Warsaw University of Life Sciences

Annals Warsaw University of Life Sciences

Forestry and Wood Technology No 107 Warsaw 2019 Contents:

PAWEŁ KOZAKIEWICZ, ROBERT BRZOZOWSKI, AGNIESZKA LASKOWSKA, MARCIN ZBIEĆ „Acoustic insulation properties of selected African wood species: padouk, bubinga, sapele.” 4

PIOTR F. BOROWSKI „Bamboo as an innovative material for many branches of world industry.” 13

MARTA BABICKA, KRZYSZTOF DWIECKI, IZABELA RATAJCZAK „A comparison of methods for obtaining nanocellulose using acid and ionic liquid hydrolysis reactions.” 19 SŁAWOMIR KRZOSEK, IZABELA BURAWSKA-KUPNIEWSKA, PIOTR MAŃKOWSKI, MAREK GRZEŚKIEWICZ „Comparison results of visual and machine strength grading of Scots pine sawn timber from the Silesian Forestry Region in Poland.” 24

ZUZANA VIDHOLDOVÁ, DOMINIKA KORMÚTHOVÁ, JÁN IŽDINSKÝ, RASTISLAV LAGAŇA „Compressive resistance of the mycelium composite.” 31

KATARZYNA MYDLARZ „Corporate social responsibility in woodworking enterprises.” 37

BEATA FABISIAK, ANNA JANKOWSKA, ROBERT KŁOS „Dual study possibilities in selected EU countries.” 45

IZABELA BETLEJ, BOGUSŁAW ANDRES „Evaluation of fungicidal properties of post-cultured liquid medium from the Dual culture of Kombucha microorganisms against selected mold fungi.” 54

IGOR NOVÁK, JURAJ PAVLINEC, IVAN CHODÁ, ANGELA KLEINOVÁ, JOZEF PREŤO, VLADIMÍR VANKO „The grafting of metallocene copolymer to higher polarity with acrylic acid.” 60

JOANNA WACHOWICZ, KLAUDIA WIERZBICKA, PAWEŁ CZARNIAK, JACEK WILKOWSKI „The influence of WC grain size on the durability of WCCo cutting edges in the machining of wood-based materials.” 65

MAREK WIERUSZEWSKI, RADOSŁAW MIRSKI, ADRIAN TROCIŃSKI, JAKUB KAWALERCZYK „Influence of qualitative and dimensional classification of Pinewood raw material as an efficiency indicator in the production of selected timber assortments.” 72

SZYMON NIECIĄG, TOMASZ ROGOZIŃSKI, JACEK WILKOWSKI, BARTOSZ PAŁUBICKI „Timber cross-cutting accuracy obtained with an automatic saw.” 80

MARTA DWORNIK, ANNA ROZANSKA, PIOTR BEER „Traditional ornaments of Świdermajers’ style windows in the town of Otwock.” 84

DARIA BRĘCZEWSKA-KULESZA, GRZEGORZ WIELOCH „Use of wood in the Baltic courses architecture on the example of Binz in Ruges.” 104

JOZEF KÚDELA „Wood fibreboard paraffin hydrophobization and the impact of this treatment on the board surface finishing quality.” 115

MAREK WIERUSZEWSKI, RADOSŁAW MIRSKI, ADRIAN TROCIŃSKI „Raw material factors affecting the quota of structural wood in sawmill production.” 124

DONATA KRUTUL, ANDRZEJ ANTCZAK, ANDRZEJ RADOMSKI, MICHAŁ DROŻDŻEK, TERESA KŁOSIŃSKA, JANUSZ ZAWADZKI „The chemical composition of poplar wood in relation to the species and the age of trees.”131

EWA DOBROWOLSKA, DANIEL KUPIEC, ZBIGNIEW KARWAT „Testing the tightness of a square joint between oak wood elements.” 139

ADAM KRAJEWSKI, PIOTR WITOMSKI, ANNA OLEKSIEWICZ „The borings of Teredinidae in fossil wood of Taxodium Distichum Gothan, 1906.” 149

Scientific council:

Miroslav Rousek (Czech Republic) Ján Sedliačik (Slovakia) Nencho Deliiski (Bulgaria) Ladislav Dzurenda (Slovakia) Olena Pinchewska (Ukraine) Włodzimierz Prądzyński (Poland) Loredana Badescu (Romania) Kazimierz Orłowski (Poland) Iskandar Alimov (Uzbekistan)

Board of reviewers:

Bogusław Andres Teresa Kłosińska Andrzej Antczak Grzegorz Kowaluk Bogusław Andres Paweł Kozakiewicz Piotr Beer Adam Krajewski Izabela Betlej Krzysztof Krajewski Justyna Biernacka Sławomir Krzosek Piotr Boruszewski Agnieszka Laskowska Piotr Borysiuk Mariusz Mamiński Izabela Burawska-Kupniewska Mateusz Niedbała Ewa Dobrowolska Piotr Przybysz Michał Drożdżek Anna Różańska Jarosław Górski Jacek Wilkowski Emila Grzegorzewska Piotr Witomski Agnieszka Jankowska Marcin Zbieć

Errata: The authors of the article: Broda M., Mazela B., Królikowska-Pataraja K., Siuda J. (2015): The state of degradation of waterlogged wood from different environments. Annals of Warsaw University of Life Sciences - SGGW, Forestry and Wood Technology 91, pp. 23-27, explain, that: - at Table 1 a citation of the publication: Zborowska M., Królikowska-Pataraja K., Waliszewska B., Tekień P., Gajewska J., Kisiel I (2012): Condition of preservation and causes of degradation of bridge remains recovered from the bottom of Gągnowskie lake. Physico-chemical analysis of lignocellulosic materials. Part II (ed. by J. Zawadzki, B. Waliszewska) WULS-SGGW Press, Warszawa 2012, pp. 64-73 is missing, - at Table 2 a citation of the publication: Zborowska M., Królikowska-Pataraja K., Waliszewska B., Tekień P., Gajewska J., Kisiel I (2012): Condition of preservation and causes of degradation of bridge remains recovered from the bottom of Gągnowskie lake. Physico-chemical analysis of lignocellulosic materials. Part II (ed. by J. Zawadzki, B. Waliszewska) WULS-SGGW Press, Warszawa 2012, pp. 64-73 is missing. The missing citations were not a result of an intentional act of the authors but of an unfortunate oversight, and the present errata intends to remedy this omission.

