Wood Rays Research Articles

Effect of delignification on shrinking and swelling of poplar wood assessed using digital image correlation technique.

This study investigates lignin's influence on the hygroscopic behavior of poplar wood. Delignification was achieved using an acidic NaClO2 solution, and digital image correlation (DIC) was employed to measure strain distribution during shrinking and swelling across relative humidity (RH) ranging of 0 % to 97 %. Results showed that lignin removal increased equilibrium moisture content (EMC) by up to 3.6 % in samples with 27 % lignin reduction. Strain analysis revealed significant radial strain differences between earlywood and latewood, with tangential strain suppressed by wood rays. Increased porosity and cellulose slippage were observed following lignin removal, and samples with the highest lignin removal rate exhibited reduction exhibited over 58 % greater εxx and over 43 % greater εyy compared to untreated wood. These effects were most pronounced in latewood and regions distant from wood rays, where stress concentrations occurred. Delignification-induced cell wall thinning amplified the wood rays' inhibitory effect on anisotropic deformation during shrinking，enhancing the contrast between isotropic deformation in latewood and anisotropic deformation in earlywood during swelling. These findings provide insights into lignin's role in wood-water interactions, supporting the optimization of wood modification techniques.

A Fossil Dicot Wood form the Deccan Intertrappean Beds of Marzari, Nagpur, (India)

A well preserved dicot wood was collected form (Lat 21*,30, to22*,55, N) and long 78*,15 to79*,20 E which was found in intertrsppean locality of Marzari Nagpur District M.S. The present investigation a black color fossiliferous wood is dicotyledonous diffuse, porous vessels mostly solitary and radial multiples of two Perforated simple plate. Intravascular pit pairs alternate, bordered, parenchyma, Para tracheal, vasciicentric wood rays mostly multiiseriate and composed of heterogeneous cells, uniseriate rays mostly homogenous fibers short, thin walled no septate. The wood through shows some characters of the present day families like Menispermaceae, Dipterocarpaceae, Anonnaceae, Lythraceae. It has close affinities with the members of family Anonnaceae It could not conclusively be traced to any particular genus but it broadly placed under the family Anonnaceae. The chief characteristics features wood is diffuse porous, oblique septate and non- steroid the affinities with the family Anonnaceae and hence named as sheikhoxylon mahuzarii after its locality.

Relationship between structural characteristics of growth rings and strain accumulation in thermally modified Douglas fir wood during compressive test

ABSTRACT Evaluating and predicting mechanical properties according to structural characteristics of growth rings contributes to effective production and application of wood. Specimens, from Douglas fir wood, were compressed under perpendicular-to-grain load along the transverse direction of wood, and strain distribution was simultaneously recorded using digital image correlation (DIC). Growth-ring orientation, latewood ratio, width of latewood, and shear strain were obtained at hundreds of spots in earlywood adjacent to a growth ring. The compression ratio negatively relates to both the width of the latewood and the latewood ratio of the specimens. Shear strain is prone to accumulate in regions where growth-ring orientation deviates from 90° or −90°. Shear strain homogenously distributes along growth rings when growth-ring orientation is uniform and around 65°. For both with and without thermally modified specimens, there is a linear relationship between shear-strain value and structural characteristics. For the specimens without thermal modification, the location of shear-strain accumulation is possible to be predicted based on this relationship. Shear-strain accumulation is attributed to the deformation of cells in earlywood and cracks in latewood. The direction of cracks is along with wood rays and the boundary between latewood and earlywood when the growth-ring orientations are approximately 80° and 65° respectively.

Study on the influence of wood ray morphological characteristics on the tensile strength of wood parallel to grain

The tensile strength of wood parallel to grain is one of the important indicators of wood physical and mechanical properties. Cross-sectional shape possesses a significant effect on the tensile strength parallel to grain, especially for broad-leaved trees with broad wood rays. However the influence of the structural feature of wood rays on the test results, which was commonly ignored. The article focuses on the beech tree with two types of wood rays: broad and narrow, poplar wood with extremely fine wood rays, and dilleniad with extremely rich wood rays. The relationship between the inclination angle and fracture mode of wood rays and the microstructure of wood rays is studied, in order to provide a more accurate scientific basis for determining the tensile strength of wood parallel to grain. The results showed that the inclination angle between the wood ray and the tensile direction has a significant impact on the fracture mode and tensile strength, and the tensile strength parallel to grain without inclination angle is greater than that with inclination angle. Different types of wood rays have a effect on the coefficient of variation of the tensile strength parallel to grain of the specimen. Under the same inclination angle, the Pearson correlation between the wood ray parenchyma ratio and the tensile strength parallel to grain is significantly negative at the 0.01 level (double tailed) or 0.05 level (double tailed). Besides, as the wood ray parenchyma ratio gradually increases, the overall tensile strength of wood parallel to grain shows a downward trend. The fracture surface morphology characteristics of specimens with different fracture modes are different.

