Search Results (45)

The Japanese cedar (Cryptomeria japonica), also known as sugi, is one of the most important trees in Japanese forests. It covers 44% of artificial forests, spanning approximately 4.5 million ha. It is cultivated in East Asia, the Azores archipelago, and some islands in the Indian Ocean. It is also grown worldwide as an ornamental tree in parks and gardens. The cultivation and use of sugi in Japan dates back centuries, and clonal forestry through cuttings has been practiced since the early 15th century. Its broad adaptability, genetic diversity, rapid growth, easy propagation, and precocious flowering—enabling early generational crosses—combined with their advanced genomic resources and efficient biotechnological tools, make sugi an outstanding conifer model. This review aims to provide an overview of the biotechnology and genetics of sugi for researchers and stakeholders. Full article

This paper explores the dynamic behavior of different wood species in the form of violin boards, based on experimental modal analysis using a single-input, multiple-output configuration. Thus, two groups of species were studied: the first group for the violin top plates, being analyzed Picea abies (spruce), Taiwania cryptomerioides Hayata (Taiwania), and Cryptomeria japonica (Japanese cedar), and the second group, with species for the back plates, such as Acer pseudoplatanus (maple), Populus nigra (poplar), Salix alba (willow), and Firmiana simplex (Chinese parasol). The results highlighted the frequency spectrum and the dominant resonance frequency, as well as the frequency damping, the signal processing analysis being based on Fast Fourier Transform and Wigner–Ville distribution of signals. The results highlighted that the lowest values of acoustic radiation are recorded for maple wood (7.8 m⁴ kg⁻¹ s⁻¹) and Taiwania (10.08 m⁴ kg⁻¹ s⁻¹), and the highest values for spruce (14.7 m⁴ kg⁻¹ s⁻¹) and Chinese parasol (15.58 m⁴ kg⁻¹ s⁻¹). Regarding the resonance frequency, the Taiwania and Japanese cedar plates present the dominant frequency around 600–635 Hz in comparison with Norway spruce having 920 Hz. The ratios between dominant frequencies of the Chinese parasol, poplar, maple, and willow are 1:1.42:2.62:2.98. It can be concluded that spruce and maple wood present the best dynamic properties, but when using other species, Japanese cedar wood for the top plate and Chinese parasol wood for the back plate represent species with potential in the construction of stringed musical instruments. Either a mechano-thermal treatment or an appropriate finish can enhance the acoustic qualities of these wood species, research that can be undertaken in the future. Full article

Sugi-pollinosis poses a significant socioeconomic and public health concern in Japanese society. Consequently, the use of male-sterile plants (pollen-free plants or PFPs) is anticipated in reforestation efforts. In this context, we developed an improved, simplified method for efficiently propagating sugi PFPs. In the present study, we compared the efficiency of different embryogenic cell lines (ECLs) in producing somatic embryos and examined how effectively these embryos germinate and convert into plantlets. We also evaluated the germination potential of somatic embryos stored for various durations at temperatures above freezing and room temperature. The production efficiency of somatic embryos ranged from 129.6 to 504.1 per plate, with an average of 349.8 across the ECLs tested. The overall average germination and conversion rates of somatic embryos were found to be 93.9% and 92.4%, respectively. Furthermore, although differences were observed among the evaluated genotypes, our five-year study demonstrated that sugi somatic embryos could be stored at 25 °C, 15 °C, or 5 °C for 6, 12, or 24 months, respectively, without a notable decline in germination capacity. The developed method enhances flexibility in plant production scheduling and facilitates the optimal timing for transferring somatic seedlings to the field. Full article

Fertilization is occasionally applied to promote early growth of outplanted tree seedlings. However, the effectiveness of fertilization can be obscured by topographic variations and competing vegetation. The aim of this study was to reevaluate the effects of fertilization and glutathione disulfide (GSSG) on Cryptomeria japonica D. Don (Japanese cedar) seedling height using a four-year dataset from a previous study showing no significant effects using linear models. The impact of treatment was examined using random forest, generalized additive models (GAMs), and structural equation models (SEMs), while accounting for topography and competing vegetation. Topographic features, including the topographic wetness index, were the primary determinants of height growth, reflecting C. japonica’s preference for moist environments. Although the effects of fertilization and GSSG were limited, the GAMs indicated marginal positive interactions in specific stable topographic contexts. The SEMs revealed that fertilization and GSSG indirectly negatively reduced height by increasing competing vegetation coverage. By applying these advanced statistical approaches, we demonstrate how treatment effects that conventional analyses might overlook can be detected, illustrating the methodological contribution of this study. These findings show that topography plays a dominant role in early C. japonica growth, and fertilization and GSSG provide only modest, context-dependent benefits. Full article

