Cesium adsorption from aqueous solutions onto Japanese oak charcoal III: effects of water-extraction treatment

To remove group 1 and 2 metal ions from Japanese oak (Quercus serrata Thunb. and/or Quercus crispula Blume) charcoal (OC), a water-extraction treatment was employed. The treatment was repeated 1, 4, 8, or 12 times. The amounts of four metal (sodium, potassium, magnesium, and calcium) ions eluted from non-treated and treated OC were determined using an ion chromatographic apparatus. The effects of water-extraction treatment on the ability of OC to adsorb cesium were investigated using 2.50 × 10^?5 and 2.50 × 10^?6 mol/L aqueous cesium chloride solutions. As for both aqueous solutions, an unexpected result was obtained in that the cesium-adsorption ability of OC decreased suddenly when the repetition of water-extraction treatments exceeded a certain threshold. We explain the results in terms of pH of the sample solutions and the point of zero charge for OC.     

Removal of cadmium (II) from aqueous solutions by adsorption using meranti wood

Meranti wood, an inexpensive material, has been utilized as an adsorbent for the removal of cadmium (II) from aqueous solutions. Various physico-chemical parameters such as equilibrium contact time, solution pH, initial metal ion concentration, and adsorbent dosage level were studied. Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherms were used to analyze the equilibrium data at different temperatures. The experimental data fitted well with the Langmuir adsorption isotherm, indicating the monolayer adsorption of the cadmium (II). The monolayer adsorption capacity of meranti wood for cadmium (II) was found to be 175.43, 163.93 and 153.84?mg/g at 30, 40, and 50°C, respectively. The thermodynamics of cadmium (II) adsorption on meranti wood indicates its spontaneous and exothermic nature. Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model. The results indicated that the meranti wood could be an alternative for more costly adsorbents used for cadmium (II) removal.     

Development of an acid soil conditioning agent from lignin by ozone treatment III: improvement of ability of lignin to form an aluminum complex and to reduce aluminum toxicity after ozone treatment

Lignin prepared by a modified Klason method (KSL) was modified with ozone followed by alkaline treatments. The original and modified KSLs were subjected to a plant growth test with radish (Raphanus sativus L. var. radicula Pers.) in the presence of AlCl₃ (37.5 μM) to assess their ability to reduce aluminum toxicity. The formation of an aluminum complex with these KSLs was also examined by potentiometry. Neither the original nor alkaline-treated KSLs had an effect on aluminum toxicity or the formation of a complex, except for the alkaline-treated KSL at a maximal dose of 250 mg/l, which reduced aluminum toxicity. However, all the KSLs modified with ozone and alkali were effective at forming a complex and reducing aluminum toxicity. The dose of saponified ozone-treated KSLs required to reduce aluminum toxicity became lower and their water solubility increased as the ozone treatment was prolonged. These findings clearly show that water solubility and the ability to form a complex with and reduce the toxicity of aluminum were improved by ozone treatment of KSL.     

Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin III: effects of sodium chlorite treatment

To obtain high-strength phenol–formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, we investigated the effects of sodium chlorite (NaClO₂) treatment on wood prior to low molecular weight PF resin impregnation. Sawn veneers of Japanese cedar (Cryptomeria japonica) were treated with 2% aqueous NaClO₂ solution at 45°C for 12 h to remove lignin, and the process was repeated up to four times, resulting in weight loss of 21%. NaClO₂ treatment has shown considerable potential for high compression of PF resin-impregnated wood at low pressing pressure, especially after adding moisture to a content of 10%–11%. This deformation is further enhanced during pressure holding by creep deformation. The density, Young’s modulus, and bending strength of PF resin-impregnated veneer laminated composites that were treated with NaClO₂ four times and compressed at 1 MPa, reached 1.15 g/cm³, 27 GPa, and 280 MPa, respectively. The values in untreated PF resin-impregnated wood reached 0.8 g/cm³, 16 GPa, and 165 MPa, respectively.     

The Japanese pulp and paper industry: an analysis of financial performance from 1991 to 2001

This article discusses the determinants of profitability expressed as return on capital among Japanese pulp and paper companies. Return on capital is measured as income before tax related to stockholders’ equity. Return on capital has been divided into profit margin and asset utilization rate. The hypothesis is that return on capital can be explained by mill size, productivity, product line, financial situation, and use of wood resources. The dataset consists of 13 larger Japanese pulp and paper companies listed in Pulp &; Paper Statistics. Data on financial performance, production, and use of wood fibers were collected for the period 1991–2001. The average return on equity for the studied companies is 4.2%. Labor productivity has increased quite significantly, from about 600 to 1,000 kg/employee and year. An econometric analysis indicates that the best model fit is found when the asset utilization rate is used as the dependent variable. Significant variables are, among others, asset utilization rate lagged one time period (?), labor productivity (+), capital productivity (?), paper production as a share of total paper and board production (?), total value of assets on the books (?) and solidity (+). This may indicate that the total value of assets on the books is large in relation to the total production of paper, paperboard and pulp.     

