Tropical Wood Research Articles

Analyzing the Impact of EU’s Legality Requirements Policies on Sustainable Timber and Sawnwood Trade—Focusing on Tropical Wood Trade

This study analyzes the impact of the EU′s policy to prohibit the import of illegally harvested timber on the trade of tropical timber and sawnwood. The analysis uses a difference-in-differences approach based on gravity models, with panel data from over 193 countries that trade tropical timber and sawnwood. The result of the analysis shows that the European Union Timber Regulation (EUTR) reduces the trade of illegally harvested timber. It further suggests that the EUTR caused a relatively larger reduction in tropical sawnwood (−0.21%) than that of tropical timber (0.07%). In addition, the Voluntary Partnership Agreement (VPA) appeared to cause a significant reduction in tropical sawnwood (−0.07~−0.05%), whereas tropical timber did not appear to have been significantly impacted. In particular, the reduction in timber exports in countries that have signed the VPA, which aims to encourage exports of legally produced timber, has significant implications for both the EU and timber exporters preparing for the VPA, as both parties strive to expand the VPA. The results of this study suggest that the EU needs to make additional efforts to address the decline in exports from countries that signed the VPA.

Technological characterization of tropical woods from the genus Eperua (Fabaceae)

ABSTRACT In the Amazon basin, effective forest management plans are essential for sustainability, as they promote the exploration of new species. The Fabaceae family, which is abundant in tropical forests, includes tree species with timber potential, but gaps remain in understanding their properties. This study investigated the chemical and physicomechanical properties of Eperua from the Brazilian Amazon. Trees were randomly collected from native forests in Amazonas/Brazil. The samples were analyzed to determine their chemical and physicomechanical traits. The results revealed that Eperua falcata had high concentrations of extractives and lignin (15% and 27%, respectively), whereas Eperua leucantha and Eperua purpurea presented relatively high holocellulose contents, reaching up to 66%. The physicomechanical properties indicated a low moisture content (dry matter > 90%) and densities ranging from 620 to 900 kg m−3. All the samples had anisotropy values <1.8%. E. falcata and E. schomburgkiana presented the highest values for higher heating value, modulus of elasticity, rupture, and hardness. The analysis of the chemical composition, along with the physical and mechanical properties of the woods from the genus Eperua, reveals significant potential for applications in sustainable construction and high added-value products, particularly in sectors requiring durability and resistance, such as civil construction and furniture manufacturing.

Clustering of tropical species through multivariate analysis of the bonding properties of edge-glued panels (EGP)

Tropical woods have high added value, and the use of waste for panel production is an initiative to add more value to this material, typically consisting of various species. The use of raw materials from tropical solid wood waste in the Amazon region contributes to the reduction of carbon emissions associated with the burning of this material. In this context, this study aimed to cluster species based on the bonding properties of Amazonian woods by applying multivariate analysis. The apparent density 12% and strength of finger joint and edge-glued joints of Cedrela odorata, Enterolobium schomburgkii, Erisma uncinatum and Qualea paraensis was evaluated which were joined in homogeneous and hybrid configurations with the adhesives PVA and EPI, as spreading rate of 180 g/m2. The treatments were compared by multivariate analysis of variance and discriminant analysis. The discrimination of species and combinations based on wood density (low, medium, and high) revealed that this is the most important characteristic for grouping different species that make up tropical hardwood waste for the production of EGP panels. In practice, the separation of species into groups according to wood densities can contribute to a better definition of the indications for use of edge glued panels of each density class, and assertive targeting for applications according to the strength ranges required. In the static bending, parallel tensile and shear tests all species and their combinations met the minimum requirements normative, indicating the approval of species and combinations studied for the production of EGP panels.

Role of extractives on the weathering of tropical and temperate wood species in two above-ground fields: coastal or terrestrial

The effect of heartwood extractives on natural weathering of 5 temperate (juniper, walnut, oak, pseudoacacia, and chestnut) and 9 tropical (wenge, teak, iroko, dahoma, moabi, okan, padauk, ipe, and tatajuba) wood species against abiotic degrading agents at two sites was investigated. Wood species were exposed to three-stage extraction, then extracted and un-extracted samples were exposed outdoors for 12 months in two above-ground test sites, coastal or terrestrial. Samples were evaluated regarding moisture content, color change, surface roughness, and surface chemistry (ATR-FTIR) at 1, 3, 6, and 12 months of exposure. Results indicate that roughness and color change increased as the exposure time increased. Among the temperate species, the least rough surfaces were found in juniper, while iroko, ipe, and wenge were for tropical species. The location did not statistically affect roughness. Temperate species generally showed rougher surfaces than tropical species. The remarkable color change occurred in the first 3 months in temperate wood species and between 3 and 6 months in extractive-rich tropical wood species. The highest color change was seen in samples extracted and exposed on the terrestrial test site, while the lowest was in un-extracted samples exposed on the coast. Padauk had the most color change, while moabi had the least. The surfaces of temperate species showed darkening while the surfaces of tropical species showed lightening during the weathering exposure. FTIR studies confirmed that the change in the surface chemistry of temperate species mostly occurs in the first month, while surface degradation of some tropical species can take up to 3 months.

