No description available.

Thesis (Ph. D. - Geosciences)--University of Arizona, 1983. / Includes bibliographical references (leaves 168-177).

Annual tree-ring width of Southwestern conifers growing on dry sites exhibits sensitivity to variation in climatically created moisture stress. Douglas-fir, ponderosa pine, and pinyon in the eastern San Juan Basin in northwestern New Mexico and southwestern Colorado were sampled at four sites to investigate covariation of climate with intra-annual anatomy. The sites possessed characteristics that created different amounts of physiological stress in trees. Increment borer samples were glued into wooden mounts and machined to approximately 1.0 mm thickness by a special router-planer. All samples were crossdated by comparing climatically controlled synchronous patterns of ring widths. Moving slit X-ray densitometry (at Forintek Canada Corporation Western Forest Products Laboratory, Vancouver, British Columbia) objectively defined the earlywood zone (large, low density cells) and latewood zone (smaller, denser cells formed late in the growing season) in each ring. The densitometer measured eight parameters for each ring: ring, earlywood, and latewood width, minimum and maximum density, and mean ring, earlywood, and latewood density. Individual radial series were standardized (i.e, transformed to indices with 1.0 mean and homogeneous variance) by fitting curves and dividing annual values by the corresponding curve values. Density series proved more difficult to standardize than widths and usually correlated more poorly among individual radii of the same data data type. Statistical characteristics of site summary density chronologies differed from width chronologies. Response functions using monthly mean temperature and total precipitation showed climate influenced all data types. Low moisture stress increased ring, earlywood, and latewood width and ring, maximum, and latewood density. High moisture stress increased minimum and early— wood density. No width or density type consistently covaried more than any other with climate. Linkage of climatic variation with density parameters differed considerably from that reported in the literature for conifers growing in wetter, cooler climates. Southwestern conifers posed unique densitometric technical difficulties. Selection of sites that caused moderate physiological stress and samples with few missing rings proved critical. Acquisition of density data required much more time and effort than optical measurement of ring width, but yielded valuable intra—annual data. Intra—annual densitometric data hold great promise for reconstruction of seasonal paleoclimate.

Long-lived trees preserve a record of environmental conditions during their lifetime in the pattern of yearly xylem widths and in changing wood density within and among the increments. Crossdated earlywood, latewood, and total ring widths, and minimum earlywood and maximum latewood densities, from three sites in the mountains of Maine, are analyzed visually and statistically to evaluate their relationships to one another and to external, environmental factors which affect the ring width and density through internal, physiological processes. Maximum density values show highest levels of similarity within and among the three site chronologies, thus implying a good degree of sensitivity to climate; minimum density values, however, showed lowest sensitivity to climate. Two biologically reasonable hypotheses concerning climate--tree growth interactions are proposed: (1) that maximum density is related to spring temperatures prior to its formation; and (2) that maximum density is related to summer water relations as the latewood forms. With the help of response function analysis, simple correlation, and multiple linear regression, these two hypotheses are tested: (1) maxmum density as a single predictor explains up to 37% of spring temperature variance; with earlywood widths at one site, 47% of spring temperature variance is explained; (2) maximum density as a single predictor explains up to 45% of summer temperature variance, 11% of summer precipitation variance, and 23% of the variance of Thornthwaite water deficit values; with total ring widths at one site, 22% of the variance of summer stream runoff is explained. Regression equations were applied to the 201- to 310-year tree-ring records to form reconstructions of these past climatic events. Independent verification testing of the reconstructions strongly validates the relationship between maximum density and spring temperature; the relationship to summer water relations is not as strongly verified, but results encourage further testin of this relationship. Results from this study may be applied both to (1) an increased understanding of relationship of climate to the formation of wood density; and (2) further development of dendroclimatology in mesic regions such as northeastern North America.

Thesis (M.S.)--California Polytechnic State University, 2010. / Mode of access: Internet. Title from PDF title page; viewed on April 1, 2010. Major professor: Ann Yelmokas McDermott, Ph.D., M.S., LDN. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree of Master of Science in Kinesiology." "March, 2010." Includes bibliographical references (p. 49-54).

