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Timber industries make an essential contribution to economies worldwide, while the sustainable supply of timber generates revenue, supports employment, and contributes to economic activity. The strategic choice of wood species using specific criteria can have substantial economic outcomes for the timber industry in Greece. This study assessed the suitability of hardwood species most commonly used by Greek timber industries. The assessment was conducted with the use of a Multiple-Criteria Decision Analysis approach, taking into consideration specific criteria that affect the quality of timber. According to the findings, walnut was the optimal alternative that outranked the other examined species. Chestnut, oak, beech, ash, and hornbeam also achieved positive scores, and therefore, they are also acceptable alternatives as broadleaved species suitable for furniture manufacturing and sawn timber production. Greek timber industries can enhance their products’ value and market appeal by focusing on species that meet high-quality standards and consumer preferences.

A study was conducted to improve the effectiveness of silvicultural production of structural sawn timber from softwoods. It intends to explore prediction methods for mechanical timber quality. The study material was obtained from six stands divided into age groups of approximately 40- and 80-year-old trees (examining the influence of age). The stands were differentiated by their applied thinning system of thinning from below or above (examining the influence of the thinning system). Resulting from these different levels of data, i.e., stand parameters, tree anatomy, and visual board properties are examined and analyzed in ordinal logistic models and linear mixed models. Visual board properties were discerned by means of the German standard for visual grading of sawn timber. The mechanical board properties were measured in on-edge bending strength tests and allocated into strength classes, which were modeled in dependence of visual characteristics and forestry conditions. The evaluation of mechanical properties attributed a significant loss of timber quality to short rotation periods, non-ideal water supply, and a single-tree management system. The prediction capabilities of models based on site and tree characteristics were on par with the accuracy of visual grading. Management adaptations by intense thinning from above can lead to a significant decline in Norway spruce (Picea abies L.) timber quality when site factors coincide. Particular care should be taken in the management of locations with high yield potential. Non-destructive evaluation based on site characteristics combined with terrestrial laser scan data of tree characteristics has potential as a pregrading method. [ABSTRACT FROM AUTHOR]

Sawn-timber drying is the wood industry's most time- and energy-consuming process. This process can be more efficient than the conventional method by elevating the dry-bulb temperature to above 100 °C in a high-temperature drying (HTD) process, which for some species shortens the drying process by up to 50% without deteriorating the quality. Comprehending the complex correlation between the wood drying physics at high temperatures and the anatomical features of the specific species, along with its mechanical and physical properties, is crucial, as it limited its application from being broadly implemented in industry and the necessity of generalizing this method for wood species. The present study has been conducted to comprehensively review and tackle the challenges of applying this method on various species and the consequences, such as high moisture content gradients resulting in stress residual, unevenness, and color changes. Energy, environment, and economic (3E) assessments of HTD were evaluated. The accelerated drying process in HTD reduces heat losses and air leaks, resulting in higher energy efficiency than the conventional methods. Furthermore, it was proved to be 20% economically in the long term. Confliction in reported studies, such as HTD's effect on permeability and volatile organic compound (VOC) emissions, was raised, highlighting the importance of further studies for generalizing this method to adapt appropriate drying schedules, focusing on Scandinavian species by referring to previous industrial trials. [ABSTRACT FROM AUTHOR]

Surface defect detection of sawn timber is a critical task to ensure the quality of wooden products. Current methods have challenges in considering detection accuracy and speed simultaneously, due to the complexity of defects and the massive length of sawn timbers. Specifically, there are scale variation, large intraclass difference and high interclass similarity in the defects, which reduce the detection accuracy. To overcome these challenges, we propose an efficient multilevel-feature integration network (EMINet) based on YOLOv5s. To obtain discriminative features of defects, the cross fusion module (CFM) is proposed to fully integrate the multilevel features of backbone. In the CFM, the local information aggregation is designed to enrich the detailed information of high-level features, and the global information aggregation is designed to enhance the semantic information of low-level features. Experimental results demonstrate that the proposed EMINet achieves better accuracy with fast speed compared with the state-of-the-art methods. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the effect of layout modification on operational efficiency, productivity, and yield in two wood machining lines for planks, beams, rafters, boards, and battens of Eucalyptus spp. Daily production data was collected from the two machining lines over a period of 21 days, before and after the layout modification. For the calculation of operational efficiency, productivity, and yield, data on raw material volume and final product was used. The average operational efficiency of line one increased by 0.1534 m³.op.h-1, and line two by 0.1850 m³.op.h-1 after the layout modification. The productivity of lines one and two also increased after the restructuring, with differences of 0.1364 m³.op.h-1 and 0.1099 m³.op.h-1, respectively. The wood machining yield did not differ between the two lines. The results indicated production homogenization and performance improvement in wood machining. [ABSTRACT FROM AUTHOR]

