Effects of termal treatment on the physical properties of Buchenavia sp. (branquilho) wood

This work aimed to evaluate the effect of heat treatment on the physical properties of wood from Buchenavia sp. The heat treatments were carried out at temperatures of 180 °C and 200 °C for 2 h. Apparent density (AD), basic density (BD), porosity (Ф), mass loss, longitudinal (LS), radial (RS), tangential (TS) and volumetric (VS) shrinkages and anisotropic factor (AF) were determined. The lowest values of basic density (0.67 g cm-3), apparent density (0.77 gcm-3), and porosity (43.3%) were observed for the wood treated at a temperature of 200 °C. Mass losses increased with increasing temperature and the highest values were observed under the condition of 200 °C (9.3%). The LS and AF was not affected by heat treatments. The mean values for RS (3.1%), TS (5.1%), and VS (9.1%) were reduced after the performance of heat treatments at temperatures of 180°C and 200°C, which did not differ from each other. The thermal treatments were able to reduce the dimensional instability of Buchenavia sp. Thermal treatments enhance the use of less prestigious Amazonian woods in the civil construction market.

Physicomechanical characterization and wood machining from 10 12-year-old Hevea progeny clones with potential for furniture

The objective of this work was to evaluate the physical, mechanical, and wood machining properties of 10 clonal progenies with 12 years of age aiming to produce furniture. A total of 10 progenies and three trees per progenies were used, totalling 30 trees analyzed. The basic density ranged from 0.404 g.cm-3 (IAC 301) to 0.495 g.cm-3 (IAC 326), being it considered a light wood. The anisotropy coefficient values ranged from 1.05 (IAC 40) to 1.68 (PB 330) considered low to medium dimensional instability allowing the use of wood to produce furniture with low dimensional movements. In the compression test most clones fall under class C30. For MOR and MOE, it was observed greater values for IAC 326 (11666 MPa) and GT1 (9575 MPa). In wood machining tests, slightly raised large and few defects on the surface, being them considered easy to work. The results obtained for Hevea brasiliensis, 12 years old, allow us to affirm that wood from a younger age is an alternative for furniture production and will consequently contribute to the reduction of the exploitation and degradation of native forests in Brazil for this purpose.

THE IMPORTANCE OF USING MULTIPLE ANALYSES TECHNIQUES TO DETERMINE THE PHYSICAL CONDITION OF THE WATERLOGGED WOOD NEAR THE CORRODED PARTS

In this study, three samples taken from the planks of the Yenikapı 29 shipwreck were analysed. Firstly, the maximum water content (MWC) and basic density values of the samples were calculated. MWC of the IK13-1 was 164% and the MWC of the SK6-1 was 87%. Because of these low MWC values, samples could be classified as non-degraded. When the SEM images of these two samples were examined, it was understood that the IK13-1 sample was non-degraded but the SK6-1 sample was penetrated with corrosion product and could not be classified as non-degraded. With these analyses, the XRF method was used to measure the iron amounts of the samples. The iron amount of the SK6-1 was 32.3% and the corrosion accumulation in this sample was also proved with XRF. In order to avoid incorrect results, multiple analysis techniques should be used for determining the physical condition of the waterlogged wood near the corroded parts.

Effect of Perforation Dyeing Technique on Color Difference, Colorfastness, and Basic Density of Living Red-Heart Chinese Fir

Red-heart Chinese fir is an excellent geographic provenance of Cunninghamia lanceolata, with high-value red heartwood. However, the formation of red heartwood is usually slow. To quickly cultivate red-heart Chinese fir, we studied perforation dyeing technology on living trees that were 7 years old and efficient in high-value red heartwood formation. Reactive dye (%), penetrant (%), KH2PO4 (%), and pH were selected as influencing factors, and an orthogonal test (L9(3)4) was used. The results showed that the total color difference between the experimental and CK groups ranged from 13.74 to 26.86 NBS, which was a significant visual perception (above 12 NBS). The total color difference before and after soaking in water for 6 h ranged from 2.30 to 5.12 NBS, which belonged to the detectable and identifiable value of the human eye (2~5 NBS). After the injection of the dye liquid, the wood basic density (WBD) was significantly affected after one year. After a comprehensive analysis of wood color difference, colorfastness, and WBD of the orthogonal test, the best dyeing process of juvenile red-heart Chinese fir was reactive dye: 0.8%, penetrant: 0.05%, KH2PO4: 0.3%, and pH: 3.5. The results of this study can provide a reference to improve the value of red-heart Chinese fir, a fast-cultivated, high-value decorative wood material.