A madeira é considerada como estratégica como produto base para inúmeros setores e segmentos da economia mundial e nacional, para a produção de móveis, pisos, construção, celulose, papel e outros produtos e, ainda, no setor energético, para a produção de álcool, e, em especial no Brasil, para o carvão vegetal, em siderúrgicas. O carvão da madeira de florestas plantadas de eucaliptos traz um maior benefício ao país, pela redução da pressão da exploração da madeira das florestas nativas. A transformação da madeira em carvão ocorre através de tratamento térmico, compreendendo diversas fases de aquecimento, com consequente alteração da madeira, como a perda de água, contração, degradação e ruptura da parede celular dos seus elementos anatômicos. Neste aspecto, são incipientes os estudos das alterações da anatomia da madeira dos eucaliptos resultantes do processo de carbonização e sua aplicação na melhoria da estrutura e da qualidade do carvão. Pelo exposto, o presente trabalho tem como objetivo estudar as alterações da estrutura anatômica, densidade aparente e variação dimensional da madeira e do carvão de árvores de 19 clones/espécies/híbridos de Eucalyptus e Corymbia, de plantações da Aperam Bioenergia Jequitinhonha, da região do Vale do Jequitinhonha/MG. Após a análise anatômica macroscópica e de densitometria de raios X, assim como as medições dimensionais de todos as amostras, a madeira das árvores de Eucalyptus e Corymbia foi submetida ao tratamento térmico de carbonização (450ºC) e, na sequência, aplicados métodos de análise da anatomia microscópica, de densitometria de raios X e de avaliação da contração/redução dimensional. Os resultados das análises anatômicas mostraram que os vasos do lenho próximos da medula e da casca são de menor diâmetro-maior frequência e maior diâmetro-menor frequência, respectivamente, com os clones de maior densidade com menor dimensão-maior frequência dos vasos. A análise microscópica comparada da madeira e do carvão mostrou a alteração dos vasos de formato circular a ovalado-oblongo, redução do diâmetro tangencial e aumento da frequência. Da mesma forma, os resultados indicaram que a densidade aparente da madeira é, de modo geral, 50% maior do que a do carvão. Os clones de madeira e de carvão de maior densidade aparente foram os de C. citriodora e o de C. toreliana x C. citriodora; os de menor densidade aparente foram os de E. urophylla x (E. camaldulensis x E. grandis) e de E. urophylla. Verificou-se, ainda, que a redução/contração da madeira na carbonização foi maior nos sentidos tangencial (26,06%) e radial (15,94%) e nos clones de maior densidade aparente. / Wood is considered as a strategic base product for numerous industries and sectors of the world and national economy, for the furniture production, flooring, construction, pulp, paper and other products, and also in the energy sector for the production of alcohol, and especially in Brazil, to produce charcoal for the steel manufacture. The charcoal from planted forests of eucalyptus brings a greater benefit to the country, by reducing the pressure of the logging of native forests. The transformation of wood charcoal occurs through heat treatment comprising various stages of heating, with consequent alteration of the wood, such as water loss, shrinkage, and degradation of the cell wall rupture of their anatomical elements. In this aspect, are incipient the studies of the wood anatomy changes of eucalypts resulting from the carbonization process and its application in improving the structure and quality of the charcoal. For these reasons, the present work aims to study the changes of anatomical structure, apparent density and dimensional change of the wood and the charcoal from trees of 19 clones/species/hybrids of Eucalyptus and Corymbia plantations from Aperam Bioenergy Jequitinhonha, coming from the region Jequitinhonha Valley/MG. After the anatomical analysis macroscopic and X-ray densitometry, as well the dimensional measurements of all the samples, the wood of Eucalyptus and Corymbia trees was subjected to the heat treatment of carbonization (450° C) and, subsequently, applied methods for the analysis of microscopic anatomy, X-ray densitometry and evaluation of contraction/dimensional reduction. The analysis results showed that the anatomical vessels near the spinal wood and bark are in smaller diameter, higher - frequency and larger-diameter lower frequency, respectively, and clones with higher density has higher frequency and smaller vessels. Microscopic analysis compared the wood and charcoal showed the change in vessels circular shape oblong-oval, reducing the diameter and increasing shear rate. Likewise, the results indicated that the apparent density of the wood is generally 50% greater than that of charcoal. The clones with the highest density were C. citriodora and C. toreliana x C. citriodora, the lower density were E. urophylla x (E. grandis x camaldulensis) and E. urophylla. It was also found that the reduction/shrinkage of the wood after carbonization was greater in the tangential directions (26.06 %) and radial (15.94 %) and in the clones of higher apparent density.

