Wood decay fungi can efficiently decompose and metabolize recalcitrant plant cell walls, which consist of cellulose, hemicellulose and lignin. Their unique degradation processes and related enzymes have been extensively studied toward various industrial and environmental applications. The recent advances in DNA sequencing technologies and informatics have made more than 250 fungal genomes publicly available, and enabled comparative omics analyses to provide new insights regarding diversity of fungal wood degradation processes, their origins and evolutions. In this review, at first, the background of wood decay types and related enzymes was summarized, and then new insights on the molecular mechanism of the diversity of wood degradation by both white-rot and brown-rot fungi as disclosed from the current comparative genome analyses were presented. Moreover, the origin and evolutions of wood decay fungi based on molecular clock analyses were discussed.

The wood qualities of birch species grown in a plantation in Atsuma, Hokkaido, were investigated. Shirakamba (Japanese white birch; Betula platyphylla), Udaikamba (Japanese red birch; Betula maximowicziana) and Dakekamba(Erman's birch; Betula ermanii) were used. Disks were cut from the trunk at part of 2 m height above the ground and the ring widths were measured. Bending tests and compression tests were carried out. The initial radial growth of Dakekamba was smaller than that of the other species. Wood density decreased from bark to pith. The closer to the pith, the lower the bending and compression strengths were. There was little change in density or the bending and compression strengths at ground height. The plantation grown birches showed similar strength performance as naturally grown birches.

Geothermal drying treatment is one of the wood drying methods. To investigate the quantitative change of terpenes in sugi (Cryptomeria japonica) board caused by four drying treatments, extracts of sugi board dried by moderate-temperature, high-temperature, geothermal energy and air were analyzed by gas-chromatograph mass-spectrometer (GC/MS). Samples were prepared using a planer to plane dried boards (1-2 mm from the surface), and to extract the shavings with ethyl acetate. As a result, total extractive content detected by GC/MS did not differ among the drying treatments. However, content of β-Caryophllene and Thujopsene was higher in air-dried boards than in those dried by the other methods (p<0.05). Sandaracopimarinal and Ferruginol content was highest in geothermal-dried board as compared to all drying methods. From the principal component analysis, a portion of terpenes in sugi board exposed to geothermal-drying treatment was similar to that of air-dried boards.

MDF is a wood-based surface material excellent in processability, homogeneity and environmental performance, and its structural use is desired in recent years. However, basic data on the assumed performance of single shear nailed joints used in structures is insufficient. For the purpose of collecting basic data, single shear tests of nailed joints were carried out by taking species of base material (Japanese cedar, Japanese cypress, Douglas fir), MDF thickness (9, 12, 15, 18, 21, 24 mm), and nail type (N50, CN50, CN65, CN75) as parameters. The test results are as follows. The yield mode was determined by the difference of the bearing resistance between the MDF and the lumber, and the failure mode was determined by whether or not nail-head pull-through of MDF required greater force than nail withdrawal from lumber. The yield load of the nailed joint increased as the length and diameter of the nail increased, and the bearing strength of the lumber was also affected. Since the ductility was determined by the lower strength between nail-head pull-through MDF and nail withdrawal from lumber, it was the highest when the two strengths were in the same range.