Warsaw University of Life Sciences Press e-mail:[email protected]

SERIES EDITOR Ewa Dobrowolska ISSN 1898-5912 Anna Sekrecka-Belniak Mateusz Niedbała Drukarnia POZKAL Spółka z o.o. Spółka komandytowa 88-100 Inowrocław, ul. Cegielna 10 – 12

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 4-12 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Acoustic insulation properties of selected African wood species: padouk, bubinga, sapele

PAWEŁ KOZAKIEWICZ1, ROBERT BRZOZOWSKI1, AGNIESZKA LASKOWSKA 1, MARCIN ZBIEĆ2

1Department of Wood Science and Wood Preservation; 2Department of Technology and Entrepreneurship in Wood Industry, Faculty of Wood Technology, Warsaw University of Life Sciences - SGGW, 166 Nowoursynowska St., 02 - 787 Warsaw

Abstract: Acoustic insulation properties of selected African wood species: padouk, bubinga, sapele. The work determines the sound insulation properties of three wood species used in various types of acoustic partitions. The tests were carried out in a small acoustic chamber after generating white acoustic noise for 5.5 s. The level of sound intensity generated by the loudspeaker was 110 dB. The thickness of the wooden partitions was 20, 10 or 5 mm. The study was preceded by the determination of the moisture content, density and dynamic modulus of elasticity of the tested wood samples. In the 20–600 Hz frequency range, the sound insulation characteristics of the tested partitions changed dynamically but very similarly, while maintaining the mass law. In the higher frequency range, the impact of the partition thickness on insulation was individual, different for each wood species.

Keywords: African wood, acoustic insulation, density, dynamic modulus of elasticity, small acoustic chamber

INTRODUCTION Acoustic properties of wood determine its use, among other things, for the production of sound absorbing materials. With the application of wood in various types of partitions, e.g. wall elements (facades, cladding, panelling) and flooring, the sound insulation is taken into account [Kozakiewicz et al. 2012]. Isolation, i.e. attenuation, is the ability to weaken the intensity (silencing) of sounds passing through the material, expressed in decibels. Waves with higher frequencies (high tones) are much easier to suppress than those with low frequencies. The acoustic properties of wood are significantly affected by its density and modulus of elasticity. In a simplified manner, with increasing wood density, the acoustic insulation is also increasing [Kollmann and Côte 1968, Krzysik 1978, Bucur 2006, Kozakiewicz 2012]. However, due to the diversity of wood structure and the complexity of sound phenomena, including a number of accompanying effects (e.g. reflection, deflection and penetration) [Kirpluk 2014], it is always desirable to experimentally verify its sound insulation properties. Insulation is also proportional to the increase in the mass of a partition and the sound frequency [Bucur 2006]. African species of wood have long been present on the European market and they find various applications, also resulting from specific features and properties. High natural durability of many African species, defined in EN 350:2016, and their high density transforming into high strength parameters predestine them for external applications [Kozakiewicz et al. 2010], such as sound absorbing and anti-glare screens in communication arteries. The African wood species are also the material used for solid and layered flooring materials – as horizontal partitions of buildings [Kozakiewicz et al. 2012]. The aim of the study was to determine the sound insulation properties of three African wood species – padouk, bubinga and sapele – popular on the European market.

MATERIAL AND METHOD Samples of selected African wood species (padouk, bubinga, sapele) were used in the study. The tested wood species are used as various types of acoustic barriers in buildings, as well as in acoustic screens [Kozakiewicz 2007, Kozakiewicz et al. 2010]. Selected information on the tested wood species was compiled in Table 1. To determine the sound insulation properties, samples with planed surfaces of 500 mm (longitudinal) x 300 mm (tangential) and the final thickness of 20 mm (radial) were used – samples with a dominant tangential section were selected. After the initial determination of the insulation parameters, the samples were planed down to a thickness of 10 mm, and then to 5 mm; and the acoustic chamber test was repeated for each thickness.

Table 1. The basic information about investigated wood species from Africa [EN 13556:2003; Kozakiewicz and Szkarłat 2004; Kozakiewicz 2006, 2007; Wagenführ 2007; Richter and Dallwitz 2009] Latin name of wood English trade name of wood Description of wood (characteristic structure attribute) (and code) according to EN 13556:2003 Pterocarpus soyauxii African padouk (PTXX) hardwood, diffuse-porous, stored structure, Taub., P. osun Craib small striped grain, paratracheal parenchyma - wing-like, wing-streak apotracheal - dispersed Guibourtia tessmanii bubinga (GUXX) hardwood, diffuse-porous, stored structure, (A.Chev.) J.Léon. small striped grain, paratracheal parenchyma - one-sided apotracheal - diffused Entandrophragma sapele (ENCY) hardwood, diffuse-porous, stored structure, cylindricum (Sprague) strong regular striped grain, Sprague paratracheal parenchyma - narrow around the vascular apotracheal - banded

After bringing the samples to air-dry condition, the wood density was determined by stereometric method in accordance with ISO 13061-2:2014, and moisture content was controlled by electric capacitive method in accordance with EN 13183-3:2005. Prior to proper sound insulation tests, the dynamic modulus of elasticity was also determined using the original ultrasonic methodology. The tests were performed using a UMT-1 material tester equipped with two cylindrical 40 kHz transmitting and receiving heads providing the required signal range. The remaining settings were as follows: 50 dB gain, 60V energy, 12 Hz pulse mode and 8.8 µs latency time. After placing the heads facing each other to the faces of the wooden element covered with ultrasound gel, ultrasound was passed (the measurement was repeated six times along the fibres, successively in lines evenly spaced from each other – determined on the width of the element). Wave time was read via the UMT-LINK program. On such basis, the following values were calculated: – velocity of longitudinal waves: c = L/t where: L – sample length [m] t = t1 - to – real time of longitudinal wave transition [s] t1 – wave transition time read from the computer monitor [s] to – latency time [s] – dynamic modulus of elasticity: E = c2 · g where: g – density [kg/m3]

The testing of wood’s sound insulation properties was carried out in a small chamber with full geometric similarity to large acoustic chambers (rooms). The results of the