PHYSICAL, CHEMICAL AND MORPHOLOGICAL CHARACTERISTICS OF BAMBOO SPECIES GUADUA TRINII AND GUADUA ANGUSTIFOLIA AND THEIR POTENTIAL TO PRODUCE HIGH-VALUE PRODUCTS

High-value products can be obtained from non-traditional lignocellulosic resources, such as bamboo, taking full advantage of these materials through efficient, low-cost and low-pollution fractionation processes. This work aims to analyze the physical, chemical, and morphological differences between two bamboo species as a rapidly growing resource of great regional interest – Guadua trinii and Guadua angustifolia. Both samples were characterized in terms of basic density, morphological characteristics, and chemical composition. This work shows that G. trinii has a significantly denser woody structure, with a uniform density at the sampled culm height. The internal structure consists of a parenchyma matrix and vascular bundles composed of parenchyma cells and fiber bundles. G. angustifolia has significantly longer fibers. Chemical characterization showed differences between the carbohydrate and lignin contents. The results of this work are critical to know the potential of both bamboo species as a source of high-value products in the bamboo biorefinery framework.

Conventional Low-density Particleboards Produced With Particles From Mauritia Flexuosa and Eucalyptus Spp. Wood

The use of alternative raw materials to produce particleboards is an interesting strategy to add value to lignocellulosic biomass and diversify the forest products industry. The aim of this study was to evaluate the potential for using Mauritia flexuosa particles in association with Eucalyptus spp. wood for the production of particleboards. Prior to the production of the panels, the raw materials were evaluated for basic density and chemical composition. The panels were produced with particles of Eucalyptus spp. and Mauritia flexuosa in mass proportions of 100/0%, 90/10%, 80/20%, 70/30% and 60/40%, respectively. The quality of the particleboards was evaluated by water absorption and thickness swelling, internal bonding and static bending tests. As Eucalyptus spp. particles were replaced by Mauritia flexuosa, the panels showed less dimensional stability, due to the fact that the compression ratio increased due to the lower density of Mauritia flexuosa particles. The substitution of 1% of Mauritia flexuosa particles caused a reduction of 10.49 MPa for MOE, 0.09 MPa for MOR and 0.01 MPa for internal bonding. The results demonstrate that it is feasible to replace up to 17.5% of Eucalyptus spp. wood with particles from Mauritia flexuosa so that the panels have physical and mechanical properties appropriate to the marketing standards.

Anatomical and chemical characterization of Alstonia boonei for pulp and paper production

Alstonia boonei, an abundant lesser utilized species within the West African Subregion, was evaluated as an alternative raw material for pulp and paper production. The basic density (BD), fibre characteristics [fibre length (FL), fibre diameter (FD), lumen diameter (LD) and wall thickness (WT)], derived anatomical indices [Flexibility Ratio (FR), Slenderness Ratio (SR), Rigidity Coefficient (RC), Luce’s Shape Factor (LSF), Solids Factor (SF) and Runkel Ratio (RR)] and chemical composition (lignin, holocellulose, 1% NaOH solubility and ash contents) of A. boonei were studied to evaluate variation along the trunk (base, middle and top portions) and ascertain its suitability for pulp and paper production. Significant variations were observed in the density and fibre characteristics along the trunk of the tree. Although the FD was large, the observed adequate FL, thin-wall and large LD implied easy beating of fibres and manufacture of dense, smooth and strong papers. The favourable SF, RR, FR, RC, and LSF values obtained for the fibres would produce papers with suitable burst and tearing strengths and folding endurance. Chemically the lower lignin (< 30%), ash and 1% NaOH solubility and the high holocellulose contents of A. boonei, will generate a higher pulp yield. A. boonei although a low-density species, will be desirable for pulp and paper production.

