Cryptomeria Research Articles

Are calibrations of sap flow measurements based on thermal dissipation needed for each sample in Japanese cedar and cypress trees?

Are calibrations of sap flow measurements based on thermal dissipation needed for each sample in Japanese cedar and cypress trees?

Survival and growth of Japanese cedar (Cryptomeria japonica) planted in tree shelters to prevent deer browsing: a case study in southwestern Japan

ABSTRACT Tree shelters are used in forestry to prevent large herbivores from browsing on young trees. Although tree shelters can generally prevent browsing damage while the young trees are within the tree shelters, they have been observed to fail in some cases. In this study, to clarify the protective capacity of tree shelters against damage due to deer browsing, the condition of tree shelters on planted Japanese cedar (Cryptomeria japonica) seedlings 2 to 7 years after installation was investigated at 42 sites in southwestern Japan where the density of sika deer (Cervus nippon) is high. The results showed that tree shelters failed for three reasons. Firstly, the shelter had collapsed or incline and could no longer protect the saplings within. Secondly, the saplings in the shelters died relatively shortly after they were planted. Thirdly, and possibly most importantly, the saplings are browsed upon by deer after they extended beyond the top of the shelter. Since there was no correlation between the damage rate and the number of years after planting, it is likely that the damage occurred immediately after the young trees protruded form the shelter. Shelters with a height of only 140 cm, which are widely used in Japan, may be too short to completely prevent herbivory damage by deer.

Tensile Examination and Strength Evaluation of Latewood in Japanese Cedar.

With the crisis awareness of global warming and natural disasters, utilization of local wood has drawn increasing attention in achieving the Sustainable Development Goals (SDGs). It is necessary to investigate the deformation and fracture of the structural tissue in wood in order to improve the safety and reliability of wood application. However, deformation and fracture mechanisms of the structural tissue in each annual ring are unknown. The mechanical characteristics of wood are reflected in the properties of earlywood and latewood. In the present study, microstructural observation and tensile tests were conducted to examine the relationship between the mechanical properties and fracture behavior of latewood in the growth direction in Japanese cedar. Brittle fracture behavior of the latewood specimen was confirmed based on the tensile stress–strain curve and features of the fracture surface. Moreover, two fracture modes, tensile fracture and shear fracture, were recognized. Weibull analysis of tensile strength in each fracture mode was performed to evaluate the reliability and utility of brittle latewood. Lastly, two fracture mechanisms were discussed based on the failure observation findings by a scanning electron microscope.

Individual-level distance-independent-based growth and yield prediction models for long-term Japanese cedar (Cryptomeria japonica)

Yield prediction has been determined to be vital in sustainable forest management. Recently, research trends have shifted from stand-level to individual-level yield prediction. In this study, we examined the effectiveness of yield prediction models based on a distance-independent approach for Japanese cedar (Cryptomeria japonica (L.f.) D.Don) trees in western Japan. We further examined the accuracy of the models with reference to existing data collected over the long-term. First, we constructed distance-independent height, diameter growth, and survival models. Then, we simulated for approximately 50 years individual tree height, diameter at breast height (DBH), and volume growth using the test data. We then compared the predicted and observed values and calculated root-mean-square error (RMSE) and bias to evaluate the model accuracy. The models were noted to perform well when predicting mean height, DBH, and volume for Japanese cedar trees; in fact, they adequately predicted the diameter distribution. Our results suggest that distance-independent models could adequately predict long-term mean values and diameter distribution. However, RMSE and bias indicated that error propagation occurred over longer time spans. Thus, it is effective to conduct actual measurements at some point in the forest development phase and use the measurements as initial values for short- or medium-term predictions.

Association between corticolous myxomycetes and tree vitality in Cryptomeria japonica.

The bark of live trees provides an important microhabitat for corticolous myxomycetes. However, the association between the presence of myxomycetes and health of host trees has not been studied in detail. In this study, we aimed to investigate the relationship between tree vitality and myxomycetes on the bark of Cryptomeria japonica trees in a montane forest in western Japan. The vitality of trees was categorized into four grades based on the visual assessment of tree shape and leaf density in the upper branches. Myxomycetes on the bark surface were examined using the moist chamber culture method. A decline in tree vitality increased bark pH and decreased electrical conductivity of the bark exudates. Seventeen myxomycete species were recorded in 74 C. japonica trees. The structure of myxomycete communities varied between healthy and unhealthy trees, and species diversity increased as the vitality declined. The relative abundance of Cribraria confusa decreased as the vitality declined, while that of Paradiacheopsis solitaria increased. The results showed that acidophilic myxomycetes grew on healthy C. japonica bark, but changes in bark pH associated with vitality decline led to the weakening of acidity and shifted the community structure; thus, corticolous myxomycete diversity was enhanced as tree vitality decline.

