751 KB35 KB199820242018Čufar, KatarinaDremelj, MatjažStraže, AlešŽveplan, Ervinštevilka:1letnik:67str. 5-14ISSN:0024-1067ISSN:2590-9932COBISSID_HOST:2921609URN:URN:NBN:SI:doc-L76FJ98IslBiotehniška fakulteta, Oddelek za lesarstvoLes (Ljubljana)ageingbarvacolourCroatian Growthdimensional stabilitydimenzijska stabilnosthrasthygroscopicityleslesena gradnjaoakQuercus sp.sorpcijasorptionstaranjewoodSpremembe fizikalnih lastnosti hrastovega lesa iz zgodovinskih konstrukcij v življenjski dobi| Changes in physical properties of oak wood from historical constructions during service life|We examined the physical properties of oak wood (Quercus sp.) felled four to 512 years ago, grouped in age groups of 100-600 years. The wood originated from recently felled trees and from historical constructions in Slovenia. The selected wood was dendrochronologically dated. We made standardized samples and determined wood density, colour, dimensional stability and sorption properties. Visual and CIELab analyses showed that the colour of the heartwood became darker with age. Historical oak wood was characterised by lower hygroscopicity and higher dimensional stability, especially in the tangential direction, as well as reduced transverse shrinkage anisotropy compared to recently felled wood. The density of oak wood did not change with age, it was dependent on tree-ring widths and the proportion of latewood, and increased along with the proportion of latewood. Besides ageing, the location of wood during its service life and exposure to climate fluctuations also seemed to influence the dimensional stability and hygroscopicity of historical oakRaziskali smo fizikalne lastnosti hrastovega lesa (Quercus sp.), pri katerem je od poseka minilo od 4 do 512 let in smo ga razdelili v stoletne starostne skupine 100-600. Mlajši les smo pridobili ob poseku dreves, starejši les pa iz zgodovinskih konstrukcij v Sloveniji. Izbrani les smo najprej dendrokronološko datirali, izdelali normirane vzorce za analize ter določili gostoto, barvo, dimenzijsko stabilnost in sorpcijske lastnosti. Vizualno in v CIELab barvnem prostoru smo ugotovili, da je barva jedrovine s starostjo postala temnejša. Pri starem hrastovem lesu smo ugotovili tudi manjšo higroskopnost in izboljšano dimenzijsko stabilnost, zlasti v tangencialni smeri, ter manjšo prečno krčitveno anizotropijo.Gostota hrastovega lesa se s staranjem ni spremenila, odvisna pa je bila od širine branik (naraščala je z večanjem deleža kasnega lesa). Rezultati nakazujejo, da na dimenzijsko stabilnost in higroskopnost poleg procesov staranja ver-jetno vpliva tudi mesto vgradnje in klimatska nihanja tekom uporabe lesaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaZveza lesarjev Slovenije