Removal of trichloroethylene from aqueous solution by pyrolyzed Japanese cedar bark

The bark of Japanese cedar (Cryptomeria japonica D. Don) was heated in an N₂ atmosphere at 300–900C for 3h to investigate the surface properties of the pyrolyzed residuces and their ability to remove trichloroethylene (TCE) from aqueous solutions. The specific surface areas (S _N) and total pore volumes (V _N) of the pyrolyzed barks steadily increased with rising pyrolysis temperature; no significant differences in the average pore diameters (D _N) were observed at higher temperatures (600–900C). The adsorption capacities of the pyrolyzed residues for TCE were determined under batch mode conditions using an aqueous solution containing 500g TCE dm^–3. The adsorption data were well fitted to the Freundlich equation. The adsorption capacity of the bark pyrolyzed at 900C was about five times larger than that of commercial activated carbon.This study was presented at the 10th International Symposium on Wood and Pulping Chemistry, Yokohama, June 1999     

Comparison of organic matter dynamics in soil between Japanese cedar (Cryptomeria japonica) forest and adjacent Japanese red pine (Pinus densiflora) forest established on flatland

In order to clarify the effects of tree species on organic matter dynamics in soil, we investigated the amount of forest floor material, leaf litter decomposition rate, soil chemical characteristics, soil respiration rate and cellulose decomposition rate in a Japanese cedar forest (cedar plot) and an adjacent Japanese red pine forest (pine plot) established on a flatland. The amount of forest floor material in the cedar plot was 34.5 Mg ha⁻¹ which was greater than that in the pine plot. Because the leaf litter decomposition rate was higher in the pine plot than in the cedar plot, it is likely that the difference in the amount of forest floor material between the plots is caused by the difference in the leaf litter decomposition rate. The C concentrations of soil in the cedar plot were 1.2–2.1 times higher than those in the pine plot. Soil pH(H₂O)s in the cedar plot were significantly higher than those in the pine plot. The soil respiration rates and the rates of mineralized C in the cedar plot byin vitro incubation were higher than those in the pine plot. From this result, it is assumed that soil organic matter in the cedar plot was decomposed relatively faster compared with the pine plot. Furthermore, microbial activities, which were reflected as cellulose decomposition rates in the cedar plot, were higher than those in the pine plot. A part of this paper was presented at the 109th Annual Meeting of the Japanese Forestry Society (1998).     

Volatile components of Japanese cedar cultivars as repellents related to resistance to Cryptomeria bark borer

The response of the essential oils and their components toCryptomeria bark borer has been studied. The oils of inner bark and sapwood of resistant cultivars acted as a repellent toCryptomeria bark borer rather than as an attractant, whereas those of susceptible cultivars acted as an attractant.-Terpineol, nerolidol,-cadinene,-eudesmol, terpinolene, and cedrol showed high repellent activity. The relative contents of the former four compounds were larger in resistant cultivars than in sensitive cultivars. It suggests that these four compounds might be one of the causes of resistance toCryptomeria bark borer. The contents of terpinolene and cedrol were small, and these two compounds may have no or a small influence on resistance. Although some of compounds acted as attractants forCryptomeria bark borer, it was not attributable to the difference in the bark borer response of Japanese cedar because of the relatively low ratio of these compounds in each essential oil and the small differences in the ratios between resistant and susceptible cultivars.     

Mitigation of aluminum toxicity by calcium and magnesium in Japanese cedar (Cryptomeria japonica)

We investigated the short-term and long-term mitigation of Al toxicity by Ca and Mg in pot trials of Japanese cedar (Cryptomeria japonica D. Don). We found that in the initial stages of treatment, Al toxicity at high Al concentration (5mM) was mitigated by Ca and Mg through the stimulation of antioxidant enzyme activities in needles. However, growth reduction occurred after 11 months exposure to Al despite the coexistence of Ca and Mg. Growth reduction was related to Al³⁺ activity in solution rather than the concentration of Ca and Mg. Therefore, when considering the influence of soil acidification on Al toxicity in forest ecosystems, it is important to consider not only the potential for mitigation of Al toxicity by base cations, but also the potential for factors in the soil solution to change the chemical form of Al.     

