber analyzer. The macromolecular components of the two woods were isolated following specific methodology: the lignin was isolated by mild acidolysis with dioxane and the hemicellulose was isolated from holocellulose with dimethylsulfoxide (DMSO). Lignins were characterized by elemental analysis, 1H NMR and 13C NMR. The xylans were characterized by 1H NMR and gel permeation chromatography (GPC). Both woods have a similar morphology. Nevertheless, the Eucalyptus nitens wood has a lower density due to the greater abundance of vessels and smaller fraction wall thickness. The chemical analysis of the wood showed that the E. nitens wood has a greater amount of lignin and extractable polyphenolic compounds and a lower content of cellulose compared with E. globulus. The comparison of the structural characterization of the lignins allowed to conclude that both are S:G (86:14, ratio obtained by 13C NMR). It was also concluded that the structure of E. nitens lignin has a lower abundance of β-O-4 bonds and a higher abundance of quaternary carbons revealing a more condensed structure, the which compared to E. globulus lignin, does not favor the delignification. Wood xylan present slight differences in their structure. Eucalyptus nitens xylan presents a higher degree of substitution with uronic acids and a higher molecular weight. In conclusion, the parallel study of E. globulus and E. nitens wood, in particular the structural characteristics of the macromolecular components, allowed to justify the better performance of E. globulus in the pulp production process
Mestrado em Química
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Tibbits, WN. "Frost resistance ln Eucalyptus nitens (deane & maiden). maiden." Thesis, 1986. https://eprints.utas.edu.au/17435/1/tibbits-whole-thesis.pdf.
Full textAbstract:
Genetic and physiological aspects of variation in frost resistance were investigated in
Eucalyptus nitens seedlings. Frost resistance was primarily determined by measuring the
relative leakage of electrolytes from leaf discs subjected to artificial frosts, in an air-filled
freezing chamber. The method used was a modification of that developed by other
researchers with eucalypts. Frost resistance assessments made using leaf discs compared
favourably with both artificially frosting whole seedlings and visual assessments of relative
frost damage to field plantings subjected to natural frosts. Transmission electron microscope
observations indicated that frosted leaf discs with a high relative leakage of cellular
electrolytes, had cells that were characterised by rupture of the plasma membrane and
tonoplast, and protoplasm coagulation.
The effects of photoperiod, temperature regime and differential root and shoot
temperatures on frost resistance were examined in both hardening and dehardening E.nitens
seedlings. Both hardening and dehardening processes were markedly influenced by
temperature regime, but no photoperiodic responses were detected. Exposure to
temperatures between 1.5 and 4°C for some part of the day/night cycle resulted in
significantly increased frost resistance. Three separate experiments showed maximum
hardening rates of c. 0.5°C week-1. Increasing the daily amount of low temperature (2 to
3°C), from 8 to 16 h, resulted in increased levels of frost resistance. In contrast, seedlings
exposed to constant 24 h low temperature, were almost 2°C less frost resistant than seedlings
grown with 16 h day-1 low temperature after eight weeks, and suffered considerable water
stress. Whilst heating seedling roots to between 6 and l8°C throughout the constant low air
temperature regime maintained high plant water status, it did not confer any increased frost
resistance. Rates of dehardening in well hardened seedlings increased with increasing day
and/or night temperature in the range 6 to 20°C, but were significantly reduced if roots were
kept at 3°C. The apparent quantitative response of both hardening and dehardening
processes to temperature regime is discussed.
A comprehensive study of the genetic variation for frost resistance in E.nitens was
made by means of artificial frostings, of both whole seedlings and leaf samples, and the
assessment of damage from natural frosts to field trials. Two groups of provenances were
identified. The Western provenance, from the Central Highlands of Victoria, and the
provenance in Northern N.S.W. showed superior hardiness to the Southern N.S.W. and
East Gippsland (Errinundra) provenances. This was demonstrated for plants that were
unhardened, partially hardened and at near maximum hardiness. The critical frost
temperature (50% leaf damage), separating the most and least hardy provenances, increased
with the overall level of hardiness from only 0.3 to over 1.0°C, for unhardened and winter
hardened plants respectively. At well developed levels of hardiness, individual families hardened to below -10C and differed by as much as 2.3 °C. There were also significant
trends of increasing frost resistance with altitude of seed source. The components of
variance in frost resistance for "provenances" were about three times larger than components
for "seedlings-within-provenance", for seedlings subjected to both artificial and natural
frosts.
The early growth and frost resistance of E.nitens was compared with that of 12
other Eucalyptus species in trial plantations on two frost prone sites in Tasmania.
Differences in levels of frost resistance amongst the species were over 7 and 3°C in winter
and summer respectively. Species with the poorest frost resistance in winter, such as
Efraxinoides, E.regnans and E.laevopinea, suffered almost complete mortality at the coldest
site. Only 16 months after planting there were highly significant differences in height and
diameter growth amongst the species, with E.nitens by far the most productive. The
possible interaction between growth rate and relative frost hardiness is discussed. Artificial
frostings of reciprocal grafts between E.nitens and E.gunnii (a species with greater frost
resistance), clearly demonstrated that levels of frost resistance in leaf tissue were largely
determined by foliage genotype, irrespective of root stock genotype.
Intraspecific and interspecific controlled pollinations were attempted on a number of
E.globulus ssp. globulus maternal parents. On the basis of capsule set, data indicate that
E.globulus stigma are receptive a few days after anthesis, reach maximum receptivity after c.
seven days and remain receptive for up to 12 days. Intraspecific and interspecific controlled
pollinations were successfully made using a number of E.nitens maternal parents. Generally
speaking the maternal influence was stronger than the paternal in terms of both number of
seed set and seed weight Controlled breeding methods in E.nitens and E.globulus ssp.
globulus and some implications of the reproductive biology of Eucalyptus species for
breeding programmes are highlighted.
Progeny from crosses onto E.nitens were morphologically intermediate with respect
to both parents. The inheritance of morphological characters in eucalypts is discussed. The
nature of the frost resistance of interspecific hybrids differed amongst the species
combinations, sometimes appearing recessive or dominant but more commonly additive.
E.nitens X E.gunnii seedlings from six different E.nitens mothers (representing the full
range of provenances) all exhibited similar patterns in levels of frost resistance with respect
to their parents. After only four weeks hardening E.nitens X E.gunnii seedlings were on
average l.3°C more frost resistant than their E.nitens mothers but only 0.5°C less frost
resistant than their E.gunnii father. Frost resistance of intraspecific crosses generally
displayed similar patterns (with respect to parents) to those of interspecific crosses.
Factors to consider when selecting and breeding for frost resistance in eucalypts are
discussed.
32
Gendvilas, V. "Thinning and fertiliser effects on Eucalyptus nitens wood properties." Thesis, 2021. https://eprints.utas.edu.au/46043/1/Gendvilas_whole_thesis.pdf.
Full textAbstract:
Eucalyptus nitens is a hardwood plantation species widely planted in cool-temperate regions of the world. Most of the plantations have been established to produce fibre, however, they also have potential to produce more valuable solid-wood products. Silvicultural practices for fibre production are well established, but silviculture for solid-wood production for this species is still being explored. For solid wood production, stiffness and basic density are key wood properties as they determine the suitability of the logs for particular products and ultimately the value of production. Managing eucalypt plantations for the production of solid wood on short rotations requires thinning which is used to produce fewer but larger stems, resulting in a greater yield of sawlogs suitable for processing. To inform processing options available for targeting high-value wood products there is a need to understand how wood properties vary within a tree and how thinning impacts wood quality. Our understanding of how thinning influences the pattern of the within-tree variation of basic density and stiffness is still very limited. Similarly, fertiliser is predominantly used to enhance early growth, but the effect of later applications on tree productivity and fertiliser effect, in addition to thinning, on wood quality traits, are also unknown.
The aim of this thesis was to study the influence of different approaches to silvicultural management on the wood properties of E. nitens plantations grown under regimes developed specifically for the production of solid-wood products. To optimise utilisation of wood as a raw material it is necessary to evaluate wood property variation within the tree as that impacts the value of logs and the cost of final products. Therefore, understanding how silvicultural management influences longitudinal and radial variation in basic density and stiffness is crucial. It is also important to find the most economic, fast and reliable methods of testing wood properties. The data used in this thesis to assess silvicultural impacts was derived from three 19-22 year old E. nitens thinning and fertiliser trials which were pruned and grown in different environmental sites in Tasmania, Australia. These experimental trials were established with the aim of improving existing growth models to better understand the silvicultural and economic implications of commercially relevant pruning, thinning and fertilising operations.
