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John N Saddler - One of the best experts on this subject based on the ideXlab platform.
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fate and influence of western red cedar Extractives in mechanical pulping
Wood Science and Technology, 2000Co-Authors: C I Johansson, Rodger P Beatson, John N SaddlerAbstract:The methanol Extractives from western red cedar mechanical pulps were found to be radically different in composition to the Extractives obtained from the heartwood. The major heartwood extractive components, the tropolones and lignans, were not present in the Extractives from the pulps. However, the proportion of a brown polymer doubled. The low and high molecular weight methanol Extractives components from the pulps were separated using methyl tert-butyl ether. The low molecular fraction contained mostly guaiacyl-based compounds with dihydroquercetin, thujic acid, 3-hydroxy-1-(4′-hydroxy-3′-methoxyphenyl)-2-oxopropane and 4-ethyl-2-methoxy-6-hydroxyphenol being positively identified. The brown polymeric portion had molecular weights ranging from 1,000 to 10,000. Infrared analysis indicated that the polymers were formed from lignans. Examination of the changes in diffuse reflectance UV-visible and infra red spectra of the pulps on extraction with methanol, suggested that the colour resides in insoluble polymers formed from plicatic acid/plicatin during refining.
Jacques Beauchêne - One of the best experts on this subject based on the ideXlab platform.
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Diversity of decay resistance strategies of durable tropical woods species: Bocoa prouacencsis Aublet, Vouacapoua americana Aublet, Inga alba (Sw.) Wild
International Biodeterioration and Biodegradation, 2014Co-Authors: Nadine Amusant, M Nigg, Bernard Thibaut, Jacques BeauchêneAbstract:The study of decay resistance in wood is of interest for wood end-users but also for the global carbon balance since wood biodegradation is a key driver of forest ecosystem functioning through its impacts on carbon and nutrient cycling. We studied the density and wood extractive contents in order to understand decay resistance against soil microflora after 90 days exposure of sapwood and heartwood from three Neotropical wood species known for their decay resistance: Bocoa prouacensis, Vouacapoua americana, Inga alba. Decay resistance was correlated with density more than wood extractive content. The results highlighted different decay resistance strategies. In B. prouacensis, both sapwood and heartwood were highly resistant due to the high density and high content of antifungal wood Extractives. In V. americana heartwood, decay resistance was due to the high synergistic-acting wood extractive content. Conversely, with the least dense wood species I. alba, we found that decay resistance was due to the antifungal wood Extractives synthesized early in the sapwood. In conclusion, we showed that the three wood species with the same level of heartwood decay resistance performance had different decay resistance strategies according to the anatomic and defensive wood traits.
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Radial Variations of Vibrational Properties of Three Tropical Woods
Journal of Wood Science, 2011Co-Authors: Tian Zhang, Bernard Thibaut, Shu-lin Bai, Sandrine Bardet, Tancrède Alméras, Jacques BeauchêneAbstract:Radial trends of vibrational properties, including the specific dynamic modulus (E'/r) and damping coefficient (tand), were investigated for 3 tropical rainforest hardwood species, Simarouba amara, Carapa procera and Symphonia globulifera by free-free flexural vibration test. The microfibril angle (MFA) was estimated through X-Ray diffraction. Consistent patterns of radial variations were observed for all studied properties. E'/r was found to decrease from pith to bark, which is strongly related to the increasing pith-bark trend of MFA. The variation of tand along the radius can be partly explained by MFA, and partly by the gradient of Extractives due to heartwood formation. The coupling effect of MFA and Extractives could be separated through the analysis of log(tand) - log(E'/r) diagram. For the studied species, the extractive content putatively associated to heartwood formation generally tends to decrease the wood damping coefficient. However, this weakening effect of Extractives was not observed for inner part of the heartwood, suggesting the mechanical action of Extractives was reduced during their chemical ageing.
Philippe Gérardin - One of the best experts on this subject based on the ideXlab platform.