5 measurements in “small” model chambers do not differ significantly from the results obtained in acoustic rooms [Godinho et al. 2010, Dukarska et al. 2014, Rey et al. 2019]. The test conditions were based on the standards used for testing the sound insulation properties of building materials [ISO 10140-1:2016 and ISO 10140-2,-3,-4,-5:2010]. The test stand included the following elements: EVENT sound column (sound source), two Behringer ECM 8000 condenser microphones, FireWire 24-bit/96kHz-PreSonus3 interface, acoustic analyzer and EASERA 1.2.10 program for generating, recording and processing acoustic data. Prepared solid wood samples were placed successively in a measuring hole (partition) located between sending and receiving chambers. After placing the samples, an acoustic field stimulated by white noise was generated for 5.5 s. The EASERA program provided diagrams of the intensity of sound on both sides of the partition (samples) in the audible frequency range, i.e. from 20 Hz to 20 000 Hz. Based on the obtained data, the sound insulation (taking into account the background – the difference in the intensity of sound measured without a partition in the transmitting and receiving chamber) was calculated from the following formula: R = SI - SII - So [dB] where: R – sound insulation [dB], SI – signal measured in the sending chamber [dB], SII – signal measured in the receiving chamber [dB], So – difference of signal reading in the sending and receiving chamber without a partition [dB]. Based on the results of insulation performance expressed in decibels, the percentage insulation factor was calculated from the formula: CR% = (R/S) ·100 [%] where: CR% – sound insulation coefficient [%], S – sound level (110 dB).

RESULTS AND DISCUSSION The moisture content of the wood to be tested ranged from 8% to 10% (typical for wood used in rooms in the temperate climate zone). Due to strong saturation with non- structural compounds, exotic species usually take lower equilibrium moisture content compared to wood from a temperate climate [Kozakiewicz et al. 2012]. The results of the density, ultrasonic wave velocity and dynamic modulus of elasticity are given in the Table 2. The density of sapele wood in the air-dry state was 694 kg/m3, bubinga wood 858 kg/m3, and the largest African padouk 868 kg/m3. The marked wood densities are typical (representative) of those individual species. They are in the density ranges given in the literature [Wagenführ 2007, Richter and Dallwitz 2009]. The obtained research results indicate that the velocity of propagation of ultrasonic waves in two denser species of wood (bubinga, padouk) was similar and amounted on average to 4900 - 5000 m/s. Sapele wood containing a striped fibre pattern was characterized by a lower speed (about 4700 m/s) of ultrasonic propagation. Among the tested samples, the bubinga wood sample – 22.07 GPa – had the highest average modulus of elasticity along the fibres. Equally high value was obtained in padouk wood – 21.30 GPa, and the lowest in wood sapele – 15.16 GPa. The last of the mentioned species was also distinguished by the highest variability of the examined feature, which was most likely determined by the presence of a striped arrangement of fibres. The obtained values of the modules marked with the dynamic method are slightly higher than those found in the literature, which refer to the modulus of elasticity determined during static bending [Kozakiewicz and Szkarłat 2004, Wagenführ 2007, Kozakiewicz 2006, 2007].

Table 2. The results of the testing of the physical properties of wood Wood species Density Ultrasonic transition speed Dynamic modulus of elasticity [kg/m3] average (standard deviation in average (standard deviation in parentheses) [m/s] – variation parentheses) [MPa] – variation coefficient [%] coefficient [%] African padouk 868 4950 (43) – 0.87 21.30 (0.37) – 1.74 bubinga 858 5070 (55) – 1.09 22.07 (0.48) – 2.17 sapele 694 4670 (296) – 6.34 15.16 (1.89) – 12.47

Figure 1. Acoustic insulation properties of padouk wood for three different thicknesses of the partition: 20, 10 and 5 mm

Figure 2. Acoustic insulation properties of bubinga wood for three different thicknesses of the partition: 20, 10 and 5 mm

Figure 3. Acoustic insulation properties of sapele wood for three different thicknesses of the partition: 20, 10 and 5 mm

The material intended to fulfil the role of sound absorbing material must have the highest possible absorption coefficient (internal attenuation), as high as possible for the audible frequency range, i.e. 20–20 000 Hz. The law of mass allows approximation of the sound insulation of a single homogeneous partition. This law shows that the increase in insulation is proportional to the increase in bulkhead weight and sound frequency [Bucur 2006]. Generally, tested partitions show similar characteristics of the amount of sound attenuation depending on the wave frequency expressed in dB (Fig. 1, Fig 2, and Fig. 3) and in % in relation to the generated signal (Table 3). In the low frequency range, the characteristics change very dynamically and attenuation can be considered as not very effective. Above 200 Hz, a more even sound reduction characteristic begins. However, each partition is characterized by so-called limit coincidence frequency (frequency band) at which bent waves appear in the partition (resonance appears). Sounds of this frequency are suppressed to a small extent – the so-called sound window occurs (frequency band that is less attenuated compared to other frequencies) [Braune 1960]. In the conducted tests, this phenomenon is visible at a frequency of approx. 300–350 Hz (clear lower insulation of partitions). As the frequency increases further, the insulation increases, gradually reaching at least 20% efficiency in all variants for frequencies above 2 kHz (Table 3). At higher frequencies, there are also more marked differences between the tested wood species. The most effective sound insulation is provided by padouk wood. An analysis of the influence of partition thickness was also an important implication. It turns out that up to a frequency of about 600 Hz, the results were in line with the expectations. Regardless of the type of wood, the thickest partitions were the most effective in sound insulation. At higher frequencies, along with the increase in sound insulation, the effect of partition thickness was no longer so obvious; moreover, this characteristic was different for each species of wood (Fig. 1, Fig. 2, and Fig. 3). It is likely that various anatomical features, in particular fibre arrangement and wood parenchyma distribution, had an impact here. Perhaps in the case of padouk wood, the sound insulation performance (Fig. 1, Table 3) was determined not only by high density but also by the presence of banded parenchyma. Low-density parenchyma bands alternated with thick-walled fibres formed a layered system difficult to overcome by sound waves. Probably also non-straight fibre arrangement (strong, regular striped grain) in sapele wood was the

8 reason for better insulation at high frequencies (Fig. 3, Table 3) compared to small striped fibrous bubinga wood (Fig. 2, Table 3). There was no clear relationship between sound insulation and the value of the modulus of elasticity along the fibres.

