The present study aims at investigating the variation in average ring width, physical properties (oven-dry density, basic density, volumetric shrinkage, maximum moisture content, percentage of cell wall, percentage of porosity) and mechanical strength (modulus of rupture, modulus of elasticity and compression parallel to the grain) of eldar pine tree wood (Pinus eldarica Medw.), cultivated in the north of Iran (Marzanabad site). To carry out the measurements, the test specimens were prepared from three stands and 3 logs at breast height, based on ASTM–D143 standard. The testing samples were cut along radial axis, from pith to bark, to determine annual ring width and physical properties, mature wood being used to measure mechanical strength characteristics. The results showed that oven-dry density, basic density, volumetric shrinkage and percentage of cell wall increased along radial direction from pith to bark, while ring width, maximum moisture content and porosity decreased. The average density at 12% moisture content was of 578.35 kg m-3, the modulus of rupture (MOR) – of 73.77 MPa, modulus of elasticity (MOE) – of 6.73 GPa, and compression parallel to the grain – 43.82 MPa. The relationships between ring width and wood density, and between density at 12% moisture content and mechanical strength properties were determined by regression analyses. Positive relationships were found between density at 12% moisture content and mechanical strength properties, while the annual ring width showed a negative correlation with wood density. Overall, eldar pine trees growing in this site have low wood quality, according to the static quality and reference p value (ratio of static bending strength and compression strength parallel to the grain).
کلید واژگان :Pinus eldarica, ring width, physical properties, mechanical characteristics
ارزش ریالی : 600000 ریال
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