Histology of current shoots of Japanese cedar (Cryptomeria japonica D. don) inoculated withCercospora sequoiae Ellis et Everhart

The histological reaction of current shoots of the Japanese cedar,Cryptomeria japonica, inoculated withCercospora sequoiae was investigated. Wound periderm was formed on current shoots of the cedar on and after the 4th day after inoculation. In the cells of the cork layer, lignin and suberin were deposited, and a phenolic substance was accumulated. In other inoculated samples, plasmolysis, contraction of the cells and necrosis of the tissues were also observed. On the 32nd day, wound perioderm and phellogen were observed in samples of the tissue inside the necrotic tissues in response to hyphal invasion. Occurrence of wound periderm and phellogen in tissues of the needles was confirmed in the inoculated samples although no hyphae were observed in and around the tissues. These results suggest that this fungus causes necrosis of host tissues and induces defense responses. A part of this paper was presented at the 106th Annual Meeting of the Japanese Forestry Society (1995).     

Root morphology and nutritional status of Japanese red cedar saplings subjected to in situ levels of aluminum in forest soil solution

There is little information on the effects of in situ levels of aluminum (Al) in the forest soil solution on the root morphology of Japanese red cedar (Cryptomeria japonica D. Don). We evaluated whether morphological and nutritional changes in the white roots of Japanese red cedar saplings grown in glass-bead culture for 18 weeks occurred in response to Al solutions at five concentrations: 0 (control), 0.05, 0.1, 0.5, and 1.0mM. Branching white roots treated with 0.5 or 1.0mM Al had some stunted, brown, thickened tips. Their mean lengths were significantly shorter than those of roots treated with 0.05 or 0.1mM Al. The maximum diameters of white roots treated with 0.5 or 1.0mM Al were significantly larger than those of the control. Treatment with 0.5 or 1.0mM Al reduced the concentrations of Ca and Mg in the white roots and increased the concentration of Al compared with the control. These results indicate that between 0.1 and 0.5mM Al, a drastic change occurs in the effects of Al on the morphology and nutritional status of white roots of Japanese red cedar saplings, and suggest that the Al levels in Japanese forest soils may induce morphological changes in the white roots.     

In vitro screening of angiotensin I-converting enzyme inhibitors from Japanese cedar (Cryptomeria japonica)

Screening and isolation of angiotensin I-converting enzyme (ACE) inhibitors from Japanese cedar (Cryptomeria japonica) based on the in vitro ACE inhibitory assay were attempted. The ethanol extract from outer bark showed the highest inhibitory activity (IC₅₀ is 16g/ml) among 24 extracts prepared from roots, leaves, heartwood, sapwood, inner bark, and outer bark by successive extraction with four solvents. The fractionation of the outer bark ethanol extract followed by the bioassay resulted in the isolation of two strong ACE inhibitors, catechin and dimeric procyanidin B3. The bioassay of three flavan-3-ols including (+)-catechin and six flavones revealed that most of these compounds have high ACE inhibitory activity. The results suggest that the phenolic hydroxyl group at the C7 position and heterocyclic oxygen atom of these compounds are important for expressing the inhibitory activity.     

Long-term growth analyses of Japanese cedar trees in a plantation: neighborhood competition and persistence of initial growth deviations

The individual growth of tree diameter at breast height (dbh) is analyzed in an even-aged plantation of Cryptomeria japonica from stand age of 45 to 94 years, to examine how the growth of individual trees has been affected by the changes in spacing resulting from thinning operations. At any age, a significant proportion (0.37–0.46) of the variation in dbh growth during a 5–11-year period was explained by dbh at the beginning of the period, probably due to greater leaf mass of larger trees. Next, either one-sided or two-sided competition was added to the model, by calculating the basal area (BA) of neighboring trees around each tree within a given radius or BA for trees having larger dbh than the focal tree within the radius. After preliminary analyses, a radius of 8 m was selected as the critical range for tree competition. Although both types of competition explained a significant proportion (0.09–0.43) of growth variation, one-sided competition was not significant at ages greater than 54 years. Based on the model at 45 years of age, the initial deviation of growth rate for each tree from the predicted rate was calculated and added to the models as a third variable. This raised the coefficient of determination up to 0.50–0.74. These findings have practical significance for forest plantation management, particularly for controlling the growth of standing trees via thinning, to produce high-quality timber in the future.     