We investigated whether a cold front passed on the day when the most cedar pollen was dispersed in each year. When we looked at the 10-year period from 2015 to 2024, and found seven cases in which a cold front passed through the pollen survey area in the Tohoku region. In these cases, extremely large amounts of pollen were dispersed in the hours before and after the front passed. What they had in common was that the amount of pollen dispersion increased significantly at the time the front passed and before and after it. There were 3 cases when a large amount of Japanese cedar pollen was dispersed, even though a cold front did not pass through our Tohoku region. In these cases, large amounts of pollen were dispersed during the time when the warm front was located several hundred to one thousand kilometers south from Tohoku region. The large amount of dispersion continued as long as the fronts moved northward and got closer by several hundred kilometers to the Tohoku region, and the pollen dispersion decreased by the time the front reached the Tohoku region. Full article

The wood of Cryptomeria japonica (Japanese cedar or sugi) is widely used in building and adornment. This study aims to identify the composition of the volatile oils (VOs) extracted from C. japonica solid wood boards by gas chromatography–mass spectroscopy, and to investigate their antimicrobial, anti-inflammatory, and potential neuroprotective activities. A total of 58 volatile organic compounds (VOCs) were identified in the VOs from C. japonica solid wood boards with tree ages of 40, 50, and 60 years (VO-40, 50, and 60), with sandaracopimarinol (13.74–17.59%), ferruginol (10.23–11.29%), abieta-7,13-diene (8.20–13.66%), (+)-δ-cadinene (7.15–9.27%), cis-cubenol (4.36–6.36%), and sandaracopimarinal (3.23–6.04%) as major compounds. The VOs exhibited antifungal potential, especially VO-50 against Aspergillus fumigatus (MIC = 0.312 mg/mL), and VO-60 against Gloeophyllum trabeum (MIC = 1.25 mg/mL). However, VOs exhibited weak antibacterial activity (MIC > 10 mg/mL). Additionally, VOs (10 μg/mL) exhibited anti-inflammatory and potential neuroprotective activities, with VO-60 demonstrating the strongest inhibition of NO (25.79% reduction), TNF-α (52.24% reduction), and IL-6 (27.10% reduction) production in lipopolysaccharide-induced RAW264.7 cells, while increasing cell viability by 70.36% and reducing lactate dehydrogenase release by 41.10% in corticosterone-induced PC12 cells. Correlation and docking analyses revealed that sandaracopimarinal, sandaracopimarinol, β-eudesmol, and ferruginol were the potential active compounds. The results demonstrated that the volatile components from C. japonica solid wood boards not only enhance the board’s decay resistance, but also exhibit therapeutic potential for inflammatory disorders and neuropathic diseases. Full article

With growing worldwide interest in constructing larger and taller wooden buildings, wood properties, such as the dynamic modulus of elasticity (${MOE}_{dyn}$), have become increasingly important. However, the ${MOE}_{dyn}$ of trees and logs has rarely been considered in forest management because a method for estimating the ${MOE}_{dyn}$ of logs based on standing tree characteristics has been lacking. Herein, we explored the multiple relationships between the ${MOE}_{dyn}$ of logs and standing tree characteristics of Japanese cedar (Cryptomeria japonica) such as tree height, diameter at breast height (DBH), and tree age, including the stress-wave velocity of the tree, which is known to be correlated with the ${MOE}_{dyn}$ of logs. The relationship between the ${MOE}_{dyn}$ of logs and standing tree characteristics was investigated by considering the bucking position. Different trends between the bottom logs and upper logs were found for all characteristics, showing a multiple trend of tree characteristics with the ${MOE}_{dyn}$ of logs based on the bucking position. The top three generalised linear mixed models for the prediction of the ${MOE}_{dyn}$ of logs showed relatively high accuracies when the bucking position was considered as a random effect. Although the contribution of the stress-wave velocity of the tree was relatively high, adding tree age improved the accuracy of the model, and this model was selected as the top model. The model for the bottom log, utilising the stress-wave velocity and age of the tree as explanatory variables, was highly explanatory (R² = 0.70); however, the best model for upper logs was only moderately explanatory (R² = 0.44). In addition, tree height and DBH were selected as explanatory variables along with tree age in the second and third models, which suggested the importance of growth rate rather than tree size. Therefore, adding correlates associated to characteristics related to height growth, such as site index, and DBH growth, such as stand density, is expected to improve model accuracy. Full article