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Yield and compositions of bark phenolic Extractives from three commercially significant softwoods show intra- and inter-specific variation
Plant Physiology and Biochemistry, 2020Co-Authors: Maree Brennan, Francis Colin, Stéphane Dumarçay, Clément Fritsch, Sylvain Cosgun, Philippe GérardinAbstract:Tree bark is rich in commercially valuable secondary metabolites such as polyphenolic compounds like flavonoids and tannins. The yield and composition of bark Extractives from Abies alba varies longitudinally within the stem. A. alba bark above the crown had the greatest extractive content, but the concentration of polyphenolic compounds was greatest below the crown. Here, we use a nonlinear model describing how bark extractive yields of A. alba, Picea abies and Pseudotsuga menziesii change with height, where differences among species are accounted for using different model coefficients. For all species there is longitudinal variability in extract yield. For P. abies and P. menziesii, the form of that variation differs depending on whether the bark was located at the same position in the stem as branches. Although the relationship form of total extractive yield differs between branched and un-branched samples, the relationship forms for individual compound yields does not change depending on branch presence. Despite trees from thinned stands having longer crowns and faster growth rates, indicative of greater photosynthetic activity, there was no evidence that thinning had affected either the yield or composition of Extractives in these species. In P. abies, the proportions of flavonoids was higher in bark from the top of the tree, whereas epi-gallocatechin gallate was found in high proportions at the stem base. In P. menziesii bark extracts, taxifolin was the dominant compound, present in significantly higher proportions in bark towards the base of the stem.
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Knot Extractives: a model for analysing the eco-physiological factors that control the within and between-tree variability
Trees, 2017Co-Authors: Zineb Kebbi-benkeder, Bruno Chopard, Rubén Manso, Stéphane Dumarçay, Philippe Gérardin, Francis ColinAbstract:Key messageAbies alba knot extractive concentration increase from tree tip to living crown base and from tight to loose knot parts. The fitted model is proposed for further eco-physiological studies.AbstractThe physiological and ecological mechanisms controlling the knot richness in Extractives require further investigations. We aim to design a model of the vertical distribution of the knot extractive concentrations as a prerequisite for further studies on the eco-physiological studies. At a first attempt, we use this model to test the effect of different competition situations. Fifteen Silver fir trees were sampled according to their social status within three thinning treatments. Discs containing knots were sampled according to their position in reference to the lowest living branch of each tree. Extractions were carried out with hexane and acetone successively. Extractive concentrations in both solvents as well as branch diameters were simultaneously modelled through the seemingly unrelated regression method. For all trees, knot extractive concentrations increase from the tree tip to the living crown base. According to the model, trees with the longest crowns, dominant or/and growing in the thinned stands, exhibited the largest knot extractive concentrations. The model depicted a vertical trend that strongly suggested inducing physiological factors such as protection zone, branch heartwood formation combined with compression wood formation. A strategy was proposed for the quantification of the effect of the ecological factors on the extractive concentrations of knots when these factors act either directly or indirectly via physiological factors. The model is thus an efficient tool to quantify the eco-physiological control on knot Extractives.
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Knot Extractives: a model for analysing the eco-physiological factors that control the within and between-tree variability
Trees-structure and Function, 2017Co-Authors: Zineb Kebbi-benkeder, Bruno Chopard, Rubén Manso, Stéphane Dumarçay, Philippe Gérardin, Francis ColinAbstract:Abies alba knot extractive concentration increase from tree tip to living crown base and from tight to loose knot parts. The fitted model is proposed for further eco-physiological studies. The physiological and ecological mechanisms controlling the knot richness in Extractives require further investigations. We aim to design a model of the vertical distribution of the knot extractive concentrations as a prerequisite for further studies on the eco-physiological studies. At a first attempt, we use this model to test the effect of different competition situations. Fifteen Silver fir trees were sampled according to their social status within three thinning treatments. Discs containing knots were sampled according to their position in reference to the lowest living branch of each tree. Extractions were carried out with hexane and acetone successively. Extractive concentrations in both solvents as well as branch diameters were simultaneously modelled through the seemingly unrelated regression method. For all trees, knot extractive concentrations increase from the tree tip to the living crown base. According to the model, trees with the longest crowns, dominant or/and growing in the thinned stands, exhibited the largest knot extractive concentrations. The model depicted a vertical trend that strongly suggested inducing physiological factors such as protection zone, branch heartwood formation combined with compression wood formation. A strategy was proposed for the quantification of the effect of the ecological factors on the extractive concentrations of knots when these factors act either directly or indirectly via physiological factors. The model is thus an efficient tool to quantify the eco-physiological control on knot Extractives.
