Search Results (115)

Driven by the growing demand for quality assurance within the essential oil (EO) industry, this study builds upon prior seasonal chemical and anticholinergic characterizations of Azorean Cryptomeria japonica foliage (Az–CJF) EO by presently evaluating the seasonal variations in its antibacterial, antioxidant, and anti-inflammatory activities. Autumn (Aut–EO) and spring (Spr–EO) samples exhibited a uniform, targeted antibacterial profile exclusively against Gram-positive bacteria, with a MIC of 5.0 mg/mL for Micrococcus luteus and ≥10.0 mg/mL for Bacillus licheniformis, B. subtilis, and Staphylococcus aureus. Antioxidant capacities also remained seasonally consistent within each of the three individual assays, namely the DPPH, ABTS, and β-carotene bleaching assays (EC₅₀ ≤ 10.5, ≤ 6.0, and ≤0.3 mg/mL, respectively), suggesting a stable potential for lipid peroxidation inhibition. In addition, both EOs protected against bovine serum albumin denaturation (84–98%) with no statistically significant differences, generally outperforming diclofenac sodium (70–87%). Notably, anti-inflammatory activity via COX pathways proved to be seasonally dependent: Spr–EO inhibited COX-1 and COX-2 more significantly than Aut–EO, with both EOs showing COX-1 selectivity (IC₅₀ of 284 vs. 560 µg/mL). Although less potent than diclofenac sodium (COX IC₅₀ < 0.2 µg/mL), the superior activity of Spr–EO was supported by molecular docking, suggesting this enhanced effect is driven by higher contents of kaur-16-ene and oxygenated sesquiterpenes (such as α- and β-eudesmol). These bioactivities provide baseline parameters for batch standardization. By merging stable core properties with seasonal anti-inflammatory profiles, Az–CJF EO shows promise as a natural multi-target-directed ligand (MTDL) for therapeutic applications within a circular bioeconomy. Full article

Wood-based composite panels are renewable and low-carbon materials, but their inherent flammability limits their broader use in applications requiring improved fire safety. In this study, expanded graphite (EG) was incorporated into a melamine–formaldehyde (MF) adhesive system to fabricate fire-retardant Japanese cedar (Cryptomeria japonica) plywood. Two EG types with different expansion ratios, 200-fold expanded graphite (200EG) and 450-fold expanded graphite (450EG), were added to the bonding layer at 10, 20, 30, and 40 phr. The effects of EG expansion ratio and content on the physicomechanical properties, combustion behavior, char morphology, and pyrolysis gas evolution of plywood were investigated. EG had limited effects on air-dried density and moisture content, but increasing EG content reduced bonding shear strength and parallel-direction flexural properties, particularly in the 450EG series. Cone calorimeter analysis showed that EG reduced the heat release rate and total heat release by promoting the formation of an expanded carbonaceous barrier layer. Among the tested formulations, 30 phr 200EG provided the most favorable balance between mechanical performance and fire-retardant efficiency, showing a visually more continuous char coverage while maintaining acceptable bonding properties. High-temperature furnace–FTIR analysis indicated that excessive EG loading or high-expansion-ratio EG increased CO₂ and CO-related signals at 400–700 °C, probably because of a visually looser char morphology, structural disruption during expansion, and gas release from EG intercalating agents. Although the tested panels did not fully meet the CNS Grade 3 fire-retardant requirement, the results provide a useful basis for the modification and performance optimization of halogen-free fire-retardant wood-based composite panels. Full article

Cryptomeria japonica (Japanese cedar) is extensively planted as windbreaks in Jeju, Korea, producing highly allergenic pollen that significantly affects local populations. This study analyzed 10-year trends of airborne C. japonica pollen concentrations and their relationship with meteorological factors in Jeju to provide essential data for allergy management and climate adaptation strategies. Daily airborne pollen sampling was conducted using Burkard traps from 2015 to 2024 at a monitoring site in Jeju. Meteorological data, including temperature, wind speed, relative humidity, precipitation, solar radiation, and cloud amount, were obtained from the Korea Meteorological Administration. Temporal trends were analyzed using linear regression and the Mann–Kendall test, while correlations between pollen parameters and meteorological variables were calculated using Spearman’s correlation coefficients. Over the 10-year period, annual pollen integral (APIn) and peak concentrations showed statistically significant increasing trends. Pollen season start dates demonstrated a tendency toward earlier occurrence. Season onset was strongly negatively correlated with pre-season temperatures in January and February. January solar radiation showed positive correlations with both season end and period duration. C. japonica pollen concentrations in Jeju demonstrate significant increasing trends with earlier seasonal onset, primarily driven by pre-season warming in January and February. These changes may lead to prolonged allergen exposure periods, necessitating enhanced public health preparedness and adaptation of clinical management strategies for allergic populations. Full article

