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Nematode communities in natural pristine forests composed of trees aged over 1000 years have not been thoroughly studied. Old-growth forests can provide diverse microhabitats for nematodes such as fallen trees with mossy conditions. This study aimed to characterize the community and trophic compositions of nematodes in relation to different microhabitats in old-growth Japanese cedar (Cryptomeria japonica (L. f.) D. Don) forests in Yakushima Island, Japan. To this aim, nematodes retrieved from four different types of microhabitats were morphologically identified at the family/genus level and divided into five trophic groups. A nonmetric multidimensional scaling scatterplot showed that nematode communities clustered significantly in each microhabitat and their community compositions were significantly affected by C/N ratio. With respect to nematode trophic composition, bacterivorous nematodes dominated decaying barks of fallen trees, with a relative abundance of 45%, while fungivorous nematodes were dominant in living barks of cedar trunks (61%). Predatory–omnivorous nematodes predominated in mosses of fallen trees (51%). These results showed that nematode community and trophic composition were different among microhabitats characterized by nutrient conditions. The predatory–omnivorous nematodes were abundant in mosses with N-rich conditions. In contrast, fungivorous nematodes were abundant in cedar trunks with high C/N conditions. Thus, old-growth natural forests can provide diverse microhabitats where various nematode taxa coexist due to the presence of fallen trees and mosses. [ABSTRACT FROM AUTHOR]

Background: Pediatric allergic rhinitis (AR), including cedar pollinosis (CP), is increasing in Japan. We investigated the effects of sublingual immunotherapy (SLIT), which has limited studies of its effectiveness in real‐world settings, on children with CP. Methods: This retrospective cohort study used a claim database in 2018–2021. Children aged ≤15 years with CP records in 2019 were eligible and were followed up through 2021. We included 2962 CP children undergoing SLIT and 547 who were not. The medication score was used to evaluate SLIT effectiveness in the cedar pollen dispersal season each year. Adverse events and the occurrence of allergic diseases were also evaluated. Results: Medication score was higher in the SLIT group during the index period but lower in 2021 compared to the non‐SLIT group (mean ± standard deviation: 5.17 ± 2.39 and 4.74 ± 2.38 in 2019, 3.13 ± 2.30 and 3.55 ± 2.48 in 2021, respectively). The adjusted mean difference between groups from 2019 to 2021 was −0.62 (95% confidence interval: −0.86 to −0.39, p <.0001), and the medication score was reduced in the SLIT group (risk ratio: 1.2: 1.1 to 1.3). The occurrence of adverse events involving abdominal disorders (adjusted odds ratio [aOR]: 0.64: 0.51 to 0.81), asthma exacerbation (aOR: 0.37: 0.24 to 0.57), and allergic diseases involving hay fever unrelated to CP (aOR: 0.60: 0.45 to 0.80) or asthma (aOR: 0.71: 0.58 to 0.86) was lower in the SLIT group. Conclusion: In children with CP, SLIT is effective, well tolerated, and could decrease the occurrence of other allergic diseases. [ABSTRACT FROM AUTHOR]

Deadwood in forests plays a critical role in maintaining the ecological functions. Small mammals use deadwood, and thus deadwood can mitigate the negative impacts of plantation on small mammals. This study focused on fallen dead trees in planted forests, and aimed to verify whether fallen dead trees affect behavioral patterns of Japanese squirrels. To clarify the use of fallen dead trees by Japanese squirrels in a Japanese cedar plantation, we observed squirrel behavior by camera trap surveys at 61 survey sites. Our findings showed that fallen dead trees play a crucial role in the behavior of Japanese squirrels, serving as landmarks for movement, vigilance, resting, and hoarding sites. These functions are critical for the survival of Japanese squirrels, suggesting that fallen dead trees in planted forests have positive impacts on their microenvironment use. The increase of deadwood due to disturbances such as heavy rainfall and snowfall resulting from climate change may provide benefits to arboreal small mammals in poorly managed planted forests. Additionally, leaving some of the deadwood generated during the harvesting process in properly managed forests can improve the quality of habitat for arboreal small mammals. [ABSTRACT FROM AUTHOR]

