The effects of heat treatment on technological properties in Red-bud maple (Acer trautvetteri Medw.) wood

Heat treatment is often used to improve the dimensional stability of wood. In this study, the effects of heat treatment on technological properties of Red-bud maple (Acer trautvetteri Medw.) wood were examined. Samples obtained from Düzce Forest Enterprises, Turkey, were subjected to heat treatment at varying temperatures (120 degrees C, 150 degrees C and 180 degrees C) and for varying durations (2h, 6h and 10h). The technological properties of heat-treated wood samples and control samples were tested. Compression strength parallel to grain, bending strength, modulus of elasticity in bending, janka-hardness, impact bending strength, and tension strength perpendicular to grain were determined. The results showed that technological strength values decreased with increasing treatment temperature and treatment times. Red-bud maple wood could be utilized by using proper heat treatment techniques with minimal losses in strength values in areas where working, and stability such as in window frames, are important factors.     

The effects of heat treatment on physical and technological properties and surface roughness of Camiyani Black Pine (Pinus nigra Arn. subsp. pallasiana var. pallasiana) wood

Heat treatment is often used to improve the dimensional stability of wood. In this study, the effects of heat treatment on physical properties and surface roughness of Camiyani Black Pine (Pinus nigra Arn. subsp. pallasiana var. pallasiana) wood were examined. Samples obtained from Yenice-Zonguldak Forest Enterprises, Turkey, were subjected to heat treatment at varying temperatures and for varying durations. The physical properties of heat-treated and control samples were tested, and oven-dry density, air-dry density, and swelling properties were determined. The mechanical properties of heat-treated and control samples were tested, and compression strength, and Janka-hardness were determined. A stylus method was employed to evaluate the surface characteristics of the samples. Roughness measurements by the stylus method were made in the direction perpendicular to the fiber. Four main roughness parameters, mean arithmetic deviation of profile (Ra), mean peak-to-valley height (Rz), root mean square roughness (Rq), and maximum roughness (Ry) obtained from the surface of wood were used to evaluate the effect of heat treatment on the surface characteristics of the specimens. Significant difference was determined (p=0.05) between physical and technological properties, and surface roughness parameters (Ra, Rz, Ry, Rq) for three temperatures and three durations of heat treatment. Based on the findings in this study, the results showed that density, swelling, compression strength, Janka-hardness and surface roughness values decreased with increasing treatment temperature and treatment times. Increase in temperature and duration further diminished technological strength values of the wood specimens. Camiyani Black Pine wood could be utilized by using proper heat treatment techniques without any losses in strength values in areas where working, stability, and surface smoothness, such as in window frames, are important factors.     

The effects of heat treatment on physical properties and surface roughness of red-bud maple (Acer trautvetteri Medw.) wood

Heat treatment is often used to improve the dimensional stability of wood. In this study, the effects of heat treatment on physical properties and surface roughness of red-bud maple (Acer trautvetteri Medw.) wood were examined. Samples obtained from Düzce Forest Enterprises, Turkey, were subjected to heat treatment at varying temperatures and durations. The physical properties of heat-treated samples were compared against controls in order to determine their; oven-dry density, air-dry density, and swelling properties. A stylus method was employed to evaluate the surface characteristics of the samples. Roughness measurements, using the stylus method, were made in the direction perpendicular to the fiber. Three main roughness parameters; mean arithmetic deviation of profile (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax) obtained from the surface of wood, were used to evaluate the effect of heat treatment on the surface characteristics of the specimens. Significant differences were determined (p>0.05) between surface roughness parameters (Ra, Rz, Rmax) at three different temperatures and three periods of heat treatment. The results showed that the values of density, swelling and surface roughness decreased with increasing temperature treatment and treatment times. Red-bud maple wood could be utilized successfully by applying proper heat treatment techniques without any losses in investigated parameters. This is vital in areas, such as window frames, where working stability and surface smoothness are important factors.     