Wood density plays an important role in the calculation of national carbon stock, specifically when employing production approach to observe the carbon stock change based on national production of harvested wood products. Density is used as one of the parameter for estimating the carbon stock and annual carbon change in the harvested wood products pools. In this study, the commodity data, sawn timber productions from year 1995 to 2020, were gathered from published annual statistics by Forestry Statistics Peninsular Malaysia. These data include all the commercial timbers in Peninsular Malaysia, which are grouped according to trade names. Efforts were made to correctly identify and compile the botanical name as well as density range and mean of each timber trade name according to published references. Basic density and total volume of sawn timber productions were used to calculate the weighted average wood density of Malaysian timber. The estimated volume-weighted average wood density (563 kg m-3) was comparable to the arithmetic mean (559 kg m-3) and published density value for tropical species (590 kg m-3) by Intergovernmental Panel on Climate Change 2006. [ABSTRACT FROM AUTHOR]

Heat-treated wood has good dimensional stability, durability, and color, but its susceptibility to fungal growth affects its commercial value. In this study, lumber harvested from mature Masson's pine (Pinus massoniana Lamb.) was vacuum impregnated with a basic copper salt solution (copper hydroxide, diethanolamine, and polyethylene glycol 200) prior to heat-treatment at 220°C for 3 h. Antifungal properties, surface chemistry, crystal structure and sugar contents were tested, compared with heat treatment alone. The results showed that the samples treated by heating without copper salt treatment showed poor suppression of fungal growth, the copperimpregnated heat-treated wood suppressed (100%) the growth of Botryodiplodia theobromae Pat., Aspergillus niger V. Tiegh., Penicillium citrinum Thom, and Trichoderma viride Pers. The combined results of X-ray photoelectron spectroscopy, X-ray diffraction and sugars analysis suggested that fungal inhibition by the heat-treated copper-bearing Masson's pine was mainly due to the reduction of the metal salt by PEG200 at high temperature to generate copper nanoparticles. In addition, the reduced sugar content of the treated timber, and hence the nutrient substrate for spoilage microbes, reduced in the presence of the metal salts at high-temperature. This study has demonstrated an effective method of increasing low-grade wood's utility and commercial value. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of ultrasonic densification technology on the surface hardness of the following wood species: aspen (Populus tremula), Scots pine (Pinus sylvestris) linden (Tilia europaea), alder (Alnus glutinosa), and oak (Quercus robur). The machine realising the proposed technology consists of an ultrasonic module and an infeed system that allows the treatment of sawn timber. The densification was achieved by feeding sawn timber specimens once through a pair of opposing ultrasonic sonotrodes, with the gap between them being smaller than the specimen thickness. This and the direct contact between the sonotrodes and the specimens led to an increase in density in the surface region and an increase in surface hardness, measured by the Leeb method. The internal structure was not damaged by the ultrasonic treatment. The simplicity of the process and the processing speed of several meters per minute merit further investigations of the technology. [ABSTRACT FROM AUTHOR]

This paper proposes a one-dimensional convolutional long short-term memory (1D-CNN-LSTM) model for estimating the pith position and average ring width in Norway spruce timber boards. The model predicts these cross-sectional parameters by processing sequences of light-intensity signals derived from optical scans of the board's four surfaces. The dataset used for training the model consists of synthetic boards sawn from simulated 3D logs. The model was evaluated on a dataset consisting of 552 end cross-sections from actual Norway spruce boards. Comparisons between the automatic and manual pith and ring width estimations demonstrated a very good accuracy. The computational speed of the model was more than twice as fast as the quickest method available in the literature. A large set of boards was then used to determine the advantages of incorporating the automatically determined average ring width in formulating indicating properties for machine strength grading. This evaluation revealed that the average ring width could, in certain situations, compensate for unknown variables such as density or resonance frequency in predicting the tensile and bending strength of Norway spruce boards. • New model for estimating the cross-sections of timber boards from surface images. • A 1D-CNN-LSTM was trained to predict both pith location and average ring width. • The model was trained on synthetic timber boards. • The model was validated on a large dataset of real Norway spruce boards. • Average ring width predicted by the model can improve strength predictions. [ABSTRACT FROM AUTHOR]

