Japanese cedar wood was acetylated, impregnated with polystyrene (PS) and then compressed in the radial direction. The dynamic Young's modulus (E'), bending strength and dimensional stability of that wood-PS composite were measured to investigate the effects of inter-cellular adhesion with the introduced PS resin. The acetylation and the following PS impregnation had little influence on the E' of the wood, but after hot-pressing at 180°C, the wood was effectively densified and its E' in the tangential direction was significantly enhanced. Such an enhancement was not recognized when the PS-impregnated wood was compressed at room temperature. The improved mechanical properties due to the hot-pressing was explained by the adhesion of the wood cell walls with the PS resin. That inter-cellular adhesion was also effective to fix the compressive deformation of wood: the reversible and irreversible swelling due to alternate dry-wet cycles were considerably reduced when the acetylated wood-PS composite was hot-pressed.

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Studies were carried out to obtain the relation between carbohydrate content and fruit body yield of Auricularia polytricha on a sawdust-based medium. Mannitol and mannose resulted as favorable carbon sources for mycelial growth. Carbohydrate metabolites content was one of the important factors for fruit body formation, and resulted in maximum yield on 50 days culture. Glycogen content was clearly revealed to be inversely related to fruit body formation ratio. Trehalose content did not influence fruit body yield. Mannitol was a favorable metabolite for fruit body formation, but arabinitol showed no relationship in a polyol metabolism.

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Wood identification was performed on the decorative and structural elements of the tea room at Konchi-In temple in Kyoto, Japan, prior to the recent restoration. Examination was done in collaboration with Kyoto Prefecture and the results were reflected in actual repair or selection of substitute materials. Minimum amount of samples that are necessary for identification were collected carefully from deteriorated parts, from cracks, and from the deteriorated area so as not to alter the surface appearance. Hand-sectioned samples were observed under an optical microscope and the sample was identified on the basis of microscopic anatomical features. These investigations allowed us to learn of Enshu's wood selection and usage in the tea room “Hasso-seki”. For example, that a variety of Pinus Subg. Diploxylon sp., Castanea crenata, and Prunus sp. were used for the pillars “Tokohashira” seems quite interesting for the Japanese style of architecture, and furthermore it envisages a cultural interaction between the architectural styles of the Korean peninsulas. Wood identification is necessary not only to investigate the original wood species but also as part of other research such as the value of the building, the transition of wood selection and the regional characteristics of building materials. In the future, we have to increase the identification of wood in heritages such as tea rooms, shrines, and temples, in order to build the database of wood usage. In summary, wood identification based on anatomical features is a facile but accurate technique, and provides a useful guide for restoration. Such collaboration between conservators, curators and wood specialists is becoming more and more important.

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Japanese cedar wood was acetylated and glued with polyvinyl acetate (PVAc), polyethylene (PE) and polystyrene (PS). The bond properties of those thermoplastics were examined in air-dry and wet conditions. The bond strength of PVAc was slightly reduced by the acetylation of wood when the PVAc was applied in water emulsion form, but the reversed trend was recognized when the PVAc was diluted with ethyl acetate. This fact indicates improved wettability of acetylated wood for hydrophobic diluents. The wood acetylation significantly improved the bond strength of PS, while it affected that of PE only a little. This fact suggests that the acetylation is effective to enhance the affinity of wood for PS rather than PE. The acetylated wood-PS system showed excellent water resistance: its bond strength was reduced by only 10-20% after immersion in warm water, while the PVAc and PE showed 30-90% reduction in bond strength.

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Anti-termite performance of fifteen species of Japanese and foreign timbers was evaluated using two subterranean termites, Reticulitermes speratus (Kolbe) and Coptotermes formosanus Shiraki in laboratory tests. In addition, field trials in nine sites were conducted under protected above-ground conditions to know the effects of peripheral environment and termite species on the performance of tested timbers. In the results of laboratory tests with un-weathered samples, lower anti-termite indices of 80%, which was set as a threshold of anti-termite performance, were observed in Sequoia sempervirens, Eucalyptus diversicolor, and Cryptomeria japonica for C.formosanus, and in S.sempervirens, E.diversicolor, and C.japonica for R.speratus. After weathering, anti-termite indices were decreased remarkably in Thujopsis dolabrata, S.sempervirens and C.japonica for R.speratus, whereas, they were almost the same as those of the un-weathered samples for C.formosanus. The field trials resulted in greater damage by E.diversicolor among high-density hardwood species. Damage ratings of tested species strongly varied with different test sites.

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A new method of dying wood in parallel colored strips through the process of capillary penetration (simultaneous parallel capillary penetration dying) was developed to create beautiful rainbow-patterned wood products for use as educational and/or DIY craft materials. This method allows for the simultaneous absorption of multiple dying solutions after sample pieces of Pinus radiata sapwood, the most permeable wood, are processed using an electric hand trimmer to cut 3 straight, gear-like grooves 5mm wide and 13mm deep into the base of the wood. Pieces of Pinus radiata sapwood, processed as above and treated with silicon so that dying solutions would be absorbed along the cross section, the tangential section and the cut surface of the gear-like grooves, respectively, were made to absorb 4 dying solutions each. Relationships between the amount of dying solution applied, the dying process, and the resultant coloring patterns were then analyzed and compared. Results obtained were as follows; 1) In the area above the arched cut surface, penetration of the combined solution of Violet 7 (V7) and Violet 10 (V10) water-soluble dyes at 0.3% (w/w) and a 33% diluted emulsion of Yellow pigment in a 5:3:10 ratio occurred gradually in a tangential direction after having risen longitudinally from the surface in direct contact with the solution. In longitudinal penetration, the yellow pigment rose most quickly, followed by V10, then finally V7. This pattern was repeated in tangential expansion, except that V7 did not spread in this direction. This penetration of the dye/pigment solutions creates interesting gradations of color between adjacent columns. 2) In the case where absorption was made to initiate along the cut surface, the V7 dye in the combined liquid has a tendency to spike sharply, thus creating peaked patterns of gradated color.

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Differences between sugi (Cryptomeria japonica D.Don) wood and enzymatically saccharified wood residues (ESR) in chemical constituents and adsorption/desorption isotherms of water vapor at 25°C were measured. Hot press moldings and wood-plastic composites by injection molding were then prepared from these to study moisture characteristics, dimensional stability and mechanical properties of the yielded moldings. Equilibrium moisture content of ESR extracted with hot-water was higher than that of sugi wood (control) at more than 60% RH, even though the holocellulose content of the former decreased to one-half that of the latter. The hot press moldings with a density of 1.2g/cm³ prepared from the ESR showed less hygroscopicity and swelling compared to those made from sugi wood. Swelling due to water soaking of the wood-plastic composites was only one-half when using the hot-water extracted ESR. These results are to be expected for the utilization as an additive for inhibiting swelling of ESR.

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