Search

Abstract Background Taxonomic identification of wood specimens provides vital information for a wide variety of academic (e.g. paleoecology, cultural heritage studies) and commercial (e.g. wood trade) purposes. It is generally accomplished through the observation of key anatomical features. Classic methodologies mostly require destructive sub-sampling, which is not always acceptable. X-ray computed micro-tomography (µCT) is a promising non-destructive alternative since it allows a detailed non-invasive visualization of the internal wood structure. There is, however, no standardized approach that determines the required resolution for proper wood identification using X-ray µCT. Here we compared X-ray µCT scans of 17 African wood species at four resolutions (1 µm, 3 µm, 8 µm and 15 µm). The species were selected from the Xylarium of the Royal Museum for Central Africa, Belgium, and represent a wide variety of wood-anatomical features. Results For each resolution, we determined which standardized anatomical features can be distinguished or measured, using the anatomical descriptions and microscopic photographs on the Inside Wood Online Database as a reference. We show that small-scale features (e.g. pits and fibres) can be best distinguished at high resolution (especially 1 µm voxel size). In contrast, large-scale features (e.g. vessel porosity or arrangement) can be best observed at low resolution due to a larger field of view. Intermediate resolutions are optimal (especially 3 µm voxel size), allowing recognition of most small- and large-scale features. While the potential for wood identification is thus highest at 3 µm, the scans at 1 µm and 8 µm were successful in more than half of the studied cases, and even the 15 µm resolution showed a high potential for 40% of the samples. Conclusions The results show the potential of X-ray µCT for non-destructive wood identification. Each of the four studied resolutions proved to contain information on the anatomical features and has the potential to lead to an identification. The dataset of 17 scanned species is made available online and serves as the first step towards a reference database of scanned wood species, facilitating and encouraging more systematic use of X-ray µCT for the identification of wood species.

Background: Taxonomic identification of wood specimens provides vital information for a wide variety of academic (e.g. paleoecology, cultural heritage studies) and commercial (e.g. wood trade) purposes. It is generally accomplished through the observation of key anatomical features. Classic methodologies mostly require destructive sub-sampling, which is not always acceptable. X-ray computed micro-tomography (µCT) is a promising non-destructive alternative since it allows a detailed non-invasive visualization of the internal wood structure. There is, however, no standardized approach that determines the required resolution for proper wood identification using X-ray µCT. Here we compared X-ray µCT scans of 17 African wood species at four resolutions (1 µm, 3 µm, 8 µm and 15 µm). The species were selected from the Xylarium of the Royal Museum for Central Africa, Belgium, and represent a wide variety of wood-anatomical features. Results: For each resolution, we determined which standardized anatomical features can be distinguished or measured, using the anatomical descriptions and microscopic photographs on the Inside Wood Online Database as a reference. We show that small-scale features (e.g. pits and fibres) can be best distinguished at high resolution (especially 1 µm voxel size). In contrast, large-scale features (e.g. vessel porosity or arrangement) can be best observed at low resolution due to a larger field of view. Intermediate resolutions are optimal (especially 3 µm voxel size), allowing recognition of most small- and large-scale features. While the potential for wood identification is thus highest at 3 µm, the scans at 1 µm and 8 µm were successful in more than half of the studied cases, and even the 15 µm resolution showed a high potential for 40% of the samples. Conclusions: The results show the potential of X-ray µCT for non-destructive wood identification. Each of the four studied resolutions proved to contain information on the anatomical features and has the potential to lead to an identification. The dataset of 17 scanned species is made available online and serves as the first step towards a reference database of scanned wood species, facilitating and encouraging more systematic use of X-ray µCT for the identification of wood species. [ABSTRACT FROM AUTHOR]

ABSTRACT Brazil stands out as one of the largest manufacturers of MDF (medium density fiberboard) in the world. The industries are concentrated in the south and southeast of the country and are primarily based on the use of Pinus and Eucalyptus wood, which are available in extensive planted areas. In the northern region, there is only one MDF industrial plant. Despite an abundance of potential raw materials in this region, there is a lack of studies on native species wood and their industrial waste utilization for MDF production. The present study aimed to evaluate the properties of MDF manufactured from a mixture of cultivated paricá (Schizolobium amazonicum) wood and wood waste from native Amazonian species. The study assessed the isolated effects of different proportions of the raw materials and panel thicknesses on MDF properties. Panels were produced, and samples were obtained for testing. Using standard procedures, the following properties were determined: density, water absorption, thickness swelling, internal bonding, static bending, and resistance to screw withdrawal. The results revealed a significant impact of the analyzed variables on some physical and mechanical properties of MDF. With the exception of internal bonding, all other properties of the evaluated MDF panels met the specified regulatory requirements for use in furniture manufacturing. It is concluded that mixtures of the assessed raw materials have great potential for MDF production in the furniture industry. However, adjustments in the production process are recommended to improve the internal bonding property.