Genomic studies with pre-selected markers reveal dominance effects influencing growth traits in Eucalyptus nitens

Genomic selection (GS) is being increasingly adopted by the tree breeding community. Most of the GS studies in trees are focused on estimating additive genetic effects. Exploiting the dominance effects offers additional opportunities to improve genetic gain. To detect dominance effects, trait relevant markers may be important compared to non-selected markers. Here we used pre-selected markers to study the dominance effects in a Eucalyptus nitens (E. nitens) breeding population consisting of open-pollinated (OP) and controlled-pollinated (CP) families. We used 8221 trees from six progeny trials in this study. Of these, 868 progeny and 255 parents were genotyped with the E. nitens marker panel. Three traits; diameter at breast height (DBH), wood basic density (DEN) and kraft pulp yield (KPY) were analysed. Two types of genomic relationship matrices based on identity-by-state (IBS) and identity-by-descent (IBD) were tested. Performance of the genomic best linear unbiased prediction (GBLUP) models with IBS and IBD matrices were compared with pedigree-based additive best linear unbiased prediction (ABLUP) models with and without the pedigree reconstruction. Similarly, the performance of the single-step GBLUP (ssGBLUP) with IBS and IBD matrices were compared with ABLUP models using all 8221 trees. Significant dominance effects were observed with the GBLUP-AD model for DBH. The predictive ability of DBH is higher with the GBLUP-AD model compared to other models. Similarly, the prediction accuracy of genotypic values is higher with GBLUP-AD compared to the GBLUP-A model. Among the two GBLUP models (IBS and IBD), no differences were observed in predictive abilities and prediction accuracies. While the estimates of predictive ability with additive effects were similar among all four models, prediction accuracies of ABLUP were lower than the GBLUP models. The prediction accuracy of ssGBLUP-IBD is higher than the other three models while the theoretical accuracy of ssGBLUP-IBS is consistently higher than the other three models across all three groups tested (parents, genotyped, non-genotyped). Significant inbreeding depression was observed for DBH and KPY. While there is a linear relationship between inbreeding and DBH, the relationship between inbreeding and KPY is non-linear and quadratic. These results indicate that the inbreeding depression of DBH is mainly due to directional dominance while in KPY it may be due to epistasis. Inbreeding depression may be the main source of the observed dominance effects in DBH. The significant dominance effect observed for DBH may be used to select complementary parents to improve the genetic merit of the progeny in E. nitens.

Modeling of radial variations of wood properties in naturally regenerated trees of Betula platyphylla grown in Selenge, Mongolia

Wood properties, such as annual ring width, wood fiber length, vessel element length, basic density, air-dry density, dynamic Young’s modulus, modulus of elasticity (MOE), modulus of rupture (MOR), absorbed energy in impact bending, compressive strength parallel to grain, and shearing strength, were investigated for wood from 10 naturally regenerated trees of Betula platyphylla Sukaczev in Mandal, Selenge, Mongolia. Mixed-effects models were used to evaluate the radial variations in the wood properties. The mean values of wood properties obtained in the present study were in almost the same range, with a few exceptions, as those reported by other researchers for other Betula species. The radial variations of wood properties in B. platyphylla were well-fitted to a nonlinear mixed-effects model (logarithmic formula); all examined wood properties increased from the pith and then became constant toward the bark side. The wood properties significantly differed between the core and outer wood. Basic density, air-dry density, and dynamic Young’s modulus were significantly correlated with MOE, MOR, and compressive strength. It is concluded that when the wood of B. platyphylla is utilized as raw materials for solid wood products, the differences between the core wood and outer wood should be considered. In addition, the selection of wood with higher strength properties can be achieved using the wood density and dynamic Young’s modulus as indicators.

DAMAGE BY DEFOLIATING INSECTS AND ITS EFFECT ON THE QUALITY OF WOOD FOR CHARCOAL PRODUCTION

The objective of the present work has been to evaluate the impact of damage caused by defoliating insects on wood quality and charcoal production, and to quantify the losses per hectare according to the charcoal produced. Seven-year-old Eucalyptus grandis × Eucalyptus urophylla (clone A) and Eucalyptus saligna (clone B) trees, both in healthy condition and damaged by defoliating insects, were selected, with five trees to be used per treatment. Wood disks were removed from the trees at 0, 25, 50, 75 and 100% of the commercial height for analyzing the properties of the wood and for preparing and characterizing the charcoal. Damage by defoliating insects decreased the basic density of the trees at all axial positions by up to 23 kg m-3. Also, the extractives and lignin contents increased, while the holocellulose content decreased in the attacked plants. Changes in the wood characteristics led to increased fixed carbon content and gravimetric yield, and a decrease in density. The charcoal productivity from the plants damaged by defoliating insects was lower, mainly because of the decrease in volumetric production.