Neuropharmacological activities of phytoncide released from <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>

Forest-air bathing and walking (shinrin-yoku) is beneficial to human heath. In this study the phytoncide (volatile compounds) released from Cryptomeria japonica plantation forest was characterized by using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). The main volatile compounds were α-pinene (19.35%), β-myrcene (16.98%), d-limonene (15.21%), and γ-muurolene (7.42%). Furthermore, the neuropharmacological activity of the essential oils from leaves of C. japonica (ECJ) was evaluated by several animal behavior tests. ECJ could prolong the sleeping phase of ICR (imprinting control region) mice in the pentobarbital-induced sleeping time model. Furthermore, both EJC and one of its monoterpenes, d-limonene, possessed potent anxiolytic and analgesic activities based on the results obtained from elevated plus maze and writhing tests. The volatile compounds released from C. japonica provide relaxing and stress-relieving effects on mice, and further study on the effect of phytoncide on humans is worthwhile.     

Longitudinal shrinkage variations within trees of sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) cultivars

The longitudinal shrinkage variations within trees and the relationship with density, microfibril angle, and modulus of elasticity were examined for five sugi cultivars selected for different within-tree distributions of density, microfibril angle, and modulus of elasticity. The cultivars showed significant differences in longitudinal shrinkage and in its within-tree distribution. The within-tree distributions were categorized into two types: (1) large values of longitudinal shrinkage near the pith that decreased with height and from pith to bark, (2) small values of longitudinal shrinkage near the pith that increased slightly from pith to bark. There were strong relationships between longitudinal shrinkage and microfibril angle, and modulus of elasticity, with large values of longitudinal shrinkage associated with large microfibril angle and low modulus of elasticity. Sugi exhibited large variation in longitudinal shrinkage within stem and among cultivars, with the variation strongly affected by microfibril angle. Part of this article was presented at the 56th Annual Meeting of the Japan Wood Research Society, Akita, Japan, August 2006     

Tangential and radial shrinkage variation within trees in sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) cultivars

The transverse shrinkage variation within trees was examined for five sugi cultivars. The within-tree trends of tangential shrinkage (α _T) were different by cultivar, whereas radial shrinkage (α _R) increased from pith to bark in most cultivars. The tangential/radial shrinkage ratio (α _T/α _R) decreased from pith to bark in most cultivars, because the radial variation of α _R was larger than that of α _T. The cultivars showed significant differences among cultivars in α _T, α _R, and α _T/α _R, but the difference among cultivars for α _T/α _R was smaller. The relationships between transverse shrinkage and microfi bril angle (MFA), basic density (BD), tree ring parameters, and modulus of elasticity were examined. The α _T and α _R showed positive relationships with BD, latewood percentage, latewood density, and modulus of elasticity, and negative relationships with MFA and ring width. The relationships with earlywood density were weak. Sugi exhibited variation in transverse shrinkage within stem and among cultivars, with the variation affected by MFA, density, and tree ring parameters. Part of this article was presented at the 56th Annual Meeting of the Japan Wood Research Society, Akita, Japan, August 2006, and the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, Japan, August 2007     

A trial to detect optimal pin-pricking timing in evaluating the ability to form traumatic resin canals of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> for selecting resistant trees to <Emphasis Type="Italic">Semanotus japonicus</Emphasis> (Coleoptera: Cerambycidae)

