Wood Samples Research Articles

Wood anatomy and dendrochronological potentiality of some woody shrubs from the southern Mediterranean coast in Egypt.

In tropical and subtropical regions, much research is still required to explore the dendrochronological potential of their trees. This study aims to evaluate the anatomical structure and dendrochronological potential of three Mediterranean desert shrubs in Egypt (Lycium schweinfurthii var. schweinfurthii, L. europaeum, and Calligonum polygonoides subsp. comosum) supported by X-ray density. The results showed that the target species had distinct growth rings at macroscopic and microscopic levels. The vessel traits reflected the adaptability of each species with the prevailing arid climate conditions. After the exclusion of the non-correlated series, we obtained three site chronologies that cover the years 2013-2022 for L. schweinfurthii, 2012-2022 for L. europaeum, and 2011-2022 for C. comosum. The mean series intercorrelation was 0.746, 0.564, and 0.683 for L. schweinfurthii, L. europaeum, and C. comosum, respectively. The EPS (expressed population signal) values ranged from 0.72 to 0.80, while the SNR (species-to-noise ratio) ranged from 9.1 to 21.5. Compiling all series of L. schweinfurthii raised the EPS value to 0.86. The chronologies developed for the studied species were relatively short since we dealt with multi-stemmed shrubs. The average percentage difference between latewood density (LWD) and earlywood density (EWD) in C. comosum, L. europaeum, and L. schweinfurthii were 11.8% ± 5.5, 5.2%± 1.87, and 3.6% ± 1.86, respectively. X-ray densitometry helped in the precise determination of the ring borders of the studied species. The relationships between the radial growth of the studied species and the climate variables were weak to moderate but mostly not significant (i.e., r < 0.7). Generally, the radial growth of the target species had a weak to moderate positive correlation with temperature and precipitation during the wet season (winter), while negatively correlated with temperature for the rest of the year, particularly in summer. Our data agrees with earlier findings that ring formation starts at the beginning of the long vegetative stage, then the rest of the assimilated carbohydrates are directed to the flowering and fruiting at the end of the vegetative stages. For more efficient dendrochronological studies on subtropical and Mediterranean trees, we recommend carrying out xylogenesis studies, collection of phenological data, sampling 45-80 trees per species, using new techniques, and choosing homogeneous and close sites for wood sampling.

Long-term fungal inoculation of Ficus sycomorus and Tectona grandis woods with Aspergillus flavus and Penicillium chrysogenum

In the current study, two molds, Aspergillus flavus (ACC# LC325160) and Penicillium chrysogenum (ACC# LC325162) were inoculated into two types of wood to be examined using scanning electron microscopy-energy dispersive X-ray (SEM–EDX) and computerized tomography (CT) scanning. Ficus sycomorus, a non-durable wood, and Tectona grandis, a durable wood, were the two wood blocks chosen, and they were inoculated with the two molds and incubated for 36 months at an ambient temperature of 27 ± 2 °C and 70 ± 5% relative humidity (RH). The surface and a 5-mm depth of inoculated wood blocks were histologically evaluated using SEM and CT images. The results showed that A. flavus and P. chrysogenum grew enormously on and inside of F. sycomorus wood blocks, but T. grandis wood displayed resistance to mold growth. The atomic percentages of C declined from 61.69% (control) to 59.33% in F. sycomorus wood samples inoculated with A. flavus while O increased from 37.81 to 39.59%. P. chrysogenum caused the C and O atomic percentages in F. sycomorus wood to drop to 58.43%, and 26.34%, respectively. C with atomic percentages in Teak wood’s C content fell from 70.85 to 54.16%, and 40.89%, after being inoculated with A. flavus and P. chrysogenum. The O atomic percentage rose from 28.78 to 45.19% and 52.43%, when inoculated with A. flavus and P. chrysogenum, respectively. Depending on how durable each wood was, The examined fungi were able to attack the two distinct types of wood in various deterioration patterns. T. grandis wood overtaken by the two molds under study appears to be a useful material for a variety of uses.

