Trees of Slash pine showed reduced growth, by an order of magnitude, following exposure to two hurricanes (Elena and Kate) in 1985. The reduced growth is caused by salt spray chlorosis and/or defoliation from high winds. Ring width, radial tracheid diameter, radial cell number, tracheid length and microfibril angle were measured for samples from before and after major storms. Data for ring width, earlywood radial cell diameter and cell number were not normally distributed, while data for latewood radial cell diameter, tracheid length and microfibril angle showed normal distributions. There were significant statistical differences for all main effects for ring width, earlywood radial cell diameter, cell number and tracheid length. The data for latewood radial cell diameter show significant differences for effects of time and height, but not for compass direction. There are significant differences in earlywood cellulose microfibril angle for height effects, and no difference for time and direction effects. Data for latewood cellulose microfibril angle show significant differences for the effects of time and height. / Source: Dissertation Abstracts International, Volume: 55-01, Section: B, page: 0016. / Major Professor: Loran C. Anderson. / Thesis (Ph.D.)--The Florida State University, 1993.

Abstract not available.

In the past two decades, China has achieved a spectacular success in its economic growth. As a basic input for the production process, the forest resource has been one of the fundamental factors propping up the expansion of China's economy. When China is absorbing imports of timber products in the global market, studies of China's forestry system and its timber market incite greater interest. This paper represents a systematic approach to probe into the comprehensive realities of China's forestry system and its timber market. Econometric methods are applied in analyzing the demand and supply patterns. The empirical analysis is used to forecast the quantity demanded for timber products in China.

Este trabalho teve como objetivo principal contribuir para aprimoramento dos procedimentos de ensaio e da metodologia de medição dos deslocamentos para determinação das deformações específicas de retração das madeiras de Eucalyptus urophylla, E. saligna e do híbrido urograndis nas direções radial e tangencial utilizando o método da Thin-plate Spline - TPS. Foi realizado um estudo teórico e prático de maneira a contribuir para a revisão do texto da Norma Brasileira NBR 7190/97 no sentido de otimizar os ensaios de variação dimensional, principalmente no que se refere à especificação dos corpos-de-prova e ao método utilizado para o cálculo das deformações específicas por retração. Para o desenvolvimento da pesquisa, foram utilizadas 30 árvores das espécies Eucalyptus urophylla, E. saligna, e urograndis provenientes da Estação Experimental de Ciências Florestais de Anhembi, SP. A análise estatística foi feita segundo o delineamento inteiramente casualizado, com amostragem independente e cinco repetições utilizando-se os esquemas fatoriais 3 x 2 x 4 (espécie x altura x posição radial) para o estudo das variáveis obtidas dos corpos de prova em forma de cunha; 3 x 2 (espécie x altura) para o estudo das variáveis obtidas dos corpos-de-prova da NBR 7190/97 e dos discos de umidade; e 3 x 2 x 3 (espécie x altura x método) para o estudo das variáveis obtidas entre os métodos TPScunha, TPS-NBR e NBR. O método proposto mostrou-se sensível às deformações sofridas pelas amostras e possibilita uma análise detalhada das deformações em toda a superfície de um corpode- prova. Foram verificadas variações da retração no sentido medula-casca verificando-se que o método da TPS aplicado no corpo de prova do tipo cunha forneceu valores de retração sempre inferiores aos obtidos através dos procedimentos normatizados. Quando aplicado no corpo cúbico forneceu valores estatisticamente iguais aos obtidos pelo uso da NBR 7190/97. A umidade natural da madeira na árvore viva e a densidade básica da madeira não foram suficientes para explicar as variações encontradas na retração mas verificou-se uma tendência de a retração radial decrescer com o aumento dessas duas variáveis e de a retração tangencial crescer com o aumento da umidade natural e densidade básica. / The present research work had the aim to contribute for the development of testing procedures and evaluation of displacements to determine shrinkage of Eucalyptus urophylla, E. saligna and a hybrid E. urograndis in the radial and tangential directions using the Thin-plate Spline TPS method. It was carried out a theoretical and practical study in order to contribute to reviewing of Brazilian Standard NBR 7190/97 looking forward to optimize the dimensional variation testes mainly on the specification of specimen and method of assessment of shrinkage. Thirty trees of those species from the Forest Sciences Experimental Station of Anhembi were utilized for the study. The statistical analysis were made according full randomly experimental design with independent sampling and five replications through factorial scheme 3 x 2 x 4 (species x longitudinal location x radial location) for the study on variables obtained from the specimens which had the wedge shape; 3 x 2 (species x longitudinal location) for the study on variable obtained from the NBR 7190 standardized specimen and for the study on natural moisture content in trees and 3 x 2 x 3 (species x longitudinal location x method) to compare the methods of assessment of wood shrinkage. The proposed method showed to be sensible to samples shrinkage and make possible a detailed analysis of strains in the whole specimen surface. Shrinkages variations from pith to bark were studied observing that the TPS method applied on the wedge shape specimen produced shrinkage values smaller than those obtained through standardized procedures. When applied on cubic specimen produced values statistically the same as those obtained through NBR 7190/97. The natural moisture content in alive tree and the basic density of wood were not enough to explain the verified shrinkage variation but it was verified a tendency of the radial shrinkage to decrease as those variables increase and a tendency of tangential shrinkage to increase as the natural moisture and basic density also increase.