The first experimental chapter of the thesis (Chapter 2) developed methods to improve the prediction of basic density using drilling resistance. Drilling resistance offers a rapid and non-destructive method of estimating basic density, however, to obtain accurate values a correction must be applied. It was not known if the commonly used linear correction provided accurate estimates of basic density or whether an alternative correction was required. To test this correction, 40 discs were drilled radially, then cut into segments which were measured for basic density. In this chapter, the non-linear correction method was developed which allowed a more accurate prediction of basic density across tree stem radius, which is useful for radial basic density assessment. The improved drilling resistance method allows reliable basic density assessments to be conducted on standing trees with minimal costs and labour intensity.
The second experimental chapter of the thesis (Chapter 3) examined the effect of non-commercial and commercial thinning regimes on basic density and stiffness using the non-destructive assessment techniques of drilling resistance and acoustic wave velocity on standing trees across three different sites. Commercial thinning to 300 trees ha\(^{-1}\) led to trees having lower stiffness on all three different sites. However, thinning did not affect basic density. Non-commercial thinning resulted in larger trees and there was no difference in wood properties between non-commercially and commercially thinned trees. Commercial thinning to 500 trees ha\(^{-1}\) had no effect on wood quality. Trees grown at higher elevation on a wetter and colder site had lower basic density and stiffness. The results have confirmed that wood properties are influenced by both silviculture and site environmental differences.
The third experimental study (Chapter 4) examined the effect of commercial thinning on longitudinal and radial variation in wood properties. Stiffness and basic density were measured longitudinally at 2.5 m intervals from the base to 20 m height in the tree and radially at a fixed height of 2.5 m. Longitudinally, wood properties varied more within the tree than they did as a result of thinning. Stiffness was lowest at the bottom of the tree and the highest stiffness was located from 7.5 to 15 m of height. Thinning to 300 trees ha\(^{-1}\) had no effect on stiffness in the bottom of the tree but led to reduced stiffness in upper logs. Similarly, trees in thinned stands had slightly lower basic density, however, longitudinally, basic density increased with tree height. While thinning negatively impacted wood quality traits, this silvicultural treatment results in larger sized trees therefore bigger and more valuable logs can be obtained from the upper sections of the tree where basic density and stiffness is higher. For this reason, the benefits thinning brings to maximising wood growth can outweigh any loss of wood quality. Thinning resulted in significant radial change in wood properties and the thinning effect was apparent soon after the thinning treatment. While thinning results in lower wood quality, it also makes wood properties less variable radially which is better for solid wood processing. Given that wood products require different threshold requirements for size and quality, the information in this study demonstrates how commercial thinning can affect stiffness and basic density and this may significantly influence log allocation and processing strategies.
The previous chapters focused on the effects of one silvicultural treatment (thinning) on wood quality traits. The fourth study (Chapter 5) examined combined fertiliser and thinning silvicultural treatments on growth rates and wood quality on two different sites. One site had fertiliser application before and after thinning while the other site had fertiliser application after thinning only. Tree height and diameter were measured from age 3 to 19 years and non-destructive drilling resistance and acoustic wave velocity were used to assess standing tree wood properties at age 19 years. Basic density and stiffness were not affected by fertiliser addition to the thinning treatment and fertiliser, in addition to thinning, had no effect on radial variation in basic density at 19 years of age. The difference in tree diameters on both sites was observed only due to thinning, resulting in larger trees with lower stiffness. The results suggest that there is no benefit in terms of basic density, stiffness and growth in applying fertiliser in addition to the thinning for timber grown for solid-wood production on longer rotations.
Work presented in this thesis demonstrates significant within-tree variation in basic density and stiffness and that silvicultural management of Eucalyptus nitens plantations is an important tool for manipulation of wood quantity and quality that defines both suitability and value for different solid wood products. The most suitable approach for solid wood production would be to thin early (non-commercially) immediately after pruning to maximise individual tree growth without loss of wood quality. Fertiliser application in combination with commercial thinning is unlikely to result in greater individual tree volume at the end of rotation whereas earlier or non-commercial thinning would be a better option. Thinning results in a relatively small reduction in basic density and stiffness and high variation in basic density and stiffness within the tree suggests that it would be worthwhile segregating logs based on wood quality to maximise solid wood product value.
33
Cardeira, Daniela Pedroso. "Impacto do tratamento fúngico da madeira de eucalipto na branqueabilidade das pastas kraft produzidas." Master's thesis, 2021. http://hdl.handle.net/10316/98238.
Full textAbstract:
Dissertação de Mestrado Integrado em Engenharia Química apresentada à Faculdade de Ciências e TecnologiaO principal objetivo do presente trabalho foi avaliar o impacto do tratamento fúngico das madeiras de 3 espécies de eucalipto, E. globulus, E. urograndis e E. nitens, bem como da mistura de E. globulus com E. urograndis, na branqueabilidade das respetivas pastas kraft cruas. Efetuaram-se pré-tratamentos biológicos, nomeadamente com fungos da podridão branca (WRF - White-rot fungi), tendo-se avaliado 3 fungos, Trametes versicolor (TRA), Ceriporiopsis subvermispora (CES) e Phanerochaete chrysosporium (PHN) com a combinação, ou não, de um tratamento alcalino, antes (pre-ALK) ou após o tratamento fúngico (ALK). Para cada espécie de madeira foi ainda efetuado um ensaio de controlo em que as aparas foram pulverizadas com solução tampão, sem fungo.As pastas kraft estudadas tiveram proveniência dos laboratórios RAIZ, Aveiro, e foram produzidas nas mesmas condições de cozimento (160 ᵒC, durante 1h e com uma carga alcalina de 19 %, base Na2O). As pastas foram posteriormente branqueadas no DEQ/FCTUC, com uma sequência de branqueamento D0EpD1D2, onde se aplicou um fator k (equivalentes de cloro ativo, %, sobre índice kappa) de 0,27 para as pastas de E. globulus e E. nitens e um fator k de 0,31 para as pastas de E. urograndis e de mistura. A carga total de dióxido de cloro prevista através deste fator k, foi distribuída pelos estágios de dióxido de cloro D0, D1 e D2: 65, 25 e 10%, respetivamente. Ao longo do processo de branqueamento foram analisados vários parâmetros como índice kappa, viscosidade, brancura ISO (%) e quantidade de ácidos hexenurónicos. O pré-tratamento das aparas G (100 % E. globulus) com o fungo CES não apresentou resultados promissores quando comparados com as aparas que não sofreram qualquer tipo de tratamento, mas o tratamento com o fungo TRA precedido de um tratamento alcalino, ou apenas este último, permitiu baixar o índice kappa da pasta crua e consequentemente a carga de ClO2 necessária para atingir 90% ISO de brancura. Dos resultados obtidos com a mistura de espécies, E. globulus com E. urograndis pré-tratado (TRA, TRA+ALK ou pré-ALK+TRA), pode-se inferir que, apesar das aparas da espécie mais recalcitrante (E. urograndis) terem sido pré-tratadas, não foram obtidas melhorias tanto no grau de deslenhificação das pastas cruas como no consumo de reagentes de branqueamento, em comparação com o uso de aparas 100 % E. gobulus sem qualquer tipo de tratamento. No entanto, para os restantes conjuntos de aparas individuais pré-tratadas (100 % E. urograndis e 100 % E. nitens) os resultados finais das pastas produzidas foram positivos quando comparados às pastas “controlo”: para E. urograndis o tratamento combinado PHN+ALK permitiu um aumento no grau de deslenhificação e na refletância da pasta crua (variação de 2 unidades no IK e na refletância), uma diminuição de 14% na carga de dióxido de cloro necessária para a pasta branca atingir uma brancura final de 90%, e um aumento de 20% na estabilidade da brancura, sem afetar a viscosidade final; o tratamento combinado pré-ALK+TRA foi o segundo melhor, com efeitos positivos mais modestos; para E. nitens, o tratamento combinado PHN+ALK também permitiu melhorias semelhantes às descritas para E. urongrandis, seguido do tratamento combinado pré-ALK+TRA.
