VARIATION IN MECHANICAL PROPERTIES OF BEECH (FAGUS ORIENTALIS LIPSKY) WOOD GROWN ON SANGDEH FORESTS (MAZANDERAN), IRAN

Beech (Fagus orientalis Lipsky L.) is one of the most important broadleaf species in the Caspian Forests of Iran. The wood of Beech is highly appreciated in domestic wood industries especially furniture industry. In this study which is a part of the extensive surveying project of the main wood engineering properties of Iranian woods, the natural variations of strength and related properties of three trees of about 75 years old from Sangdeh Forests in Mazandran province were investigated.The properties were determined from tests on small clear specimens in the green and dry conditions following the ASTM Standard. The mechanical and physical properties studied include: stress at elastic limits, modulus of rupture, modulus of elasticity and modulus of elasticity in static bending; shear parallel to grain, maximum crushing strength, fiber stress at proportional limit and modulus of elasticity in compression parallel to grain; compression perpendicular to grain and specific gravity.The results of statistical analysis showed that the mechanical strength of the wood was found to be affected by percentage of moisture conten of wood specimens, height of sample tree and to some extend by geographical; direction