Morphological changes of Japanese beech treated with the ionic liquid, 1-ethyl-3-methylimidazolium chloride

The morphological changes in wood tissues of Japanese beech (Fagus crenata) upon treatment with the ionic liquid, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which can dissolve cellulose, were investigated. Treatment with [C2mim][Cl] induced significant swelling of all wood tissues. However, the swelling behavior of wood fibers was different from that of vessels. Intervascular pits were occluded, and pit membranes in ray-vessel pits were broken after treatment with [C2mim][Cl]. No significant differences in swelling behavior were found between latewood and earlywood, although different morphological changes for latewood and earlywood during [C2mim][Cl] treatment were seen in our previous studies on sugi (Cryptomeria japonica). We have found that the effects of [C2mim][Cl] on Japanese beech tissues are inhomogeneous and different from those found for other wood species.     

Comparative study of morphological changes in hardwoods treated with the ionic liquid, 1-ethyl-3-methylimidazolium chloride

Three hardwoods of varying vessel arrangement were treated with the ionic liquid, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which can dissolve cellulose, to investigate its influence on wood tissue morphology. Characterization was carried out by light and scanning electron microscopy. The wood fibers of all species swelled significantly during [C2mim][Cl] treatment. The swelling behavior varied according to wood species and differed from other cell types such as ray parenchyma cells. Morphological changes of the pits also varied between wood species. Treatment with [C2mim][Cl] affects wood tissues differently depending on wood species and cell type. These differences are not due to the vessel arrangement and its presence, but possibly from the chemical component and the microfibril angle of various wood tissues.     

Reaction behavior of wood in an ionic liquid, 1-ethyl-3-methylimidazolium chloride

Reaction of Japanese beech (Fagus crenata) in an ionic liquid, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which can dissolve cellulose, was investigated. Although both lignin and polysaccharides such as cellulose and hemicelluloses can be liquefied at a treatment temperature of around 100°C, the liquefaction of polysaccharides mainly occurs at the beginning of the treatment with [C2mim][Cl]. Cellulose crystallinity in the wood was gradually broken down as the treatment continued. The solubilized polymers were depolymerized to low molecular weight compounds. The results indicate that [C2mim][Cl] is an effective solvent and reagent for the liquefaction of wood components and subsequent depolymerization of them. Part of this report was presented at the 58th Annual Meeting of the Japan Wood Research Society, Tsukuba, April 2008     

Reaction behavior of cellulose in an ionic liquid, 1-ethyl-3-methylimidazolium chloride

We investigated the reaction behavior of cellulose in an ionic liquid, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which can dissolve cellulose. The cellulose samples were treated with [C2mim][Cl] at 100, 120 and 140 °C. At the beginning of the treatment, the solubilized cellulose in [C2mim][Cl] is depolymerized into various low molecular weight compounds such as cellobiose, cellobiosan, glucose, levoglucosan and 5-hydroxymethylfurfural. As the treatment continued, some of the low molecular weight compounds reacted with the ionic liquid to form new polymers, which were black and contained nitrogen. [C2mim][Cl] is, therefore, not only a solvent for cellulose, but also a reagent for both depolymerization to produce various low molecular weight compounds, and subsequent polymerization of those compounds.     

Influence of reaction atmosphere on the liquefaction and depolymerization of wood in an ionic liquid, 1-ethyl-3-methylimidazolium chloride

The influence of reaction atmosphere on the liquefaction and depolymerization of wood in an ionic liquid, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), has been systematically studied. The wood samples were treated with [C2mim][Cl] at 120°C under various atmospheres such as oxygen, nitrogen, and carbon dioxide, both dried and humidified. The percentage of residue after the treatment shows that oxygen considerably accelerates the liquefaction of wood in [C2mim][Cl], and humidity hardly affects liquefaction under any atmosphere. Gel permeation chromatography (GPC) and high performance liquid chromatography (HPLC) analyses on the solubilized compounds in [C2mim][Cl] indicate that oxygen and humidity enhance the depolymerization of the wood component. Thus, the reaction atmosphere was revealed to influence, and 1be capable of controlling, the reaction of wood in [C2mim][Cl].     