Mechanical properties and decay resistance of wood-polymer composites prepared from fast growing species in Turkey

Some mechanical properties of wood-polymer composites from maritime pine (Pinus pinaster Ait.) and poplar (Populus x. euramericana cv. I-214) wood were investigated. Three different monomers; styrene (ST), methyl methacrylate (MMA) and styrene/methyl methacrylate (ST/MMA) mixture were used in preparation of wood-polymer composites (WPCs). Full-loading (FL), half-loading (HL) and quarter-loading (QL) were used as polymer content levels. Untreated pine and pine-polymer composite samples were tested in compression strength parallel to grain and static bending strength. WPCs mechanical properties increased compared to untreated wood. The polymer had greater effect on the strengths of the ST/MMA treated pine than on the ST and MMA treated pine samples. Increasing of the mechanical properties should improve the structural competitiveness of WPCs made from fast growing-low density woods. Weight losses due to fungal attack for pine and poplar-polymer composites were also determined. Although polymers at full and half loading levels helped decreasing weight losses due to both fungi for each wood species, weight losses were still found to be higher.     

Bending properties of wood treated with a new organic wood preservative system

This study investigated the effect of treatment of southern pine with a new generation, all organic wood preserving system on the mechanical properties in bending. Static bending tests showed no deleterious effects of treatment on property values when compared with untreated controls. Values for samples treated to 0.774 kg/m(3) total active ingredients (ai) were lower when compared to a lower retention (0.184 kg/m(3)) or to a standard copper azole system, but were not different than water-treated controls.     

Physical and mechanical properties of European Hophornbeam (Ostrya carpinifolia Scop.) wood

The main purpose of the study was to determine some physical and mechanical properties of European Hophornbeam (Ostrya carpinifolia Scop.) wood of which is not any detailed previous research in the literature. The sample trees harvested from a mixed beech-oak-hornbeam stand in the Zonguldak Forest Enterprises, north western part of Turkey. Conventional methods followed and the test procedures were performed on small clean specimens. European Hophornbeam wood's air dry and over dry densities were determined as 890 and 853 kg m(-3); density value in volume (basic density) was determined as 671 kg m(-3); volumetric shrinkage and swelling were determined as 23.02% and 24.94%; Fiber saturation point (FSP) was found 34.21%; MOR, MOE, compression strength parallel to grain, impact bending, tensile strength parallel and perpendicular to grain, and Janka hardness values (parallel and perpendicular to grain) were determined as 131.50 N/mm2, 11501.06 N/mm2, 66.94 N/mm2, 18.66 N/mm2, 105.49 N/mm2, 7.11 N/mm2, 6.89 and 5.63 kN, respectively.     

Preventive action of organosilicon treatments against disfigurement of wood under laboratory and outdoor conditions

Organosilicons and biocides with known effectiveness against fungal disfigurement were used for dipping or impregnating Scots pine sapwood specimens. All specimens were artificially or naturally weathered and the colour of all specimens was determined with a spectrophotometer at fixed times. After artificial weathering the specimens were used in blue stain tests according to EN 152 or according to the EN 152 reverse method. The naturally exposed specimens were inspected for fungal disfigurement on their back side. Although the results learn that the coating approach is far better than the wood preservatives approach for evaluating blue stain attack of organosilicon-treated wood, organosilicons fail to protect wood under laboratory conditions. Outdoor exposure, however, revealed that organosilicon impregnated specimens were better protected against fungal disfigurement. The addition of a biocide improves the performance. Artificially aged specimens did not show significant colour differences compared to untreated Scots pine sapwood, while naturally aged specimens did, depending on the treatment conditions and presence of biocides. Organosilicons are able to reduce leaching of (degraded) wood constituents, leading to fewer colour changes compared to untreated scots pine and to decreased availability of nutrients for superficial fungal growth.     

