Wood fiber

The objective of this study was to evaluate variations between the velocity of ultrasonic wave propagation in trees and in freshly felled logs as well as to investigate the correlation between those speeds and corrections that would improve this correlation. The study was conducted using 210 exotic trees growing in Brazil, including the species Eucalyptus grandis, Pinus elliottii, Toona ciliata, and Eucalyptus resulting from cloning. Although the velocity of ultrasonic wave propagation in a tree (V t ) is not equal to that in a freshly felled log (V l ), the two values are correlated such that V l can be obtained from V t . The regression indicated a nonlinear equation for determining the log velocity from the tree velocity.

Experiments were conducted using ASTM standard methods to determine the medium density fiberboard (MDF) expansion properties and swelling characteristics as a function of panel density and sorption state. Specimens without density profile were produced by removing the surface layers of laboratory MDF panels. The results from the trials showed that for laboratory MDF, linear expansion is homogenous in panel plane. When specimen density increased, linear expansion, linear expansion coefficient, thickness shrinkage coefficient, linear contraction, and linear contraction coefficient increased. Thickness swell was higher than thickness shrinkage at any density level. Thickness swell coefficient was higher than thickness shrinkage coefficient for low density levels. The values of linear contraction and linear contraction coefficient (in desorption) were higher than the values of linear expansion and linear expansion coefficient (in adsorption). The values on thickness swell and thickness shrinkage were much higher than the values of linear expansion and linear expansion and linear contraction at any density level. The effect of density on linear expansion, linear expansion coefficient and linear contraction coefficient was significantly stronger than the effect of density on thickness swell, thickness swell coefficient and thickness shrinkage.

The potential of proton magnetic resonance techniques, in particular magnetic resonance imaging, for analysis of western red cedar has been investigated. Proton magnetic resonance experiments were carrled out on normal sapwood, heartwood and juvenile wood and on rotten juvenile wood from westcrn red cedar logs at a range of hydration levels. Signals from the solid wood and the water were readily distinguishable, and the solid wood signal was characterized by its second moment, which was about 5 x loY sr2 above the saturation point for all samples and increased by about 20% below the liber saturation point. The water signal was separated into earlywood tracheid lumen water, latewood tracheid and ray lumen water, and bound water on the basis of spin-spin relaxation times. In the normal log, heartwood and juvenile wood had substantially less water and also shorter spin-spin relaxation times than the sapwood. The rot sample had considerably more water than normal juvenile wood. With proton NMR the sapwood/heartwood boundary of western red cedar can be distinguished easily, but the heartwood/juvenile wood boundary is more difficult to discern. Rot should be identifiable from surrounding normal wood, especially if in heartwood or juvenile wood. With current technology, magnetic resonance imaging facilities can produce cross-sectional images of whole cedar logs; however

The effect of supercritical fluid treatment on superficial gas permeability of Douglas-fir was investigated by using carbon dioxide either alone or amended with methanol. Permeability increased in a majority of samples, although nearly one-third of the specimens declined in ...

This research is intended to expand information on fiber characteristics for better understanding their complexity and potential in industrial use. Tensile properties of four types of individual cellulosic fibers, bamboo, kenaf, Chinese fir, and ramie, were measured by a custom-designed microtensile tester. Load-displacement curves for most individual fibers were found to be linear until failure. Average values of at least 30 individual fibers of bamboo, kenaf,

Ongoing research into chemically treating southern hardwoods for producing structural composite lumber suggests that some improvements may be imparted by modifying the wood. How chemical treatment(s) affect modified wood durability, particularly resistance to Reticulitermes flavipes, was the objective of this study. Water-saturated samples of yellow-poplar, sweetgum, and red oak were heated at 150 C for 30 min in two solutions: water and 1.0% NaOH; controls were also included. Samples were subjected to the AWPA E1-09 no-choice termite test in which mass loss from R. flavipes was determined. The species and treatments independently and significantly affected the mass loss. Yellow-poplar, which had the lowest specific gravity, averaged significantly greater mass loss than sweetgum and red oak for all three exposures. All species treated in water or NaOH showed a higher degree of termite degradation as compared with the controls.

A microtension testing system was devised to measure mechanical properties of individual cellulosic fibers. To avoid specimen gripping and to enhance fiber alignment during testing, a self-aligning ball and socket gripping assembly was used in the microtensile tester design. A resolution of 0.098 mN was obtained for the tensile load measurement with this microtensile tester. Fiber strain was determined from high-precision stepper motor movement with 0.078-mm resolution or by in situ video photography. Cross-sectional areas of a single fiber cell wall were measured with a confocal laser scanning microscope. Results obtained from this system indicated a linear stress-strain curve until fatal failure for mature latewood fibers, whereas juvenile latewood fibers displayed curvilinear stress-strain relationships. Average values of tensile strength, tensile modulus, and elongation at break were 1258 MPa, 19.9 GPa, and 6.6% for mature latewood fiber and 558 MPa, 8.5 GPa, and 9.9% for juvenile latewood fiber, respectively. These values agreed with published data. The preliminary test indicated the usefulness of the integrated environmental chamber for investigating moisture effect on fiber engineering properties, but further investigation is needed to obtain statistically significant data.