Cellular-level in planta analysis of radial movement of minerals in a konara oak (Quercus serrata Murray) trunk

After the Fukushima Daiichi Nuclear Power Plant accident, radiocesium, one of the main radioactive materials, has been accumulated inside konara oak trunks. Radiocesium has been thought to move radially through the trunk, but it has not been scientifically vindicated because the mechanism of the radial movement of minerals has not yet been experimentally determined. In this study, mineral radial movement was investigated in konara oak trunks of standing trees. A stable isotope cesium (Cs) solution was injected as a tracer into the outer sapwood of standing konara oak tree trunks. A trunk part was subsequently freeze-fixed with liquid nitrogen and subjected to Cs distribution analysis using cryo-scanning electron microscopy/energy-dispersive X-ray spectroscopy. By comparing normal samples that included living cells and freeze–thaw treated samples that contained no living cells, it was concluded that the injected Cs has been moving through the sapwood by the combination of rapid symplasmic movement by virtue of the living xylem parenchyma cells and slow apoplastic diffusion. Conversely, the Cs solution did not diffuse from the sapwood to the heartwood, implying that Cs is exuded from the living parenchyma cells to the apoplast, i.e., cell walls or adjoined dead parenchyma cells in the layer at the sapwood–heartwood boundary, and then diffused into the heartwood. By integrating the results of this study and our previous results obtained on Japanese cedar, we conclude that the mechanism of the radial movement of minerals through the sapwood seems to be a universal characteristic of tree species. In contrast, since mineral concentrations varied among tree species, the movement mechanism across the sapwood–heartwood boundary can differ among tree species.

The combined effects of tree shelters, large stock and vegetation control on the early growth of conifer seedlings

ABSTRACT Tree shelters are effective in enhancing early survival and growth and protecting planted seedlings against herbivory by mammals; they are, however, expensive. In order to be cost-effective, we need to employ silvicultural practices that maximize the benefits of using tree shelters. Thus, this study examined whether tree shelter effects on early seedling growth are enhanced by the combination of large stock and vegetation control, based on a three factor split-plot experiment for the first three years after planting the seedlings out in a fenced plantation of Japanese cedar (Cryptomeria japonica). Vegetation control involved spot and strip weeding to reduce labor costs. The experiment demonstrated the great effect of tree shelters on enhancing the early height growth of seedlings. At the end of the third growing season, sheltered seedlings were 1.5 times taller than unsheltered seedlings on average, and approximately two-thirds of sheltered seedlings had exceeded the browsing height of deer, while unsheltered seedlings had not. Using large stock and employing vegetation control also positively affected seedling height. However, combining these treatments with tree shelters intensified the positive effects on seedling height, and shortened the period during which the leader shoots of seedlings would be unprotected from the browsing without fencing. The present study thus reveals that the combination of tree shelters, large stock and vegetation control is effective in maximizing the benefit of tree shelter installation.

Investigation of the sensitization rate for gibberellin-regulated protein in patients with Japanese cedar pollinosis.

Pollen-food allergy syndrome (PFAS) usually manifests as an itching sensation in the mouth and throat immediately after eating fresh fruits and vegetables. However, some patients with PFAS experience systemic symptoms including anaphylaxis. In Europe, cypress gibberellin-regulated protein (GRP) has been noted to cause allergenicity and exhibit cross-reactivity with peach GRP. Japanese cedar (Cryptomeria japonica), classified in the cypress family, is the primary causative substance among all environmental allergens in Japan. However, studies on the prevalence of GRP sensitization in patients with cedar pollinosis are lacking. This study examined the prevalence of GRP sensitization in patients with Japanese cedar pollinosis. We enrolled 52 patients who had requested sublingual immunotherapy treatment with mild-to-severe rhinitis during spring, and had a JCP-specific immunoglobulin E (IgE) levels of >0.7 UA/mL. Peach GRP was purified using affinity chromatography with a monoclonal antibody column. Specific IgE levels to peach GRP were measured using an enzyme-linked immunosorbent assay. Samples exhibiting absorbance at 450 nm of over mean plus three standard deviations of the negative control value were defined as positive. Sera from three patients with severe peach allergy were used as positive controls. Eleven sera from 52 patients with JCP-induced allergic rhinitis were positive for peach GRP. Twenty percent of patients with cedar pollinosis were sensitized to peach GRP. Well-powered studies are needed to clarify whether these patients are at an increased risk for systemic symptoms or whether they primarily demonstrate only localized symptoms.