Performance of oak,beech and spruce beams after more than 100 years in service

The aim of this study was to investigate differences in the mechanical and fungicidal properties of three different wood species (English oak (Quercus sp.), common beech (Fagus sylvatica) and Norway spruce (Picea abies)) that had been in indoor use for several decades, compared to control specimens of freshly cut timber. The collected material was cut into smaller samples prior to further analysis. Extractive content, mechanical, fungicidal and sorption properties were determined according to standard procedures. The obtained results showed that the mechanical properties of oak wood do not deteriorate over the investigated time frame. On the other hand, the resistance of oak wood against fungi decreases over time. The reason for this is yet to be confirmed; it may be due to degradation of secondary metabolites. Similar results have been reported for spruce wood. There were no statistically significant differences in the mechanical properties of old and new spruce wood. In contrast to oak wood, there were also no significant differences in fungicidal properties, bearing in mind that spruce wood has lower durability than oak wood. Aging of beech wood resulted in a considerable decrease in the tested mechanical properties but showed no significant differences in fungicidal properties. Old beech wood specimens were moderately deteriorated by insects and fungi, which was the reason for the loss of bending and compressive strength. Our results confirm that most of the relevant properties do not deteriorate with time and that wood can be reused for a variety of other applications even after decades in service.     

Determination of fungal activity in modified wood by means of micro-calorimetry and determination of total esterase activity

Beech and pine wood blocks were treated with 1,3-dimethylol-4,5-dihydroxyethylen urea (DMDHEU) to increasing weight percent gains (WPG). The resistance of the treated specimens against Trametes versicolor and Coniophora puteana, determined as mass loss, increased with increasing WPG of DMDHEU. Metabolic activity of the fungi in the wood blocks was assessed as total esterase activity (TEA) based on the hydrolysis of fluorescein diacetate and as heat or energy production determined by isothermal micro-calorimetry. Both methods revealed that the fungal activity was related with the WPG and the mass loss caused by the fungi. Still, fungal activity was detected even in wood blocks of the highest WPG and showed that the treatment was not toxic to the fungi. Energy production showed a higher consistency with the mass loss after decay than TEA; higher mass loss was more stringently reflected by higher heat production rate. Heat production did not proceed linearly, possibly due to the inhibition of fungal activity by an excess of carbon dioxide.     

Scots pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.) wood properties in an alkaline air pollution environment

This paper examines the long-term influence on pine (Pinus sylvestris L.) wood properties of alkaline dust pollution (pH 12.3–12.7) emitted over 135 years from a cement plant in Estonia. A study of stemwood physical and mechanical properties in 70–80-year-old Scots pines growing in three zones of different air pollution levels showed serious deviations in comparison with a relatively healthy forest in an unpolluted area. Specimens from polluted trees evidenced smaller sapwood annual ring widths than those from the control trees. At the same time, the number of growth rings in sapwood at breast height increased under pollution. In the polluted areas, percentage of latewood in the annual ring widths was higher than in the unpolluted area. Small amounts of cement dust, which contains elements essential for the mineral nutrition of the trees, might have acted as fertilizer. Pine wood in the polluted stands exhibited increased density, bending strength across the grain, compression strength along the grain and, in some instances, hardness along the grain.     

Evaluation of mold,decay and termite resistance of pine wood treated with zinc- and copper-based nanocompounds

In this work, the resistance of black pine wood (Pinus nigra L.) vacuum-treated with zinc oxide, zinc borate and copper oxide nanoparticles against mold and decay fungi and the subterranean termites was evaluated. Some of the nanocompounds tested were forced with acrylic emulsions to avoid leaching. Results showed that mold fungi were slightly inhibited by nanozinc borate, while the other nanometal preparations did not inhibit mold fungi. Mass loss from fungal attack by Trametes versicolor was significantly inhibited by the zinc-based preparations, while the brown-rot fungus, Tyromyces palustris was not inhibited by the nanometal treatments. Notably, nanozinc borate plus acrylic emulsion imparted very high resistance in pine wood to the white-rot fungus, T. versicolor with a mass loss of 1.8%. Following leaching, all pine specimens treated with nanozinc borate, with or without acrylic emulsion, strongly inhibited termite feeding, i.e. mass losses varying at 5.2–5.4%. In contrast, the copper-based treatments were much less effective against the subterranean termites, Coptotermes formosanus. In general, nanozinc borate possessed favorable properties, that is, inhibition of termite feeding and decay by T. versicolor.     

