Abstract

 

 

Accepted 17th May, 2014

 

The main objective of the study was to investigate the physical and mechanical properties of Pinus patula. For this study, 28 years old pinus patula stand was used along the tree height from three portions, namely bottom, middle, top. Six trees were harvested and lumber used for testing were produced in Arsi Forest Enterprise mobile sawmill. A total of 336 samples free from visible defects were produced from three log positions of Pinus patula, each for modulus of elasticity, modulus of rupture, compression parallel to the grain, and impacts bending of dry and green and 84 samples of shrinkage were tested. For this experiment, variable of physical properties like basic density, initial moisture content and shrinkage were evaluated. The result showed that tree height had significant (p<0.05) effects on basic density and insignificant effects on initial moisture content and tangential and radial shrinkage. Basic density, initial moisture content and radial shrinkage shows decreasing trend from bottom to top log, but tangential shrinkage increase from bottom to top log. Similarly, the result indicated that highly significant (p<0.01) in all mechanical properties except specific impact resistance of green sample. The result of specific impact resistance of green sample was significant (p<0.05). The value of mechanical properties decreases from bottom to top log in all tests of green and dry samples. Generally, tree positions influence the physical and mechanical properties of wood.  

 

Keywords: Density, compression; elasticity; moistures; resistance