Scots pine responses to elevated temperature and carbon dioxide concentration: growth and wood properties

Growth and wood properties of 20-year-old Scots pine (Pinus sylvestris L.) trees were studied for 6 years in 16 closed chambers providing a factorial combination of two temperature regimes (ambient and elevated) and two carbon dioxide concentrations ([CO2]) (ambient and twice ambient). The elevation of temperature corresponded to the predicted effect at the site of a doubling in atmospheric [CO2]. Annual height and radial growth and wood properties were analyzed during 1997-2002. Physical wood properties analyzed included early- and latewood widths and their proportions, intra-ring wood densities, early- and latewood density and mean fiber length. Chemical wood properties analyzed included concentrations of acetone-soluble extractives, lignin, cellulose and hemicellulose. There were no significant treatment effects on height growth during the 6-year study. Elevated [CO2] increased ring width by 66 and 47% at ambient and elevated temperatures, respectively. At ambient [CO2], elevated temperature increased ring width by 19%. Increased ring width in response to elevated [CO2] resulted from increases in both early- and latewood width; however, there was no effect of the treatments on early- and latewood proportions. Mean wood density, earlywood density and fiber length increased in response to elevated temperature. The chemical composition of wood was affected by elevated [CO2], which reduced the cellulose concentration, and by elevated temperature, which reduced the concentration of acetone-soluble extractives. Thus, over the 6-year period, radial growth was significantly increased by elevated [CO2], and some wood properties were significantly affected by elevated temperature or elevated [CO2], or both, indicating that climate change may affect the material properties of wood.     

Elevated temperature and CO(2) concentration effects on xylem anatomy of Scots pine

We studied the effects of elevated temperature and carbon dioxide concentration ([CO(2)]) alone and together on wood anatomy of 20-year-old Scots pine (Pinus sylvestris L.) trees. The study was conducted in 16 closed chambers, providing a factorial combination of two temperature regimes and two CO(2) concentrations (ambient and elevated), with four trees in each treatment. The climate scenario included a doubling of [CO(2)] and a corresponding increase of 2-6 degrees C in temperature at the site depending on the season. Anatomical characteristics analyzed were annual earlywood, latewood and ring widths, intra-ring wood densities (earlywood, latewood and mean wood density), tracheid width, length, wall thickness, lumen diameter, wall thickness:lumen diameter ratio and mass per unit length (coarseness), and numbers of rays, resin canals and tracheids per xylem cross-sectional area. Elevated [CO(2)] increased ring width in four of six treatment years; earlywood width increased in the first two years and latewood width in the third year. Tracheid walls in both the earlywood and latewood tended to become thicker over the 6-year treatment period when temperature or [CO(2)] was elevated alone, whereas in the combined treatment they tended to become thinner relative to the tracheids of trees grown under ambient conditions. Latewood tracheid lumen diameters were larger in all the treatments relative to ambient conditions over the 6-year period, whereas lumen diameters in earlywood increased only in response to elevated [CO(2)] and were 3-6% smaller in the treatments with elevated temperature than in ambient conditions. Tracheid width, length and coarseness were greater in trees grown in elevated than in ambient temperature. The number of resin canals per mm(2) decreased in the elevated [CO(2)] treatment and increased in the elevated temperature treatments relative to ambient conditions. The treatments decreased the number of rays and tracheids per mm(2) of cross-sectional area, the greatest decrease occurring in the elevated [CO(2)] treatment. It seemed that xylem anatomy was affected more by elevated temperature than by elevated [CO(2)] and that the effects of temperature were confined to the earlywood.     

Phase transformations of wood cell wall water

The amount of apparently nonfreezing water per dry mass unit significantly differs between earlywood and latewood, and drying changes the nonfreezing water content of earlywood cell walls in a time-dependent manner. However, the equilibrium moisture content of spruce wood is not affected by drying and rewetting. The results indicate that different mechanisms govern these two types of phase transformations of cell wall water. The nonfreezing water content, as determined using differential scanning calorimetry, appears to be a nonequilibrium property. It is hypothesized that the measured changes in nonfreezing water content mostly reflect changes in the porous cell wall structure, on a scale well above the molecular scale, rather than the abundance of chemical adsorption sites.     

Relationships of climate and cell features in stems and roots of black spruce and balsam fir

? The anatomical differences of mature black spruces and balsam firs were examined at stem and root level in order to characterize their wood properties at cellular level and link these differences to climate.