A trial to detect optimal pin-pricking timing in evaluating the ability to form traumatic resin canals (TRCs) of Cryptomeria japonica was examined to select resistant trees to Semanotus japonicus using 14 clones in 2001 and 2002. Resistance to S. japonicus and the ability to form TRCs in the phloem was evaluated by inoculating newly hatched larvae in the bark and by a pin prick, which was conducted every 10 days (four times) on the trunk around the larval phloem-feeding period, respectively. The larval survivorship varied greatly among clones for both years. The mean appearance of newly formed TRCs was generally higher in late treatment for both years, and the tangential width of them was also higher in 2001, whereas those of pre-formed TRCs were not higher for either year. The larval survivorship did not show significant correlations with the appearance and the width of pre-formed TRCs on all treatments. However, it showed significant negative correlations with the appearance of newly formed TRCs on the second and third treatments on the 2-year-old layer, although this was not significant with the width of them. This suggests that resistant clones might have the mechanism of rapidly forming TRCs when just at the stage of newly hatched larval entering the phloem. Thus, although the relationship between the appearance and the width of newly formed TRCs is not clear, pin-pricking treatment when the newly hatched larvae just enter the bark may be one of optimal times for the evaluation of the resistance of C. japonica to S. japonicus. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Estimation of stand volumes using the <Emphasis Type="Italic">k</Emphasis>-nearest neighbors method in Kyushu,Japan

The k-nearest neighbors (kNN) method is widely employed in national forest inventory applications using remote sensing data. The objective of this study was to evaluate the kNN method for stand volume estimation by combining LANDSAT/ETM+ data with 622 field sample plots from the Japanese National Forest Inventory (NFI) in Kyushu, Japan. The root mean square error (RMSE) and relative RMSE of the volume estimates rapidly decreased as the number of nearest neighbors (k) increased up to five, and then it slightly declined. They were consistently smaller for the Euclidean distance than for the Mahalanobis distance. The estimation errors (RMSE and relative RMSE) were 169.2 m³/ha and 66.2%, respectively (k = 10). The relative RMSE was similar to the previous studies. The estimated values were more accurate towards the mean value of the total volume, with an overestimation of the low volumes and an underestimation of the high volumes. We found a significant linear relationship between the observed stand volumes and estimated errors, which suggests that systematic errors may be reduced using this linearity. This research concluded that the kNN method is suitable for estimating stand volumes in Kyushu.     

Resistance of gamma-irradiated sapwood of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> to biological attacks

Any means helpful for the promotion of termite feeding activity has potential for use in a matrix in termite bait application. Therefore, energy transfer by gamma irradiation is worthy of consideration for converting wood into termite-accessible material. Wood specimens gamma-irradiated at 100 kGy and at lower levels were tested for their degrees of polymerization (DP) of cellulose and biological resistance. The DP of cellulose adversely decreased with increased doses of gamma irradiation. Termite wood consumption rates, which were determined by laboratory tests using undifferentiated larvae (workers) of Coptotermes formosanus Shiraki, were significantly higher at 100 kGy than at other doses. On the other hand, the decay resistance of gamma-irradiated wood against the fungi Fomitopsis palustris (Berkeley et Curtis) Murrill and Trametes versicolor (L. ex Fr.) Quel did not vary by irradiation dose.     

The composition of volatiles from tatami mats containing hinoki (<Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis>) wood-wool and its decline over the long term

Volatiles inside tatami mats containing hinoki (Chamaecyparis obtusa) wood-wool as padding were analyzed. Volatiles were collected with solid-phase microextraction (SPME) fibers in a small chamber prepared in tatami mats and assayed by gas chromatography. Most of the detected compounds are typically found in hinoki extractives. Monoterpenes rapidly decreased at the beginning of the experiment, while the dispersion of sesquiterpenes that contain hydroxyl groups was observed to last more than 1 year. These sesquiterpenes, T-cadinols, and α-cadinols may play a role in the suppression of house dust mites. Part of this report was presented at the 55th Annual Meeting of the Japan Wood Research Society in Kyoto, March 2005     

Structural unit of xylans from sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) and hinoki (<Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis>)