Datiscaceoxylon baradii gen.et sp.nov, a Fossil Dicot Wood from the Deccan Intertrappean Beds of Mahurzari, Nagpur, India

A petrified wood related to the family Datiscaceae was collected from the Deccan Intertrappean Series of India. The present wood found well preserved in the barad, Mahurzari near Nagpur, Maharashtra State, India. Wood is diffuse porous, tylosed, vessels solitary and in multiples of two to four, perforation plate simple, intervascular pit pairs alternate and bordered, xylem parenchyma paratracheal vasicentric, wood rays biseriate and homogenous, fibres non-septate and non-storied. Comparison is made with the modern families like: - Passifloracea, Onagraceae, Combretaceae, Oxalidaceae and Datiscaceae. It shows great affinities with the family Datsicaceae and hence named as Datiscaceoxylon baradii gen.et sp.nov. The generic name has been assigned on the basis of its affinities with the family and the specific name is after the locality.

User Preferences on the Application of Wooden Wall Coverings in Interiors Made of Oak Veneer Residue

Guided by the principles of visual perception and basic design, this research was conducted to examine users’ preferences on how they perceive natural unique wood phenomena of Pedunculate Slavonian Oak veneers (Quercus robur L.) such as color changes, wood rays, sapwood, and knots, which in the production and technical sense represent defects and wood residue, but could be used in the design of sustainable and ecological wall decorations. The goal was to detect samples with the most positive attributes and to observe their connection with activities and functional space if they are viewed as wall coverings in the interior. The results confirm that discoloration and wood rays are considered the most harmonious (“prettiest”) decors. Discoloration is associated with quiet cognitive or medium-intensity activity that can be used in libraries, hotel rooms, and classrooms. Wood rays are connected with very quiet activity in ambulance waiting rooms or religious buildings and museums. Knot decors are considered the most natural and are recommended for interiors with very or medium-intensive activities such as restaurants, cafes, and hotel receptions, but attention should be paid to the way the wall decors are arranged on the walls. Sapwood–hardwood decors are the subject of further research and improvement concerning the relationship between the dark and light parts of the veneer. In conclusion, the results provide useful guidelines for manufacturers with a large veneer residue in production and who want to design decorative wall panels, as well as for designers and architects designing interiors for a specific purpose and function where certain user behavior and psychological stimulation are desired.

Opening the black box: explainable deep-learning classification of wood microscopic image of endangered tree species

BackgroundTraditional method of wood species identification involves the use of hand lens by wood anatomists, which is a time-consuming method that usually identifies only at the genetic level. Computer vision method can achieve "species" level identification but cannot provide an explanation on what features are used for the identification. Thus, in this study, we used computer vision methods coupled with deep learning to reveal interspecific differences between closely related tree species.ResultA total of 850 images were collected from the cross and tangential sections of 15 wood species. These images were used to construct a deep-learning model to discriminate wood species, and a classification accuracy of 99.3% was obtained. The key features between species in machine identification were targeted by feature visualization methods, mainly the axial parenchyma arrangements and vessel in cross section and the wood ray in tangential section. Moreover, the degree of importance of the vessels of different tree species in the cross-section images was determined by the manual feature labeling method. The results showed that vessels play an important role in the identification of Dalbergia, Pterocarpus, Swartzia, Carapa, and Cedrela, but exhibited limited resolutions on discriminating Swietenia species.ConclusionThe research results provide a computer-assisted tool for identifying endangered tree species in laboratory scenarios, which can be used to combat illegal logging and related trade and contribute to the implementation of CITES convention and the conservation of global biodiversity.