RELATIONSHIP BETWEEN WOOD ANATOMICAL FEATURES AND SURFACE ROUGHNESS CHARACTERISTICS

This study aimed to investigate the relationship between surface roughness and anatomical features of wood in 15 different species of boards. Surface roughness was measured parallel and perpendicular to the wood grain using a surface profilometer, and anatomical features such as pore size and distribution were analyzed using microscopic techniques. The results showed that surface roughness perpendicular to the grain direction was consistently higher than that parallel to the grain direction for all wood samples. This difference in roughness was correlated with pore size and density. It shows that the larger pores and lower density lead to higher roughness perpendicular to the grain. The study also found that traditional hand planning methods (push and pull) produced a smooth surface finish, with no statistical differences in roughness.

EFFECTS OF PRESSING TEMPERATURE AND COMPRESSION RATIO ON DENSITY DISTRIBUTION AND HARDNESS OF SURFACE DENSIFIED POPLAR WOOD

Process parameters play an important role in wood surface densification. In this study, the poplar (Populus tomentosa Carr.) wood was heated on one side at 100℃, 150℃ and 180℃, and compressed in the radial direction with the speed of 10 mm/min. The initial thickness of the wood samples were 30 mm, 26 mm and 23 mm, and they were all compressed to 20 mm and resulting in three different compression ratios: 33.3%, 23.1% and 13.0%. When the surface densification completed, the density distribution and hardness of the densified and un-treated samples were measured and analyzed. Results show that the compressing temperature mainly decided the formation of the density distribution curve and the peak density increased with the increasing temperature; as the compression ratio increased, the peak density increased and the thickness of the densified zone broadened; the surface hardness was highly correlated with the density distribution which was affected by temperature and compression ratio, and as the peak density increased and the thickness of the densified broadened the hardness increased accordingly. Therefore, by optimizing the process parameters such as the compressing temperature and compression ratio could generate a targeted density distribution which has the desired hardness.

Bond-line strength, chemical properties and cellulose crystallinity of welded pine and itauba wood

ABSTRACT The aim of this research was to evaluate the bond-line strength and chemical changes of pine (Pinus taeda) and itauba (Mezilaurus itauba) joints welded by rotary friction and the use of the internal standard method with Rietveld refinement for the determination of the absolute cellulose crystallinity of wood samples. The specimens were composed of itauba dowels welded in substrates made of pine and itauba wood. The shear engaged by tensile pullout of the dowels was determined by mechanical tensile tests. Furthermore, macrostructural evaluation of the specimens and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD) tests were performed. The cellulose crystallinity was determined quantitatively by the internal standard method with Rietveld refinement and compared with the Segal and the deconvolution qualitative methods. The results reveal that itauba dowels welded in itauba substrates produce stronger joints (0.81 MPa) and slighter chemical changes than in pine substrates (0.62 MPa). The welded bond-line of itauba dowel and pine substrate has greater cellulose crystallinity than that of itauba dowel and substrate. The cellulose crystallinity is qualitatively consistent for the three applied methods, however, quantitatively, there are divergences between them.

Multi-Temporal Image Analysis for Preventive Conservation of Historical Musical Instruments

Artworks need to be constantly monitored to check their state of conservation and to quickly spot the eventual presence of alterations or damages. Preventive conservation is the set of practices employed to reach this goal. Unfortunately, this results generally in a cumbersome process involving multiple analytical techniques. Consequently, methods able to provide a quick preliminary examination of the artworks (e.g., optical monitoring) seem very promising to streamline preventive conservation procedures. We are especially interested in the study of historical wood musical instruments, a kind of artwork particularly subject to mechanical wear since they are both held in museums and also occasionally played in concerts. Our primary goal is to detect possible altered regions on the surface of the instruments early and thus provide the experts some precise indications on where to apply more in-depth examinations to check for potential damages. In this work, we propose an optical monitoring method based on the a-contrario probabilistic framework. Tests were conducted on the “Violins UVIFL imagery” dataset, a collection of UV-induced fluorescence image sequences of artificially altered wood samples and violins. Obtained results showed the robustness of the proposed method and its capability to properly detect altered regions while rejecting noise.