In this study, we determine whether coniferous plantations in the cool temperate zone of northeast Japan, with few natural evergreen forests, can serve as a habitat for Japanese squirrels. We also examine whether Japanese squirrel habitat use in cedar plantations varies based on forest structure. Our results showed that the relative frequency of squirrel occurrence, determined by camera traps and the number of feeding signs, was significantly higher at cedar forest survey sites than other forest types. The best generalised linear model for frequency of occurrence included the number of standing trees, canopy openness and understory visibility, while the best model for the number of feeding signs included total basal area, canopy openness and the number of walnut trees. The results suggest that cedar plantations within the study area serve partially as a habitat for squirrels, replacing natural evergreen trees. Furthermore, squirrel habitat use differed between cedar plantations based on forest structure, confirming the importance of a diverse forest structure for squirrels. Therefore, when considering the conservation and management of small arboreal mammals that use such plantations, they must include diverse structures to facilitate their use as a habitat. [ABSTRACT FROM AUTHOR]

Cedar pollinosis in Japan affects nearly 25 % of Japanese citizens. To develop a treatment for cedar pollinosis, it is necessary to understand the relationship between the time of its occurrence and the amount of airborne cedar pollen. In the spring of 2009, we conducted daily Internet-based epidemiologic surveys, which included 1453 individuals. We examined the relationship between initial date of onset of pollinosis symptoms and daily amount of airborne cedar pollen to which subjects were exposed. Approximately 35.2 % of the subjects experienced the onset of pollinosis during a one-week interval in which the middle day coincided with the peak pollen count. The odds ratio for this one-week time interval was 4.03 (95 % confidence interval: 3.34–4.86). The predicted date of the cedar pollen peak can be used to determine the appropriate date for initiation of self-medication with anti-allergy drugs and thus avoid development of sustained and severe pollinosis. [ABSTRACT FROM PUBLISHER]

Highlights: [•] We obtained reliable estimations of water use components in Japanese cedar stands. [•] We found a constant ratio of interception to rainfall (P) throughout a year. [•] Upper canopy transpiration contributes to total water use during scarce rainfall. [•] These result in a conservative ratio of evapotranspiration to P throughout the year. [ABSTRACT FROM AUTHOR]

Highlights: [•] Physical process of canopy interception loss remains to be explained. [•] Rainfall partitioning to interception was similar between the stands. [•] The rate of interception increased with rainfall intensity. [•] Observed amount of interception was greater than estimated amount of evaporation. [•] We suggest that splash droplets transport by canopy ventilation is the primary process of interception loss. [ABSTRACT FROM AUTHOR]

The vibrational properties of Japanese cedar wood at high temperature were measured. The specimen, its support system, a magnetic driver, and a deflection sensor were placed in an electric drying oven, where vibration tests were conducted. The heating temperatures ranged from 25 ºC to 200 ºC in 25 ºC increments. The resonance frequency decreased with higher heating temperature and decreased most dramatically in the temperature range of 150 ºC to 200 ºC. The loss tangent had a minimum value at 100 ºC and changed more in the temperature range from 150 ºC to 200 ºC than in the range from 25 ºC to 150 ºC. The changes in the resonance frequency and loss tangent of the specimens with larger distance from the pith (d) were smaller than those around the pith. These tendencies are believed to have occurred because the portion with a larger d had a smaller number of intercellular layers than the portion around the pith. [ABSTRACT FROM AUTHOR]

