Physical and Mechanical Properties of Hornbeam Wood from Dominant and Suppressed Trees/Fizikalna i mehanicka svojstva drva graba dominantnih i potisnutih stabala

Physical and mechanical properties are important factors in determining the suitability and application of wood material. This study aimed to investigate physical and mechanical properties of hornbeam wood (Carpinus betulus L.) in dominant and suppressed trees. Disks and logs of wood were cut at breast height to examine physical properties (oven-dried density, basic density, longitudinal shrinkage, tangential shrinkage, radial shrinkage, and volumetric shrinkage) and mechanical properties (static bending, compression strength parallel to the grain, compression perpendicular to the grain and hardness). T-test analysis indicated that forest mass (dominant-suppressed trees) affected the mechanical properties significantly (except modulus of elasticity). No significant difference was found between dominant and suppressed trees in terms of physical properties. MOE and MOR are higher in suppressed trees than in dominant trees. The average values of compression strength parallel to the grain, compression strength perpendicular to the grain and hardness of hornbeam wood were higher in the dominant trees than in the suppressed stands. In terms of mechanical properties of hornbeam wood in suppressed and dominant trees, the quality of wood is fair. Keywords: suppressed trees, dominant trees, hornbeam, physical properties, mechanical properties Fizikalna i mehanicka svojstva vazni su cimbenici pri odrecivanju prikladnosti i primjene drvnog materijala. Ova je studija usmjerena na istrazivanje fizikalnih i mehanickih svojstava drva graba (Carpinus betulus L.) dominantnih i potisnutih stabala. Diskovi i uzorci drva izrezani su na prsnoj visini stabla kako bi se odredila fizikalna svojstva (gustoca apsolutno suhog drva, nominalna gustoca drva, uzduzno utezanje, tangencijalno utezanje te radijalno i volumno utezanje) i mehanicka svojstva (staticko savijanje, tlacna cvrstoca paralelno s vlakancima, tlacna cvrstoca okomito na vlakanca i tvrdoca). Analiza statistickim T-testom pokazala je da je sumska biomasa dominantnih i potisnutih stabala znacajno utjecala na mehanicka svojstva drva graba (osim na modul elasticnosti). Mecutim, nije zabiljezena znacajna razlika u fizikalnim svojstvima drva dominantnih i potisnutih stabala. Dobivene vrijednosti MOE i MOR za drvo potisnutih stabala vece su od vrijednosti dobivenih za drvo dominantnih stabala. Prosjecne vrijednosti tlacne cvrstoce paralelno s vlakancima, tlacne cvrstoce okomito na vlakanca i tvrdoce grabova drva dominantnih st