Thesis (Ph. D.)--University of Canterbury, 2005. / Typescript (photocopy). Includes bibliographical references (leaves 207-214). Also available via the World Wide Web.

O presente trabalho tem como objetivo o uso de modelos os para melhorar o controle do processo de secagem de madeira serrada, tomando como base a Lei de Fourier para modelar o fluxo de calor e a 2a Lei de Fick para o fluxo de massa. Para a avaliação do modelo de Fourier Coram utilizadas tábuas de Pinus taeda L. de 46mm de espessura, submetidas às temperaturas de bulbo seco de 40°C, 60°C e 80°C e velocidades do ar de 3,5, 4,7 e 6,8 m/s. Em todos os ensaios a umidade relativa foi mantida em 100%. No caso da aplicação da 2a Lei de Fick Coram utilizadas tábuas de Pinus elliottii Engelm de 36mm de espessura, submetidas as mesmas temperaturas, no entanto com uma velocidade do ar de 3,0m/s e uma umidade relativa de 40%. Os resultados dos ensaios indicaram que a relação de Chilton-Colburn permite determinar os coeficientes convectivos de calor e massa. O coeficiente convectivo de calor pode ser determinado do número de Nusselt, considerando um fluxo ao longo de um duto de seção retangular baseado no diâmetro hidráulico. O coeficiente de difusão aumentou com a temperatura e diminuiu com o teor de umidade da madeira. A solução do modelo de Fourier representou melhor o comportamento experimental dos dados quando o valor de Biot tendendo ao infinito e considerado. Isto indica que a resistência à transferência de calor do material e bem superior que a convecção de calor do fluido na superfície. Com base nos resultados obtidos concluiu-se, que o modelo de Fourier permite estimar com boa precisão a temperatura no centro da madeira e que o modelo difusivo, baseado na segunda Lei de Fick, permite predizer os gradientes de umidade e a taxa de perda de umidade, durante o processo de secagem. Os resultados também indicam que a gradiente de umidade das peças gerado pelo modelo pode ser utilizado na prática para ajustar o processo de secagem de madeira serrada e, com base nisto, mitigar rachaduras superficiais. Este aspecto em particular pocle ser explorado em mais detalhes em estudos futuros

