Yield and mechanical properties of veneer from Brachystegia nigerica |
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| Authors: | Babatola Olufemi |
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| Institution: | 1. Department of Forestry and Wood Technology, Federal University of Technology, P. M. B. 704, Akure, Nigeria
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| Abstract: | In an effort to find suitable wood from natural forest to meet the demand for veneer products, the yield and tensile strength
of veneers produced from Brachystegia nigerica were investigated. Two trees of B. nigerica were separately selected from 10 different natural forest zones while two logs were obtained from each tree. The logs were
debarked and steamed in a vat prior to rotary peeling and slicing for veneer production. The optimum steam temperature was
determined by considering different temperatures: 50°C, 60°C, 70°C, 80°C and 90°C for 24 h. Thereafter, optimum steam time
was determined at the optimum temperature by considering durations of 24, 48, 72 and 96 h. The average taper of 0.75 mm per
1.0 m length was recorded for B. nigerica, indicating that the logs were reasonably cylindrical; thereby its logs are good for the production of veneer. The yield
ranged from 44% to 61% with an average of 52% of the log input. The tensile strength of the veneer was tested perpendicular
to grain and both peeled and sliced veneers had the highest tensile strength between 70C and 90C, suggesting that softening
of wood polymers, especially lignin, is between 70°C and 90°C. The optimum temperature and time for veneer production are
70°C and 48 h, respectively. Commercial production of veneer from B. nigerica is feasible based on the yield and mechanical properties of the obtained veneer, thereby encouraging the expansion of the
scope of its utilization. |
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| Keywords: | veneer Brachystegia nigerica yield tensile strength optimum steam temperature optimum steam time |
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