Wood Species Research Articles

Adhesion strength and pendulum hardness of some coatings in wood heat-treated by different methods

Beech (Fagus sylvatica L.) and pine (Pinus sylvestris L.) wood specimens were heat-treated separately at three different temperatures (170 °C, 190 °C, and 210 °C) with steam treatment method (STM), oil treatment method (OTM), and hot-air treatment method (HTM). Then, the specimen surfaces were coated with water-based, polyurethane-based, and oil-based varnishes according to industrial applications. The study results show that both hardness and adhesion strength values of STM and HTM treated specimens were similar for both wood species. In contrast, these values were generally lower in OTM-treated specimens. For all applied methods, heat treatment temperature had no significant effect on hardness values. Varnish adhesion strength decreased in all heat-treated wood specimens compared to untreated specimens. Adhesion strength also decreased in STM- and HTM-treated specimens with increasing heat treatment temperature. Hardness values increased in all specimens coated with polyurethane- and water-based varnish compared to the specimens without varnish. However, hardness decreased in the specimens coated with oil-based varnish. In contrast, the highest adhesion resistance was determined in the specimens coated with oil-based varnish under all heat treatment conditions. In addition, the heat treatment method is more effective relative to the hardness values and the treatment temperature is more effective relative to the adhesion strength of varnished pine and beech specimens.

Comparison of physico-chemical and thermo-mechanical properties of sungkai (Peronema canescens Jack.), sengon (Falcataria moluccana (Miq.) Barneby & J.W. Grimes), and teak (Tectona grandis L.f.) wood veneers

ABSTRACT Sungkai (Peronema canescens Jack.), sengon (Falcataria moluccana (Miq.) Barneby & J.W. Grimes), and teak (Tectona grandis L.f.) are some of the main fast-growing species in Indonesia. Limited research data on the physicochemical and thermo-mechanical properties of these wood species represents a significant drawback for their enhanced industrial utilization. This study aimed to evaluate the properties of these three kinds of wood according to their colour by applying the CIELab colour measuring system, chemical composition by Fourier-transform Infrared Spectroscopy (FTIR), and Pyrolysis–gas Chromatography–Mass Spectrometry (Py-GC/MS) analyses, and the thermo-mechanical properties by Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA). The higher colour quantification (E*) value indicated brighter wood having higher carbohydrate and lower lignin content according to Py-GC/MS results. Besides, the colour may be attributed to the higher phenolic and extractive content. The order of woods from the highest to the lowest phenolic content was teak > sengon > sungkai. Meanwhile, DMA analysis revealed that sungkai had the highest storage modulus, followed by teak and sengon. The findings of this study suggested that the properties of wood could be predicted based on its colour appearance, which could be used in industrial applications for rapid identification of wood properties.

Experimentation of a PVA-Borax hydrogel for the removal of Paraloid B72® from artifacts of archaeological interest from the National Archaeological Museum in Naples, Italy

This paper shows the results of an experimentation aimed at the removal of a polymeric film of aged Paraloid B72® originally placed to protect some wooden artifacts belonging to the Egyptian collection of the National Archaeological Museum of Naples (MANN). The study was conducted on two shabtis dated to the 19th Dynasty and a sculpture of Ptah-Sokar-Osiris dating to the late period. Thanks to the collaboration between the National Archaeological Museum of Naples and the Laboratory of Restoration of Wooden Artifacts of the University of Naples Suor Orsola Benincasa, it was possible to conduct an in-depth study of the artifacts, from both an archaeological-historical point of view and from a conservation point of view. This led to the development of the above-mentioned experimentation and to the planning of a proper restoration intervention. The study and experimentation were supported by several diagnostic techniques. In a first stage, non-invasive investigations were carried out to study the execution technique and the state of conservation of the artifacts. This allowed the recognition of the wood species that constituted the three sculptures through optical microscopy, whereas IR reflectography, UV induced fluorescence and X-ray radiation (XRF) were conducted to identify the type and the chemical nature of the pigments. Based on the above analysis, different restoration strategies, based on the removal of Paraloid B72® through a methodology that would act in full respect of the wooden support of the artifacts, were considered. Pros and cons of the different methodologies applied in the recent past for the removal of aged Paraloid from artifact surfaces were analysed. A removal technique based on the use PVA-Borax hydrogel loaded with a solvent mixture was selected. Experiments were conducted to validate the effectiveness of the selected method.