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Selected Wood Properties of Prunus Africana (Hook) Grown in Kenya as Possible Reasons for its High Natural Durability
DRVNA INDUSTRIJA, 2013Co-Authors: Francis Mburu, Stéphane Dumarçay, Peter Sirmah, Fred Muisu, Philippe GérardinAbstract:Studies were carried out on the influence of Prunus africana heartwood Extractives on the growth of selected wood decay fungi. Also, wood chemical and mineral content, dimensional stability and anatomical features of P. africana were studied. Heartwood Extractives were tested in 100 ppm and 500 ppm concentrations on white, brown rot, and blue stain fungi and growth inhibition was determined as a factor of time. Dimensional stability was determined by computing the swelling coefficient after the blocks were saturated with moisture. Klason lignin, Kurschner cellulose, extractive and ash contents were determined by standard procedures. Infrared analyses were performed using Perkin Elmer FTIR spectrometer. Microscopic examination was peiformed using an environmental scanning electron microscope. The results showed that the wood is dimensionally stable, and contains 12.7 % Extractives, 37.6 % cellulose and 30.4 % lignin. Extractives deposited in vessels are highly soluble in dichloromethane and mainly composed of terpenes. Extractives were able to inhibit the growth of white rot fungi Coriolus versicolor, brown rot fungi Poria placenta and blue stain fungi Aureobasidium pullulans at different concentrations tested and could explain the high durability of Prunus africana wood species.
C I Johansson - One of the best experts on this subject based on the ideXlab platform.
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fate and influence of western red cedar Extractives in mechanical pulping
Wood Science and Technology, 2000Co-Authors: C I Johansson, Rodger P Beatson, John N SaddlerAbstract:The methanol Extractives from western red cedar mechanical pulps were found to be radically different in composition to the Extractives obtained from the heartwood. The major heartwood extractive components, the tropolones and lignans, were not present in the Extractives from the pulps. However, the proportion of a brown polymer doubled. The low and high molecular weight methanol Extractives components from the pulps were separated using methyl tert-butyl ether. The low molecular fraction contained mostly guaiacyl-based compounds with dihydroquercetin, thujic acid, 3-hydroxy-1-(4′-hydroxy-3′-methoxyphenyl)-2-oxopropane and 4-ethyl-2-methoxy-6-hydroxyphenol being positively identified. The brown polymeric portion had molecular weights ranging from 1,000 to 10,000. Infrared analysis indicated that the polymers were formed from lignans. Examination of the changes in diffuse reflectance UV-visible and infra red spectra of the pulps on extraction with methanol, suggested that the colour resides in insoluble polymers formed from plicatic acid/plicatin during refining.
C. Breuil - One of the best experts on this subject based on the ideXlab platform.
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Gas chromatography–mass spectrometry method for the simultaneous determination of wood extractive compounds in quaking aspen
Journal of Chromatography A, 2001Co-Authors: M.p. Fernandez, P.a. Watson, C. BreuilAbstract:We have developed a rapid gas chromatography-mass spectrometry (GC-MS) method for the detailed compositional analysis of 70 underivatized wood extractive components present in quaking aspen (Populus tremuloides Michx.). Forty-four compounds were unequivocally identified by retention time and mass spectral comparison with standards. An additional 26 chromatographic peaks were assigned to broad chemical classes using retention time and mass spectra features. The results were compared to the respective tert.-butyldimethylsilyl derivatized wood Extractives profile, and it was determined that derivatization was unnecessary for the GC-MS analysis of the target compounds.
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Gas chromatography-mass spectrometry method for the simultaneous determination of wood extractive compounds in quaking aspen.
Journal of Chromatography A, 2001Co-Authors: M.p. Fernandez, P.a. Watson, C. BreuilAbstract:We have developed a rapid gas chromatography-mass spectrometry (GC-MS) method for the detailed compositional analysis of 70 underivatized wood extractive components present in quaking aspen (Populus tremuloides Michx.). Forty-four compounds were unequivocally identified by retention time and mass spectral comparison with standards. An additional 26 chromatographic peaks were assigned to broad chemical classes using retention time and mass spectra features. The results were compared to the respective tert.-butyldimethylsilyl derivatized wood Extractives profile, and it was determined that derivatization was unnecessary for the GC-MS analysis of the target compounds.