As previously reported, the combination of various organic biocides with relatively high levels of commercial antioxidants always increased the biocides' efficacies against wood-destroying fungi in short-term laboratory decay tests. The two principal antioxidants examined, propyl gallate (PG) and butylated hydroxytoluene (BHT), are low cost and benign. In reviewing ground-contact outdoor exposure results, samples treated with the biocide chlorothalonil and the antioxidant BHT had 2-3-fold enhanced efficacy after four years of exposure against decay and termite degradation compared to stakes treated with only the biocide. In above-ground outdoor exposure tests after three years of exposure, lap-joint samples treated with only BHT at the relatively low retention of 0.94 kgm-3 had significantly less fungal decay than untreated samples. In addition, mini lap-joint samples treated with a quaternary formulation and 2.56 kgm-3 BHT and exposed in Hilo, HI, for two years, had more than 3-fold greater decay resistance than samples without BHT. However, relatively poor results were observed for both ground-contact and above-ground samples treated with various biocides and the antioxidant PG. Less BHT may be required to protect wood outdoors than the initial laboratory decay tests indicated. The antioxidant concept appears to be an economical option for totally organic systems. A mechanism by which BHT protects wood against fungal degradation is proposed. † Member of SWST.

In Eastern Canada, black spruce (Picea mariana (Mill.) B.S.P.) has recently been introduced in the finger-jointing industry. However, little information is available on some of the key manufacturing parameters that influence the finger-jointing process. Therefore, the main objective of this work was to evaluate the effect of wood machining parameters on the ultimate tensile strength (UTS) of finger-joined black spruce in order to optimize the performance of the product. Parameters investigated in this study were the chip-load and the cutting speed. A feather profile was selected with an isocyanate-based adhesive and an end-pressure of 3.43 MPa. A factorial analysis showed a statistically significant interaction between cutting speed and chip-load on the UTS. Within the range of values studied, the cutting speed was the most significant variable affecting finger-joined black spruce. The influence of chip-load on the tensile strength of finger-joints was lower, being apparent only at lower cutting speeds. Results indicated that suitable finger-jointing could be achieved within a range of 1676 m/min and 2932 m/min of cutting speeds with a chip-load between 0.64 mm and 1.14 mm. However, within this range the best result was obtained at 2932 m/min cutting speed and 0.64 mm chip-load. Scanning microscope image analysis of the damaged cells confirmed the effect of cutting speed on the finger-jointing process. In general, the depth of damage was more severe as the cutting speed increased.

Lignin, holocellulose, cellulose, and hemicelluloses were isolated from pine wood and reacted with acetic anhydride. The order of reactivity was found to be lignin > hemicelluloses >> holocellulose. Cellulose did not react. At a level of bonded acetyl where all the hydroxyl groups were substituted on the lignin polymer, only about 20°/0 of the total theoretical hydroxyl groups on the holocellulose were substituted. The data suggest that in the reaction of chloroacetic anhydride with whole wood, the initial rate-controlling step is the rate of diffusion of reactive chemical into the cell wall.

Dimensional stability can be improved by either steaming or heating wood while the wootl is in a compressed state. This study investigated the effect of steam or heat on fixation of compression set and the effect of these treatments on hardness, mechanical properties, and color of compres ;ed and uncompressed wood specimens. To determine the effect of steaming before and after compres: ion set. one group of wood specimens was steamed and then compressed, and another group was compressed and then steamed. Simple boiling and cyclic swelling tests were used to evaluate recovery of compression set. Hardness of compressed specimens was measured by the Brinell test. A two-point bending test on noncompressed specimens was used to calculate moduli of elasticity and rupture. ii L-a-b color system was used to determine color changes. Compressed wood steamed for 1 min at 200 C or 8 min at 180 C showed no recovery of set, large increases in hardness, minimum decreases in mechanical properties, and slight darkening. We conclude that almost complete fixation of com~~ression set in wood can be achieved by steaming compressed wood.

Nanofibers were isolated from bagasse pulp pretreated with dilute hydrochloric acid, dilute sodium hydroxide, cellulase, or xylanase enzymes using high-shear ultrafine grinding and high-pressure homogenization. The effect of the different pretreatments on chemical composition and structure of isolated nanofibers was studied using chemical analyses, X-ray diffraction, and Fourier transform infrared. The dimensions and properties of the isolated nanofibers were followed at the different processing stages using optical microscopy, transmission electron microscopy, atomic force microscopy, and tensile properties (wet and dry). The diameter of the microfibrils was in the range of 7-30 nm for untreated and pretreated bagasse pulps while larger microfibrillar bands (to 150 nm wide) were observed for untreated bagasse pulp than the pretreated pulps (to 90 nm wide). Nanopaper sheets made from nanofibers isolated from alkali-and xylanase-treated pulps showed better wet and dry tensile strength than those made from the other pulps.

Birch (Betula papyrifera Marsh) condensate collected from a veneer plant in Michigan was analyzed for its major chemical constituents. This condensate contained carbohydrates and lipids. In the lipid fractions, triglycerides were the most abundant component (35-40%), followed by phenolic compounds (30%) and waxes (25-30%). Gas Chromatography-Mass Spectrometry (GC-MS) and Fast Atom Bombardment (FAB) MS were used to identify 14 lipid compounds. A white rot fungus, Phanerochaete chrysosporium [Burdsall-lombard, 5176, HHB-62511, was tested as a means for the bioremediation of the condensate. P. chrysosporium reduced the total organic content (TOC) of the condensate from 350 ppm to 22 ppm and the color intensity from 0.614 to 0.355 absorbance units, after 2 weeks incubation in a liquid medium containing yeast and pcptonc at pH 5.