? Anatomical variability of these species was evaluated in relation to climate data gathered from 2001 to 2004 during the cell enlargement (CE) and wall thickening and lignification (WTL) phases. Lumen area, single cell wall thickness and total tracheid radial diameter were analyzed and regrouped into earlywood and latewood.

? Results from a principal component analysis (PCA) indicated that both first eigenvectors account for 82% and 90% of total variance for CE and WTL respectively. These component factors revealed that precipitation, humidity and number of days with precipitation significantly influence the lumen area (p = 0.0168) and radial cell diameter (p = 0.0222) in earlywood. Significant differences were registered between species and tree parts (stem and root) for the lumen area, radial cell diameter and cell wall thickness in both earlywood and latewood.

? In our study, black spruce exhibited smaller tracheid size in both stem and roots compared to balsam fir. Furthermore, the lower amount of tracheids produced during the growing season and higher proportion of latewood ensure a higher wood density of black spruce. The influence of temperature on earlywood formation is significant, whereas no influence was observed on latewood.

     

日本落叶松无性系木材性质的遗传变异

对10个10年生日本落叶松无性系的木材基本密度、管胞参数进行了测定.结果表明:木材基本密度,早、晚材管胞宽度和早材长宽比无性系间差异显著;木材基本密度,早、晚材管胞长度,早晚材管胞宽度和早晚材长宽比径向变异模式相似,即从髓心向外以曲线形式不断增加,有时亦有起伏;早材从髓心向外以近似直线的形式缓慢增加,晚材从髓心向外以曲线形式增加,初期增加幅度较大,到一定年龄后趋于水平变化并略有波动;材质性状与树木年轮间的关系以对数方程、幂函数方程、指数方程拟合效果较好;除了晚材壁腔比和早材壁厚外,其它木材性质的重复力均在0.5以上,受中度或中度以上的遗传制约,按照20%的选择率,长宽比和晚材管胞长能获得较高的遗传增益.     

Surface energy of preservative-treated southern yellow pine (Pinus spp.) by contact angle measurement

In this study, the contact angles of four different reference liquids (including distilled water, diiodomethane, formadide and glycerol) formed on the surfaces of wood, treated with chromated copper arsenate (CCA) and two other emerging copper-based water-borne systems (commercial names: NW and NS) were measured with sessile drop method. Based on the contact angle data, the surface energy was obtained from the acid-base approach. The total surface energy consisted of Lifshiz-van der Waals parameter and acid-base parameter. Results showed that the NW and CCA treatments made the wood surface more hydrophobic while the NS treatment had the reverse effect on the wood surface mainly owing to the increased penetration of earlywood. By using three liquids, diiodomethane, formamide and distilled water, the total surface energy obtained for untreated earlywood, untreated latewood, CCA-treated earlywood, CCA-treated latewood, NW-treated earlywood, NW-treated latewood, NS-treated earlywood and NS-treated latewood were 43.1, 44.5, 43.4, 45.1, 49.4, 40.6, 46.0 and 40.9 mJ/m², respectively. The surface energy of CCA-treated wood was almost the same as untreated wood. After NW and NS treatments, the surface energy of both earlywood and latewood changed a little. However, the change was not so obvious as to draw any further conclusion concerning the influence of NW and NS treatments on the surface energy of wood. __________ Translated from Journal of Beijing Forestry University, 2006, 28(4): 1–4 [译自: 北京林业大学学报]     

Reflection and transmission of visible light by sugi wood: effects of cellular structure and densification

Transmittance and reflectance of visible light by sugi wood (Cryptomeria japonica) were investigated in the longitudinal (L) and tangential (T) directions. Transmittance was the highest in the L direction and reflectance was the highest in the T direction, suggesting that structural anisotropy influences transmittance and reflectance. Intra-ring variations observed with a microspectrometer indicated that T transmittance was higher for latewood than for earlywood, but there was no such trend in for L transmittance in which the highest levels occurred near the annual ring boundaries, on either the earlywood or latewood side, and the lowest at the transition from earlywood to latewood. Dependence of L transmittance on wavelength also showed variations according to the intra-ring position. The increasing of transmittance of earlywood at wavelengths?<?500 nm with increasing wavelength was observed, but this was not confirmed for latewood because of absorption by lignin. These observations supported a previously published finding, which was based on measurements in the radial direction, that the number of internal cell wall reflections, rather than density, determines wood lightness. Indeed, in the L direction, most of the incident light passes through lumens in earlywood and through cell walls in latewood, while it is subjected to numerous internal reflections at the interface between lumens and cell walls. This was further confirmed by the transmittance of earlywood being greatly decreased by radial compression.     