Orientador: Sidon Klinert Junior / Tese (doutorado)-Universidade Federal do Parana, Setor de Ciencias Agrarias, Programa de Pós- Graduação em Engenharia Florestal / Área de concentração: Tecnologia e utilização de produtos florestais / O presente trabalho teve por objetivo a determinação das propriedades elásticas e de resistência das chapas de madeira compensada confeccionadas com Pirnis taeda L. e Pinus elliottii Engeim., provenientes de plantios com 30 anos de idade, localizados na Floresta Nacional de Irati Estado do Paraná. Foi estudada a variabilidade da massa específica e das propriedades mecânicas de flexão estática no sentido medula-casca no tronco da árvore, lâminas e compensados. Procurou-se determinar modelos para estimar as propriedades dos compensados e correlacionar o efeito das características da madeira nas propriedades. Foram realizados cálculos teóricos para estimar as propriedades de resistência e rigidez dos compensados a partir de propriedades de resistência da madeira e lâminas. Os resultados obtidos para as propriedades mecânicas e massa específica da madeira, lâminas e compensados mostraram diferenças significativas no sentido medula-casca no tronco, para ambas as espécies. A massa específica mostrou uma alta correlação com as propriedades mecânicas da madeira e lâminas e baixa correlação com as propriedades mecânicas dos compensados. A massa especifica e as propriedades mecânicas da madeira não mostraram ser um estimador aceitável das propriedades mecânicas e massa específica dos compensados. Os resultados dos cálculos teóricos do módulo de ruptura (MOR) e o módulo de elasticidade (MOE) nas direções principais (x e y), dos compensados, tiveram uma forte equivalência aos valores observados através de ensaios convencionais, As propriedades de resistência mecânica de flexão estática e compressão paralela da madeira, em termos de módulo elasticidade longitudinal (EL) e tangencial (ET), utilizadas nas equações teóricas de predição. foram os de melhor desempenho. Os valores estimados para o MOE variaram de 8 a 160/o no sentido paralelo e de 1 a 7% no sentido perpendicular, em relação ao valores observados, para o MOR de 1 a 6% para as duas direções principais, em ambas as espécies. As propriedades mecânicas dos compensados estimadas teoricamente, considerando atuantes somente as lâminas sob tensão paralelas ao vão, variaram de 1 a 10%, em relação aos cálculos. considerando toda a seção transversal. / The objetive of this work was to determine the elastic constants and strenght properties of plywood manufactured, from a 30 year-old Pinus taeda L. and Pinus elliottii Engeim., plantation from Iratí National Forest, Paraná State. The variability of specific gravity and mechanical properties in static bending from pith to bark of the bole, venner and plywood was studied. Models to stimate the properties of plywood and to correlate the effect of wood characteristics in properties were created. Theoric calculations were made in order to stimate plywood rigidity and strenght properties with venner and wood strenght properties. Results obtained from mechanical properties and specific gravity m plywood, veneer and wood showed significant difference from pith to bark wood of the bole for both species. The specific gravity of wood presented a high correlation with venner and wood mechanical properties, and 10w correlation with plywood mechanical properties. The specific gravity and wood mechanical properties did not prove to be an acceptable estimator of mechanical properties and plywood specific gravity. The results of theoric calculations of modulus of rupture (MOR) and modulus of elasticity of plywood (MOE) m the two principal directions (x and y) had a strong equivalence with the values observed through conventional tests. The modulus of parailel elasticity in static bending (EL) and perpendicular compression (ET) of wood, to calculate the theorics values. were the best to expiam the values obtained in relation to the observed values, The estimate MOE in piywood varied from 8 to 16% on paraliel direction and from 1 to 7% on perpendicular direction. The variation MOR was from 1 to 6%, in the two principal directions in both species. The theoric estimate mechanical properties of plywood, considering oniv the paraliel venner of span. varied from 1 to 10% m relation to the value obtained using ali transversal section,

Abstract It has been suggested that pine needles protect themselves against UV-B radiation via anatomical and chemical changes in the epidermal layer. This could lead to growth reductions if more assimilates are allocated to the protection mechanisms in the epidermis at the expense of the photosynthetic area. If the protection is insufficient, the UV-B radiation could cause oxidative stress. Moreover, the UV-B-induced stress could increase year by year and the responses could become cumulative. Therefore, two different UV-B field experiments were conducted at two sites. The first was a long-term experiment on mature, naturally growing Scots pines (Pinus sylvestris L.) in Oulu (65°N), Finland, during the growing seasons 1996–1998 (25% ozone depletion) and the second one was a one-growing-season experiment on Scots pine and loblolly pine (Pinus taeda L.) seedlings in Maryland (39°N), USA, in 1997 (16% and 25% ozone depletion scenarios). In Scots pine seedlings, UV-B treatments decreased the primary needle length at the early stages, but no significant differences were seen in fully-grown needles. In mature Scots pines, the response was opposite and UV-B accelerated needle growth in young needles. This suggests that at the early stage of development, the primary needles of seedlings are more sensitive than the fascicle needles of adult pines. Thus, the developmental stage of the studied organisms must be taken into account. Scots pine seedlings protected themselves against UV-B by increasing the thickness of the cutin layer and the epidermal wall (outer and periclinal walls and anticlinal wall), which features have been connected to xeromorphic structure, and by reducing significantly the cross-sectional, mesophyll and epidermal areas. In mature Scots pines, similar trends towards smaller cross-sectional and mesophyll areas and significantly reduced epidermal + hypodermal area were seen in fully-grown UV-B-treated needles. Loblolly pine responded to supplemental UV-B by producing more phenolic compounds into epidermal cell walls and epidermal lumen, which could have resulted in thicker outer epidermal walls. In both of the studied species, these protection mechanisms were sufficient to prevent growth reductions in fully-grown current-year needles. This demonstrates the difference between the studied species and shows that no general interpretations can be made on the effects of UV-B radiation on conifers. The cumulative effects of UV-B radiation were studied from current-year and current+2-year old needles of mature Scots pines during the third UV-B exposure season. The UV-B stress was observed in the current+2-year old needles of mature Scots pines as a degradation of total glutathione, GSHtot, and a bigger proportion of oxidized glutathione, GSSG%, in July during the third UV-B exposure season. In current-year needles, no increase in GSSG% was seen in either the first or the third season. After the third experimental season in September, the GSHtot levels decreased in UV-B-treated current-year needles. These results suggest that the effect of UV-B is duration-dependent and cumulative. The longevity of mature Scots pine needles at the study site is four to five years, and the effects of UV-B should thus be studied over the whole life span of a needle.