On the Taxonomy and Morphology of the Pine Wood Nematode, Bursaphelenchus xylophilus (Steiner &Buhrer 1934) Nickle 1970

During the past 3 yr, nematologists in the United States have found specimens of Bursaphelenchus sp. in the wood of dead and dying pine trees. This nematode-host association resembles a similar interaction reported from Japan where pine trees are being killed by the pine wood nematode. This taxonomic research was conducted to determine if the Japanese pine wood nematode and similar populations in the United States are of the same species. Based upon typical morphological characters of original specimens of Bursaphelenchus xylophilus (Steiner and Buhrer 1934) Nickle 1970 that were rediscovered in the USDA Nematode Collection and genetic crosses among the Japanese and American nematode populations, it was concluded that they are all the same species, B. xylophilus.     

Azole-based antimycotic agents inhibit mold on unseasoned pine

Inhibiting the growth of mold fungi on cellulose-based building materials may be achievable through the use of azole-based antimycotics. Azoles were variably effective against mold fungi that are frequently found on wood and wood products. Unseasoned southern yellow pine specimens that were dip-treated with varying concentrations of eight azoles were evaluated for their ability to resist mold infestation when challenged with Aspergillus niger, Penicillium chrysogenum, and Trichoderma viride spores. Minimal fungicidal concentrations (MFC₉₀) were determined to be 0.016% for thiabendazole and 0.043% for voriconazole, the most efficacious azoles against the challenge fungi. We conclude that thiabendazole or voriconazole may be used alone or in combination to inhibit mold fungi on unseasoned pine.     

Flexural properties of repaired heat‐polymerising acrylic resin after wetting with monomer and acetone

doi:10.1111/j.1741‐2358.2009.00321.x
Flexural properties of repaired heat‐polymerising acrylic resin after wetting with monomer and acetone Objectives: Repair strength can be improved by treating fractured surfaces of a denture. Background: This study investigated flexural properties of heat‐polymerised acrylic resin specimens repaired with auto‐polymerising and visible light curing (VLC) resins after the repair surfaces were wetted with monomers or acetone. Materials and Methods: Fifty‐four specimens (65 × 10 × 2.5 mm) were prepared and 48 of them were sectioned to simulate denture fracture. Butt‐joint designed repair surfaces were wetted with heat‐, auto‐polymerising monomers and acetone for 180 s and repaired with auto‐polymerising and VLC resins. After repairs, specimens were subjected to three‐point bending test and flexural strength, strain, fracture load, modulus of elasticity and deflection values were recorded. Data were analysed with Student t and LSD tests (p ≤ 0.05). Results: Overall flexural strength, strain, fracture load and deflection values of specimens repaired with VLC resin were significantly higher than the specimens repaired with auto‐polymerising resin for all types of wetting agent (p < 0.05). Within the wetting agents, heat‐ and auto‐polymerising monomers produced the best mechanical properties, while wetting with acetone did not provide superior effect over both monomers. Conclusion: In clinical use, wetting the repair surfaces may result in stronger repairs. The use of bonding agent in VLC resin repairs in combination with wetting agent results in improved flexural properties.     

Effect of forest thinning and wood quality on the short-term wood decomposition rate in a <Emphasis Type="Italic">Pinus tabuliformis</Emphasis> plantation

The effects of forest thinning and wood quality on wood decomposition in the mineral soil were investigated in a Chinese pine (Pinus tabuliformis Carriére) plantation in northern China by measuring mass loss and changes in wood properties (carbohydrates, lignin and nitrogen (N) concentrations) in wood stakes of two tree species—loblolly pine (Pinus taeda L.) and trembling aspen (Populus tremuloides Michx.). Stakes were inserted to a 20 cm soil depth in stands with three thinning levels (low, moderate, and heavy) and an unharvested control and removed after 1 year. There were significant differences in stake mass loss among the treatments. The species effect on the stake mass loss was marginally significant. Wood N content of both species increased during decomposition in all thinning treatments, and was only correlated with aspen mass loss. Wood properties of stakes placed in each stand before insertion (t?=?0) were similar, except for pine lignin concentration and aspen lignin: N ratio, but neither had any effect on thinning treatment results. Lignin concentration increased and carbohydrate concentration decreased in both aspen and pine wood stakes during decomposition across all thinning treatments, which suggests that brown-rot fungi are dominant wood-decomposers on our study site. We conclude that thinning has a significant influence on the wood decomposition in the mineral soil of this Chinese pine plantation.     

