Effect of coatings on ACQ preservative component distribution and solubility after natural weathering exposure

Copper and quaternary ammonium compound distributions across lumber and amounts of available or soluble components were measured in coated and uncoated alkaline copper quat-treated southern pine lumber. Lumber that was not exposed to weathering had slightly higher copper retention near the surface and a steeper quat gradient. After 3?years of natural weathering, copper and quat leachings were significantly reduced by the coatings and leaching rates were low, even though the coatings were failing. The amounts of soluble copper were significantly reduced after weathering, even after accounting for the copper leached during the exposure. The relative amount of soluble monoethanolamine (Mea) remaining after weathering was low compared with copper. This reduction in soluble amine in the wood was most likely responsible for the reduced amounts of available copper. The reduced quat leaching from coated samples is attributed to the extended effectiveness of the coatings in the earlywood.     

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.     

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]     

The effects of within-species and between-species variation in wood density on the photodegradation depth profiles of sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa)

Low density wood is more rapidly eroded than denser wood when exposed to the weather, possibly because it is more susceptible to photodegradation. Fourier transform infrared microscopy was used to examine: (1) the depth of photodegradation in earlywood and latewood of sugi (Japanese cedar) and earlywood of hinoki (Japanese cypress) exposed for up to 1500 h to artificial sunlight emitted by a xenon lamp (375 W/m² within the 300 to 700 nm spectral range); and (2) the relationship between the density of wood tissues and depth of photodegradation. The depth of photodegradation varied between species (sugi and hinoki) as well as within a growth ring (sugi earlywood and latewood), and there was an inversely proportional relationship between depth of photodegradation and wood density. These findings may explain why low density earlywood is more rapidly eroded than latewood during weathering, and more generally, why there is an inverse relationship between the density of wood species and their rate of erosion during artificial and natural weathering. Part of this work was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004     

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.

     

Morphological changes in sugi (Cryptomeria japonica) wood after treatment with the ionic liquid, 1-ethyl-3-methylimidazolium chloride

We investigated morphological changes in wood tissues of sugi (Cryptomeria japonica) resulting from treatment with the ionic liquid 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which dissolves cellulose. Treatment with [C2mim][Cl] caused dissociation and distortion of tracheids in latewood, but not in earlywood. This difference was due to the difference in swelling behavior of the cell wall between earlywood and latewood. Many pit membranes in bordered pits were broken by treatment with [C2mim][Cl]. In addition, some chemical changes in wood components, such as cellulose and lignin, occurred before significant disruption or destruction of the cell wall. Our results show that the reaction of wood liquefaction by [C2mim][Cl] treatment is not homogeneous, both from chemical and morphological viewpoints.     

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.     

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.

     

Statics and kinetics of water vapor sorption of small loblolly pine samples

A better understanding of the sorption behavior of different wood structures could be useful in protecting wood against wood deterioration and fungal attack. The purpose of this study was to investigate the effect of differences among earlywood, latewood, and tree ring location within the stem cross-section of loblolly pine (Pinus taeda) on the sorption kinetics and statics of water vapor under ambient conditions. The water vapor sorption of earlywood and latewood in different tree rings was recorded using a dynamic contact angle analyzer under relative humidity changes from 11 to 89%, as provided by saturated salt solutions. Earlywood had higher sorption rates and diffusion coefficients than latewood, while outer tree rings had higher sorption rates and diffusion coefficients than inner tree rings. The sorption isotherms of earlywood, latewood, and different tree ring locations within the stem cross-section were fitted very well by a Hailwood–Horrobin model.     

Control of tracheid cross-sectional dimensions in Norway spruce and Scots pine wood raw material

Abstract

Wood properties, including tracheid cross-sectional dimensions, show a large degree of variation. To improve the properties of products made from wood, different methods to control variation have been developed. This study aims to determine the theoretical efficiency of three control strategies: the fractionation of pulped tracheids into earlywood and latewood, the separation of juvenile and mature wood, and sorting of logs according to tree size. The efficiency of each method was studied by first constructing virtual trees from measured tracheid cross-sectional dimensions, then simulating the efficiency of above-mentioned methods. The tracheid dimension data include Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.). The simulations show that separation into earlywood and latewood classes has the highest theoretical efficiency and yields the lowest variances in raw material. Classification into juvenile and mature wood groups is the second most efficient method, and the sorting of logs according to the size class of the tree is the least efficient method. It was also concluded that the variation in cell-wall thickness and radial diameter mainly originates from differences between earlywood and latewood, whereas the variation in tangential diameter mainly originates from differences between mature and juvenile wood.     

Fibril angle of loblolly pine wood as related to specific gravity,growth rate,and distance from pith

Summary Fibril angles were greater for earlywood (avg. 33.4°) than for latewood tracheids (avg. 26.9°). For earlywood, fibril angle did not differ between growth rates when the specific gravity was low (avg. 33.3°). When the specific gravity was high, wood of fast growth had a higher fibril angle (avg. 35.1°) than wood of slow growth (avg. 32.0°). No differences were detected between core, middle, and outer wood. In latewood tracheids, fibril angles were greater in corewood (avg. 28.0°) than in middle or outer wood (avg. 26.3°). For whole wood (a weighted average of earlywood and latewood), fibril angle averaged 30.7° and was greater in corewood (avg. 32.2°) than in middle or outer wood (avg. 29.9°).     