Soil borne fungi isolated from forest areas and nurseries in North east of Scotland using baiting techniques, were identified using classical taxonomy and molecular methods (PCR amplification of ITS regions; restriction digestion; sequencing of PCR products) as Fusarium lateritium, F. tricinctum, F. sambucinum, Phytophthora cinnamomi, Pythium ultimum var. ultimum and Rhizoctonia binucleate (Ceratobasidium sp.). Virulence was tested in vitro on young seedlings of Pinus sylvestris and Alnus glutinosa, and Koch's postulates fulfilled through reisolation of the pathogens and confirmation of fungal penetration into host tissues. Root growth was measured using the Winrhizo program, and dry weights recorded. Symptoms on aerial parts were assessed using a categorical scale from 0 (healthy) to 5 (damage > 76%). Fusarium spp. caused significant different (P 0.01) symptom intensity on both host plants. However, no significant difference in root growth was found between treatments and control (P 0.05). The effects of different compost treatments on disease development in seedlings of both hosts inoculated with the same fine root pathogens was tested in the glasshouse confirming the virulence of the fungal pathogens on P. sylvestris and A. glutinosa seedlings. Although mean dry weights of P. sylvestris and A. glutinosa varied between compost treatments, differences were not significantly different. Isolation, characterization and identification of bacterial isolates, Bacillus subtilis B1, fluorescent pseudomonads B4 and B5 with antagonistic action against pathogens were also carried out. These isolates along with the known bacterial antagonists Bacillus subtilis MB600, MB205 and Pseudomonas corrugata R117 were used for biological control in vitro and in planta experiments using Alnus glutinosa or Pinus sylvestris seedlings. All bacterial isolates colonized root systems of both tree species. Higher numbers of bacterial cells were observed on roots of A. glutinosa than on P. sylvestris roots. High bacterial cell numbers were observed in plants of both tree species inoculated with fluorescent pseudomonads B4 or B5. In vitro antagonism on agar plates, indicated by inhibition in fungal colony diameter growth, was recorded for F. tricinctum, F. lateritium and F. sambucinum, Pythium ultimum var. ultimum and Phythophthora cinnamomi with all bacterial isolates tested (P 0.05). Biological control of the fine root pathogens on Pinus sylvestris and Alnus glutinosa seedlings by bacteria semi in vivo in test tubes was carried out with various responses in both tree hosts. All bacterial treatments resulted in a lower sporangium germination rate for P. ultimum var. ultimum than was found in controls (P 0.05). Effect of the bacterial isolates separately on growth and disease development in Pinus sylvestris and Alnus glutinosa seedlings inoculated with the pathogens under glasshouse conditions using autoclaved compost was tested. The bacterial isolates had various effects against the pathogens, although in most cases no significant differences were observed relative to controls. Further soil-based trials were carried out in the glasshouse to achieve control of root disease development on Pinus sylvestris and Alnus glutinosa using a combination of different antagonists, based on a mixture of the bacterial isolates used previously and Trichoderma koningii (TC6-Colombia). None of the antagonistic treatments showed a clear antagonistic effect in Pinus sylvestris against the fungal infections compared to control plants inoculated with the pathogens alone. In contrast, in Alnus glutinosa plants T. koningii co-inoculation improved plant growth in several of the growth parameter measured.

