Spremembe fizikalnih lastnosti hrastovega lesa iz zgodovinskih konstrukcij v življenjski dobi

Aleš Straže (Author), Matjaž Dremelj (Author), Ervin Žveplan (Author), Katarina Čufar (Author)

Abstract

Raziskali 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 lesa.

Keywords

les;hrast;lesena gradnja;Quercus sp.;staranje;barva;dimenzijska stabilnost;sorpcija;

Data

Language:	Slovenian
Year of publishing:	2018
Typology:	1.01 - Original Scientific Article
Organization:	UL BF - Biotechnical Faculty
UDC:	630814.7:630812
COBISS:	2921609
ISSN:	0024-1067
Parent publication:	Les
Views:	689
Downloads:	165
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Changes in physical properties of oak wood from historical constructions during service life
Secondary abstract:	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 oak.
Secondary keywords:	oak;wood;ageing;colour;hygroscopicity;dimensional stability;sorption;
URN:	URN:NBN:SI
Type (COBISS):	Article
Pages:	str. 5-14
Volume:	ǂLetn. ǂ67
Issue:	ǂšt. ǂ1
Chronology:	2018
ID:	12852166