Spiral grain in timber may cause severe twisting of lumber and plywood. In the primary forest products industries the presence of spiral grain in the tree results in cross-grained products. Cross grain affects the strength properties of lumber to a marked degree. Thus a grain deviation of 1 In 25 (2°18') results in decreased tensile strength whereas a slope of 1 in 10 (5°43') will reduce compression strength. Spiral grain is a condition well known to the wood technologist and the silviculturalist. Until recently it was considered the exception rather than the rule. From recently published papers, however, and from unpublished data available to the author, strong evidence has been produced to show that spiral grain is the normal growth pattern in trees. This thesis is designed to investigate the spiral pattern of second-growth Douglas fir and western hemlock. Accordingly three sites were chosen: a good, a medium and a low site in a typical British Columbia coastal forest of second growth. Two crown classes for each species were sampled from each site and three trees in each crown class for each species were felled and their spiral patterns investigated. A general trend of spirality was established, the twist being initially left (at first), decreasing to the left and becoming right with increasing age. This pattern holds good for both species. The effect of site on spiral development was established as highly significant with both species. On high quality sites the chief factor influencing spiral development was found to be distance from the pith. On sites of lower quality, age from the pith was found to have the most significant influence on spiral development. / Forestry, Faculty of / Graduate

Orientador: Eduardo Luiz Longui / Banca: Adriano Wagner Ballarin / Banca: Edenise Segala Alves / Resumo: Peltophorum dubium (Spreng.) Taub. é uma espécie nativa considerada promissora por apresentar valor econômico comprovado, em função da qualidade de sua madeira. Esta é empregada em diversos setores da indústria madeireira, da construção civil ao uso na produção de papel e é considerada uma espécie de rápido crescimento, com altos níveis de sobrevivência e acúmulo de biomassa. O objetivo foi estudar o incremento médio anual, as variações nas características anatômicas, propriedades físicas e mecânicas da madeira de P. dubium plantadas em Luis Antônio - SP com sementes de duas procedências (Alvorada do Sul - PR e Bauru - SP). Cortamos 30 árvores com 32 anos, sendo 15 de sementes procedentes de Alvorada do Sul (ASPAS) e as outras 15 com sementes procedentes de Bauru (ASPBA). Retiramos o pranchão central das 30 árvores das toras basais do tronco, desse pranchão retiramos sarrafos com dimensões 3,5x3,5 em três diferentes regiões do raio (PM - próximo à medula, I - intermediário e PC - próximo à casca) e dos sarrafos confeccionamos corpos de prova para caracterização anatômica (macerado e cortes histológicos), propriedades físicas (densidade básica e aparente a 12% de umidade e retração volumétrica) e mecânicas (resistência a compressão paralela às fibras, resistência à flexão, módulo de elasticidade e resistência ao cisalhamento). De acordo com os resultados não há diferença no incremento médio anual entre as procedências. As procedências diferiram apenas na densidade de raios. Fo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Peltophorumdubium (Spreng.) Taub. is a native species considered promising because it presents a proven economic value, due to the quality of its wood. It is used in many sectors of the timber industry, from civil construction to use in paper production and is considered a species of rapid growth, with high levels of survival and accumulation of biomass. The aim of this research was to study the average annual increment, variations in the anatomical characteristics, physical and mechanical properties of P. dubium wood planted in Luiz Antônio - SP with seeds from two sources (Alvorada do Sul - PR and Bauru - SP). We cut 30 trees of 32 years old, where 15 of seeds were from Alvorada do Sul (ASPAS) and the other 15 coming from Bauru (ASPBA). We removed the central board from the 30 trees of the basal logs of the trunk, from this plank we removed 3,5x3,5, dimensions in three different regions of the radius (PM - near the medulla, I - intermediate and PC - close to the bark) and from the battens we made test specimens for anatomical characterization (Basic and apparent density at 12% moisture content and volumetric retraction) and mechanical (resistance to compression parallel to fibers, flexural strength, modulus of elasticity and shear strength). According to the results, there is no difference in the average annual increase among provenances. The provenances differed only in radius density. It was observed an increase in vessel length, vessel diameter, ray width, fiber wall thickness, fiber length, densities, coefficient of anisotropy, modulus of elasticity, resistance to static bending, compression and shear strength, at the medulla-bark direction, and a decrease in vessel density and width and density of rays in the same direction. The wood of the trees with seeds originated from Alvorada do Sul (ASPAS), especially in the region near the bark, is denser and with higher mechanical properties, but it ... / Mestre