Modified Lignin Nanoparticles as Potential Conservation Materials for Waterlogged Archaeological Wood

Lignin is the most abundant component in archaeological waterlogged wood, making it a potential consolidant with high compatibility for historical wood conservation. However, its consolidation effect is limited by its low penetration into the wood. In this study, modified lignin nanoparticles (LNPs) were proposed for the first time as conservation materials for waterlogged archaeological wood. Two modified LNPs were prepared with low molecular weight, small size, and high solubility in ethylene glycol (EG) for consolidating waterlogged wood samples. These nanoparticles, hydrophilic aminated LNPs (ALNPs) and hydrophobic esterified LNPs (MALNPs), greatly improved the consolidation effect of waterlogged wood samples compared to LNPs. This was demonstrated by measuring their physical properties, dimensional stability, and mechanical properties. The surface color change was almost within the acceptable range for the human eye. We also discussed two different reinforcement mechanisms of ALNPs and MALNPs. ALNPs can form hydrogen bonds with hemicellulose/cellulose in the wood to strengthen the fragile wood cell wall, while MALNPs can fill the wood cell lumen to support the cell wall and prevent deformation during drying. Our work provides an approach of using biomaterials as consolidants for archaeological waterlogged wood and expands the use of lignin in this field.

STRUKTUR ANATOMI KAYU YANG DIPERDAGANGKAN DI KABUPATEN ACEH BESAR

This study aims to determine the anatomical structure of wood and its possiblity uses for trade in Aceh Besar District. The research was carried out by observing 13 wood samples from the Bogorience 1915 xylarium wood collection. The observed samples included macroscopic and microscopic characteristics. Macroscopic characteristics include texture, color, pattern, texture, and grain direction of the wood. Microscopic characteristics observed were growth circumference boundaries, vessels, pores, dots, and radii based on the International Association of Wood Anatomists (IAWA) book. Each preparation was observed using a microscope and analyzed descriptively. The results showed that the anatomical structures of the macroscopic and microscopic properties of the 13 Aceh Besar wood species varied in terms of texture, grain direction, radius size, crystal type, fiber length, vessel length, and fiber wall thickness. While the pattern, color, distribution of pores, type of dots, type of perforation area, type of parenchyma cells, and the composition of the cells composing the radius show uniformity, and two kinds of wood have prismatic crystals, namely Surian wood in upright cells and Bangkirai wood in straight cells lie down. The 13 types of wood, 46% include strong class I-II for construction, bridges, pillars, and floors. Meanwhile, 54% is classified as strong class III-V as a material for making furniture, doors, windows, and products that do not require heavy strength.

Moisture Content of Fresh Scots Pine Wood in Areas near Damage Caused by Harvester Head Feed Rollers

By damaging bark, mechanized harvesting deprives wood of its natural mechanical barrier. This study concerns the effect of this damage on the changes in moisture content that occur near the damaged areas of Scots pine (Pinus sylvestris L.). This study was carried out using 45 randomly selected 11 m long logged pine stems. Additionally, the effect of bark thickness on the depth of damage was measured. To determine the influence of the location of the damage and bark thickness on the wood moisture near the damaged region, wood samples were collected from two sections. The first was located one meter above the log’s base, while the second was located one meter from the end of the log. Two increment cores were taken by a Pressler borer in each section: one from the damaged wood zone and the second from the undamaged wood zone. The average bark thickness one meter from the base of the log was 11.2 mm, which decreased to 1.8 mm in the samples taken one meter from the top of the log. The average depths of the damage caused by feed roller spikes in the two sections were 3.9 and 3.8 mm, respectively, indicating that there was no significant effect of bark thickness on the depth of the damage. The wood samples collected near the damaged wood zone (DW) had about 13 percent lower moisture content than those taken from the undamaged zone (UDW). This difference was statistically significant. We observed greater mean moisture content closer to the top of the log for both the samples taken near the damaged zone and the samples taken from the undamaged zone. One meter from the base of the log, the moisture content difference between the DW and UDW was 9.8 percentage points, which was statistically insignificant. By contrast, significantly lower moisture content (−16%) was observed in the DW one meter from the top of the log.

