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Comparison of whole-tree wood property maps based on near-infrared spectroscopic calibrations utilizing data at different spatial resolutions
摘要： Near-infrared (NIR) spectra or NIR-hyperspectral images obtained from radial strips or wood discs provide a cost-effective methodology for examining wood property variation within trees. The calibration used for wood property prediction is critical and can be obtained using two fundamentally different approaches. One involves using a spatial-specific model where wood property data and corresponding spectral data are measured at the same resolution for calibration and prediction, e.g. 10-mm radial increments. The other provides a spatial-interpolated model and involves measuring a property on a broad-scale, e.g. whole-tree, calibrating this data against NIR spectra representing the equivalent scale and then using the calibration to predict the property at higher resolution. To understand the impact of these approaches on subsequent patterns of within-tree variation, whole-tree air-dry density (ADD) and coarseness maps, based on data obtained using the two different approaches, were compared. Patterns of ADD and coarseness variation were comparable indicating that both approaches can be utilized to examine within-tree variation. Spatial-interpolated models have a distinct advantage; being based on whole-tree (or disc) samples, they greatly reduce the cost of wood property analysis and allow the development of maps for properties that are costly and difficult to measure, for example, pulp yield.
关键词： near-infrared spectroscopy,within-tree variation,wood property maps,loblolly pine,coarseness,Pinus taeda,SilviScan,air-dry density
更新于2025-09-16 10:30:52
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Structural characterization of Argania spinosa Moroccan wooden artifacts during natural degradation progress using infrared spectroscopy (ATR-FTIR) and X-Ray diffraction (XRD)
摘要： The present work is focused on spectroscopic study of four samples of Argan wooden artifact pertaining to the 17th, 18th, 20th and 21st centuries. The objective is to characterize their unknown structures by the study of their non degraded parts and to investigate changes occurred in their degraded parts due to the natural degradation process. Attenuated total re?ectance Fourier transform infrared spectroscopy gauges the presence of many functional groups related to cellulose I and/or II (OH, C–O–C and –CH2), hemicelluloses (particularly C?O (cid:2)1), and lignin (OH phenolic, Car-O and C?Car) and provides qualitative information on the state of wood alteration by informing on the evolution of new former C?O bands. The degree of conversion to carbonyl group, especially quinone or p-quinone at 1650 cm (cid:2)1, is correlated to lignin degradation, while the absence of the C?O acetoxy absorption is ascribable to occurred deterioration in hemicelluloses, and (cid:2)1. X-ray diffraction determines the presence of two forms of cellulose; amorphous cellulose at 18.5(cid:3) 2θ and predominant crystalline cellulose Iβ at 2θ ? 22.6(cid:3) which characterized by an intense peak. The decrease of crystallinity index values con?rms the deterioration level and obvious changes in crystallinity level. However, the microcrystalline structure appears unaltered because no signi?cant changes were observed for calculated cristallite seize. The obtained results depend on the prolonged time of ageing, natural deterioration phenomena, and wood part (internal or external) that is exposed to degradation. The combination of these two methods is useful for an accurate estimation of the degradation level of argan wood.
关键词： Chemistry,Argan wood artifact,XRD,Analytical chemistry,Natural product chemistry,Materials Chemistry,Natural degradation,Archaeology,ATR-FTIR spectroscopy,Crystallinity,Lignocelluloses,Structural characterization,Materials Science,Organic chemistry
更新于2025-09-12 10:27:22
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Analysis of stand density effects on the stem form of Norway spruce trees and volume miscalculation by traditional form factor equations using terrestrial laser scanning (TLS)
摘要： Tree and stand volume estimates are relevant for forest inventories, forest sales and carbon stock evaluations. Forest practice commonly uses generalized stem wood volume functions. However, such generalized approaches neglect the stem form in detail. Hence, trees of a given species with the same diameter at breast height (??1.3) and height (h) are always assumed to have the same form factor and thus the same volume. This case study focused on stem form variation of Picea abies due to competition effects. Using terrestrial laser scanning (TLS), we measured the stem shape of 868 trees from a long-term spacing and thinning experiment in Germany. The plots covered a broad density range. We analysed the effect of competition and compared the TLS- with conventionally determined stem volume estimates. TLS-based volume estimations showed that the lower the competition, the lower the tree volume with a given ??1.3 and h. Commonly used functions underestimated the volume stock overall by 4.2 %, disregarding any levels. At plot level, underestimation varied from 0.7 to 7.0 %. At tree level, the volume was over- and underestimated by -10 to +10 %. The more precise the examination, the more suitable the application of TLS for enhancing volume estimation.
