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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Overcoming biological barriers to control pollinated seed production in Eucalyptus.

Horsley, Tasmien Nadine. January 2009 (has links)
The overall aim of this PhD study was to develop protocols to improve the efficiency of eucalypt controlled pollinations (CPs) in order to make it more cost-effective for forestry companies to perform them on a commercial scale on small-flowered species. To achieve this, three research areas were explored, namely pollen handling, breeding systems and controlled pollination technique. Study species were Eucalyptus grandis, E. dunnii, E. smithii, E. nitens, E. urophylla and E. macarthurii. The first specific aim of the study was to identify a suitable liquid in vitro germination medium for reliably testing pollen viability of all six study species. Six levels of sucrose [0, 10, 20, 30, 40 and 50% (w/v)] were tested, both with (0.15 mg l-1) and without boric acid. The optimal sucrose concentration was found to be 30% (w/v), with boric acid stimulating pollen tube growth. A second aim was to determine temperatures suitable for the short-, medium- and long-term storage of E. smithii, E. nitens and E. grandis pollen. Pollen samples were stored at room (25oC), refrigerator (4oC), freezer (-10oC) and liquid nitrogen (-196oC) temperatures, and pollen viability tested every two months over a 12-month period. There was a rapid decline in the germination of pollen stored at 25oC, while temperatures cooler than 4oC appeared to maintain pollen viability for the duration of the 12-month study. Recommendations were thus to use a refrigerator for short-term (< 2 months), a freezer for medium-term (up to 10 months) and cryopreservation for longer-term storage. In the second part of the study, breeding systems of E. urophylla and E. grandis were examined by studying pollen-tube growth in the style after single-donor self- and cross-pollinations. Results showed that, in addition to both species exhibiting reduced seed yields following self-pollination, pollen tubes from self-pollen took significantly longer than those from cross-pollen to grow to the base of the style. This suggested the presence of both late-acting self-incompatibility and cryptic self-incompatibility (CSI) as possible mechanisms responsible for outcrossing in these two species. In a follow-up study, the siring ability of self- and cross-pollen was examined after single- and mixed-donor pollinations were performed on E. grandis. Once again, single-donor cross-pollinations resulted in a significantly higher number of seeds compared to self-pollinations. In addition, microsatellite molecular markers revealed that 100% of the progeny from mixed (self + outcross) pollinations were outcrossed, confirming the competitive advantage of cross-pollen. To date, CSI has never been associated with Eucalyptus, making this the first study to suggest its presence in the genus. For the final study area, three CP-techniques were compared, namely the Conventional method, One Stop Pollination (OSP) and Artificially Induced Protogyny (AIP), in E. grandis, E. smithii and E. macarthurii maternal parents. Although the AIP technique produced the highest seed yields in all three species, it also resulted in high self- and foreign-pollen contamination (determined using microsatellite markers). This necessitated exploration of different methods of isolating the pollinated flower, and this led to the identification of a novel method which uses sodium alginate gel. Flowers hand-pollinated and isolated with sodium alginate produced progeny that were 100% outcrossed with the applied pollen, confirming the superiority of this innovative isolation technique compared to the currently used exclusion bag. Sodium alginate isolation also increased the efficiency of CPs as the gel was naturally shed, removing the need for operators to return to the tree to remove the isolation material, and thereby reducing the cost per seed. Application of these results should make commercial CP-seed production of small-flowered eucalypts a practical reality. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
2

’The site strikes back’: multi-level forest governance and participation in northern Finland