Discoloration induced by Raffaelea quercivora isolates in Quercus serrata logs and its relation to phylogeny: a comparison among isolates with and without the Japanese oak wilt incidence including outside of Japan

Japanese oak wilt (JOW) has been prevalent in Japan since the late 1980s. Infections of the fungus, Raffaelea quercivora Kubono et Shin. Ito, which is transmitted by an ambrosia beetle [Platypus quercivorus (Murayama)], can cause JOW. Although R. quercivora, P. quercivorus, and oak trees are distributed in other Asia–Pacific countries, the incidence of JOW has not been reported outside Japan. In this study, we collected R. quercivora isolates from 5 Asian countries, including Japan, and compared their ability to induce sapwood discoloration by inoculating Q. serrata logs. The tangential widths of the discoloration in sapwoods inoculated with non-Japanese isolates were equivalent to or greater than those of the 2 Japanese isolates. This indicates that a lack of JOW incidence outside Japan is not because of the lowered ability of R. quercivora to spread discoloration compared with the Japanese isolates. Statistical analyses of the relationship between discoloration and phylogeny based on DNA sequences of actin and chitin synthase showed that the discoloration width was independent of phylogenetic relatedness among the isolates. To discuss why the occurrence of JOW has not been reported outside Japan, further studies (e.g., on host susceptibility and P. quercivorus aggression) throughout Asia are needed.     

Erratum to: Mechanical properties of wood in an unstable state due to temperature changes,and analysis of the relevant mechanism III: Effect of quenching on stress relaxation of chemically modified woods

In order to understand the mechanism of destabilization occurring when wood is quenched, we applied chemical modifications, and controlled the number of moisture adsorption sites in wood. The degree of destabilization was evaluated according to the fluidity (1-E _t/E ₀), increase in fluidity, and relative fluidity in relation to the nonmodified wood, and was discussed by comparing these quantities with the hygroscopicity or swelling of wood. We found that destabilization of chemically modified wood was lower than that in nonmodified wood, and the amount of adsorbed water controlled the magnitude of flow of wood. Moreover, according to the analysis of water state by the Hailwood-Horrobin equation, it was shown that the function of dissolved water to the fluidity is almost identical for both chemical modifications, whereas hydrated water has more effect on acetylated wood than on formaldehydetreated wood. We speculate that the motion of water molecules due to quenching accompanied with the redistribution of energy resulting from the exchange of their potential energy and movement to attain a new balance, and the introduced acetyl groups and cross-linking restrict the water molecule movement. An erratum to this article is available at .     

Litter carbon inputs to the mineral soil of Japanese Brown forest soils: comparing estimates from the RothC model with estimates from MODIS

The level of organic carbon found in soil is the result of the balance between litter input to the soil and decomposition. Litter input to the soil is closely related to net primary production (NPP); at equilibrium, the NPP is equal to the litter input to soil. Plant litter input to a depth of 30 cm in the mineral soil was estimated for Japanese forest using the Rothamsted Carbon model (RothC) and an average value of soil organic carbon (SOC) content, and was compared with estimated litter inputs from the NPP dataset from Moderate Resolution Imaging Spectroradiometer (MODIS). A Monte Carlo uncertainty analysis of the input SOC was also conducted in order to reveal the sensitivity and uncertainty of the model to input SOC. The litter carbon input calculated using RothC and that derived from MODIS NPP were positively correlated, but the mean estimated litter input from RothC was 17.2% smaller than that estimated from MODIS. Mapping the normalized difference revealed spatial biases in the difference. The discrepancy was probably because of the different temperature controls for the MODIS algorithm and the RothC model, and also our simple assumption in the RothC calculation. This comparison reveals a close link between litter inputs estimated from SOC data and litter inputs estimated from satellite-based NPP data. The discrepancies between the estimates merit further study.     

Maturation and plant recovery from embryogenic cells of Japanese larch: Effect of abscisic acid in relation to their morphology

Two embryogenic cell lines characterized by different morphology and color, white and red, were obtained from an immature zygotic embryo of Japanese larch (Larix leptolepis Gord.). Mature somatic embryos with cotyledons and regenerated plants were obtained from both cell lines. However optimal concentration of abscisic acid (ABA) for maturation varied depending on morphology of ECs. From the white ECs which intermingled with somatic embryos of very early stage, mature somatic embryos were induced on maturation medium containing 50 μM of ABA. On the other hand, mature somatic embryos with cotyledons were observed from the red ECs which consisted of somatic embryos of more developed stage on hormone-free medium or 0.1 μM ABA containing-medium.     