Chemical modification of wood typically requires the impregnation of wood with reactive compounds capable of undergoing covalent bonding to functional groups present in the cell wall. Creating such reactive agents in situ, with the use of low-priced chemicals, would prove more attractive for commercial applications. In this study, Scots pine (Pinus sylvestris L.) sapwood was impregnated with an aqueous solution of urea (30%), dried at 40°C for 24 h, and subsequently heat treated in an oven at 150°C for 24 h to produce the reactive isocyanic acid. By using accelerated fungal tests under laboratory conditions, provisional tests demonstrated a high biological resistance against selected moulds and rots. Migration of urea into the wood structure and grafting to its polymers during subsequent heat treatment, led to a bulked cell wall and enhanced resistance to water swelling, even after cycling water treatments. The bending strength (MOR) of modified pine wood was reduced by the treatment applied, while its modulus of elasticity (MOE) remained unchanged. [ABSTRACT FROM AUTHOR]

Background--In Sino-US trade frictions, China imposed tariffs on some timber imports from the United States, which inhibited the import of American timber. With the abolition of tariffs, it will inevitably have an impact on the imports of China's sawn timber and log. ⑵ Methods--Based on the monthly data of sawn timber and log imports in China from January 2010 to February 2021. In this paper, the dynamic Rotterdam model is used to calculate the compensation price elasticity and non-compensation price elasticity of China's import demand for sawn timber and log from different countries. (3) Results--①In terms of the compensation cross-price elasticity of various wood products from different sources, the cross-price effects of wood products from different countries in the short / long term are all complementary. ②China's timber import elasticity of expenditure is remarkable, and sawn timber import market concentration will decline in the long term. In the future, China will increase imports of log from New Zealand, Russia and the United States, and the import market will be more concentrated. ③China's demand elasticity for American log imports is flexible, and China will greatly increase its imports of American log. In the long run, China will increase the import dependence on American log and sawn timber, especially on American log. ④ With the exception of Thailand sawn timber, China's self-price elasticity of imports of sawn timber and log from other countries is positive and inelastic, indicating a modest increase in China's import demand for these timber products as prices rise. ⑤The core competition of future timber market is not price competition, but market share. The core competition factors are stable supply-demand relationship and stable trade policy. ⑷ Conclusions and Discussions--With the increasingly prominent contradiction between supply and demand of sawn timber and log in China, timber import demand will continue to grow. In the long run, China will reduce imports of Russian sawn timber, and sawn timber import market concentration will decline. In terms of China's sawn timber and log import market, as China's demand for imported timber continues to increase, imported sawn timber and log products will appear Giffen effect. The core competitiveness of China's imported timber market is not price competition. The stable timber supply and stable timber trade policies of exporting countries have a greater impact on China's timber imports. In addition, China imposes tariffs on imports of U. S. timber in trade frictions, which have a significant trade inhibitory effect on imports of U. S. timber. In the long term, China will increase its dependence on imports of American timber, especially of American log. The concentration of raw wood import market will increase. If the concentration of raw wood import market is too high, the timber exporters will implement the prohibition of logging and export restrictions, and China's raw wood import will be seriously affected. Therefore, China needs to adjust the source structure of log import and disperse the risk of log import. Although the concentration of sawn timber import market will decline, the risk of sawn timber import market is still large. In order to ensure the stable supply of timber resources in China and reduce trade risk, the diversification of import market should be realized. It is necessary to pay attention to measuring the export output elasticity of timber exporting countries, evaluating and tracking the supply security of major timber exporting countries, and reducing the import risks of log and sawn timber. Finally, we should strengthen foreign trade negotiations with timber exporters, establish good foreign trade relations, and promote the stability of the timber trade environment. [ABSTRACT FROM AUTHOR]

