Volume 78, Issue 9

The control authorities of timber trade lack quick and easy methods to verify the legality of the traded product. This includes the clear identification of the timber species. In this study, a simple genetic method, the macroarray technique, was modified and optimised for this purpose. The internal transcribed spacer (ITS) was used as barcode region. Specific probes were designed and tested using this barcode of trade-relevant, CITES protected wood species and their look-alikes. The results reveal that 61 of these probes are suitable for identification purposes. Hence, 32 of the 50 investigated species can be clearly identified using the developed macroarray. Additional 15 species are represented by probes in groups of two to three species, which enables a delimitation of the species present. For four species, no identification was possible applying the probes created. The findings indicate the potential of time and cost savings compared to currently established methods in species control in the timber trade.

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.

The anatomical description of wood and charcoal for a wide variety of purposes is an essential tool for compiling databases to correctly identify species. This study describes and compares the anatomy of the wood and charcoal of Manilkara sp., collected in a protected area in the Pará state, Brazil. The qualitative anatomical characteristics of the wood, such as diffuse-porosity; vessels in radial multiples; alternate intervessel pits; axial parenchyma in lines or reticulate; rays uniseriate or biseriate, not storied, are corroborated in the literature. Moreover, this work reports the presence of helical thickenings in the vessel elements and possible helical thickenings in fibres in Manilkara . After the carbonization process, there were morphometric changes in the anatomical elements, as an increase in vessel frequency between 23 % and 141 %, and in ray frequency between 2.8 % and 12.9 %; while ray height decreased and ray width increased. Overall, some anatomical variations could be related to, or a result of the interaction between species plasticity, genetics, age and environmental factors. These characteristics enabled the identification of the samples at the genus level and the anatomical description of the wood and charcoal can be useful for forest inspections.

The aim of this study was to reveal the strength mechanism of the mortise-and-tenon (M–T) joint at a deeper level. The effects of tenon fit on bending and withdrawal load resistances, and strain distributions outside and inside beech ( Fagus sylvatica ) wooden round-end M–T joints were experimentally investigated using mechanical testing synchronizing digital image correlation method (DICM). The results showed that (1) the tenon fit had greater significance on withdrawal properties than that of bending properties of M–T joints; (2) the bending load resistance was linearly proportional to withdrawal load resistance based on both theoretic analysis and regression methods; (3) strain distributions outside M–T joints during the loading process were not sufficient to evaluate the mechanical behaviors of the M–T joint; (4) strain distributions inside M–T joints showed that the maximum strains on top and bottom parts of the tenon were significantly greater than that of middle part, but the difference decreased with the growth of tenon fit; (5) the method of determining the optimal tenon fit of the M–T joint based on the DICM was proposed, and optimal tenon fit of beech wooden round-end M–T joint evaluated ranged from 0.4 to 0.5 mm.

Pernambuco is the archetypal wood in modern bows of the violin-family. This species ( Paubrasilia echinata ) is endangered. Existing literature suggests remaining questions on how its properties’ variability relates to qualification in bow-making, and to diversity. Here 61 pernambuco specimens, with various qualitative evaluations by makers, are characterised for physical, elastic, dynamic, and optical properties. Results are compared with standard relations between-properties, and with 53 pre-selected tropical hardwoods. The tested pernambuco stands in the medium-upper range of these pre-selected species for density ( ρ ) and modulus of elasticity ( E ). It is exceptional for its very low damping coefficient (tan δ ) and very intense colour (red a* , yellow b* and chroma C* ). Within-species variability is high. Qualification is mostly associated to ρ , colour hue angle h ° and gloss, then to elasticity – but E and E/ρ (specific modulus) overlap between groups. Qualification involves appearance ( L* , h °, gloss) when freshly cut, and with anticipation of changes after ageing or finishing. The properties (damping, chroma) that make pernambuco exceptional among species, are not clearly related to the qualification within the studied sampling. Analyses help better understand the specificities of pernambuco, and highlight the multifactorial nature of wood selection at two levels: between-species preference, and within-species qualification.