A Comparative Analysis of Oak Wood Defect Detection Using Two Deep Learning (DL)-Based Software

The world’s expanding population presents a challenge through its rising demand for wood products. This requirement contributes to increased production and, ultimately, the high-quality and efficient utilization of basic materials. Detecting defects in wood elements, which are inevitable when working with a natural material such as wood, is one of the difficulties associated with the issue above. Even in modern times, people still identify wood defects by visually scrutinizing the sawn surface and marking the defects. Industrial scanners equipped with software based on convolutional neural networks (CNNs) allow for the rapid detection of defects and have the potential to accelerate production and eradicate human subjectivity. This paper evaluates the suitability of defect recognition software in industrial scanners against software specifically designed for this task within a research project conducted using Adaptive Vision Studio, focusing on feature detection techniques. The research revealed that the software installed as part of the industrial scanner is more effective for analyzing knots (77.78% vs. 70.37%), sapwood (100% vs. 80%), and ambrosia wood (60% vs. 20%), while the software derived from the project is more effective for analyzing cracks (70% vs. 65%), ingrown bark (42.86% vs. 28.57%), and wood rays (81.82% vs. 27.27%).

The Effect of Rays on the Mechanical Behaviour of Beech and Birch at Different Moisture and Temperature Conditions Perpendicular to the Grain

The plastic deformation of wood perpendicular to the grain is gaining increasing importance due to advancements in forming technologies and the densification of wood. This study investigates how two hardwood species, i.e., beech (Fagus sylvatica) and birch (Betula pendula), respond to compression in the radial direction and examines the structural changes they undergo during both elastic and plastic deformation. Stress–strain curves at different moisture contents (dry to wet) and temperature conditions (20 to 140 °C) were recorded. In-situ observations at high moisture content and temperatures by means of different microscopic techniques are practically unfeasible. Therefore, the specimens were analysed ex-situ microscopically after the test. In addition to the compression of transversely oriented fibres and vessels, special attention was paid to the deformation behaviour of the wood rays. The results suggest that the wood ray cells carry a relatively higher proportion of the load in the radial loading direction than the surrounding vessels and fibres. This observation is supported by the higher percentage of deformed vessels, seen in the microscopy, in areas where the rays developed kinks, usually in the early wood of beech and anywhere in the cross-section of birch. The weaving of rays around big vessels introduced shear strains under compressive stresses at the kinked rays’ area. Thus, shear deformation is more evident in early wood than in late wood regions of wood. However, when the wood was tested at elevated moistures and temperatures, the material demonstrated a ductile response, namely the absence of localised shear deformations. Notably, wet beech and birch specimens heated to 100 °C and above exhibited pronounced thickness recovery and there was slightly irreversible buckling of rays and vessel deformations. Therefore, under such conditions, wood behaves like a “sponge” and is expected to be successfully processed without introducing clear damage to the material. This characteristic holds promise for replication in the development of bio-based energy-absorbing materials.

VARIABILITY OF ANATOMICAL AND MORPHOLOGICAL TRAITS OF PINUS NIGRA AND PINUS SYLVESTRIS SEEDLINGS AFFECTED BY DIFFERENT CONTAINER TYPE

In the paper was analysed the influence of three different container types, used for cultivation of Pinus nigra and Pinus sylvestris seedlings, on dimensions of their anatomical (resin ducts width, resin ducts number, tracheid number, tracheid width, wood rays height) and morphological (height, root collar diameter, sturdiness coefficient) elements, and on proportion of wood, bark and pith, as well. Two-factorial ANOVA showed that container type affects a lot all investigated anatomical traits by both species, but on the other side, these species varied between each other just in terms of tracheid width and wood rays height. Based on descriptive statistics, significantly lower values of all studied anatomical elements were recorded by biodegradable compared to plastic containers. As for P. nigra seedlings, they showed the best anatomical performance in Plantagrah I, while Hiko V-120 SS was the most suitable for P. sylvestris. The highest proportion of pith and bark was recorded in biodegradable container. As for morphological parameters, such as height and root collar diameter, higher values were recorded by plastic containers.

Evaluation of Wood Anatomical Properties from 18 Tree Species in the Subtropical Region of China

The subtropical region of China possesses abundant broad-leaf tree species resources; however, the anatomical properties and microstructure of the wood are still unclear, which restricts the processing and utilization of wood. In this study, 14 broad-leaf trees and four coniferous trees were selected. Wood anatomical indices and wood microanatomy were used to evaluate the wood properties using a comprehensive index method. The results have shown that Dalbergia assamica exhibited the highest wood basic density among the 14 broad-leaved tree species, accompanied by a significant fiber proportion and vessel lumen diameter but a small vessel proportion and a high number of wood rays. Conversely, Parakmeria lotungensis and Michelia chapensis had relatively low wood basic densities, rendering them less suitable as valuable broad-leaved wood sources. Altingia chinensis, Castanopsis kawakamii, and the remaining 11 tree species exhibited medium-level wood basic densities. The 14 broad-leaved tree species had medium-length fibers. Phoebe bournei, Dalbergia assamica, and Castanopsis kawakamii demonstrated relatively high fiber proportion. Altingia chinensis, Dalbergia assamica, and Castanopsis kawakamii exhibited a large number of wood rays, making their wood more susceptible to cracking, whereas other broad-leaved tree species possessed fewer wood rays. The findings have provided a scientific basis for the exploration of precious broad-leaved tree resources and wood use.