Arabinoglucuronoxylans (AGXs) isolated from the holocellulose of sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa) contained one 4-O-methyl-d-glucopyranosyluronic acid (4-O-Me-d-GlcAp) residue per 6.2 d-xylopyranose (d-Xylp) residues and one 4-O-Me-d-GlcAp residue per 3.8 d-Xylp residues. These AGXs were subjected to partial acid hydrolysis. Analyses by size exclusion chromatography and electrospray-ionization mass spectroscopy of the neutral sugar fractions in the hydrolysates showed the presence of xylooligosaccharides having a degree of polymerization of 2-8 in addition to d-Xyl, suggesting that the AGXs from sugi and hinoki contained unsubstituted chains consisting of at least eight d-Xyl residues. The acidic sugars in the hydrolysates were separated into two series of aldouronic acids composed of 4-O-Me-d-GlcAp and d-Xylp by ion-exchange chromatography. The first series included aldouronic acids from aldobiouronic acid (4-O-Me-d-GlcAp-Xyl) to aldopentaouronic acids (4-O-Me-d-GlcAp-Xyl₄). The second series were aldouronic acids composed of two 4-O-Me-d-GlcAp residues and 2-4 d-Xyl residues. In these acidic sugars, the uronic acid side chains were located on two contiguous d-Xyl residues. These facts indicated that AGXs from sugi and hinoki had a structural unit containing two 4-O-Me-d-GlcAp residues on two contiguous d-Xyl residues as well as AGXs from spruce and larch.     

Aboveground biomass equations for individual trees of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>, <Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis> and <Emphasis Type="Italic">Larix kaempferi</Emphasis> in Japan

Generic equations are proposed for stem, branch and foliage biomass of individual trees in even-aged pure stands of Cryptomeria japonica, Chamaecyparis obtusa and Larix kaempferi. Biomass data was collected from a total of 1,016 individual trees from 247 stands throughout Japan, and five regression models were assessed by root mean square error, mean bias, fit index (FI), and AIC. The results show that a power equation using diameter at breast height (dbh) and height is the most suitable for all species and components. This equation is more accurate than the familiar power equation that uses ‘dbh² height’, and it expresses the greater volume of branch and foliage mass of trees with a lower height/diameter ratio. A power equation using dbh is more reasonable for models with dbh as the only independent variable and more accurate than a power equation using ‘dbh² height’ for estimating branch and foliage mass. Estimating error for branch and foliage mass is larger than that for stem mass, but the entire aboveground biomass can be estimated with an error of less than 19%, except in the case of small trees with dbh less than 10 cm.     

Chemical changes in terpenes of sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) wood during steam drying in kiln at high temperature

Sawdusts of sugi (Cryptomeria japonica) wood prepared before and after steam drying at 120°C in a kiln were extracted with n-hexane and ethyl acetate to give n-hexane extracts and ethyl acetate extracts. From gas chromatography-mass spectrometry analysis of the ethyl acetate extracts from woods before and after steam drying, the components of 4-epi-cubebol, cubebol, and 2,7(14),10-bis-abolatrien-1-ol-4-one, which existed in the raw sugi wood, were proved to disappear in the steam-dried wood. These components were also absent in the ethyl acetate extract of the steam-condensed solution of waste steam from the kiln outlet. When these three components were treated with 0.2% (v/v) acetic acid solution at 120°C, δ-cadinene was produced as a major product from both 4-epi-cubebol and cubebol by dehydration and cleavage of the cyclopropane ring, and cryptomerone from 2,7(14),10-bisabolatrien-1-ol-4-one by hydration. The chemical changes of the three components presumably occur during steam drying of the sugi wood. This study was presented in part at the 85th Spring Meeting of the Chemical Society of Japan, Kanagawa, Japan, March 26–29, 2005     

Early establishment of broadleaved trees after logging of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> and <Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis> plantations with different understory treatments