Sarkki, S. (Simo) 09 December 2011 (has links)
Abstract New forms of environmental governance are implemented with promises associated with more flexible and participatory decision-making. However, resistance towards these ways of doing decisions occurs also in relation to forests in northern Finland. This thesis seeks to explain this resistance and to discuss how participation in the context of multi-level environmental governance can be enhanced. A combination of anthropological fieldwork methods and concepts from environmental politics is used to create a bottom-up research strategy to examine forest governance. Based on theme interviews, planning documents and press releases of various actors, this thesis identifies problems for hybrid forest governance modes, which combine State, market, and civil society actors in decision-making processes. Based on selected topical case studies regarding state-owned commercial forests in Inari, Forest Lapland, Muonio, and Liperinsuo three different governance modes are identified: a State-based mode with a participatory dimension and two ‘pressure’ modes taking place via market-based campaigns of environmental NGOs and local protests. Concerning the protected areas, namely Malla Strict Nature Reserve and the Pallas-Ylläs and Oulanka national parks, one governance mode is identified as taking place on the vertical park managements – international conservation agencies – local resource users axis. A major explanation for resistance towards the different governance modes is that decision-making processes neglect site-specifics. Related problems include missing stakeholders, lack of site-specific discussions in planning processes, generalised concepts used in standardisation practices, engagement of ‘faraway’ stakeholders in decision processes, and lack of transparency. As a result, ‘the site strikes back’ responses, i.e. pressure campaigns, protests, opposition, and rumours have emerged. In order to mitigate resistance, this thesis proposes ways to enhance participation and deliberation in forest governance. However, the utility of these suggestions is challenged by polarised views and a lack of trust between the different parties. Finally, hypotheses explaining resistance towards decision-making are formulated. Also, contributions to environmental anthropology are outlined, and further questions relevant for research on environmental governance are posed. / Tiivistelmä Uudet ympäristöhallinnan muodot lupaavat parempaa kansalaisosallistumista ja joustavuutta päätöksentekoon. Kuitenkin näitäkin hallinnan muotoja vastustetaan myös Pohjois-Suomen metsiin liittyen. Tässä väitöskirjassa pyritään selittämään vastarintaa metsien hallintaa kohtaan valtion omistamissa talousmetsissä ja suojelualueilla. Väitöskirjassa yhdistetään antropologisia kenttätyömenetelmiä ja ympäristöpolitiikan käsitteitä. Pohjaten teemahaastatteluihin, suunnitteludokumentteihin, lehdistötiedotteisiin ja www-sivuihin tämä väitöskirja määrittää ongelmia hybrideille hallinnan ja päätöksenteon muodoille, jotka koostuvat valtioon, markkinoihin ja kansalaisyhteiskuntaan liittyvien toimijoiden vuorovaikutuksesta. Pohjaten ajankohtaisiin metsäkiistoihin Inarissa, Metsä-Lapissa, Muoniossa ja Liperinsuolla kolme erilaista hallinnan muotoa erotellaan: valtiovetoinen hallinnan muoto, johon kansalaisyhteiskunta linkittyy osallistavien prosessien kautta sekä kaksi ”painostusmuotoa”, jotka koostuvat ympäristöjärjestöjen markkinapohjaisista kampanjoista sekä paikallislähtöisistä protesteista. Mallan, Pallas-Ylläksen ja Oulangan suojelualueisiin liittyen määritellään yksi hallinnan muoto, joka muodostuu puistojen hallinnoista, kansainvälisistä suojelutoimijoista sekä paikallisista luonnonkäyttäjistä. Näitä hallinnan muotoja yhdistää se, että niiden kohtaama vastarinta johtuu paikkakohtaisen päätöksenteon puutteista. Ongelmat liittyvät päätöksentekoprosesseista puuttuviin intressiryhmiin, suunnitteluprosesseissa käytyjen keskustelujen yleisluonteisuuteen, yleispätevien käsitteiden käyttöön standardoimisprosesseissa erityisesti suojelualueilla, läpinäkyvyyden puutteeseen sekä kaukaisten toimijoiden osallistumiseen paikallisiin päätöksiin. Näiden ongelmien seurauksena paikkakohtaisuutta ei huomioida riittävästi hallinnassa, mistä seuraa ’paikan vastaisku’ protestien, huhujen, vastustuksen ja kampanjoiden muodossa. Vastarinnan syntymistä voitaisiin ehkäistä parantamalla osallistumista ja neuvottelua, joskaan parannusehdotuksetkaan eivät ratkaise luottamuksen puutteeseen ja osapuolten näkemysten napaistumiseen liittyviä ongelmia. Väitöskirjassa luodaan hypoteeseja, jotka selittävät ympäristöhallinnan kohtaamaa vastarintaa. Lisäksi väitöskirja tarjoaa antia sekä uusia tutkimuskysymyksiä erityisesti ympäristöantropologialle.
3

The influence of run-off from road networks on aquatic macro-invertebrates in Mamatole commercial tree plantation (Komatiland Forests), Upper Letsitele Catchment, Limpopo Province, South Africa

Diedericks, Gerhardus Johannes 21 August 2012 (has links)
M.Sc. / The purpose of this study was to determine whether unpaved roads in commercial forests have a detrimental impact on aquatic macro-invertebrates in the receiving rivers associated with these roads. The upper section of the headwaters of the Motlhaka-Semeetse River was chosen as the Study Area because a portion is situated in the Wolkberg Wilderness area (natural area with no roads) and a portion in a commercial forestry plantation (high road network density). Stream conditions based on a rapid bio-assessment of aquatic macro-invertebrates using SASS5 were then compared between the two catchments amid 2002 and 2010. In order to support the SASS5 results, daily rainfall data from December 1959 to October 2010 was collated and compared to daily stream flow data from January 1960 to October 2010. In addition, geomorphological and instream habitat changes in the river between the two catchment areas were recorded, as well as the condition of stream crossings and their linkage to stream networks in the afforested catchment. The SASS5 results revealed that stream conditions at the upper unimpaired site were significantly better, visibly and statistically (p < 0.05) than conditions at the lower site within the forestry plantation. In addition, there were noteworthy changes in the catchment hydrology, the geomorphology and instream habitat between the natural and afforested catchments. Road network densities in commercial forests are mostly considerably higher than suggested in literature and exceed stream network densities. Roads increase the surface area for interception of rainfall and the runoff from this high density of roads results in modification of the catchment hydrology, geomorphology and instream habitat of receiving streams. This physical change to the receiving streams is one of the main reasons for the deterioration in SASS5 results, disproving the hypothesis that road networks in forestry areas have no impact on receiving aquatic ecosystems. Commercial forestry in South Africa needs to improve their road planning, layout, management and maintenance to reduce these environmental impacts. In doing so, the road network density will be reduced with considerable environmental and economic benefits.
4