Swelling of beech wood (Fagus sylvatica L.) during gaseous ammonia treatment as a function of pressure

AbstractThis paper deals with the optical observation and evaluation of the swelling of beech wood samples (Fagus sylvatica L.) during gaseous ammonia treatment. The pressure level was varied in several experiments from ambient pressure to almost saturated steam pressure at isothermal conditions at 20 °C. The initial moisture content of the wood was oven dried and also conditioned (65% RH/20 °C). All experiments were carried out in a self-developed experimental setup. It consisted of three parts: a pressure vessel with a glass pane at the top, a camera with additional lighting above it and an algorithm for the semi-automatic evaluation of the data. Parallel investigation of the maximum swelling in water of specimens of the same origin showed that ammonia leads to a higher swelling in tangential direction (up to 23%). The swell-inhibiting influence by the wood rays can be observed on the basis of the comparison to the water swelling in radial direction. Furthermore, the results visualise the change in crystal structure from cellulose I to ammonia-cellulose I.

Spatial organization and connectivity of wood rays in Pinus massoniana xylem based on high-resolution μCT-assisted network analysis.

Spatial organization and connectivity of wood rays in Pinus massoniana was comprehensively viewed and regarded as anatomical adaptions to ensure the properties of rays in xylem. Spatial organization and connectivity of wood rays are essential for understanding the wood hierarchical architecture, but the spatial information is ambiguous due to small cell size. Herein, 3D visualization of rays in Pinus massoniana was performed using high-resolution μCT. We found brick-shaped rays were 6.5% in volume fractions, nearly twice the area fractions estimated by 2D levels. Uniseriate rays became taller and wider during the transition from earlywood to latewood, which was mainly contributed from the height increment of ray tracheids and widened ray parenchyma cells. Furthermore, both volume and surface area of ray parenchyma cells were larger than ray tracheids, so ray parenchyma took a higher proportion in rays. Moreover, three different types of pits for connectivity were segmented and revealed. Pits in both axial tracheids and ray tracheids were bordered, but the pit volume and pit aperture of earlywood axial tracheids were almost tenfold and over fourfold larger than ray tracheids. Contrarily, cross-field pits between ray parenchyma and axial tracheids were window-like with the principal axis of 31.0μm, but its pit volume was approximately one-third of axial tracheids. Additionally, spatial organization of rays and axial resin canal was analyzed by a curved surface reformation tool, providing the first evidence of rays close to epithelial cells inward through the resin canal. Epithelial cells had various morphologies and large variations in cell size. Our results give new insights into the organization of radial system of xylem, especially the connectivity of rays with adjacent cells.

Behaviour of hybrid cross laminated timber in compression perpendicular to grain in different layup structure, support conditions, and loading configurations

Cross laminated timber (CLT) is recognized as alternative to traditional construction materials. As a floor member, it causes the compressive deformation or even damage perpendicular to the grain of CLT due to vertical load imposed by the column or wall. The challenge is how to improve the compressive strength (fc,90) and elastic modulus (Ec,90) perpendicular to the grain under the high diversity of possible load configurations. Compared with normal CLT, hybrid CLT (HCLT) used structural composite materials (e.g. laminated strand lumber) instead of timber, which had more homogeneous mechanical properties. In this study, the spruce-pine-fir (SPF) and laminated strand lumber (LSL) were used to prepare HCLT. The full surface loading, point loading representing columns and line loading representing walls of HCLT in the perpendicular to grain direction were carried out. The results show that fc,90 increased with increasing thickness ratio of LSL in the total thickness of HCLT under full surface loading, the highest increase in strength of HCLT reached 35.71 %, data of Ec,90 had the opposite conclusion. In the case of point loading, the fc,90 and Ec,90 under discretely support was lower than those under successively support. Load configuration had significant influence on the fc,90 and Ec,90 including middle position (M), corner position (C), edge parallel (E) and edge vertical (V) to the grain of the outer layer. In the case of line loading, it was in good agreement with point loading results, and fc,90 and Ec,90 under line loading were lower than that under point loading. The failure modes were mainly the cracks along the wood ray direction of SPF material, while no obvious damage for LSL under full surface loading. In addition, the failure modes mainly of local loading included the shear failure for SPF material, fiber fracture failure of LSL material and the adhesive layer cracking in the non-directly compression zone.

