Sorption of Cr(VI) on the wood of Japanese larch treated with concentrated sulfuric acid

A carbonaceous sorbent was prepared from the wood of Japanese larch (Larix leptolepis) by dehydration with concentrated sulfuric acid in a 69% yield. The abilities of the sorbent to remove Cr(VI) from aqueous solutions were investigated. Research parameters included the initial solution pH, temperature, and initial concentration of Cr(VI) in solution. The removal of Cr(VI) was highly solution pH dependent and was mainly governed by physicochemical sorption under weak acidic conditions. The equilibrium data fit well in the Langmuir isotherm model. The Langmuir constants were calculated at different temperatures, and the sorption capacity increased with rising temperature, indicating the endothermic nature of the Cr(VI) sorption onto the sorbent. The desorption experiments suggest that the Cr(VI) sorption is generally irreversible, owing to strong interaction of HCrO ₄ ⁻ with the active sites of the sorbent.     

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     

Genetic improvement in pine wilt disease resistance inPinus thunbergii: The effectiveness of pre-screening with an artificial inoculation at the nursery

Open pollinated progenies from 15 clones of Japanese black pine (Pinus thunbergii), that had been selected for their tolerance to pine wilt disease, were tested by artificial inoculation with pine wood nematode for six years at a nursery of Kyushu Regional Breeding Office. Family variations in the respective year were all significant. An analysis of variance across the six years’ tests confirmed highly significant effect of year and of families; however, the year by family interaction was significant also. Phenotypic and genetic variances estimated from each year’s result were fitted to a quadratic regression using their mean survival ratio as an independent variable. The variances were greatest at around 0.5 of the mean survival ratio. Estimated heritability showed a similar trend of change, whereas the peak of the expected amount of improvement shifted toward the lower survival range: around 0.4, where a greater selection differential was anticipated. It was concluded that a useful amount of genetic improvement that may be reduced by 30% due to the interaction, would be expected by prescreening seedlings where the mean survival ratio after inoculation was around 0.25 to 0.6.     

日本落叶松在旺苍县引种栽培初步研究

通过对旺苍县盐井河采育场10多年来引种栽培日本落叶松的结果与旺苍县外其它地区的引种栽培试验结果和本地华山松的生长情况进行对比分析，证明引种是成功的，进一步探讨了日本落叶松在旺苍的引种效果和生态适应性，提出了旺苍自然地理分布的引种适生区，是旺苍北部中山区主要速生造林树种之一。     

Optimum planting density for Japanese oak (Quercus mongolica var.grosseserrata) based on spacing experiment with systematic design

A spacing experiment for Japanese oak (Quercus mongolica var.grosseserrata) with Nelder's design have been studied at the Kyushu University Forest in Hokkaido, since 1975. The oak seedlings were planted according to systematic spacings which were 20 levels varying gradually from 40,816 to 1,086 seedlings per hectare with concentric circular arcs (22 in number) and spokes (41 in number). In 1992 when the planted oak seedlings were 18-year-old, DBH, crown diameter, total height and clear length of the survival trees were measured. Based on the results obtained from analyzing the relationships between planting density and the mean values of each block, the optimum planting density should be 7,241 seedlings per hectare. The title is tentative translation from the original Japanese title by the authors of this paper.     

Genotypic effects on the variation of wood quality and growth traits in plantation forest made by cutting cultivars of Japanese cedar

We studied the effect of genotypes of planting stocks regarding the variation of the modulus of elasticity of tree trunks on standing trees (trunk-MOE), tree height (TH), and diameter at breast height (DBH) in a 19-year-old Japanese cedar plantation made with root cuttings. Trunk-MOE was assessed nondestructively using a tree-bending method. Genotypes of individual trees were detected using the random amplified polymorphic DNA (RAPD) technique. RAPD analysis revealed that the sampled plantation consisted of 14 genotypes. Genotypic effects on DBH and TH were unclear, and there was no significant difference among genotypes. This result indicated that an acquired variation should have more influence than an inherited variation on DBH and TH. For trunk-MOE, there were significant differences among the four largest genotypes at the 5% level. However the coefficient of variation in trunk-MOE of each genotype ranged from 7.5% to 26.8%. It seems reasonable to assume that the wide variation in trunk-MOE in a sampled plantation may depend on the environmental effect within a clone as well as on the genetic origin of clones. We therefore conclude that the use of multiple planting stocks from different cuttings for which the wood quality is unknown contributed strongly to the wide variation in trunk-MOE in the plantation of Japanese cedar.     

