Utilization of wood biomass residues from fruit tree branches,evergreen hardwood shrubs,and Greek fir wood as raw materials for particleboard production. Part B. Hygroscopic properties and formaldehyde content

This paper investigates the basic hygroscopic properties and formaldehyde content (FC) of particleboards produced with wood biomass from fruit tree branches and evergreen hardwood shrubs as substitute raw materials for fir particles. One-layer laboratory particleboards with two distinct target densities (0.63 g/cm³ and 0.69 g/cm³) were produced using various mixtures of the above materials. Industrially produced wood particles were also used for comparison purposes. The results showed that the replacement of fir wood (FW) by evergreen hardwood material significantly upgraded board's quality in terms of thickness swelling (TS) and water absorption (WA) (except boards with density of 0.63 g/cm³) after immersion in water for 24 h and residual swelling (RS) after reconditioning. The contribution of branch-wood (BW) particles in the production of FW boards with density of 0.63 g/cm³ induced increase of TS, WA, and RS while for boards with density of 0.69 g/cm³ did not result to significant changes except for RS. In terms of FC, boards made of BW and evergreen hardwood showed significantly lower FC compared to those produced by FW and industrial particles.     

Reinforcement of fiberboard containing lingo-cellulose nanofiber made from wood fibers

Wood-based materials are fabricated with adhesives composed of various materials derived from fossil fuels. It is difficult to identify replacements for these chemical adhesives. This study explored nanofiber technologies as an alternative to these adhesives. In this study, we focused on reinforcement effects of lingo-cellulose nanofiber (LCNF) on fiberboards made from softwood and hardwood fiber. We discuss the density effects of reinforcement with LCNF because the density of medium-density fiberboard (MDF), which is widely used for construction, is standardized at about 0.60–0.80 g/cm³. Fiberboards were manufactured with three densities (0.60, 0.75, and 1.00 g/cm³). For softwood fiberboards, the bending properties for LCNF-mixed boards were higher than those for the control fiberboards at all densities. In this paper, control fiberboard means fiberboard with fiber only. For hardwood fiberboards, the bending properties for LCNF-mixed fiberboard for 1.00 g/cm³-density board were higher than those for the control fiberboard. For internal bond strength (IB), the IB for LCNF-mixed fiberboard was higher than that for the control fiberboard. The thickness swelling (TS) and weight change (WC) with water absorption for fiberboards containing LCNF were lower than those for control fiberboards. As a conclusion, physical and mechanical properties of the resulting fiberboards were significantly improved with the addition of LCNF, especially for softwood fiberboards, due to close binding between LCNF and wood fibers.     

Physical and mechanical properties of particleboard from roselle (Hibiscus sabdariffa) stalks and eucalyptus (Eucalyptus camaldulensis) wood particles

Abstract

The objective of this work was to evaluate the performance of particleboard manufactured from roselle (Hibiscus sabdariffa) stalks and eucalyptus (Eucalyptus camaldulensis) wood. The manufacturing parameters were various roselle (Hibiscus sabdariffa) ratios in the mixture (0, 25, 50, 75 and 100%) and press time (3, 5 and 7 min). Modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding (IB) strength values and thickness swelling (TS) after 24-hour water soaking of the panels were determined according to the procedure of European Union (EN) Standard. The results of the study demonstrate that roselle stalks can be an alternative raw material source for particleboard industry. With an increase of roselle particles from 0% to 100%, the TS was reduced, and the IB, MOR and MOE were increased. The highest MOE, MOR, IB strength and TS values of the samples were found as 2754.18, 16.81, 0.89 N/mm² and 15.26% for the panels made using 100% roselle with a 7-min press time, respectively.     