Background Patients allergic to pollen have been known to become more symptomatic during pollen season compared with the nonpollen season. However, there are few studies regarding whether higher exposure to pollen might increase the prevalence of allergic diseases. Methods An ecological analysis was conducted to evaluate whether pollen exposure is associated with the prevalence of allergic diseases in schoolchildren. Pollen count data of Japanese cedar ( Cryptomeria japonica) and Japanese cypress ( Chamaecyparis obtusa), which are the major pollen allergens in Japan, were obtained from each prefecture. The prevalence of allergic diseases in schoolchildren in each prefecture was based on a nationwide cross-sectional survey using the International Study of Asthma and Allergies in Childhood questionnaire. Results After omitting three prefectures where pollen data were not available, data of 44 prefectures were analysed. The prevalence of allergic rhinoconjunctivitis in children aged 6-7 years was positively associated with both cedar and cypress pollen counts ( P = 0.01, both), whereas the prevalence of allergic rhinoconjunctivitis in children aged 13-14 years was positively associated with only cypress pollen counts ( P = 0.003). Furthermore, the prevalence of asthma was positively associated with cedar pollen counts in 6- to 7-year-old children ( P = 0.003) but not cypress pollen counts in either age group. Conclusions There are ecological associations between pollen counts and the prevalence of allergic diseases in Japanese schoolchildren. Further studies are needed to determine whether the difference between the effects of cedar and cypress pollens is attributable to pollen counts or allergenicity. [ABSTRACT FROM AUTHOR]

Abstract: In the areas adjacent to Kyoto, an ancient capital of Japan, the regional vegetation is mostly secondary forest. In order to reconstruct the fire and vegetation history of the area and to estimate when and how the secondary forest was established, peat cores were obtained from a small basin in the western Tamba Highlands, 35-km northwest of Kyoto city. Pollen, plant macrofossil and charcoal records from the site indicate that the cool-temperate forest characterized by beech (Fagus crenata) with Japanese cedar (Cryptomeria japonica) developed in the middle Holocene (c. 4700–2400 cal BP). Forest fires were rare during this period. In the late Holocene, charcoal data indicate that at least two major fire events occurred. Following a fire c. 2500 cal BP, the vegetation changed from beech-dominated cool-temperate forest with Japanese cedar to a forest with less beech and increased pine. The next conspicuous fire took place at c. 900 cal BP, after which the vegetation shifted to a deciduous oak and pine-dominated forest, similar to the present vegetation around the site. The Gramineae pollen percentage was continuously high since the second fire event, suggesting that grassland was maintained. In the western Tamba Highlands, secondary forests were established during the eleventh century, but resource depletion was less serious and open secondary forest has been maintained by human activities. [Copyright &y& Elsevier]

Purpose: Although cross-sectional studies have reported that the prevalence of allergy is reduced on a farm, few prospective studies were carried out on adults. We examined the association of experience of farming with occurrence of cedar pollinosis in a prospective cohort in Japan. Methods: A total of 5,698 men and 6,533 women, aged 35 to 69 at baseline in 1992, participated in the Takayama Study, a population-based prospective cohort study. Occupational history was assembled via a self-administered baseline questionnaire. To obtain information on cedar pollinosis, a follow-up questionnaire after 10 years from baseline was administered in 2002. Results: Compared with nonfarmers, farmers had a significantly reduced risk of cedar pollinosis after controlling for covariates (hazard ratio (HR): 0.61, 95% confidence interval (CI): 0.41, 0.90 in men; and HR: 0.31, 95% CI: 0.16, 0.60 in women). There was no significant association of cedar pollinosis with other occupations except for an increased risk of pollinosis among salesmen in multivariate analyses. We observed that other occupational exposures were not associated with the onset of cedar pollinosis after adjusting by covariates, except for a decreased risk of cedar pollinosis for woodworking in men. Conclusions: These data suggest that exposures related to farming environment might be protective against cedar pollinosis. [ABSTRACT FROM AUTHOR]