Investigation on hydrogen abstraction from methyl glucoside by active oxygen species under oxygen delignification conditions III: effects of the origin of active oxygen species

Carbohydrate model compounds methyl β-d-glucopyranoside (MGPβ), methyl α-d-glucopyranoside (MGPα), and methyl β-d-mannopyranoside (MMPβ) and the deuterium compounds of MGPβ labeled at the anomeric or C-2 positions (MGPβ-1D, MGPβ-2D) were reacted with active oxygen species (AOS) generated in situ by reactions between O₂ and a co-treated phenolic lignin model compound, 4-hydroxy-3-methoxybenzyl alcohol (VAlc), under conditions simulating oxygen delignification (0.5 mol/l NaOH, 0.36 mmol/l Fe³⁺, 1.1 MPa O₂, 95°C). MGPβ was degraded more than MGPα but less than MMPβ when the pairs MGPβ/MGPα and MGPβ/MMPβ, respectively, were treated, which indicates that the configurational differences at the anomeric and C-2 positions influence the reactivity of AOS toward these compounds. When the pairs MGPβ/MGPβ-1D and MGPβ/MGPβ-2D were treated, no clear kinetic isotope effects were observed in either case. These results contrasted with those obtained when another phenolic compound, 2,4,6-trimethylphenol (TMPh), was used as the AOS generator instead of VAlc under exactly the same conditions. Clear kinetic isotope effects were observed when using TMPh. Because it is not easily accepted that the anomeric and C-2 hydrogen abstractions are minor reaction modes only for AOS generated in the VAlc system, it is suspected that the AOS do not show any clear kinetic isotope effect even though the AOS abstract an objective hydrogen.     

Fire effects on germination of seeds from Rhus and Rubus: competitors to pine during natural regeneration

Throughout the southeastern United States, Rhus and Rubus species are common associates of the southern pines on a wide array of upland site and stand conditions. Because of their ability to overrun disturbed sites, these species are categorized as competitors to pine during stand regeneration. Since prescribed burning is often used for site preparation in advance of pine regeneration, this study investigated the effect of fire on the germination of seeds from three pine competitors (Rubus argutus Link, Rhus copallina L. and Rhus glabra L.). During dormant-season burns, sumac seeds were located 45 cm above litter, within the F layer of a reconstructed forest floor, and at the interface of the forest floor and mineral soil. During growing-season burns, fresh blackberry fruits were placed at heights of 0, 15, 30, and 45 cm above the surface litter of a reconstructed forest floor. In subsequent germination tests, sumac seeds from within the F layer of burned litter had significantly higher germination rates for smooth sumac (31%) and shining sumac (42%) as compared to unburned control seeds (1–5%). In general, germination rates for sumac seeds placed in the air or on mineral soil during burning were no better than control seeds. Seeds from blackberry fruits that were located at heights of 15, 30, and 45 cm had germination rates that were comparable to unburned control seeds (18%), but seeds from fruits placed on the litter during burning had <1% germination. Results suggest that sumac seed germination may be enhanced by the heat from prescribed burning, whereas blackberry seeds showed more germination response to multiple germination cycles which indicated a potential for long-term storage in the soil seed bank.     

Quantitative estimation of carbon removal effects due to wood utilization up to 2050 in Japan: effects from carbon storage and substitution of fossil fuels by harvested wood products

Carbon absorbed by forests remains stored in the timber used for wood products, and a change in wood product stock can be evaluated as substantial removal/emission of atmospheric carbon. Since the carbon storage effect due to harvested wood products (HWP) might be taken into account in the future framework of carbon mitigation, it is crucial to estimate the carbon fl ow and stock concerning HWP for the next commitment period. In the present study, we developed a model for estimating the fl ow and stock of wood products in Japan’s building, furniture, and paper sectors. The HWP carbon storage effect and substitution effect (carbon reduction by substituting fossil fuels and energy-intensive materials with HWP) up to 2050 were quantitatively estimated by lifetime analysis. Our model simulation revealed that (i) the carbon stock change in Japan due to HWP would be evaluated as a large emission if the atmospheric-fl ow approach is adopted, (ii) carbon removal would not significantly increase if the ratio of newly constructed wooden buildings/furniture remains stable, and (iii) the carbon storage effect together with the substitution effect would have a significant impact on climate change mitigation if the ratio of newly constructed wooden buildings/furniture is gradually improved to 70% by 2050.