Heartwood colour is often an important factor in determining timber prices. However, the determinants of intraspecific variation in heartwood colour, which is useful information for sustainable wood marketing, are little understood, especially at the local scale in cool temperate forests. Because heartwood is produced as a secondary compound and photosynthesis is regulated by nitrogen (N) in cool temperate

Traditional glulam beam connection mode has a weak ability to transfer bending moment, leading to insufficient joint stiffness and mostly in the form of simply supported beams. To make full use of material strength, a novel prestressed glulam continuous beam was proposed. On this basis, this paper put forward a new method to further improve the mechanical performance of the beams by controlling prestress

Shear experiments on mortise and tenon joints with top and bottom notches in the beam end were conducted with the length of the tenon as a variable. In addition, material experiments were performed to investigate the structural performance of the fracture modes of the joint. The experimental results show that when the lower notch at the beam end experiences splitting, the shear forces were identical

We previously reported the species-specific annual ring formation characteristics of three conifers (slash pine (Pinus elliottii), hinoki (Japanese cypress, Chamaecyparis obtusa) and sugi (Japanese cedar, Cryptomeria japonica)) grown in the same stand over 2 years. We found that the species-specific annual ring formation characteristics affected the inherent difference in wood density among these conifers

The condensation reaction of lignin is believed to interfere with delignification in alkaline pulping processes, without any clear evidence, which has motivated us to quantitatively revisit it. This paper is the first of a series, and hence we employed the simplest model system using 4-hydroxymethyl-2-methoxyphenol (vanillyl alcohol, Va) and 2-methoxy-4-methylphenol (creosol, Cr) under soda cooking

The conventional stake test is widely used to evaluate wood durability. The test monitors the deterioration level observed on stakes partially inserted into the ground. The test results are conventionally expressed as the relationship between the mean deterioration level and exposure periods. Durability is compared between the stake groups based on the test results; however, there is no scientific

The sapwood and heartwood of plantation sugi wood (Cryptomeria japonica), and plantation hinoki (Chamaecyparis obtusa) wood were flat-sawn into timbers, then kiln-dried to a MC level below 12%. These timbers were further processed into specific sizes and wetted on the surfaces, preheated at 150 °C and radially compressed into sandwich compressed timbers. Density distribution, compressed layer(s) position

Wood-based panels are made by consolidating mats of resinous wooden raw materials under a hot-pressing process. This study investigates the effect of face-layer moisture content (MC) and face–core–face (FCF) ratio of mats on the temperature and vapor pressure behavior during the hot-pressing process. Raising the face-layer MC and lowering the face-layer thickness was expected to reduce the time of

The pretensioning force in bolted joints enhances the lateral strength of the connections, and causes the embedment of metal washers into wood. Despite the significance of embedment behavior in the design of bolted joints, its mechanism has yet to be fully understood. In this study, the mechanism of the embedment of a metal washer into wood along the radial direction was examined through three-dimensional

The static lateral load–slip behavior of a single-shear plywood-to-plywood single-staple connection (SPSC) was investigated experimentally. A mechanics-based approach was used to develop mechanical models for deriving estimation equations for critical lateral loads of SPSCs based on failure modes of staple legs and connection member materials developed during static lateral loading process. Experimental

This paper describes results and analysis of experimental testing of entire and partial compression strength and stiffness parallel to the grain of solid timber (Japanese cedar). To investigate the spreading effects, the size effect of strength and stiffness, and the mechanism of the damage zone located close to the loading plates, tests on 90 specimens were performed. As a result, it was observed

Snow damage is problematic when cultivating bamboo shoots, and “Uradome”, the practice of removing the tips of new shoots, is used as a preventative measure. Producers perform “Uradome” at empirical times, but there is no scientific basis for this. We hypothesized that differences in the structure and composition of the cell wall might affect the optimal timing of "Uradome" and analyzed the cell wall