Abstract: Although the excess of lead-210 (210Pbex) has been described as an alternative or complementary nuclide to cesium-137 (137Cs) for soil erosion assessment, the potential use of 210Pbex in forested environments has not been examined sufficiently. In this study, to investigate the potential use of 210Pbex for the assessment of soil erosion on various forested hillslopes, we compared soil erosion rates derived from 210Pbex to those from 137Cs obtained in forest stands. The study was conducted in four types of forest: a Japanese cypress stand with a bare forest floor, a Japanese cypress stand with a fern understory, a Japanese cedar stand with sufficient litter cover, and a natural broadleaf forested stand in the Tsuzura River basin of southeastern Japan. 137Cs and 210Pbex inventories for seven potential reference sites on flat ridge tops and along transects in each stand were measured using gamma-ray spectrometry to calculate soil erosion rates. To describe the behavior of organic matter in each stand, the amounts of eroded sediment and organic matter were observed for approximately 2years in erosion plots (1.7–2.0m long, 0.5m wide) in the Japanese cypress stand (bare), Japanese cedar stand, and broadleaf forest stand. From the preliminary assessment of potential reference sites, spatial variability in 210Pbex was comparable to that of 137Cs. Mean erosion rates estimated from both Cs and Pb were highest in the Japanese cypress stand (bare), followed by the Japanese cypress stand (fern), the broadleaf forest stand, and the Japanese cedar stand. This magnitude relationship was consistent with that of observation results of eroded sediment in erosion plots. In the Japanese cypress stand (bare), a significant correlation was found between Cs- and Pb-based soil erosion rates in the Japanese cypress stand (bare) while no significance was found in the other three stands. These results provide evidence of the feasibility of 210Pbex for soil erosion assessment in forest stands with bare forest floors. In the other three stands, the preferential loss of 210Pbex associated with organic matter may explain the poor correlation between the two erosion rates. [Copyright &y& Elsevier]

Quantification of carbon budgets and cycling in Japanese cedar ( Cryptomeria japonica D. Don) plantations is essential for understanding forest functions in Japan because these plantations occupy about 20% of the total forested area. We conducted a biometric estimate of net ecosystem production (NEP) in a mature Japanese cedar plantation beneath a flux tower over a 4-year period. Net primary production (NPP) was 7.9 Mg C ha−1 year−1 and consisted mainly of tree biomass increment and aboveground litter production. Respiration was calculated as 6.8 (soil) and 3.3 (root) Mg C ha−1 year−1. Thus, NEP in the plantation was 4.3 Mg C ha−1 year−1. In agreement with the tower-based flux findings, this result suggests that the Japanese cedar plantation was a strong carbon sink. The biometric-based NEP was higher among most other types of Japanese forests studied. Carbon sequestration in the mature plantation was characterized by a larger increment in tree biomass and lower mortality than in natural forests. Land-use change from natural forest to Japanese cedar plantation might, therefore, stimulate carbon sequestration and change the carbon allocation of NPP from an increment in coarse woody debris to an increase in tree biomass. [ABSTRACT FROM AUTHOR]

Background: Pollinosis induced by the cedar pollen antigen is the most common seasonal allergic reaction in Japan. We aimed to examine the relationship between smoking and risk of cedar pollinosis in a population-based cohort of the Japanese. Methods: Study subjects were 12,221 men and women from the Takayama Study cohort who were 35–69 years old at enrollment in 1992. A follow-up survey in 2002 was used to obtain information about four symptoms related to cedar pollinosis. Results: A total of 1,000 subjects had cedar pollinosis during the 10-year follow-up. As compared with those who had never smoked, current smokers at the baseline were at a significantly decreased risk of cedar pollinosis after controlling for covariates in men (hazard ratio [HR]: 0.64, 95% CI: 0.50–0.83) as well as in women (HR: 0.64, 95% CI: 0.47–0.88). There was a significant dose-response relationship between the risk of cedar pollinosis and the number of cigarettes smoked each day as well as with the number of years an individual had smoked. A significant risk reduction was observed among men and women who had continued to smoke cigarettes during the follow-up period in comparison with those who had never smoked. There was no risk increase for former smokers at the baseline as well as for those who quit smoking during the follow-up. Conclusions: Some components of tobacco may protect against cedar pollinosis. Our finding could provide clues about therapeutic strategies for protection against cedar pollinosis. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: The first enantioselective synthesis of (1S,3R,6R)-1-hydroxy-7(14),10-bisaboladien-4-one, a potent antifeedant isolated from the Japanese cedar, Cryptomeria japonica, was achieved starting from methyl (R)-4-hydroxy-3-methylbutanoate via a stereoselective carbonyl ene cyclization reaction as the key step. Comparison of the spectral data and specific rotation of the synthetic material with those of the natural product led to unambiguous stereochemical assignment of the antifeedant as 1S, 3R, and 6R. [Copyright &y& Elsevier]