Contribution of active defense responses in the limitation of fungal spread in the sapwood of living sugi (Cryptomeria japonica) tree

The participation of active defense responses in the limitation of fungal spread in the sapwood of living sugi tree was determined. Isolates ofGuignardia cryptomeriae were inoculated to living trees, fresh logs, frozen and thawed logs and autoclaved logs, and the spread of wood discoloration and fungal hyphae was assessed. In autoclaved logs and freeze-treated logs, wood discoloration and reaction zone formation were not observed, and fungal hyphae of both of virulent and avirulent isolates grew rapidly in the wood. In fresh logs, wood discoloration and the formation of a pale reaction zone and transition zone were observed. Virulent isolates spread rapidly, but the spread of avirulent isolates was inhibited. In living trees, wood discoloration was observed and reaction zones were formed at lesion margins. These results indicated that constitutive defense mechanisms had no effect on the spread of both of virulent and avirulent isolates, and that active defense responses were important in the limitation of spread of fungal hyphae, hence in the limitation of wood discoloration. Further, it appeared that avirulent, but not virulent, races ofG. cryptomeriae were easily inhibited even by weak host responses. This study was presented at 105th and 106th Annual Meeting of the Japanese Forestry Society.     

Estimation of the fine root biomass in a Japanese cedar (Cryptomeria japonica) plantation using minirhizotrons

We estimated fine root biomass in a Japanese cedar (Cryptomeria japonica) plantation using a min-irhizotron technique. Since data obtained from minirhizo-trons are limited to the length and diameter of fine roots observed on minirhizotron tubes, data conversion is necessary to determine the fine root biomass per unit soil volume or unit stand area. We first examined the regression between diameter squared and weight per unit length of fine roots in soil core samples, and calculated the fine root biomass on minirhizotron tubes from their length and diameter. Then we determined conversion factors based on the ratio of the fine root biomass in soil core samples to that on minirhizotron tubes. We examined calculation methods, using a single conversion factor for total fine root biomass in the soil for depths of 0–40cm (Cal1), or using four conversion factors for fine roots in the soil at 10-cm intervals (Cal2). Cal1 overestimated fine root biomass in the lower soil or underestimated that in the upper soil, while fine root biomass calculated using Cal2 better matched that in soil core samples. These results suggest that minirhizotron data should be converted separately for different soil depths to better estimate fine root biomass.     

Effects of chronic nitrogen application on the growth and nutrient status of a Japanese cedar (Cryptomeria japonica) stand

To investigate the potential effects of nitrogen (N) deposition on Japanese forests, a chronic N-addition experiment that included three treatments (HNO₃, NH₄NO₃, and control) was carried out in a 20-year-old Japanese cedar (Cryptomeria japonica D. Don) stand in eastern Japan over 7 years. The amount of N applied was 168 kg N ha⁻¹ year⁻¹ on the HNO₃ plots and 336 kg N ha⁻¹ year⁻¹ on the NH₄NO₃ plots. Tree growth, current needle N concentration, and soil solution chemistry were measured. Nitrogen application decreased the pH and increased NO₃ ⁻, Ca²⁺, Mg²⁺, and Al concentrations in the soil solution. The needle N concentration increased in both of the N plots during the first 3 years. Nevertheless, the annual increments in height and in the diameter at breast height of the Japanese cedars were not affected by N application, and no visible signs of stress were detected in the crowns. Our results suggest that young Japanese cedar trees are not deleteriously affected by an excess N load.     

