Dissertations / Theses on the topic 'Exotic plantation'

Riparian buffers along stream margins have been widely adopted as a management strategy to mitigate the adverse effects of plantation forestry on stream ecosystems. However, the efficacy of these riparian buffers can be jeopardised by variations in width, length, and vegetation which can range from native and exotic scrub (including bracken, gorse, broom and blackberry) to remnant beech forest. This thesis investigates the influence of riparian vegetation age and composition, on stream ecosystems within exotic pine plantations. Initially, a survey of 50 streams within pine forests of various ages and riparian composition was conducted at sites from mid-Canterbury to Hanmer Springs over the summer of 2004-2005. Additionally, terrestrial subsidies were compared between young pine, mature pine and indigenous forest streams to ascertain differences or similarities between vegetation types. A range of physico-chemical and biological characteristics were recorded, while vegetative age and composition with catchment, riparian buffer and reach scales were determined using GIS. Forestry activities were found to vary temporarily and tended to adversely impact upon streams where riparian buffers were narrow and lacked indigenous vegetation. Stream instability and sedimentation were consistently higher in catchments lacking indigenous riparian vegetation, and more markedly so in recently harvested catchments compared with more mature forests. Streams dominated by pine forests had finer substrates with higher water temperatures and levels of turbidity, while those dominated by indigenous forest had coarser substrates, higher flows and dissolved oxygen levels, and less in-stream debris. Benthic community composition was similar among sites, although taxonomic richness, EPT diversity, and invertebrate abundances were enhanced by indigenous riparian vegetation.

Today's arid and semi-arid zones of the Mediterranean are affected by desertification, resulting from various factors, including climatic variations and human activities such as overcultivation, overgrazing and deforestation. Afforestation programs are one of the most effective means in preventing desertification. For many years Libya has had afforestation programs in order to restore degraded land and in response to rapid desert encroachment in the north east of Libya, in the area called the Jabal Akhdar (Green Mountain), which has been investigated in this study. The purpose of this research was to investigate the relative roles of exotic compared to native tree species in preventing desertification and enhancing degraded land restoration in the Jabal Akhdar. The effect of environmental factors on exotic compared to native tree species have been assessed by observations on growth and reproductive success of the species, including variables of stocking rate, trunk diameter, tree height, crown diameter, tree coverage, natural mortality, felling and seedling regeneration, as well as calculated variables, derived from these measurements. The effects of methods and age of afforestation on the promotion of biological diversity have been investigated using the Shannon-Wiener diversity index. The effects of tree species on soil depth have also been investigated. Multivariate statistical analyses of site, species and environmental data, using both cluster analyses and factor analyses have been performed, with the aim of determining what is influencing the species, crops or differentiating between the sites, based on soil depth, angle of slope, altitude, rainfall and air temperature values. Pinus halepensis showed success in its growth and regeneration, particularly at higher altitudes and steeper slopes. Cupressus sempervirens was successful in growth and regeneration in the mountains. The exotic Eucalyptus gomphocephala was very successful in its growth, but did not regenerate well, while the exotic Acacia cyanophylla trees had a failure of both growth and regeneration. E. gomphocephala species appeared to favour relativley the flatter (non-mountain) sites, while A. Cyanophylla appeared to favour relativly the mountain sites. All the species responded positively to greater rainfall and deep soil, but they differed in where they were most likely to be successful. Environmental factors such as climate, terrain and soil are the main determinants of species distribution in the study area, in addition to their impact on the growth of the main trees. There appeared not to be any relationship between biodiversity and whether the main trees were native or exotic, and only P. halepensis showed any negative effect on the abundance of shrubs. There was greater diversity of trees and shrubs generally at the younger sites than the old sites. The present study emphasises the current mismanagement of planted forests, particularly with overgrazing contributing to desertification, through preventing tree growth and eliminating most sapling regeneration. This study concludes by making recommendations for more effective choice of tree species to plant, and for subsequent management to improve afforestation programmes in the Jabal Akhdar area.