The longitudinal air permeabilities of the wood of 1116 specimens from 279 trees, two sapwood and two heartwood replicates, representing two varieties of lodgepole pine (Pinus contorta, vars. latifolia and murrayana) were measured with a steady state apparatus. It was found that the mean ratio of sapwood to heartwood permeability was ca. 10:1 for both varieties. The mean ratio of var. latifolia to murrayana was 1.5:5 and 1.75:5 for sapwood and heartwood, respectively. The most important source of variation following the difference between heartwood and sapwood was that among trees. Geographical locations, such as latitude and elevation did not significantly influence permeability. Tree size did, but only because the small trees (3 inch diameter) showed higher heartwood permeability and lower sapwood permeability than normal. Ca. 20 specimens of latifolia heartwood showed extremely high permeabilities. They were also deeply brown in color, which probably was caused by fungal or bacterial infestation. Pit pore size and number per cm² were determined for sapwood by making four permeability measurements, each at a different average pressure on each specimen. A mean pit pore radius of 1.5 µm and 1.3 µm for sapwood of var. latifolia and var. murrayana was calculated. The median values between 1200-1300 pit pores per cm² indicate an average rate of tracheid connection of 1.2-1.3%. Of the tested wood parameters including moisture content and specific gravity average ringwidth, only the permeability of var. latifolia was significantly correlated with moisture content for both heartwood and sapwood, with a negative correlation coefficient. Water retention measurements were carried out to relate the measured gas permeability of an individual specimen to its ability to absorb water. For both varieties the retention was significantly and quadratically correlated with sapwood permeability (R² = 0.286 and 0.224) and was linearly correlated with heartwood permeability (R² = 0.488 and 0.5775). The correlation factors for the regression between retention and the logarithm of permeability were 0.239 and 0.227 for sapwood and 0.447 and 0.420 for heartwood. / M.S.

With the large number and diversity of materials available today, the ability of the manufacturer to control properties is critical for the success of a product in the market. Although we have little or no control over the engineering properties of solid wood, the potential for the design of material properties in composites is great. Large strides are presently being made in the design of non-veneer structural panels by using material science principles. However, a large gap in our knowledge of the composite system is in the understanding of how raw material properties and processing variables interact to influence the internal geometry and material properties of the components in situ. The ability to use production variables to control material properties of the composite is an extremely valuable tool. The goal of this research is to provide an understanding of how the heat and mass transfer inside a flakeboard during pressing, interacts with the viscoelastic behavior of individual flakes to influence density gradient formation and in situ flake properties. The specific objectives: l. To use observed changes in the temperature and gas pressure of the internal environment of panels during the pressing cycle to describe the composition of the gas phase. 2. To use the calculated composition of the gas phase and measured temperature for the internal environment as boundary conditions for a fundamental heat and mass transfer model to access changes in the temperature and moisture content of the wood component during pressing. 3. To use the temperature and moisture content relations above to qualitatively relate press conditions to the formation of density gradients through changes in the glass transition temperature of the amorphous polymers in wood. 4. To utilize micromechanical models of cellular materials in conjunction with linear viscoelasticity of polymers to develop a nonlinear viscoelasticity model for wood in transverse compression. The approach couples the viscoelastic behavior of the amorphous polymers in wood with the structure imposed by anatomy. These theories, if applicable to wood, can greatly simplify the study of many similar systems combining environmental conditions and mechanical properties. / Ph. D.