Effects of five additive materials on mechanical and dimensional properties of wood cement-bonded boards

There is a growing desire to improve the properties and use of nonwood plant materials as supplements to wood materials for wood cement-bonded boards (WCBs). This study was conducted to determine the comparative properties of WCBs containing various amounts of discontinuous inorganic fiber materials, such as alkali-resistant glass fiber, normal glass fiber, mineral wool, and nonwood plant materials such as retted flax straw and wheat straw particles. Tested cement-bonded boards were made at wood/additive compositions of 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (weight percentages). Seventy-eight laboratory-scale WCBs were produced. Various board properties, such as the modulus of rupture (MOR), internal bonding strength (IB), water absorption (WA), thickness swelling (TS), and linear expansion (LE), were studied. The test results showed that three types of discontinuous inorganic fiber used as reinforcing materials in composites significantly enhanced and modified the performance of WCBs. The mechanical properties and dimensional stability of cement-bonded board were significantly improved with increasing amounts of the additives. MOR and IB were increased; and WA, TS, and LE of boards were reduced by combination with the inorganic fiber materials. The results also indicated that combination with retted flax straw particles only slightly increased the MOR of boards, and wheat straw particles led to marked decreases in all the mechanical properties and the dimensional stability of WCBs.Part of this report was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000     

利用杨树人工林剩余物生产刨花板可行性研究

The composite board industry in Iran is obliged to use residues from forest operation as well as wood industry for competing with paper industry because of shortage of wood. In the present study we investigated the residues from poplar plantation used for particleboard production. Three kinds of wood materials, poplar branches, small diameter poplar wood (3–8 cm) and beech wood, were used in the experiment of particleboard production. The results demonstrated that the characteristic of particleboard made from poplar branches and small diameter wood is comparable to that made from mature beech wood. To avoid too much residual acid in the final board, the properties of boards produced with 1.5% hardener at 175°C press temperature are acceptable, although the properties of particleboard produced with 2% hardener were higher than were higher than that of the board produced with lower hardener (1% or 1.5%).. The MOR, MOE and IB of particleboard made from branches were measured as 14.57, 2015, and 1.32 MPa, respectively, while The MOR, MOE and IB of particleboard produced from small diameter poplar wood were 19.90, 2199, and 1.86 MPa, respectively. The thickness swelling of boards made from branches after 2 and 24 h immersion in water was 20.14% and 31.26%. The utilization of branches and very small diameter wood of poplar is recommended for the survival and developments of particleboard industry in Iran.     

Diversity,structure and standing stock of wood in the homegardens of Kerala in peninsular India

A survey was conducted in 17 selectedthaluks (revenue sub-divisions) of Kerala state to elucidate the floristic structure, composition and the extent of similarities and diversities in the composition of homegardens of Kerala, with particular reference to small (below 0.4 ha), medium (0.5 to 2 ha) and large (>2.0 ha) holding size categories. Besides attempts wer also made to characterize the potential of homegardens to supply commercial timber and fuelwood. Two hundred and fifty two farmers were selected through a stratified random process. In addition to gathering general information on crop and livestock production enterprises, all scattered trees and shrubs (15 cm girth at breast height) on the homestead and border trees except palms and rubber were enumerated.There was tremendous variability both in the number of trees and shrubs present and species diversity of the selected homesteads in different provinces. The small, medium and large sized holdings also exhibited profound variability in the number of woody taxa and individuals present. In total, 127 woody species (Girth at Breast Height (GBH) 15 cm) were encountered. The mean number of woody taxa found in the homegardens ranged from 11 for Pathanapuram to 39 in Perinthalmanna. Floristic diversity was higher in the smaller homesteads. It decreased with increasing the size of holdings. Mean Simpson's diversity index for the homesteads ranged from 0.251 (Kochi) to 0.739 (Kottarakkara) suggesting that floristic diversity of homegardens was moderate to low compared to a value over 0.90 for the species-rich evergreen forests of the Western Ghats. The Sorensen's similarity indexes suggested a moderately high degree of similarity for the different tree species encountered in the homesteads of Kerala.No clear cut planting pattern was discernible in the homegardens of Kerala. The homegarden trees and shrubs were either scattered throughout the homestead or on farm boundaries. Farmers tend to prefer timber trees such as ailanthus (highest frequency) and teak besides fruit trees such as mango, jack, cashew and the like. Major homegarden species were represented in all diameter classes. The diameter structure, however, exhibited a slightly skewed (+) distribution pattern, having the highest frequency in the 20–30 cm classes ensuring adequate regeneration status and in that process making homegardens a sustainable as well as dynamic land use system.Standing stock of timber and firewood in the homestead of differentthaluks are presented. Average commercial standing stock of homesteads ranged from 6.6 to 50.8 m³ ha^–1 and fuel wood volume was of the order of 23 to 86 m³ ha^–1. Implicit in the high commercial timber volume and fuel wood volume is that a substantial proportion of the society's wood demands are met from the homesteads. Palms, however, constituted the dominant component of standing commercial timber and fuel wood volumes accounting as much as 63% and 72%, respectively, of the total wood in these categories.     

