共查询到20条相似文献，搜索用时 578 毫秒
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Tahiana Ramananantoandro Miora F. Ramanakoto Andraina H. Rajemison Florent Eyma 《Annals of Forest Science》2013,70(6):649-658
Context
The knowledge of consumer preferences in wood furniture is crucial for the wood processing industries.Aim
This study aims to identify the attributes of wood that affect the preferences of consumers from the city of Antananarivo, Madagascar, for wooden furnishings.Methods
Quantitative measurements of the density and aesthetic properties of 12 wood species were carried out. The properties measured were the colour in the CIEL*a*b* colour space, the texture through greyscale image processing, and the density. Then, the wood specimens were subjected to sensory analysis with 100 consumers.Results
The results showed that the "density" was a prime criterion in choosing a wood species. Concerning the visual aspect, Antananarivo consumers generally liked slightly dark wood colour (L* around 52), tending towards yellow, with a visible oriented texture. The influence of socio-economic factors was also highlighted.Conclusion
These results are of prime importance in the search for alternative species to replace precious woods that are becoming rare. 相似文献11.
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Shakti S. Chauhan Monika Sharma Jimmy Thomas Luis A. Apiolaza David A. Collings John C. F. Walker 《Annals of Forest Science》2013,70(4):439-449
? Introduction
There has been an increasing interest in very early selection of radiata pine to reduce the breeding cycle for solid wood products. For such selection, new approaches are required to assess wood quality in wood from very young stems.? Methods
Nursery seedlings of clones of radiata pine were grown in leant condition using two leaning strategies for 18–20 months. Opposite wood and compression wood were isolated from the leaning stems and tested for dynamic modulus of elasticity, density, longitudinal shrinkage, volumetric shrinkage and compression wood area using new methods evolved for testing small size samples quickly and reliably. The methods were tested for their efficiency in differentiating clones by their wood properties.? Results
Leaning of stems provided distinct opposite and compression wood for testing. Automated image analysis method used for compression wood area assessment was found to be a quick and effective method for processing large number of samples from young stems. Compression wood was characterised by high basic density, high longitudinal shrinkage and low volumetric shrinkage than that of opposite wood. Acoustic velocity in opposite wood had a strong negative association with longitudinal shrinkage. The study signifies the importance of preventing mixing of opposite wood with compression wood while assessing wood quality in young stems thus making leaning a critical strategy. The comparison of wood properties of opposite wood revealed significant differences between clones. Opposite wood of the clone with the lowest dynamic modulus of elasticity exhibited the highest longitudinal shrinkage.? Conclusion
Significant differences in measurable wood properties between clones suggest the prospects of early selection for solid wood products. 相似文献15.
J. Paul McLean Olivier Arnould Jacques Beauchêne Bruno Clair 《Annals of Forest Science》2012,69(3):399-408
Context and aim
This study aimed to examine the effect of the tension wood G‐layer on the viscoelastic properties of wood.Methods
Tension wood and opposite wood samples were obtained from six French Guianese tropical rainforest species (Sextonia rubra, Ocotea guyanensis, Inga alba, Tachigali melinoni, Iyranthera sagotiana and Virola michelii); the tension wood of the former three of these species had a G‐layer, whilst the tension wood from the latter three had no G‐layer. Tensile dynamic mechanical analysis (DMA) was performed on green never dried wood samples in the longitudinal direction with samples submerged in a water bath at a temperature (30°C) and frequency (1 Hz) representative of the conditions experienced by wood within a living tree. Then, DMA was repeated with samples conditioned to an air-dried state. Finally, samples were oven-dried to measure longitudinal shrinkage.Results
Tension wood did not always have a higher longitudinal storage (elastic) modulus than opposite wood from the same tree regardless of the presence or absence of a G‐layer. For the species containing a G‐layer, tension wood had a higher damping coefficient and experienced a greater longitudinal shrinkage upon drying than opposite wood from the same species. No difference was found in damping coefficients between tension wood and opposite wood for the species that had no G‐layer.Conclusion
It is proposed that the different molecular composition of the G-layer matrix has an influence on the viscoelasticity of wood, even if a biomechanical gain is not yet clear. This study shows that rheological properties and longitudinal shrinkage can be used to detect the presence of a G‐layer in tension wood.16.
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Julie Barrette David Pothier David Auty Alexis Achim Isabelle Duchesne Nancy Gélinas 《Annals of Forest Science》2012,69(5):603-615
Context
To increase the wood supply to its industry, the government of Québec has allocated dead and sound wood (recently dead merchantable stems, DSW) to the wood supply chain in addition to the annual allowable cut of living trees. However, DSW is often criticized by sawmillers for its perceived poor quality and lower value.Aims
The objective of this study was to compare the lumber visual grade yield and value from live and recently dead merchantable trees in three different states of wood decomposition.Methods
In total, 162 black spruce trees [Picea mariana (Mill.) BSP] were felled from three different sites comprising three different states of wood decomposition and three diameter classes. The state of decomposition of each standing tree was categorized following Hunter??s classification (decay stages 1 & 2, 3 and 4) and the DSW classification developed by the Government of Québec.Results
Large trees (> 20?cm) of the Hunter 4 class have a lower value as a result of inferior quality.Conclusion
Considering the current economic difficulties facing the forest industry and the requirements of ecosystem-based management, we recommend leaving in the forest trees that have reached such a state of deterioration. 相似文献19.
Overview of methods and tools for evaluating future woody biomass availability in European countries
Susana Barreiro Mart-Jan Schelhaas Gerald Kändler Clara Antón-Fernández Antoine Colin Jean-Daniel Bontemps Iciar Alberdi Sonia Condés Marius Dumitru Angel Ferezliev Christoph Fischer Patrizia Gasparini Thomas Gschwantner Georg Kindermann Bjarki Kjartansson Pál Kovácsevics Milos Kucera Anders Lundström Gheorghe Marin Gintautas Mozgeris Thomas Nord-Larsen Tuula Packalen John Redmond Sandro Sacchelli Allan Sims Arnór Snorrason Nickola Stoyanov Esther Thürig Per-Erik Wikberg 《Annals of Forest Science》2016,73(4):823-837