Using an imported timber-based solid wood box bed (2000 mm × 1800 mm) as the functional unit, the ILCD 2011 midpoint assessment method was used to measure the life cycle carbon emissions of the product. Using this assessment, the Dijkstra algorithm was adopted to determine the shortest supply chain path and to obtain the minimum carbon footprint of the supply chain. Results showed that the total carbon footprint of the wood bed was 464 kg for the control case. For experimental cases, the carbon footprint ranged from 456 kg to 517 kg CO2-eq. The upstream process was identified as the primary contributor to the carbon footprint, accounting for 74.6% to 80.7% of the total carbon footprint, followed by the downstream and the core-stream processes. Configuration of a timber harvesting system with lower fuel consumption, purchasing timber from areas within shorter transportation distance, and reducing the proportion of incineration for waste treatment were feasible solutions to reduce the carbon footprint of the product. A case study optimizing the low-carbon path for the wooden furniture supply chain determined the shortest path for the participants in each link, such that the minimum total carbon footprint of the supply chain was 463 kg CO2-eq. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) scanning of logs makes appearance-grading virtual sawn timber possible before the log is sawn. A CT-scanner can measure the knot structure inside a scanned log, inferring how to saw the log. The knot structure of virtual sawn timber was graded as being suitable or not for a specific product by the existing rule-based approach and used to create a set of descriptive statistical variables used by two machine learning models. The PLS models were trained on two quality references; the quality grade of the finished product or the image-grade based on images of the sawn timber, extracted from the dry-sorting station's automatic grading system and graded by two experienced researchers. The results show that the two PLS models perform equally well when sorting sawn timber to the customer, indicating that the quality references are equally useful for training a PLS model. The PLS models both delivered 93% of the dried sawn timber to the customer, leaving very little sawn timber with customer-specific properties at the sawmill, of which 89% and 90% of the delivered sawn timber passed the intended product's quality demands. The rule-based approach delivered 85% dried sawn timber with a 73% pass rate. [ABSTRACT FROM AUTHOR]

Knot detection is a challenging problem for the wood industry. Traditional methodologies depend heavily on the features selected manually and therefore were not always accurate due to the variety of knot appearances. This paper proposes an automated framework for addressing the aforementioned problem by using the state-of-the-art YOLO-v5 (the fifth version of You Only Look Once) detector. The features of surface knots were learned and extracted adaptively, and then the knot defects were identified accurately even though the knots vary in terms of color and texture. The proposed method was compared with YOLO-v3 SPP and Faster R-CNN on two datasets. Experimental results demonstrated that YOLO-v5 model achieved the best performance for detecting surface knot defects. F-Score on Dataset 1 was 91.7% and that of Dataset 2 was up to 97.7%. Moreover, YOLO-v5 has clear advantages in terms of training speed and the size of the weight file. These advantages made YOLO-v5 more suitable for the detection of surface knots on sawn timbers and potential for timber grading. [ABSTRACT FROM AUTHOR]

Sawmills are economically important in Mexico due to the generation of added value in forest species Mexico due to the transformation of round wood to sawn wood, the sawmill industry is located in all agro ecological regions and states. These units are source of employment for women and men in remote areas inhabited by the poor and extreme poverty population, the objective of the was to quantify the monetary value that the sawmill industry contributes to the forest economy, for which statistical data from INEGI was used and SEMARNAT, the first with valuable information and the second on production in m3r; a 25-years horizon was considered: 1995-2019, which was broken down into four six-year terms and the first year of the current administration to know, the behavior, trend and participation of the economic value of the sawmill in various macroeconomic aggregates. The methodology consisted of using current (market) values and constant (deflated) values, with the base year 2013 (according to INEGI and in thus make the data comparable, know trends and quantify their variations with the statistical function average annual growth rate (tmca). In real terms, the importance of the value in the Mexican economy of the sawmill industry during the period of analysis was very scarce since at the country level it represented on average of the 25 years considered, only 0.09% of the national GDP and at the sector level primary (agriculture, livestock, forestry, hunting and fishing) increased its share to 2.81% of primary GDP. [ABSTRACT FROM AUTHOR]

Illegal and unsustainable logging of forests have contributed to deforestation and a massive loss of biodiversity, and despite the efforts to regulate the trade of plants and combat the commercialization of illegal logging, the problem continues. DNA analysis of plant tissues is an effective method in species identification, and it is important to dedicate efforts to obtain and amplify DNA from dry wood or exposed to a sawmill process in which its origin is not clear. The aim of this research was to present a strategy to identify tree species from sawn timber and roundwood, based on the use of molecular identification tools. Wood samples of standing trees of Pinus pseudostrobus (PFCap1), round core samples (Ro) and plank wood (SaT) of Pinus pseudostrobus and Pinus devoniana were used. All the samples underwent a DNA extraction protocol, amplification, sequencing, and analysis in the NCBI database. The results showed an efficient extraction of the genetic material, revealing high purity ratios ​​for the three sample groups (PFCap1, Ro and SaT) and quantitative data of the amplified DNA. The information obtained through sequencing showed identities of up to 100% homology (NCBI database). We can conclude that the standardized method developed was successful using the trnL and trnLF primers, managing to isolate, amplify, and sequence the DNA from sawn timber and roundwood, and to identify the age of the tree and the time elapsed between the felling of the tree and the sampling, which are directly related to the success of this method. [ABSTRACT FROM AUTHOR]