Fluorescence Microscopy for Measuring Fibril Angles in Pine Tracheids

Observation and measurement of fibril angles in increment cores or similar small samples from living pine trees was facilitated by the use of fluorescence microscopy. Although some autofluorescence was present, brighter images could be obtained by staining the specimens with a 0.1% aqueous solution of a fluoro-chrome (Calcozine Ha vine TG extra concentrated, Calcozine red 6G extra, rhodamine 6G, rhodamine 6GD extra, or a succession of flavine and rhodamine). Staining for 2—5 min followed by a 5-10 sec washing in distilled water and drying 15 min at 190-195°C prepared radially split surfaces of specimens for microscopic observation with ultraviolet light. Measurement of fibril angles, important for the determination of wood strength and the properties of its pulp, was made with a protractor eyepiece. Photomicrography was feasible also, and the need of preparing microtome sections was obviated.     

Still rethinking the value of high wood density

? Premise of the study: In a previous paper, we questioned the traditional interpretation of the advantages and disadvantages of high wood density (Functional Ecology 24: 701-705). Niklas and Spatz (American Journal of Botany 97: 1587-1594) challenged the biomechanical relevance of studying properties of dry wood, including dry wood density, and stated that we erred in our claims regarding scaling. ? Methods: We first present the full derivation of our previous claims regarding scaling. We then examine how the fresh modulus of rupture and the elastic modulus scale with dry wood density and compare these scaling relationships with those for dry mechanical properties, using almost exactly the same data set analyzed by Niklas and Spatz. ? Key results: The derivation shows that given our assumptions that the modulus of rupture and elastic modulus are both proportional to wood density, the resistance to bending is inversely proportional to wood density and strength is inversely proportional with the square root of wood density, exactly as we previously claimed. The analyses show that the elastic modulus of fresh wood scales proportionally with wood density (exponent 1.05, 95% CI 0.90-1.11) but that the modulus of rupture of fresh wood does not, scaling instead with the 1.25 power of wood density (CI 1.18-1.31). ? Conclusions: The deviation from proportional scaling for modulus of rupture is so small that our central conclusion remains correct: for a given construction cost, trees with lower wood density have higher strength and higher resistance to bending.     

Resistance of Scots pine wood to Brown-rot fungi after long-term forest fertilization

The susceptibility of Scots pine (Pinus sylvestris L.) sap- and heartwood against the wood decaying brown-rot fungus (Coniophora puteana) was investigated after long-term forest fertilization at three different sites in central Finland. Different wood properties: wood extractives, wood chemistry, and wood anatomy were used to explain sap- and heartwood decay. Scots pine sapwood was more susceptible to decay than its heartwood. In one site, sapwood seemed to be more resistant to wood decay after forest fertilization whereas the susceptibility of heartwood increased. Significant changes in the sapwood chemistry were found between treatment and sites, however, no relationship between wood chemistry and wood decay was observed in the factor analysis. The results of this study show that there was an inconsistent relationship between decay susceptibility and fertilization and the measured physical and chemical attributes of the wood were not consistently correlated with the decay rate.     

Wood borer performance and wood characteristics of drought‐stressed Scots pine seedlings

Four‐year‐old Scots pine [Pinus sylvestris L. (Pinaceae)] seedlings were exposed to medium and severe drought stress for two consecutive years. The anatomical properties of drought‐stressed Scots pine wood and their impact on the performance of destructive wood boring early instars of Hylotrupes bajulus L. (Coleoptera: Cerambycidae) were studied. Drought stress significantly decreased diameter of earlywood tracheids in both growing years and diameter of latewood tracheids after the second growing season only. Cell lumen area was significantly decreased by both medium and severe drought stress compared to well‐watered controls. In addition, area of cell lumen was significantly smaller in severe drought than in medium drought treatment. The drought stress marginally increased the number of resin canals in the wood, but did not affect the size of resin canals either in wood or bark. The relative growth rate of xylophagous H. bajulus neonatal larvae was not significantly affected by drought stress during the 106‐day feeding period on Scots pine wood blocks. The results show that although water availability was an important factor affecting the development and anatomy of wood cells, observed changes in wood characteristics did not affect the performance of early instars feeding on wood processed from drought‐stressed young Scots pine seedlings.