Oriented strand board (OSB) manufacturers would like to reduce panel weight to save on costs and provide a lighter panel for handling during construction. This study explored the possibility of making a lighter and cheaper oriented strand board (OSB) through the addition of lignin-retained cellulose nanofibers (LCNF). The main novelty of this study was that we created a standardized “cost ratio” table, which allows for a company to take their confidential adhesive and LCNF costs and easily determine if there is a projected increase or decrease in panel material costs (%) for lighter weight panels. To summarize the methodology, engineering and multivariate statistical methods were first used to develop predictive models of panel performance in the presence of a lower density and increased LCNF, for various adhesive amounts. Next, we used these models to calculate the amount of materials needed to achieve the same strength or stiffness. We then calculated the recipe costs for each sce...

The effects ofdifferent wood drying procedures, offelling time (winter and summer), and of compass orientation within one tree (north and south side) on the fracture properties of spruce wood have been studied. A most useful parameter to characterize the fracture behavior, the specific fracture energy G. has been determined with a new splitting method. High-temperature (IOC-110 C) drying renden the lowest specific fracture energy (GJ and fracture toughness (K,,) values in comparison with 20 C fresh air, 50-60 C (kiln)-drying and prefreezing (-20 0, and air-drying. Refreezing to-20 C before airdrying provides similar values as 20 C and similar or slightly higher values as 50 C drying. Effects of felling time and of compass orientation could not be detected unambiguously.

Partially cinnamyl alcohol dehydrogenase-deficient and wild-type loblolly pine (Pinus taeda) were studied for shrinkage properties. The study established no significant difference between these two genotypes. Results also showed that shrinkage of juvenile wood is significantly different from the corresponding shrinkage of mature wood only in the radial direction. Tangential shrinkage difference between juvenile and mature wood was significant when the uncorrected values were used but not when the true shrinkage values were used, thus highlighting the need to account for the effect of growth ring curvature on tangential shrinkage measurement of small-diameter trees.

Numerical and three-dimensional finite element models were developed to improve understanding of major factors affecting hygroelastic wood properties. Effects of chemical composition, microfibril angle, crystallinity, structure of microfibrils, moisture content, and hydrophilicity of the cell wall were included in the model. Wood from wild-type and decreased-lignin transgenic aspen (Populus tremuloides Michx.) was used for experimental validation of the computer model. The model was able to predict longitudinal elastic modulus of microfibrils and woody cell walls. The difference in longitudinal elastic properties between wild-type and genetically modified aspen wood was predicted well * Corresponding author { SWST member Wood and Fiber Science, 44(1), 2012, pp. 22-35 # 2012 by the Society of Wood Science and Technology only when additional softening of hemicelluloses and amorphous cellulose of transgenic aspen was included in the model.

Numerical and three-dimensional finite element models were developed to improve understanding of major factors affecting hygroelastic wood properties. Effects of chemical composition, microfibril angle, crystallinity, structure of microfibrils, moisture content, and hydrophilicity of the cell wall were included in the model. Wood from wild-type and decreased-lignin transgenic aspen (Populus tremuloides Michx.) was used for experimental validation of the computer model. The model was able to predict longitudinal elastic modulus of microfibrils and woody cell walls. The difference in longitudinal elastic properties between wild-type and genetically modified aspen wood was predicted well * Corresponding author { SWST member Wood and Fiber Science, 44(1), 2012, pp. 22-35 # 2012 by the Society of Wood Science and Technology only when additional softening of hemicelluloses and amorphous cellulose of transgenic aspen was included in the model.

Abstract. Partially cinnamyl alcohol dehydrogenase-deficient and wild-type loblolly pine (Pinus taeda) were studied for shrinkage properties. The study established no significant difference between these two genotypes. Results also showed that shrinkage of juvenile wood is ...

Reducing lignin content is a target for processes such as papermaking because lignin removal requires a tremendous amount of energy and chemicals. Recent advances in tree genetics permit modification of lignin content and structure. The consequences of lignin modifications on many wood properties are not known. The purpose of this study was to establish the effect of genetic modification of lignin on selected wood mechanical properties. In this study, genetically modified young quaking aspen trees with reduced lignin content and/or increased syringyl to guaiacyl (S/G) ratio were investigated and compared with the wild type. The modulus of elasticity in three-point bending and the compression strength parallel to the grain were measured using modified micromechanical tests. The results indicate that the genetic modification used in this study had a negative effect on these mechanical properties. The transgenic trees with reduced lignin content showed a severe reduction in modulus of elasticity and compression strength parallel to the grain, whereas the transgenic trees with increased S/G ratio had only a slight decrease in these properties compared with the wild type. The simultaneous modification of lignin content and S/G ratio shows inconsistent results and needs further investigation.