Influence of growth rate on specific gravity and other selected properties of loblolly pine

Summary Forty lobiolly pine trees were studied for the purpose of finding a possible reason for the growth rate-specific gravity controversy. In addition, properties such as specific gravity of earlywood and latewood, latewood percentage, and their relations with growth rate and specific gravity of wood were investigated.The results show that, in general, significant relationship do exist between specific gravity and number of rings per inch for growth rates ranging from approximately 3...8 rings per inch. Specific gravity was generally unrelated with slower growth rates, i.e., more than 8 rings per inch.Specific gravity of specimens having the same number of rings per inch varied according to height-decreasing with increasing height. Latewood percentage was related to number of rings per inch in a similar manner as specific gravity. Within a tree, latewood percentage of wood having the same number of rings per inch decreased with increasing height.Negative relationships between earlywood specific gravity and number of rings per inch were found to be significant for the 30 percent height and for all heights when combined. However, there was no significant relationship between latewood specific gravity and number of rings per inch. Average laterwood specific gravity decreased with height. Earlywood specific gravity only decreased from 5.3...30 percent height levels and then showed an increase. In general, wood properties such as specific gravity and latewood percentage of wood, specific gravity of earlywood and latewood, varied more from breast height to approximately the 30 percent height, than between equal distances above the 30 percent height level.     

木材（特征图象）的微机识别

通过对“微机辅助木材识别系统WIP-89”项目的发展和增补,在木材识别方式上有新的突破,即通过木才解剖图象,微机自动识别木材,现已解决针对树材中的早材至晚材,急变和渐变;阔叶树材中的环孔材、半环孔材和散孔材。     

Fibre morphological effects on mechano-sorptive creep

The increased creep rate of paper under load during moisture cycling conditions as compared to that at high constant humidity is a problem in the use of packaging materials. In order to investigate the influence of morphological factors of the fibres on the occurrence and magnitude of this phenomenon, i.e. the occurrence of mechano-sorptive creep, studies on wood fibres isolated from different parts of spruce wood were performed. Thus, creep properties were studied on earlywood and latewood fibres from both juvenile wood and mature wood. In general, latewood fibres showed a higher degree of mechano-sorptive creep than earlywood fibres, and mature wood showed a higher degree of mechano-sorptive creep than juvenile fibres. The difference in mechano-sorptive creep rate between different fibres was shown to be correlated to the differences in fibril angle. The smaller the fibril angle the higher was the mechano-sorptive creep ratio. It was suggested that at fibril angles approaching 45° wood fibres do not exhibit mechano-sorptive creep.     

Modelling elastic and shrinkage properties of wood based on cell structure

Summary In a previous article of the authors a model was developed for estimating elastic and shrinkage properties of a softwood cell-wall. In the present article this model is enlarged to simulate the elastic properties of defect-free softwoods. The wood model consists of earlywood, latewood and ray cells, each of which have a different cell-wall structure. In the model the ratio of earlywood to latewood is defined by a given wood density. The calculated elastic properties are in good agreement with test results.     

Chemical composition of earlywood and latewood in Norway spruce heartwood,sapwood and transition zone wood

This study focused on the distribution of wood components along a cross section of a spruce stem. Thin samples of earlywood and latewood were analysed by special micro-scale analytical techniques. Heartwood contained significantly more lignin and less cellulose than sapwood. The total content of hemicelluloses was the same along the radial direction, but the distribution of sugar units differed. The amounts of arabinoglucuronoxylan and pectins were larger in the heartwood. The transition zone between heartwood and sapwood had a specific composition, with less lignin and lipophilic extractives than heartwood and sapwood. For earlywood and latewood, significant differences were found in the distribution of sugar units in hemicelluloses. Latewood contained clearly more galactoglucomannan than earlywood, and conversely less pectins. The lipophilic extractives were also less concentrated in the latewood.Abbreviations EW or E earlywood - LW or L latewood - HW heartwood - SW sapwood - TZ transition zone wood - A.R. annual ring - AcBr Acetyl bromide - Ara arabinose - Xyl xylose - Gal galactose - Glc glucose - Man mannose - Rha rhamnose - GlcA glucuronic acid - MGlcA 4-O-methyl-glucuronic acid - GalA galacturonic acid - o.d. oven dry     

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.     

Profile of bordered pit aspiration in Cryptomeria japonica using confocal laser scanning microscopy: pit aspiration and heartwood color

Nine trees of Cryptomeria japonica from six elite tree clones with a broad range of heartwood colors were selected. The profiles of pit aspiration percentage (ASP) of earlywood and latewood from pith to bark for green and air-dry conditions were determined to study the relationship between heartwood color and pit aspiration. Confocal laser scanning microscopy (CLSM) observations showed that the ASP of earlywood was low in sapwood and high in heartwood in the green condition. Pit aspiration increased in intermediate wood when compared with sapwood. On the other hand, latewood pits did not aspirate during heartwood formation. Comparing the air-dry condition with the green condition, sapwood pits aspirated during drying in both earlywood and latewood; however, there was no significant difference in pit aspiration of heartwood. There was no significant difference between samples with red and black heartwoods for ASP. The difference in ASP between individual trees was larger than that by heartwood color. The general advantage of CLSM over light microscopy is that serial optical sections along the Z axis can be obtained for any moisture condition, without the need for thin sectioning or embedding.     

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     

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