An evaluation of the antimicrobial activity of some commonly used wood species

Aims: Antibiotic resistance mechanisms in pathogenic bacteria constitute an important obstacle in the fight against infection. Controlling the spread of resistant pathogens by utilizing antimicrobial activity on their surfaces may help us in this fight. There are many plant and wood species that have been previously tested for their antibacterial and antiviral properties. In this study, walnut (Juglans regia), white mulberry (Morus alba), white oak (Quercus alba), yellow pine (Pinus sylvestris), and beech (Fagus sylvetica), which are among the wood species used in the production of products that are in constant contact with humans in daily life, such as furniture, doors, and beads, were examined in terms of an antistaphylococcal effect. Methods: Five groups of tree species and glass samples selected as a positive control were cut into 1 cm3, contaminated with Staphylococcus aureus solution with a concentration of 1*106 CFU/ml, and monitored for five days. Each day, five randomly selected samples from each group were sonicated with phosphate buffered saline. Samples taken from the sonicated solution were cultured on tryptic soy agar, and the number of bacteria per sample was calculated. One sample selected from the uncontaminated samples was incubated with 0.5 McFarland standard bacterial solution on Müller Hinton agar, and the diameter of inhibition was evaluated. The study was repeated twice. The significance level was set at 0.05. Results: The agar diffusion method showed inhibition zone only in Q. alba and M. alba. In samples contaminated with bacteria, the highest antistaphylococcal effect was found in Q. alba. This was followed by M. alba, P. sylvestris, F. sylvetica. There was no significant difference between J. regia and the positive control. Conclusion: In this study in which we wanted to emphasize the importance of the antimicrobial activity of surfaces for pathogens known to live on the surface environment, all trees except J. regia showed antistaphylococcal activity. It is thought that the procyanidins?phenethyl, benzyl, and benzyl?in the bark of the trees are effective. In previous studies, Q. alba in particular is recommended for anti-infective use due to its high inhibition effect. Antibacterial activity was also found in F. sylvetica, which is known to have antiviral activity. Antibacterial activity was not demonstrated for J. regia. In order to prevent the spread of infection in collective living areas, it is recommended that trees be selected that contain antimicrobial raw materials such as M. alba, Q. alba, P. Sylvestris, and F. sylvetica and to evaluate the use of extracts from these trees as natural and edible products to combat bacteria.

Design of selected wood species for longer span trusses

The trends of researches in the built industry are exploration of the available alternatives; either as raw materials or finished products construction materials, to most construction materials that have been playing dominant roles in construction industry for decades. Aside that the cost of using them in construction keep rising, the associated health hazards in their production and usage are huge and costly to rectify. The usage of locally available construction materials is being hindered by the lack of useful engineering data of the materials for structural design. Wood is an alternative local, green and sustainable material to steel in roof truss design and construction. Its usage has been limited to short span roof trusses based on inherited knowledge especially in Africa. There is need to know the actual capacity and potential of various wood species in relation to roof design. This work studied the properties of; Gmelina arborea, Tectona grandis (Teak), Terminalia superba (Afara), Ayin (Anogeissus leiocarpus), and Acacia (Robinia pseudoacacia). The values obtained from the laboratory experiments conducted on them were used to design rafter and tie beam of king post roof truss spanned to 12 m and 8 m using timber section 0f 50 mm x 150 mm of all the species. Then section sizes of 150 mm x 250 mm and 250 mm x 350 mm of Acacia were then designed separately. It was found that the five species were not suitable for long span roofing using the chosen three section sizes because the tie beams failed in deflection, which is most critical to deliver a safe, durable and serviceable roof. However, all the species, except Afara, are satisfactory for rafter whose span is not more than 7.5 m. It was also discovered that the higher the section size of timber used in the design the lower the deflection.

Extraction and Characterization of Acidolysis Lignin from Turkey Oak (Quercus cerris L.) and Eucalypt (Eucalyptus camaldulensis Dehnh.) Wood from Population Stands in Italy.