Air-dried samples of 20 hardwood species were saturated with water and subjected to thermal treatment in an autoclave at 200 °C for 2 hours under a saturated vapor pressure (1.6 MPa). Gelatinous layers were observed under optical microscope for Kalopanax septemlobus and Celtis sinensis samples, which were considered to be tension wood. The other 18 samples contained no reaction wood. Structural changes of cellulose in the cell walls by the hydrothermal treatment were studied by X-ray diffraction. The diffraction peaks of 1 1 0 and 1 1 0 became closer to each other in every sample, and in many cases, merged to a single, relatively sharp peak. These phenomena suggest a change of cellulose crystalline structure from a monoclinic to a pseudo-orthorhombic system. The crystalline size calculated from the diffraction peak of 2 0 0 increased in all samples by the treatment that also induces hemicellulose leaching. Thus, the structural changes upon hydrothermal treatment are considered as a common reaction in hardwood. This phenomenon could be explained as co-crystallization of adjacent microfibrils. The d-spacing of 2 0 0 decreased by 0.8-1.6% after annealing in 17 species, while that of Kalopanax septemlobus decreased by only 0.5%, and those of Diospyros kaki and Celtis sinensis did not change by this treatment. In these 3 samples, the d-spacings of 2 0 0 were originally smaller and the crystal sizes were larger than in the other 17 samples. The proportion of peak area due to the crystalline C4 in the solid-state ¹³C CP/MAS NMR spectra suggested that the content of crystalline cellulose was higher in these 3 samples than in the other 17 samples.

As a way of examining the uneven distribution of chemicals inside fire-retardant-impregnated wood, energy dispersive X-ray fluorescent analysis (EDXRF) is thought to be effective. Slices of fire-retardant-impregnated wood (Cryptomeria japonica) were subjected to EDXRF mapping under different conditions, and the results were correlated with the weight of chemical solids in the wood. The coefficient of determination increases when the dwell time is increased, or collimator size is optimized. Regardless of the measurement conditions, the relationship was not linear but had one-to-one correspondence, so we concluded that EDXRF mapping can be an effective way of analyzing the distribution of chemicals inside fire-retardant-impregnated wood.

In order to identify the economic ripple effect on a local target area from the use of local wood, an input-output analysis of interindustry relationships was performed to calculate induced production values and induced gross added values for nine distribution scenarios. Our study was conducted by using an input-output table with Kyoto prefecture as the local target area. Final demand was assumed to be 8.132 million yen. As a result, the economic ripple effect was maximized in a scenario based on local production for local consumption (log production, lumber manufacturing and processing, and consumption all taking place within the prefecture), and induced production value under this scenario was approximately 3.5 times greater than the value in an unadjusted scenario (a scenario that represents the current lumber distribution in Kyoto Prefecture). Only four scenarios in which sites of manufacturing and processing were configured to be within the prefecture resulted in a ratio of induced production value greater than 1. While the production value was barely induced for silviculture and log production in scenarios in which log production occurs outside of the prefecture, the results show an induced production value of approximately 0.4 million yen and 1 million yen for silviculture and log production, respectively, in scenarios in which the production sites were located within the prefecture.

In processing wood bending, there is a need to clarify the increasing failure phenomena in recent years. Knowledge of physical properties for selecting wood species and a shape standard showing the relationship between thickness (s) and bending radius (r) are required. In this study, wood samples immediately after steaming were subjected to bending tests using a wooden pressing frame. In addition, three-point bending and longitudinal tensile tests were made. In the press bending tests, many cracks were found on the tensile side of the samples. Therefore, the limit of fracture strain (ε_t(Max)) was calculated from the results of the longitudinal tensile tests. It is possible while bending to shift the neutral axis from the inside of the wood to the metal side by the bending band along the wood. It is necessary to satisfy the expression (s-t) / (r + t) < ε_t(Max), where t represents the distance from the upper wood surface to the neutral plane. In addition, it was confirmed that this relationship was satisfied under the conditions where good results were obtained in the press bending tests.

The NaOH-urea pretreatment system under mild temperatures was used to modify mechanical pulp properties of wheat straw, and the effects of alkali impregnation time and treatment temperature time were evaluated through single factor tests. The results showed that the optimal conditions were chosen as NaOH and urea concentrations of 5% and 3.5%, impregnation time of 10 min, treatment temperature of 50ºC and treatment time of 60 min. Compared with the results of the NaOH-pretreated chemi- mechanical pulp production, the refining energy consumption of the mechanical pulp prepared by the NaOH-urea system was decreased by 14%, while screened yield and brightness of the pulp were increased by 1.5% and 4.2% (point) and sheet density, tensile index and burst index were increased by 3.5%, 20% and 17%, respectively.