The main objective of the present work was to evaluate the impact of the fungal treatment of wood from 3 species of eucalyptus, E. globulus, E. urograndis and E. nitens, as well as the mixture of E. globulus with E. urograndis, on the bleachability of the respective kraft pulps. Biological pre-treatments with white rot fungi (WRF - White-rot fungi), were considered, namely with Trametes versicolor (TRA), Ceriporiopsis subvermispora (CES) and Phanerochaete chrysosporium (PHN) with or without an alkaline treatment, before (pre-ALK) or after fungal treatment (ALK). Three different eucalypt wood species were used (E. globulus, E. urograndis and E. nitens) as well as the mixture of E. globulus with E. urograndis. For each wood species, a control test was carried out in which the chips were sprayed with a buffer solution, without fungus.The kraft pulps were produced in the laboratories of RAIZ, Aveiro, under the same cooking conditions (160 ᵒC, for 1h and with an alkaline charge of 19 %, as Na2O). The pulps were later bleached at DEQ/FCTUC, using the bleaching sequence D0EpD1D2, where a kappa factor (active Cl2 equivalents, %, divided by the pulp kappa number) of 0,27 was applied for E. globulus and E. nitens pulps and a kappa factor of 0,31 was applied for pulps from E. urograndis and from E. globulus/ E. urograndis mixture. The total chlorine dioxide charge predicted by the kappa factor was split by D0, D1 e D2 stages: 65, 25 e 10%, respectively. During the bleaching process, several parameters were analyzed such as kappa number, viscosity, ISO brightness (%) and the amount of hexenuronic acids.Pre-treatment of G chips (100% E. globulus) with the CES fungus did not show promising results when compared with the chips that did not undergo any type of treatment, but the treatment with the TRA fungus preceded by an alkaline treatment, or only with thes last one, allowed to lower the kappa number of the unbleached pulp and consequently the ClO2 charge necessary to reach 90% ISO brightness.However, for the remaining sets of pre-treated individual chips (100% E. urograndis and 100% E. nitens) the final results of the produced pulps were positive when compared to the “control” pulps: for E. urograndis the combined treatment PHN +ALK allowed an increase in the degree of delignification and in the unbleached pulp reflectance (2 units variation in IK and reflectance), a 14% decrease in the chlorine dioxide charge required for the bleached pulp to reach a final brightness of 90% , and a 20% increase in brightness stability, without affecting the final viscosity; the pre-ALK+TRA combined treatment was the second best, with more modest positive effects; for E. nitens, the PHN+ALK combined treatment also allowed similar improvements to those described for E. urongrandis, followed by the pre-ALK+TRA combined treatment.
34
Barbour, RC. "Gene flow from introduced Eucalyptus plantations into native eucalypt species." Thesis, 2004. https://eprints.utas.edu.au/237/1/01front.pdf.
Full textAbstract:
There has been a massive expansion of Eucalyptus plantations in Australia in the last decade. As most eucalypt species are native to Australia, this has raised concerns about genetic pollution of native species gene pools. To assess the risk of genetic pollution, five key aspects of gene flow from E. nitens plantations in Tasmania were studied. Firstly, the pattern of pollen dispersal from plantations into native E. ovata forests was examined at three sites. The frequency of F1 hybrids among 119 000 progeny, grown from open-pollinated seed collected from E. ovata trees at varying distances from E. nitens plantations, was determined. A leptokurtic pattern of pollen flow was evident, with the mean level of hybridisation at the plantation boundaries (0-100 m) being 14%, dropping to 1% by 200-300 m and continuing at this level to the extent of the studied areas (max. 1600 m). Secondly, the first exotic E. ovata x nitens F1 hybrids actually established in the wild were discovered and verified using morphological and allozyme analyses. Thirdly, field trials were established to assess the fitness of the exotic E. ovata x nitens F1 hybrids in the wild. The hybrids displayed poorer early-age performance relative to their pure E. ovata half-sibs. However, many were still alive and growing successfully two years after planting. Fourthly, surveys of flowering time were conducted on native Symphyomyrtus species, which were potentially at risk of gene flow from plantations. This was combined with a spatial analysis of the proximity of eucalypt plantations to each native species, and used to produce an overall assessment of the potential for exotic hybridisation and gene flow. These results indicated that at least eight of the 16 Symphyomyrtus species in Tasmania appear to have significant potential for pollination by E. nitens, and will need further study. Finally, the crossability of E. nitens pollen on native female Symphyomyrtus species was assessed using artificial pollination techniques. A number of species did not produce hybrids with E. nitens, indicating that post-mating barriers may be acting to prevent hybridisation. Overall results suggest that the main risk of genetic pollution in Tasmania is limited to a few species. Of those species, the ability of first and later generation hybrids to survive to reproductive maturity and backcross with native populations, allowing the introgression of exotic genes, is yet to be assessed.
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Bhuiyan, N. "Identification of genes influencing wood fibre properties in Eucalyptus nitens." 2008. http://repository.unimelb.edu.au/10187/3637.
Full textAbstract:
Eucalypts are a major forest resource globally and the area of eucalypt plantations for pulp and paper production is expanding rapidly in Australia. Consequently, there is an increasing need to breed eucalypts with improved wood properties. Since many high value wood traits are under strong genetic control, identification of DNA markers linked to these traits will have application in breeding programs. In recent years there has been a shift in marker strategy away from QTL mapping in pedigrees to association studies in unrelated populations. In the latter approach, single nucleotide polymorphisms (SNPs) in candidate genes are screened to identify SNPs that significantly associate with wood traits. Significant SNPs could be used for marker-assisted selection (MAS) in breeding programs. The objectives of this study were to identify candidate genes that may influence pulp yield in eucalypts and to identify SNP variants in those genes that associate with superior wood and pulp traits.Approximately 300 trees from a full-sib Eucalyptus nitens progeny derived from a wide intra specific cross were used for gene discovery. DNA microarrays containing ~5800 young xylem of cDNAs Eucalyptus grandis were screened with probes synthesised from RNA isolated from trees with either high or low pulp yield. Forty-six transcripts were differentially regulated, of which 27 were more abundant in high pulp trees and 19 were more abundant in low pulp trees. All differentially expressed cDNAs were partially sequenced and searched against existing gene databases. Six genes were selected as putative pulp yield candidate genes based on their significant similarity to genes with known function and were named EgrCesA3 (cellulose synthase), EgrNAM1 (NAM family protein), EgrXET (xyloglucan endotransglycosylase), EgrGalk (galactokinase), EgrHB1 (class III homeodomain leucine zipper protein) and EgrZnf1 (C3HC4 type zinc finger protein).
Real-Time PCR was carried out on selected genes to confirm the accuracy of the microarray results. Full length cDNAs were obtained for EgrCesA3, EgrHB1 and EgrZnf1 and the candidate genes were partially characterised. An additional candidate gene, the novel gene EgrPAAPA, was selected based on previous research due to its high expression in the cambium and its expression in eucalypt branches. EgrPAAPA was cloned by screening an E. grandis cDNA library and fully sequenced. The full length EgrPAAPA encodes a short 172 amino acid protein rich in alanine, glutamic acid and proline residues. The EgrPAAPA protein appears to be a hydroxyproline-rich glycoprotein (HRGP) and the repetitive ‘PAAPA’ motif suggests that it might play a structural role in cell wall development. Southern blot analysis revealed that E. grandis has a single copy of the EgrPAAPA gene and northern blot analysis revealed that EgrPAAPA is most strongly expressed in xylem tissues.
Allelic variation in EnCesA3, EnNAM1, EnPAAPA and EnHB1 was examined by sequencing each gene in 16 to 24 unrelated E. nitens individuals. SNPs were identified by sequence analysis and patterns of nucleotide diversity, linkage disequilibrium and the selection of suitable polymorphisms were estimated. A moderate level of nucleotide diversity (θw = 0.0056 and π = 0.0039) was observed and linkage disequilibrium was generally low, extending only a few hundred base pairs in each gene. Negative selection has been operating in EnHB1. Selected TagSNPs from EnNAM1, EnHB1 and EnPAAPA were genotyped across 300 unrelated E. nitens trees which had been phenotyped for six wood quality traits including pulp yield, cellulose, lignin, Klason lignin, microfibril angle (MFA) and density. Five highly significant genetic associations (p<0.01) were detected between several SNPs in EnHB1 and all wood quality traits except density. A significant association was also found between EnPAAPA and MFA (p<0.05). No significant associations were found with any of the EnNAM1 SNPs. The strong genetic associations between SNPs in EnHB1 and a range of wood traits is consistent with this gene’s known role as a transcription factor controlling vascular development. Validation of these associations in different populations will be necessary in order to confirm these results. Alternatively, QTL mapping can be performed in order to confirm whether QTL for wood property traits can be detected at the EnHB1 and EnPAAPA loci.
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Murugan, Nelisha. "The performance and rooting of eucalyptus grandis x nitens cuttings." Thesis, 2007. http://hdl.handle.net/10413/490.
Full textAbstract:
Hybrid clones of Eucalyptus grandis and E. nitens (GN) have consistently been shown
to be suitable for planting in cold, dry, marginal plantation sites, where they exhibit high
yields and superior pulp properties. However, their clonal propagation is hindered by
the very poor rooting success of cuttings. The present study aimed at assessing the
effect of cutting type, time of year of setting cuttings and Seradix 2 application on
rooting and development of cuttings of a commercially important Eucalyptus grandis x
Eucalyptus nitens clone (GN107).