Examination of the relationship between wood properties such as density, cell diameters and climate provides the opportunity to develop long-term climate and mass balance proxies, and is a key component to understanding when and how wood develops through time. This research sought to: create multi-proxy models to represent long-term changes in the climate-mass balance relationships at Place Glacier, and to describe glaciological changes in Mount Revelstoke and Glacier National Parks, British Columbia; use multiple wood properties to develop intra-annual climate records for tree-ring sites from the southern and northern interior regions of British Columbia; and, use climate as an indicator of wood quality by identifying historical climate impacts on wood development over time. Tree-ring samples from hybrid interior spruce (Picea glauca (Moench) Voss x engelmannii (Parry)) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were collected in north-central British Columbia; interior spruce, Douglas-fir, and subalpine fir (Abies lasiocarpa (Hooker) Nuttall) were collected from trees in the Pemberton area of British Columbia, and Engelmann spruce (Picea engelmannii Parry ex. Engelmann), subalpine fir, and mountain hemlock (Tsuga mertensiana Bongard Carrière) were collected from trees located within Glacier and Mt. Revelstoke National Parks. Tree-ring chronologies were constructed using standard ring width measurement techniques, densitometric methodologies, and using SilviScan technology. Relationships among the regional climate, snowpack, mass balance and various wood chronologies were identified and used as a basis for reconstructing proxy climate and mass balance data. A proxy snowpack record for Tatlayoko Lake was reconstructed using mean density and ring width chronologies. Maximum density and ring width chronologies were used to reconstruct winter and summer mass balance records for Place Glacier. Place Glacier was found to respond negatively to continental summer temperature regimes and positively to winter coastal precipitation events. A proxy record of maximum summer temperature was reconstructed for Revelstoke using maximum density and ring width chronologies; while maximum cell-wall thickness was used to reconstruct total August precipitation, and February snowpack from Golden was reconstructed from subalpine fir and mountain hemlock ring-width chronologies. Mass balance for glaciers in the Columbia Mountains was reconstructed using a combination of ring width, maximum density and maximum cell-wall thickness chronologies. The proxy mass balance reconstruction shows a general decline in ice mass over the time span of the net balance reconstruction. Two intra-annual proxy climate records were created for northern British Columbia. Mean June and mean July-August temperature chronologies were reconstructed for Smithers using ring width and maximum density, and for Fort St. James total May-June and July-August precipitation records were reconstructed using ring width, minimum density, and maximum cell-wall thickness. Wood parameters, including density, cell-wall thickness, microfibril angle, and cell diameter in Douglas-fir and interior spruce were reconstructed at five sites across British Columbia using temperature and precipitation data from local climate stations. Maximum cell-wall thickness was shown to be one of the most robust wood parameters to predict using temperature variables. Using a variety of tree-ring characteristics for time series reconstruction provides an opportunity to create multivariate models with greater predictive capabilities that correspond more closely to observed data sets, thereby allowing dendroclimatologists to predict climate data trends more robustly. Because individual wood parameters form at different times throughout the growing season in response to distinct seasonal climates, multiple proxy models allow for the development of intra-annual proxy climate and glaciological records. / Graduate

Thesis (M.S.)--Brigham Young University. Dept. of Exercise Sciences, 2004. / Includes bibliographical references.

