Thesis (Ph. D.)--Institute of Paper Chemistry, 1962. / Includes bibliographical references (p. 87-88).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1978. / Includes bibliographical references (p. 146-151).

Managed pine forests are central to the economic vitality of the southeastern US. Over the past fifty years, the productivity of managed pine forests of this region have increased significantly with the development of new silvicultural technologies and the use of improved tree genetic material. Of the pine species present in the southeastern US, loblolly pine has arguably been the most intensively studied and widely planted by forest managers. Efficient operational deployment of improved genetic materials requires an understanding of how possible site conditions and silvicultural treatment may interact to affect maximum yield. There are a wide range of site conditions in the south as the result of regional climate gradients, soil type and soil drainage patterns. On the western edge of loblolly pine’s natural extent, Texas has a drier climate than areas to the east, and in Louisiana, there are also poorly drained Ultisols that are found in areas with little relief and are prone to flooding. However, on the basis of 10-year forest inventory data of pure-family plots from three different sites and under two levels of cultural regime intensity, my study found that superior genotype, Lob 5 from South Carolina, still showed best performance in the Western Gulf area, and high intensive treatment could improve stand growth and resistance to wind damage significantly. Further, my study compared the stand production and dynamics between pure- and mixed-family plots. I found that Lob 5 and Lob 4 showed the growth traits of competitive ideotype, and low intensive treatment increased the deployment effect significantly for competitive ideotype. Finally, my study examined leaf area index (LAI) and foliar nitrogen concentration (foliar N). The result showed that fast growing genotype had lower LAI and foliar N than slow growing one. It indicated that fast growing genotype had high resource use efficiency and nutrient requirement. This research provided critical information to guide industrial forest management in the WG (Western Gulf) area. First, introduced superior genotype continued to show good performance in this area. Second, combination of good genotype and high intensive treatment would increase plantation production significantly. Third, identification of ideotype would increase the accuracy of growth potential estimation in progeny test.

Loblolly pine (Pinus taeda L.) is an ecologically and economically important southern pine, distributed across the southeastern United States. Its genetic improvement for breeding and deployment is a major goal of the Western Gulf Forest Tree Improvement Program (WGFTIP) hosted by the Texas A&M Forest Service. Rapid advances in genomics and molecular marker technology have created potential for application of Marker Assisted Selection (MAS) and Genomic Selection (GS) for accelerated breeding in forest trees. First-generation selection (FGS) and second- generation selection (SGS) breeding populations of loblolly pine from east Texas were studied to estimate the genetic diversity, population structure, linkage disequilibrium (LD), signatures of selection and association of breeding traits with genetic markers using a genome-wide panel of 4264 single nucleotide polymorphisms (SNPs). Under- standing the genetic basis of local adaptation is crucial to disentangle the dynamics of gene flow, drift and selection and to address climate change. Bayesian mixed linear models and logistic regression were used to associate SNP variation with geography, climate, aridity and growth season length and markers with strong correlations were investigated for biological functions. Relatively high levels of observed (Ho = 0.178–0.198) and expected (He = 0.180-0.198) heterozygosities were found in all populations. The amount of inbreeding was very low, and many populations exhibited a slight excess of heterozygotes. The population substructure was weak, but FST indicated more pronounced differentiation in the SGS populations. As expected for outcrossing natural populations, the genome-wide LD was low, but marker density was insufficient to deduce the decay rate. Numerous associations were found between various phenotypes and SNPs, but few remained significant after false positive correction. Signatures of diversifying and balancing selection were found in markers representing important biological functions. Strong correlations supported by Bayes factors were found between various environmental variables and several SNPs. Logistic regression found hundreds of significant marker-environment associations, but none remained significant after false-positive correction, which was likely too stringent and will require further investigation. Annotations of significant markers implicated them in crucial biological functions. These results present the first step in the application of MAS to the WGFTIP for loblolly pine genetic improvement and will contribute to the knowledgebase necessary for genomic selection technology. Results from environmental association study provide important information for designing breeding strategies to address climate change and for genetic conservation purposes.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 60-64). Also available via the Internet.

Thesis (M.S.)--Auburn University, 2004. / Abstract. Vita. Includes bibliographical references.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 177-190). Also available via the Internet.

Thesis (Ph.D.)--Mississippi State University. College of Agriculture and Life Sciences. / Title from title screen. Includes bibliographical references.