Geographical origin classification of Phoebe zhennan and Phoebe bournei by solid phase micro-extraction and gas chromatography-mass spectrometry

Phoebe zhennan and Phoebe bournei are favored for their fine-grain, insect resistance, special fragrance, not easily cracked and deformed, which had been widely used in furniture and construction. Wood authenticity regarding different varieties and geographical origins is increasingly becoming a concern for consumers. Due to the difference in wood quality characteristics and economic value of genus Phoebe species from different geographical origins, it is important to establish a fast, efficient, and reliable method to discriminate the geographical origin of Phoebe zhennan and Phoebe bournei. Solid phase micro-extraction (SPME) was used as sample preparation approach and gas chromatography-mass spectrometry (GC–MS) technique was employed to analyze the volatile compounds. As a result, a total of 40 volatiles were identified by SPME–GC–MS among Phoebe zhennan samples from four origins, while 34 substances identified among Phoebe bournei samples. The wood samples of Phoebe zhennan and Phoebe bournei from different major production areas in China were able be discriminated by GC–MS spectroscopy. This finding indicated that genus Phoebe species from different climate zones had different chemical composition, which verified that the SPME–GC–MS technique can be used to classify different species of wood with characteristic compounds.

Evaluation of the efficacy of micro-Magnetic Resonance Imaging compared with light microscopy to investigate the anatomy of modern and ancient waterlogged wood

Light microscopy is the conventional method used to investigate wood anatomy, identify the wood taxon, and assess its conservation state. It generally requires the mechanical cut of thin sections from a sample to obtain informative images. When dealing with wooden artworks or ancient remains (e.g., archaeological waterlogged wood), it is important to avoid sample destruction. In this work the efficacy of micro-magnetic resonance imaging (μ-MRI) to investigate the anatomy of waterlogged wood is assessed in comparison with light microscopy. Images along the three anatomical directions (transverse, tangential and radial) of six modern wood species and one archaeological specimen of waterlogged wood (from the Neolithic site “La Marmotta”) were obtained both by μ-MRI and light microscopy. μ-MRI images were acquired virtually selecting 2D slices along the three wood anatomical directions. A 3D reconstruction was derived from 2D μ-MRI images. Conventional light microscopy histology was obtained by manually cutting thin sections. To the best of our knowledge, this is the first study in which high-resolution MR images and light microscopy images of the three anatomical directions of seven wood species are compared. The non-destructive μ-MRI approach allows to investigate the 2D and 3D topological organization of the whole waterlogged wood sample up to a resolution of 8 μm. Although the optical microscope attains higher image resolutions and remains superior in the observation of wood diagnostic characters, multi-parametric μ-MRI provides physiological investigation complementary to light microscopy, giving information concerning both a single section and the whole volume of the sample. The presented study may represent a starting point for further improvements of μ-MRI techniques applied to the non-destructive investigation of waterlogged wood samples, especially those of interest for cultural heritage.