Comprehensive study of distributions of residual stress and Young\u2019s modulus in large-diameter sugi (Cryptomeria japonica) log

Aged conifer forests in Japan are expected to produce large-diameter logs, defined as logs with a top-end diameter of 30 cm or more. However, the knowledge and techniques for industrial processing of large-diameter logs of Japanese wood species have not been sufficiently developed. This study was aimed at characterizing the longitudinal component of residual stress distribution of large-diameter logs of sugi (Japanese cedar, Cryptomeria japonica), a major tree species cultivated in Japan, as the processing yield of primary lumber from large-diameter logs is affected by the magnitude and distribution pattern of the residual stress. The radial distributions of the released strain of residual stress, tensile Young’s modulus, and residual stress were measured using 63 logs. The radial distributions of the released strain and residual stress showed typical patterns reported in previous studies: contraction near the bark and elongation near the pith in the released strain, tensile stress near the bark, and compressive stress near the pith. The radial distributions of Young’s modulus showed a typical pattern: low near the pith and high near the bark. The difference between the maximum and minimum released strains in each log varied widely among individuals, which was expected to result in a wide variation in crooking when rip sawing. The longitudinal uniformity and axial symmetry of the radial distribution of the released strain and residual stress were experimentally confirmed, which lays the groundwork for improved understanding of the residual stress in sugi logs.

Trunk sap rot of Japanese cedar (Cryptomeria japonica) caused by Fomitiporella sinica

ABSTRACT Trunk rot caused by the wood decay fungus Fomitiporia torreyae is a serious disease of Japanese cedar. The rot is characterized by white sap rot with brown zone lines and vertical depressions on the trunk. During our field investigations on this disease, we found another sap rot on Japanese cedar, characterized by white rot with brown zone lines, with or without less obvious depressions on the trunk. The results of phylogenetic analysis of the most frequently isolated fungus from the diseased trees and morphological observation of basidiocarps previously identified as Fomitiporella umbrinella showed that both represented Fomitiporella sinica. Our inoculation tests using Japanese cedar showed that F. sinica caused longer discoloration in sapwood compared with control treatment. Therefore, we concluded that F. sinica was the cause of trunk rot on Japanese cedar as reported for F. torreyae, but trunk depressions were not obvious in the trees infected with F. sinica. Moreover, branch scars were found around the middle of decaying parts of diseased trees infected with F. sinica, and infection with this fungus was assumed to occur via dead branches or pruning scars.

Embedment properties of Japanese cedar (Cryptomeria japonica) treated with resin impregnation

To strengthen the embedment properties of wood, this study applied the resin impregnation technique, which fills the resin into wood cells. The urethane prepolymer and acrylic monomer were selected in this study. A mechanical test by a round steel bar loaded to the wood specimen was conducted. The characteristics showed higher values in the resin-impregnated groups than in the control specimen group, especially in the stiffness. The urethane- and acryl-impregnated group showed 3.78 and 2.27 times the stiffness values of the control groups in the parallel-loaded condition, and 1.94 and 1.24 times those of the control group in the perpendicularly loaded condition, respectively. Although the stiffness was significantly increased, there was a lack of ductility, which seems to be a serious problem for construction application.

An Improved and Simplified Propagation System for Pollen-Free Sugi (Cryptomeria japonica) via Somatic Embryogenesis.