Wood properties of three south american species planted in consortium

The use of tropical wood species in reforestation can be an alternative resource to meet the demand from the industrial wood sector. However, this strategy remains very limited, even while tropical forests continue to be deliberately exploited for the selective extraction of native species of highly commercial value. To test the potential of tropical species in reforestation, it is first necessary to evaluate the production and quality of the wood produced. Therefore, this study aimed to evaluate the quality Astronium urundeuva, Astronium fraxinifolium and Terminalia argentea woods, all aged 22 years, from a heterogeneous plantation located in the municipality of Selvíria-MS. From each species, 15 trees were selected. A 10 cm thick disc was removed from the base of each tree. Samples were taken from the discs near the bark region to evaluate the anatomical characteristics and the physical and mechanical properties of the wood. According to the results, it was found that only compressive strength did not differ significantly among the species. Astronium urundeuva presented the highest values for basic density and apparent density, and Terminalia argentea presented the highest values for fiber length, fiber wall thickness and vessel element diameter. The best Pearson correlations were found for basic density and apparent density, both for Astronium fraxinifolium and Astronium urundeuva. The best regression equations obtained were correlations between basic density and apparent density for Astronium fraxinifolium and Astronium urundeuva. The linear model best fits the data for these correlations. The greater growth of Terminalia argentea trees caused lower wood density owing to the lower rate of competition among trees. Based on the results and according to wood strength standards, the three species can be classified in the D40 strength class. According to the obtained results, these can support information to be compared with some species used commercially for structural purposes and other uses.

Relationship between characteristic values of shear strength parallel to grain and tensile strength perpendicular to grain for tropical woods

Wood, due to its complex anatomy, requires meticulous characterization that imposes several tests to be carried out to evaluate its properties. Normative codes adopt different specimens to this aim. Geometric specificities proposed by NBR 7190-3:2022 and ASTM D143-22 to specimens used for estimating wood strength in tensile perpendicular to grain (ft90) make them difficult to carry out. Thus it is advisable to consider relating ft90 with another mechanical property, for example, the shear strength parallel to the grain (fv0). This paper aims to establish a coefficient relating the characteristic values of ft90 and fv0, for strength classes D40 and D60 (frequently used for structural purposes) of Brazilian Code 7190:3-2022. A further aim, if possible, is to determine a single representative coefficient for both classes. Tests made it possible to obtain those properties for four species from each class, following NBR 7190-3:2022 guidelines. The optimal coefficient was determined using the least squares method (MMQ). Ratios ft90,k/fv0,k were 0.22 and 0.19, for classes D40 and D60, respectively. As these ratios don’t present a significant difference, it is viable to adopt a single relationship for both classes, thus simplifying characterization procedures.

Damping properties of some tropical wood species determined by free transverse vibration method

ABSTRACT This article describes a non-destructive method for determining the damping properties of wood. It was based on the analysis of the attenuation of the free transverse vibrations of a fixed support-free specimen following excitation. Cameroonian forests abound important species that were much in demand for structural applications and were often subjected to dynamic loads. However, in the literature and in the available databases, very little information was available on the vibration properties of these wood species. To solve this problem, three specimens of twenty-four wood species with a cross-section of 10 × 20 mm, with a length of 1600 mm were prepared and subjected to a free vibration test in the fixed support-free configuration. The accelerations as a function of time were obtained. By transforming the recorded accelerations into displacements, it was allowed to determine the logarithmic decrement by mean the first twenty-one amplitudinal peaks. Thanks to the interrelationships, the viscous damping ratio, loss factor, quality factor and specific damping ratio were deduced. The results obtained were relatively variable between species. Compared with the data available in the literature for the same species, there was a considerable difference.

Chemotaxonomic and anatomic wood species identification in bleached pulp: blind test and method validation

Abstract This paper presents a comparative analysis of the blind test outcomes of two independent methods for the identification of tropical wood species in pulp and paper products. Both, the established anatomical and the relatively new chemotaxonomic method support the European Deforestation Regulation 2023/1115 (EUDR), which aims to ensure that only legally harvested timber that has not contributed to deforestation is traded in the EU. The blind test involved 570 decisions on 15 test sheets of 37 self-manufactured mixed tropical hardwood pulps and an industrial beech pulp, used as a matrix. Both detection techniques demonstrated robust performance with over 80 % hit rates. The results show that the synergies and combination of the strengths of both methods can be utilized and lead to even better combined performance. In order to establish the chemotaxonomic identification method as a complement to the conventional anatomy-based method, statistical analyses were performed to assess its intermediate precision between three different GC-MS systems. In most cases, the method gave consistent results independent of the instrument used.