A madeira é considerada como estratégica como produto base para inúmeros setores e segmentos da economia mundial e nacional, para a produção de móveis, pisos, construção, celulose, papel e outros produtos e, ainda, no setor energético, para a produção de álcool, e, em especial no Brasil, para o carvão vegetal, em siderúrgicas. O carvão da madeira de florestas plantadas de eucaliptos traz um maior benefício ao país, pela redução da pressão da exploração da madeira das florestas nativas. A transformação da madeira em carvão ocorre através de tratamento térmico, compreendendo diversas fases de aquecimento, com consequente alteração da madeira, como a perda de água, contração, degradação e ruptura da parede celular dos seus elementos anatômicos. Neste aspecto, são incipientes os estudos das alterações da anatomia da madeira dos eucaliptos resultantes do processo de carbonização e sua aplicação na melhoria da estrutura e da qualidade do carvão. Pelo exposto, o presente trabalho tem como objetivo estudar as alterações da estrutura anatômica, densidade aparente e variação dimensional da madeira e do carvão de árvores de 19 clones/espécies/híbridos de Eucalyptus e Corymbia, de plantações da Aperam Bioenergia Jequitinhonha, da região do Vale do Jequitinhonha/MG. Após a análise anatômica macroscópica e de densitometria de raios X, assim como as medições dimensionais de todos as amostras, a madeira das árvores de Eucalyptus e Corymbia foi submetida ao tratamento térmico de carbonização (450ºC) e, na sequência, aplicados métodos de análise da anatomia microscópica, de densitometria de raios X e de avaliação da contração/redução dimensional. Os resultados das análises anatômicas mostraram que os vasos do lenho próximos da medula e da casca são de menor diâmetro-maior frequência e maior diâmetro-menor frequência, respectivamente, com os clones de maior densidade com menor dimensão-maior frequência dos vasos. A análise microscópica comparada da madeira e do carvão mostrou a alteração dos vasos de formato circular a ovalado-oblongo, redução do diâmetro tangencial e aumento da frequência. Da mesma forma, os resultados indicaram que a densidade aparente da madeira é, de modo geral, 50% maior do que a do carvão. Os clones de madeira e de carvão de maior densidade aparente foram os de C. citriodora e o de C. toreliana x C. citriodora; os de menor densidade aparente foram os de E. urophylla x (E. camaldulensis x E. grandis) e de E. urophylla. Verificou-se, ainda, que a redução/contração da madeira na carbonização foi maior nos sentidos tangencial (26,06%) e radial (15,94%) e nos clones de maior densidade aparente. / Wood is considered as a strategic base product for numerous industries and sectors of the world and national economy, for the furniture production, flooring, construction, pulp, paper and other products, and also in the energy sector for the production of alcohol, and especially in Brazil, to produce charcoal for the steel manufacture. The charcoal from planted forests of eucalyptus brings a greater benefit to the country, by reducing the pressure of the logging of native forests. The transformation of wood charcoal occurs through heat treatment comprising various stages of heating, with consequent alteration of the wood, such as water loss, shrinkage, and degradation of the cell wall rupture of their anatomical elements. In this aspect, are incipient the studies of the wood anatomy changes of eucalypts resulting from the carbonization process and its application in improving the structure and quality of the charcoal. For these reasons, the present work aims to study the changes of anatomical structure, apparent density and dimensional change of the wood and the charcoal from trees of 19 clones/species/hybrids of Eucalyptus and Corymbia plantations from Aperam Bioenergy Jequitinhonha, coming from the region Jequitinhonha Valley/MG. After the anatomical analysis macroscopic and X-ray densitometry, as well the dimensional measurements of all the samples, the wood of Eucalyptus and Corymbia trees was subjected to the heat treatment of carbonization (450° C) and, subsequently, applied methods for the analysis of microscopic anatomy, X-ray densitometry and evaluation of contraction/dimensional reduction. The analysis results showed that the anatomical vessels near the spinal wood and bark are in smaller diameter, higher - frequency and larger-diameter lower frequency, respectively, and clones with higher density has higher frequency and smaller vessels. Microscopic analysis compared the wood and charcoal showed the change in vessels circular shape oblong-oval, reducing the diameter and increasing shear rate. Likewise, the results indicated that the apparent density of the wood is generally 50% greater than that of charcoal. The clones with the highest density were C. citriodora and C. toreliana x C. citriodora, the lower density were E. urophylla x (E. grandis x camaldulensis) and E. urophylla. It was also found that the reduction/shrinkage of the wood after carbonization was greater in the tangential directions (26.06 %) and radial (15.94 %) and in the clones of higher apparent density.

A dissertation submitted in full compliance with the requirements for the M.Tech: Radiography,Durban University of Technology, 2006. / The aim of this research was to determine normal bone mineral density (BMD) reference ranges (means and standard deviations) for the lumbar spine, total hip and distal forearm, for Indian women of varying age groups in KwaZulu-Natal. The aim also included a comparison of the study population reference ranges with those provided by the manufacturer in order to evaluate any diagnostic implications. / M