Determination of the modulus of elasticity of juvenile and mature wood of Pinus taeda L.with ultrasonic method

Pinus sp. wood has an increasing importance on supplying brazilian wood industry. The diminution of adult and large diameter trees supply deriving from natural tropical forests, became usual the production of wood on short rotation plantation, with considerable proportion of juvenil wood. Results from several researches have been demonstrated that MOE and mechanical strength are strongly affected by juvenile wood occurrence. This research was developed with the main objective of correlating dynamic modulus of elasticity (non-destructive ultrasound tests) and MOE. Six trees of Pinus taeda, 34 years old from the controlled plantations of the Estação Experimental de Itapeva - SP, Brazil, were randomly chosen for the experimental program. Each tree resulted on four logs (3.75 m long), and from each log the central board was used (80 mm thick). Boards were dried to 12% moisture content and from them longitudinal specimens (4 cm x 4 cm x 45 cm) were sawed. All specimens were submitted to non-destructive tests (ultrasonic method) and destructive conventional compression tests. Results had shown good sensitivity of the method of the ultrasound (R² <FONT FACE=Symbol>»</FONT> 0,90) on evaluating MOE of juvenile and mature wood.

ultrasonic method; Pinus taeda L.; juvenile wood


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