O objetivo deste estudo foi avaliar a qualidade da madeira para laminação e a divergência genética entre 25 matrizes de Araucaria angustifolia provenientes de um plantio seminal de 39 anos de idade, localizado no município de Palma Sola, SC. Foram avaliadas as seguintes características: silviculturais: altura, diâmetro à altura do peito e volume de madeira com casca e sem casca; morfométricas: conicidade e achatamento e as propriedades físicas: densidade básica no sentido radial e longitudinal, retração linear e volumétrica e o colapso. Foram realizadas análises utilizando a técnica de agrupamento através do método de otimização de Tocher, com uso da dissimilaridade baseada na distância euclidiana, adotando-se, como parâmetro, a dispersão gráfica por meio dos componentes principais e realizando o agrupamento através do Método de Agrupamento de Ligação Médio Entre Grupos (UPGMA). Com base nos resultados observados, os baixos valores de conicidade, achatamento e variação dimensional apresentaram como características favoráveis à produção de lâminas homogêneas, o que qualifica a madeira de A. angustifolia para a produção de painéis laminados. A variação da densidade básica na direção radial e longitudinal apresentaram diferenças estatísticas entre as posições. O estudo da dissimilaridade permitiu a formação de quatro grupos de matrizes. Genótipos destinados à madeira para laminação devem possuir maiores DAP e altura com menores valores de achatamento e de retração tangencial. As matrizes que mais se destacaram com potencial para um programa de melhoramentos foram M1e M21. / The objective of this study was to evaluate the quality of wood for lamination and a genetic divergence among 25 matrices of Araucária angustifólia coming from a seminal planting of 39 years old, located in the municipality of Palma Sola, SC. Were been evaluated the following characteristics: silvicultural: height, diameter at breast height and volume of wood with bark and without bark; Morphometric: conicity and flatness and physical properties: basic density in the radial and longitudinal direction, linear retraction and volumetric and the collapse. Analysis were performed using the grouping technique through Tocher optimization method, use of dissimilarity based on Euclidean distance adopting, as parameter, the graphic dispersion by the main components and performing the grouping Through the Unweighted Pair Group Method using Arithmetic averages (UPGMA). Based on the observed results, the low values of conicity, flattening and dimensional variation presented favorable characteristics for the production of homogeneous sheets that qualifies A. angustifolia wood for the production of laminated panels. The variation of the basic density in the radial and longitudinal direction presented statistical differences between the positions. The study of dissimilarity allowed the formation of four groups of matrices. Genotypes intended for wood for lamination must have higher DBH and height with lower values of flattening and tangential retraction. The most prominent matrices with potential for an improvement program were M1e M21.

Pentachlorophenol (PCP) is a biocide which is widely used for its toxicity to microorganisms. Its major application is in wood preservation, and PCP at abandoned wood preserving sites is a major source of environmental pollution. Although much of the literature documents aerobic treatment for PCP, research indicates that there is great potential for anaerobic dechlorination of these compounds. The objectives of this investigation were to study the acidogenesis phase of the anaerobic biodegradation process; how acidogenesis is affected by PCP toxicity alone and in the presence of zinc; what role acidogenesis plays in the biodegradation of PCP; and how operating parameters, such as organic loading rate (OLR) and solids retention time (SRT) affect the degradation of PCP during acidogenesis. Batch anaerobic toxicity assays (ATAs) were performed to quantify the toxicity threshold for PCP and zinc, and to study the effect of these toxicants on volatile acids production. Continuous reactors (chemostats) were operated at SRTs of 0.25-0.61 day to kinetically exclude methanogenesis from acetate, so that the effects of the toxicants on acidogenesis could be evaluated PCP was found to have a toxicity threshold of 2.7-3.0 mg/L and zinc 23-27 mg/L in batch systems. Acetate utilizers showed the first signs of inhibition in PCP spiked systems, whereas hydrogen utilizers were the first organisms affected in response to a zinc spike. In the continuous systems, PCP in spike concentrations of 7.0 mg/L did not affect the quantity or composition of volatile acids produced in the chemostats. A rise in headspace hydrogen at 30 mg/L zinc indicated that hydrogen utilizers became inhibited in the presence of high zinc concentrations PCP was degraded, with approximately half of the degradation occurring during acidogenesis. GC/MS analysis detected no intermediate chlorophenols in the effluent. The efficiency of degradation varied indirectly with spike concentration and directly with SRT / acase@tulane.edu