We studied the effects of the amount of advanced regeneration before logging and different understory treatments on forest recovery, particularly the establishment of lucidophyllous (evergreen broadleaved) species, following the logging of conifer plantation with a focus on the sprouting ability. The establishment of lucidophyllous tree and shrub species originating from advanced regeneration was closely related to the total amount of these elements in the advanced regeneration, regardless of understory treatment. The understory-left treatment could preserve understory as surviving individuals by high proportion (60% or more of the understory) compared with the understory-cleared practice after logging. However, half of the surviving individuals were damaged to some extent by logging and skidding. Relatively large trees were likely to survive with no damage, indicating that they face a lower risk than smaller trees. In understory-cleared stands, a high proportion (60% or more) of the understory regenerated by resprouting. However, the resprouting ratio depended on tree size and species. Therefore, as well as the amount of the understory, the tree size of understory before logging would be also an important factor for early forest recovery. Further, the infrequent (low-density) species could easily disappear after logging because of their low resprouting ratio and low density. Thus, recovery from resprouting alone would risk simplification of the species composition after logging. We concluded that leaving the developed understory intact before logging can enhance the speed and biodiversity of forest recovery.     

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.     

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.     

Results of preliminary selection for the second generation plus trees by private foresters in three genetic tests with controlled pollinated progenies of sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) in Kyushu

Second-generation plus tree selections were assessed in three genetic tests of sugi (Cryptomeria japonica) in Kyushu: at Kumamoto, Saga, and Miyazaki. The selections were made by private foresters choosing good trees according to their own preferences when the tests were around 30 years of age. A retrospective selection index applied to the results of selection revealed that the foresters had put more emphasis on stem straightness than on growth. This trend was particularly evident at Kumamoto, whereas the foresters at Miyazaki and Saga had allocated nearly the same weight to growth as to stem straightness. Broad-sense heritabilities on dbh, stem straightness and bottom stem crookedness were 0.226, 0.256, and 0.206, respectively. These estimates were regarded as almost the same as narrow-sense heritabilities, because non-additive genetic variances were found to be small. Relative gains, assuming that the selections are propagated with rooted cuttings, were predicted to be around 10% for stem straightness, 7% for bottom-stem crookedness, while the gains on dbh were variable among the tests: ranging from 3% at Kumamoto up to around 8% at Saga and Miyazaki.     

Effects of flooding depth on growth,morphology and photosynthesis in <Emphasis Type="Italic">Alnus japonica</Emphasis> species

The present study deals with effects of flooding depth on growth, morphology and photosynthesis in Alnus japonica species thorough one field study and two controlled experiments. In the field study performed in Kushiro Mire, Hokkaido Island, Japan, tree heights and stem diameters decreased with an increase in water depth accompanied with the reduction of soil redox potential. In contrast, the rate of multiple stems per individual tree increased. In the controlled experiments for seedlings flooding suppressed the shoot elongation and biomass increment in roots. However, diameter increment around water levels, epicormic shoot development and adventitious root formation were enhanced in flooded seedlings. The photosynthetic rate and stomatal conductance of flooded seedlings also were lowered with an increase in flooding depth. The recovery of the reduced photosynthetic rate and stomatal conductance occurred simultaneously with the advancement of adventitious root formation in the flooded seedlings. These results indicate the importance of a series of morphological changes occurring on stems around water levels in flood tolerance in A. japonica species.     

<Emphasis Type="Italic">Bursaphelenchus mucronatus</Emphasis> (Nematoda: Aphelenchoididae) vectored by <Emphasis Type="Italic">Monochamus </Emphasis><Emphasis Type="Italic">urussovi</Emphasis> (Coleoptera: Cerambycidae) in Hokkaido,Japan

Bursaphelenchus mucronatus Mamiya et Enda has been recovered for the first time from adults of the cerambycid beetle, Monochamus urussovi (Fischer), in Hokkaido, Japan. The nematode was also recovered from the inner bark of Picea jezoensis (Siebold et Zuccarini) Carrière and Abies sachalinensis (Fr Schmidt) Masters infested with M. urussovi larvae. PCR–RFLP analysis indicated that B. mucronatus in Hokkaido is the European type.     