Demystifying the tropics: FTIR characterization of pantropical woods and their α-cellulose extracts for past atmospheric 14C reconstructions

To ensure unbiased tree-ring radiocarbon (14C) results, traditional pretreatments carefully isolate wood cellulose from extractives using organic solvents, among other chemicals. The addition of solvents is laborious, time-consuming, and can increase the risk of carbon contamination. Tropical woods show a high diversity in wood-anatomical and extractive composition, but the necessity of organic-solvent extraction for the 14C dating of these diverse woods remains untested. We applied a chemical treatment that excludes the solvent step on the wood of 8 tropical tree species sampled in South-America and Africa, with different wood-anatomical and extractive properties. We analyzed the success of the extractive removal along with several steps of the α-cellulose extraction procedure using Fourier Transform Infrared (FTIR) spectroscopy and further confirmed the quality of 14C measurements after extraction. The α-cellulose extracts obtained here showed FTIR-spectra free of signals from various extractives and the 14C results on these samples showed reliable results. The chemical method evaluated reduces the technical complexity required to prepare α-cellulose samples for 14C dating, and therefore can bolster global atmospheric 14C applications, especially in the tropics.

Application of principal component analysis (PCA) to the study of the influence of the thermochemical treatment process of tropical wood sawdust on the calorific, mechanical, physicochemical and combustion properties of the resulting fuel briquettes

Despite its potential for environmentally friendly energy production, lignocellulosic biomass has less advantageous physicochemical properties that limit its optimal industrial use. This study used principal component analysis (PCA) to evaluate the effects of two thermochemical processing methods (torrefaction and carbonization) on the calorific, physicochemical, mechanical and combustion properties of the resulting biofuels. Various types of tropical sawdust (Dabema, Dibetou, Fraké, Samba and Iroko) are subjected to these treatments, then densified and characterized for energy applications. Specific fuel consumption varies from Samba torrefied (Sam t: 0.69 kg/L) to Samba carbonized (Sam c: 1.48 kg/L). Higher heating values range from Samba torrefied (Sam t: 23983 kJ/kg) to Iroko torrefied (Iro t: 27,442 kJ/kg). Burning speed varies from Samba carbonized (Sam c: 3.07 g/min) to Iroko torrefied (Iro t: 4 g/min). The impact resistance index ranges from 187.5 to 500% for Dibetou torrefied (Dib t) and Samba carbonized (Sam c), respectively. Densities are between Samba carbonized (Sam c: 297.83 kg/m3) and Dibetou carbonized (Dib c: 393.69 kg/m3). The results indicate that these techniques are promising approaches for improving biomass properties. In sum, the PCA reveals that the effect of treatment type on fuel characteristics also depends on the properties of the initial biomass.

Tropical woods in hydraulic works and marine constructions

Tropical woods in hydraulic works and marine constructions

Effect of slope of grain on mechanical properties of some tropical wood species

ABSTRACT The aim of this work was to study the relationship between the mechanical properties of Cameroonian tropical woods and the slope of grain. The forests of the Cameroonian part of the Congo Basin abound in species that are highly solicited for structural applications. However, little information is available on the influence of the slope of a grain of these wood species. Clear wood specimens of ayous (Triplochiton scleroxylon), azobe (Lophira alata), fraké (Terminalia superbe), okan (Cylicodiscus gabunensis), padouk (Pterocarpus soyauxii), and sapelli (Entandrophragma cylindricum) were prepared. The specimens have a cross section of 20 × 30 mm and a length of 300 mm. These specimens were subjected to a four-point bending test and a double cantilever beam test. Modulus of elasticity (MOE), modulus of rupture (MOR), work at maximum load (WML) and fracture toughness (GIC) were determined. These mechanical properties were calculated for specimens with slopes of grain 0°,15°, 30°,45°,60°, 75° and 90°. The results showed that the slope of grain had significant effects on all the mechanical properties measured on clear wood specimens. MOE, MOR, WML, and GIC decreased with increasing grain slope. On the other hand, azobe and okan absorb much more of the energy that causes microcracking than the other species.

Prediction of the tensile strength of a tropical wood species Terminalia superba assembled by gluing: a comparative intelligent study

ABSTRACT The present study deals with the prediction of the strength of the glue joint stressed in tension on a local wood species called Terminalia Superba (Fraké) assembled according to the bevel configuration using two artificial intelligence models namely ANFIS and LSTM. The experimental data obtained during tensile tests on a tropical species allowed us to determine the mechanical properties taken as structural parameters for the LSTM and ANFIS models. The results of the analysis show that among all the LSTM methods, LSTM ‘ADAM’ offers a low root mean square error (RMSE), a high accuracy (Acc) (RMSE = 2.16, Acc = 0.756). For all methods, ANFIS obtained the best results, a high R-squared and a very low root mean square error (RMSE) (R-squared = 0.979, RMSE = 0.51). This indicates that the prediction of the tensile strength of the adhesive joint is more satisfactory with ANFIS than with LSTM.