Transverse swelling behavior of hinoki (Chamaecyparis obtusa) revealed by the replica method

Transverse swelling and its anisotropy in hinoki (Chamaecyparis obtusa) in several kinds of organic liquids and in water were investigated by means the replica method. There was more cross-sectional swelling of cell walls and cell wall thickness in earlywood than in latewood. Marked swelling toward cell lumens was observed in wood swollen in liquids that had higher swelling potentials than water. This suggests that the swelling of cell walls in these liquids is much greater than the external swelling. Feret's diameters of the cell lumens were reduced by swelling in all the observed cases except in the tangential direction of earlywood, suggesting that cell walls swell to a much less extent in width than in thickness. Deformation of cell shapes caused by the tensile force from the latewood were observed in the earlywood and in the transitional region from earlywood to latewood. When swollen in water, transverse swelling anisotropy caused only by the swelling in cell wall thickness were calculated to be 1.2 for the whole region over an annual ring and 1.4 for the earlywood. These values could not account for the external swelling anisotropy of 2.1. Considering obvious deformations of cell shapes in the earlywood and in the transitional region, we conclude that the interaction between earlywood and latewood is one of the prime factors contributing to the transverse swelling anisotropy of coniferous wood.Part of this report was presented at the 48th Annual Meeting of the Japan Wood Research Society, Nagoya, April 1998     

Effect of conditioning on distribution and availability of alkaline copper quat (ACQ) preservative components in earlywood and latewood of southern pine

The interactions of alkaline copper quat (ACQ) components with the earlywood and latewood tissues of southern pine were investigated. There was a highly significant redistribution of the copper amine component from the earlywood to the latewood during post-treatment fixation at 50°C, which was mainly attributed to diffusion of copper amine from the earlywood into the latewood. A small amount of copper amine redistributed between the tissues and toward the wood surfaces during drying following fixation. The redistribution within the wood was similar whether the preservative penetrated longitudinally, tangentially, or radially into the wood during pressure treatment. This redistribution resulted in lower solubility of copper, and this effect contributes to the overall copper fixation in ACQ-treated wood. The quat component did not significantly diffuse after treatment, and its concentration remained much higher in the earlywood compared to the latewood.     

Effects of chemical treatments on ultra-high-yield pulping 1. Fiber separation

Summary Specially designed wood blocks from Norway spruce were used to study the nature of the fracture surfaces developed in shear using a tensile tester. In the case of the control (water-soaked blocks), the fracture in the latewood takes place mainly in the S₁ layer while in the earlywood the fracture occurs across the double cell wall. After dilute alkali treatment, some earlywood cells also fracture in the S₁ layer. For sulfite-treated samples, on the other hand, both earlywood and latewood fracture in the middle lamella.Financial support from the Empire State Paper Research Associates (ESPRA) is greatly appreciated     

Variation Within Trees of Wood Anatomical Properties in Chinese-Fir Plantation and Their Relationship Modeling Equations

A comprehensive analysis on the variation pattern of early- and latewood tracheid morphological parameters along tree (Cunninghamia lanceolata Hook.) height, including length and width, wall thickness, tissue proportion, cell wall percentage, width of growth rings, and on the relationship among them are conducted. The results indicate an initially rapid and then gentle increase of tracheid length and width, thickness of the radial wall and tangential wall of tracheid, area percentage of tracheid from pith to outward, while S2 microfibril angle (Mfa) of tracheid, and rays percentage gradually decrease and then tend to be stable. The variation of all anatomical parameters but earlywood cell wall thickness shows no significance along tree height. The radial variation pattern of width of growth rings is characterized with initially slight decrease followed immediately by a rapid and then much more gentle increase from pith to outward. The delimitation age between juvenile and mature wood is 14-16 years. Com     

Genetic parameters for early wood and latewood densities and development with increasing age in Scots pine

? Each annual ring in pines consists of earlywood and latewood with considerable difference in density and width. To get a better determination of the genetic regulation of total wood density in Scots pine (Pinus sylvestris L.), density and width of those ring sections were measured in annual ring numbers 12 to 21 of Scots pines in a full-sib progeny test. Tree height and stem diameter were also measured.