Orientador: Raquel Gonçalves / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-04T02:41:40Z (GMT). No. of bitstreams: 1 Neri_AntonioCarlos_D.pdf: 2011024 bytes, checksum: f186a3983118cb93726e980979e74b80 (MD5) Previous issue date: 2003 / Resumo: As madeiras de reflorestamento têm grande importância na economia nacional, movimentando importantes setores, tais como os de papel e celulose, de recursos energéticos, moveleiros e de construção civil. Embora o Brasil apresente um grande potencial florestal, sendo detentor das maiores reservas florestais tropicais do mundo e possuindo condições de clima e solo favoráveis à implantação de florestas de rápido crescimento, sua participação no comércio internacional de madeiras (2,1%) é, ainda, muito pequena. Em geral, grande parte das indústrias que processam madeiras apresenta baixo rendimento de madeira serrada e qualidade insuficiente do produto final, principalmente devido ao emprego de técnicas de processamento (conhecimento de parâmetros de corte) além de fatores de planejamento da serraria (implantação e Layout) inadequadas. Esse fato revela, portanto, que o setor madeireiro necessita incorporação de inovações tecnológicas. A caracterização de espécies de reflorestamento, no que diz respeito aos parâmetros de usinagem, tais como forças de corte, geometria adequada da ferramenta, espessura de corte, densidade, etc., é imprescindível no processamento da madeira. O objetivo principal deste trabalho foi a determinação dos principais parâmetros de corte (forças de corte, pressão específica de corte e ângulo ideal de saída da ferramenta) para a espécie Pinus taeda, mediante o estudo do comportamento das forças de corte em diferentes posições e regiões de madeira juvenil e adulta do tronco. Além desse objetivo, o trabalho pretendeu, também, avaliar a metodologia de determinação de forças de corte para as espécies de eucalipto (Citriodora, Saligna e Grandis), proposta pelo autor em trabalho anterior. Para alcançar esses objetivos, foram ensaiados 96 corpos-de-prova da espécie Pinus taeda, obtidos de seis árvores provenientes do horto florestal de Manduri, S.P, com um total de 5760 ensaios. Como resultado, para o Pinus taeda foram determinadas as forças em função dos parâmetros espessura de corte e ângulo de saída, bem como foi calculado o ângulo de saída x ideal, que resultou da ordem de 40° para pequenas espessuras de corte e da ordem de 30° para maiores espessuras. Para as espécies de eucalipto (Citriodora, Saligna e Grandis), cujos resultados experimentais foram obtidos pelo autor em trabalho anterior, bem como para o Pinus taeda, foi calculada a pressão específica de corte. Os resultados permitiram, ainda, comprovar que a metodologia avaliada é adequada para utilização na espécie estudada / Abstract: The reforestation wood has great importance in the national economy, running important sectors, such as paper and the cellulose, energy resources, furniture and civil construction. Although Brazil presents a great forest potential, holding the biggest forest reserves of the world and possessing soil and climate conditions favorable to the implantation of forests of fast growth, its participation in the wood international trade (2.1%) is, still, very small. The techniques currently used in processing the wood, usually do not provide good income, neither propitiate good quality in the final product as well. Mainly due to the usage of inadequate parameters of the cutting process, along with inappropriate sawmill planning (implantation and Layout). This fact discloses, therefore, that the lumber sector needs the incorporation of technological innovations. The characterization of kinds of reforestation that respect the cutting parameters, such as, cutting force, adequate geometry of the tool, cutting thickness, density, etc., is essential in the processing of the wood. The main objective of this work was the determination of the main parameters of cutting (cutting force, specific cutting force and ideal exit angle of the tool), for the species of loblolly pine (Pinus taeda L.) by the study of the behavior of the cutting force in different positions of the trunk and in different regions of juvenile and adult of wood. Beyond this objective, the work is intended, also, to evaluate the methodology of determination of cutting force for the wood of eucalyptus, proposed by the author in previously work. To reach these objectives, 96 specimens of the specie Pinus taeda were assayed, taken from 6 trees proceeding from a research forest of Manduri, S.P, resulting in 5760 tests. As a result, the force as function of the evaluated parameters had been determined for Pinus taeda, as well, the ideal cutting angle for specimens thickness environ 0.2 mm was near 40° and for thickness between 0.4 mm and 1.0 mm was near 30°. The specific cutting force was calculated for Pinus taeda, as well as for the Eucaliptus. The former with experimental results obtained in this work and the latter using experimental results obtained in previous work from the author. Finally, the results had proved also that the methodology adopted in this research is appropriated to use in the studied species / Doutorado / Construções Rurais / Doutor em Engenharia Agrícola

Loblolly pine (Pinus taeda) and coppiced sweetgum (Liquidambar styraciflua) seedlings were grown in competition with a native weed community using soil and seed bank collected near Appomattox, Virginia. Seedlings and weeds were exposed to CO₂ (ambient and elevated) and water (water stressed and well watered) treatments for approximately one growing season in closed top chambers. Weed growth had an effect on tree growth, but the amount of variation in tree biomass explained by weed biomass was very low. It appears that the tree seedlings benefited more from available resources than the herbaceous weeds. The influence of competition with loblolly pine and elevated CO₂ did not have an influence on total weed biomass; however, it did favor C3 weed community development regardless of water availability. This suggests that weed community composition may shift toward C₃ plants in a future elevated CO₂ atmosphere. Loblolly pine height, diameter, needle, shoot and total biomass were significantly greater in the well watered treatment than the water stressed treatment. Pine root, needle, shoot and total biomass were significantly greater in the elevated treatment than the ambient treatment. While not significant, root biomass of water stressed pine seedlings was 63% greater in the elevated CO₂ treatment than the ambient treatment. There was a significant water and CO₂ interaction for pine root:shoot ratio. Under elevated CO₂, root:shoot ratio was significantly greater in the water stressed treatment than the well watered treatment. In contrast, root:shoot ratio in the ambient treatment was nearly identical under both water treatments. These results indicate that loblolly pine will respond favorably in an elevated CO₂ atmosphere, even under dry conditions. The coppiced sweetgum seedlings responded favorably to well watered conditions with significant increases in leaf area, specific leaf area, leaf, shoot and total biomass compared to water stressed conditions. Leaf, root, shoot+stump and total biomass of sweetgum significantly increased and specific leaf area decreased under elevated CO₂ compared to ambient CO₂, but differences were smaller than previous findings. This indicates that coppicing may dampen the growth response to elevated CO₂, at least in the initial growth stage after coppicing. / Master of Science