Cement-bonded particleboard with a mixture of wheat straw and poplar wood

We investigated the hydration behavior and some physical/mechanical properties of cement-bonded particleboard (CBPB) containing particles of wheat straw and poplar wood at various usage ratios and bonded with Portland cement mixed with different levels of inorganic additives. We determined the setting time and compression strength of cement pastes containing different additives and particles, and studied the effects of these additives and particles on thickness swelling, internal bond strength and modulus of rupture of CBPB by using RSM (Response Surface Methodology). The mathematical model equations (second-order response functions) were derived to optimize properties of CBPB by computer simulation programming. Predicted values were in agreement with experimental values (R2 values of 0.93, 0.96 and 0.96 for TS, IB and MOR, respectively). RSM can be efficiently applied to model panel properties. The variables can affect the properties of panels. The cement composites with bending strength > 12.5 MPa and internal bond strength > 0.28 MPa can be made by using wheat straw as a reinforcing material. Straw particle usage up to 11.5% in the mixture satisfies the minimum requirements of International Standard, EN 312 (2003) for IB and MOR. The dose of 4.95% calcium chloride, by weight of cement, can improve mechanical properties of the panels at the minimum requirement of EN 312. By increasing straw content from 0 to 30%, TS was reduced by increasing straw particle usage up to 1.5% and with 5.54% calcium chloride in the mixture, TS satisfied the EN 312 standard.     

Effects of silane coupling agent level and extraction treatment on the properties of UF-bonded reed and wheat straw particleboards

Urea formaldehyde resin bonded reed and wheat particleboards with a density of 0.7g/cm³ were manufactured from two types of particle: fine and coarse particles. The effects of the silane coupling agent (SCA) level and ethanol-benzene (EB) treatment on the board properties were examined. For SCA, epoxide silane (SiEP) and amino silane (SiNH) were used for reed and wheat particles, respectively. The results are summarized as follows. (1) For both reed and wheat boards, the internal bond (IB) strength and thickness swelling (TS) were significantly improved at up to 5% SCA content, but the effectiveness of treatment kept constant at above 5%. (2) The level of SCA had little effect on the bending strength, especially for the boards composed of coarse particles. (3) EB treatment upgraded both the IB and TS of wheat board significantly. (4) SiEP incorporation improved the IB and TS of reed board significantly, whereas EB treatment was more effective for wheat board. (5) The dimensional stability of both reed and wheat boards under varying humidity could be improved by increasing the level of SCA and by EB treatment. EB treatment was more effective than SCA addition.     

The effects of chemical components and particle size on the mechanical properties of binderless boards made from oak (<Emphasis Type="Italic">Quercus</Emphasis> spp.) logs degraded by shiitake fungi <Emphasis Type="Italic">(Lentinula edodes</Emphasis>)

Binderless boards are composite boards that rely on self-bonding mechanisms for inter-fibre bonding. Quercus acutissima and Quercus serrata logs degraded by Lentinula edodes (shiitake fungi) were used in this study to investigate whether physical and chemical changes induced by shiitake fungi can enhance board mechanical properties. Binderless boards were manufactured with 0.8 g/cm³ target density, 220 °C pressing temperature, 5 MPa pressure, and pressing duration of 10 min. Boards made from logs degraded for ≥?26 months were stronger than control boards and met modulus of rupture (MOR) and internal bonding (IB) requirements for fibreboards. Chemical composition and particle size distribution of the wood powder used to make the boards were determined to elucidate the drivers of board mechanical properties. The proportion of small particles (<?150 µm) showed a strong positive correlation with MOR for both species and hot water extractives showed a strong positive correlation with IB for Q. acutissima boards. Introduction of shiitake fungi pre-treatment to the production process may enhance the mechanical strength of binderless boards.     