Effect of sawn zone on the quality of lumber in the evaluation of selected pine wood defects. In the course of research on the sawn pine raw material with defined distribution of the defects, a variable level of change in the presence of knots was assessed. Initially, the experimental material was classified in terms of the general-purpose timber, and then the strength classes of wood for structural applications were assigned. The proportion of sound knots increased in case of wood obtained from the middle and top zones. In the case of butt-end logs, an increase in the share of the rotten knots having an average diameter of 2-4 cm was observed. The intensity of the defect's occurrence corresponded with the zone of origin along the large-sized roundwood length. [ABSTRACT FROM AUTHOR]

Using multivariate partial least squares regression (PLS) to perform visual quality grading of sawn timber requires a training set with known quality grades for the training of a grading model. This study evaluated the grading accuracy of an independent test set of sawn timber when changing the aspects of class-balance and class-overlap of the training set consisting of 251 planks. The study also compared two ways of expressing the reference-grade of the training set; by grading images picturing the planks, and by grading the product produced from the planks. Two grading models were trained using each reference-grade to establish a baseline for comparison. Both models achieved a 76% grading accuracy of the test set, indicating that both reference-grades can be used to train comparable models. To study the class-balance and class-overlap aspects of the training set, 25% of the training set was removed in two training scenarios. The models trained on class-balanced data indicated that class-imbalance of the training set was not a problem. The models trained on data with less class-overlap using the product-grade reference suffered a 4%-points grading accuracy loss due to the smaller training set, while the model trained using the image-grade reference retained its grading accuracy. [ABSTRACT FROM AUTHOR]

Over half of the large African mahogany plantation estate in northern Australia has reached the mid-point of the target rotation length of 20 to 25 years. As such, there is increasing interest in understanding the potential volume and grade qualities recovered from these young trees using different processing methods. The objective of this study was to compare the recovery rates and product grade quality for rotary veneer using spindleless lathe technology and sawn boards using traditional sawing techniques. Net veneer recovery ranged between 42% and 55% of log volume, with most veneers being limited to D-grade. Compression, surface roughness, and grain breakout were the most prominent defects limiting veneer grade. The sawn-dried-dressed recovery was low, with less than 20% of the log volume representing a potential saleable product. The small log diameter combined with defects including wane, heart shake, pith, and knots reduced the potential recovery. A high presence of sawn board distortion was observed that negatively impacted the efficiency of sawn timber processing along with product recovery. While low, the recovery of veneers and sawn timber from young African mahogany was like other young plantation grown hardwoods. [ABSTRACT FROM AUTHOR]

Rule-based automatic grading (RBAG) of sawn timber is a common type of sorting system used in sawmills, which is intricate to customise for specific customers. This study further develops an automatic grading method to grade sawn timber according to a customer's resulting product quality. A sawmill's automatic sorting system used cameras to scan the 308 planks included in the study. Each plank was split at a planing mill into three boards, each planed, milled, and manually graded as desirable or not. The plank grade was correlated by multivariate partial least squares regression to aggregated variables, created from the sorting system's measurements at the sawmill. Grading models were trained and tested independently using 5-fold cross-validation to evaluate the grading accuracy of the holistic-subjective automatic grading (HSAG), and compared with a re-substitution test. Results showed that using the HSAG method at the sawmill graded on average 74% of planks correctly, while 83% of desirable planks were correctly identified. Results implied that a sawmill sorting station could grade planks according to a customer's product quality grade with similar accuracy to HSAG conforming with manual grading of standardised sorting classes, even when the customer is processing the planks further. [ABSTRACT FROM AUTHOR]

Holistic-subjective automatic grading (HSAG) of sawn timber by an industrial customer's product outcome is possible through the use of multivariate partial least squares discriminant analysis (PLS-DA), shown by part one of this two-part study. This second part of the study aimed at testing the robustness to disturbances of such an HSAG system when grading Scots Pine sawn timber partially covered in dust. The set of 308 clean planks from part one of this study, and a set of 310 dusty planks, that by being stored inside a sawmill accumulated a layer of dust, were used. Cameras scanned each plank in a sawmill's automatic sorting system that detected selected feature variables. The planks were then split and processed at a planing mill, and the product grade was correlated to the measured feature variables by partial least squares regression. Prediction models were tested using 5-fold cross-validation in four tests and compared to the reference result of part one of this study. The tests showed that the product adapted HSAG could grade dusty planks with similar or lower grading accuracy compared to grading clean planks. In tests grading dusty planks, the disturbing effect of the dust was difficult to capture through training. [ABSTRACT FROM AUTHOR]