Pyrogenic Carbonaceous Materials Production of Four Tropical Wood Produced by Slow Pyrolysis at Different Temperatures: Charcoal and Biochar Properties

Pyrogenic Carbonaceous Materials Production of Four Tropical Wood Produced by Slow Pyrolysis at Different Temperatures: Charcoal and Biochar Properties

Experimental and Numerical Study of the Physico-Hygrothermal Behavior of Two Tropical Wood Species

Experimental and Numerical Study of the Physico-Hygrothermal Behavior of Two Tropical Wood Species

Sensory profile and chemical quality of Merlot aged in barrels of different wood species

The cultivation of Vitis vinifera varieties in Brazil was established in 1970. With the opening of the market to imported labels and a greater variety of wines, viticulture became more competitive, and consumers became more demanding. The aging of wine is a system that involves several reactions based on the extraction of molecules from the wood and also on the micro-oxygenation of beverages. The objective of this study was to investigate the sensorial and chemical evolution of wines aged in barrels of different woods: French oak (Quercus petraea), Amburana (Amburana cearensis), and Jequitibá Rosa (Cariniana legalis). The comparison of the sensorial and chemical characteristics of the aged wine with the non-aged one allowed us to know the modifications resulting from the maturation time. Their distinct evolution among the different species was identified through chromatographic analysis of maturation congeners. Perceived sensory characteristics and acceptance of Brazilian woods were measured using the Napping and UltraFlash Profile methodologies. Tropical woods stood out in terms of acceptance by tasters, and the sensory attributes listed by the panel differ between both.

Physical and mechanical properties of two tropical wood (Detarium macrocarpum and Piptadeniastrum africanum) and their potential as substitutes to traditionally used wood in Cameroon

This study aimed to characterise two little-known woods and discuss their potential to replace those heavily exploited in Cameroon's forests. Amouk (Detarium macrocarpum) and Dabema (Piptadeniastrum africanum) were characterised for their physical and mechanical properties. Density, shrinkage, desorption kinetics, shear strength, tensile strength and modulus of elasticity (MOE) in compression and flexion were determined. A Weibull analysis was performed to predict their failure. It was found that Amouk and Dabéma can be classified as medium-heavy wood with low shrinkage and desorption, following Midilli's empirical model. The physical and mechanical characterisations show that the density, strength and MOE parameters of the woods are close to each other and enable them to be classified as medium-strength woods. The probability of failure in compression follows Weibull's law. These woods can, therefore, be used in structural applications such as construction, replacing common woods.

Charcoal production from four tropical woods through slow pyrolysis under different temperatures: yield of different products and condition of pyrolysis into the reactor

Charcoal production from four tropical woods through slow pyrolysis under different temperatures: yield of different products and condition of pyrolysis into the reactor

Evaluation of Naturally Grown Termite Resistant Tropical Wood Species

Selecting termite resistant wood species for household and construction purposes can guarantee their durability and reduce the pressure on forest resources. The objective of this study was to evaluate the resistance of selected tropical wood species to termite attacks in a natural environment. For this evaluation, 100 wood specimens were cut to 20 cm length, 2.5 cm thickness, and 5 cm width and placed in an open field. Each wood sample was partially inserted into the ground to a depth of 10 cm, and the remaining part was kept above the ground for visibility and handling purposes during the sampling period. Wood density analyses were simultaneously carried out in the laboratory using wood specimens of equal length (2 cm), thickness (2 cm), and width (2 cm). The results indicated that species such as Terminalia superba and Hallea ciliata had the highest mean weight loss of 57.62% and 30.27%, respectively, and were highly susceptible to termite attacks compared to Terminalia ivorensis, Lophira alata, and Heritiera utilis, which were very resistant with only mean weight losses of 0.29%, 0.78%, and 0.81%, respectively. Some wood species, such as Terminalia superba, Piptadeniastrum africanum, Terminalia ivorensis, and Hallea ciliata exhibited low density, whereas Lophira alata, Nauclea diderrichii, and Tetraberlinia tubmaniana displayed high density. A significant correlation (r = -0.79, p &lt; 0.001) was observed between the weight loss and the density of the selected wood species. It was noted that variations in termite resistance were primarily attributed to wood density.

Measurement of the Dielectric Properties of Tropical Wood Species for Application to Millimetre‐Band Antennas

Measurement of the Dielectric Properties of Tropical Wood Species for Application to Millimetre‐Band Antennas