This study examined the influence of moisture content (MC) on NO2 sorption ability of cedar (Cryptomeria japonica) wood using the specimens with different MCs. Four MC conditions were applied, namely 0%, 8.6%, 12.7% and 16.5%, based on the differences of bonding condition of water molecule in the wood substances. As a result, the NO2 sorption volume increased drastically due to the presence of water

Bamboo has been widely used as a load-bearing material in construction; however, there are limited studies on the stability of slender original bamboo columns. Based on the experimental investigation of thirty-nine original bamboo columns, parametric analyses were conducted to investigate the influence of the diameter–thickness ratio, cross-sectional area and slenderness ratio on the axial compression

We conducted our research with the aim of determining whether the “egumi” taste of moso-bamboo shoots differs depending on the production area and how the “egumi” taste of bamboo shoots from Yamagata Prefecture, which is near the northern limit of cultivation, differs. The investigation was conducted using conventional chemical analysis methods to quantitatively evaluate the presence and content of

In this study, the lateral resistances of mass timber shear walls were investigated for seismic design. The lateral resistances were predicted by kinematic models with mechanical properties of connectors, and compared with experimental data. Four out of 7 shear wall specimens consisted of a single Ply-lam panel and withdrawal-type connectors. Three out of 7 shear wall specimens consisted of two panels

Three-point bending tests were performed on specimens of glued laminated timber with different specimen heights to failure to determine the relationship between specimen height and bending strength under tension perpendicular to the grain. For the three-point bending tests, two types of glued laminated timber composed of homogeneous grade timber, as specified in the Japanese Agricultural Standard,

The thermal degradation reactivities of hemicellulose and cellulose in wood cell walls are significantly different from the thermal degradation behavior of the respective isolated components. Furthermore, the degradation of Japanese cedar (Cryptomeria japonica, a softwood) is distinct from that of Japanese beech (Fagus crenata, a hardwood). Lignin and uronic acid are believed to play crucial roles

This article aims to investigate the contact characteristics of mortise and tenon (M&T) joints in the traditional timber structures. In particular, the normal embedded compressive contact between contact surfaces of M&T joint was investigated. Based on basic contact theory and contact characteristics between mortise and tenon, a normal elasto-plastic contact model, which can reflect the real normal

This study has quantified basic wood density and various types of wood shrinkage in relation to initial spacing (or initial planting density) and tree growth based on a 48-year-old black spruce (Picea mariana) spacing trial in eastern Canada. A total of 139 sample trees were collected from four initial spacings (3086, 2500, 2066, 1372 trees/ha) for this study. Analyses of variance (ANOVA) show that

Monomeric C6-C2-type lignin model compounds with a p-hydroxyphenyl (H), guaiacyl (G), syringyl (S), or p-ethylphenyl (E) nucleus (1-phenylethanol derivatives) were individually oxidized by MnO2 at a pH of 1.5 and room temperature. The results were compared with those of the corresponding C6-C1-type benzyl alcohol derivatives obtained in our recent report to examine the effect of the presence of the

The paper proposes the use of microwave irradiation to lower the initial moisture content of wood chips. The study involved willow and fir chips fractionated by means of a sieve separator and unfractionated ash chips. The wood chips were exposed to a constant microwave power of 800 W for 30 s, 60 s, 120 s and 180 s. The chips were weighed before and after irradiation to measure loss of moisture. It

This study investigates the physiological responses and subjective perceptions of touching wood. In particular, it focuses on their respective relationships with the amount of heat transfer across the hand–material interface during contact. The study participants included 55 university students (20 females and 35 males) who gave written informed consent. The participants’ blood pressure, pulse rate

Bamboo is now widely used in construction, papermaking, textile, furniture and other fields because of its renewable, fast-growing, high-strength, high-yield and easy processing. However, compared with wood, bamboo and bamboo products are more vulnerable to damage by fungi and pests. An effective and eco-friendly method is urgently needed to improve their physical and chemical properties, decay resistance

This study attempts to clarify thermodynamic quantification on interaction between poly(vinyl alcohol) (PVA) and wood-derived cellulose nanofibrils (CNFs) obtained by aqueous counter collision (ACC) method. Aqueous mixtures of PVA/ACC-CNFs with various fiber widths were cast as the target materials. The interfacial interactions between the two components were characterized through thermodynamic evaluation