6种杉阔混交林造林效果的调查研究

对6种杉阔混交林的调查研究结果表明:6种混交林均取得良好混交效果,促进了杉木树高、直径生长,提高了林分蓄积量,混交林分蓄积量比杉木纯林大4.3%~27.9%.鄂西红豆树、红锥、格氏栲在速生杉木的促进和竞争下,顶端优势明显,分叉少,干形通直,可培育大径材.观光木、乳源木莲分别与杉木混交,种间关系协调,生长稳定.杉檫混交林有利于檫树生长稳定,培育大径材,但应对檫树混交比例加以控制,不宜过大.6种阔叶树均为杉木优良的伴生树种,可大力推广.     

Mechanical properties assessment of Cunninghamia lanceolata plantation wood with three acoustic-based nondestructive methods

The objectives of this study were to establish the method of evaluating wood mechanical properties by acoustic nondestructive testing at standing trees and at logs of a Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantation, and to compare three acoustic nondestructive methods for evaluating the static bending modulus of elasticity (MOE), modulus of rupture (MOR), and compressive strength parallel-to-grain (σ_c) of plantation wood as well. Fifteen Chinese fir plantation trees at 36 years of age were selected. Each tree was cut into four logs, for which three values of dynamic modulus of elasticity, i.e., E _sw, of the north and south face based on stress waves to assume the measuring state of the standing tree, E _fr, longitudinal vibration, and E _us, ultrasonic wave, were measured in the green condition. After log measurements, small specimens were cut and air-dried to 12% moisture content (MC). Static bending tests were then performed to determine the bending MOE and MOR, and compressive tests parallel-to-grain were made to determine σ_c. The bending MOE of small clear specimens was about 7.1% and 15.4% less than E _sw and E _us, respectively, and 11.3% greater than E _fr. The differences between the bending MOE and dynamic MOE of logs as determined by the three acoustic methods were statistically significant (P < 0.001). Good correlation (R = 0.77, 0.57, and 0.45) between E _sw, E _fr, and E _us and static MOE, respectively, were obtained (P < 0.001). It can be concluded that longitudinal vibration may be the most precise and reliable technique to evaluate the mechanical properties of logs among these three acoustic nondestructive methods. Moreover, the results indicate that stress wave technology would be effective to evaluate wood mechanical properties both from logs and from the standing tree.     

Physical and mechanical properties of Pinus leucodermis wood

Abstract

The present work reports on the main physical and mechanical properties of Pinus leucodermis mature wood, one of the least studied coniferous species in south-east Europe. Pinus leucodermis heartwood specimens were found to have average density values of 0.73 g cm^?3 at equilibrium moisture content of 11.5% and average density of 0.64 g cm^?3 under oven-dry conditions. The overall tangential shrinkage was 3.4% and the radial shrinkage was 1.9%. The modulus of rupture was on average 77 N mm^?2, while the static modulus of elasticity averaged 7087 N mm^?2. The hardness of P. leucodermis heartwood using the modified Janka test was 33.4 N mm^?2 in the transverse direction and 48.0 N mm^?2 in the longitudinal direction, while its compression strength parallel to grain was approximately 41.6 N mm^?2.     

Dendrometric analysis of olive trees for wood biomass quantification in Mediterranean orchards

This work focuses on the development of dendrometric algorithms to calculate the volume and total biomass contained in olive trees. This laid the foundation for the use of this methodology as a tool to manage resources from orchards, establishing adequate prediction models for assessing other parameters such as income from raw materials from the cultivation, fruit production, CO₂ sinks, and waste materials (residual wood) used for energy or industry. Dendrometry has traditionally been applied to forest trees. However, little research has been conducted on fruit trees because of their heterogeneous structure. This issue was the first step of this research. For this, the form factors were calculated. This relates to the actual volume of the branch with a model volume, calculated as a revolution solid from the base diameter and length. The shape more approximated to 1 was the cylinder model with a mean value of 0.76 and standard deviation (SD) of 0.23. On the other hand, volume equations were obtained for the branches. The distribution of biomass in the tree was analyzed. It is estimated that 40 % of biomass is located in the stem and 60 % in the crown, and most of the crown biomass is concentrated in the first branches (60 %). Afterwards, occupation factors were calculated to relate the wood volume in the crown to its apparent volume, the mean being 0.005 dm³/m³ and SD 0.0025 dm³/m³. Also, equations for predicting the whole wood in the crown were obtained. In this regard, the best results were obtained when the crown diameter was used (R ² = 0.74). These results could be correlated with the production and quality of the fruit, amount of residual biomass coming from pruning, and LIDAR data, which may indicate a simple, quick, and accurate method for predicting biomass.     