Background: A pollen exposure chamber (OHIO Chamber) was built in central Tokyo, Japan, in order to study seasonal allergic rhinitis (SAR). Since satisfactory outcomes were obtained from the controlled pollen exposure at the chamber, we conducted preliminary studies in volunteers with SAR. Methods: Ten volunteers with SAR sensitive to Japanese cedar (JC) pollen were enrolled in this study. In order to investigate the intranasal and intraocular pollen number, volunteers were initially exposed to a low concentration of JC (2500 grains/m³) for at most 1 hour in this chamber. Before and after the exposure, nasal cavities and eyes were washed with 100 ml and 25 ml of saline, respectively. Nasal and eye washing solutions were collected and the number of JC pollen was counted. After 3 hours the volunteers were subsequently exposed to a moderate concentration of JC (4500 grains/m³) for 2 hours. Subjective nasal and ocular symptoms were recorded and the amount of nasal secretion was measured during the allergen exposure periods. Results: During the initial exposure, all volunteers except one stayed in the chamber for 1 hour without any nasal or ocular symptoms. The number of pollen in the nose and eyes was 249.2 ± 120.9 and 13.6 ± 13.6 grains, respectively. During the subsequent 2-hour exposure to JC pollen, nasal and ocular symptoms developed gradually in a time dependent manner in all the volunteers except one. Conclusions: This is the first clinical study using Japanese cedar pollen under well-controlled conditions in the OHIO chamber in which the induction of allergic symptoms was observed. The OHIO chamber will be useful for studying allergic rhinitis in Japan. [ABSTRACT FROM AUTHOR]

Abstract: The contaminants adsorbed on the surface of pollen may affect the development of hay fever, because the patients of the fever are larger in areas with much air pollution than in nonpolluted areas and the fine particles and gases are susceptible to deposit on the nasal cavities and eyes by their transfer on the pollen. Since Japanese cedar pollinosis is the most common hay fever in Japan, we analyzed the air pollutants adsorbed on the surface of dispersed Japanese cedar pollen in the urban and mountainous districts. Fine anthropogenic particles were significantly adsorbed and many elements were concentrated on the surface of the pollen in the urban site of Yokohama, while they were not concentrated on the surface of the pollen collected at a mountainous site. The acid gases are also adsorbed and acidify the surface, and their amounts increase with their concentrations in the ambient air. The high adsorption of nitric acid on the pollen determined by an exposure experiment of nitric acid gas suggests that nitric acid is dissolved in the inner part of the pollen. The adsorption amounts of the gases on the pollen were especially greater than those on other natural particles, humic acid and yellow sand. [Copyright &y& Elsevier]

Cedar sample was collected at the black rain area in Nagasaki city. A clear peak of 90Sr/Sr was observed in the 1924-1925 rings. To investigate the mobility of Sr in a cedar tree stem, strontium chloride solution was injected into a living tree, and the distribution profiles of Sr in the stem at 8 months later were determined. The strontium moves radially through the sapwood of a cedar stem but that it almost stops at the heartwood. It was concluded that the peak in the 1924-1925 rings was due to the black rain from the Nagasaki atomic bomb. [ABSTRACT FROM AUTHOR]

The article evaluates the effects of Lactobacillus acidophilus strain on the symptoms of Japanese cedar-pollen allergy. The placebo-controlled, single-blind study was carried out during the 2002 and 2003 seasons of Japanese cedar pollination. The data show that a daily oral intake of milk fermented Lactobacillus acidophilus cells improved the symptoms of Japanese cedar pollinosis.