Cuttings were prepared from clonal hedge coppice at the Mondi Business Paper, Trahar
Technology Centre, Hilton. Three cutting types were used (cut at different distances
from the node) for each terminal (situated below the apical bud) and non-terminal
cuttings. The leaves were trimmed and, for half the cuttings, the base of the stem of
cuttings were dipped in Seradix 2 rooting powder (3 g kg-1 4-(indole-3-yl)-butyric acid
(IBA). They were then placed into rooting trays (128 inserts/ tray arranged as 8 rows x
16 columns). Seradix 2-treated and Seradix 2-untreated terminal and non-terminal
cuttings, cut at, above and below the node (twelve treatments in total) were set in trays
with one treatment per column of eight replicates, per tray. There were nineteen trays
overall. The trays were filled with peat, perlite and vermiculite (3:3:1) and were
maintained in a Mondi greenhouse, with air temperature at 25°C to 27°C
(thermostatically activated fans), root zone temperature at 28°C (bed heaters) and 20
second misting at 10 minute intervals (automatic misters). The study was carried out in
November 2005, April 2006 and June 2006. In the first experiment, both terminal and
non-terminal cuttings were used; thereafter only non-terminal cuttings were used.
The plantlet yield was very low, regardless of cutting type, Seradix 2 treatment and the
time of year the cuttings were set. The highest plantlet production (12.5%) and rooting
frequencies (13.8%) were achieved with non-terminal cuttings treated with Seradix 2.
Although not statistically significant, Seradix 2 inhibited shoot production (31.4% for
Seradix 2-untreated and 24.2% for treated cuttings). The position at which inserts were
cut in relation to the node did not significantly affect the number of plantlets produced and non-terminal cuttings appeared hardier and performed better than terminal cuttings.
The time of year of setting cuttings did not have any significant effect on plantlet yield,
nonetheless, plantlet yield was highest in cuttings set in November (9.2%) and lowest in
April (0.4%). In addition, cuttings set in November (spring), had superior shoot
development in terms of the number of cuttings that produced shoots (regardless of root
production), shoot length and the mass of shoots relative to root mass. The highest
percentages of cuttings that produced roots (regardless of shoot growth) (10%) and the
highest number of roots per cutting (2) were part of the June trial. Therefore, cuttings
set in June (winter) had superior root development as compared with cuttings set in
November (spring) or April (autumn).
In all of the studies, three rooting patterns were observed in cuttings: roots produced
only from the cut area only (type 1), only from the sides of the stem (type 2) and from
both sites (type 3). Non-terminal cuttings treated with Seradix 2 showed a higher
incidence of types 2 and 3 rooting patterns than the terminal cuttings. Seradix 2
application increased the prevalence of types 2 and 3 rooting patterns. Although not
statistically different, cuttings dipped 2.5 cm into Seradix 2 produced more types 2 and
3 rooting patterns than cuttings dipped at the abaxial end only. Light microscopy of
stem sections of cuttings indicated that roots appeared to originate from the xylem archs
as well as from the cambium.
The collected data indicate that it is necessary to continue research towards improving
the efficiency of plantlet production of GN107 via cuttings. It appears that cuttings of
this clone may be set throughout the year and that terminal cuttings should be avoided.
In addition, the present practice at the Mondi Hilton nursery of treating cuttings with
Seradix 2 needs to be reconsidered as although it increases rooting, it does not increase
plantlet production due to its apparent inhibitory effect on shoot development.Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2007.
37
Blackburn, DP. "Improving Eucalyptus nitens for sawn-board, veneer and paper products." Thesis, 2012. https://eprints.utas.edu.au/12934/10/Blackburn_whole_thesis_ex_pub_mat.pdf.
Full textAbstract:
Eucalyptus nitens is widely planted for pulpwood, and increasingly also for
solid-wood timber products, in cool-temperate climates. This thesis
investigated the potential of tree breeding to improve the properties of
E. nitens grown for sawn boards, pulpwood and veneer products.
Two studies were undertaken using a 14 -15 year old E. nitens provenanceprogeny
trial established in Tasmania and comprising 420 open-pollinated
families collected from three native races. In the first study, methods were
developed to track the identities of 560 pedigreed trees through harvesting,
transportation and sawmill processing. A second study tracked 548 trees
from the same trial through a rotary peeled veneer production system.
Genetic parameters were estimated for a total of 20 tree, log and wood traits
relevant to sawn board, veneer and pulpwood products.
Genetic differences among races of E. nitens were significant in wood
stiffness, growth, stem form and pulpwood traits, but not significant for log
end-splitting and sawn board checking traits. The Southern race had the
most favourable mean values. Significant additive genetic variation within
races was observed in all traits except log-taper, demonstrating that the
quality of plantation-grown E. nitens wood products could be improved
through breeding.
Strongly positive genetic correlations among diameter at breast height (DBH)
at ages 4, 9 and 14 years and between DBH all ages and the traits survival,
log volume and stem straightness, demonstrated that early-age selection for
DBH would not compromise stem straightness and would improve product
volume recovery. Log end-splitting was under moderate genetic control but
there was a negative genetic correlation between end-splitting and solidwood
product volume.Sawn board and veneer sheet stiffness was highly heritable, and strongly
correlated with acoustic wave velocity (AWV), measured in standing trees
and logs. Consistent with previous studies in E. nitens, wood basic density,
near infra red-(NIR) predicted kraft pulp yield (KPY) and cellulose content
(CC) had moderate-to-high heritabilities, although coefficients of additive
genetic variation for these traits were small.
Estimated genetic correlations between standing tree AWV and each of the
traits veneer sheet modulus of elasticity (MOE), sawn-board MOE, KPY, CC
and basic density were highly significant and strongly positive, suggesting
that standing tree AWV could be adopted as an indirect non-destructive
selection criterion for improving solid-wood product stiffness, while
simultaneously improving wood chemical traits favoured by the pulpwood
industry. Basic density had no significant genetic relationship with KPY and
CC, although other studies have reported moderate to strong significant
values.
Surface and internal checking in sawn boards, which are important defects
leading to value downgrade, were shown to be under moderate levels of
additive genetic control. Internal checking in wedges cut from log disks and in
wafer sections cross-cut from processed boards were strongly and positively
genetically correlated. However, the genetic correlation of checking traits with
density and AWV were generally not significant.
Work presented in this thesis clearly demonstrates the potential for genetic
improvement of E. nitens for pulpwood, sawn-boards and veneer production.
A new method of tracking trees in processing studies has been established.
Methods for assessing checking have been developed, and the utility of nondestructive
AWV and NIR techniques has been confirmed for use in E. nitens
breeding programs, aiming to simultaneously improve the quality and
recovered volume of pulpwood and solid-wood products.
38
Medhurst, JL. "Growth and physiology of Eucalyptus nitens in plantations following thinning." Thesis, 2000. https://eprints.utas.edu.au/17417/1/whole-medhurst-thesis.pdf.
Full textAbstract:
In Australia, a new activity is the management of eucalypt plantations for solid
wood products. Thinning is one option for improving log sizes without the need
for long rotation periods. The timing and intensity of thinning operations has a
large bearing on the final products. This thesis describes a series of experiments in
which the growth and physiological responses to thinning in Eucalyptus nitens
(Deane and Maiden) Maiden plantations were identified. The thinning treatments,
in three plantations, included an unthinned control and a range of final stockings
from 600 to 100 trees per hectare.
Diameter growth was significantly improved by thinning. In general, the more
trees removed by thinning, the higher the growth response by the retained trees.
Dominant and co-dominant trees showed the greatest growth response to thinning.
Plantations of low to medium productivity will benefit from early-age thinning.
Based on stand and individual tree responses, a final density of 200 to 300 trees
per hectare may be ideal.
The hydraulic conductivity of sapwood increased with stem height and the ratio of
leaf area to stem sapwood area increased with stem size. Thinning did not alter
these relationships. A broader study across a wide range of E. nitens plantations
found strong relationships between stem sapwood area and tree leaf area that were
independent of site, age and silvicultural treatment.
Crown structure and the development of stand leaf area index following thinning
were investigated. Larger branches were found in the lower crown of thinned trees
and the increase in leaf area as a result of thinning occurred on the northern aspect
of the crown. For trees in unthinned stands, the vertical distribution of leaf area was skewed towards the top of the crown and was correlated with live crown
ratio. The vertical leaf area distribution of trees in a thinned stand was less skewed
and was unrelated to tree size or dominance. Leaf area index, as estimated from
light interception measurements, increased at a constant rate soon after thinning
regardless of residual stand density. In the longer term, residual stand density had
a strong influence on leaf area increase per tree and was correlated with changes
in crown length.
Water use of retained trees increased after thinning through changes in the radial
variation in sap flow across the sapwood. Stand-level water use after thinning was
reasonably predicted from the Penman-Monteith equation scaled by a simple
canopy size factor.
Increases in photosynthetic capacity and changes in foliar nitrogen distribution
occurred after thinning. These responses were well correlated with measured
changes in the light regime and were due primarily to changes in specific leaf
area. Foliar nitrogen content was positively related to light levels throughout the
crowns of trees in thinned and unthinned stands.
Thinning induced both short- and long-term physiological changes. A modelling
analysis demonstrated that increases in crown light interception and light-use
efficiency drive growth response. The relationship of these changes with
environmental factors suggests that, in order to maximise individual tree and stand
productivity, thinning regimes for E. nitens plantations should be designed to
maintain adequate light levels for individual crowns between thinning and
harvest.