Manufacture of composite board using wood prunings and waste porcelain stone

The objective of this study was to develop a method for the effective use of both pruned wood and porcelain stone scrap. Thus, we manufactured a wood-porcelain stone composite board, which has excellent waterproof property and incombustibility properties. In addition, we examined the conditions needed to manufacture the wood-porcelain stone composite board as a construction material and evaluated the physical and mechanical properties of this board based on the Japanese Industrial Standard. The main results obtained were as follows: the wood-porcelain stone composite board made from pruned wood and porcelain stone scrap had excellent thickness swelling performance and the board had incombustibility properties that were better than commercial oriented strand board. In both single-layer and three-layer composite boards with weight ratios of porcelain stone particles of 40%, the internal bond strength exceeded the standard value of type 18 particleboard of JIS A 5908. However, the bending properties of the composite board were inferior to the type 18 particleboard standard. Therefore, it will be necessary to improve the bending properties of the board by changing the particle sizes of both the porcelain stone scrap and the pruned wood component. Part of this article was presented at the 57th Annual Meeting of the Japan Wood Research Society at Hiroshima, August 2007     

Effect of different drying methods on liquid penetration of Chinese fir plantation wood

Chinese fir plantation sapwood and heartwood boards were treated by three drying methods: radio frequency-vacuum drying (RFVD), conventional kiln drying (KD) and high temperature drying (HTD). The maximum amount of dyeing solution uptake by the capillary rising method was used to evaluate the liquid penetration of the treated wood. The pit aspiration ratio was determined by a semithin section method. Changes in wood microstructure were investigated using scanning electron microscopy. The results show that liquid penetration of Chinese fir sapwood after RFVD is significantly higher than that after KD and HTD. Liquid penetration of Chinese fir heartwood after RFVD is higher than that after HTD. Liquid penetration of Chinese fir sapwood is significantly higher than that of heartwood after three drying treatments. Low pit aspiration ratio and cracks of some bordered pits are the main reasons for the increase in liquid penetration after RFVD treatment. __________ Translated from Scientia Silvae Sinicae, 2006, 42(10): 85–90 [译自: 林业科学]     

Wood properties of teak (<Emphasis Type="Italic">Tectona grandis</Emphasis>) from a mature unmanaged stand in East Timor

The wood quality from 50- to 70-year-old Tectona grandis trees from an unmanaged forest in East Timor was assessed. The aim was to evaluate teak in mature stands that had undergone uncontrolled disturbances, e.g., fire and local community usage. Heartwood represented 91% of the tree radius at a height of 1.7 m, and sapwood contained on average nine rings. The mean ring width showed within-tree and between-tree variability. The chemical compositions of heartwood and sapwood were similar. Within-tree chemical variation occurred only in terms of extractives, which increased from the pith (8.3%) to the heartwood-sapwood transition (12.7%) and decreased in the sapwood (9.2%). Overall, the wood properties of teak from a unmanaged forest in East Timor were comparable to those reported for plantation teaks of other origin: 607 kg/m³ basic density, 3.5% and 5.2% radial and tangential shrinkage, 141 N/mm² modulus of rupture, 10684 N/mm² modulus of elasticity, and 50 N/mm² maximum crushing strength in compression parallel to the grain. Disturbances on individual tree growth arising from the unmanaged status of the stand were evidenced by higher within-tree variability of ring width. However, the longitudinal and radial variations of wood density and mechanical properties were of low magnitude and in a degree that did not negatively impact on timber quality.     