The collection of wood samples is an important step, especially for the identification of wood in cultural heritage. Furthermore, in wood sampling, it is preferable to avoid any damage to minimize destruction to the objects. This study aimed to observe the effectiveness of the minimally invasive sampling method using a hollow punch for wood identification on wooden cultural heritage, such as the Panji mask (Java). The materials used as a testing model were three tropical wood species. Sampling was conducted with various diameters of hollow punch at transverse, tangential, and radial sections. The anatomical structures were compared to the features according to the IAWA list of microscopic features for hardwood identification. The result showed that the most effective method was to take samples using a 1.5 mm diameter of hollow punch at the tangential section of wood.

Copyright of Ge-Conservación is the property of Instituto del Patrimonio Cultural and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Thermal modification is an environment-friendly technology for improving various wood properties, especially the dimensional stability, decay resistance, and color homogeneity. In this work, four tropical wood species (African padauk, merbau, mahogany, and iroko) were thermally modified by the ThermoWood process. The influence of heat treatment on the color and chemical changes of wood was studied by spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, and wet chemistry methods. As the temperature increased, a decrease in lightness (L*) and a simultaneous decrease in chromatic values (a*, b*) were observed, indicating darkening and browning of the wood surface. As a result of the heat treatment, the relative content of hemicelluloses decreased the most in merbau and mahogany, while the thermal stability of iroko and African padauk was higher. All examined wood species showed a strong correlation between the lightness difference value (ΔL*) and the content of hemicelluloses (r = 0.88–0.96). The FTIR spectroscopy showed that the breakdown of C═O and C═C bonds in hemicelluloses and lignin plays an important role in the formation of chromophoric structures responsible for the color changes in the wood.

This paper deals with an innovative experimental study performed on glued-laminated timber (GLT) beams, machined and made with three tropical hardwood species. Defect-free beams were obtained by combining alternatively the lamellas taken from the densest to the least dense species, to have TRIO and DUO specimens. Then, static 3-point bending tests were performed on these beams, to assess their mechanical properties and their reliability. Finally, the shear strength tests of the various glue joints are done to understand the failure mode of the beams observed during the bending tests and their impact on the mechanical behaviour of the GLT beams tested. The results show for the two types of GLT (DUO and TRIO's beams) studied here that: (i) comparatively to the combinations of two lamellas (DUO's beams), by taking into account the solid woods and homogeneous beams as references, beams with three lamella combinations (TRIO's beams) present the best mechanical characteristics; (ii) There is a significant influence of the individual lamella's position or the type of lamella on the global behaviour of the GLT's beams. Moreover, the advantages of this type of timber beam material are investigated and shown herein. [ABSTRACT FROM AUTHOR]

ABSTRACT Wood has been used for several purposes such as in civil and rural construction. Knowing wood mechanical behavior under short-term loading is essential for safer structural designs. However, wood toughness is a mechanical property little investigated for this purpose. Thus, this study aimed to evaluate, using exponential and polynomial regression models (linear, quadratic, and cubic), the possibility of estimating toughness as a function of apparent density, compression parallel to grain strength, and modulus of rupture in static bending. Thirty-six Brazilian tropical wood species from south of Roraima, Mato Grosso do Sul, and north and northeast of Mato Grosso were tested. Our results showed the significance and representativeness of all investigated fits, among which a cubic polynomial function is the most indicated for wood toughness estimates.