Wood anatomical traits of xylem are the characteristics of tree rings at cellular and subcellular scales providing important insights on structural features and their linkage to the environment. Therefore, studying the relationship between anatomical traits and environmental changes not only provide physiological explanations, but also provide a new vision of studying the adaptation process and response

In this study, the out-of-plane shear strength of hybrid cross-laminated timber (CLT) with outer layers of hinoki (hinoki cypress, Chamaecyparis obtusa) and inner layers of sugi (Japanese cedar, Cryptomeria japonica) is investigated for four different layer configurations. To investigate the influence from rolling shear properties of cross layers on the shear strength of CLT, stress analysis was conducted

Subalpine conifers are highly sensitive to climatic changes. In these trees, the intra-annual dynamics of cambial activity and phenological process in xylem development are closely associated with climatic conditions. However, these scientific findings have not been verified for subalpine conifers in the Republic of Korea. Therefore, we initiated such a study with four subalpine conifers, viz. Abies

Chestnut bur is an agro-waste material generated in the chestnut production. It is a tannin-rich lignocellulosic material which might be a promising raw material for low-formaldehyde composite particleboard production when using urea–formaldehyde (UF) as bonding adhesive. In this study, the characteristics of chestnut bur were analyzed to assess its application value for composite panel. Five-type

The hot-disk method is a transient method for the measurement of thermal properties. This method can measure both the thermal conductivity and thermal diffusivity in a short time for isotropic materials. To establish a method for measuring the thermal properties of wood by the hot-disk method, the relationship between the thermal properties of wood obtained by the hot-disk method and those obtained

The thermal degradation reactivities of cellulose and hemicellulose are substantially different in Japanese cedar (Cryptomeria japonica, a softwood) and Japanese beech (Fagus crenata, a hardwood). Uronic acid and its salts act as acid and base catalysts, respectively, and their specific placement in the cell walls has been considered a factor that influences degradation reactivity. In this study, the

Although wood cross sections contain spatiotemporal information regarding tree growth, computer vision-based wood identification studies have traditionally favored disordered image representations that do not take such information into account. This paper describes image partitioning strategies that preserve the spatial information of wood cross-sectional images. Three partitioning strategies are designed

The transfer factor (TF) of radioactive cesium-137 (137Cs) to shiitake (Lentinula edodes) cultivated on bed logs varies greatly. Therefore, the present study investigated which factors affect the TF using stable cesium-133 (133Cs) and sawdust medium with 5% rice bran as a model, which had similar 133Cs TFs to bed-log cultivation. It was found that the Cs concentration and nutrient concentration (represented

Taiwania (Taiwania cryptomerioides Hayata) has long been regarded as a living fossil from the Tertiary period of Mesozoic Era for its distinguished yellowish-red color with purplish-pink streaks presented in its heartwood. With this elegant appearance that matches the color “red” for good fortune in the Taiwanese culture, Taiwania is supposed to be a popular wood in Taiwan where it is a native species

Increased wood density is obtained by compressing the wood porous structure under suitable moisture and temperature conditions to improve its physical, mechanical and color properties. A recently proposed wood densification method based on partial removal of lignin and hemicellulose in hot water solution of sodium hydroxide and sodium sulphite has shown promising results on solid wood. However, its

Inspired by the use of rift-sawn softwood board for covering curved surfaces in Kokerabuki, a traditional Japanese roofing method, we investigated the flexural anisotropy of wood caused by its end-grain orientation. We measured the flexural displacement of softwood species, Chamaecyparis obtusa and Cryptomeria japonica, and hardwood species, Populus suaveolens and Cerasus serrulata. For the softwood

Low permeability of wood causes problems during drying of timber. This study evaluated the effects of microwave (MW) pretreatment on the conventional drying behavior and mechanical damages of Chinese fir lumber. MW pretreatment of lumber was performed at applied MW energy of 43 kWh/m3, and then, the samples were dried in a laboratory drying kiln. The results showed that the drying rate was effectively