Two nuclciir magnctic rcsonance (NMR) pulsed field gradient diSSusion approaches have been applied to the measurement of the magnitude and the distribution of the tangential dimension of cells in a number of wood samples. The results thus obtained were compared with the results from microscopy. The results from thcse two approaches agree with each other and they also givc excellent agreement with the microscopy results. The results of this work demonstrate that NMR diffusion is an accurate and convenient method for the measurement of cell sizes in wood and in similar porous systcms.

The anatomical characteristics and density of wood were examined in 23-year-old Acacia mangium trees that had been planted in Yogyakarta, Indonesia. The seeds had been collected from trees of five different provenances. The distance from the pith of the boundary between juvenile and mature wood was also examined to clarify the maturity of the wood. Lengths of wood fibers near the pith and the distance from the pith of the boundary between juvenile and mature wood differed significantly among provenances. By contrast, other anatomical characteristics of the wood such as fiber wall area, fiber wall thickness, fiber diameter, vessel lumen area, vessel diameter, vessel frequency and wood density did not differ significantly among provenances. Wood density was strongly correlated with the area of fiber walls. Our observations suggest that Sidei and Daintree might be more appropriate provenances among those examined for the Acacia mangium treebreeding programs in Indonesia that are aimed at improving wood quality, because these provenances are associated with longer initial wood fibers and narrower juvenile areas than the other provenances studied.

Recent studies demonstrated that perforated pit membranes (i.e., pit membranes with a large opening in their central portion) are commonly present between wood fibers in core eudicots. It is unclear whether this type of pit membranes might also occur in ancestral angiosperms. Therefore, structure of interfiber pit membranes was examined by field-emission scanning electron microscopy in nine species representing seven families that are located at more ancestral position than core eudicots. We found perforated pit membranes in three of the nine species. Our observations indicate that perforated pit membranes are relatively common even in ancestral groups of angiosperms. In the non-perforated pit membranes of the other six species, we found a range of structural variations. Thinwalled pit membranes without apparent intercellular layers were always found in three of the six species and the porosity of sheet-like pit membranes differed among the three species. Unlike the thin-walled pit membranes, interfiber pit membranes of Buxus microphylla var. japonica were thick-walled with obvious intercellular layers, and in Schisandra chinensis, we often observed torus-bearing pit membranes. Such variations in layered structure of pit membranes and homoplastic occurrence of torus-bearing pit membranes have not yet been reported for ancestral angiosperms. Our observations indicate that the structure of interfiber pit membranes might be more complicated than previous studies might suggest.

A Rapid Agar Plate Screening Assay (RAPSA) was developed and optimized for assaying individual extracellular enzymes produced by potential biological control agents and sapstain fungi. The RAPSA, which uses culture tiltrates rather than agar plugs inoculated with actively growing fungi as used in the classical screening method, was more sensitive in detecting activity, for all extracellular enzymes screened, with the exception of chitinase, for the majority of the fungi tested. The assay was used to screen potential biological control fungi based on comparison of extracellular enzyme profiles of ten potential antisapstain biological control fungi and three sapstain fungi, grown in liquid cultures containing either glucose, hemlock sawdust, or cell wall of the sapstain fungus Ophiostomu piceue as a carbon source. Based on extracellular enzymes profiles, biological control fungi and sapstain fungi were classified into three groups. Group I fungi produced the greatest enzyme activity when glucose was included in the medium. Group I1 fungi produced equally good activity with sawdust and glucose, while Group Ill produced high activity with both sawdust and cell wall while enzyme activity with-~ glucosc was not consistent. Five biological control candidates, Gliocladium viride 623E, G. roseum 784A, G. virens 258C, G. ro.sruni 321M, G. virens 258D. in descending order, demonstrated the full spectrum of extracellular enzyme activity screened, irrespective of the growth medium. Production of extracellular enzymes in a minimal medium augmented with sawdust or cell wall is an indicator of secondary resource capability. Gliocladiurn viride 623E and G. virens 258C demonstrated high extracellular enzyme production in both of these media. On this basis, these two fungi were judged to show the greatest potential as biological control agents. Muriannea rlegans 3868 and G. solani 8 I OA showed the least potential. 1' Member of SWST.

The lumber industry is challenged to operate more efficiently. Sawmill systems use much equipment with various technologies and their manaEement methods are very much influenced by s i x of oo-eration, employee skills, hierarchy levels, and the high volatility of softwood lumber commodity markets. Because of interactions between the different manufacturing system components, its management becomes a complex matter. It is therefore difficult to assess the effect of given perturbations or improvements on the overall system. This study proposes a modeling approach based on the concept of system that provides a comprehensive view for modeling and analyzing sawmill systems. Adaptations of existing formalisms to represent operating, information, and decision subsystems are put fonvard, while assembling these three subsystems in an overall model gives a new vision of the sawmill and a powerful tool for systems integration. This modeling approach could be used for diagnostic as well as for sawmill improvement. Various examples are provided on the application of this approach.

The applicability of a l~ewly dcviscd technique, hased on the TVilhelllry principle, for measuring wetting propcrtic; of textile fibers has hcen dclllonstrated for a series of wood l)~~l p fibers. The w e t t a l~i l i t~ of ~~nI>leached kraft, nmtral sulfite semichemical (NSSC), and tl~erii~omeclii~nic.al pulp fibcrs was detcrminetl and cliffc.rences are discl~ssed in terms of variations in chclnical compo~ition and surface n~orphology. It was found that grafting of the kraft and NSSC p~~l p s with styrene considerably decreasccl wettahility due to presencc of thc hydrophobic styrc11e polymer at the s111.face of the pulp fi11c.r.