39
Kube, Peter Denis. "Genetic improvement of the wood properties of Eucalyptus nitens : breeding to improve solid wood and pulp properties." Thesis, 2005. https://eprints.utas.edu.au/20603/1/whole_KubePeterDenis2005_thesis.pdf.
Full textAbstract:
Eucalyptus nitens is a hardwood plantation species used in cool-temperate regions
of the world. It is mainly used for pulp and paper, although there is increasing
interest in using this species for producing high quality appearance and structural
timber products. Therefore breeding programs need to consider the requirements
of different markets and breed for a variety of end-uses.
The aim of this thesis is to study the genetic control of E. nitens wood properties.
The focus is on three different product groupings which are pulp and paper,
appearance grade timber, and structural grade timber. Pulp and paper traits
studied were wood density, cellulose content, fibre length and fibre coarseness;
appearance grade timber traits were collapse, checking and decay; and structural
grade timber traits were stiffness and microfibril angle.
Genetic parameters and potential genetic gains were estimated using data from 12
year old E. nitens progeny trials grown on three sites. Wood properties were
sampled using 12 mm cores taken at a height of approximately 1 metre.
Relationships between whole tree wood density and core wood density, and whole
tree pulp yield and core cellulose content were investigated. For both traits core
samples were good predictors of whole tree values. Methods were developed to
assess wood collapse and decay using wood cores.
All wood properties except fibre coarseness had significant genetic variation, with
heritabilities ranging from 0.38 to 0.56. The heritability for stem diameter was
0.39. Genetic correlations between traits were mostly significant and reasonably
high. Adverse correlations occurred between diameter and density, diameter and
collapse, diameter and stiffness, and between density and cellulose. Favourable
correlations occurred between diameter and cellulose, density and collapse and
between density and stiffness. Genotype by environment interactions were
sometimes present but were always small.
Genetic selection can significantly improve the quality of wood produced for pulp
and paper, appearance grade timber and structural grade timber. Of particular
importance are the potential gains in collapse (or checking) and stiffness, where
genetic selection can potentially lift the quality grades of appearance and
structural products. Selecting a deployment population for high decay resistance
may minimise the risk of value loss on sites known to have severe decay
problems. Breeding goals for all product groupings are reasonably well correlated
and improved product quality can be achieved in all product groupings without
the need for specialised breeds. Selecting for wood density, as well as growth
rate, is a minimum requirement if high grades of timber are to be produced.
40
Barry, Karen May. "Antimicrobial defence in the sapwood of Eucalyptus nitens : studies of the reaction zone." Thesis, 2001. https://eprints.utas.edu.au/19107/1/whole_BarryKarenMay2001_thesis.pdf.
Full textAbstract:
Decay arising from pruning wounds in plantation-grown Eucalyptus spp. is a concern
for the Australian solid wood products industry, as the potential for decay spread within
the tree is unknown at present. Mechanisms of antimicrobial defence in the xylem of
Eucalyptus nitens were investigated. Key factors investigated within the host-fungal
interaction included phenolics, moisture content, mineral content and anatomical
alterations (tyloses and suberization).
A purple reaction zone was regularly observed at the sapwood interface of decay lesions
developing from naturally-infected pruning wounds in plantation-grown
E. nitens. Total phenols levels were increased substantially and vessel tyloses were
abundant in the reaction zone. A log incubation experiment showed that after 9 months
the reaction zone remained intact while sapwood became decayed. The reaction zone
was significantly drier than healthy sapwood, with lower levels of potassium, and a
lower pH than both sapwood and heartwood. These trends are more similar to conifer
reaction zones than deciduous angiosperms. The mode of reaction zone defence appears
to be a dynamic process (also similar to conifers) rather than a static process typical of
deciduous angiosperms.
The initial stages of antimicrobial defence formation were also studied. Xylem defence
responses occurring in young pot-grown E. nitens saplings were analysed within the
first few weeks following stem wounding and inoculation with the decay fungus
Ganoderma adspersum (which displayed relatively slow colonization of the wounded
xylem). Events occurring most quickly after wounding and inoculation were tylose
formation and phenol accumulation, which indicates that they are key defences. NMR
imaging revealed that changes in xylem moisture content were not rapid after
wounding.
Reaction zone extracts were inhibitory to test-fungi in thin-layer chromatography
bioassays. Analysis of extracts by liquid chromatography — electrospray ionization mass
spectrometry revealed that a diverse range of hydrolyzable tannins were present in E.
nitens wood, including over thirty gallotannins, ellagitannins and phenols. A number of
ellagitannins (particularly pedunculagin) were considerably more abundant in the reaction zone than the healthy sapwood and may contribute to the effectiveness of the
reaction zone as an antimicrobial barrier. The process of reaction zone formation may
be an accentuation of processes that occur when heartwood forms. Heartwood extracts
were qualitatively similar to reaction zone extracts but actual increases in ellagitannins
were not as great.
Conditions such as season of wounding and the type of fungi which become established
in wounds, appear to effect the degree of defence response. This was indicated by
phenol levels. More extensive decay lesions were generally associated with more
phenolic production. Sterile inoculations and weakly-aggressive fungi were associated
with no or little reaction zone formation, while aggressive fungi elicited more
discolouration and phenolic accumulation in advance of infection. This suggests that
non-aggressive fungi are less tolerant of the inherent xylem microenvironment and
active defence responses are not "required" or elicited.
Xylem defence responses appear to be relatively successful in E. nitens. This may be
facilitated (at least in part) by a fast and considerable accumulation of phenolic
compounds. Qualitative studies of phenolic compounds may be a useful indicator of
defensive capacity.
41
Luckman, G. "Aspects of the physiological and chemical control of adventitious root formation in Eucalyptus nitens (Deane & Maiden) Maiden." Thesis, 1996. https://eprints.utas.edu.au/20377/1/whole_LuckmanGregAlan1997_thesis.pdf.
Full textAbstract:
Eucalyptus nitens is an important species in plantation forests in Tasmania
and is becoming important in other cool temperate regions of the world.
Reliable initiation of roots in cuttings is needed, to enhance forest productivity
through the establishment of clonal plantations.
Adventitious root initiation is dependent on the re-polarisation of cells to form a
new root meristem. Failure to initiate roots may be due to the inability of the
plant to undergo re-polarisation of cells to form a new meristem. The research
undertaken has been directed at the manipulation of some of the factors that
are implicated in the establishment of cellular polarity in plants. Several new
techniques for enhancing root initiation have been investigated and shown to
promote root formation in cuttings of E. nitens. The principle conclusions of
the research are outlined below.
It was demonstrated that a high proportion of E. nitens seedlings have the
ability to initiate adventitious roots in cuttings collected from very young
seedlings. This ability is lost quickly as the plant ages. The loss of rooting
ability does not appear to be related to any specific changes in the stem
morphology. Histological examination demonstrated that the loss of rooting
ability is not correlated with the formation of structural barriers within the
stem or callus. Root primordium formation appears to occur in regions of
undifferentiated callus in most cuttings but can also occur directly from the
cambium, with little or no intervening callus phase.
Root initiation was found to be sensitive to the timing and method of auxin
applications. It was possible to increase the proportion of cuttings that initiate
roots by delaying the application of auxin until several weeks after the cuttings
were first placed on the mist-bed. Calcium ions are part of the mechanism by
which auxin signals are translated into cellular actions. Attempts to increase
the rate of root initiation in cuttings by altering calcium levels in the
surrounding medium were inconclusive.
Electric potential differences are known to play a role in the establishment of
cellular polarity and in organogenesis from callus. It was demonstrated that
low voltage electric currents could be used to stimulate root initiation in some cuttings. It was hypothesised that cuttings with substantial basal callus would
be most receptive to this treatment, but this was found not to be the case. The
experiments using electric currents were difficult to replicate and were subject
to unexplained variation in results. Further development of the technique is
required to quantify the effects of such currents and to identify the mode of
action.
Stigmasterol and vitamin D were demonstrated to act as auxin synergists in
the promotion of root initiation in cuttings and also to stimulate the growth of
tissue cultures. ATPase extracts were prepared to investigate whether the
action of sterol potentiation of auxin is associated with changes in membrane
bound I-1+-ATPase activity.
The treatment of cuttings with G compounds, as a method of promoting root
initiation, was investigated. G compounds are a group of naturally occurring
chemicals found in some eucalypt species and are known to inhibit and to boost
root initiation in some species. In cuttings of E. nitens, they were found to
have no significant effects on root initiation.