Composition of pyrolyzate from Japanese green tea

Green tea is a beverage that is produced by hot-water extraction of the leaves of tea (Camellia sinensis L.). As the amount of green tea consumption has increased, the importance of using the residue has grown. To address this problem, chemical compositions of two pyrolyzates obtained with an electric kiln, L and G, which were obtained from the tea leaf product and its hot-water extraction residue, respectively, were examined. Both pyrolyzates were alkaline, in contrast to the acidic pHs that are typical of pyrolyzates from wood materials. The major constituents were nitrogen-containing compounds, which accounted for up to about 70% (based on gas chromatography-mass spectrometry peak area). Caffeine was the main compound in both samples, although it might not be a pyrolysis product but actually sublimates from the samples and then condenses back into the pyrolyzates. Other nitrogen-containing compounds were formed mainly from proteins and amino acids. Acids and phenols, which are typical components in pyrolyzates obtained from wood materials and contribute to acidic pH, were rare in both samples. Other neutral compounds are known as compounds in pyrolyzates from wood materials. The pyrolyzates obtained in this experiment were novel and may have new uses.Contents of this report was presented in the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, 2002     

Decomposition behavior of woody biomass in water-added supercritical methanol

The chemical conversion of Japanese beech (Fagus crenata Blume) in water-added supercritical methanol was studied for a wide range of water content using a batch-type reaction vessel to obtain chemicals from lignocellulosics. It was consequently found that addition of water enhanced the decomposition of wood cell wall components; cellulose, hemicelluloses, and lignin. In cases of high water content, however, it resulted in low solubility of lignin-derived products causing an increase in the mass of the residue. The water content was thus optimized to be around 10% (v/v) for the decomposition of wood. Concomitantly, the yields and selectivity of the chemicals from wood could be regulated by the addition of water, especially for the lignin-derived products. As a result, the monomeric compounds of lignin, coniferyl alcohol and sinapyl alcohol, were recovered as their γ-methyl ethers in the presence of water in higher yields than those obtained without addition of water.     

日本科柿果实发育期间单宁和糖类的变化

甜柿是柿(Diospyros kaki Linn.f.)树的自然类型,属日本主要栽培果树之一,其特点是果实采后不需人工脱涩即可食用,甜脆爽口,风味独特。近年来,日本甜柿已在我国大量引种栽培,国内对甜柿的生物学习性和栽培方法已作了不少观察和研究。但对甜柿果实的生长发育过程及果实发育期间生化物质消长规律的研究尚未见报道。作为柿果主要成份     

Blackening of Diospyros genus xylem in connection with boron content

The amount of boron contained in the xylem of Japanese persimmon (Diospyros kaki Thunb.) and ebony (Diospyros ebenum Koen) was determined by inductively coupled plasma (ICP) emission spectrometry and a modified curcumin–acetic acid method. The boron content was compared between the heartwood and sapwood of ebony as well as between a blackened portion (“kurogaki”) and normal portion of Japanese persimmon. The kurogaki contained a higher level of boron than the normal portion of the same individual, although the boron content varied among individuals. Moreover, the boron content of the heartwood of ebony was much higher than that of the sapwood. These results suggest the participation of boron in the blackening of Japanese persimmon. Because both kurogaki and heartwood of ebony are durable to fungal attack, the blackening of Diospyros genus appears to be related to the formation of defensive substances in which boron seems to take part. The convenient curcumin–acetic acid method is an alternative to the ICP method with comparable accuracy.