Abstract
The aim of the present investigation was the identification of changes in the density of oak (Quercus robur L.) due to the influence of thermal modification. The reduction of the density was recorded by High-Frequency Densitometry and compared to measurements based on the gravimetric method. To identify changes in density, the initial density and the density after thermal treatment were determined using the same sample. In conclusion, results from the High-Frequency Densitometry Method show smaller deviations than those from gravimetric method. In addition, High-Frequency Densitometry provides reasonably good results with respect to the localisation of changes in density within an annual ring. As expected, in contrast to the Gravimetric Method the High-Frequency Densitometry Method were proved to be applicable to localise the change of the tree-ring density. It can be summarized that the measurement of the local density change can be realized by High-Frequency Densitometry. The density of earlywood was significantly more reduced due to thermal modification than the density of latewood.
Zusammenfassung
Ziel der vorliegenden Untersuchungen war die Ermittlung der Dichteänderung von Eiche (Quercus robur L.) infolge einer thermischen Modifikation. Die Verringerung der Dichte wurde mittels Hochfrequenz-Densitometrie-Methode aufgezeichnet und mit den Messungen des Gravimetrischen Verfahrens verglichen. Um einen Vergleich der anfänglichen Dichte und der Dichte infolge der thermischen Behandlung zu ermöglichen, wurde die Untersuchung an denselben Proben vor und nach der Vergütung durchgeführt. Die Auswertung lässt den Schluss zu, dass die Hochfrequenz-Densitometrie-Methode weniger Abweichungen in ihren Ergebnissen zeigt, als die Gravimetrische Methode. Die Hochfrequenz-Densitometrie-Methode erwies sich im Gegensatz zu der Gravimetrischen Methode als anwendbar, um die Änderung der Dichte innerhalb eines Jahrringes zu lokalisieren. Es kann zusammengefasst werden, dass die Messung der lokalen Dichteänderung durch Hochfrequenz-Densitometrie-Messungen möglich ist und dass sich die Dichte des Frühholzes durch die thermische Modifikation signifikant stärker gegenüber der des Spätholzes verringert.
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Acknowledgments
This research has been conducted in cooperation between the Eberswalde University for Sustainable Development and Ukrainian National Forestry University with the support of the German side. The authors would like to thank Prof. Dr. Martin Guericke for providing the HFD equipment, Christian Müller for his assistance in conducting experiments and preparing the experimental samples as well as Nadine Herold and Fabian Wulf for active participation in the discussion of the results.
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Shchupakivskyy, R., Clauder, L., Linke, N. et al. Application of high-frequency densitometry to detect changes in early- and latewood density of oak (Quercus robur L.) due to thermal modification. Eur. J. Wood Prod. 72, 5–10 (2014). https://doi.org/10.1007/s00107-013-0744-x
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DOI: https://doi.org/10.1007/s00107-013-0744-x