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Selected properties of kauri wood (Agathis australis (D. Don) Salisb.)

Czajka M., Fabisiak E., Turkowiak N.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2018

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No. 103

90--96

EN

The article presents results of the study of kauri wood which it was underground for 45,000 years and excavated in the form of logs from peat bogs located in the northern parts of New Zealand. Kauri wood is a raw material highly valued by the manufacturers of stringed musical instruments, not only because of its acoustic properties, but also because of the unique pattern of wood. The following wood properties were determined: widths of annual rings, the share of late wood, lengths of early and late wood tracheids, dimensions of wood rays and the density of their occurrence on the tangent section, as well as wood density and sound propagation velocity. The studied wood was characterised by narrow annual rings and a very low share of late wood zones (less than 15%). The weighted mean lengths of the tracheids in individual annual rings fell within a narrow range from 3600 m to 3900 m. All wood rays were uniseriate, and there were 20 rays per 1 mm2 of the tangent section. The wood density was 460 kg/m3, the mean velocity of sound propagation in longitudinal direction was 3700 m/s.

PL

Badania przeprowadzono na drewnie soplicy australijskiej, które znajdowało się w torfowych mokradłach w północnych rejonach Nowej Zelandii przez 45000 lat. Drewno to jest bardzo cennym surowcem dla producentów strunowych instrumentów muzycznych, nie tylko ze względu na jego właściwości akustyczne, ale także niepowtarzalny rysunek. W pracy oznaczono podstawowe parametry makrostrukturalne oraz cechy budowy anatomicznej takie jak długości cewek drewna wczesnego i późnego oraz wymiary i gęstość występowania promieni drzewnych. Oznaczono także gęstość drewna i prędkość propagacji dźwięku. Wykazano, że drewno to odznaczało się wąskimi przyrostami rocznymi i bardzo małym udziałem drewna późnego, nieprzekraczającym 15%. Obliczone średnie ważone długości cewek zawierały się w wąskim przedziale od 3600 um do 3900 um. Gatunek ten posiada tylko jednorzędowe promienie drzewne, a na 1 mm2 przekroju stycznego jest ich 20. Średnia prędkość propagacji dźwięku w kierunku podłużnym kształtowała się na poziomie 3700 m/s, a w promieniowym 2140 m/s.

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Investigation of Modal Behaviour of Resonance Spruce Wood Samples (Picea abies L.)

Mania P., Fabisiak E., Skrodzka E.

Archives of Acoustics

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2017

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Vol. 42, No. 1

23--28

EN

Results of experimental modal analysis of a resonance and non-resonance spruce wood (Picea abies L.) are presented. The resonance wood came from a tree from Poland and Bosnia and Herzegovina, while the non-resonance wood came from the vicinity of Olsztyn from the north-eastern Poland. The modal parameters (modal frequency, modal damping and mode shapes) of the wood samples were determined for the samples of 8 mm in thickness. Modal analysis was made by pulse excitation. The resonance and non-resonance wood differ in the fundamental modal parameters as well as in the number of potential modes. Additionally, calculated values of damping factor are presented. The values are much bigger for a non-resonance wood than for good quality resonance spruce.

3

Radial variation of macrostructural parameters and density of wood in dominant trees of coniferous species

Czajka M., Fabisiak E.

Drewno : prace naukowe, doniesienia, komunikaty

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2016

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vol. 59, nr 197

179--187

EN

This paper presents the results of measurements of wood macrostructure parameters and wood density in dominant trees of Scots pine, Norway spruce, and European larch, originating from an even-aged stand, therefore growing on identical sites and in identical climatic conditions. The influence of the cambial age of annual rings and the cross-section area on the measured features was determined in this study. The measurements of macrostructural parameters were taken using an image analyser. Basic density was determined on samples containing three annual rings. In the analysed species the widths of annual rings demonstrated significant differences in the first 50 years of tree growth. The smallest widths of annual rings throughout the whole period of tree growth were observed in the case of spruce wood. The latewood share, analysed within 25-year increment zones, demonstrated statistically significant differentiation between tested species in all selected zones of the cross-section. For each of the tested species the lowest shares were observed for juvenile wood. The lowest density values were observed, therefore, in this zone. In the mature wood of larch and pine an approximate 20% increase in the density was observed and furthermore, all the way to the circumference, density showed slight fluctuations. In the case of spruce wood, the values of density within the analysed zone increased towards the circumference. Accordingly, larch wood and pine wood were characterised by greater uniformity of properties, compared to spruce wood. This observation has important practical implications, because density is a determinant of many properties that influence the technical quality of wood.

4

The influence of the trunk cross section zone on the emission of VOC, chemical composition and structural parameters of fir (Abies alba Mill.)

Czajka M., Fabisiak E.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2014

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No. 87

45--50

EN

The level of volatile organic compounds emission from the heartwood zone and the sapwood zone of fir was determined. Tests were carried out by the chamber method based on the requirements of ISO 16000 standards. The samples of air from the chamber were taken after 3, 7, 14 and 28 days. The content of particular chemical components in the both parts of the trunk cross section was determined as well. It was determined that the sample of heartwood originated from the typical juvenile wood zone and the sapwood sample from the mature wood zone. The border between these zones was defined based on the changeability of the tracheid length. Throughout the whole testing period the heartwood sample emitted more volatile organic compounds compared to the sapwood sample; however, the volumes of these emissions were the lowest compared to other previously studied softwood species.