Wood drying is often accompanied by changes in mechanical properties due to external thermal energy. This study examined the influences of drying temperature on the mechanical properties of Japanese cedar based on the partial compression properties and bending properties. Two types of longitudinal specimens with quarter grain on both lateral surfaces were prepared under green conditions, followed by subsequent drying under each drying temperature (20 °C, 40 °C, 60 °C, 80 °C, and 100 °C). Then, the partial compression and bending tests were performed using the respective specimens. Young’s modulus perpendicular to grain, yield stress, and compressive strength obtained by the partial compressive test were highest for wood dried at 20 °C. It was considered that the decrease in mechanical properties was attributed to the thermal influences during drying at 100 °C and other factors such as compressive residual stress and cell walls collapsing at lower temperatures. The strain energy suggested that the effects of drying temperature became apparent, especially in the plastic region during loading in the direction perpendicular to the wood fiber. Bending properties showed little influence on drying temperatures compared to the partial compressive properties, whereas the fractures found under the loading point of the wood dried at 100 °C suggested a reduction in resistance to shear forces. Full article

About 40% of cedar pollinosis patients living in the Yamagata Prefecture showed pollinosis symptoms before the first day of the pollen season, which was determined by Durham samplers, the standard sampler for pollen information in Japan. The amount of Cry j 1 (major cedar pollen allergen) per cedar pollen is reported to be six pg. This amount is difficult to measure using the ELISA method, so we applied the highly sensitive ESR radical immunoassay method to measure the allergen; now we can provide information for sensitive patients. It revealed that Cry j 1 exists in orbicles and tapetum. It is presumed that it is smaller than pollen, so it comes from a place where cedar are already in bloom. It is desirable to obtain real-time information on an hourly basis. Currently, information from automatic cedar pollen monitors is becoming main-stream. However, this monitor may count during snowfalls, Asian dust flying, etc., even when there was no apparent pollen examined with a microscope. This paper describes the current status of automatic cedar pollen monitors, their usefulness, and their advantages and disadvantages in comparison with results obtained by other methods of measurement. Lastly, the paper describes expectations for cedar pollen information in the future. Full article

Breeding long-lived trees is challenging, but it has been shown that genomic information can be used to improve efficiency. In this study, genomic prediction (GP) was tested on selected individuals of a two-generation breeding population of Cryptomeria japonica, the most common plantation tree in Japan. In the 1980s, the second-generation plus trees (101 clones) were selected from about 8500 individuals obtained by cross-mating the first-generation plus trees (47 clones). RAD-seq based on 8664 SNPs was used to perform GP for three important traits in this population: tree height, wood stiffness, and male flower quantity. The association between traits and genotypes was modeled using five Bayesian models whose predictive accuracy was evaluated by cross-validation, revealing that the best model differed for each trait (BRR for tree height, BayesA for wood stiffness, and BayesB for male flower quantity). GP was 1.2–16.0 times more accurate than traditional pedigree-based methods, attributed to its ability to model Mendelian sampling. However, an analysis of the effects of intergenerational kinship showed that parent–offspring relationships reduce the predictive accuracy of GP for traits strongly affected by selection pressure. Overall, these results show that GP could significantly expedite tree breeding when supported by a deep understanding of the targeted population’s genetic background. Full article

In this study, short-term accelerated creep tests were conducted using the stepped isostress method (SSM) to investigate the impact of hydrothermal treatment on the long-term creep behaviour of Japanese cedar wood and to determine optimal hydrothermal treatment conditions. The results showed that SSM can effectively predict the creep behaviour of hydrothermally treated wood. Among the treatment conditions tested, Japanese cedar wood treated hydrothermally at 180 °C for 4 h exhibited higher flexural strength retention (91%) and moisture excluding efficiency (MEE) (44%) and demonstrated superior creep resistance compared to untreated wood. When subjected to a 30% average breaking load (ABL) over 20 years, the specimen’s creep compliance, instantaneous creep compliance, b value, activation volume, and improvement in creep resistance (ICR) were 0.17 GPa⁻¹, 0.139 GPa⁻¹, 0.15, 1.619 nm³, and 4%, respectively. The results indicate that subjecting Japanese cedar wood to hydrothermal treatment at 180 °C for 4 h has a negligible effect on its flexural properties but results in significant improvements in both dimensional stability and creep resistance. Full article

In this study, specimens were prepared from Japanese cedar (Cryptomeria japonica) with different thicknesses to determine the best hot-pressing conditions for wood compression layered structural materials (WCLS) through densification at various temperatures and compressing time conditions. However, residual stress-releasing after densification recovery can cause dimensional instability. To address this issue, the drying set method was combined with the compression-set recovery test to determine the best setting time. As a result, the bending strength and modulus of rupture (MOR) of WCLS increased by 9.98 ± 9.71 to 20.87 ± 13.09% and the modulus of elasticity (MOE) increased by 9.87 ± 11.92 to 22.40 ± 17.97%. The volumetric swelling coefficient (S), water absorption percent (WAP), and equivalent moisture content (EMC) decreased as the drying time increased. The anti-swelling efficiency (ASE) and moisture excluding efficiency (MEE) were found to be the highest at a drying time of 12 h, with values ranging from 13.20 ± 15.11 to 36.46 ± 6.83% and 15.18 ± 1.11 to 19.58 ± 8.31%, respectively. The drying method was found to be effective in increasing dimensional stability. The glass transition temperature (Tg) moved to a lower temperature as the compression-set increased, which was due to plasticization of wood caused by high temperature and pressure. The cell walls of WCLS presented viscous buckling, which provided effective dimensional stability. The thermal conductivity of Japanese cedar and each compression-set WCLS were 0.1863 ± 0.0071, 0.1520 ± 0.0147, 0.1817 ± 0.0106, and 0.1423 ± 0.0137 W/mK, respectively. The thermal conductivity of each WCLS increased with an increase in compression-set, but decreased by 10.67 to 22.52% compared to Japanese cedar. The total electricity energy consumption of each WCLS after 24 h of testing decreased with a trend of 30.50 ± 0.84, 29.83 ± 0.42, 29.57 ± 0.51, and 29.4 ± 0.36 kWH. Full article