The “Selva Central” of Peru is characterized by its forest species richness that produces quality wood for countless uses. Therefore, it is necessary to identify the wood and its macroscopic anatomy, which is an important tool for the botanical identification of tree species. For this purpose, 13 sawmills located in 3 provinces were selected that exploit several tree species of “Selva Central”. Sampling of representative woods was carried out, identified by common names and, in the laboratory, they were polished, examined, and grouped by the similarity of the macroscopic anatomical structure, leading to the tree species identification. Twenty tree species were identified, belonging to 17 genera, with emphasis on the Lauraceae and Fabaceae families. However, Moraceae, Meliaceae, Lecythidaceae, Euphorbiaceae, Bignoniaceae, Myristicaceae, Combretaceae, and Burseraceae families were also identified. The anatomical structures of all the identified tree species were described, transversal and longitudinal tangential cross section images were collected, and a species identification key was constructed. The implications and importance of tree species identification via wood anatomy were discussed, in terms of controlling forest exploitation, traceability of the production chain, and the future development of an artificial intelligence tree-species identification method. [ABSTRACT FROM AUTHOR]

This study aimed to assess the natural durability of 20 Amazonian wood species preserved with chromated copper arsenate (CCA) after 30 years in ground contact in an experimental field test at National Forest of Tapajós, Pará state - Brazil. Heartwood samples with a cross-section of 5 × 5 cm and 50 cm of length were half-buried in soil and inspected every year for decay. The species were classified according to natural durability following the classification method proposed by Findlay (Findlay, W.P.K. (1985). The nature and durability of wood. In: Findlay, W.P.K. (Ed.), Preservation of timber in the tropics. Springer Science, Whitchurch, pp. 1–13). After 30 years in ground test, six species were classified as Perishable, seven as Non-durable, three as Durable and four as Very durable, namely: Trichilia lecointei, Lecythis pisonis, Pseudopiptadenia suaveolens, and Dipteryx odorata (Very durable), Protium tenuifolium, Dinizia excelsa, and Ormosia paraensis (Durable), Endopleura uchi, Goupia glabra, Pouteria egregia, Tachigali chrysophylla, Tachigali paraensis, Vatairea sericea, and Vochysia maxima (Non-durable) and Chrysophyllum lucentifolium, Couratari oblongifolia, Didymopanax morototoni, Lueheopsis duckeana, Sterculia excelsa, and Xylopia nitida (Perishable). CCA preservative treatment was effective to promote timber protection, even under harsh climatic conditions of the Amazon forest environment. [ABSTRACT FROM AUTHOR]

Wood identification of barbecue charcoal from commercial packages of three retailers (B1, B2, B3) in Slovenia and Croatia was performed with help of Confocal Laser Scanning Microscopy (CLSM). CLSM enabled us to image key identification features of charcoal wood that were compared with light micrographs of wood from the reference collection. Product B1 contained charcoal made exclusively of beech wood (Fagus sylvatica) and the declaration indicated the address of the producer, in Serbia which allowed traceability of the wood. The selection of wood species in product B2, consisted of red oak (Quercus cerris or Q. rubra), black locust (Robinia pseudoacacia), and cherry (Prunus avium), which could originate from Serbia, and it did not contain tropical wood as stated on the package. Product B3 contained wood from at least four (sub)topical species which could not be exactly identified to species/genus level. The declaration on the product did not allow traceability of wood. As the risks of illegal logging are high for wood of (sub)tropical origin, our results support the initiative that the monitoring of the charcoal trade should be covered by the EUTR - European Timber Regulations.

Acoustic properties such as specific dynamic Young’s modulus (Ed/γ), internal friction (Q-1), and acoustic conversion efficiency (ACE) of wood are important properties frequently examined using free-free flexural vibration. This study determined the suitability for making musical instrument soundboards and frameboards from four tropical wood species; namely Syzygium, Dialium, Gymnostoma, and Sindora. The results show that (Ed/γ), (Q-1), and ACE were in the range of 20.0 to 28.9 GPa, 0.0031 to 0.0085, and 3.41×107 to 10.83×107, respectively. Based on the results, Syzygium was preferred for making the frameboard of violins and guitars. The outer sapwood (outer part) of Syzygium was the most suitable for making frameboard by considering the lowest ACE and highest Q-1. Based on Ed/γ, the inner sapwood (middle part) in Dialium was the most suitable for making soundboard, but based on Q-1 and ACE, heartwood (inner part) was the most preferred for making soundboard. Gymnostoma was also preferred for making soundboard of violins and guitars (inner sapwood) because it yields the highest mean value of Q-1 and ACE. Considering ACE and Q-1, the outer sapwood in Sindora was the best for making frameboard. When considering Ed/γ and Q-1, the heartwood is the most suitable for making the frameboard of violins and guitars.