Table 3. Acoustic insulation coefficient CR [%] in individual frequency bands Sound Sound insulation coefficient CR [%] frequency African padouk bubinga sapele [Hz] partition thickness [mm] 20 10 5 20 10 5 20 10 5 12.5 9 9 11 7 7 11 11 7 6 16 9 12 10 10 12 11 9 9 11 20 10 9 10 11 7 9 11 12 9 25 15 16 16 18 16 17 16 16 16 31.5 28 27 26 28 27 27 27 26 24 40 28 30 27 27 29 27 28 29 25 50 41 42 40 39 42 38 42 44 31 63 36 38 32 31 34 28 36 36 21 80 16 16 12 23 16 13 18 15 17 100 16 12 15 19 18 17 21 15 16 125 19 12 12 21 15 12 21 13 15 160 18 7 12 16 12 11 16 13 14 200 20 20 15 22 21 15 21 18 16 250 26 23 20 24 23 20 24 22 18 315 18 17 15 17 17 14 17 16 13 400 25 24 20 24 24 20 24 23 18 500 27 25 21 27 24 22 25 23 20 630 27 24 21 27 23 22 26 23 20 800 21 25 21 21 25 19 21 24 18 1k 24 27 24 23 25 23 22 25 21 1.25k 24 30 25 23 28 25 23 29 23 1.6k 24 25 24 21 26 23 23 26 21 2k 24 24 26 18 22 24 24 26 20 2.5k 27 28 28 23 28 27 27 27 27 3.15k 27 27 28 22 23 27 29 30 24 4k 25 29 24 25 28 22 31 28 23 5k 28 31 27 28 31 27 33 32 25 6.3k 30 35 29 31 33 28 36 36 26 8k 31 35 28 25 31 29 31 34 27 10k 32 38 34 26 34 30 32 39 29 12.5k 31 41 37 27 34 34 33 43 35 16k 33 44 41 29 32 35 33 46 37 20k 34 38 42 28 31 34 32 46 39

CONCLUSIONS Based on the tests of sound insulation of solid wood Afican padouk, bubinga, sapele (air-dry planed elements 20, 10 and 5 mm thick) the following conclusions were drawn: 1. The density of padouk and bubinga wood was similar and brought over 850 kg/m3, and the sapele wood was clearly lower, less than 700 kg/m3. The velocity of propagation of ultrasonic waves with a frequency of 40 kHz in two denser wood species (padouk, bubinga) was similar and averaged 5000 m/s. The lowest velocity (about 4700 m/s) of ultrasound propagation was found in sapele wood containing a strong striped arrangement of fibers. This also translated into the values of the dynamic modulus of elasticity.

2. In the frequency range from 20 to 600 Hz the sound insulation characteristics of the tested partitions changed dynamically, but very similarly while maintaining the law of mass. Irrespective of the type of wood, thicker partitions were more effective than thinner ones. 3. In the higher frequency range, the impact of partition thickness on insulation performance was individual, different for each type of wood. In general, the highest insulation properties were shown by the partition of padouk wood, which was probably determined not only by the high density of this wood, but also by the presence of a banded parenchyma alternated with thick-walled fibers that formed a layered system. 4. For partitions with a thickness of 10 mm and 20 mm, the largest differences in sound insulation between the tested species occurred in the frequency range 1 kHz - 20 kHz. In the case of 5 mm thick partitions in the whole frequency range, these differences were at a similar level. REFERENCES

1. BRAUNE B., 1960: Documentation bois. Acoustique. Lignum. Union Suisse en Faveur du Bois. Zürich. 2. BUCUR V., 2006: Acoustics of wood. Springer-Verlag, Berlin Heidelberg. 3. DUKARSKA D., KUSIAK M., DERKOWSKI A., 2014: Non-normative method for determining acoustic insulation of board materials. Annals of Warsaw University of Life Sciences – SGGW, Forestry and Wood Technology 88:56-60. 4. EN 350:2016 Durability of wood and wood-based products – Testing and classification of the durability to biological agents of wood and wood-based materials, European Committee for Standardization, Brussels, Belgium. 5. EN 13183-3:2005 Moisture content of a piece of sawn timber. Estimation by capacitance method. The European Committee for Standardization, Brussels, Belgium. 6. EN 13556:2003 Round and sawn timber – Nomenclature of timbers used in Europe. The European Committee for Standardization, Brussels, Belgium. 7. GODINHO L., MASGALOS R., PEREIRA A., BRANCO F.G., 2010: On the use of a small-sized acoustic chamber for the analysis of impact sound reduction by floor coverings. Noise Control Engineering Journal 58 (6):658-668. 8. ISO 10140-1:2016 Acoustics - Laboratory measurement of sound insulation of building elements - Part 1: Application rules for specific products. International Organization of Standardization, Geneva, Switzerland. 9. ISO 13061-2:2014 Physical and mechanical properties of wood – Test methods for small clear wood specimens – Part 2: Determination of density for physical and mechanical tests. International Organization of Standardization, Geneva, Switzerland. 10. ISO 10140-2:2010 Acoustics – Laboratory measurement of sound insulation of building elements – Part 2: Measurement of airborne sound insulation. International Organization of Standardization, Geneva, Switzerland. 11. ISO 10140-3:2010 Acoustics – Laboratory measurement of sound insulation of building elements – Part 3: Measurement of impact sound insulation. International Organization of Standardization, Geneva, Switzerland. 12. ISO 10140-4:2010 Acoustics – Laboratory measurement of sound insulation of building elements – Part 4: Measurement procedures and requirements. International Organization of Standardization, Geneva, Switzerland. 13. ISO 10140-5:2010 Acoustics – Laboratory measurement of sound insulation of building elements – Part 5: Requirements for test facilities and equipment. International Organization of Standardization, Geneva, Switzerland.

14. KIRPLUK M., 2014: Podstawy akustyki. Edycja poprawiona. NTL-M. Kripluk, Warszawa-http://www.ntlmk.com/M.Kirpluk%20-%20Podstawy%20akustyki%20- %202012-11.pdf 15. KOLLMANN F., CÔTE W.A., 1968: Principles of wood science and technology. Vol. I: Solid wood. Springer-Verlag, Berlin Heidelberg. 16. KOZAKIEWICZ P., SZKARŁAT D., 2004: Sapelli (Entandrophragma cylindricum Sprague) – drewno egzotyczne z Afryki. Przemysł Drzewny 9:27-30. 17. KOZAKIEWICZ P., 2006: Paduk afrykański (Pterocarpus soyauxii Toub.) – drewno egzotyczne z Afryki. Przemysł Drzewny 7-8:25-28. 18. KOZAKIEWICZ P., 2007: Bubinga (Guibourtia tessmanii (A.Chev.) J.Léon.) – drewno egzotyczne z Afryki. Przemysł Drzewny 6:31-34. 19. KOZAKIEWICZ P., KOŚCIELNIAK C., ZAKRZEWSKA-RUDZINSKA W., 2010: Badania właściwości i innowacyjne zastosowania drewna egzotycznego w Polsce. Przemysł Drzewny 4 (59):18-23. 20. KOZAKIEWICZ P., 2012: Fizyka drewna w teorii i zadaniach. Wydanie IV zmienione. Wydawnictwo SGGW. Warszawa. 21. KOZAKIEWICZ P., NOSKOWIAK A., PIÓRO P., 2012: Atlas drewna podłogowego. Wydanie I. Wydawnictwo „Profi-Press” Sp. z o.o. Warszawa. 22. KRZYSIK F., 1978: Nauka o drewnie, Państwowe Wydawnictwo Naukowe, Warszawa. 23. REY R., ALBA J., RODRÍGUEZ J.C., BERTÓ L., 2019: Characterization of new sustainable acoustic solutions in a reduced sized transmission chamber. Buildings 9:60. 24. RICHTER H.G., DALLWITZ M.J., 2009: Commercial timbers: descriptions, illustrations, identification, and information retrieval. In English, French, German, Portuguese, and Spanish. Version: 25th June 2009 - http://delta-intkey.com 25. WAGENFÜHR R., 2007: Holzatlas 6, neu bearbeitete und erweitere Auflage. Mit zahlreichen Abbildungen. Fachbuchverlag Leipzig im Carl Hanser Verlag, München.