Identification of Eight Pterocarpus Species and Two Dalbergia Species Using Visible/Near-Infrared (Vis/NIR) Hyperspectral Imaging (HSI)

Pterocarpus santalinus is considered among the finest luxury woods in the world and has potential commercial and medicinal value. Due to its rich hue and high price, Pterocarpus santalinus has often been substituted and mislabeled with other woods of lower economic value. To maintain the order of the timber market and the interests of consumers, it is necessary to establish a fast and reliable method for Pterocarpus species identification. In this study, wood samples of Pterocarpus santalinus and nine other wood samples commonly used for counterfeiting were analyzed by visible light/near-infrared (Vis/NIR) hyperspectral imaging (HSI). The spectral data were preprocessed with different algorithms. Principal component analysis (PCA) was applied in different spectral ranges: 400~2500 nm, 400~800 nm, and 800~2500 nm. Partial least squares discriminant analysis (PLS-DA) and square support vector machine (SVM) modeling methods were performed for effective discrimination. The best classification model was SVM combined with a normalization preprocessing method in whole spectral range (400~2500 nm), with prediction accuracy higher than 99.8%. The results suggest that the use of Vis/NIR-HSI in combination with chemometric approaches can be used as an effective tool for the discrimination of Pterocarpus santalinus.

Impact of thermal modification on swelling and mechanical behavior of Couratari spp.

Thermal modification mechanisms and their effects on physical and mechanical properties of native Amazon hardwoods are not yet completely understood. It is expected that such treatments can improve the properties of low-value Amazonian woods and sapwood residues. This study aimed to investigate the impact of heat treatment on the swelling and mechanical properties (strength and stiffness to Static Bending and Janka hardness) of tauari wood (Couratari spp.), a low-value Amazonian hardwood. For this, tauari wood samples were thermally modified in an electric oven under hot air irradiation at final temperatures of 160 °C, 170 °C, 180 °C, 190 °C, 200 °C, and 210 °C for 2.5 h. The main results showed that thermal modification increased the hydrophobicity of tauari wood without any noticeable effects on the mechanical behavior of the wood up to 200 °C. It was stated that up to 200 °C thermal modification is beneficial in terms of gains in hydrophobicity. In contrast, above 200 °C, despite an increase in hydrophobicity, consistent decreases in strength (MOR) and hardness were observed.

Surface protection of wood using cerium oxide nanoparticles dispersed paraffin wax nanoemulsion

Exposure to solar UV radiation and other environmental factors promotes the degradation and reduces the serviceability of the wood material under outdoor use. Oils and waxes have been found to be promising solutions for wood protection. This study elucidates the use of paraffin wax based emulsions incorporated with cerium oxide nanoparticles to improve weathering performance of wood. For this purpose, paraffin wax nanoemulsions were prepared by ultrasonication method using tween 80 as surfactant. Cerium oxide nanoparticles (conc. 0.5- to 2%) were added to provide protection against degradation caused by solar UV radiation. The storage stability of nano emulsion was assessed over a period of 30 days by measuring effective particle size and zeta potential. The microstructure of nanoemulsions was observed by optical microscopy and distribution of CeO2 nanoparticles on coated wood was observed through scanning electron microscopy (SEM). The chemical changes were analyzed by Fourier Transform Infrared spectroscopy (FTIR). Wood specimens of Pinus radiata coated with nanoemulsions were subjected to the accelerated weathering tests for 500h. The time dependent changes in surface color of uncoated and coated wood samples were examined. Moreover, the chemical changes on exposed wood surfaces were analyzed by ATR-FTIR spectroscopy. Stable and homogenous nanoemulsions with particle diameter between 200 and 400 nm were formed and exhibited excellent storage stability. Results of color changes showed that maximum degradation was observed in uncoated wood whereas wood coated with paraffin wax nanoemulsion alone could not improve the UV resistance. However, the addition of cerium oxide nanoparticles proved to be efficient in controlling the color changes on wood surfaces. The degradation of wood components reduced significantly in cerium oxide coated wood which was confirmed by FTIR results.