The microtensile properties of mechanically isolated compression wood (CW) and opposite wood (OW) tracheids of Chinese fir (Cunninghamia lanceolata) were investigated and discussed with respect to their structure. Major differences in the tensile modulus and ultimate tensile stress were found between CW and OW fibers. Compared to OW, CW showed a larger cellulose microfibril angle, less cellulose content

It is important for civil engineering applications to investigate resistance to wood decay in aqueous environments. DNA from microorganisms inhabiting logs (groynes) that had been used for about 15 years as a water control system to prevent riverbank erosion was extracted and the microbial community structure was examined. DNA was extracted from specimens in four sections, above and under the water

We investigated the effect of ultrasonic treatment on Malas (Homalium foetidum) gas permeability and sound absorption coefficient using the transfer function method. Results showed a longitudinal average Darcy permeability constant of 2.02 (standard deviation SD 0.72) for untreated wood and 6.15 (SD 3.07) for ultrasound-treated wood, a permeability increase of 3.04 times. We also determined the average

We performed an analysis using isoelectric focusing to comprehensively clarify the isozyme composition of laccase derived from Japanese lacquer tree, Toxicodendron vernicifluum. When water extracts of acetone powder obtained from lacquer were subjected to isoelectric focusing, five bands within pI 7.35–9.30 and nine bands within pI 3.50–5.25 were detected using Coomassie staining. Similarly, laccase

Various design codes and design proposals have been proposed for glued laminated timber beams with round holes, assuming that the entire beam is composed of homogeneous-grade timber. However, in Japan, glued laminated timber composed of homogeneous-grade timber is rarely used for beams. In this study, the difference in the load-bearing capacity of glued laminated beams composed of homogeneous-grade

This work concerns basic research on the concept of wood hardness in a sense similar to Brinell or in the modified sense of Monnin. The experimental part of this article is based on research carried out on beech wood with six indenters: three ball indenters of 10, 15 and 30 mm and three cylindrical indenters of 10, 15 and 30 mm. On the basis of measurements for a wide range of loads, relations analogous

This study examines a simple estimation method for the measurement of the mass of an on-site log through a vibration test. In this method, rather than the log itself, a cut end portion is weighed. For this purpose, the vibration method with additional mass (VAM) was applied to Sitka spruce (Picea sitchensis Carr.) circular truncated cones (model log) and Japanese cedar (Cryptomeria japonica D. Don)

Over the past few decades, the sustainable forest area in China has increased remarkably, with 2400 million cubic meters of eucalyptus produced in 2018 in Guangxi which is the largest plantation area in China. In this study, the effect of alternating lamination using soft poplar veneers and hard eucalyptus veneers, on the mechanical properties of laminated veneer lumber (LVL), was examined. Eucalyptus

Traditional Chinese timber buildings are lightweight, flexible, and quite vulnerable to wind. This paper aims to present a methodology for evaluating the wind-induced vibration performance of early Chinese hall-style timber buildings based on numerical simulations. First, the architectural and structural characteristics of early Chinese hall-style timber buildings were presented and analyzed. It is

The thermal reactivities of cellulose and hemicellulose are significantly different in cell walls when compared with isolated components and differ in Japanese cedar (softwood) and Japanese beech (hardwood). Uronic acid bound to xylan promotes the thermal degradation of cellulose and hemicellulose, and its effect is different depending on the form of free acid (acting as an acid catalyst) or metal

The column, which is the vertical main structural part of the building, bears the force transmitted from the upper beam and slab and is a crucial part of the structure. In this study, the columns with a rectangular section cut from poplar were reinforced by basalt fiber-reinforced polymer (BFRP) strips with four different reinforced configurations. The mechanical behaviors of the specimens were also

To understand the fuel characteristics of a waste shiitake mushroom bed derived from hardwood chips, the moisture content at the time of disposal and after 1 month, as well as its calorific value, ash content, and elemental composition, were investigated. The moisture content on a wet basis (MCw) was 78% at the time of disposal and was as high as 63% even 1 month after disposal. It is considered that