Dinâmica hidrossedimentológica de pequenas bacias hidrográficas florestais / Hidrossedimentology dynamics of small forest watersheds

Rodrigues, Miriam Fernanda 13 October 2015 (has links)
Areas cultivated with eucalyptus forests have increased in Southern Brazil, and the effects on hydrosedimentological processes are not well known particularly at the watershed scale and in watersheds where land use has been changing. The Soil and Water Assessment Tool (SWAT) model has been applied in a few forested watersheds to evaluate and predict effects of commercial forest cultivation or land use change in hydrological processes, whilst erosion processes has not been the main goal. The present study aimed (i) to evaluate the effects of eucalyptus plantation on hydrosedimentological processes, and to evaluate the efficiency and limitations of the Soil and Water Assessment Tool (SWAT) model to simulate streamflow and sediment yield (daily and monthly) in nested eucalyptus watersheds and in two paired watersheds with eucalyptus and grassland, and (ii) to identify the contribution of the bank channel, unpaved roads and eucalyptus stands sediment-sources for two different size fractions of sediment (< 0.063 mm and 0.063-2 mm) deposited along the drainage network, and suspended sediment collected in the outlet of small watersheds. SWAT was used to evaluate hydrological and erosion processes for two nested forest watersheds (watershed-0.98 km2 and sub-watershed-0.39 km2) and two paired watersheds in Pampa Biome, one with grassland (1.10 km2) and other with eucalyptus (0.83 km2). Measured streamflow and sediment yield at the watersheds outlets was used to evaluate model sensitivity to selected model parameters, and for calibration from 2009 to 2013 for nested watersheds, and from 2009 to 2013 for paired watersheds. Time series plots and standard statistical measures were used to verify model predictions. For nested watersheds, predicted monthly streamflow was very good during calibration for the watershed and for the sub-watershed, respectively. Predicted monthly sediment yield was very good and satisfactory for the watershed, and unsatisfactory for the sub-watershed. Simulations for daily time-scale were satisfactory to predict streamflow and sediment yield for the watershed. For the sub-watershed, predicted streamflow was satisfactory , but sediment yield was unsatisfactory . For paired watersheds, predicted monthly streamflow was good during calibration for the grassland watershed and for the eucalyptus watershed. Predicted monthly sediment yield was satisfactory for the grassland watershed, and very good and satisfactory for eucalyptus watershed. Daily simulations were satisfactory to predict streamflow in both grassland and eucalyptus watersheds. The results suggest that the SWAT model is a promising tool to evaluate hydrological processes in Brazilian watersheds. However, more field work with continuous monitoring is required and empirical equations of SWAT must change to better represent the processes that predominate in each watershed and to represent the hydrological and erosion processes in sub-daily time-scale and, especially, for small watersheds where the time of concentration is less than one day. Sediment-sources was evaluated using geochemical properties, determined by inductively coupled plasma mass spectrometry and X-ray fluorescence analyses, and the data used to calculate proportional contributions of sediment. Source contributions were determined at points spatially-distributed along the main channel of the watershed. Source determination for in-stream sites was done using samples collected in one spot to evaluate source-contribution of area upstream of this site of interest to indicate how different sources dominate at different downstream locations. To examine whether different size-fractions shared similar origins, two size fractions of both source and suspended samples including fine (<0.063 mm) and coarse (0.063 2 mm) particles were analyzed. Fingerprinting approach indicated particle-size and location of sources within a watershed are major factors affecting the measured contribution of sources for coarse and fine sediments. The closer a sediment sampling site is to a potential source, the more likely this sediment-source will dominate the sampled material, especially for coarse particles. Based on the classification analysis, the relative contribution of each source to eroded sediments was bank channel, i.e. from the stream network. Modeling results and sediment-source identification can provide an improved understanding effect of land use or change in land use on sediment yield in watershed scale, which are useful and may be used as a management tool of natural resources. / Áreas cultivadas com florestas de eucalipto têm aumentado no Sul do Brasil e os efeitos sobre os processos hidrossedimentológicos são