关键词： stem wood,volume function,form factor,competition,Tree and stand volume
更新于2025-09-12 10:27:22
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Discrimination of wood species using laser-induced breakdown spectroscopy and near-infrared reflectance spectroscopy
摘要： A new method is proposed for the discrimination of wood species by combining near-infrared reflectance spectroscopy (NIRS) and laser-induced breakdown spectroscopy (LIBS) and using chemometrics for data analysis. The method was applied to the analysis of 42 samples from six different species: Amburana cearensis, Copaifera lucens, Phyllocarpus riedelii, Cariniana legalis, Bowdichia virgilioides, and Aspidosperma pyricollum. The spectra from both techniques were merged on a single data matrix and pretreated by standard normal variate (SNV) and Savitzky– Golay first derivative with smoothing. Principal component analysis was applied to the exploratory data analysis and showed a clear formation of sample groups according to the wood species only when the data from both analytical techniques and the data pretreatment were used. Sample discrimination using partial least squares discriminant analysis was proved possible, but with an average misclassification of about 10%. Sample grouping and discrimination were shown to be probably related to different concentrations of iron, copper, zinc, and/or sodium (affecting the LIBS spectra) and lignin, water, cellulose, and/or hemicellulose (affecting the NIRS spectra).
关键词： wood species discrimination,laser-induced breakdown spectroscopy,near-infrared reflectance spectroscopy,chemometrics
更新于2025-09-12 10:27:22
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Estimating Stand Age from Airborne Laser Scanning Data to Improve Models of Black Spruce Wood Density in the Boreal Forest of Ontario
摘要： Spatial models that provide estimates of wood quality enable value chain optimization approaches that consider the market potential of trees prior to harvest. Ecological land classification units (e.g., ecosite) and structural metrics derived from Airborne Laser Scanning (ALS) data have been shown to be useful predictors of wood quality attributes in black spruce stands of the boreal forest of Ontario, Canada. However, age drives much of the variation in wood quality among trees, and has not been included as a predictor in previous models because it is poorly represented in inventory systems. The objectives of this study were (i) to develop a predictive model of mean stem age of black spruce-dominated stands, and (ii) refine models of black spruce wood density by including age as a predictor variable. A non-parametric model of stand age that used a k nearest neighbor (kNN) classification based on a random forests (rf) distance metric performed well, producing a root mean square difference (RMSD) of 15 years and explaining 62% of the variance. The subsequent random forests model of black spruce wood density generated from age and ecosite predictors was useful, with a root mean square error (RMSE) of 59.1 kg·m?3. These models bring large-scale wood quality prediction closer to becoming operational by including age and site effects that can be derived from inventory data.
关键词： predictive modeling,forest stand age,LiDAR,boreal forest,wood density modeling,black spruce,forest resource inventory,Airborne Laser Scanning (ALS),k-Nearest Neighbor
更新于2025-09-11 14:15:04
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Discrimination of wood and charcoal from six Caatinga species by near-infrared spectroscopy
摘要： Correct identification of species in wood and charcoal commerce is important, and rapid and nondestructive evaluation based on near-infrared techniques can be a good alternative. Four trees from Combretum leprosum, Croton argyrophylloides, Jatropha mutabilis, Luetzelburgia auriculata, Mimosa tenuiflora and Poincianella bracteosa, were cut in a natural forest in the municipality of Coremas, Paraíba state and stem discs with thickness of about 80 mm were taken at 0, 25, 50, 75 and 100% of commercial height. For charcoal production, each sample was wrapped in aluminum foil and carbonized in a muffle furnace, with a final temperature of 450 °C and a heating rate of 1,66 °C min1. Spectra were collected directly from sample surface. The best pretreatment was second derivative, while the best classification method was PCA-LDA, and the analysis of full spectra (4000-10000 cm-1) was indicated. In classification, there was no difference between surfaces where spectra was collected, so in practice, in commercial control for example, the information can be obtained from any surface. For rapid analysis for purposes of control of forest practices or illegal commerce, spectra collected directly from wood and charcoal can be applied to distinguish these six Caatinga species.