Aboveground and belowground ectomycorrhizal (ECM) communities associated with different age classes of the exotic plantation species Pinus radiata were investigated over the course of two years in the North Island of New Zealand. ECM species were identified with a combined approach of morphological and molecular (restriction fragment length polymorphism (RFLP) and DNA sequencing) analysis. ECM species richness and diversity of a nursery in Rotorua, and stands of different ages (1, 2, 8, 15 and 26 yrs of age at time of final assessment) in Kaingaroa Forest, were assessed above- and belowground; furthermore, the correlation between the above- and belowground ECM communities was assessed. It was found that the overall and stand specific species richness and diversity of ECM fungi associated with the exotic host tree in New Zealand were low compared to similar forests in the Northern Hemisphere but similar to other exotic plantations in the Southern Hemisphere. Over the course of this study, 18 ECM species were observed aboveground and 19 ECM species belowground. With the aid of molecular analysis the identities of Laccaria proxima and Inocybe sindonia were clarified. In the aboveground study, five species were found associated with P. radiata that were previously not reported with this host in New Zealand (Inocybe sindonia, Lactarius rufus, Lycoperdon gunii, Rhizopogon pseudoroseolus and Wilcoxina mikolae). Belowground, the species Psudotomentella sp., P. tristis, R. luteorubescens, Tomentella sp., Wilcoxina mikolae were found as new associates of P. radiata in New Zealand, additionally nine ECM types were found that could not be identified with molecular analysis. There was little correlation between the species fruiting and the species colonising root tips. Only seven species were found in common between the above- and belowground communities, furthermore the dominant species aboveground were not observed in the belowground ECM communities. The influence of host age on the above- and belowground ECM communities of different age classes of P. radiata plantations was investigated. The aboveground species richness increased from the nursery to the oldest age group investigated (26 yrs), while diversity increased to the 15 yr old age group and decreased slightly to the oldest stand. A clear sequence of ECM species changes was observed to be related to stand age with a growing complexity over the chronosequence. The belowground ECM communities showed a different picture and richness and diversity initially decreased from the nursery to the outplanting but increased thereafter. Belowground no change in ECM composition that was directly related to the age of the host was observed, but two distinct groups of ECM species were found – a 'young' and a 'plantation forest' group, with the respective discriminating species being Rhizopogon rubescens and Type unknown Basidiomycete/Amanita muscaria. Another aspect of the study was the fate of the nursery ECM species in the outplanting and the arrival of non-nursery species. The ECM communities of seedlings in the nursery were investigated in 2006 and these seedlings were followed up over eight assessments in the field for one year, furthermore data from the 1-, 2 and 8 yr old plantation stands was analysed. It was found that the nursery species do survive the first year of outplanting and are dominant in the first year. The first non-nursery species occurred six months after outplanting but was only in minor abundance. Nursery ECM were dominant for two years after the seedlings were planted, and were completely replaced after seven years. Rhizopogon rubescens was found to be the most persistent and dominant species in the outplanting, facilitating the successful establishment of the seedlings in the plantation forest.