Changes in ring density and its components with increasing distance from the pith (ie, age trends) were examined in 15-year-old trees from 60 open-pollinated families of coastal Douglas-fir [Pseudo-tsuga menziesii var. menziesii (Mirb.) Franco]. Earlywood, latewood, ...

as a basis for class discussion rather than to illustrate the effective or ineffective handling of an administrative situation. Global Case Writing Competition 2009 Corporate Sustainability Track oikos free case collection http://www.oikos-international.org/academic/case-collection/free-cases oikos free case collection Marshall et al. Columbia Forest Products 1 Upon reading the latest report from the Department of Housing and Urban Affairs, Harry Demorest found his concerns confirmed-the construction of new homes had fallen yet again across the United States. Over the past month, new home starts had declined over 14% in December; this marked the end of 2007 during which housing starts were down 25% compared to the previous year and hit a low not experienced since 1993. The question was no longer "will there be a recession?" but rather "how long will the recession last?" oikos free case collection Marshall et al.

The surfacc characteristics of trcated waste newsprint fibers were investigated using inverse gas chromatography (IGC). The surfaces of waste newsprint fibers were modified with y-aminopropyltriethoxysilanc, dichlorodiethylsilane (DCS), phthalic anhydride (PA), and maleated polypropylene. The el'fcctivene\s of these surface treatments was monitored tly the IGC adsorption curves using n-alkanes and acid-base probes. The empirical acid (K,,) and balje (K,,) characteristics (i.e., electron donor1 acceptor abilities) of untreated and trcated newsprint fibers were determined using Schultz's method and were correlated with the surface chemical compositions determined from X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The results indicated that the surface of untreated newsprint tibers had an acidic characteristic due to the electron acceptor character of the hydroxyl protons. The newsprint fibers reacted with phthalic anhydride or nialcated polypropylene also exhibited an acidic surface hchavior attributed to pen~dent carboxylic groups. Dichlorodiethylsilane produced a strong acidic surface attributed to the highly elcctronegative nature of the chlorine atoms of dichlorodiethylsilane. Howevel-, when the fibers were reacted with y-arninopropyltriethoxysilane, the basic characteristic (electron donor ability) of the fiber surfacc was increased, presumably by the prescnce of attached amino groups. k'ryrtords: Acid-base properties. cellulosic tiber, invers'z gas chromatography

A tcxtl~rr goniometrr \vus rltilized for meas~lring the azim11th:rl intensity distribution of the (040) meridional diffr;lction fro111 S O I I I~ coniferous \\loocl tissues. A compntcrizod iterative fitting method rvas r~sed to generate niathematically the experinlental diffraction cllrve and to resolve the (040) diffraction pattern fro111 the con~positc profile. The nrean 111icrofibri1 angle was then estinlated from the shape of the resolved (0 4 0) profile. The technicl~1c developed hcrein is a direct and simple ~ncthod for determining thc niean uricrofihril angle with a generally satisfactory level of precision. In addition, the technirlilc is applica1)le to ~natcrial \vith a wide range of niicrofihril angles. Atlrlitionul keyu;ortls: Pscritlotsriga w~crlziesii, Tsrrga Irctcro~~llylla, mcridional diffraction, ~nicrofibril angle, X-ray diffraction, (0 4 0) peak, numerical an;,lysis, mcrcury reflectancc ~~~e t h o d , texture gonio11icte1-. 1NTHOI)UCTION Rlicrofil~ril anglc is one of the I~asic ultrastructural characteristics of \voody ~~' 1 1 walls. It influences a nu~nber of wood properties, such as creep (El-osta and Well-\vood 1972), ~ilod~ilus of elasticity (Cowdrey and Preston 1966; Hearle 1963), and

The environmental burden of timber-based products is becoming more significant in delivering competitive advantage in term of greenhouse gas (GHG) emissions. A recent project studied the life cycle inventory of wood products from cradle to gate by FWPA and CSIRO of timber products from wood grown in Australia. It revealed that the proper allocations of CO2 sequestration by different wood based products were too cumbersome. This situation occurs due to production of many different products, by-products, and nearwaste by-products, which include biogenic products, as well as non-biogenic, different water content, units of measurement, etc. along life cycle stages. This becomes specifically difficult as most allocation have to be done on economic basis according current LCA studies that may not reflect the carbon footprint for the products. The aim of this paper is to present a simple method developed for allocating carbon impact based on carbon content of different products containing wood. The paper provides results for a comprehensive inventory of "cradle-to-gate" LCA of selected wood based products produced in Australia. The study showed that independently of others environmental burden and the allocation of CO2 sequestration can be performed without gaps and double counting.

Elasticity properties were evaluated with respect to the various commercial types of composite lumber. The study included laminated veneer lumber (LVL), parallel strand lumber (PSL), and laminated strand lumber (LSL). The experimental study was designed to better characterize the elasticity properties of these increasingly important structural composite lumber (SCL) materials. Experimental efforts for SCL material characteri~ation were performed applying the five-point bending test (FPBT) and torsional stiffness measurement test (TSMT) evaluation methodologies. FPBT provided simultaneous solution for both modulus of elasticity (E) and modulus of rigidity (G). TSMT was employed to derive both the in-plane and through-the-thickness shear moduli from a singular test scheme. Further investigation focused on axial tests under tensile and compressive loading conditions for determinations of longitudinal and transverse elastic moduli (i.e., E, and E2) combined with in-plane Poisson ratio (v,,). Presented are the descriptive statistics of the SCL elasticity data as are comparisons to the orthotropic behavior of solid wood.