No description available.

The ontogeny of vascular cambium and the wood formation in the 8 month-old Pinus radiata have been examined. The results showed that the procambium develops from the subapical meristem parenchyma, which is converted to pro cambial cells by periclinal division about 0.5 mm from the shoot tip. The interfascicular cambium originates from the interfascicular parenchyma, which is also derived from the subapical meristem. Transverse sections show that the interfascicular parenchyma convert to interfascicular cambial cells requires activation by the fascicular cambium. The vascular cambium was established by the fascicular cambium connecting with the interfascicular cambium. Compression wood formation is related to the plantlet's response to stress. The magnitude and distribution of compression wood is related to whether the stem is free-growing, staked vertically, or tied to an inclined stake, the three situations generating 27%, 14% and 49% compression wood as assessed by image analysis of thin sections. Stiffness, density, tracheid length, cell numbers/mm2, and percent cell wall area were tested for plantlets of clones 8 and 31 grown under three treatments. Compared to the free grown plantlets, the angled plantlets were shorter, thinner, contained more compression wood with thicker cell walls and more cells/mm2, and had shorter denser tracheids to formed weaker wood. By contrast the tied plantlets were taller and thinner, having fewer cells/mm2 with each tracheid being longer and less dense (thinner cell walls), but of similar stiffness to the free grown ones. Compression wood was stiffer than opposite wood because of its higher density, and the angled plantlets were weaker than the free and tied plantlets due to their shorter tracheids. Stiffness is related to density in angled plantlets, and related to tracheid length in the free and tied plantlets. Tracheid length is negatively related to density, cells/mm2, and percent cell wall. Density is related to percent cell wall and cells/mm2, and the percent cell wall and cells/mm2 related each other. Stiffness, microfibril angle, density, and maximum crushing strength have been studied for 1 and 2 year-old seedlings from seedlots 10 and 28. The results indicated that stiffness increased and microfibril angle decreased from one year-old to two year-old material. A relationship between maximum crushing strength and density and a negative relationship between stiffness and microfibril angle existed in two years old plantlets. Stiffness and maximum crushing strength related each other in both one and two years old plantlets. Overall, this work proved to be a scoping trial. While the results could have been anticipated in general terms they do provide a useful description of very young wood. The extent of compression wood varied greatly between treatments, but even in the best case (tied) it takes up a significant proportion of the stem cross-section. However, the technical challenges, especially in the measurement of mechanical properties in such small samples remains a formidable challenge.

Although the peak diversity of Pinaceae is reflected by many Cretaceous seed cones representing extinct genera, the oldest definitive record of the family is attributable to an extant genus. A seed cone discovered at the Valanginian Apple Bay locality extends the record of Picea by ~75 Ma, resolving a ghost lineage predicted by molecular dating analyses. However, a pine from the Eocene Princeton Chert indicates that extant genera are themselves relicts of greater historical diversity. Pinus arnoldii Miller is reconstructed here as the first organismal concept for an extinct member of Pinaceae, on the basis of anatomical attachments between the seed cones attributable to Subgenus Pinus, and vegetation like that of Subgenus Strobus. The phylogenetic implications of these fossils are assessed through cladistic analyses, and comparisons with maximum likelihood ancestral states reconstructed on topologies derived from Bayesian cpDNA analysis of extant Pinus and Picea. / in Systematics & Evolution

Thesis (M.Ag.Sc.) University of Adelaide, Dept. of Plant Pathology, 1978.

Thesis (Ph. D.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (leaves 192-222). Also available via the World Wide Web.