Streszczenie: Izolacyjność akustyczna wybranych gatunków drewna afrykańskiego: paduk, bubinga, sapeli. Afrykańskie gatunki drewna obecne na rynku europejskim znajdują różnorodne zastosowania wynikające również ze specyficznych cech i właściwości. Wysoka naturalna trwałość oraz znaczna gęstość przekładająca się na wysokie parametry wytrzymałościowe predestynuje je do zastosowań zewnętrznych między innymi na ekrany dźwiękochłonne i przeciw olśnieniowe przy ciągach komunikacyjnych. Ze względu na walory estetyczne są też stosowane w materiałach podłogowych i okładzinach ściennych. W zastosowaniach tych istotna jest również izolacyjność akustyczna. Badania przeprowadzono w małej komorze akustycznej po wytworzeniu pola akustycznego pobudzonego szumem białym w czasie 5,5 s. Poziom natężenia dźwięku generowanego przez głośnik wynosił 110 dB. W obrębie każdego gatunku grubość przegród wynosiła 20, 10 i 5 mm. Badania poprzedzono określeniem wilgotności, gęstości i dynamicznego modułu sprężystości drewna. W przedziale częstotliwości od 20 do 600 Hz charakterystyki izolacyjności akustycznej badanych przegród zmieniały się dynamicznie, ale bardzo podobnie przy zachowaniu prawa masy. W zakresie wyższych częstotliwości wpływ grubości przegrody na izolacyjność miał charakter indywidualny, odmienny dla każdego gatunku drewna. Najwyższą izolacyjnością charakteryzowały się przegrody z drewna paduka, o czym najprawdopodobniej zadecydowała nie tylko wysoka gęstość tego drewna, ale również obecność miękiszu pasmowego ułożonego na przemian z grubościennymi włóknami, które tworzyły układ warstwowy.

Corresponding author:

Agnieszka Laskowska  Department of Wood Sciences and Wood Preservation Faculty of Wood Technology Warsaw University of Life Sciences – SGGW 159 Nowoursynowska St. 02-776 Warsaw, Poland email: [email protected], phone: +48 22 59 38 661

ORCID ID: Kozakiewicz Paweł 0000-0002-2285-2912 Agnieszka Laskowska 0000-0001-6212-3100

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 13-18 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Bamboo as an innovative material for many branches of world industry

PIOTR F. BOROWSKI Institute of Mechanical Engineering, Faculty of Production Engineering, Warsaw University of Life Sciences - SGGW

Abstract: The article presents bamboo as a material that can be used in many branches of industry. The widespread occurrence of bamboo, its rapid growth and very good physico-chemical properties make it a convenient and easily available material in many countries all over the world. Results of some preliminary research carried out in Ethiopia and Guinea show wide range of bamboo applications and the possibilities of its use in Polish conditions. Secondary research based on available sources indicates the promising direction of future development of the economy based on bamboo use.

Keywords: bamboo, industry, energy, climate

INTRODUCTION Bamboo is the widespread term applied to a wide group of large woody grasses ranging from 10 cm to 40 m in height. They grow in the tropical and subtropical regions of Latin America, Africa and Asia, extending as far north as the southern United States or central China, and as far south as Patagonia. Bamboo also grows in the northern part of Australia (Fig. 1).

Figure 1. Map of bamboo growth around the world Note: Dark colour indicates countries with active bamboo growth. Source: based on bambooimport.com

Bamboo is already in everyday use by about 2.5 billion people, mostly for fibber and food mostly in Asia. The subfamily Bambusoidaea consists of both woody and herbaceous bamboos with 1575 identified species in 111 different genera. However, bamboo may have a potential as a bioenergy or fibre crop for niche markets, although some reports of its high productivity seem to be exaggerated. Literature on bamboo performance is still scarce (in comparison with that on other materials), with most reports coming from various parts of Asia. There is little evidence overall that bamboo is significantly more productive than many other candidate bioenergy crops, but it shares a number of desirable fuel characteristics with certain other bioenergy feedstocks, such as low ash content and alkali index. Its heating value

13 is lower than many woody biomass feedstocks but higher than most agricultural wastes and residues, grasses and straws. Although non-fuel applications of bamboo biomass may be actually more gainful than energy recovery, there may also be potential for co-production of bioenergy together with other bamboo processing (Scurlock et. al., 2000). Qualitative market research methods which include focus group studies, in-depth interviews and observational techniques (Belk 2008) were applied. In this study, the following market research methods were used: (1) observation, (2) primary research and (3) secondary research (Creswell 2009). The author carried out series of research listed above on site in Guinea and Ethiopia. Observations and primary research in Guinea were carried out directly within April–May and August–September 2015, whereas desk research were realized as ongoing study. A research project in Ethiopia was realized in September 2014 and May–June 2016. In Guinea-Conakry bamboo and rattan stems are booming in the market of Conakry (capital city) and some of the country’s major cities. Mainly bamboo is used to produce poles, stakes and round woods. Bamboo is used for a wide variety of uses: roofing, scaffolding, dry tapades, sheds, rustic bridges, barbed wire stands, etc. Currently there is no precise knowledge about the annual production and consumption of this product (FOSA, 2001). Ethiopia has over 60% of Africa’s natural bamboo, but it has never really been used. Ethiopia has an estimated one million hectares of natural bamboo forest, the largest in the African continent. It is green gold and should be given special attention. There 2 bamboo species considered to be native of Ethiopia: Oxytenanthera abyssinica (lowland bamboo) and Yushania arundinaria alpina (highland bamboo). In 2015, Ethiopia was the 9th largest exporter of bamboo raw materials in the world (King, 2019).

