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A study on veneer recovery ratio and value of eucalypt clones
- REN Shi-qi, LUO Jian-zhong, PENG Yan, XIE Yao-jian,
LU Wan-hong, CAO Jia-guang, JIANG Ying
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2010, 19(6):
46-54.
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The veneer recovery ratio and value of eleven 6-year-old eucalypt clones were investigated using Pilodyn and Fakopp to estimate the density of outside wood and acoustic wave velocity as a non-destructive testing tool. The CIRAD-Forest method was used to measure wood growth stress and the results were combined with measurements of log external characters and veneer quality grade to find the major significant factors influencing veneer recovery ratio and value using ANOVA, correlation analysis, and multiple linear regression analysis. There were significant differences in wood density, acoustic wave velocity, growth strain, min-sed, sweep and end splitting between different clones. Knots, especially dead knots, including holes and splitting, were major factors reducing veneer quality grade. There were significant differences between veneer recovery ratio and quality grade. Veneer recovery ratio (%) of clones ranked from high to low was GL9(48.27), EC34(47.17), LH1(44.00), DH32-22(42.00), GL4(37.56), SH7(34.88), UC184-1(34.38), LH5(31.06), M1(29.74), DH201-2(25.41), and SG1(16.28). The highest recovery ratio was 2.97 times that of the lowest. The single log value (RMB/log) of clones ranked from high to low was C34(13.37), GL9(13.12), GL4(12.36), LH1(12.02), DH32-22(11.55), LH5(10.72), SH7(9.22), UC184-1(7.95), M1(7.55), DH201-2(5.97), and SG1(4.88), and the highest value was 2.74 times that of the lowest. The unit volume value (RMB/m3) of clones ranked from high to low was C34(856.49), LH1(794.55), GL9(788.68), DH32-22(763.02), GL4(681.44), SH7(629.35), UC184-1(597.66), LH5(559.08), M1(538.39), DH201-2(450.49), and SG1(294.53), and the highest value was 2.91 times that of the lowest. E. urophylla×E. grandis as plywood lumber showed higher value than the other four variants during this trial. Sweep was the major factor to influence veneer recovery ratio and value, while wood density, small end diameter, acoustic wave velocity and end split index had significant impacts on veneer recovery ratio and value. Pilodyn and Fakopp were able to approximately predict and estimate veneer recovery ratio and unit volume value.