This report deals with the fire resistance of cross-laminated timber (CLT). Themain purpose is to verify a new model on CLT and its ability to sustain itsbearing capacity when exposed to fire. To establish this, a series of bendingtestshas been conducted in combination with fire exposure of the CLT. Twodifferent series, with different dimensions, of beams were tested (series 1 andseries 2). Four basic set-ups: CLT in tension or compression, either equippedwith fire protective covering or not. Results from the tests has been gatheredand evaluated to verify the theoretical model of the fire resistance. Evaluationwas made through analysis of the residual cross-sections of the beamsregarding charring depth and rate and moment of inertia (I).Results of the tests verify to a large extent the Design model. Externalproblems and variations in the beams themselves caused some deviations.Analysis confirmed the CLT as being more similar to other laminated productssuch as Laminated Veneer Lumber (LVL) then homogenous solid beams. BothCLT and LVL experience delamination when exposed to fire resulting in anincreased charring rate. The difference in rate when using Gypsum plaster as aprotective barrier against the fire exposure is also equal to LVL.The results of the report will be used in the new version of the EuropeanStandard, Euro Code 5 and in the third edition of Fire Safe Timber Buildings.Charring rates proved to be less than expected but the CLTs ability to withstandfire while keeping its bearing capacity

No description available.

<p>This report deals with the fire resistance of cross-laminated timber (CLT). Themain purpose is to verify a new model on CLT and its ability to sustain itsbearing capacity when exposed to fire. To establish this, a series of bendingtestshas been conducted in combination with fire exposure of the CLT. Twodifferent series, with different dimensions, of beams were tested (series 1 andseries 2). Four basic set-ups: CLT in tension or compression, either equippedwith fire protective covering or not. Results from the tests has been gatheredand evaluated to verify the theoretical model of the fire resistance. Evaluationwas made through analysis of the residual cross-sections of the beamsregarding charring depth and rate and moment of inertia (I).Results of the tests verify to a large extent the Design model. Externalproblems and variations in the beams themselves caused some deviations.Analysis confirmed the CLT as being more similar to other laminated productssuch as Laminated Veneer Lumber (LVL) then homogenous solid beams. BothCLT and LVL experience delamination when exposed to fire resulting in anincreased charring rate. The difference in rate when using Gypsum plaster as aprotective barrier against the fire exposure is also equal to LVL.The results of the report will be used in the new version of the EuropeanStandard, Euro Code 5 and in the third edition of Fire Safe Timber Buildings.Charring rates proved to be less than expected but the CLTs ability to withstandfire while keeping its bearing capacity</p>

Log breakdown by sawing can be viewed as a multi-phase process that converts logs into boards by a series of cutting operations. In the primary phase, logs are sawn into s labs of wood known as flitches or cants. These are further processed by secondary operations, that resaw, edge (cut lengthwise) and trim (cut widthwise) the raw material, resulting in the manufacture of the board product whose value is influenced by its composite dimensions and quality (as indicated by a grade). Board grade is in turn determined by the number, type, size, and location of defects. Owing to its biological origins, each log, and subsequent board, is unique. Furthermore, as each sawmill, and processing centre within the mill, has a unique configuration, the problem of determining how each log entering a mill should be sawn is very complex. Effective computer simulation of log breakdown processes must therefore entail detailed descriptions of both geometry and quality of individual logs. Appropriate strategies at each breakdown phase are also required. In this thesis models for emulating log breakdown are developed in conjunction with an existing sawing simulation system which requires, as input, detailed three-dimensional descriptions of both internal and external log characteristics. Models based on heuristic and enumerative procedures, and those based upon the principles of dynamic programming (DP) are formulated, encoded, and compared. Log breakdown phases are considered both independently and in a combined integrated approach-working backwards from the board product through to the primary log breakdown phase. This approach permits methodology developed for the later processes to be embedded within the primary phase thus permitting the determination of a global rather than local solution to the log breakdown problem whose objective is to seek the highest possible solution quality within the minimum possible time. Simulation results indicate that solution quality and processing speeds are influenced by both solution methodology and degree of data complexity. When the structure of either factor is simplified, solutions are generated more rapidly-but with an accompanying reduction in solution quality. A promising compromise that combines DP techniques with mathematical functions based on a subset of the original data is presented. / Subscription resource available via Digital Dissertations only.