The knowledge of the environmental performance of different products and services is vital in the modern world because of the climate change and other environmental problems that we are facing. Life cycle assessment is a valuable tool that allows to determine the environmental performance and compare products and services with the same function. There is no doubt that the importance of forests is crucial in the environmental protection, despite that raw wood products (roundwood, pulpwood and fuelwood) are not carbon neutral as previously thought because of the human activities during forest management processes. Apart from climate change, production of raw wood products also contribute to other environmental impact categories: acidification, eutrophication, photochemical oxidant formation and abiotic resource depletion. Previous studies have shown that the life cycle inventory (LCI) data for raw wood products should be collected from the site-specific not from more generic sources because of the significant differences in several geography and technology related factors. However, less discussed are time-related factors, which should also be acknowledged especially because of the long growing time of trees. The main objective of the present study was to determine which forest management processes should be included in the LCI for currently harvested birch (Betula spp.) roundwood in Latvia and based on these results compile the required data for the LCI. The results of forest management history analysis showed that for currently produced birch roundwood only logging operations should be included in the system boundary. Subsystems such as seed production, seedling production and silvicultural operations were not practiced or had only minor impact due to low mechanization level in the past. By taking into account the time-related factors, the LCI was developed and can be used in further calculations of environmental impacts for different wood-based products that are manufactured from currently harvested birch roundwood.

We developed a spreadsheet-based model, named ThinTool, to evaluate the cost of mechanical fuel reduction thinning including biomass removal, to predict net energy output, and to assess nutrient impacts from thinning treatments in northern California and southern Oregon. A combination of literature reviews, field-based studies, and contractor surveys was used to develop a database and equations that are required to model these three components. The volume to be removed, tree size, slope steepness, and skidding/yarding distances were identified as key variables determining fuel reduction thinning treatment cost. The user of this model can estimate fuel reduction treatment costs for a wide range of thinning prescriptions using those key variables. Alternatively, users can enter their own assumptions to customize the tool for their own operations. The net energy output function can allow users to assess potential energy contribution for biomass recovery systems by comparing the amount of energy delivered with the total energy consumed to collect, process, and transport the biomass to an energy plant. Site nutrient removals from thinning treatments were calculated based on the biomass amounts and nutrient contents for each species and the tree components (e.g., limbs, tops, and/or bolewood) to be removed. The outputs can help users to examine the environmental effects of biomass recovery and provide nutrient retention information for sustainable woody biomass production. Additional model validation from future fuel reduction thinning projects would improve user confidence in the model. ThinTool should be a useful analysis program for forest managers and planners when they are developing fuel reduction treatments that are cost-and energy-effective as well as environmentally sound.

Laboratory and field leaching exposure tests were conducted to compare the residual metal content in EN 252 (50 9 5 9 2.5 cm 3) pine sapwood stakes treated with commercial chromium-and copper-containing preservatives. Treated stakes were subjected to a series of laboratory leaching tests (CEN/TS 15119-1 and CEN/TS 15119-2) and field test exposure for 24 months. Metal content and distribution were determined prior to and after exposure. The remaining metals contents in the stakes in both laboratory tests were greater than that in field test stakes. In addition, during field test exposure metal migration occurred in the treated stakes which was not observed in the laboratory tests. Results are important in developing more realistic standard laboratory methods to evaluate the leaching behaviour of preservative components during in-service conditions.

Eucalyptus pellita F. Muell is one of pulp woods that is being developed through breeding plantation programs in Indonesia. The research aimed at exploring the chemical and morphological characteristics of fiber, and to determine the rank of plus trees from 4 provenances based on the suitability for pulps. The materials included the plus trees of E. pellita (9 years) from the 2nd generation of progeny tests in Pelaihari, South Borneo. Wood properties under investigation included the chemical properties and morphological fiber characteristics (fiber dimensions and its derived properties). In the present study, data were analyzed using descriptive statistic, Analytic Hierarchy Process (AHP) and Pearson's correlation. Results showed that the chemical properties of E. pellita, i.e. the contents of ethanol-toluene extractives, hot water soluble extractives, holocellulose, alphacelullose, and lignin were 3.

Phenotypic correlations between juvenile-maturc wood density and growth were examined based on increment corc samplcs from two plantations, a provcnancc test and a commercial plantation, of black sprucc [Picerr murianu (Mill.) B.S.P.]. The ring density componcnts arc significantly correlated to their respective ring width components: earlywood and ring dcnsities are negatively correlatcd to ring and carlywood widths, respectively, whilc ring and latewood densities arc positively correlated to latcwood width. Thesc hold truc in both juvenile and mature wood. Howevcr, the correlation between rmg width and ring density decreases with increasing age. This suggcsts that the correlation between viood density and growth rate tends to lessen as the trec ages. For each character, the correlation brtween juvcnile and mature wood is significant but moderate. Thus, juvenile wood characters arc only indicativc of maturc wood oncs. On thc other hand, trecs with 12 growth rings from the pith wcrc gootl predictors of wood density ant1 radial growth of the whole tree. Individual growth rings from the juvenile-mature wood transition zone can be used to predict to some extcnt the wood density of either rnature wood or the whole tree.