Forest plantations, widely grown for wood production, involve the selective promotion of single tree species, or replacement of natural species by exotic tree species. Slash pine (Pinus elliottii) has been chosen for reforestation of infertile sandy soils in southeast Queensland, Australia. These exotic pine plantations minimise soil and water losses, and are important scientific study sites. The soil environment of these plantations, though devoid of sufficient nutrients, oxygen and other factors, harbours innumerable bacteria that may play a crucial role in maintaining soil quality and ecosystem functions. These soil microorganisms also have the potential for use as sensitive biological indicators to reflect environmental changes. It is therefore essential to understand the interrelationships amongst bacterial communities and their environment by assessing their structural and functional diversity, and their responses to disturbances. The microbial community of an exotic pine plantation of subtropical Australia was analysed by both culture-dependent and culture-independent methods. In this study, a leaf litter-soil core sample (25 cm x 40 cm) was collected from a 22-year-old slash pine plantation in southeast Queensland, Australia in October, 2003. The core sample was divided into three fractions, namely, L layer leaf litter, F layer leaf litter, and forest soil 0-10 cm. In the culture-independent study, a modified DNA extraction and purification method was used to obtain highly purified high-molecular-weight DNA. This DNA was successfully used to amplify bacterial 16S rRNA genes with universal primers Fd1 and R6, to produce products of approximately 1500 bp. PCRamplified 16S rRNA genes were subsequently cloned and a total of 194 clones from leaf litter and soil were partially sequenced (about 510 bp). The 16S rRNA gene sequences were analysed and grouped into several phylogroups (the sequences with a similarity value ¡Ý 98 % were regarded as phylogenetically similar and grouped into one phylogroup). Sequencing representatives (¡Ö 1400 nucleotides) from each phylogenetic group confirmed that five bacterial phyla were represented in the forest soil clone library. Phylum Acidobacterium was the most abundant phylogenetic group in terms of the number of clones and accounted for 42 % of all examined soil clones. The Verrucomicrobiales and Proteobacteria were the second and third most abundant phylogenetic groups found in the soil clone libraries, accounting for 12 % and 11 % of the soil clones, respectively. About 8 % of all examined soil clones were Planctomycetes and 27 % of soil clones were phylogenetically unidentified. The large amount of unclassified clone sequences could imply that novel groups of bacteria were present in the forest soil. When the two fractions of leaf litter clone libraries were compared, Firmicutes was the only phylum represented in the L layer leaf litter clone library. Similarly, Firmicutes dominated the F layer leaf litter (79 % of the library), was followed by Proteobacteria (21 %). For the culture-dependent study, a total of 21 isolates which were considered to represent 334 colonies from the leaf litter and forest soil were identified by 16S rRNA gene sequence analysis, indicating that L layer leaf litter and F layer leaf litter were dominated by Firmicutes (48 %) and Proteobacteria (69 %) respectively, and 91 % of the isolates from the forest soil were Firmicutes. Using culture-independent methods, Actinobacteria appeared to be absent from the L and F layer leaf litter and forest soil samples. The results implied that either the nucleic acids of Actinobacteria were difficult to extract or Actinobacteria were over represented in the culture-dependent examinations. Phylum Acidobacteria appeared to be numerically dominant and active members in most soils. However, only one named species had been isolated from an acid mine drainage site and reported by Kishimoto and Tano (1987). Analysis by culture-dependent methods revealed a different bacterial diversity, compared to the bacterial diversity from the 16S rRNA gene clone sequences. The most significant result was the observation that, as revealed by both culture-dependent and culture-independent methods, the bacterial diversity presented in the leaf litter was greatly different from the community of the soil. During the culture-dependent bacterial diversity study, four novel strains were isolated from the forest soil and leaf litter samples and complete characterisations of these novel strains were carried out. Reports on the descriptions of Bacillus decisifrondis strain E5HC-32T from forest soil and Frondicola australicus strain E1HC-02T from L layer leaf litter have been published (appendix). The information provided by assessing the microbial communities in different fractions of leaf litter and forest soil improves our understanding of the phylogenetic relationship between soil and leaf litter. It is suggested, in this study, to perform both culture-dependent and culture-independent methods to characterise the bacterial structure and diversity in forest litter and soil samples, particularly in response to different forest management practices and global change. This study also provides the basis for further functional studies of the forest soil and leaf litter of exotic pine plantation in subtropical Australia.

Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia. Universidade de Lisboa
Eucalypt plantations expanded across many countries and became subject to controversy, particularly about their ecological impacts and invasive potential. The same is true in the Iberian Peninsula (Iberia) regarding Eucalyptus globulus Labill. This thesis is composed by six studies (chapters) tackling poorly explored aspects in these domains, with the following objectives: a) to evaluate potential future dynamics of E. globulus plantations in Iberia according to different climate change scenarios and possible conflicts with high biodiversity areas (Chapter 1); b) to explore the influence of different factors on the natural establishment of E. globulus (Chapters 2-5); c) to perform a review of the literature investigating the natural establishment of eucalypt species (Chapter 6). In Iberia, under both climatic scenarios, the suitable range of E. globulus plantations is expected to shrink and conflicts with high biodiversity areas may aggravate (Chapter 1). A countrywide survey in Portugal to estimate E. globulus recruitment, using Google Street View, showed that recruitment is mostly influenced by climatic variables (annual precipitation and thermal amplitude) and that Google Street View is a cost-efficient alternative to car surveys (Chapter 2). Field surveys in E. globulus plantations in Central Portugal showed abundant recruitment along plantation edges, influenced by local factors such as soil cover and tree age. Wildlings, mostly adult, are spread up to 76 meters from plantations (Chapter 3). A sowing experiment using E. globulus seeds showed that germination and survival was enhanced after harrowing (Chapter 4). A seed predation experiment revealed that E. globulus seeds are highly attractive but they have escaped in many locations (Chapter 5). The literature review retrieved 37 studies, addressing 61 eucalypt species in seven countries. Key factors influencing eucalypt recruitment include fire, propagule pressure and disturbances (Chapter 6)
N/A