The environmental factors affecting wood property formation of Eucalyptus spp. trees in two distinct geographic areas within South Africa were studied. Wood prop~rty data for trees from 43 sites (26 in Zululand and 17 in Mpumalanga) were collected from work conducted at the Forest and Forest Products Research Centre (FFPRC) at the CSIR (Council for Scientific and Industrial Research) in Durban. The wood properties considered included screened pulp yield, fibre length, wood density and active alkali chemical consumption during pulping. The effect of environmental factors on growth rate (expressed as Site Index at a base age of 5 years) was also measured. A detailed site description for each forest compartment was carried out. Detailed annual and monthly rainfall and minimum and maximum temperature estimates were calculated for each site by interpolating long term means of these variables by splining using the software package Anusplin. These estimates of climatic factors were validated by comparison to the data published in the South African Atlas of Agrohydrology and -Climatology. The outputs of the Anusplin model were used to derive surrogate bioclimatic parameters for each site using the computer program Bioclim. These parameters are considered as better descriptors of the energy-water balance experienced by the plant than normal measures of climate such as mean monthly or annual precipitation. Soil characteristics were measured on samples taken from the individual sites. The effects of these environmental and bioclimatic variables on wood properties were analysed using appropriate statistical techniques. Multiple regression models were used to predict wood properties and it is suggested that this approach could form part of a fibre management system. Wood property prediction models incorporating climate (and bioclimate) alone were preferred to those including soil data as no further site data are required. The effect of edaphic factors was considered to describe any further variation not accounted for by bioclimate alone. Particle size distribution of the soil, as an indication of the water holding capacity of that soil, was not found to effect wood properties or growth significantly. A weak influence of organic matter content in the topsoil on wood density was noted in Mpumalanga. In Zululand, a multiple linear regression using both rainfall of the wettest quarter and mean diurnal temperature range as inputs yielded the best predictive model for growth rate. In this region a combination of precipitation seasonality and mean diurnal temperature range gave the best linear regressi'o,n model describing variation in screened pUlp' yield and fibre length. In Mpumalanga effective rooting depth was found to have a pervasive effect on plant development. Solar radiation (as a measure of energy supply), calculated from a function of latitude, aspect, slope and time of year, was also found to significantly affect the growth rate and SPY of plant material in Mpumalanga. Measures of temperature in both geographic regions were found to significantly affect wood density. / Thesis (M.Sc.)-University of Natal, Durban, 2003.

Esta pesquisa tem por objetivo analisar os procedimentos e os resultados de métodos de ensaios propostos para a identificação da resistência ao cisalhamento de madeiras no sentido paralelo as fibras. Almeja-se observar as imperfeições dos métodos existentes, com intuito de propor um novo método de ensaio em que algum dos problemas apresentados possam ser minimizados ou reduzidos. O método proposto pela norma NBR 7190/97 utiliza um corpo de prova prismático retangular com um dente para impedir sua rotação, causada pela assimetria na aplicação da força que promove o cisalhamento. O método proposto por SANTOS NETO (1999) utiliza também um corpo de provas prismático longelíneo com interrupções parciais alternadas nas seções transversais, as quais promovem solicitações de cisalhamento em regiões pré-escolhidas. Como alternativa, o presente estudo apresenta dois métodos: o primeiro método de ensaio sugerido é análogo ao ensaio da norma, porém aplicando a carga simetricamente a duas seções cisalhantes, de modo a evitar a rotação do corpo. Esse método evidenciou problemas ocorridos em razão das proporções entre as tensões de cisalhamento e tensões de esmagamento por compressão na superfície de aplicação das cargas e da antecipação da ruptura de cisalhamento por ruptura de tração na face inferior do corpo de provas. Um segundo procedimento é proposto, induzindo o esforço de cisalhamento através de puncionamento de um corpo de prova prismático simples e sem recortes, com distribuição da seção cisalhantes simetricamente em relação a um ponto. Para tanto, desenvolve-se uma ferramenta de macho e fêmea adaptado a uma prensa universal de ensaios para aplicação dos esforços. Verificada a validade do método, realiza-se um conjunto de ensaios com três espécies de madeiras, diferenciadas entre si pelas suas resistências mecânicas e, valendo-se dos métodos propostos pela norma NBR 7190/97, por SANTOS NETO (1999) e o cisalhamento por puncionamento, analisa-se e discute-se o desempenho dos três processos. / This research aims to examine the procedures and results of test methods proposed for the identification of the shear strength of wood fibers in parallel direction. Aims to observe the imperfections of existing methods, aiming to propose a new test method in which some of the problems shown can be minimized or reduced. The method proposed by NBR 7190/97 uses a rectangular prismatic body of evidence with a tooth to prevent its rotation caused by asymmetry in the application of force that causes the shear. The method proposed by SANTOS NETO (1999) also uses a prismatic body of evidence with alternating partial interruptions in cross sections, which provide requests shear at pre-selected regions. Alternatively, the paper presents two methods: the first test method suggested is analogous to the standard test, but applying the load symmetrically to shear two sections so as to prevent rotation of the body. This method revealed problems that occurred because of the proportions between the shear stresses and strains of crushing by compression on the surface of application of loads and the anticipation of breaking the shear rupture of traction on the underside of the body of evidence. A second procedure is proposed, leading to shear stress by punching a simple prismatic body of evidence and without cutouts, with the distribution of shearing section symmetrical about a point. To this end, it develops a tool of male and female adapted to press a universal test for application of effort. Verified the validity of the method, takes place a series of tests on three wood species, differentiated from each other by their mechanical stregth, and, drawing on the methods proposed by NBR 7190/97, and by SANTOS NETO (1999) and by punching shear, analyzes and discusses the performance of the three cases.