Sugi (Japanese cedar, Cryptomeria japonica) is the most important forestry tree species in Japan, covering 44% of the total artificial forest area. Large amounts of pollen released from these forests each spring cause allergic reactions in approximately 40% of the population, which are a serious social and public health problem in Japan. As a countermeasure, there is an urgent need to reforest using male-sterile plants (MSPs; pollen-free plants); however, the production of MSPs via conventional methods is inefficient, time consuming, and requires considerable resources in terms of labor and space. In the present paper, we described an improved and simplified methodology for the efficient propagation of pollen-free Japanese cedar, combining the use of genetic markers (marker-assisted selection or marker-aided selection) for the early selection of male-sterile genotypes and the use of somatic embryogenesis (SE) for the clonal mass propagation of seedlings. We describe all the stages involved in the production process of somatic seedlings. Our results demonstrated that this methodology easily and efficiently produces MSPs with a discrimination rate of 100% in a short period of time. Production of 243.6 ± 163.6 cotyledonary embryos per plate, somatic embryo germination, and plantlet conversion frequencies of 87.1 ± 11.9% and 84.8 ± 12.6%, respectively, and a 77.6 ± 12.1% survival rate after ex vitro acclimatization was achieved. Moreover, we also describe an easy method for the collection of somatic embryos prior to germination, as well as an efficient and practical method for their storage at 5°C. Finally, a representative schedule for the propagation of pollen-free sugi somatic seedlings is presented as a reference for practical uses. This methodology will definitively help to accelerate the production of C. japonica MSPs across Japan.

HLA-DPB1*05:01 genotype is a predictive biomarker of sublingual immunotherapy response for Japanese cedar pollinosis

A predictive biomarker for sublingual immunotherapy (SLIT) efficacy is not available for patients with allergic rhinitis (AR). Amino acid changes in the allergen-binding pocket of HLA-DPB1 were associated with the development of Japanese cedar (JC) pollinosis and sensitization to JC pollen. The aim of this study was to investigate whether the HLA-DPB1 gene is associated with SLIT responsiveness in patients with JC pollinosis.

Effect of cigarette smoke on immune response to pollen allergen in the lung

Cigarette smoke (CS) is a major risk factor for pulmonary diseases. Alveolar macrophages (AM) are known to play an important role in the lung immune system. Cryptomeria Japonica pollen (CJp) is known as pollen allergen but not cleared to immune response in the lung. Also, it is not fully understood the relationship of CS and CJp on immune cells in the lung. Therefore, we investigated the effects of CS and CJp on immune cells response in the lung. Mice were exposed to CS during 10 days. The next day, mice were inhaled 600μg of CJp.

Relationship among light intensity, pigment compositions and photoinhibition in relation to rhodoxanthin accumulation in the gymnosperm Cryptomeria japonica

ABSTRACT Some gymnosperms, including Cryptomeria japonica, exhibit needle reddening caused by red xanthophyll pigment, rhodoxanthin accumulation during long-term cold acclimation. Although photoprotective role of rhodoxanthin, serves as a “sunscreen”, was proposed, the key environmental and/or physiological factors involved in rhodoxanthin accumulation remain unclear. We exposed C. japonica trees to four different light intensities (13%, 39%, 64% and 100% of full sunlight) and measured some parameters (the nocturnal de-epoxidation state [DPS: ratio of the zeaxanthin + antheraxanthin to xanthophyll cycle pigments], the β-carotene level and the maximum photosystem II efficiency [Fv/Fm]) that have been suggested to play roles in rhodoxanthin accumulation. Rhodoxanthin was synthesised from autumn to winter, and less so in spring. Light intensity related to the maximum value of rhodoxanthin on chlorophyll (Chl) basis, but not to that on FW basis, because Chl content decreased with increasing light intensity. These results indicated that rhodoxanthin accumulation was accompanied with Chl decrease. In addition, the relationship between the rhodoxanthin content and the seasonal growth temperature was different among light treatments, reflecting differences in the amount of excess light among light treatments Furthermore, the rhodoxanthin content correlated significantly with the Fv/Fm, nocturnal DPS and β-carotene level in winter. Thus, rhodoxanthin accumulates in a photoinhibitory environment occurs with a decrease in Chl content and an increase in DPS.

A New Decay Parameter Focused on the Arrangement of Cells in Radial Files of Dried Japanese Cedar after Decay from Brown-rot Fungi <i>Fomitopsis palustris</i>

A New Decay Parameter Focused on the Arrangement of Cells in Radial Files of Dried Japanese Cedar after Decay from Brown-rot Fungi <i>Fomitopsis palustris</i>

Estimation of Forest Aboveground Biomass of Two Major Conifers in Ibaraki Prefecture, Japan, from PALSAR-2 and Sentinel-2 Data