In this study, further research on an enzymatic hydrolysate-ammonium dihydrogen phosphate (EHADP) adhesive was carried out. Appropriate hot pressing conditions were clarified by measuring the bond strength of three-ply plywood bonded with EHADP adhesive, and the results indicated that the appropriate fabricate conditions were 170 °C and 5 min. The value of wet shear strength fulfilled the requirements

Termites are ecologically significant in positive and negative ways; their role in breaking down debris greatly benefits forest environments, but this activity renders them a pest in domestic environments. This study examines the effect of nutrition on the feeding preference of termite Coptotermes formosanus Shiraki. Among 11 nutrition options tested, dipotassium phosphate (DKP) most significantly

To study the force–displacement relations of bolted timber joints with slotted-in steel plates, we performed a monotonic loading test parallel to the grain on 24 specimens. The influences of the bolt diameter, timber thickness, and their ratio were considered. As shown by the test results, the joints had a high deformation capacity and experienced a linear stage, a stiffness degradation stage, a yield

Japanese cypress (Chamaecyparis obtusa) wood powder impregnated with Fe3+ ions was carbonized using one-step and two-step procedures, and the iron-loaded charcoal was examined using Mössbauer and Raman spectroscopy to elucidate the physicochemical states of iron and carbon after carbonization at various temperatures. In the one-step procedure, the Mössbauer spectra confirmed that charcoal carbonized

The aim of the study was to develop a simple and cost-effective method to improve thermal insulation and hydrophobicity of wood. Herein, we attempted to use commercially available silica aerogel powders suspended in ethanol to treat the wood by a simple vacuum impregnation process. The effects of particle size (20 µm and 40 nm) of silica aerogels and the number of impregnation cycles (1, 3, and 5 cycles)

A non-phenolic C6-C2-type lignin model compound with the β-O-4 bond, 2-(2-methoxyphenoxy)-1-(3,4-dimethoxyphenyl)ethanol (I), was acidolyzed in aqueous 82% 1,4-dioxane containing HBr, HCl, or H2SO4 with a concentration of 0.2 mol/L at 85 ℃ to examine the differences between these acidolyses. Compound I primarily converted to an enol ether compound, 1-(2-methoxyphenoxy)-2-(3,4-dimethoxyphenyl)ethene

The aim of this study was to predict the withdrawal resistance of a screw in hybrid cross-laminated timber (CLT) composed of two types of lamina layers. A theoretical model to predict the withdrawal resistance was developed from the shear mechanism between a screw and the layers in hybrid CLT. The parameters for the developed model were the withdrawal stiffness and strength that occurs when a screw

The purpose of this study is to analyze the pore structure for the heartwood, intermediate wood, and sapwood sections in three species of softwood (hinoki, Douglas fir, and hemlock) and to investigate the correlation of gas permeability depending on pore structure. For this study, gas permeability and pore size were measured by capillary flow porometry, and classification of a novel method was performed

Wood is usually stable under relatively dry conditions but may still undergo slow deterioration. The type of deterioration and how these processes affect the wood are important questions that need consideration if old wooden structures are to be studied and properly preserved. The aim of this paper is to establish the main structural and morphological differences between new and naturally aged European

Alzheimer's disease is the most common form of dementia, and neurological disorder from beta amyloid (Aβ) peptide is regarded as a cause of Alzheimer's disease. In this study, the authors evaluate Aβ toxicity reduction effects of major diterpenes isolated from sugi wood by bioassay using Caenorhabditis elegans and examined its relationship with the antioxidative activity. Among the six kinds of sugi

To utilize woody waste for the inhibition of harmful algae, we examined the growth inhibitory activities of sugi (Cryptomeria japonica) bark powder against Microcystis aeruginosa, which is a cyanobacteria species that causes algal blooms in lake or pond areas. The growth of M. aeruginosa was inhibited by the direct mixing of sugi bark powder into media in flasks. The inhibitory activity against M.