In this work, a two-dimensional mathematical model of the moisture transport and stress-strain phenomena during the conventional drying process of Eucalyptus nitens wood is presented. The model consists of a system of partial differential nonlinear second-order equations, where the moisture transport phenomenon is modeled on the concept of effective diffusion, and the stresses are modeled on the hypothesis of viscoelastic deformation, which is strongly linked to the strains by free contraction and mechano-sorption. The drying was assumed as an isothermal process and without effects of sustained loads over time (creep). Experimental tests were also carried out under constant psychometric conditions at 30/25 (°C/°C) in order to obtain transient distributions of moisture and stress. From these experimental data, the physical parameters of the proposed mathematical model were obtained by optimization in a context of inverse problem. The numerical solution of the model was obtained through the method of control volumes combined with finite elements. The results of transient distribution of moisture and stress correlate well with the experimental data.

Key message Xylem maturation depends on cambial age rather than diameter growth in Shorea macrophylla by the model selections for radial variations in cell length, wood fiber traits, and basic density. Abstract Radial variations in anatomical characteristics and wood properties were investigated in 23-year-old Shorea macrophylla (engkabang) trees planted in Sarawak, Malaysia. The effects of radial growth rates on anatomical characteristics and wood properties and the manner of xylem maturation were determined based on selected mixed-effects models. The best models of radial variation were fitted by linear functions for wood fiber length, wood fiber wall thickness, basic density, and compressive strength. Logarithmic functions were applied for vessel element length and vessel frequency, and quadratic functions were applied for vessel diameter and wood fiber diameter. Vessel diameter and wood fiber length were affected by radial growth rates although these effects on the other properties were minimal. In the fixed part of the models, the results showed small mean absolute error values of radial variation in relation to the distance from the pith according to vessel frequency and vessel diameter. In contrast, in relation to the estimated cambial age, smaller mean absolute error values were obtained for cell length, wood fiber traits, and basic density, suggesting that all properties varied from pith to bark in relation to the cambial age, except for vessel traits. Thus, in S. macrophylla, xylem maturation in cell length, wood fiber traits, and basic density were due to cambial age rather than diameter growth, but xylem maturation in vessel traits depended on diameter growth.

The pH distribution near the adhesive-wood bond line in black spruce (Picea mariana) and Douglas-fir (Pseudotsuga menziesii) bonded with various acidic and alkaline adhesives was investigated. For alkaline adhesives, exposure to moderate to high RH conditions and to ...

Acoustic emission monitoring requires applying a force to an object. In most cases, special-purpose loading devices are used for this process; however, they are subject to some operational limitations. Dynamic loading of a controlled object makes it unnecessary to use loading devices and put the object out of operation. The purpose of the study is to develop a technique of acoustic emission monitoring under dynamic loading. The paper describes results of experiments with impact loading of a glass sheet with a crack. It proposes a method for separating the total flow of acoustic emission signals into stationary groups that are typical for different acoustic emission sources.

Using a new method to determine the longitudinal shear modulus (G) and shear strength (7) of solid wood in a single test, the observed shear properties of normal (NW) and compression wood (CW) of larch samples were related to their microstructure, i.e., density, microfibril angle (MFA), and lignin content. To estimate the effective G of the solid cell wall, a semi-empirical model, which calculates G on the basis of porosity by extrapolation from experimental data, was used. For con~parison, the effective G was derived from an analytical model, which considers the cell wall as a unidirectional laminate consisting of fiber and matrix material. The analytical model proved that the effect of increased MFA and higher lignin content on G in CW balance each other to a large degree. The effective G of the cell wall calculated by the analytical unidirectional laminate model was close to the estimate of the effective cell wall G performed by extrapolation from experimental data. Both niodels and mechanical test results demonstrated that effects of variability in cell-wall ultrastructure on G are minor, compared to effects of porosity and density, respectively. A multivariate regression model combining G and density showed that a good estimate of T can be achieved using these input data. Keyu~ord.\: Cellulose, compression wood, larch (kzrix &c.idun Mill.). lignin, microfibril angle, Mode 11, normal wood, shear modulus, shear strength. 1NTRODUCTION partly due to the particular characteristics of shear failuie, which occurs abruptly. The fact that shear The dimensions of wooden load-bearing strucstrength (7) is difficult to predict from parameters tures are limited by stiffness and critical stress. In recorded in nondestructive testing also conshort. deep beams, shear strength becomes a crititributes to this cautiousness. cal factor (Keenan and Selby 1973). The design Different standardized and non-standardized stresses for shear assigned by different standards methods for the determination of the shear propare rather conservative (e.g.. DIN 4074-1 [ 19891, enies of wood and wood produca (ASTM ONORM B 4 100-2 [I 9971). This conservatism is D-143 , 1992a1, D-3044 , 1992b1, DIN 521 87- ;-Member of SWST

The objective of the present study was the determination of the extractives, acidity and ash content of three different provenances of Cupressus semprevirens wood. The specimens were collected from the sapwood, heartwood, bark and needles of the trees. The quantitative determination of the extractions was performed with two different solvents, water and ethanol. The results showed no significant differences among the three provenances (P1, P2 and P3), except for the oldest, which also had the highest extract content, a fact that is attributed to the growth of the trees without competition. Furthermore, the needles and the bark, had, in all cases, the highest ash content, while heartwood appeared to have higher contents of extractives, compared to sapwood.