Effect of simulated acid fog on membrane-bound calcium (mCa) in fir (Abies firma) and cedar (Cryptomeria japonica) mesophyll cells

The decline of virgin fir (Abies firma) forest at Mt. Oyama has been reported. Related field observations suggest that high acidity fog is linked with its decline. However, cedar (Cryptomeria japonica) in the same area shows no symptoms of decline. For assessing effects of acid fog on membrane-bound calcium (mCa) of the leaf mesophyll cells, 9-year-old seedlings of fir (Abies firma) and 8-year-old seedlings of cedar (Cryptomeria japonica) were exposed twice a week to simulated acid fog (SAF at pH 3 with pH 5 as control) for 2 h per day in a chamber during May–December 2007 (except August). Current and 1-year-old needles were collected from seedlings and analyzed at 1-month intervals. For current-year needles of fir, mCa levels in cells exposed to SAF at pH 3 were significantly lower than in cells exposed to pH 5, especially during September 2007–March 2008. In contrast, it is noteworthy that mCa levels of cedar were maintained as virtually constant irrespective of SAF acidity, indicating that fir is more sensitive to acid fog than is cedar. Based on these results, mCa loss by acid fog might also be caused in the declining virgin fir forest at Mt. Oyama.     

Effects of the absorption of artificial acidic solutions on the root systems of Japanese red cedar (Cryptomeria japonica D. Don) cutting and saplings

The effects of the absorption of artificial acidic solutions only from below-ground parts on root systems were examined for 60 days in summer and 72 days in fall using cuttings and saplings of Japanese red cedar (Cryptomeria japonica D. Don). Cuttings and saplings absorbed the solutions through the potted soils from the reservoir of an autoirrigator and/or a simplified-autoirrigator. Nitric acid solutions of pH 2.0, 4.0 and 6.0 and distilled water (control) were used in summer, mixtures of H₂SO₄ and HNO₃ solutions of pH 2.0, 3.0 and 4.0, HNO₃ solution of pH 3.0, H₂SO₄ solution of pH 3.0 and distilled water (control) were used in fall. Although no detrimental effects of acidic solutions on saplings were observed, the rooting rate of cuttings treated at pH 2.0 in summer was significantly lower than that of the control. Root lengths and root dry weight per cutting at pH 2.0 in summer and fall were smaller than those of the control, and the difference in fall was significant. The present study revealed that the acidic treatment only from below-ground parts had detrimental effects on the root systems of cuttings, suggesting the importance of quantification of the effects on below-ground parts, as well as on above-ground parts, to evaluate the effects of acidic precipitation on trees.     

Efficiency of extracting microarthropods from the canopy litter in a Japanese cedar (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis> D. Don) plantation: a comparison between the washing and Tullgren methods

We compared the efficiency of washing versus the Tullgren method for extracting microarthropods from dead leaves and branches in the canopy of Cryptomeria japonica trees. Oribatida and Collembola were consistently the numerically dominant taxa of microarthropods, but the relative abundance differed between the two extraction methods. Oribatida accounted for more than 70% of all the microarthropods collected by the washing method but less than 30% by the Tullgren method. Collembola accounted for less than 10% collected by the washing method but about 60% by the Tullgren method. The density of Oribatida was higher when collected by the washing method than by the Tullgren method, and vice versa for the density of Collembola. Our results suggest that the washing method is appropriate for collecting Oribatida and other microarthropods, whereas the Tullgren method is better for collecting Collembola from the canopy litter of C. japonica trees.     

Host selection of small cedar longicorn beetle, <Emphasis Type="Italic">Callidiellum rufipenne</Emphasis> (Coleoptera:Cerambycidae), on Japanese cedar, <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>, in terms of bark water content of host trees

We caught the adults of a secondary wood-boring insect, Callidiellum rufipenne (Motschulsky), on Japanese cedar, Cryptomeria japonica D. Don., trees and logs with manipulated bark water contents to clarify the mechanism of host selection by C. rufipenne. More C. rufipenne were trapped when the bark water content range was ca. 120–200%. Fewer C. rufipenne were trapped at higher and lower bark water contents. These findings indicate that C. rufipenne adults do not simply select weakened or dying trees. Bark water content is one of important factors for C. rufipenne choosing their host for oviposition.     