The results obtained are discussed in terms of the role that the treatments
might play in root morphogenesis through the re-polarisation of cells to create a
new axis. The results support the general hypothesis that treatments aimed at
enhancing the development of cellular polarity are useful in stimulating root
initiation in cuttings. Some suggestions are made for future research, to
develop these initial findings into practical treatments for the propagation of
E. nitens.
42
Swain, Tammy-Lyn. "Development of an advanced generation breeding strategy for Eucalyptus Nitens (Deanne and Maiden) Maiden." Thesis, 2013. http://hdl.handle.net/10413/10748.
Full textAbstract:
The objective of this study was to develop and implement an advanced generation breeding
programme at the Institute for Commercial Forestry Research (ICFR) to manage and
integrate the many and disjunct breeding and production populations of Eucalyptus nitens
established by various entities over the past 30 years at multiple sites in South Africa. To
develop such a breeding strategy, a good understanding of the population genetics, and the
underlying assumptions made by tree breeders about the species, was needed.
Eucalyptus nitens is an important forestry species grown for pulp and paper production in the
temperate, summer rainfall regions of South Africa. A tree improvement programme has
been ongoing at the ICFR for three decades. The measurement and statistical analysis of
data from eight F1 trials established during the 1980s and 1990s have enabled
characterisation of the ICFR’s breeding population. Provenance testing showed that the
more northerly New South Wales (Australia) Eucalyptus nitens provenances of Barren
Mountain and Barrington Tops are distinctly better suited to growth in South Africa than the
southern New South Wales provenances and the Victorian provenances, Penny Saddle and
Bendoc. Generally, the species was not badly affected by Coniothyrium canker. High Type B
genetic correlations for all sites pairs, except one comparison, ranged from 0.75 to 0.99 for
diameter at breast height at 76 to 113 months, indicating very little, or no, genotype by
environment interaction for diameter at breast height for the genotypes tested in the F1
generation. Narrow sense heritability estimates ranged from 0.01 to 0.34, indicating that the
species provides a breeding opportunity for improvement of diameter growth. High genetic
correlations of greater than 0.90 between diameter measurements at 52 to 62 months after
establishment and diameter measurements at 94 or 113 months were found, indicating that
selections can be made reliably at five or six years. Diameter measurements at both 60
months and full rotation (94 to 113 months) were highly correlated with the final height
measurements in these trial series (rg > 0.71 and > 0.83, respectively). Predicted genetic
gains for the F2 over the F1 generation were highest in the trials at Goedehoop and Arthur’s
Seat, with predicted increases in diameter at breast height of 3.07 cm (17.1%) and 3.17 cm
(20.7%), respectively, at full rotation.
Genetic improvement in the species has been slower than anticipated due to delayed and
infrequent flowering and seed production. Three genetic gain trials were established, firstly,
to quantify the gains that have been made in the first generation of improvement in the
breeding programme; and secondly, to establish whether a number of seed source and
orchard variables influence the performance of the progeny. These variables were: the
number of flowering trees in the seed orchard, year of seed collection, seed orchard origin
and composition of seed orchard seed bulks. Diameter at breast height and tree height were
measured in the trials at between 87 and 97 months after establishment, and timber volumes
and survival were calculated. Improved seed orchard bulks performed significantly better
(p < 0.01) than unimproved controls in the field trials, and genetic gains ranging from 23.2 to
164.8 m3ha-1 were observed over the unimproved commercial seed. There were significant
differences (p < 0.01) in progeny growth between the levels of flowering, with higher levels of
flowering (R 40 %) producing substantially greater progeny growth than lower flowering levels
(S 20 %). The seed orchard origin had no effect on progeny growth in this trial series. This
suggests that seed collected from any of the four seed orchards tested will produce trees
with significant improvement in growth.
Various scenarios investigating a range of assumptions were developed and used to predict
genetic gain in the F2 populations. These were compared with realised gains achieved in the
genetic gain trials. The family nested within provenance scenarios proved to be closer to
realised gain than the family across provenance predictions. Two scenarios were used for
family nested within provenance: Firstly, actual flowering for family nested within provenance;
and secondly, estimated flowering after a 30% roguing of poor families. For both scenarios, a
coefficient of relationship of 0.33 predicted gains closest to the realised gains. Indications
were that the effects were additive, and that very little or no heterosis had occurred. The
statistical information suggested that outcrossing in the seed orchards was > 80%. This study
provides an objective and quantitative assessment of the underlying assumptions used for
estimating genetic parameters, and predicting gain in this population of Eucalyptus nitens.
At the same time that genetic gain trials were established, F2 trials were planted, using
seedlots collected from F1 seed orchards. Analysis of the two F2 trials showed that realised
gains for diameter at breast height at 87 months were close to the predicted values and
ranged from 1.02 cm to 1.90 cm. Two exceptions were the sites at Helvetia and Babanango,
where gains were under- and over-predicted, respectively. Realised heritability estimates, which are related directly to the realised gain and the actual selection intensities used in the
seed orchards, reflected this trend. Estimation of breeding values allowed for selection of
elite individuals in top families. Both grand-maternal provenance origin and F1 maternal
effects were significant in the F2 trials. A Type B genetic correlation of 0.61 for diameter at
87 months indicated the possible presence of genotype by environment interactions for the
two F2 sites. A low narrow sense heritability estimate of 0.06 for diameter at breast height at
87 months at one F2 site indicated that more emphasis should be placed on family
information rather than individual information at this site. A heritability estimate of 0.17 for
diameter at breast height at 87 months at the second site, however, indicated that further
improvement is possible in this population of Eucalyptus nitens.
Modelling of predicted genetic gain using various breeding strategy scenarios can be a
useful tool in assisting with the decision on which strategy or management plan will deliver
the most genetic gains per unit time. Such modelling, using the parameters established in the
first part of the study, played an important role in developing the advanced generation
breeding strategy for Eucalyptus nitens. In addition, the modelling exercise highlighted
various management options which could be used to increase gains in the existing
production populations or orchards. Indications are that additional roguing of 1) existing
Clonal Seed Orchards based on results of F2 trials (i.e., backward selection); and 2) F1
Breeding Seed Orchards based on stricter provenance selection, will markedly increase the
quality of the seed produced from these orchards within one season. This study also
highlighted the importance of shortening the breeding cycle in Eucalyptus nitens, particularly
in view of the delays caused by reticent flowering and seed production in the species.
The information and understanding gathered from this study led to the development of a
proposal for an advanced generation breeding strategy in Eucalyptus nitens. This proposal
uses parental reconstruction of open-pollinated progeny to secure pedigree information of
forward selections, thus combining the benefits of increased genetic gain with a shortened
breeding cycle. Recommendations on the management and adaption of current production
populations to increase gains have been made, because establishment and management of
improved material in seed orchards to ensure a sustainable supply of improved seed to the
South African forestry industry, is a key objective of the ICFR Eucalyptus nitens breeding
programme.Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
43
Hasan, O. "The effect of paclobutrazol on flowering activity and gibberellin levels in Eucalyptus nitens and Eucalyptus globulus." Thesis, 1993. https://eprints.utas.edu.au/17320/1/whole-Hasan-thesis.pdf.
Full textAbstract:
Experiments prior to this project demonstrated the capacity of the plant growth
retardant paclobutrazol to enhance flowering in commercially important Eucalyptus
nitens and E. globulus trees and produced anecdotal evidence of this material
reducing time to first flowering. Paclobutrazol is known to reduce the levels of
endogenous gibberellins (GAs) in several species and hence it was hypothesized
that the effects of paclobutrazol on flowering in these Eucalyptus species may be
mediated by an effect on GA levels. The lack of previous identification of GAs in
this genus necessitated the development of extraction and purification procedures to
identify and quantify GAs. The compounds identified suggested that the early 13-
hydroxylation pathway was the dominant mechanism for production of GAs, with
GA 1 as the likely biologically active compound. Persistence of a paclobutrazol
induced increase in flowering of grafted E. nitens material was related to the
continued depression of endogenous GA concentrations. Additionally, higher
concentrations of GA1 were found to be correlated with reduced flowering
responses in this reproductively competent material. A lowering of endogenous
GA levels, in combination with a co-requisite of a period of cold has been
associated with the induction of first flowering in newly grafted E. nitens material.
The effects of cold treatment were not mediated by an effect on levels of GA1 or
GA2o·
Soil applied paclobutrazol was shown to travel up stems and accumulate in leaf
tissue. Breakdown in plant tissue was shown to be rapid, with a half-life likely to
be substantially less than 21 d. Soil and foliar application methods were shown to
produce different patterns of metabolism of labelled paclobutrazol, as demonstrated
by HPLC separation of labelled metabolites extracted from growing apices. The
rate of breakdown in the soil was observed to be variable, but slow in comparison
to that within plant tissues and may be the source of the considerable persistence of
effects of paclobutrazol application observed in some field trials.