Effects of wood texture and color on aesthetic pleasure: two experimental studies

The texture and color on wood are key factors that influence an individual's perception of it. However, little research has been done to confirm what kind of pattern in textures and colors are more likely to evoke individual aesthetic pleasure. Therefore, twenty-four decorative wood from northern China were selected, identified, and quantified in their colors with a CR-5 Colorimeter. We picked out eight kinds of wood with optimal texture characteristics through feature-fusion wood grain recognition (FWGR) and enhanced the texture features with photoshop in VR space. The result show that, in the color dimension, woods in the hue range of 20-25 and saturation of 65-75 were considered beautiful for individual perception of aesthetic. In the texture dimension, the size of the space affects the individual's preference for texture. When the pattern of the wood ray is continuous and clear, the individual's perception of its fluidity is enhanced; while for the fuzzy and interrupted pattern of the wood ray, the individual does not follow the fluidity of the line but focuses on the overall uniformity.

Visualization of wood cell structure during cellulose purification via high resolution X-ray CT and spectroscopy

Wood is a heterogeneous material with multiple scales. Revealing the three-dimensional structure of wood tissue in multiple dimensions works as a prerequisite for the reorganization, modification and high-value utilization of wood. By adopting high resolution X-ray micro computed tomography (XμCT), the three-dimensional structural changes during cellulose purification were reconstructed. In the meantime, the changing process in the chemical composition of wood cell wall was demonstrated in situ using laser Raman spectroscopy imaging technology. Moreover, cellular changes on a two-dimensional scale were observed by ordinary optical, fluorescence, and polarizing microscopes respectively. XμCT results indicated that the disruption of the cell structure of chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) by purification treatment started between the diameter walls of the tracheids, while that of the poplar (Populus sp.) cell structure started between the vessels or between the vessels and the wood rays. Such kind of disruption in cell structure was more pronounced after the hemicellulose was removed, with adjacent cells scattered and deformed. In the first step of matrix removal, the cell wall got thinner primarily out of lignin removal, while in the process of hemicellulose removal, the cell wall swelled with the lye. The Raman images illustrated that the distribution of purified cellulose in the cell wall was related to the degree of cell disruption. In undeformed cell walls, the cellulose was evenly distributed, whereas in shrunken and deformed cell walls, it was unevenly scattered.

STUDY ON THE DECAY EXTENT OF WOODEN COMPONENTS OF DANXIA TEMPLE ANCIENT BUILDING BY POLARIZED LIGHT, FLUORESCENCE AND X-RAY DIFFRACTION METHODS

In the present study, the decay extent of wooden components from the Halls of Pilu and Tianran ancestor of Danxia Temple ancient buildings was observed by polarized light, fluorescence, and XRD methods. The findings of the investigation can be summarized as follows. Sample No. 1 was identified as red birch wood (Betula albo-sinensis) and sample No. 2 was identified as maple wood (Pterocarya stenoptera). The brightness of crystalline cellulose birefringence in the cell walls of vessels, wood rays and wood fibres, both in decayed red birch wooden components (DRBWC) and in decayed maple wooden components (DMWC), was not obvious, indicating that the cellulose was seriously consumed by fungi. However, the brightness of green fluorescence in the cell walls of both DRBWC and DMWC was very evident, indicating that the lignin was mainly retained or was not consumed by fungi. XRD analysis indicated that wood decay fungi did not change the structure and crystal layer distance of the crystallization zone, but the diffraction intensity decreased to a certain extent. The crystallinity of cellulose was reduced by 11.16%, from 43.29% to 38.46%, in DRBWC and by 52.16%, from 40.68% to 19.46%, in DMWC, demonstrating a reduction in crystalline cellulose. The degradation of cellulose in wooden components will eventually lead to a reduction in their load-bearing capacity. According to the tendency of brown rot fungi of consuming mostly cellulose and hemicelluloses while avoiding lignin, we concluded that both DRBWC and DMWC were seriously degraded by brown rot fungi, in addition to the attack of termites. The low resistance of the two wooden components to fungal decay and termites is the main cause of their deterioration. The results on the extent of decay will provide scientific data for the future conservation and restoration of the Danxia Temple relics.