? Heritabilities for the annual ring sections increased with age for earlywood density from 0.08 to approximately 0.25; latewood density showed similar reductions. Heritability over all 10 annual rings was 0.25 for earlywood density, 0.22 for latewood density, 0.29 for height and 0.10 for stem diameter. Genetic correlations between earlywood and latewood density and growth traits were negative, while they were strongly positive between densities of adjacent annual rings (0.70–1.0).

? Despite the higher heritability of earlywood density, the strong positive genetic correlation between those traits indicates little benefit from focusing solely on earlywood density when selecting for wood density. Analysing earlywood and latewood separately does not benefit from including the width of the corresponding ring section as a covariate. Juvenile wood may possibly turn into mature wood 15–20 y from the pith.

     

Genetic control of intra-ring wood density variation in hybrid larch (Larix gmelinii var. japonica × L. kaempferi) F1

Genetic parameters for various wood density traits were estimated in 29-year-old trees of 18 full-sib families of hybrid larch (Larix gmelinii var. japonica × Larix kaempferi) F₁. Intra-ring density variation (IDV) was also evaluated using a model that expresses the pattern curve from earlywood to latewood as a power function. A high IDV indicates an abrupt change in wood density from earlywood to latewood. The ring width and wood density traits of individual rings were determined by X-ray densitometry. Overall wood density (RD) was shown to increase with increasing ring number, ranging from 0.42–0.59 g/cm³, whereas IDV of individual rings decreased gradually from pith outwards. Estimates of individual tree narrow-sense heritability of RD and IDV were 0.66 and 0.67, respectively. IDV showed negative genetic and phenotypic correlations with RD (r _g = −0.99, r _p = −0.72). The predicted genetic gains in latewood proportion and IDV were higher than that of RD. These results suggest that the intra-ring density variation is under moderate genetic control equivalent to wood density. The trend of increasing wood density from earlywood to latewood was associated with changes in both tracheid diameter and cell wall thickness.     

The effect of axial strain on crystalline cellulose in Norway spruce

The effect of strain on dry, clear Norway spruce (Picea abies [L.] Karst.) wood was studied by tensile testing along the cell axis and by in situ X-ray diffraction measurements. The mean microfibril angle (MFA) was initially 3–12 degrees and did not decrease due to strain. Based on the positions of the reflections 200 and 004 of crystalline cellulose, cellulose chains elongated and the distance between the hydrogen bonded sheets of chains decreased due to the strain. The elongation of the unit cell parallel to the cellulose chains was twice as high in juvenile wood as in mature wood. The (X-ray) Poisson ratio ν _ca for crystalline cellulose in Norway spruce was calculated from the deformation of the unit cell. The average ν _ca of earlywood was 0.28 ± 0.10 in juvenile wood and 0.38 ± 0.23 in mature wood. In latewood, the average ν _ca was 0.48 ± 0.10 in juvenile wood and 0.82 ± 0.11 in mature wood. The average ν _ca values were not directly correlated to the crystallite dimensions or to the mean MFA in juvenile and mature earlywood and latewood. The results show that the amorphous matrix has a definite effect on the deformation of cellulose crystallites.     

Quantitative analysis of lignin using an UV microscopic image analyser. variation within one growth increment

Summary The variation of the lignin content within one growth increment of Abies sachalinensis was investigated with the aid of an ultraviolet microscopic image analyser. The lignin content was determined continuously in each cell within a growth increment. The direct photometric scanning method of UV image is believed to give accurate results for determination of the lignin content of the cell wall, since it contains fewer assumptions. The lignin content of the earlywood was higher than that of latewood in adult wood as same as the others. It was high, however, in the terminal zone of the latewood. The trends of the juvenile wood were quite different from those of the adult wood. The lignin content increased from earlywood to latewood.This paper was presented at the Wood Anatomy Congress of IAWA, Aug. 27, 1979, Amsterdam. The authors wish to express their gratitude to Prof. Dr. J. Bauch for helpful advice