汕头市金灶镇杨梅枯死病成因与对策

对金灶镇的杨梅枯死情况进行了调查,从栽培管理、病虫害及外部环境因素分析其成因,认为品种退化是杨梅枯死大爆发的主要原因。在此基础上,提出了品种更新、改进栽培措施等生产对策。     

The composition and abundance of microarthropod communities on arboreal litter in the canopy of Cryptomeria japonica trees

In a Cryptomeria japonica plantation, we examined the composition and seasonal abundance of microarthropods in communities associated with habitat substrates in the canopy (defined as dead leaves, dead branches, and living leaves) and compared them with those in soil communities. Habitat substrates and microarthropods were periodically collected by the branch-clipping and washing method from the canopy and by the Tullgren method from the soil. Oribatida, Collembola, and larvae of the Chironomidae, most of which are detritivorous or fungivorous, were dominant in the canopy. The dominant oribatid and collembolan families differed markedly between the canopy and the soil. Numbers of all microarthropods per unit dry weight of leaf or per unit area of branch ranged from 4.2 to 11.7g^–1 dry wt on dead leaves, 0.13–0.48cm^–2 on dead branches, and 1.3–6.4g^–1 dry wt on living leaves. In the soil, the number of individuals per unit ground area ranged from 24000 to 220000m^–2. The total abundances of microarthropods on dead leaves and dead branches were almost constant throughout the year. These results suggest that the arboreal litter characteristic of C. japonica canopies is utilized consistently by large numbers of detritivorous and fungivorous microarthropods, and that the decomposition of dead foliage and branches is initiated in the canopy.     

Induction of the biosynthesis of agatharesinol, a norlignan, in sapwood sticks of Cryptomeria japonica under humidity-regulated circumstances

To establish an experimental approach for studying the biosynthetic pathway of agatharesinol, a norlignan, induction of the formation of agatharesinol in Cryptomeria japonica (Japanese cedar, sugi) was attempted. Wood sticks were prepared from the sapwood immediately after cutting a sugi tree down, and they were allowed to stand in desiccators in which the humidity was adjusted to 76% and 88%, and in a room. When the wood sticks were allowed to stand in 76% humidity and in a room, they dried rapidly and no formation of agatharesinol was demonstrated by gas chromatography-mass spectrometry. These results suggest that in the sapwood dried rapidly, the cells that were biologically active in the sapwood, probably ray parenchyma cells, die rapidly and completely before the biosyntheses of secondary metabolites including agatharesinol was wholly established. The wood sticks allowed to stand in 88% humidity, on the other hand, dried gradually compared with the sticks placed in 76% humidity and in a room, and agatharesinol was formed as one of the predominant ethyl acetate extractives. These results suggest that delaying the drying of the sapwood sticks can control the dying period to an appropriate length for the ray parenchyma cells, during which the biosynthesis of agatharesinol is induced. Part of this study was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004     

Quantitative comparisons of antitermite extractives in heartwood from the same clones of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> planted at two different sites

The quantities of some extractives in the heartwood of 25 plus tree clones of Japanese cedar (Cryptomeria japonica) from two different sites were investigated to clarify the differences in antitermite properties in relation to clones and environmental factors. The measured compounds were cubebol, epicubebol, sandaracopimarinol, and ferruginol. The total amounts of extractives were calculated from gas chromatogram peak areas. The heartwoods from Tano (Tano Forest Research Station, Miyazaki University; 31° N, 131° E, 130 m asl) tended to contain more of the individual extractives and total extractives than those from Komenono (Komenono Forest Research Station, Ehime University; 33° N, 132° E, 700 m asl). There was a significant difference (calculated by analysis of variance) at the 1% level among clones at both sites in quantities of total and individual extractives. This result suggests that the qualities and quantities of heartwood extractives are largely affected by genetic factors. Spearman’s rank correlation with the average of the extractive quantities at the sites was investigated. The correlation coefficients of total extractives, cubebol, epicubebol, sandaracopimarinol, and ferruginol were 0.61, 0.85, 0.76, 0.67, and 0.74, respectively. This result means that the order of the amounts of these compounds among the cultivars could be maintained at different sites. It is apparent that both environmental and genetic factors affected the quantities of these extractives in the heartwoods of Japanese cedar.