Natural forests are characterised by great vegetation diversity and create habitats for a major part of Earth’s terrestrial organisms. Plantation forests, which are mainly composed of a few genera of fast-growing trees, constitute an increasing fraction of global forests, but they only partly compensate for loss of area, habitat and ecological functions in natural forests. Plantation forests established near natural forests can be expected to serve as buffers, but they seem to be relatively poor in invertebrate species and it is not clear why. This bachelor’s degree project aimed at establishing the ecological and edaphic factors that correlate with soil invertebrate diversity in dry upland forests and surrounding plantation forests in eastern Africa. Some aspects of the above-ground vegetation heterogeneity were investigated since this was assumed to influence the heterogeneity of the soil environment, which is considered as critical for soil biodiversity. The obtained knowledge may be valuable in conservation activities in East African forests, which are threatened by destruction, fragmentation and exotic species. The study area was Karura Forest, a dry upland forest in Nairobi, Kenya. Three different sites were investigated; a natural forest site characterized by the indigenous tree species Brachylaena huillensis and Croton megalocarpus, and two different plantation forest sites, characterized by the exotic species Cupressus lusitanica and Eucalyptus paniculata, respectively. For each forest type, six plots were visited. Soil invertebrates were extracted from collected soil and litter samples by sieving and Berlese-Tullgren funnels. The invertebrates were identified, and the taxonomic diversity calculated at the order level. The ecological and edaphic factors, measured or calculated for each plot, were tree species diversity, ratio of exotic tree species, vertical structure of trees, vegetation cover, vegetation density, litter quality, soil pH, soil temperature and soil moisture. One-way ANOVA was used to compare soil invertebrate diversity and other variables between different forest types. Akaike’s Information Criterion and Multiple Linear Regression were used to establish linear models with variables that could explain measured variations of the diversity. There was some evidence for higher soil invertebrate diversity in natural forests than in surrounding plantation forests. The abundance of soil invertebrates was also clearly higher in natural forests, which indicates that natural forests are more important than plantation forests for conservation of soil invertebrate populations. Soil invertebrate diversity (in terms of number of orders present) was found to be influenced by forest type and litter quality. The diversity was higher at places with high amounts of coarse litter, which here is considered as more heterogenous than fine litter. The dependence on forest type was partly a consequence of differences in soil pH since Eucalyptus trees lower soil pH and thereby also soil biodiversity. No relation to heterogeneity of above-ground vegetation was found. For future conservation activities in Karura Forest Reserve it is recommended to continue removing exotic plant species and replanting indigenous trees, to prioritize the removal of Eucalyptus trees before Cypress trees, to only remove a few trees at a time and to establish ground vegetation when doing so.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第22477号
農博第2381号
新制||農||1074(附属図書館)
学位論文||R2||N5257(農学部図書室)
京都大学大学院農学研究科森林科学専攻
(主査)准教授 舘野 隆之輔, 教授 北島 薫, 教授 德地 直子
学位規則第4条第1項該当

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Objetivou-se avaliar o desempenho silvicultural de 18 clones do gênero Eucalyptus em duas condições edafoclimáticas diferenciadas, do estado de Mato Grosso. Os plantios experimentais foram instalados em 2010 no delineamento de blocos ao acaso com quatro repetições. Avaliou-se a altura total, altura dominante, DAP, área transversal média, área basal, e a morfometria de copa dos 18 clones nas duas regiões. Os dados obtidos foram submetidos a análise de variância e, posteriormente, teste de média de Scott-knott a 1% de probabilidade. Comportamento distinto foi encontrado entre os materiais testados nas áreas avaliadas. Os clones que apresentaram características superiores em Sinop foram os S-0102, S-0206 e S-0302em Chapada dos Guimarães foram os S-0410, S-0411, S-0412. O clone S-0402 apresentou características silviculturais superiores nas duas regiões de estudo.
This study aimed to evaluate the silvicultural performance of 18 clones of Eucalyptus in two different soil and wheather conditions, in the state of Mato Grosso.The experimental plantings were installed in 2010, with a randomized block design with four replications. It was evaluated the total height, dominant height, DBH, average cross-sectional area, basal area, and the morphometry canopy of the 18 clones in the two regions. The data obtained were subjected to analysis of variance and, subsequently, to the average test of Scott-Knott 1% probability. Distinct behaviors were found among the materials tested in the evaluated areas. The clones that showed superior characteristics in Sinop were the S-0102, S-0206 and S-0302 and Chapada dos Guimarães were the S-0410, S-0411, S-0412. The S-0402 clone presented sivicultural characteristcs superior in both study areas.