Acidolysis lignins from the species Quercus cerris L. and Eucalyptus camaldulensis Dehnh. were isolated and characterized using high pressure size exclusion chromatography (HP-SEC), Fourier-transform (FTIR) infrared spectroscopy, analytical pyrolysis-gas chromatography-mass spectrometry (Py-GCMS), and two-dimensional heteronuclear single quantum coherence (2D HSQC) NMR spectroscopy. The acidolysis lignins from the two different species varied in chemical composition and structural characteristics, with Q. cerris L. lignin having a higher S/G ratio and higher molar mass averages with a bimodal molar mass distribution. The different analytical techniques FTIR spectroscopy, Py-GCMS, and 2D NMR spectroscopy provided consistent results regarding the S/G ratio of the lignins from the two wood species. Based on the determined high S/G ratio of both oak and eucalypt lignin, the two wood sources could be promoted as substrates for efficient lignin isolation in modern forest biorefineries in order to develop innovative lignin-based value-added biorefinery products.

Termites infestation on different Eucalyptus wood species and control using natural oil from plants

Termites infestation on different Eucalyptus wood species and control using natural oil from plants

Timber Structures of Florence Cathedral: Wood Species Identification, Technological Implications and Their Forest Origin

The Cathedral of Florence is one of the largest churches in the world and is known for one of the most famous domes ever, which characterizes the skyline of the city. The dimensions of the building mean that the dimensions of the roof are equally large and so are the wooden structures that support it. The roof of the cathedral is organized on two levels: the roof of the large central nave and, at a lower level, those of the two lateral naves. The purpose of this paper is the identification of the wood species of which the structures are made. The sampling method of the 408 samples that have been identified is then described, the methods followed to reach a reliable identification and finally the results. The timbers most represented among the structural elements are those of silver fir, chestnut and elm. Other timbers are then found in the other components less directly linked to the main structural parts that make up the trusses. The paper then discusses the technological implications on the use of those woods within the wooden covering structures of the cathedral and the main sources of timber that the builders had available, in particular the Casentino forests that the Municipality of Florence had donated to the structure that managed the construction of the cathedral (Opera di Santa Maria del Fiore—OPA). OPA still exists today and is responsible for the maintenance of the cathedral and other annexed buildings.

Effect of silane-siloxane based water-repellent impregnant on the dimensional stability of some wood species

A silane-siloxane based water-repellent substance (S-WR) was used as an impregnation material for Scots pine (Pinus sylvestris L.), black pine (Pinus nigra Arnold), sessile oak (Quercus petraea Liebl.), and cedar (Cedrus libani A. Rich). In the impregnation process, the immersion method was carried out for various periods (30 min, 3 h, and 24 h). Following impregnation, physical properties of the wood (retention, contraction, expansion, water intake rate, specific gravity, etc.) were determined. The retention was highest in sessile oak wood (0.96%) and lowest in black pine wood (0.24%). The highest specific gravity value was found in stemless oak (0.86 g/cm³) impregnated for 24 h, and the lowest air-dry specific gravity value was found in Scots pine (0.40 g/cm³) impregnated for 30 minutes Absolutely dry (0% humidity) specific gravity was highest in sessile oak for 24 h (0.83 g/cm³). Shrinkage was highest in the sessile oak control sample (13.5%). The expansion amount was highest in the cedar wood control sample (17.5%) and lowest in sessile oak wood (1.66%). The highest water uptake rate (SAO) was determined in Scots pine wood at 96 h (105%), and the lowest in sessile oak wood in 24 h (8.80%). In summary, silane-siloxane based water-repellent impregnation material was found to be effective in providing dimensional stability in wood.