Wood is a natural and environmentally friendly construction material widely used in various fields of industrial and civil engineering. Timber drying process has an effect on the consumer properties of the final product and is basic in wood processing technology. Ultra high frequency range is the most effective in drying sawn timber with the use of electromagnetic energy. A process unit comprising discretely arranged magnetrons and a mechanism for rotation of sawn timber along the axis in the chamber is presented in the study. Magnetrons discretely and uniformly arranged ensure better distribution of heat on the sawn timber during rotation and reduces drying time. The engineering solution reduces drying time by 38.75% and increases the volume of dried timber by 27.3%. Variable drying mode control improves efficiency of the process by 8-10% depending on the timber species and initial moisture. Experimental dependences characterizing operational modes of the process unit are obtained. A mathematical model of sawn timber drying in the chamber with discretely arranged magnetrons and a mechanism to ensure rotation of sawn timber along the axis is developed. The mathematical model is made in the object-visual modelling MatLab package (Simulink). The model adequacy is confirmed experimentally, discrepancy between the experimental data and the data obtained from the mathematical modelling is no more than 3%. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the attributes of selected sawn timber species for door, flooring, and furniture manufacturing in Malaysia. Sawn timber attributes are important for value-added wood products manufacturing in terms of market opportunities and consumer preferences. A questionnaire was distributed to 30 value-added wood products manufacturers, in which there were 10 manufacturers in each category: door, flooring, and furniture. The study evaluated three aspects: the choice of sawn timber species for particular types of wood products, the source of origin of sawn timber, and the attributes that determined the choice of the sawn timber species for a particular product. The common local sawn timber species include rubberwood, meranti, merpauh, merbau, and kempas species, while poplar, oak, cherry, and pine represent imported species. It was found that cost, supply/availability, product specification, and market/buyer preferences were among the most important factors influencing the selection of sawn timber species for the manufacture of value-added wood products. However, these attributes were not statistically significant among the group of manufacturers and source of origin, respectively.

The effect of timber length on time-of-flight acoustic longitudinal measurements was investigated on the structural timber of four Spanish species: radiata pine (Pinus radiata D. Don), Scots pine (Pinus sylvestris L.), laricio pine (Pinus nigra Arn.), and maritime pine (Pinus pinaster Ait.). Time-of-flight longitudinal measurements were conducted on 120 specimens of dimensions 90 × 140 mm using three commercially available acoustic instruments (Sylvatest Duo, USLab, and Microsecond Timer). Time-of-flight data were initially obtained from the full-length (4 m) specimens, and then from the specimens cut to 3, 2, and 1 meter in length by successively cutting off 0.5 m from each end. The acoustic longitudinal velocity of the timber specimens of different lengths was also measured using a resonance-based acoustic method. The apparent acoustic longitudinal velocity for all species increased linearly as the timber length decreased from 4 to 1 meter. Acoustic velocity determined from time-of-flight data was significantly higher than the acoustic velocity determined using the resonance method, indicating systematic measurement errors associated with the time-of-flight instruments. Empirical models were developed for the relationships between time-of-flight measurements on timber specimens and timber lengths in the range of 1 to 4 m. Finally, a procedure was proposed to correct the time-of-flight data.

Density estimation by non-destructive or semi-destructive methods is applied mainly on softwood species. The instruments are expensive, the methods are complicated and the determination coefficients are low. In the present study, the simple core hollow drilling approach is revisited. Data of 600 cores or cylindrical specimens from 300 pieces of 10 different softwood and hardwood species were evaluated in the density range from 350 to 975 kg m−3. The data were obtained from complete pieces and from the cores from core drilling, while the difference between the two data sets is 1.7%. At higher densities, the differences are greater. A model was proposed concerning the piece density estimation with a determination coefficient of 0.98. It is concluded that core drill is a cheap and reliable method for density estimation and the data are equally reliable for radial (R) or tangential (T) probing. The cylindrical cores obtained are suitable for moisture content (MC) and species determination. [ABSTRACT FROM AUTHOR]