Dokonano analizy definicji i niektórych podziałów klasyfikacyjnych zarówno podstawowych, jak i dotyczących budowy strukturalnej oraz technologii kompozytów i wyrobów kompozytowych. W analizie uwzględniono kompozyty o osnowie metalowej, polimerowej oraz kompozyty ceramiczne równolegle zawierające różne rodzaje składników zbrojących ze względu na skład chemiczny, postać i wymiary. Omówiono także pojęcia związane z połączeniem zbrojenia z osnową. Stwierdzono, że analizowana terminologia, pochodząca z różnych obszarów techniki i adaptowania na potrzeby kompozytów przez specjalistów z tych obszarów, jest nieuporządkowana, zawiera wiele nieprecyzyjnych pojęć i definicji, określeń wieloznacznych, a także synonimów. Podziały klasyfikacyjne dotyczące kompozytów są często niekonsekwentne przede wszystkim w doborze kryteriów stanowiących ich podstawę. Wyniki powyższej analizy wskazują jednoznacznie na potrzebę działań mających na celu uporządkowanie terminologii związanej z kompozytami. O podjęcie szerokiej dyskusji środowiskowej na ten temat autorzy zwracają się do członków i sympatyków Polskiego Towarzystwa Materiałów Kompozytowych.

Changes in growth and wood density traits were investigated across annual rings of 12-year-old trees from four selected subpopulations in lotlgepole pine (Pinus contorta Dougl. Ex Loud var. latifolia Engelm) based on X-ray densitometry profile data. Four subpopulations were constructed based on height growth and wood density as follow!;: 1) fast growth and high wood density (FH); 2) slow growth and high density (SH); 3) fast growth and low density (FL); and 4) slow growth and low density (SL). Annual ring density was initially high, declined with age until age 10, and then plateaued. Significant differences among subpopulations were found for ring density, earlywood and latewood densities, ring width, earlywood width, latev~ood proportion, and earlywood width after age 6. Wood density decreased less from the pith to the bark in both overall and earlywood densities in the FH subpopulation, resulting in denser, more hon~ogeneous wood than in other subpopulations. This suggests that it may be possible to increase wood density and homogeneity in juvenile wood of this species by selecting FH families. Overall ring density may be better improved by selecting for earlywood and latewood components separately. The earliest age of which families combining fast growth and high wood density can be accurately identified is about 7 years.

This study evaluated the relative ability of three types of wood preservatives to inhibit attack by Formosan subterranean termites (FST) (Coptotermes formosanus Shiraki) and native subterranean ter mites (Reticulitermes spp.). The study also evaluated the roles of preservative retention and penetration in preventing termite damage. Sections of boards from six wood species within the Spruce-Pine-Fir species group were pressure-treated with one of four concentrations of a borax-copper (BC) preservative composed of 93% borax (sodium tetraborate decahydrate) and 7% technical copper hydroxide or one concentration of disodium octaborate tetrahydrate (DOT) or chromated copper arsenate (CCA). Speci mens were cut after treatment, exposing untreated end-grain in specimens not completely penetrated by preservative. The specimens were exposed above-ground, protected from the weather, at a site with populations of both native and FST near Lake Charles, Louisiana. Specimens were rated for extent of termite attack after 6, 12, and 24 months of exposure. Attack by FST was more severe than that by native termites for all preservative treatments, although this difference was less obvious at higher preservative retentions. For all treatments, termites preferred to attack the center of the end-grain of the specimens where preservative was either absent or at a lower concentration. However, CCA, which had the lowest overall penetration, was more effective than either borate preservative in preventing attack, whereas some DOT-and BC-treated specimens suffered attack even with what appeared to be complete boron penetra tion. These results indicate that the efficacy of shell treatments in preventing termite attack is a function of the type of preservative. The BC wood preservative protected wood from both native and Formosan termite attack at B 2 O 3 concentrations equivalent to or lower than that of DOT treatments.

Elasticity properties were evaluated with respect to the various commercial types of composite lumber. The study included laminated veneer lumber (LVL), parallel strand lumber (PSL), and laminated strand lumber (LSL). The experimental study was designed to better characterize the elasticity properties of these increasingly important structural composite lumber (SCL) materials. Experimental efforts for SCL material characteri~ation were performed applying the five-point bending test (FPBT) and torsional stiffness measurement test (TSMT) evaluation methodologies. FPBT provided simultaneous solution for both modulus of elasticity (E) and modulus of rigidity (G). TSMT was employed to derive both the in-plane and through-the-thickness shear moduli from a singular test scheme. Further investigation focused on axial tests under tensile and compressive loading conditions for determinations of longitudinal and transverse elastic moduli (i.e., E, and E2) combined with in-plane Poisson ratio (v,,). Presented are the descriptive statistics of the SCL elasticity data as are comparisons to the orthotropic behavior of solid wood.