Leaching characteristics of homologues of benzalkonium chloride from wood treated with ammoniacal copper quaternary wood preservative

In Japan, ammoniacal copper quaternary wood preservatives type-1 (ACQ-1), which contains copper and benzalkonium chloride as its active ingredients, is among the most widely used wood preservatives in the pressure treatment of wood. Benzalkonium chloride (BAC) in commercial ACQ-1 products mainly comprises C12 and C14 homologues. In the present study, the leaching characteristics of these BAC homologues were investigated using the heartwood and sapwood portions of Japanese cedar, Japanese larch, and Sakhalin fir treated with ACQ-1 and 1% monoethanolamine (MEA) solution containing equimolar amounts of homologues. Distilled water (DW) and artificial seawater (SW) were used as leaching media. Consequently, it was observed that the leaching rate of the C12 homologue tended to be higher than that of the C14 homologue in DW. The leaching of C12 homologues was accelerated by using SW, resulting in a significantly higher leaching rate than the C14 homologue using SW. It was thought that the difference in the hydrophobicities based on alkyl chain lengths resulted in these phenomena. However, when the heartwood portion of Japanese larch was treated with the homologues in MEA, the leaching rate of the C14 homologue was significantly higher than that of the C12 homologue.     

Vessel size and number are contributors to define wood density in cork oak

Cork oak (Quercus suber L.) has a dense wood that allows high-quality uses. In the present work, we study the influence of vessel characteristics, measured through image analysis and optical microscopy, on wood density, measured using X-ray microdensitometry, on 40-year-old trees. Vessel area increases with cambial age (5403–33064 μm²), while wood density decreases (1.229–0.836 g/cm³). The number of vessels is relatively constant at 6 vessels/mm², while vessel proportion in cross-section increases from 3.3% near the pith to 20.5% near the bark. In growth rings closest to the pith, with high wood density and low vessel area, the relationship between the two variables is linear (R ² = −32.1%, P < 0.01) but with increasing tree age and vessel size, the wood density remains rather constant, suggesting that decreases in density might compromise mechanical support of the tree at a stage when the increase in cross-sectional area alone might not provide mechanical stability. Other anatomical characteristics not considered in this study, like large xylem rays that increase with cambial age, may be responsible for the constant density.     

Structural mechanics of wood composite materials 11: Ultrasonic propagation mechanism and internal bonding of particleboard

Ultrasonic nondestructive evaluation (NDE) methods have been successfully applied for grading lumber and veneer at the in-plant level. To expand this application in wood composite production, further research is needed to elucidate the effect of differences of component elements within wood composite panels on the behavior of ultrasonic waves traveling through them. The objective of this study was to investigate the effects of the internal bonding of particleboard specimens containing component chips of different geometry on ultrasonic velocity. Commercial chips screened at four sizes were used to produce particleboard specimens with different internal bonding by controlling their out-of-press thickness at (a) a constant thickness for boards made of each chip size, and (b) four different thicknesses for boards made of the same chip size. Twenty-four boards were made with phenol-formaldehyde (PF) resin at 8% solid resin content in our laboratory. After the velocities of the waves traveling through the thickness of the boards were recorded, the internal bond strengths were tested. Results showed the density, internal bond state, and constituted chip geometry were the main factors influencing the velocity. NDE using ultrasonic waves is an available method to evaluate the internal bonding of particleboard with a density less than about 0.75g/cm³. With densities over that value, no significant changes of the velocity were found.Part of this paper was presented at the 48th annual meeting of the Japan Wood Research Society, Kochi, April 1998     

Medium-density fiberboard performance as affected by wood fiber acidity, bulk density, and size distribution

The properties of medium-density fiberboard (MDF) panels as affected by wood fiber characteristics were investigated. Wood chips from three softwood and one hardwood species were refined under the same refining conditions to make four different types of fibers. The resulting fibers were characterized by fiber size distribution, bulk density, pH value, and buffering capacity. Using the same resin system and hot-pressing parameters, MDF panels were produced and evaluated for internal bonding (IB), modulus of rupture (MOR), modulus of elasticity (MOE), thickness swelling, and linear expansion. The pH values and alkaline buffering capacities of raw materials were reduced considerably after refining. IB was strongly related to the pH value of fibers. The mechanical properties increased with alkaline buffering capacity. IB, MOR, and MOE increased with the bulk density of fibers. Increased proportions of coarse fibers had negative effects on the panel mechanical properties.