Japanese cedar (JC, Cryptomeria japonica) pollen allergens are the primary cause of JC pollinosis, a widespread seasonal allergic disorder and a significant public health issue in Japan. Nevertheless, rare information on repressing the pollen allergens released from JC pollen is available. This study aims to validate the repression of allergen Cry j 1 (the dominant JC pollen allergen that triggers JC pollinosis) using todomatsu oil produced from Abies sachalinensis waste, through surface plasmon resonance (SPR) experiments, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and blind docking simulation. The findings revealed that todomatsu oil reduces the antibody reactivity and content of allergen Cry j 1 by 85.96% and 42.12%, respectively. The docking modeling suggested that alkyl hydrophobic forces, pi–sigma bonding, and hydrogen bonding are the principal motivating forces for todomatsu oil components to dock with allergen Cry j 1. More than 50% of the amino-acid residues docked by each todomatsu oil component (except α-pinene) are hydrophobic. Furthermore, oil components, especially β-maaliene, exhibited potent repression of allergen Cry j 1. Consequently, todomatsu oil, due to its inexpensive, available, convenient, and ecologically beneficial nature, is a viable measure to repress allergen Cry j 1. Full article

The unbridled expansion of moso bamboo (Phyllostachys edulis) occurs throughout the world and has a series of consequences. However, the effect of bamboo expansion on arbuscular mycorrhizal fungi (AMF) is still poorly understood. We assessed the changes in the AMF community during bamboo expansion into Japanese cedar (Cryptomeria japonica) forests by analyzing AMF in three forest types—Japanese cedar (JC), bamboo-cedar mixed (BC) and moso bamboo (MB)—using 454 pyrosequencing technology. We found that the AMF community composition differed significantly among forest types. The relative abundance of Glomerales decreased from 74.0% in JC to 61.8% in BC and 42.5% in MB, whereas the relative abundance of Rhizophagus increased from 24.9% in JC to 35.9% in BC and 56.7% in MB. Further analysis showed that soil characteristics explained only 19.2% of the AMF community variation among forest types. Hence, vegetation is presumably the main driver of the alteration of the AMF community. The α diversity of AMF was similar between JC and MB, although it was higher in BC. Overall, this research sheds more light on AMF community dynamics during moso bamboo expansion. Our results highlight that the consequences of bamboo expansion in monoculture forests differ from those in mixed forests. Full article

Sugi (Cryptomeria japonica D. Don) is an important forestry species in Japan. C. japonica ‘Spiralis’ is a mutant with twisted needles. The mutant is called Yore-sugi in Japan and is known as ‘Rasen’ in other countries. The twisted trait is regulated by a dominant gene called TWISTED NEEDLES, and it can be identified by observing the needles within 1 to 2 months after germination. The TWISTED NEEDLES gene may be useful for improving the efficiency of genome editing technology in C. japonica. In this study, we attempted to identify the linkage group of the TWISTED NEEDLES locus and investigate markers that sandwich this locus using the mapping family. First, we identified the linkage group containing the TWISTED NEEDLES locus based on the distortion from the expected segregation ratio using 32 mutant individuals of the mapping family. The segregation distortion showed that the TWISTED NEEDLES locus was located on the 11th linkage group (LG11). Next, a linkage map of LG11 was constructed based on genotype data from the single-nucleotide polymorphism (SNP) markers and double digested restriction site-associated DNA sequencing (ddRAD-seq) using 123 individuals of the MMY-1 family. On this map, six markers were located at the same position as the TWISTED NEEDLES locus. To investigate markers sandwiching the TWISTED NEEDLES locus, a partial linkage map around the TWISTED NEEDLES locus was constructed using 643 individuals of the MMY-1 family. The TWISTED NEEDLES locus was located in the 0.6 cM region between gSNP01822 and the other five markers (Contig_4705-179, Contig_4518-93, Contig_4398-118, gSNP04056, and Contig_4970-113). Full article