Bioremediation of CCA-treated wood by brown-rot fungi <Emphasis Type="Italic">Fomitopsis palustris</Emphasis>, <Emphasis Type="Italic">Coniophora puteana</Emphasis>, and <Emphasis Type="Italic">Laetiporus sulphureus</Emphasis>

This study evaluated oxalic acid accumulation and bioremediation of chromated copper arsenate (CCA)-treated wood by three brown-rot fungi Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus. The fungi were first cultivated in a fermentation broth to accumulate oxalic acid. Bioremediation of CCA-treated wood was then carried out by leaching of heavy metals with oxalic acid over a 10-day fermentation period. Higher amounts of oxalic acid were produced by F. palustris and L. sulphureus compared with C. puteana. After 10-day fermentation, oxalic acid accumulation reached 4.2 g/l and 3.2 g/l for these fungi, respectively. Fomitopsis palustris and L. sulphureus exposed to CCA-treated sawdust for 10 days showed a decrease in arsenic of 100% and 85%, respectively; however, C. puteana remediation removed only 18% arsenic from CCA-treated sawdust. Likewise, chromium removal in F. palustris and L. sulphureus remediation processes was higher than those for C. puteana. This was attributed to low oxalic acid accumulation. These results suggest that F. palustris and L. sulphureus remediation processes can remove inorganic metal compounds via oxalic acid production by increasing the acidity of the substrate and increasing the solubility of the metals.An erratum to this article can be found at     

Changes in water distribution in heartwood along stem axes in <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>

 Three-dimensional distribution of water in the heartwood of Cryptomeria japonica D. Don was observed by soft X-ray photography. The within-tree variation in the distribution of “wet areas” (water-accumulated areas in heartwood) was enormous, as was the variation among trees. Although we found no universal pattern of changes in wet area distributions along the stem axes of all trees, similarities among individual trees within each cultivar and clone were observed. The difference between the two kinds of wetwood in C. japonica – genetically defined wetwood and secondarily induced wetwood – is discussed, as is the use of soft X-ray photography in Japanese tree breeding programs. Received: December 21, 2001 / Accepted: May 1, 2002 Part of this paper was presented at the 46th Annual Meeting of the Japan Wood Research Society, Kumamoto, Japan, April 1996 Correspondence to:R. Nakada     

Successful <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of <Emphasis Type="Italic">Populus tomentosa</Emphasis> with apple <Emphasis Type="Italic">SPDS</Emphasis> gene

The problem of salinized soils has become one of the most serious constraints to agricultural and forest productivity. With the purpose of enhancing salt stress tolerance of Populus tomentosa, we transformed this tree species with spermidine synthase （SPDS） genes derived from an apple by an Agrobacterium-mediated method. Four transgenic clones were confu＇med by PCR and Southern blot analysis. As well, the expression of introduced SPDS genes was analyzed by real-time quantitative PCR.     

<Emphasis Type="Italic">Ophiostoma</Emphasis> species associated with bark beetles infesting three <Emphasis Type="Italic">Abies</Emphasis> species in Nikko,Japan

Ophiostoma species were isolated from bark beetles and Abies mariesii, A. veitchii and A. homolepis attacked by the beetles in Nikko, Tochigi, central Honshu, Japan. One to two Ophiostoma species were frequently isolated from each species of bark beetle. Ophiostoma subalpinum was the most common associate of Cryphalus montanus. Ophiostoma sp. B as well as O. subalpinum was a common fungus associated with Polygraphus proximus. Ophiostoma europhioides was isolated from Dryocoetes hectographus and D. autographus as one of the common associates. Ophiostoma sp. J and Ophiostoma sp. S were frequently isolated from D. autographus and D. striatus, respectively. These fungi seem to have specific relationships with particular bark beetles. Ophiostoma sp. B, Ophiostoma sp. J and Ophiostoma sp. S have unique morphological characteristics and appear to be new species. Five trees of A. veitchii, approximately 43 years old, were inoculated with five Ophiostoma species to assess the relative virulence of the fungi. Ophiostoma subalpinum, Ophiostoma sp. B, and O. europhioides had relatively higher virulence than the other species studied.