BAMBOO INLUENCE FOR THE CLIMAT PROTECTION Bamboo is particularly suitable as a tool for carbon sequestration. Bamboo’s carbon sequestration properties have been studied in Mexico and China, where it naturally forms wild forests. The most effective solution to climate change is the abatement of CO2 (carbon dioxide) emission by reducing our dependence on fossil fuels. As a result of its unbelievable system of roots, bamboo continues to grow irrespectively after being harvested. In contrast to most other plants bamboo are low cost plants, in meaning that they don’t require fertilizer, chemicals or pesticides in order to grow. Bamboos can be called self-care plants because they utilise their own fallen leaves to supply them with nutrients when disintegrated into the soil. Due to its incredibly rapid growth cycle and the variety of areas in which it is able to grow, bamboo is also extremely cheap. The first days of bamboo growing is shown in Figure 2.

10 y = 0.0012x3 - 0.0077x2 + 0.0268x + 0.0273 R² = 0.9997 8

Height [meter]Height 4

0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time [day]

Figure 2. The dynamics of bamboo growth. Source: https://lewisbamboo.com/growth-chart-of-bamboo/

The dynamics of bamboo growth is characterised with rapid increase in the second and third week. It is observed that during the first 12 days a new bamboo can grow about 6 cm per day, 37 cm in another 4 days, while the third week brings a daily growth of about 80 cm. Such rapid growth requires the grass to absorb large quantities of CO2, meaning that its cultivation as a building material would help reduce the rate of climate change. Over a period of 30 years, bamboo plants and products can store more carbon than certain species of trees. This is mainly because bamboo can be harvested regularly, creating a large number of durable products which store carbon over several years, in addition to the carbon stored in the plant itself. If the world planted an additional 10 million hectares of bamboo on degraded lands, it is estimated that bamboo plants and their products could save over 7 gigatons of CO2 (carbon dioxide) within 30 years. That is more than 300 million new electric cars could save in the same time period. Importantly, this statistic does not include the emissions saved by substituting aluminium, concrete, plastic, or steel for bamboo. Bamboo has huge strength and flexibility making it an ideal building and construction material in many parts of Africa, Asia and Latin America where it is native. Bamboo has a tensile strength greater than that of mild steel, and withstands compression twice as well as concrete, making it a ready replacement in roads, drainage pipes, housing and even wind turbine blades (King, 2019). In table 1 basic strength properties for bamboo and other materials were presented.

Table 1. Mechanical properties of bamboo, spruce wood and steel Properties [kN/cm2] Bamboo Spruce wood Steel

Modulus of elasticity 2000 1100 21000

Compressive strength 6.2–9.5 4.3 14.0

Tension strength 14.8–38.4 8.9 16.0

Bending strength 7.6–27.6 6.8 14.0

Shear strength 2.0 0.7 9.2

Source: GUTU, T. A study on the mechanical strength properties of bamboo to enhance its diversification on its utilization. International Journal of Innovative Technology and Exploring Engineering, 2013, 2.5: 314–319.

CHALLENGES AND OPPORTUNITIES FOR BAMBOO PRODUCTION IN POLAND Bamboo is a diverse plant that easily adopts to different climate and landscape condition. It can grow in a wide variety of soil types, different temperatures and humidity conditions. For Poland’s climate, there are dozens of varieties of cold hardy bamboo to consider. Most of them belong to either the Phyllostachys or the Fargesia group (genus) of bamboo. Phyllostachys is one of the most prevalent genera of bamboo, primarily native to China and including about 50 distinct species. Almost every species of Phyllostachys is a fast spreading runner (with an aggressive rhizome root system), and many of them are cold hardy, down to minus 15–20 oC. Among the varieties which can be grow in Poland are the following: Incense Bamboo (Phyllostachys atrovaginata), fine-leaved Phyllostachys parvifolia, and Ink-finger (Phyllostachys nuda). Fargesia is another major genus of bamboo, also indigenous to China and southeast Asia. Unlike Phyllostachys, the Fargesia bamboos are chiefly dense growing clumpers. This and their cold hardiness have made many varieties of Fargesia very popular among gardeners. In Poland, the following varieties will cope well with the climate: Blue fountain bamboo (Fargesia nitida), umbrella bamboo (Fargesia murielae), and Clumping bamboo, also called “non-running bamboo” (Fargesia rufa).

It is worth noting that in Poland with a transient climate (between maritime and continental climate) there are very clear differences in wintering conditions for plants in individual regions. In the Pomeranian zone and in the western part of the country, down to Lower Silesia, the conditions for growing a more sensitive plants are favourable, in the majority of central Poland – moderate, and in the Podlasie province, Lublin, North East part of the Masovia province, Mazury and in the mountains – difficult (see Fig. 3).

Figure 3. Conditions for wintering sensitive plants in Poland Source: Hoser Sz. Fargesia www.ragesia.pl

Almost every species of Phyllostachys is a fast spreading runner (with an aggressive rhizome root system), and many of them are cold hardy, down to minus 15–20 oC. Among the varieties which can be grow in Poland are the following: Incense Bamboo (Phyllostachys atrovaginata), fine-leaved Phyllostachys parvifolia, and Ink-finger (Phyllostachys nuda). Fargesia is another major genus of bamboo, also indigenous to China and southeast Asia. Unlike Phyllostachys, the Fargesia bamboos are chiefly dense growing clumpers. This and their cold hardiness have made many varieties of Fargesia very popular among gardeners. In Poland, the following varieties will cope well with the climate: Blue fountain bamboo (Fargesia nitida), umbrella bamboo (Fargesia murielae), and Clumping bamboo, also called “non-running bamboo” (Fargesia rufa). It is worth noting that in Poland with a transient climate (between maritime and continental climate) there are very clear differences in wintering conditions for plants in individual regions. In the Pomeranian zone and in the western part of the country, down to Lower Silesia, the conditions for growing a more sensitive plants are favourable, in the majority of central Poland – moderate, and in the Podlasie province, Lublin, North East part of the Masovia province, Mazury and in the mountains – difficult (see Fig. 3).

