Donetsk, Russian Federation
This paper presents and analyzes the dependence of elasticity modulus (E) in pedunculate oak ( Quercus robur L.) and red oak ( Quercus rubra L.) from seasonal variations. Temperature range of E variation in the samples was -15°C -+35°C at the humidity of 65 to 45%. We used the following indices to assess mechanical resistance: RRB - relative resistance to bending, Pcr and mcr - critical permissible pressure and weight, Hcr - critical stem height. Our data testify that variations of elasticity modulus within the cycle of freezing - thawing are most of all affecting resistance of the trees with minimum correlation of the stem diameter to its height. Thus, as far as the investigated plant groups are concerned, Quercus robur L. and Quercus rubra L. undergrowth over 2 meters high and the thinnest suppressed adult trees are vulnerable to the risks of deformation and breaks under their own weight during temperature variations.
Quercus robur L, Quercus rubra L, mechanical stability, modulus of elasticity, Quercus robur L, Quercus rubra L
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