碩士
國立中興大學
國際農學碩士學位學程
105
Abstract Exotic plantation forests have high biomass and contribute to significant economic impact of many countries in the World. This is due to the fact that the species have an ability to grow very fast in introduced areas compared to many native species. However, they might also escape from plantations through seeds regeneration and spread into natural habitats. Their expansion outside plantation may have huge negative impacts on biodiversity and ecosystem functioning, and thus has become a major concern for many scientists. The major planted species worldwide are eucalyptus, pines and cypress. This study aimed to investigate the regeneration potential of four exotic planted species (i.e., Eucalyptus grandis, Pinus kesiya, Pinus caribaea and Cypress lustanica) at the Sao Hill forest plantation, Tanzania and try to record any evidence of self-regeneration of the species into its adjacent natural areas. The study proposed that: “if these species can withstand conditions of plantation areas where no prior treatment of soil, watering, or fertilizer applications, may have the potential to have natural regeneration into natural areas upon plantation escape”. The study was done by conducting censuses of all regenerated exotic individuals into both plantation and natural areas. In total, there were 4 districts (with 12 transects). Three line transects were set up at each district. The distance from plantation boundary was 100 m and 200 m in plantation and natural areas, respectively. The study found that the species have self-regenerated and have the potential of becoming invasive. Three species (i.e., Eucalyptus grandis, Pinus kesiya, and Cypress lustanica) were found into both plantations and natural areas, while few individuals of Pinus caribaea were recorded. The results further showed a positive skewness trend of individual recruits towards natural areas. The majority of the individual recruits were found close to the plantation edge. Moreover, results on maximum diameter at breast height (DBH) on individual recruits showed that, individual’s diameter in two species (i.e., Eucalyptus grandis, Pinus kesiya,) increased with distance from plantation boundary and thus indicating severe invasive potential. Thus, having seen the successful natural regeneration of the species, this study urges further studies to identify traits of species related to invasion and composition of native forests. Nevertheless, identifying the details of germination ability and processes associated with seeds dispersal, seedling survival and mortality are crucial. The current results of this study can help plantation managers to easily identify fast spreading species into natural areas and thus, take responsible measures of control.

碩士
東海大學
生命科學系
95
Abstract (ch1) Predation effects could be achieved by directly reducing prey abundance and by indirectly via altering behavioral patterns of prey. In the past, there was little evidence that ant community structure composition could be affected by vertebrate predations. Researchers tend to consider the interactions between vertebrate predators and ants to be weak. In this study, we examined the impacts of the exotic invasive lizard, Anolis sagrei, on ant community structure by manipulating the density of lizards by enclosures. The natural density of A. sagrei in the field was surveyed and used as the density in the lizard-present subenclosures. Before lizard density was manipulated, there was no difference in ant diversity between subenclosures. After lizard density manipulation the ant diversity in subenclosures with A. sagrei present was significantly different from that of enclosures without, although overall ant abundance did not differ significantly. The ant diversity difference was generated by abundance change of ant species Pheidole fervens due to predation pressure of A. sagrei. A significantly lower P. fervens in subenclosures with A. sagrei present might result from direct predation of lizards, or was generated by foraging site shift of this ant. Results of this study thus demonstrated that the invasion of an exotic vertebrate could significantly alter the community structure of ants via predation. Abstract (ch2) Litter decomposition rate is an important factor affecting nutrient recycling in the detritus ecosystem. Collembola are among the most abundant micro-detritivores in leaf litter and play the key roles in the functioning. Collembola influence the litter decomposition rate directly by feeding on litters and indirectly by consuming the fungi involved in the detritus recycling process. Ground spiders such as the family Lycosidae is the major predator of collembola and some genera of ants also take collembola as major prey resource. In this study, we established enclosures to manipulate the density of an invasive lizard, Anolis sagrei, to determine whether the introduction of this lizard would indirectly affect collembola abundance and diversity by predating their predators such as ants and spiders, and consequently affecting litter decomposition rate. We surveyed the natural density of A. sagrei and used that as the density in lizard-present subenclosures. After the manipulation, the overall ant abundance did not differ between two lizard-present and lizard-removed subenclosures. The abundance of Strumigenys ant, the collembola specialist, was very low, so its impact on collembola could not be assessed. After lizard density manipulation although the abundance of jumping spiders (Salticidae) differed significantly, that of the major spider predator of collembola, the wolf spider (Lycosidae), showed no significant change. Neither abundance nor diversity of collembola differed significantly between two types of subenclosures. Congruent with such results were the litter decomposition rates, which also showed no significant differences. Results of this study showed that although presence of the invasive A. sagrei altered ant community structure, this lizard did not significantly affect major predators of collembola and thus collembola abundance and consequently litter decomposition was not impacted.