The interaction between airborne allergens and environmental microplastics is an emerging concern in the context of increasing plastic pollution and allergic disease prevalence. In this study, we investigated the molecular interaction between Cry j 1, the major allergen of Japanese cedar (Cryptomeria japonica) pollen, and polyethylene terephthalate (PET) microplastic surfaces using all-atom molecular dynamics simulations integrated with computational epitope selection analyses. The simulations showed that Cry j 1 adsorbs onto PET primarily through hydrophobic and van der Waals interactions, with residues Pro165, Ala227, Tyr228, and Val163 contributing prominently to surface association. Mapping of selected epitope regions indicated that several linear B-cell epitopes remained solvent exposed following adsorption, whereas two CD4⁺ T-cell epitope regions (T5 and T6) contributed more directly to PET interaction. PET adsorption was accompanied by moderate changes in conformational dynamics, including reduced residue-level flexibility and localized secondary-structure adjustments, while the overall protein fold remained structurally stable throughout the simulation. Small decreases in radius of gyration and solvent-accessible surface area suggested mild adsorption-associated compaction rather than major unfolding. These findings indicate that PET association can influence the structural dynamics and interfacial behavior of Cry j 1 without extensive disruption of its global architecture. Because the study is entirely computational, the immunological implications remain hypothetical and require experimental validation. Nevertheless, this work provides a molecular-level framework for understanding how airborne microplastics may influence allergen behavior and protein-surface interactions in polluted atmospheric environments. Full article

In addition to the true cedars (Cedrus species), there are several genera of trees commonly called “cedar”, including species of Callitropsis, Calocedrus, Cedrela, Chamaecyparis, Cryptomeria, Cupressus, Juniperus, Thuja, and Widdringtonia. The wood essential oils (cedarwood oils) of these trees have been used as flavor and fragrance materials, as well as in medicinal applications. In this study, we present summaries of the wood essential oils from trees known as “cedar”. A literature search was carried out on cedarwood oils and, when available, compared with commercial wood essential oils from the Aromatic Plant Research Center (APRC) collection. Cedrus wood oils are generally dominated by the himachalenes and atlantones. Sesquiterpenoids are abundant in other cedarwood oils, including cedrenes, cedrol, and thujopsene in Cupressus funebris, Juniperus ashei, and Juniperus virginiana. Cadinane sesquiterpenoids are generally abundant in Cedrela odorata and Cryptomeria japonica, while nootkatane sesquiterpenoids are found in Callitropsis nootkatensis and eudesmane sesquiterpenoids are found in Thuja occidentalis. Sesquiterpenoids are generally responsible for the woody fragrances of cedarwood oils, but monoterpenoids can also be dominant (e.g., Calocedrus species). Full article