BAMBOO AS A RENEWABLE SOURCE OF ENERGY PRODUCION Bamboo may, indeed, have potential as a bioenergy or fibre crop for niche markets. Bamboo has good fibre quality for paper-making, and it shares a number of desirable fuel characteristics with certain other bioenergy feedstocks, such as low ash content and alkali index. The principal ash-forming constituents in bamboo are silica (SiO2) and potassium (K2O). It also contains calcium (CaO), chlorine (Cl) and magnesium (MgO) (Kumar, Chandrashekar, 2014). To evaluate the quality of biofuels, it is important to know the content

16 of sulphur and chlorine. A high content of these elements is causing corrosion and contamination of boilers and increased emissions of Cl2, SOx and HCl. Since the plant’s health is improved by cutting, bamboo can be re-harvested every three years without any harmful effects to the environment. With the average 500-year life span of a redwood tree, a bamboo plant could be harvested and regrown more than 150 times. Bamboo biomass energy has great potential to be an alternative for fossil fuel. Biomass of bamboo comes from culms, branches and leaves. Bamboo biomass can be processed in various ways (thermal or biochemical conversion) to produce different energy products (charcoal, syngas and biofuels), which can be substitutions for existing fossil fuel products. Bamboo biomass alone cannot fulfil all the demand for energy. It needs to combine with other sources to best exploit their potential and provide sustainable energy supply (Le, Truong, 2014). Bamboo biomass is characterized by a relatively higher heating value than other sorts of biomass, which means it is a good material for direct combustion (e.g. co-combustion in thermal power plant). Many projects on bamboo energy are operating or being implemented all over the world. In African countries, bamboo biomass projects are very popular and mostly used to replace firewood or produce charcoal for domestic use.

BAMBOO AS A ADDITIONAL MATERIAL FOR BIODEGADATION In Europe, much research of biodegradable materials is conducted. In some materials, pine wood dust is added to change the properties of biodegradable materials (Żelaziński et al., 2019) but also bamboo can improve the results and properties of materials. The biocomposite samples reinforced with raw bamboo fibre and treated showed different degree of biodegradation with weight loss after 30 days of analyses. In general, the biodegradability studies showed that raw bamboo fibre and the biocomposite reinforced with this fibre were more resistant to the action of the microorganisms due to a higher contents of lignin and hemicelluloses. In the plant tissue, lignin acts as a reinforcement, just like cement, between the fibres (Junior et al., 2014).

CONCLUSION In Europe, specifically in Poland, the cultivation of, but above all, the production of bamboo can achieve a high level of innovation. Europe today has technological advances in some areas of economy and industry such as the micro-propagation, the selection of superior genotypes using molecular markers and biomass gasification for energy production. Any widespread bamboo production implies an industrial use. In a short term perspective, bamboo can be produced and used for soil stabilisation, riparian improvement, wind protection, poles for viticulture or fruit trees, small sticks for horticulture. At medium term bamboo can find utilisation for vannerie and furniture production. Also arts and craft could be considered as an ideal utilisation for everyday equipment. In a long term perspective, bamboo utilisations for industrial purposes require supplementary analyses and tests. Two of them seem of major importance: determination of calorific value for gasification and defibration for the production of boards or biodegradable textiles.

REFERENCES

1. BELK R.W. (2008): Handbook of Qualitative Research Methods in Marketing (Elgar Original Reference), Edward Elgar Publishing. 2. CICHY W., WITCZAK M., WALKOWIAK M., 2018: The assessment of fuel properties of pellets made from wood raw materials, Ann. WULS - SGGW, For. and Wood Technol., 101, 85-90. 3. CRESWELL, J.W. (2009): Research Design: Qualitative, Quantitative and Mix Methods Approaches. Sage Publication Inc. 17

4. FOSA, 2001: L’Etude prospective du secteur forestieren Afrique (FOSA), l’Etude prospective du secteur forestieren Afrique – Guinée, Juillet, 07, 1-41. 5. GUTU T. A., 2013: study on the mechanical strength properties of bamboo to enhance its diversification on its utilization, International Journal of Innovative Technology and Exploring Engineering, 2 (5), 314-319. 6. JUNIOR, A.E. C., et al., 2015: Thermal and mechanical properties of biocomposites based on a cashew nut shell liquid matrix reinforced with bamboo fibers. Journal of Composite Materials, 49.18: 2203-2215. 7. KING Ch., 2019: Bamboo and Sustainable Development: A Briefing Note, INBAR, 1- 8. 8. KUMAR R., CHANDRASHEKAR N., 2014: Fuel properties and combustion characteristics of some promising bamboo species in India. Journal of Forestry Research, 25 (2), 471-476. 9. LE T.M.A., TRUONG H., 2014: Overview of bamboo biomass for energy production, halshs-01100209. 10. MEKONNEN Z., et al. 2014: Bamboo Resources in Ethiopia: Their value chain and contribution to livelihoods. Ethnobotany Research and Applications, 12: 511-524. 11. SCURLOCK J. M. O., DAYTON D. C., HAMES B., 2000: Bamboo: an overlooked biomass resource? Biomass and bioenergy, 19 (4), 229-244. 12. ŻELAZIŃSKI T., EKIELSKI A., TULSKA E., VLADUT V., DURCZAK K., 2019: Wood Dust Application for Improvement of Selected Properties of Thermoplastic Starch, Inmatech – Agricultural Engineering, 58 (2), 37-43.

Streszczenie: Bambus jako innowacyjny materiał dla wielu gałęzi przemysłu światowego. W artykule przedstawiono bambus, jako materiał, który można wykorzystać w wielu gałęziach przemysłu. Powszechne występowanie bambusa, jego szybki wzrost i bardzo dobre właściwości fizykochemiczne sprawiają, że jest to materiał wygodny i łatwo dostępny w wielu krajach na całym świecie. Wstępne wyniki badań przeprowadzonych w Etiopii i Gwinei pokazują szerokie możliwości wykorzystania bambusa i możliwości jego implementacji w polskich warunkach. Badania wtórne oparte na dostępnych źródłach wskazują na duży potencjał wykorzystywania bambusa w wielu branżach gospodarki.

