Variations of the hardness of Balkan beech wood (Fagus moesiaca cz.)

Abstract

The aim of this research is to determine the significance of the impact of the origin of wood trees (generative or vegetative), height of the cross-section (1,3 and 5,3 m above ground) and relative age of annual rings (distance from pith in radial direction) in which the measurements are made, on the variation of wood hardness, at near same ecological factors. For determination of wood hardness Brinell method is used, and for statistical processing of the data from the measurements, software package SPSS Statistics 21 is used. On the basis of the obtained values form the tests for normal distribution of the hardness and analysis of the homogeneity of the variance, as well as on the basis of multiple comparison for determination of statistical significant differences between average values of wood hardness from different tree trunks, cross-section and age, it is found that the trees from vegetative origin produce wood with significantly higher hardness compare to the trees form generative origin. Among the two cases, the wood hardness of section 1,3 m is significantly higher than the wood hardness of section 5,3 mm. The increment of the relative age of annual rings in trees from vegetative origin in certain interval is followed by increment in wood hardness, whereupon the wood hardness decreases, while in trees from generative origin, first in certain interval the hardness is decreased, whereupon it is increased. The obtained results of these researches, supplemented with the comparative researches of processing of standard (from generative origin) and nonstandard (from vegetative origin) timber should be taken in consideration when choosing the technological process.