This paper presents the research work undertaken to study the properties of Wood Cement Composite Bricks (WCCB) from different wood wastes and cement / wood content. The WCBBs with nominal density of 1200 kg m-3 were produced from three tropical wood species and at varying cement and wood content of 2:1, 2.5:1 and 3:1 on a weight to weight basis. The properties evaluated were compressive strength, Ultra Pulse Velocity (UPV), water absorption (WA) and thickness swelling (TS). The Compressive strength values ranged from 0.25 to 1.13 N mm-2 and UPV values ranged from 18753 to 49992 m s-1. The mean values of WA after 672 hours (28 days) of water soaking of the WCCBs ranged from 9.50% to 47.13% where there were no noticeable change in the TS of the bricks. The observed density (OD) ranged from 627 to 1159 kg m-3. A. zygia from the three wood/cement content were more dimensionally stable and better in compressive strength than the other two species where T. scleroxylon had the best performance in terms of UPV. All the properties improved with increasing cement content. WCCBs at 3.0:1 cement/wood content are suitable for structural application such as panelling, ceiling and partitioning

The acoustical properties of four Indonesian tropical hardwood species were evaluated in this study. The objectives of this study were to determine acoustical parameters e.g. logarithmic decrement, sound absorption, sound velocity as well as density and wood stiffness; and to evaluate the potential of those species for acoustical purposes. Sonokeling (Dalbergia latifolia), Mahoni (Swietenia mahagony), Acacia (Acacia mangium) and Manii wood (Maesopsis eminii) were selected in this research. Three different cutting plane patterns of sawn timber (quarter-sawn, flat-sawn, and plain-sawn) were converted into small specimens. The methods for determining acoustical properties were longitudinal vibration testing and time of flight of ultrasonic wave method. The result showed no significant difference (α=0.05) of acoustical properties in logarithmic decrement, sound absorption, and ultrasonic velocity means on quarter-sawn, flat-sawn, and plain-sawn for all wood species tested. We found that Mahoni and Sonokeling had good acoustical properties of logarithmic decrement, ultrasonic wave velocity, and ratio of wood stiffness to wood density; and is preferred for crafting musical instruments. Acacia and Manii woods are recommended for developing acoustic panels in building construction because those species possess higher sound absorption values.

Acoustic properties such as specific dynamic Young's modulus (Ed/γ), internal friction (Q-1), and acoustic conversion efficiency (ACE) of wood are important properties frequently examined using free-free flexural vibration. This study determined the suitability for making musical instrument soundboards and frameboards from four tropical wood species; namely Syzygium, Dialium, Gymnostoma, and Sindora. The results show that (Ed/γ), (Q-1), and ACE were in the range of 20.0 to 28.9 GPa, 0.0031 to 0.0085, and 3.41×107 to 10.83×107, respectively. Based on the results, Syzygium was preferred for making the frameboard of violins and guitars. The outer sapwood (outer part) of Syzygium was the most suitable for making frameboard by considering the lowest ACE and highest Q-1. Based on Ed/γ, the inner sapwood (middle part) in Dialium was the most suitable for making soundboard, but based on Q-1 and ACE, heartwood (inner part) was the most preferred for making soundboard. Gymnostoma was also preferred for making soundboard of violins and guitars (inner sapwood) because it yields the highest mean value of Q-1 and ACE. Considering ACE and Q-1, the outer sapwood in Sindora was the best for making frameboard. When considering Ed/γ and Q-1, the heartwood is the most suitable for making the frameboard of violins and guitars. [ABSTRACT FROM AUTHOR]

Microscopic analysis of 36 Brazilian Amazon wood species revealed the presence of silica in 12 species, mostly in the ray cells and a few times in the axial parenchyma and fibers. The average amount of silica in these species varied from 0.07% to 1.6% as quantified by flame atomic absorption spectroscopy (FAAS). Statistical analysis gave the following classification in terms of silica contents: very low (<0.07%), low (between 0.07% and 0.3%: Diplotropis purpurea and Vatairea paraensis), medium (between 0.3% and 0.4%: Chrysophyllum lucentifolium, Couratari multiflora, Dacryodes sp., Mezilaurus itauba, Trattinnickia burserifolia, and Trattinnickia rhoifolia), high (between 0.4% and 0.7%: Astronium gracile and Couratari sp.), and very high (above 0.7%: Apuleia leiocarpa and Couratari stellata). [ABSTRACT FROM AUTHOR]