Forest biomass is a crucial component of the global carbon budget in climate change studies. Therefore, it is essential to develop a credible way to estimate forest biomass as carbon stock. Our study used PALSAR-2 (ALOS-2) and Sentinel-2 images to drive the Random Forest regression model, which we trained with airborne lidar data. We used the model to estimate forest aboveground biomass (AGB) of two significant coniferous trees, Japanese cedar and Japanese cypress, in Ibaraki Prefecture, Japan. We used 48 variables derived from the two remote sensing datasets to predict forest AGB under the Random Forest algorithm, and found that the model that combined the two datasets performed better than models based on only one dataset, with R2 = 0.31, root-mean-square error (RMSE) = 54.38 Mg ha−1, mean absolute error (MAE) = 40.98 Mg ha−1, and relative RMSE (rRMSE) of 0.35 for Japanese cedar, and R2 = 0.37, RMSE = 98.63 Mg ha−1, MAE = 76.97 Mg ha−1, and rRMSE of 0.33 for Japanese cypress, over the whole AGB range. In the satellite AGB map, the total AGB of Japanese cedar in 17 targeted cities in Ibaraki Prefecture was 5.27 Pg, with a mean of 146.50 Mg ha−1 and a standard deviation of 44.37 Mg ha−1. The total AGB of Japanese cypress was 3.56 Pg, with a mean of 293.12 Mg ha−1 and a standard deviation of 78.48 Mg ha−1. We also found a strong linear relationship with between the model estimates and Japanese government data, with R2 = 0.99 for both species and found the government information underestimates the AGB for cypress but overestimates it for cedar. Our results reveal that combining information from multiple sensors can predict forest AGB with increased accuracy and robustness.

Hardwood mixtures facilitate leaf litter decomposition and soil nitrogen mineralization in conifer plantations

Productivity in conifer plantations can be increased by hardwood mixture. However, the underlying mechanisms that govern the relationship between hardwood mixture and productivity remain poorly understood, particularly with respect to nutrient cycling. We investigated how and to what extent hardwood mixtures alter nitrogen amounts in leaf litterfall, leaf litter decomposition rates, and soil nitrogen mineralization rates in an experiment that used different thinning intensities (i.e., a non-thinned “control” group with few hardwoods, a 33%-thinned “weak” group with a small amount of hardwoods, and a 67%-thinned “intensive” group with abundant hardwoods) in a conifer Cryptomeria japonica plantation (38-year old). Most of the hardwoods were 15-year old trees that have been regenerated after the first thinning. The annual leaf litterfall amount for the conifer was highest in the control group and lowest in the intensive group, whereas the reverse was true for hardwoods, although the hardwoods’ annual leaf litterfall amount was approximately half that of conifers, even in the intensive group. Consequently, the annual amount of leaf litterfall of hardwoods and conifers combined was lowest in the intensive group. However, the total amount of nitrogen in the annual leaf litterfall of hardwoods and conifers combined did not differ according to thinning intensity, because the mass-based nitrogen concentration in the leaf litterfall of hardwoods was twice that of conifers. The leaf litter decomposition rate in hardwoods was approximately three times faster than that in conifers irrespective of thinning intensity, mainly due to the lower carbon-to-nitrogen (C:N) ratio. Thus, the total amount of nitrogen in the decomposed leaves of hardwoods and conifers combined, calculated by multiplying the total amount of nitrogen in the annual leaf litterfall of hardwoods and conifers by the decomposition rate and summing the results, was highest in the intensive group. In soil from shallow depths (0–10 cm), the nitrogen mineralization rate increased in the order of control, weak, and intensive, attributable primarily to the C:N ratio, which decreased in the same order. The results indicated that increasing the hardwood content by intensive thinning significantly enhances the availability of soil inorganic nitrogen in conifer plantations, by facilitating leaf litter decomposition and soil nitrogen mineralization. These findings indicate that hardwood mixtures can increase forest productivity by enhancing nitrogen cycling.

Accuracy assessment of real-time kinematic survey using a low-cost dual-frequency GNSS receiver in a sugi (Cryptomeria japonica) plantation forest

Accuracy assessment of real-time kinematic survey using a low-cost dual-frequency GNSS receiver in a sugi (Cryptomeria japonica) plantation forest

Feasibility of Mass Production of Laminated Veneer Lumber (LVL) from Japanese Cedar (Cryptomeria japonica) in Taiwan

Feasibility of Mass Production of Laminated Veneer Lumber (LVL) from Japanese Cedar (Cryptomeria japonica) in Taiwan