Sustainable and Secure Transport: Achieving Environmental Impact Reductions by Optimizing Pallet-Package Strength Interactions during Transport

Increasing quantities of products are being transported across widely distributed supply networks; the sustainability of the packaging used to transport these goods, or unit loads, presents an area of potential concern. The most common type of unit load in the U.S. is wooden pallets supporting various configurations of stacked corrugated boxes. Research into unit load cost optimization revealed that increasing the stiffness of a pallet’s top deck can significantly affect the strength of the assembled, stacked corrugated boxes and provides opportunities to reduce the board grade required for accompanying corrugated boxes. However, there remains a knowledge gap regarding the environmental implications of this type of unit load optimization method. To address this, we conducted a life cycle analysis (LCA) to investigate the environmental implications of optimizing a unit load using this method. The environmental impacts of paired (pallet and box) unit load design scenarios (n = 108) were investigated using varied wood species, pallet top deck thicknesses, corrugated boxes sizes, corrugated flutes, and board grades. Initial and optimized unit load scenarios ensured that the unit loads offered equivalent performance. LCA results indicate that optimizing the unit load can reduce environmental impacts by up to 23%, with benefits accruing across most impact categories primarily due to the reduction in corrugated material used. Ozone depletion, the exception, was mainly affected by the increase in the amount of required pallet materials. This study provides minimum required conditions as preliminary guidance for determining the usefulness of unit load specific analysis, and a sensitivity analysis confirmed these values remain unchanged even with different transportation distances. Through the unit load optimization method, this study demonstrates that an effective way to reduce the overall environmental impact and cost of transported unit loads involves increasing the stiffness of the top decks and reducing the corrugated board grade.

Microwave Treatments and Their Effects on Selected Properties of Portuguese Pinus pinaster Aiton. and Eucalyptus globulus Labill. Wood

The most widespread wood species in the Portuguese forest and the most widely utilized are maritime pine (Pinus pinaster) and eucalyptus (Eucalyptus globulus Labill). In the case of eucalyptus, except for the pulping sector, it might have limited usage due to drying issues and low permeability. Microwave (MW) treatment is a technology that has been used to improve wood species’ permeability. Therefore, the present paper aimed to evaluate the MW treatment of both Portuguese wood species and to investigate the effects of different MW treatments on wood’s density, water uptake capability, modulus of rupture (MOR), and modulus of elasticity (MOE). Using small clear wood specimens, two MW powers were used, 700 and 1200 W, and the samples were submitted to successive MW cycles of 2 min till they reached the required dryness. The results showed that each wood species had a different behavior during the MW drying in terms of drying rate, supply, and consumption of energy. In general, with the increase in MW power, the densities of both species decreased and the water uptake increased, as a possible indicator that a certain level of microstructural damage might have occurred. Regarding the mechanical properties of MW-treated maritime pine and eucalyptus wood specimens, under the harshest conditions (MW power of 1200 W), MOR and MOE were reduced compared with the wood sample without MW treatment.

Inventaritation and Potential Utilization of Macroscopic Mushroom in TPKh Tenjo KPH Bogor

The TPKh Tenjo KPH Bogor is a production forest wood collection area and becomes a production forest for the Acacia mangium wood species. Timber harvesting activities leave a lot of tree stumps, twigs, or piles of wood that do not pass production. Environmental conditions with a lot of harvested wood residue and supported by relatively cool air temperatures and high humidity, it is suspected this area has a diversity of macroscopic fungi with various unknown potentials. This study aims to obtain data on the types of macroscopic fungi and their potential uses. The research method includes the stages of exploration, identification and literature study to obtain the potential of the macroscopic fungi found. The research succeeded in finding 8 types of macroscopic fungi classified into the phylum Basidiomycota, 3 orders, 5 families, and 7 genera. The macroscopic fungi include Coprinellus sp., Lentinus sp., Panus sp., Schizophyllum commune, Pycnoporus sp., Fomitopsis sp. 1, Fomitopsis sp. 2, and Lycoperdon sp. Based on the results of the literature study, the potential uses of macroscopic fungi were found are as food, medicine, natural pigment producer, and enzyme producer. This data report can be used as basic information on the use of macroscopic mushrooms by communities around the area to be used as food or medicinal ingredients. Further utilization of this data is the development of the potential of macroscopic fungi that produce enzymes, pigments or drugs to be produced on a large scale. Research on the development of potential mushroom conservation strategies can also be carried out for sustainable use.