In the building industry, there is currently a significant lack of information on fire resistance properties of room separation elements made of tropical wood species. The objective of the present study is to fill this gap by investigating the fire behaviour of tropical wood species and subsequently assessing the fire resistance of elements made of this material. In particular, the prime target was to find easy to measure parameters which correlate with both the charring rate and the deflection, the latter caused by fire induced rapid dehumidification. Further, the so found parameters have been investigated for suitability as reliable predictors for fire resistance of fire doors when tropical wood is used as substitute for European native wood. A series of measurements were carried out for tropical and European wood species. Beam deflection and charring rate as well as the fire resistance of doors were measured in standard fire (ISO 834-1). In addition, the oxygen permeability index (OPI) of wood, which appears to have a strong correlation with the charring rate, was measured. It is shown that in consideration of fire resistance both the charring rate and the deflection have to be addressed when tropical wood is used as substitute for European native wood. Finally, it is clearly confirmed that a single parameter such as wood density is not reliable to assess the substitution of an alternative wood species for a species on which fire resistance test results are available. [ABSTRACT FROM AUTHOR]

Acoustic properties such as specific dynamic Young'smodulus (E'/γ), internal friction (Q-1) and acoustic conversion efficiency (ACE) of wood are important properties frequently examined by researchers. Vibration technique is one of the non-destructive evaluation techniques used as an alternative method for measuring the acoustic properties of wood. The objectives of this study are to determine acoustic properties of selected low density tropical wood species namely Endospermum Diadenum, Cratoxylum Arborecens, Dyera Polyphylla, Macaranga Gigantea, Commersonia Bartramia and Alstonia Pneumatophora and their suitability for making violin and guitar (acoustic instruments). The acoustic properties were determined by using free-free flexural vibration method. The results show that there are significant and good relationship between log Q-1/(E'/γ) and log E'/γ with negative gradient for each and overall wood species studied. The P-value of regression equation is less than 0.01 whereas the coefficient of determination (r²) is in the range of 0.565 to 0.894. The mean value of E'/γ, Q-1 and ACE of wood species studied are in the range of 1.69 x 1010 Pa to 2.73 x 1010 Pa, 0.017 to 0.035 and 1.50 x 107 to 3.56 x 107 respectively. Based on the mean value of E'/γ, Endospermum Diadenum, Cratoxylum Arborescens, Macaranga Gigantea and Dyera Polyphylla are preferred for making all component of violin and guitar except for the top plate of violin. Commersonia Bartramia is preferred for making the back plate of violin and guitar, whereas Alstonia Pneumatophora is only preferred for making the back plate of violin. [ABSTRACT FROM AUTHOR]

• Gmelina is a hardwood species with strength characteristics as those of softwoods. • The bending as well as the compressive strength parallel to the grain of Gmelina arborea follows the Weibull distribution. • Gmelina arborea seems to hold the future for the construction industry within the tropics. • Gmelina arborea has absolute potentials for use as a construction material. • The mechanical properties of Gmelina arborea are comparable with those of European spruce and pine. Gmelina arborea is a fast-growing hardwood species whose material properties according to available data have never been properly studied. This work presents an extensive study on the process of acquiring, preparing, testing and all analyses involved in determining the mechanical properties of Gmelina arborea for the design of load bearing structures. Samples obtained from 25-year-old Gmelina trees harvested from a plantation in South Western Nigeria, were transported to the laboratory of the Department of Timber Structures and Building Rehabilitation, University of Kassel where they were seasoned, prepared, and tested in accordance with European and German standards, afterwards, detailed statistical analyses were carried out on the experimental data. While the distribution functions in the Joint Committee for Structural Safety model code were validated for some material properties, they could not be validated for others. The material properties of the hardwood species were found to compare well with those of European softwood species and shows good potentials for use as a construction material. [ABSTRACT FROM AUTHOR]