关键词： species distinction,spectroscopy,Classification method,wood commerce,wood identification
更新于2025-09-10 09:29:36
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Potential use of nir and visible spectroscopy to analyze chemical properties of thermally treated wood
摘要： The modification of wood by thermal treatments produces characteristic changes in its chemical composition and surface color and can improve the structural and esthetic quality. The objective of this paper is to evaluate the potential of near infrared and visible spectroscopy to predict the modifications in chemical composition of Eucalyptys grandis and Pinus taeda after thermal treatment. Near infrared and visible spectra were collected directly on the longitudinal surface of wood samples. The thermally modified wood of both species showed higher content of lignin and extractives than the untreated wood. There was darkening of thermally modified wood, as a result of chemical modification caused by heat. The Near infrared/visible technique identified the groups that were modified by treatment. NIR and visible spectroscopy can be used to predict chemical composition of natural or thermally treated Eucalyptus grandis and Pinus taeda.
关键词： Eucalyptus grandis,Pinus taeda,wood composition,Chemical analysis,wood color,thermal modification
更新于2025-09-09 09:28:46
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Linear Sensor Arrangement for Softwood Grain Angle Measurements by Directional Reflection
摘要： A linear sensor arrangement is presented as a means of measuring the three-dimensional grain angle of wood. The measurement principle is based on an optical characteristic of a wood surface where the microscopic cell structure causes preferential reflection of light perpendicular to the wood grain. This response is notable among the several other techniques for measuring wood grain angle in that it enables identification of diving (out-of-plane) angle in addition to the surface (within-plane) angle. The basic measurement principle has been previously investigated using a circular array of light sensors to measure the spatial distribution of the light reflected from a wood surface. That procedure works reasonably well for surface points near the center of the circle and for modest dive angles. The linear sensor arrangement investigated here is designed to extend measurement functionality so as to be able to measure grain angle at any point along a central line and over a greater range of dive angle. A prototype scanner system is presented together with example experimental results for clear wood samples and for a face knot sample.
关键词： fibre direction,grain angle,wood surface reflection,tracheid effect
更新于2025-09-09 09:28:46
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Ultra-short Echo Time Imaging with Multiple Echo Refocusing for Porous Media T2 Mapping
摘要： T2 relaxation time measurement is a powerful tool to distinguish signal components in porous media. As T2 weighting is generally achieved by spin-echo based methods, it is very challenging to capture very short T2 relaxation time components, approximately 1 ms, with high resolution spatial encoding. It is especially challenging when T2 relaxation times of the other signal components are not known a priori. We propose a method, combining ultrashort echo time (UTE) imaging with multiple spin echo refocusing, to generate a series of images with T2 weighting. The T2 decay curves for each image voxel were extracted, and multiple T2 relaxation components were quantitatively evaluated. The method has been applied to a fast relaxation system, namely, moisture content in wood samples to differentiate cell wall (bound) water and cell cavity (lumen) water.
关键词： cell wall water,spin echo,wood,T2 mapping,lumen water,k-space,radial,UTE
更新于2025-09-09 09:28:46
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Photocatalytic Degradation of Wood Coated with a Combination of Rutile TiO2 Nanostructures and Low-Surface Free-Energy Materials
摘要： To test the hypothesis that wood coated with rutile TiO2 nanostructures can undergo degradation because of the photocatalytic activity of TiO2, three sets of wood specimens were aged at an accelerated rate. These three sets consisted of blank wood (BW), HDTMOS/MTMOS-coated wood (WHM), and TiO2/HDTMOS/MTMOS-coated wood (WTHM). After exposure to 155-h UV irradiation, the wettability of WTHM changed from hydrophobic to hydrophilic. This indicated that the initial low-surface free-energy materials underwent degradation because of the photocatalytic activity of TiO2. After exposure to 960 h of UV light irradiation and water spray, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA) of WTHM showed that rutile TiO2 nanostructures had partially peeled off the wood surface. This suggested that the adjacent wood surface also suffered degradation because of the photocatalytic activity of TiO2. Although the rutile TiO2 coating noticeably enhanced the color stability during UV light aging, it made a relatively small contribution to the color stability of the wood during UV light and water spray weathering process. This study suggests that to derive the greatest benefit from modification of wood surfaces with rutile TiO2 nanostructures for weathering resistance, it is necessary to take measures to inhibit the photocatalytic activity of TiO2 or to fix the TiO2 coating on the wood surface.
关键词： Coating,Hydrophobic,Rutile,Wood,Titanium dioxide,Weathering,Nanostructure,Photocatalytic
更新于2025-09-04 15:30:14