pouco conhecidos, especialmente em escala de bacia hidrográfica e para áreas em que ocorreu mudança no uso do solo. O modelo Soil and Water Assesment Tool (SWAT) tem sido utilizado em bacias hidrográficas florestais para avaliar e simular o efeito do cultivo de florestas comerciais ou mudança de uso do solo sobre os processos hidrológicos, mas os processos erosivos não têm sido avaliados. O presente estudo objetivou (i) avaliar os efeitos do plantio de eucalipto sobre os processos hidrossedimentológicos e a eficiência e as limitações do SWAT em simular o escoamento superficial e produção de sedimentos (diários e mensais) em bacias hidrográficas embutidas, ocupadas com eucalipto, e em duas bacias hidrográficas pareadas ocupadas principalmente com eucalipto e com campo natural, e (ii) identificar a contribuição das fontes margem da rede de drenagem, as estradas e os povoamentos de eucalipto na geração de duas diferentes frações de sedimentos (< 0,063 mm e 0,063-2 mm) depositados ao longo da rede de drenagem, e de sedimentos em suspensão coletados no exutório de bacias embutidas. O SWAT foi utilizado para avaliar os processos hidrológicos e de erosão em duas bacias florestais embutidas (bacia-0,94 km2 e sub-bacia-0,39 km2) e em duas bacias hidrográficas pareadas no Bioma Pampa, uma com campo natural (1,10 km2) e outra com eucalipto (0,83 km2). A vazão e a produção de sedimentos medidas nas seções de monitoramento das bacias hidrográficas foram utilizadas para avaliar a sensibilidade dos parâmetros selecionados do modelo e para calibração para as bacias embutidas (2009-2013), e para as bacias pareadas (2009-2013). As séries temporais e os parâmetros estatísticos foram utilizados para avaliar o potencial preditivo do modelo. Para as bacias embutidas, a representação da vazão mensal foi muito boa durante a calibração para a bacia e para a sub-bacia, respectivamente. A representação da produção de sedimentos mensal foi muito boa e satisfatória para a bacia, e insatisfatória para a sub-bacia. As simulações na escala diária foram satisfatórias para a representação da vazão e da produção de sedimentos para a bacia. Para a sub-bacia, a representação da vazão foi satisfatória, mas da produção de sedimentos foi insatisfatória. Para as bacias hidrográficas pareadas, a representação da vazão mensal foi boa durante a calibração para a bacia com pastagem e para a bacia com eucalipto. A representação da produção de sedimentos mensal foi satisfatória para a bacia com pastagem, e muito boa e satisfatória para a bacia com eucalipto. As simulações diárias foram satisfatórias para a vazão em ambas as bacias pareadas. Os resultados sugerem que o modelo SWAT é uma ferramenta promissora para avaliar processos hidrológicos em bacias hidrográficas brasileiras. No entanto, fazem-se necessários mais tempo de monitoramento contínuo das variáveis hidrossedimentológicas e alteração de equações empíricas do SWAT para melhor representar processos erosivos que predominam em cada bacia e para representar os processos hidrológicos e erosivos em escala sub-diária, especialmente para pequenas bacias em que o tempo de concentração é menor do que um dia. As fontes de sedimentos foram avaliadas por meio do uso de propriedades geoquímicas, determinadas por análises de espectrometria de massas com plasma e de fluorescência de raios-X. A contribuição das fontes de sedimentos foi determinada em pontos espacialmente distribuídos ao longo do canal principal da bacia. Amostras de sedimento de um ponto de coleta foram utilizadas para avaliar a contribuição das fontes da área de contribuição à montante desse local de interesse e para indicar o a diferença da contribuição dessas fontes em diferentes localizações à jusante. Para avaliar se as diferentes frações de sedimentos tem origem semelhante, duas frações de tamanho de partículas das fontes e amostras de sedimento fino (< 0,063 mm) e grosso (0,063-2 mm) foram analisadas. A técnica fingerprinting indicou que o tamanho das partículas e localização das fontes dentro da bacia hidrográfica são os principais fatores que afetam a contribuição das fontes para a produção de sedimentos finos e grossos. As fontes mais próximas do local de amostragem são as potenciais fontes de sedimentos, sendo provável que essa fonte de sedimentos será dominante na amostra de sedimentos, principalmente para as frações grossas. Com base na análise de classificação, a contribuição relativa de cada fonte indicou que a principal fonte de sedimentos foi a margem do canal da rede de drenagem. Os resultados da modelagem e identificação das fontes de sedimentos contribuem para uma melhor compreensão do efeito do uso do solo ou da alteração no uso sobre a produção de sedimentos na escala de bacia hidrográfica, que são úteis e podem ser utilizados como ferramenta de gestão dos recursos naturais.

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