Assessing the Versatility of Bioextraction to Preserve Waterlogged Wood

An innovative bio method was investigated to extract harmful iron and sulfur species from waterlogged wood samples. The method was compared with a chemical treatment. Both approaches were applied on lacustrine and marine samples, from different wood genera, to evaluate the versatility of the proposed bio method. Non-invasive and non-destructive methods were carried out to investigate both bio-based and chemical treatments. The result was that some wood genera were more affected by the bio approach, with a clear distinction between lacustrine beech and pine against oak and lime wood species. The chemical approach showed potential harm for the wooden structure, with acidic pH values and an increase of maximum water content, both implying degradation of the wood structure. In terms of extraction, no iron or sulfur products were detected by Raman spectroscopy on biologically treated samples, in agreement with extraction rates calculated. It was also suggested that iron bonded to wood was extracted with the chemical approach, and calcium content affected by both approaches.

Simultaneous Improvement of Surface Wettability and UV Resistance of Wood with Lignin-Based Treatments.

Recent advancements in wood modification aim to enhance the inherent qualities of this versatile biological material, which includes renewability, ease of processing, and thermal insulation. This study focuses on evaluating the effectiveness of lignin as a protective agent for less durable wood species, namely, Pinus nigra and Fagus sylvatica L. The impregnation of wood with three various forms of lignin, such as kraft lignin, acetylated kraft lignin, and lignin nanoparticles, was carried out using the vacuum technique at room conditions. The results showed that the treatments significantly improve the hydrophobicity of wood surfaces, particularly in pine wood, and provide protection against UV ageing. Additionally, the treatments contributed to the stabilisation of moisture content at different humidity levels. Although slight colour variations were observed, their impact on the visual appearance was minimal, and the thermal analysis confirmed enhanced thermal properties. Additionally, plasma treatment further enhanced hydrophobicity after treatments, offering potential benefits in terms of moisture resistance and durability. The findings of this study highlight the promising effects of lignin-based treatments on wood properties, providing sustainable solutions for wood protection in various sectors. However, further optimisation is needed to fully explore the potential of lignin and lignin nanoparticles.

Wood Utilization in Windmill Mechanisms on Sikinos Island (Greece)

Windmills constitute a valuable part of cultural heritage, especially in Greece, as unique structures of popular architecture and know-how of the pre-industrial era. Their wooden mechanisms were of exceptional constructional ingenuity, with the Mediterranean ones bearing a vertical wing and a rotating roof (“trula”), with a manual torsion mechanism that allowed for operation in all wind directions. Sikinos is a small Aegean island characterized by rich landscapes, which do not have wood-producing forests, but only sparse Juniperus phoenicea shrub land mixed with evergreen hardwood species and the presence of numerous sclerophyllus vegetation species (maquis). Three abandoned windmills are still preserved on the island today, but only two of them appear to have their wooden mechanisms left. In the one windmill mechanism examined, it was found that different wood species were used to manufacture its individual parts. Oak wood was used in most of the large elements, with the exception of the sprattle beam (“zigos”), which is made of fir wood. The local juniper was not used in any crucial part of the mechanism, though it was used only as a structural material on the first floor (“anogio”) flooring, along with large-diameter olive trunks. The findings of this study highlighted the thorough knowledge of the properties of various wood species and the effective use of simple tools toward the construction of functional and effective windmill mechanisms.

Comparative study of four timber wood species in southern Mali (West Africa) by combining FTIR spectroscopy and multivariate analysis

Comparative study of four timber wood species in southern Mali (West Africa) by combining FTIR spectroscopy and multivariate analysis

Cadmium up Taking and Allocation in Wood Species Associated to Cacao Agroforestry Systems and Its Potential Role for Phytoextraction.