Esta pesquisa tem por objetivo analisar os procedimentos e os resultados de métodos de ensaios propostos para a identificação da resistência ao cisalhamento de madeiras no sentido paralelo as fibras. Almeja-se observar as imperfeições dos métodos existentes, com intuito de propor um novo método de ensaio em que algum dos problemas apresentados possam ser minimizados ou reduzidos. O método proposto pela norma NBR 7190/97 utiliza um corpo de prova prismático retangular com um dente para impedir sua rotação, causada pela assimetria na aplicação da força que promove o cisalhamento. O método proposto por SANTOS NETO (1999) utiliza também um corpo de provas prismático longelíneo com interrupções parciais alternadas nas seções transversais, as quais promovem solicitações de cisalhamento em regiões pré-escolhidas. Como alternativa, o presente estudo apresenta dois métodos: o primeiro método de ensaio sugerido é análogo ao ensaio da norma, porém aplicando a carga simetricamente a duas seções cisalhantes, de modo a evitar a rotação do corpo. Esse método evidenciou problemas ocorridos em razão das proporções entre as tensões de cisalhamento e tensões de esmagamento por compressão na superfície de aplicação das cargas e da antecipação da ruptura de cisalhamento por ruptura de tração na face inferior do corpo de provas. Um segundo procedimento é proposto, induzindo o esforço de cisalhamento através de puncionamento de um corpo de prova prismático simples e sem recortes, com distribuição da seção cisalhantes simetricamente em relação a um ponto. Para tanto, desenvolve-se uma ferramenta de macho e fêmea adaptado a uma prensa universal de ensaios para aplicação dos esforços. Verificada a validade do método, realiza-se um conjunto de ensaios com três espécies de madeiras, diferenciadas entre si pelas suas resistências mecânicas e, valendo-se dos métodos propostos pela norma NBR 7190/97, por SANTOS NETO (1999) e o cisalhamento por puncionamento, analisa-se e discute-se o desempenho dos três processos. / This research aims to examine the procedures and results of test methods proposed for the identification of the shear strength of wood fibers in parallel direction. Aims to observe the imperfections of existing methods, aiming to propose a new test method in which some of the problems shown can be minimized or reduced. The method proposed by NBR 7190/97 uses a rectangular prismatic body of evidence with a tooth to prevent its rotation caused by asymmetry in the application of force that causes the shear. The method proposed by SANTOS NETO (1999) also uses a prismatic body of evidence with alternating partial interruptions in cross sections, which provide requests shear at pre-selected regions. Alternatively, the paper presents two methods: the first test method suggested is analogous to the standard test, but applying the load symmetrically to shear two sections so as to prevent rotation of the body. This method revealed problems that occurred because of the proportions between the shear stresses and strains of crushing by compression on the surface of application of loads and the anticipation of breaking the shear rupture of traction on the underside of the body of evidence. A second procedure is proposed, leading to shear stress by punching a simple prismatic body of evidence and without cutouts, with the distribution of shearing section symmetrical about a point. To this end, it develops a tool of male and female adapted to press a universal test for application of effort. Verified the validity of the method, takes place a series of tests on three wood species, differentiated from each other by their mechanical stregth, and, drawing on the methods proposed by NBR 7190/97, and by SANTOS NETO (1999) and by punching shear, analyzes and discusses the performance of the three cases.