Proficient Lignocellulolytic Novel Bacterial Isolates from Diversified Galiyat Forests of Lower Himalaya

Lignocellulosic biomass needs attention as an alternative energy source to overcome the adverse impacts of fossil fuels. Diversified Galiyat forests of Lower Himalaya may represent the potential source of lignocellulose degrading microbiota, particularly the lytic bacteria. Therefore, soil and wood samples were collected from different sites of Nathiagali and Thandiani of Galiyat forests. The soil samples collected were clayey, with a pH between 6.7 and 7.0, and with an organic matter of 2.8%–2.9% in Nathiagali and 2.1%–2.2% in Thandiani. The soils were enriched with more diversified cultivable bacteria (9 Log CFU/g) than the respective wood samples (7.4–8.6 Log CFU/g). Out of 90 bacteria, 22 isolates were efficient for cellulose degradation, 14 for xylanase activity, and 10 for laccase production. Cluster analysis showed that lignocellulolytic bacteria were grouped based on the sample medium (soil–wood) rather than the sampling site (Thandiani–Nathiagali). Efficient bacteria were also sequenced, and we found that cellulase production was prevalent in Pseudomonas spp. while laccase activity was diverse among taxonomically varied bacteria. Moreover, Stenotrophomonas sp. TS2B1 performed the best for corncob xylose degradation. Overall, the results suggest that Galiyat forests represent diverse lignocellulolytic microbial populations which should be further evaluated for applications in lignocellulosic waste management and for potential consequent fuel production.

Fire protection of wooden building structures

The paper covers the issues of fire protection of cellulose-containing materials, in particular wood. It is shown that despite a number of valuable properties that wood possesses, it is a rather flammable material by its composition. It is known from the literature that one of the most important steps in protecting wood from fire is fire protection treatment. It is carried out in two main ways: surface treatment (applying special compounds to the wood surface to form a fireproof layer) and deep impregnation of wood with flame retardants. For the fire protection of OSB samples, a water-based intumescent paint consisting of a system of flame retardants in combination with fillers, pigment, and functional additives was developed. The research was conducted using analytical and experimental methods, which consist of analyzing and studying the provisions of national standards that describe the method for determining the flammability group of substances and materials and the method for determining the fire protection efficiency of fire retardants. The experimental part of the study involved the manufacture of test samples, application of fire retardants to them, recording the temperature of gaseous combustion products, the maximum temperature increase, the time interval for reaching the maximum temperature, the weight of the samples, and the weight loss of the samples. The research methodology states that the wood samples were tested in accordance with DSTU 8829 at the OTM installation. It also provides means for measuring the flue gas temperature, test time, and determining the mass loss of samples before and after testing. The test results showed that the developed fire retardant based on intumescent paint provides a group of refractory materials in accordance with DSTU 8829, i.e., the wood protected by this method belongs to refractory materials, namely: the flue gas temperature does not exceed 260˚C, the mass loss of samples after testing is not more than 60%.

Identification and analysis of ancient ship wood excavated at Nantong hydraulic site

The Nantong Ancient Ship refers to an ancient Chinese wooden ship of the late Ming Dynasty excavated in Nantong city in December 2022. This paper identifies the wood and discusses its related analysis. Wood samples extracted from the Nantong Ancient Ship were studied from the viewpoints of anatomy, physics, and chemistry. Microscopic identification results concluded that willow and Chinese fir were the main wood species used to make this ship. The content of holocellulose in the ancient wood was only 37.9 to 38.9%, while the content of lignin was 55.2 to 56.4%. The cellulose crystallinity of ancient wood was 39 to 42% lower than that of healthy recent wood. Fourier transform infrared (FTIR) spectra revealed that the deterioration of ancient wood caused cellulose and hemicellulose degradation, but no apparent lignin alteration. The results could provide a basis for drawing up a conservation plan for the Nantong Ancient Ship. They could also provide a reference for the research and conservation of other archaeological shipwrecks in China.