Application of paclobutrazol to 6 month old E. globulus seedlings resulted in
the production of flower buds at less than 18 months of age despite the retention of
juvenile foliage. One year later, following normal bud development, anthesis and
pollination, capsules were produced, while maintenance of material in a range of growth conditions over the second winter again demonstrated the strong
requirement for cold seen in grafted E. nitens, as well as revealing an apparent
promotion of flowering associated with reduced pot size. The reduction in
generation time achieved using commercial seedlings was ca. 50% (3 years) which
should be of major benefit to tree breeders, given that the long generation time of
eucalypts is a major determinant of the rate at which genetic gains can be made by
conventional tree breeding methods. In reproductively competent seedlings and
grafts, paclobutrazol application was confirmed to increase the average number of
flower buds per seedling. This could be advantageous when seed requirements
from an elite tree are high, or when yearly seed yield tends to be variable.
44
Pelica, João Paulo Ferro. "Fitorremediação em solos contaminados com arsénio, por duas espécies de Eucalyptus (Eucalyptus globulus Labill e Eucalyptus nitens Deane & Maiden)." Doctoral thesis, 2017. http://hdl.handle.net/10362/29480.
Full textAbstract:
Nos últimos anos, com o aumento da população mundial e a sobre-exploração dos recursos naturais (devido à mineração, agricultura e industria), a poluição dos solos (nomeadamente com arsénio) tem gradualmente aumentado. Neste enquadramento, neste estudo, caracterizou-se a deposição e o teor médio do arsénio nas zonas mineiras de Neves-Corvo e de São Domingos, para definição e implementação de um ensaio experimental de fitorremediação no Campus da Faculdade de Ciências e Tecnologia / Universidade Nova de Lisboa. Após transplantação e aclimatação das plantas da Eucalyptus globulus Labill e E. nitens Deane & Maiden, com 11 e 17 meses de idade, respetivamente, entre Janeiro e Julho de 2015, as plantas foram submetidas a 33 e 66 mg de As Kg-1solo. Procedeu-se então a uma caracterização bimensal da cinética de absorção e translocação do arsénio para a parte aérea, aferindo-se ainda os parâmetros de crescimento e as taxas de síntese de fotoassimilados. Face ao aumento da concentração de arsénio no solo, verificou-se o aumento dos respetivos teores nas raízes (até 102,2 e 133,3 μg As g-1peso seco, na E. globulus e E. nitens, respetivamente) e nas folhas (até 11,64 μg As g-1peso seco na E. nitens). Constatou-se ainda que a E. globulus registou uma maior taxa de crescimento, produção de biomassa e maior tolerância ao arsénio. Paralelamente, na E. nitens o tratamento com 200 mg de As apresentou variações significativas, relativamente à parametrização fotossintética, evidenciando-se danos no fotossistema II. Não existindo nenhuma legislação europeia ou nacional que promova, ou impossibilite, a descontaminação de solos por fitorremediação, por ser de interesse público, discute-se, a implementação da E. globulus, como possível solução para a descontaminação de áreas poluídas com arsénio, nomeadamente na mina de Neves-Corvo.
45
Pound, Leanne Marie. "Self-incompatibility in Eucalyptus globulus and E. nitens / Leanne Marie Pound." 2002. http://hdl.handle.net/2440/21941.
Full textAbstract:
"November, 2002"Bibliography: leaves 119-133
x, 135, [123] leaves : plates (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 2003
46
Wentzel, Maximilian. "Process optimization of thermal modification of Chilean Eucalyptus nitens plantation wood." Doctoral thesis, 2019. http://hdl.handle.net/11858/00-1735-0000-002E-E5A0-2.
Full text
47
Volker, PW. "Quantitative genetics of Eucalyptus globulus, E. nitens and their F1 hybrid." Thesis, 2002. https://eprints.utas.edu.au/3586/2/Front_Matter.pdf.
Full textAbstract:
This thesis examines the quantitative genetics of intra- and inter-specific
hybrids of E. globulus ssp. globulus and E. nitens. The trials established to make
this study are unique in forestry, due to the fact that the same parents have
been used in open-pollination, intra- and inter-provenance (or intra-species)
crosses and inter-species F1 hybrids. This has allowed direct comparison of
genetic parameters derived from different cross types. The traits examined
include frost resistance using an electrical conductivity method, growth
(diameter at breast height over bark DBHOB, at ages 2, 3, 4, 6 and 10 years)
and Pilodyn penetration at age 6 years as an indirect measure of wood density.
The results demonstrate that the measured performance of frost, growth and
Pilodyn traits in the inter-specific Fi hybrid E. nitens x globulus is always
intermediate or comparable with one or other of the parent species. In the
frost trait, the inter-specific hybrid was no better than the frost sensitive E.
globulus, so there is no overall advantage in producing the hybrid for this trait.
Negative mid-parent heterosis was observed for early age growth traits in
inter-specific E. nitens x globulus FI hybrids involving Taranna E. globulus male
parents. The inter-specific FI hybrids demonstrated generally poor survival
and a high proportion of abnormal and slow growing phenotypes, which
eventually died. This latter phenomenon was not evident in pure species
crosses, either within or between provenances.
It is shown that in E. globulus open-pollinated progeny estimates of additive
genetic parameters are inflated and that breeding values for growth in E.
globulus are poorly estimated, possibly due to the confounding effects of
variation in inbreeding. This was not the case for traits of high heritability
such as Pilodyn. Within the E. nitens population studied, open-pollinated
estimates compared well with control-pollinated estimates for all traits.
Genetic parameter estimates from control-pollinated progeny indicate low
heritability for growth in E. globulus which diminish over time. Dominance
effects were low and comparable with additive genetic effects but were site
specific. In E. nitens heritability for growth is moderate to high, tending to
increase over time with significantly low levels of dominance, which diminish
over time. Pilodyn has low to moderate heritabilities with low levels of
dominance in both species. Moderate levels of heritability were demonstrated
for frost resistance in both species, but dominance effects could not be
accurately estimated.
The correlation of performance of parents in intia-specific crosses through
their General Combining Ability (GCA) is compared with performance in
inter-specific hybrids through General Hybridising Ability (GHA). It is shown
that there is little or no correlation between GCA and GHA in inter-specific F1
hybrids for growth or frost resistance, but there was a good correlation for
Pilodyn. This indicates that, for growth and frost resistance, there may be
different genes, which contribute to expression between species and these may
not combine according to classical quantitative genetic theory. In contrast,
within E. globulus there was very high correlation of within-provenance GCA
with between-provenance GHA for growth and Pilodyn, indicating the same
genes are acting within the species, regardless of provenance.
It is demonstrated that standard quantitative genetic models do not cope
adequately with inter-specific F1 hybrid populations for growth traits in this
case. In addition, the implication for breeding and deployment of interspecific
Fi hybrids is compromised by the lack of ability to predict
performance of potential hybrid combinations from pure species performance
of parents.
48
Volker, PW. "Quantitative genetics. of Eucalyptus globulus, E. nitens and their F1 'hybrid." 2002. http://eprints.utas.edu.au/3586.
Full textAbstract:
This thesis examines the quantitative genetics of intra- and inter-specific
hybrids of E. globzllus ssp. globl~lus and E. nitens. The trials established to make
this study are unique in forestry, due to the fact that the same parents have
been used in open-pollination, intra- and inter-provenance (or intra-species)
crosses and inter-species F1 hybrids. This has allowed direct comparison of
genetic parameters derived from different cross types. The traits examined
include frost resistance using an electrical conductivity method, growth
(diameter at breast height over bark DBHOB, at ages 2, 3, 4, 6 and 10 years)
and Pilodyn penetration at age 6 years as an indirect measure of wood density.
The results demonstrate that the measured performance of frost, growth and
Pilodyn traits in the inter-specific Fi hybrid E. nitens x globulus is always
intermediate or comparable with one or other of the parent species. In the
frost trait, the inter-specific hybrid was no better than the frost sensitive E.
globulus, so there is no overall advantage in producing the hybrid for this trait.
Negative mid-parent heterosis was observed for early age growth traits in
inter-specific E. nitens x globulus FI hybrids involving Taranna E. globulus male
parents. The inter-specific FI hybrids demonstrated generally poor survival
and a high proportion of abnormal and slow growing phenotypes, which
eventually died. This latter phenomenon was not evident in pure species
crosses, either within or between provenances.
It is shown that in E. globulus open-pollinated progeny estimates of additive
genetic parameters are inflated and that breeding values for growth in E.
globulus are poorly estimated, possibly due to the confounding effects of
variation in inbreeding. This was not the case for traits of high heritability
such as Pilodyn. Within the E. nitens population studied, open-pollinated
estimates compared well with control-pollinated estimates for all traits.
Genetic parameter estimates from control-pollinated progeny indicate low
heritability for growth in E. globulus which diminish over time. Dominance
effects were low and comparable with additive genetic effects but were site
specific. In E. nitens heritability for growth is moderate to high, tending to
increase over time with significantly low levels of dominance, which diminish
over time. Pilodyn has low to moderate heritabilities with low levels of
dominance in both species. Moderate levels of heritability were demonstrated
for frost resistance in both species, but dominance effects could not be
accurately estimated.