Vom 11. bis zum 13. September 2023 fand die Forstwissenschaftliche Tagung (FowiTa) 2023 in Dresden statt. Die FowiTa findet regelmäßig alle zwei Jahre rotierend an einer der forstlichen Universitäten Deutschlands (Göttingen, Tharandt, Freiburg, München) statt. Sie bietet den im Bereich der Forstwissenschaften Tätigen die Möglichkeit, aktuelle Erkenntnisse aus ihrer Forschung einem breiten forstwissenschaftlichen Publikum vorzustellen. Neben in parallel stattfindenden Sessions organisierten Vorträgen waren Poster-Ausstellungen inkl. Vorstellung der einzelnen Poster und Vorträge von renommierten Keynote-Speakern Teil der FowiTa 2023. Weiterhin bekamen Nachwuchswissenschaftler aus dem Bereich der Forstwissenschaften die Möglichkeit, im Rahmen eigener Sessions ihre Beiträge zur Forschung zu präsentieren. Im vorliegenden Tagungsband sind die Abstracts der gehaltenen Vorträge sowie die ausgestellten Poster aufgeführt.:Programm 10 11. September 2023 14 BEG | Begrüßung 15 K-01 | Keynote - Das Selbst und die Anderen - Waldpolitik zwischen Identitäten und Institutionen (Prof. Dr. Daniela Kleinschmit) 19 K-02 | Keynote - Forestry's Eduring Debt to German Science (Prof. Dr. William Hyde) 21 V-01 | Waldschutz I: Borkenkäfer 23 V-02 | Waldwirtschaft und Klimawandel I: Umwelt, Stress, Mortalität 30 V-03 | Ökologie, Biodiversität, Naturschutz I 39 V-04 | Forstgenetik, Forstpflanzenzüchtung I 46 V-05 | Forstbotanik I 53 V-06 | Waldbau I 61 V-07 | Waldschutz II: Borkenkäfer 69 V-08 | Waldwirtschaft und Klimawandel II: Waldanpassung, Baumartenwahl 77 V-09 | Ökologie, Biodiversität, Naturschutz II 87 V-10 | Forstgenetik, Forstpflanzenzüchtung II 96 V-11 | Eschen-Session 104 V-12 | Waldbau II 116 P 1-3 | Poster Session 126 P-1 | Management mit sozialwissenschaftlichem Schwerpunkt & Sozialwissenschaften 127 P-2 | Naturwissenschaften mit Schwerpunkt Waldschutz 142 P-3 | Naturwissenschaften 1 159 12. September 2023 180 V-13 | Waldschutz III: Krankheiten 181 V-14 | Waldwirtschaft im Klimawandel III: Forest Restoration 187 V-15 | Fernerkundung I 192 V-16 | Forsttechnik, Verfahrenstechnik I 196 V-17 | Forstrecht 201 V-18 | Forstpolitik, Umweltkommunikation I 205 V-19 | Waldschutz IV: Grundsätzliches und Säugetiere 210 V-20 | Waldwirtschaft im Klimawandel IV: Klimaschutz, Kohlenstoffsenke, Wasserhaushalt 215 V-21 | Fernerkundung II 227 V-22 | Forsttechnik, Verfahrenstechnik II 236 V-23 | Holzkunde und Verwendung 245 V-24 | Forstpolitik, Umweltkommunikation II 255 K-03 | Keynote - Über den Wald als chemisches Element (Prof. Dr. Peter Annighöfer) 262 K-04 | Keynote - Verschwommene Grenzen: Zur Handhabung und Wirkung wissenschaftlicher Aussagen in öffentlichen Auseinandersetzungen (Prof. Dr. Senja Post) 264 PV | Preisverleihung Deutscher Forstwissenschaftspreis 266 13. September 2023 267 P 4-6 | Poster Session 268 P-4 | Management mit naturwissenschaftlichem Schwerpunkt 269 P-5 | Naturwissenschaften mit Schwerpunkt Waldbau 287 P-6 | Naturwissenschaften 2 304 V-25 | Waldschutz V: Sturm und Waldbrände 328 V-26 | Bodenkunde I 334 V-27 | Fernerkundung III 341 V-28 | Forsttechnik, Verfahrenstechnik III 351 V-29 | Forstökonomie I: Ökonomik des Kleinprivatwaldes 361 V-30 | Bioökonomie 373 YS-01 | Young Speakers 381 YS-02 | Young Speakers 383 YS-03 | Young Speakers 385 YS-04 | Young Speakers 387 YS-05 | Young Speakers 389 YS-06 | Young Speakers 391 V-31 | Waldschutz VI 392 V-32 | Bodenkunde II 398 V-33 | Fernerkundung IV 404 V-34 | Forsttechnik, Verfahrenstechnik IV 411 V-35 | Forstökonomie II: Landnutzung und Forsteinrichtung 416 V-36 | Wissenschaftskommunikation I 423 V-37 | Agroforstsysteme 429 V-39 | Waldwachstum 435 V-40 | Bioklimatologie und Meteorologie 444 V-41 | Forstökonomie III: Klimawandel und Waldschäden 451 V-42 | Wissenschaftskommunikation II 459 V-43 | Ökologie, Biodiversität, Naturschutz III 466 Register 468 Moderatorenindex 469 Autorenindex 470 Schlagwortindex 479