Vertical variation of density, flexural strength and stiffness of Persian silk wood

Vertical variation of density, flexural strength and stiffness of Persian silk wood The aim of this research was to investigate the effects of longitudinal position (stem height) and heart-sapwood on density, modulus of elasticity ( MOE ) and modulus of rupture ( MOR ) in bending for Persian silk wood ( Albizzia julibrissin) . Five normal trees were selected from the Guilan region, Iran. Samples for testing were prepared at four stem height levels (5%, 25%, 50% and 75% of total stem height) in both positions along radial direction (heartwood and sapwood). Analysis of variance results (Anova) indicated that the effects of longitudinal position (stem height) and heartwood-sapwood on the wood density, MOE and MOR were significant. The mean of wood density, MOE and MOR along longitudinal position from base to top decreased with height. The mean of wood density, MOR and MOE in sapwood are lower compared to the corresponding values for heartwood. The relationship between wood density and mechanical strength properties were analyzed by regression models. A positive correlation was found between wood density with MOE and MOR in both heartwood and sapwood.

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