Three samples of sawn Radiata pine (Pinus radiata D. Don) timber, consisting of 150 pieces with dimensions of 80 mm x 120 mm x 2400 mm, 80 pieces with dimensions of 150 mm x 200 mm x 4500 mm, and 75 pieces with dimensions of 150 mm x 250 mm x 5600 mm, were visually graded according to the Spanish standard UNE 56544 (2011) to analyze the influence of visual grading requirements on both the grading yield and mechanical properties. The resulting percentages of the rejected pieces stood at 19 and 28% for 150 x 200 mm and 150 x 250 mm cross-section pieces, respectively. That percentage increased to 73% for 80 x 120 mm cross-section pieces. The grading yield and mechanical properties were then analyzed to determine the influence of warp defects. Three different criteria for limiting warp defects were considered, reducing the standard specifications. The modulus of elasticity, bending strength, and density were obtained. The results concluded that loosening specified requisites improves the visual grading output in the smallest cross-section, with no significant reduction in the mechanical properties. A proposal for a less rigorous specification of twist defects in the Spanish visual grading standard has been introduced.

Mitrovica is known as the region in which the first saws of timber were set there. Today this region supplies a very large part of Kosovo with sawn timber (coniferous). The trunks of coniferous species in this region are: pine, fir and spruce which mainly are imported from Montenegro. In this study, we tried to bring interesting data on the subjects of this region for sawing trunks and production efficiency of sawn timber, as well as field losses or form of waste, wood residue and sawdust. To conduct the study, there were taken a number of conifers, were sawn and measured to determine the efficiency of sawing trunks. Results of the study are provided below: The volume of sawing logs 23.071 m3 Boards 16.268 m3 Wood residue 3.941 m3 Sawdust 2.548 m3 Others 0.313 m3 The study shows that, by sawing trunks were produced 70.52% boards, 17.08% wood residue, 11.04% sawdust, and 1.36% others. If worked with better technical measures, by performing division of trunks according to diameters and by calculation of models by maximum sawing for each trunk diameter, sawing trunks efficiency would be higher. [ABSTRACT FROM AUTHOR]

The coniferous trees that are found in the Republic of Kosovo are mainly: pine, fir and spruce. Since the Republic of Kosovo does not have enough coniferous timber to fulfill the requirements, it is then forced to import such material from other countries. Importation is mainly done from Montenegro and Bosnia and Herzegovina. This study provides important information about sawmills involved in the sawing of trunks, the yield of the sawmill production, and how much the losses or wood residue like pieces, slats and sawdust will be. To accomplish the study, a number of coniferous trees were sawn into timber and appropriate measurements were made to determine the yield of cutting trunks. The results of the study without considering the add-on for drying are given below: The amount of sawn trunks was 18.158m3, sawn timber 13,710m3, wood residue, pieces and slats 2.626m3, sawdust 1.639m3, other 0.184m3. According to the study, it is seen that from cutting of trunks was produced 75.50% sawn timber, 14.46% wood residue, pieces and slats, 9.03% sawdust and 1.01% others. If worked with better technical measures by performing division of trunks according to diameters and by calculation of models by maximum sawing for each trunk diameter, sawing trunks yield would be higher. [ABSTRACT FROM AUTHOR]

The present paper reports the results of an investigation regarding the analysis of models for machine strength grading boards of resinous pine cultivated in the northeast of Argentina. An empirical research project with one sample containing 233 boards in structural sizes subjected to static bending and one sample enclosing 100 boards subjected to tension was carried out according to the European standards. One model based on a single parameter (modulus of elasticity) and another one based on a combined parameter (modulus of elasticity + density + knot ratio) were designed. Results showed that the efficiency of both models was higher than that of the visual method adopted by the standard IRAM. The high efficiency of both models was made evident by: i) the achievement of the characteristic values adopted by standards for the main properties; ii) an increase of the yield in the structural grades and, iii) a decrease of the spread results for modulus of elasticity within each strength class, which makes it possible to satisfy the variability requirements adopted by the national design rules. [ABSTRACT FROM AUTHOR]

The origin of the raw material is a key aspect for strength grading of timber. Large grading areas are favored by the sawmilling industry as they require less effort in handling and documentation during the production process. However, large growth areas can also cause problems, as too high mechanical properties can be declared or yields may become uneconomical. The presented study presents a method that should allow for timber from different countries to be combined into a single grading area. Additionally, the influence on the yield for guaranteeing timber properties for differently defined populations is analysed. In this process, a number of available calculation methods for characteristic values for modulus of rupture, modulus of elasticity, and density are considered as the determination method also influences the final yield. Non-destructive and destructive test data from 8487 spruce specimens from Europe tested in bending or tension are the basis for the presented study. Based on the grading results the presented method is able to simply identify countries that may be combined. The definition of pan-European grading areas seems problematic if characteristic timber properties need to be guaranteed separately for each individual country as it may result in a severe drop in yield. However, checking timber properties only for the European population is unsatisfying as calculated timber properties considerably vary depending on the origin. As for the calculation method, the preferred method itself seems to have less impact on bending class assignments then on tension class assignments. [ABSTRACT FROM PUBLISHER]