The influence of forest type on soil aggregates distribution, stability, and the contribution of aggregate-associated carbon (C) to bulk soil organic carbon (SOC) remains poorly understood. This may be crucial for the accumulation and persistence of SOC in subtropical ecosystems. In this study, we examined soil aggregate distribution and stability at two depths (0–15 and 15–30 cm) in 10-, 20-, and 30-year-old Cryptomeria japonica (Japanese cedar) and Chimonobambusa quadrangularis (square bamboo) plantations. We further assessed the contribution of carbon (C) associated with distinct aggregate fractions to bulk SOC. Across all stand ages and soil depths, macroaggregates accounted for 19%–56% of total soil aggregates in Japanese cedar plantations, whereas their proportion was 30%–337% higher in square bamboo plantations. In contrast, fine aggregates constituted 3%–67% of total aggregates in Japanese cedar plantations, but were 29%–94% lower in square bamboo plantations than in Japanese cedar plantations. Compared with Japanese cedar plantations, aggregate mean weight diameter (MWD) and geometric mean diameter (GMD) increased by 17%–88% and 35%–152%, respectively, in square bamboo plantations. In Japanese cedar soils, C and nitrogen (N) were primarily concentrated in coarse macroaggregates and fine macroaggregates, whereas in square bamboo plantations, C and N were mainly associated with coarse macroaggregates only. Both aggregate-associated soil C and N varied significantly with aggregate size and forest type, and Japanese cedar soils exhibited higher aggregate C/N ratios, particularly in older stands. Bulk SOC was positively correlated with macroaggregate-associated C in both forest types and with the silt and clay fractions in Japanese cedar plantations. MWD increased with higher macroaggregate C content and declined as the proportion of C in smaller aggregate fractions increased. These findings indicate that forest type plays a critical role in regulating soil aggregation and SOC stabilization pathways, with square bamboo plantations enhancing C sequestration by promoting macroaggregate formation and stability. Full article

Monitoring stem sap flow is essential for understanding plant water-use strategies and eco-physiological processes in the ecologically fragile karst region. In the study, we continuously monitored four co-occurring species—Cryptomeria japonica var. sinensis (LS), Liquidambar formosana (FX), Camptotheca acuminata (XS), and Melia azedarach (KL)—using the thermal dissipation probe method in a karst farmland-to-forest restoration area. We analyzed diurnal and nocturnal sap flow variations across different growth periods and their responses to environmental factors at an hourly scale. The results showed (1) A “high daytime, low nighttime” sap flow pattern during the growing season for all species. (2) The proportion of nocturnal sap flow was significantly lower in the growing than in the non-growing season. (3) Daytime sap flow was primarily driven by photosynthetically active radiation (PAR) and vapor pressure deficit (VPD) during the growing season. In the non-growing season, daytime drivers were species-specific: relative humidity (RH, 39.39%) for LS; air temperature (Ta, 23.14%) for FX; PAR (33.03%) for XS; and soil moisture at a 10 cm depth (SM1, 25.2%) for KL. Nocturnal flow was governed by VPD and RH during the growing season versus soil moisture (SM1 and SM2) and RH in the non-growing season. These findings reveal interspecific differences in water-use strategies and provide a scientific basis for species selection and afforestation management in the karst ecological restoration of this research area. Full article

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

The growing worldwide demand for essential oils (EOs) brings new opportunities for Azorean Cryptomeria japonica aerial parts waste valorization. Therefore, the phytochemical and bioactivity investigation of EOs from different Azorean C. japonica tissues, such as twigs (Az–CJT), remains imperative to add more value to C. japonica’s EO industry, alongside the contribution to the local sustainable circular bioeconomy. This study provides, for the first time, GC–MS analysis and brine shrimp toxicity of the EO hydrodistilled from Az–CJT and aims to compare these parameters with those determined for a commercial Azorean C. japonica (branches and foliage) EO obtained through steam distillation. The main Az–CJT EO components were α-eudesmol (19.53%), phyllocladene (14.80%), elemol (12.43%), nezukol (11.34%), and γ-eudesmol (5.32%), while α-pinene (28.62%), sabinene (24.30%), phyllocladene (5.10%), β-myrcene (5.09%), and limonene (4.93%) dominated in the commercial EO. Thus, Az–CJT EO exhibited the highest sesquiterpenoids (43.52%), diterpenes (20.85%), and diterpenoids (13.21%) content, while the commercial EO was dominated by monoterpenes (74.61%). The Az–CJT EO displayed significantly higher toxicity than the commercial EO, with mortality rates of 87.7% and 16.9%, respectively, at 100 µg/mL. This result is likely related to the substantially higher terpenoid content of Az–CJT EO (61.20% vs. 9.44%), largely attributed to the sesquiterpenoid fraction. Due to its distinct chemical profile, Az–CJT EO may have differential commercial applications, warranting further investigation into its bioactive value and safe use. In conclusion, this study adds knowledge on the potentialities of C. japonica aerial parts’ EOs from the Azorean region. 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