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Russia is China's main log supplier and has implemented a series of log export control policies. The implementation of Russia's export control policy has inevitably had an impact on China's timber processing industry. This paper uses breakpoint regression to analyse the impact of the increase in the import price of logs under the Russian log export control policy on the market price of timber products in China. The results show that under the control policy, the increase in log import prices had a significant positive impact on the timber product market when April 2008, January 2010 and January 2019 were the breakpoints. Due to the lag effects in price transmission, the impact on China's timber product market was not reflected when July 2007 and January 2018 were the breakpoints. Based on the research conclusions, this paper puts forward some suggestions from the perspective of China's log supply security. [ABSTRACT FROM AUTHOR]

This study aims to investigate whether it is possible to predict the modulus of elasticity (MOE) and modulus of rupture (MOR) of lumber produced from different heights using the stress-wave velocity of standing trees or the dynamic Young's modulus of logs in Siberian larch (Larix sibirica). A total of 190 pieces of lumber (38 by 89 mm in cross section) were cut from 111 logs obtained from 25 standing trees. Significant positive correlation coefficients were found between the stress-wave velocity of standing trees and MOE (r = 0.776) and MOR (r = 0.702) of this lumber. The dynamic Young's modulus of the logs also correlated significantly with MOE (r = 0.745) and MOR (r = 0.584) values. The results obtained in the present study suggest that stress-wave velocity and dynamic Young's modulus are useful for selecting superior trees in tree breeding and sorting logs for producing structural lumber. [ABSTRACT FROM AUTHOR]

In this study, static bending measurements and online NIR spectra acquisitions were combined to construct modulus of elasticity (MOE) prediction model for sugi lumber. NIR spectra were acquired from tangential surface of sugi lumbers at a speed of 120 m min-1 to assess its effectiveness in the wood industry. Cross-validation partial least squares regression (CV-PLSR) and test-set-validation partial least squares regression (TSV-PLSR) analyses were employed for analysing the data. The second derivative (2d) spectra with 19 smoothing points (Savitzky- Golay algorithm, second polynomial) gave the best result as spectral pre-processing treatment with the lowest root mean square error of cross-validation and the highest coefficient of determination for cross-validation based on the optimum number of latent variables as assessed from the minimum validation residual variance value in the CV-PLSR analysis. These 2d spectra were then used in the TSV-PLSR analysis for 100 repetitions to check the robustness of the calibration. [ABSTRACT FROM AUTHOR]

Accurate detection of surface defects plays a vital role in automated analysis of lumber quality in the wood industries. A new method, based on a genetic optimisation of energy model, is introduced here for defect detection in lumber images. In this method, a hypothesis testing framework is defined, first to separate defects from natural tissue of lumber. Then, the boundary of lumber is estimated by a decision function based on the energy optimisation method which is driven by an irregular parametric genetic approach. Performance of the proposed algorithm was evaluated on real captured lumber images containing several types of surface defects. The results demonstrate that the proposed method extracts the defects approximately 4.4% better than its alternatives while at the same time decreasing false detections by approximately 5.4%. The results obtained also show considerable improvements in accuracy and precision of the proposed method compared to other examined methods, especially when a low false detection (i.e. at least 10%) is desired. [ABSTRACT FROM PUBLISHER]

In this study, the mechanical properties of laminated strand lumber and oriented strand lumber were investigated. Two species of fast growing; Poplar ( Populus deltoides) and Paulownia ( Paulownia fortunei) were used. Urea formaldehyde resin was used to manufacture these products and this resin was reinforced with four levels of nanoclay (0, 2·5, 5 and 7·5%) based on dry weight of resin. Press temperature, press time and press pressure were 120°C, 5 min and 11 kg cm−2 respectively. Statistical analysis showed that the effects of species and nanoclay on the panel properties were statistically significant at 95% confidence interval. Modulus of rupture, modulus of elasticity, internal bond, shear strength and screw holding strength were analysed in boards. It was found that if nanoclay content was increased to 5 or 7·5%, all properties were significantly improved, when Populus deltoides was compared to Paulownia fortunei, the poplar panel had excellent performance. [ABSTRACT FROM AUTHOR]

In this paper, are described a series of tests that have been undertaken to elucidate the effects of geometry, material properties and reinforcement location on the flexural properties of laminated veneer lumber. The fracture modes are found to be a function of the properties and location of the reinforcement and ultimately the strength of bonding between the components. The use of high modulus reinforcements is beneficial to enhancing the stiffness of laminated veneer lumber, whereas lower stiffness reinforcements are beneficial for the enhancement of strength. Lowered fractions of rod and plate reinforcement are as beneficial as higher fractions of rod and plate reinforcement in reinforcing timber, provided they are judiciously positioned in the timber and have a stable bond. [ABSTRACT FROM AUTHOR]