Soil carbon cycling was studied in Japanese cedar plantations with different stand ages after clear-cutting and was analyzed by a compartment model. The amount of biomass and the litterfall rate increased rapidly with the growth of Japanese cedar, which were approximated by a simple logistic function of stand age. The accumulation of A0 layer decreased from 21 t ha−1 to 5 t ha−1 during the 10 years following clear-cutting, and then recovered to nearly the same level as before clear-cutting within 20 years after clear-cutting, although the amount of soil carbon in the mineral soil recovered more than 40 years after clear-cutting. The total and mineral soil respiration rates increased rapidly after clear-cutting and gradually decreased in young stands and stabilized in old stands. The relative decomposition rate of the A0 layer and organic matters in mineral soil was high in the young stands because of the relatively high soil temperature rather than the soil moisture content. After the closing up of the canopy, the relative decomposition rates of the A0 layer and humus in the mineral soil stabilized at 0.14 to 0.16 y–1 and 0.005 to 0.013 y−1, respectively. Consequently, soil carbon cycling was strongly affected by clear-cutting. The amount of soil carbon rapidly decreased because of the cessation of litterfall and the increase of the relative decomposition rate of the A0 layer and humus, and recovered gradually to the level before clear-cutting with the growth of the cedar plantation. The change in soil carbon cycling with stand development was partly caused by the change in soil temperature and moisture content but was mainly caused by the amount of cedar litterfall which changed significantly in the early stage of the stand following clear-cutting, and became slower and leveled off in the late stage with stabilization of the environmental conditions and litterfall rate. [ABSTRACT FROM AUTHOR]

Abstract This study examined the effects of snowfall on the beginning day of Cryptomeria japonica pollen release and predicted it under global climate change. We used a statistical method in order to investigate when the pollen release would start and how much sooner it would be, by using data on predicted meteorological conditions under global warming in Yamagata City, Japan. Estimation accuracy was improved by multiple regression by using the mean air temperature from January to February and snowfall depth in February. Adding snowfall depth yielded more accurate estimates of the beginning day of pollen release than using air temperature alone. It is possible that the effects of heat insulation and cooling by snow delay the flowering day. Under the predicted global climate change, we expect the beginning day of pollen release to become earlier in Yamagata City. The date would be 8 February in approximately 100 years, compared with 20 February at the earliest now. Eighty years from now the date could be earlier than any date recorded so far. [ABSTRACT FROM AUTHOR]

Increases in 14C concentrations in tree rings could be attributed to cosmic-ray events, as have increases in 10Be and nitrate in ice cores. The record of the past 3,000 years in the IntCal09 data set, which is a time series at 5-year intervals describing the 14C content of trees over a period of approximately 10,000 years, shows three periods during which 14C increased at a rate greater than 3‰ over 10 years. Two of these periods have been measured at high time resolution, but neither showed increases on a timescale of about 1 year (refs 11 and 12). Here we report 14C measurements in annual rings of Japanese cedar trees from ad 750 to ad 820 (the remaining period), with 1- and 2-year resolution. We find a rapid increase of about 12‰ in the 14C content from ad 774 to 775, which is about 20 times larger than the change attributed to ordinary solar modulation. When averaged over 10 years, the data are consistent with the decadal IntCal 14C data from North American and European trees. We argue that neither a solar flare nor a local supernova is likely to have been responsible. [ABSTRACT FROM AUTHOR]