Ancient plastid genomes solve the tree species mystery of the imperial wood “Nanmu” in the Forbidden City, the largest existing wooden palace complex in the world

Societal Impact StatementCombining natural and social science approaches to conduct archeological research on wooden cultural relics is important for exploring major aspects of ancient civilizations. The Forbidden City in Beijing, China, is the largest existing wooden palace complex in the world. We examined ancient DNA of imperial wood “Nanmu” specimens taken from representative structural components of the Forbidden City, in order to provide a new perspective on the long‐standing dispute about its species. This allowed us to accurately identify and properly restore these wooden artifacts and improved our understanding of the past interactions between plant distribution, forest resources, and human activities.Summary Exploring the life styles and production methods of past generations using plant resources can help us to improve our understanding of human civilization. Nanmu, known for its high wood quality, was exclusively used for imperial palace construction in the 15th–19th centuries in China, yet its species has been a subject of long‐standing debate. Here, we revisit this unresolved problem, using morphology and ancient DNA (aDNA) to analyze 21 centuries‐old Nanmu specimens sampled from representative palaces of the Forbidden City. Cytochemical staining demonstrated that endogenous aDNA sporadically occurs in the wood ray parenchyma cells of Nanmu specimens. High‐quality plastid genomes were retrieved from archeological woods for the first time via an aDNA capture method, with 90%–100% coverage (137,663–152,805 bp) and sequence depths of 27.05‐ to 1409.94‐fold. Utilizing these ancient genomes, our results demonstrate that Phoebe zhennan and Phoebe hui are most likely the main species of Nanmu in the Forbidden City. This finding diverges from the prevailing view that Nanmu encompasses woods from the whole genus Phoebe and even its close relative Machilus. It also shows that stringent criteria were used when selecting construction materials for the Forbidden City. By combining morphological traits with aDNA analyses, we provide a new solution for identifying the species of timber used for ancient architecture, and we increase our understanding of the way in which forest resources were recognized and utilized by our ancestors despite the lack of a plant taxonomic framework in ancient times.

CT investigation of 3D liquid pathways in the anatomical structure of Norway spruce wood during imbibition

Abstract Wood permeability is a macroscopic property resulting from complex pathways at the cellular level. In this study, high-resolution X-ray CT scans were performed during longitudinal imbibition in Norway spruce to investigate the role of wood rays and tracheids network in liquid migration. A customized setup was designed to maintain the bottom face of a wooden cylinder in contact with water, without vibration, despite the sample rotation required during each scan. The results highlighted a contrasted role of latewood and earlywood in water migration. Liquid imbibition was fast in latewood, because the bordered pits are less prone to aspiration than in earlywood, due to their smaller diameter and larger cell wall thickness. In earlywood, the migration pattern was complex due to pit aspiration that isolate tracheids clusters. Indeed, the images revealed a significant contribution of wood rays in the migration pathways. Consequently, tracheids were not progressively filled in the longitudinal direction from one tracheid to the next, but they were filled laterally with water coming from wood rays at different heights of the cells. This explained entrapped air bubbles in the lumens and led to a 3D heterogeneous liquid distribution.

Anatomical and topochemical features of the genera Acacia, Acaciella, Senegalia and Vachellia

Summary Molecular research has shown that the genus Acacia is in fact polyphyletic. The discussion about grouping the species of Acacia s.l. into monophyletic genera kept two International Botanical Congresses (Congresses 17 and 18) occupied and resulted in the general acceptance of the genera Acacia, Acaciella, Mariosousa, Senegalia and Vachellia. This raises questions about whether the wood of these new genera can be distinguished using established wood identification methods. Anatomical features of members from Acacia, Acaciella, Senegalia and Vachellia were examined and compared using transmission light microscopy. Topochemical characteristics were investigated using UV microspectrophotometry (UMSP) to identify differences in the distribution of phenolic compounds and cell wall lignification. The current study shows that the presence as well as the arrangement and dimensions of the axial parenchyma, as well as the height and width of the wood rays and fibre dimensions allow anatomical differentiation of the species studied. UMSP revealed the presence and distribution of phenolic compounds and differences in the degree of lignification between the genera. The aim of this paper is to highlight the potential of the applied methods to differentiate between the genera.