Production of Charcoal Through Partial Combustion in a Wood Stove

Philippines is a country rich in natural resources that can be converted into biomass fuels, such as charcoal. This study aims to determine the viability of producing charcoal through partial combustion using Mahogany and Ipil – Ipil wood in a wood stove before burying the charred wood samples in clay soil. Sample preparation was done by machining pruned branches into a size of 1-in diameter by 6-in length, then drying them until their moisture content was below 20%. The dry wood samples were then charred in a wood stove at different residence times. After reaching the residence time of a trial, the charred sample was wrapped in tin foil and buried in clay soil to cool for 24 hours. Afterwards, proximate analysis and bomb calorimetry were done on the charcoals produced. Results of the tests show that with longer residence time, charcoal yield decreased; moisture content increased due to increase in charcoal hygroscopicity; volatile matter decreased due to devolatilization; and fixed carbon content increased. Also, ash content increased for Mahogany charcoals while in Ipil-Ipil, it hardly varied. Furthermore, Ipil-Ipil charcoals were found to have greater calorific values than Mahogany charcoals due to Ipil – Ipil wood having greater calorific value.

Efficacy of Fungus Comb Extracts Isolated from Indo-Malayan Termite Mounds in Controlling Wood-Decaying Fungi

The authors have recently investigated the chemical components and bioactivity of fungus comb from Macrotermes gilvus Hagen mounds. The ethyl acetate, methanol, and water extracts of the fungus comb contained active compounds which are preventing the growth of Aspergillus foeti-dus, one of the most economically important wood-staining fungi in Indonesia. In this present study, the bioactivity of the fungus comb extracts was examined against the white-rot fungus Schizophyllum commune Fr. For the purpose of generating a realistic in-service type of environment, the extracts were evaluated according to modified EN-113 after impregnated into wood samples by the vacuum-pressure method, following in-vitro antimicrobial susceptibility test. The results showed that ethyl acetate extract at concentrations ranging from 2 to 6% and methanol extract at a concentration of 6% presented high bioactivity against S. commune. This result was established through optical microscopy images, which demonstrated the absence of fungal mycelia in the vessels of wood samples treated with EtOAc extract at concentrations of 2%, 4%, and 6%, as well as MeOH extract with a concentration of 6%. The toxic values of the ethyl acetate and methanol extracts were determined to be 6.17% and 7.72%, respectively. Based on UPLC-HRMS analysis, azelaic acid, and erucamide were discovered as the dominant components in ethyl acetate extracts, which are anticipated to be the most active compounds. It appears that ethyl acetate extract, as well as methanol extract, can be considered as novel preservative sources for controlling wood-decaying fungi.

Analysis of stress development during kiln drying of beech timber

Before use, timber must have reduced moisture content. Kiln drying causes cracking risk. This study aims to evaluate the risk of cracking during the drying of beech wood samples using the response surface methodology. Additionally, we aim to develop an empirical model that describes critical tensile stress during the early drying stages and the air parameters commonly used in kiln-drying schedules for beech timber, specifically, the effects of dry-bulb temperature (DBT) and wet-bulb depression (WBD). Nine options of drying conditions were analyzed in the study according to the Central Composite Design assumptions; they were combinations of three options of DBT (30, 40, and 50 °C) and three options of WBD (4, 5, and 6 °C). During the experiments, tangential shrinkage of the wood samples was completely restrained with a load cell that measured generated tensile drying stresses. The results of the ANOVA analysis confirmed that the DBT is the only factor significantly influencing the tensile stress at failure (σf). The second-order effect between DBT and WBD has also been confirmed. The drying condition causing the highest risk of cracking was shown using the multiple contour plots of tensile stresses and the moisture content at failure (MCf). Reliability theory was used to predict the cracking risk of wood tissue. The analysis confirmed the dependence of the cracking risk of wood tissue on drying conditions. When DBT is equal to 30 °C, the cracking risk increases as the air relative humidity (RH) decreases. However, during the drying of beech wood samples at a temperature of 50 °C, decreasing the RH in a range corresponding to the increase of WBD from 4 to 6 °C reduces the cracking risk, which is indicated by the lower moisture content at failure (MCf) of the wood samples.Graphical