Trees in cacao Agroforestry systems (AFS) may present a high potential for cadmium (Cd) phytoextraction, helping to reduce Cd in cacao (Theobroma cacao L.) plants grown in contaminated soils. To assess this potential, four forest fine-woody species commonly found in cacao high-productive sites in Colombia (Tabebuia rosea, Terminalia superba, Albizia guachapele, and Cariniana pyriformis) were exposed to contrasting CdCl2 contamination levels (0, 6, and 12 ppm) on a hydroponic medium. Growth dynamics, tolerance index (TI), and Cd concentration and allocation in leaves, stems, and roots were evaluated for up to 90 days after initial exposure. T. superba, A. guachapele, and C. pyriformis were classified as moderately tolerant (TI > 0.6), and T. rosea was considered a sensitive species (TI < 0.35) under 12 ppm Cd contamination. Despite showing a high stem Cd concentration, C. pyriformis also showed the lowest relative growth rate. Among the evaluated forest species, A. guachapele exhibited the highest Cd accumulation capacity per plant (2.02 mg plant-1) but also exhibited a higher Cd allocation to leaves (4%) and a strong decrease in leaf and stem dry mass after 90 days of exposure (~75% and 50% respectively, compared to control treatments). Taking together all the favorable features exhibited by T. superba as compared to other CAFS tree species and recognized phytoextractor tree species in the literature, such as Cd hyperaccumulation, high tolerance index, low Cd concentration in leaves, and high Cd allocation to the stem (harvestable as wood), this species is considered to have a high potential for cadmium phytoextraction in cocoa agroforestry systems.

Effect of Two Different Ageing Exposures on the Colour Stability of Transparent Polyurethane Finishing.

This paper deals with the influence of dark and light exposure on the colour change of a transparent two-component polyurethane surface finish. The surface finish with polyacrylic and aldehyde resin was applied to the surfaces of untreated and hydrothermally treated European beech, alder, Norway maple, and Paper birch wood. The test specimens were deposited indoors for 60 days. The colour values (lightness L*, redness + a*, yellowness + b*, chroma C*, hue angle h°) were expressed in the CIELAB system. The results showed that the colour difference of the finish surfaces of all hydrothermally treated wood species was 27-50% lower after the dark than when exposed to light. In the case of finished untreated wood, the colour difference was 51-73% lower after the dark than light exposure. Only the finished untreated and hydrothermally treated Norway maple wood surfaces showed similar and significant changes after both dark and light exposure. The lower value of the colour difference of the finished hydrothermally treated wood was due to the fact that steaming wood with saturated water steam has a positive effect on the overall colour stability of the finish and partial resistance to the initiation of photolytic reactions caused by light.

Fit-free analysis of fluorescence lifetime imaging data using chemometrics approach for rapid and nondestructive wood species classification

Abstract Conventional fluorescence spectroscopy has been suggested as a valuable tool for classifying wood species rapidly and non-destructively. However, because it is challenging to conduct absolute emission intensity measurements, fluorescence analysis statistics are difficult to obtain. In this study, another dimension of fluorescence, that is, fluorescence lifetime, was further evaluated to address this issue. A time-resolved fluorescence spectroscopic measurement system was first designed, mainly using a streak camera, picosecond pulsed laser at 403 nm, and a spectroscope, to collect the fluorescence time-delay (FTD) profiles and steady-state fluorescence intensity (FI) spectra simultaneously from 15 wood species. For data analysis, principal component analysis was used to “compress” the mean-centered FTD and FI spectra. Then, support vector machine classification analysis was utilized to train the wood species classification model based on their principal component scores. To avoid overfitting, ten-fold cross-validation was used to train the calibration model using 70 % of the total samples, and the remaining 30 % hold-out validation was used to test its reproducibility. The cross-validation accuracies were 100 % (5 softwoods) and 96 % (10 hardwoods), with test-validation accuracies of 96 % and 89 %.

Cross laminated timber bonding quality for different brazilian species and pressing levels

The proper choice of raw materials and manufacturing parameters for Cross Laminated Timber is essential to promote the proper bonding of the lamellas, aiming at their application in construction. However, few Brazilian species are currently used in the production of Cross Laminated Timber. The aim of this work was to characterize the bonding quality of four Brazilian reforestation species (Pinus elliottii, Eucalyptus grandis, Toona ciliata and Acrocarpus fraxinifolius) in the manufacture of Cross Laminated Timber with two-component polyurethane adhesive and five different pressure levels (from 0,1 MPa to 1,3 MPa). Bonding quality was evaluated through delamination and glue line shear tests based on the standard EN 14080 (2013). Delamination was affected by the wood species, and the best adhesion occurred for the Cross Laminated Timber manufactured with Pinus elliottii and Acrocarpus fraxinifolius at the bonding pressure of 0,7 MPa. Cross Laminated Timber bonding pressure did not affect the percentage of wood in the shear test fractured surface, whereas higher density Cross Laminated Timber showed higher percentages.