The correlation of performance of parents in intia-specific crosses through
their General Combining Ability (GCA) is compared with performance in
inter-specific hybrids through General Hybridising Ability (GHA). It is shown
that there is little or no correlation between GCA and GHA in inter-specific F1
hybrids for growth or frost resistance, but there was a good correlation for
Pilodyn. This indicates that, for growth and frost resistance, there may be
different genes, which contribute to expression between species and these may
not combine according to classical quantitative genetic theory. In contrast,
within E. globulus there was very high correlation of within-provenance GCA
with between-provenance GHA for growth and Pilodyn, indicating the same
genes are acting within the species, regardless of provenance.
It is demonstrated that standard quantitative genetic models do not cope
adequately with inter-specific F1 hybrid populations for growth traits in this
case. In addition, the implication for breeding and deployment of interspecific
Fi hybrids is compromised by the lack of ability to predict
performance of potential hybrid combinations from pure species performance
of parents.
49
Close, Dugald Craig. "Cold-induced photoinhibition, pigment chemistry, growth and nutrition of Eucalyptus nitens and E. globulus seedlings during establishment." Thesis, 2001. https://eprints.utas.edu.au/19109/1/whole_CloseDugaldCraig2001_thesis.pdf.
Full textAbstract:
Australia is aiming to treble plantation wood production by 2020. Eucalyptus
globulus Labill. and E. nitens (Deane and Maidem) Maiden are the predominant
plantation species in southern Australia. This thesis describes physiological strategies
employed by these species in response to cold-induced photoinhibition during
seedling establishment. A series of experiments was conducted on seedlings prehardened
in the nursery. Their physiological and growth responses after planting in
the field was investigated.
A field trial was established at 350 m asl in early spring 1997. Severe cold-induced
photoinhibition caused photodamage which restricted growth of non-hardened E.
globulus. Artificial shading alleviated cold-induced photoinhibition and photodamage
in both E. globulus and E. nitens, and increased growth in E. globulus. Before
planting, nutrient-starved E. nitens were photoinhibited and had high anthocyanin
levels. Increased photoinhibition was not measured after planting because of
sustained xanthophyll activity and/or light attenuation by high anthocyanin levels. In
other treatments changes in anthocyanin levels were related to the severity of coldinduced
photoinhibition. Relative to E. nitens, growth of E. globulus was more affected by cold-induced
photoinhibition and photodamage. This was possibly due to inherently low levels of
carotenoids and lack of acclimation to cold temperatures. The effects of shading on
E. globulus and the absence of any effect of cold-hardening on E. nitens stresses the
importance of incident light and pigment levels in cold-induced photoinhibition. In a second field trial, an early winter planting of E. nitens was established at 700 m
asl in June 1998. Shading may have increased biomass production because of
alleviation of cold-induced photoinhibition. Growth in non-shaded than shaded
seedlings was greater overall due to higher biomass production in spring and summer.
Seedlings grew taller when shaded due to apical dominance. Fertilised seedlings
produced more biomass in the field than non-fertilised seedlings.
Low growth rates of E. nitens during winter at 700 m asl were associated with high
NPQ and sustained xanthophyll activity; photooxidation of chlorophylls, xanthophylls
and 13-carotene (which decreased light absorption), and increases in lutein and
neoxanthin (which indicated an antioxidant role). In general fertilised seedlings had
higher pigment levels which maintained higher levels of light utilisation and
dissipation. A controlled environment experiment which induced cold-induced
photoinhibition, confirmed that galloylglucoses and flavonoids can act as antioxidants
during seedling establishment. Sideroxylonals were also implicated in this role.
Anthocyanin kinetics during seedling establishment indicated absorption of irradiance
between 400 and 590 nm during periods of greatest cold-induced photoinhibition.
Chemical fractionation of leaf N and P indicated that E. globulus is more efficient at
acquiring N and P than E. nitens. After planting, re-translocation of stored foliar
protein N and inorganic P to roots occurred in both species. Greater amounts of retranslocation
in fertilised seedlings may contribute to their superior growth in the
field.
Planting seedlings involves risk. Planting nutrient-starved seedlings may decrease the
risk of severe cold-induced photoinhibiiton and photodamage. However, this is at the
expense of optimal growth performance. Planting altitude and season will determine
whether fertilised or nutrient-starved seedlings should be planted.
50
Ziganira, Matabaro. "Influence of stockplant management on yield and subsequent rooting of cuttings of cold-tolerant Eucalyptus grandis x E. nitens clones." Thesis, 2012. http://hdl.handle.net/10413/8654.
Full textAbstract:
Clones of the Eucalyptus grandis x Eucayptus nitens (GN) hybrids were produced and selected through the CSIR‟s breeding programmes for colder plantation sites in South Africa. Some GN clones consistently exhibit high and superior pulp properties, which makes them valuable for commercial plantations in South Africa. In nurseries, stockplants are usually seven cm in length and maintained at high (100 x1.5 m-2) planting density. However, rooting frequency varies with season and little is known about the impact of position of cuttings on overall rooting frequency of a clone. The aim of this study was to investigate the effect of size and planting density of stockplants in mini-hedges, on the yield and subsequent rooting of cuttings from various positions of GN clones of known rooting potential (i.e. GN 018B: difficult-to-root and PP 2107: easy-to-root clones).
Stockplants (10 cm vs. 20 cm) were established at high (100 x 1.5 m-2) and at low (25 x 1.5 m-2) densities for GN 018B and PP 2107 under commercial nursery conditions in a polyethylene tunnel. Cuttings were harvested every two to three weeks in September-October 2010 (spring), December 2010-January 2011 (summer), April-May 2011 (autumn) and June-July 2011 (winter). The harvested material was 5 – 7 cm in length and the light intensity received by individual stockplants at the two planting density levels was recorded. Harvested cuttings from the three positions (apical, middle and basal shoots) were used for: (i) rooting experiments under nursery conditions, (ii) bio-stimulant analysis using the mung bean bioassay, and (iii) analysis of soluble sugars.
Between spring and summer 2010, the two GN clones established at low density yielded a similar number of cuttings, but differences in the rooting frequencies were significant in favour of PP 2107 clone. Similar observations were made at high density in terms of production of cuttings, but the significant differences in the rooting observations were reversed between the clones. The GN 018B clone had low rooting rates in summer under nursery conditions but its tissue extracts promoted higher rooting in the bioassay during that time, when compared to spring. Spring and summer had similar effects on rooting responses of PP 2107 cuttings in nursery and bioassay experiments. For both clones, short stockplants produced fewer cuttings but had a higher rooting frequency than cuttings from tall stockplants, with a high rooting frequency recorded from basal cuttings. Similar results
were observed in the bioassay experiments which showed high rooting potential of mung bean hypocotyls cuttings using tissue extracts of PP 2107 cuttings maintained at high planting density. Although apical cutting tissues had high concentration of sugars (i.e. sucrose, glucose and fructose), their rooting rates were usually lower at high and low planting density compared to middle and basal cuttings. Sucrose concentration was the highest sugar present in stockplants grown under low planting density. A higher and lower rooting frequency was also observed in autumn although the two clones responded differently to Quambalaria eucalypti (Sporothrix eucalypti) disease infestations. Position, size and genotype had a significant impact on type and concentration of sugar (i.e. sucrose, glucose and fructose), particularly in PP 2107 clone, although rooting rates in the bioassay did not correlate with sugar contents of Eucalyptus cuttings.
High carbohydrate (i.e. soluble sugar) content and auxin concentration increased production and subsequent rooting of cuttings across both clones, particularly in spring. Furthermore, rooting was enhanced by relatively higher light intensity intercepted by individual stockplants and in particular the GN 018B clone. Light intensity in the high and low planting densities caused variation in the rooting frequencies thereby increasing or decreasing soluble sugar and auxin concentrations of the two clones. Light intensity and fertiliser concentration received by tall and short stockplants impacted on endogenous hormone levels thereby increasing or decreasing rooting. High sugar concentration levels of PP 2107 clone increased its susceptibility to fungal infection thereby decreasing its rooting frequency in autumn, as its rooting rates increased in winter.
Overall results of the investigation revealed that PP 2107 clone has higher rooting potential than GN 018B clone, in particular at high planting density and if stockplants are not infected by fungal diseases. Higher sugar levels were recorded in spring for PP 2107, although rooting rates of mung bean hypocotyl cuttings were higher in summer for GN 018B, suggesting that sugars have nothing to do with rooting of GN cuttings. Season, planting density and size of stockplants affect the rooting frequency of GN clone. Thus, short stockplants maintained at low and high planting densities are recommended for GN 018B and PP 2107 respectively, although the impacts of fertilisers and pathogen resistance on rooting rates still need to be investigated under similar conditions.Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.