The objective of this study was to assess the attributes of selected sawn timber species for door, flooring, and furniture manufacturing in Malaysia. Sawn timber attributes are important for value-added wood products manufacturing in terms of market opportunities and consumer preferences. A questionnaire was distributed to 30 value-added wood products manufacturers, in which there were 10 manufacturers in each category: door, flooring, and furniture. The study evaluated three aspects: the choice of sawn timber species for particular types of wood products, the source of origin of sawn timber, and the attributes that determined the choice of the sawn timber species for a particular product. The common local sawn timber species include rubberwood, meranti, merpauh, merbau, and kempas species, while poplar, oak, cherry, and pine represent imported species. It was found that cost, supply/availability, product specification, and market/buyer preferences were among the most important factors influencing the selection of sawn timber species for the manufacture of value-added wood products. However, these attributes were not statistically significant among the group of manufacturers and source of origin, respectively. [ABSTRACT FROM AUTHOR]

The effect of timber length on time-of-flight acoustic longitudinal measurements was investigated on the structural timber of four Spanish species: radiata pine (Pinus radiata D. Don), Scots pine (Pinus sylvestris L.), laricio pine (Pinus nigra Arn.), and maritime pine (Pinus pinaster Ait.). Time-of-flight longitudinal measurements were conducted on 120 specimens of dimensions 90 × 140 mm using three commercially available acoustic instruments (Sylvatest Duo, USLab, and Microsecond Timer). Time-of-flight data were initially obtained from the full-length (4 m) specimens, and then from the specimens cut to 3, 2, and 1 meter in length by successively cutting off 0.5 m from each end. The acoustic longitudinal velocity of the timber specimens of different lengths was also measured using a resonance-based acoustic method. The apparent acoustic longitudinal velocity for all species increased linearly as the timber length decreased from 4 to 1 meter. Acoustic velocity determined from time-of-flight data was significantly higher than the acoustic velocity determined using the resonance method, indicating systematic measurement errors associated with the time-of-flight instruments. Empirical models were developed for the relationships between time-offlight measurements on timber specimens and timber lengths in the range of 1 to 4 m. Finally, a procedure was proposed to correct the timeof- flight data. [ABSTRACT FROM AUTHOR]

Strength graded boards of Norway spruce (Picea abies(L.) Karst.) are important products for many Scandinavian sawmills. If the bending strength of the produced boards can be predicted before sawing the logs, the raw material can be used more efficiently. In previous studies it is shown that the bending strength can be predicted to some extent using discrete X-ray scanning of logs. In this study, we have evaluated if it is possible to predict bending strength of Norway spruce boards with higher accuracy using computed tomography (CT) scanning of logs compared to a combination of discrete X-ray and 3D scanning. The method was to construct multivariate models of bending strength for three different board dimensions. Our results showed that CT scanning of logs produces better models of bending strength compared to a combination of discrete X-ray and 3D scanning. The main reason for this difference was the benefit of knowing the position of where the boards were cut from the logs and therefore detailed knot information could be used in the prediction models. Due to the small number of observations in this study, care should be taken when comparing the resulting prediction models to results from other studies. [ABSTRACT FROM PUBLISHER]

The paper presents the results from an experimental study on geographic and wood growth/maturation related variation in technical quality of centre-yield sawn timber of Norway spruce (Picea abies (L.) Karst) of three dimensions (38*100, 50*150, 63*200) after sawing, kiln drying (two steps) and ripping. The dimensions represented primary-processed materials for selected value-added further-processed products with special requirements for quality, including moisture content. Sawn timber quality was evaluated in three steps of saw-dry-rip process considering deformation and pith checking in individual pieces of sawn timber. The material consisted of 420 sawn pieces from three log regions in Finland (south-eastern, western, northern) and two log regions in north-western Russia (Republic of Karelia, Vologda). Significant differences in twist, bow and pith checking were shown in the different steps of processing between the geographic origins of the materials. Moderate increase in the deterioration was detected during the second drying phase. Ripping had even a positive effect regarding the occurrence of twist, bow and cup (not crook) and the apparent pith checking. Based on the results, recommendations were addressed on the technical suitability of logs and sawn timber to the selected value-added wood products, the geographic regions and processing steps in the focus. [ABSTRACT FROM AUTHOR]