Corresponding author:

Piotr F. Borowski Institute of Mechanical Engineering, Faculty of Production Engineering, Warsaw University of Life Sciences - SGGW ul. Nowoursynowska 166 02-787 Warszawa email: [email protected] phone: +48225934557

ORCID ID: Borowski Piotr F. 0000-0002-4900-514X

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 19-23 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019) A comparison of methods for obtaining nanocellulose using acid and ionic liquid hydrolysis reactions MARTA BABICKA1, KRZYSZTOF DWIECKI2, IZABELA RATAJCZAK1 1Poznań University of Life Sciences, Department of Chemistry, Wojska Polskiego 75, PL-60625 Poznan, Poland 2Poznań University of Life Sciences, Department of Food Biochemistry and Analysis, Mazowiecka 48, PL- 60623 Poznan, Poland

Abstract: A comparison of methods for obtaining nanocellulose using acid and ionic liquid hydrolysis reactions. In this study, two methods were compared, i.e. acid hydrolysis using sulphuric acid (VI) and ionic liquid hydrolysis using 1-methyl-3-butylimidazolium chloride to obtain nanocellulose from Sigmacell Cellulose Type 20. The efficiency of both processes was tested for weight loss of the material during the reaction. The study showed that much more material can be obtained using ionic liquid hydrolysis than using acid hydrolysis. A dynamic light scattering study was performed to determine material particle size before and after these processes. Particles of nanometric size were recorded only for cellulose after the reaction with an ionic liquid. In addition, Fourier transform infrared spectroscopy was performed to determine the chemical structure of the materials tested.

Keywords: 1-butyl-3-methylimidazolium chloride, sulphuric acid(VI), acid hydrolysis, ionic liquid hydrolysis, Dynamic Light Scattering, Fourier Transform Infrared Spectroscopy

INTRODUCTION Nanometric size cellulose and the methods of its production are very popular research topics, as evidenced by the number of publications in recent years (Ribeiro et al. 2019). This is due to the increasing use of this material and attempts to develop a method that would be cost-effective and safe for the environment (Bhat et al. 2019). Nanocellulose may be obtained through affecting a factor capable of resolving strong interfibrillar hydrogen bonds within the molecule. This ability is found in strongly corrosive acids and bases, some ionic liquids, cellulose enzymes or mechanical forces (Jiang and Hsieh 2013).

Figure 1. Chemical structure of [Bmim] [Cl]

Nickerson and Habrle (1947) were the pioneers of nanocellulose production by acid hydrolysis. It has been shown that sulphuric acid may be used for cellulose hydrolysis, but different nanoparticle dimensions (from 3 to 70 nm wide and from 35 to 3000 nm long) were obtained depending on the cellulose source and reaction conditions (Beck-Candanedo, et al. 2005; Elazzouzi-Hafraoui et al. 2008; Habibi et al. 2010). Strong acids, such as hydrochloric acid and hydrobromic acid, also hydrolyze but usually providing low yields of less than 30% (Jiang and Hsieh 2013). However, acids are dangerous for the environment and for its protection various methods are being developed not involving toxic substances.

Ionic liquids are considered non-toxic and eco-friendly. Additionally, thanks to their unique properties they have found numerous applications in new fields, including nanocellulose production (Shak et al. 2018). In 2002, Swatlowski and his team proved that 1- butyl-3-methylimidazolium chloride [Bmim] [Cl] is capable of dissolving cellulose with no need for other solvents. Since this discovery there has been a growing interest in the use of ionic liquids to dissolve and modify cellulose (Suzuki et al. 2014). In this study two methods to obtain cellulose of nanometric size were compared. The acid hydrolysis method, first proposed for the chemical preparation of nanocellulose, was compared with hydrolysis of ionic liquid ([Bmim] [Cl]) (Figure 1). The experiments were conducted on microcrystalline cellulose: Sigmacell Cellulose Type 20 with 20 μm particle size.

MATERIALS The research used microcrystalline cellulose – Sigmacell Cellulose Type 20 with 20 μm particle size (Sigma Aldrich). Moreover, the following chemical substances were used: sulfuric acid (VI) 95% (Sigma Aldrich) was diluted to 64% with water, anhydrous NaOH (Sigma Aldrich) for acid neutralization and 1-butyl-3-methylimidazolium chloride (≥98%) (Sigma Aldrich) as ionic liquid, phosphorus pentaoxide (P2O5) (Sigma-Aldrich), acetonitrile (Sigma-Aldrich), KBr (Sigma-Aldrich).

METHODS Preparation of nanocellulose using acid hydrolysis reaction Microcrystalline cellulose (Sigmacell) was mixed with H2SO4 (64%) at a 1:10 ratio (m/v). The suspension was subjected to constant magnetic stirring (ChemLand, Poland). The reaction was run at two temperatures (25 °C and 45 °C) for 1 min and 5 min. Cold water was added to terminate the reaction and sulfuric acid (VI) was neutralized by sodium hydroxide. The material was centrifuged and rinsed with water. The cellulose was dried in a dryer (Pol- Eko, Poland) and, in the final stage, placed in a desiccator over P2O5. Preparation of nanocellulose using ionic liquid hydrolysis reaction Microcrystalline cellulose (Sigmacell) was added to the molten ionic liquid [Bmim] [Cl] at a 1:10 ratio (w/w). The reaction was run for 9 hours at 90 °C, with intensive magnetic stirring (ChemLand, Poland). After hydrolysis the reaction product was filtered and washed thoroughly with acetonitrile to remove the ionic liquid. In the next stage of the study, the cellulose material was left to dry at a room temperature and, in the final stage, it was placed in a desiccator over P2O5. Fourier transform infrared spectroscopy (FTIR) The samples were mixed with KBr (Sigma Aldrich) at a 1:200 mg ratio and, in the form of pellets, were analyzed by FTIR. Spectra were registered at a range of 4000-500 cm-1, at a resolution of 2 cm-1 and registering 16 scans using a Nicolet iS5 spectrophotometer (Thermo Fisher Scientific, USA). Dynamic light scattering analysis (DLS) DLS was used to determine the particle size (hydrodynamic diameter) of the materials. The samples were previously mixed (2 mg) with 5 ml deionized water, treated using an ultrasound system (Polsonic, Poland) for 25 min and next centrifuged using an incubated shaker (Jeio Tech, Korea) in order to remove the micrometric fraction of cellulose. Finally, the hydrodynamic diameter of samples was determined with a Zetasizer Nano ZS-90 (Malvern Instruments Ltd., UK) at room temperature, with the results presented as size distribution by intensity.

RESULTS The dried material was weighed to calculate the efficiency of the hydrolysis reaction process. The results are shown in Table 1. The efficiency of nanometric cellulose production in the hydrolysis reaction was higher in milder reaction conditions. After a reaction of 1 min at 25°C, the reaction yield was 60%, while after a reaction of 5 min. at 25°C and 1 min at 45°C, the yield was close to 30%. The lowest result was registered for the 5 min reaction at 45°C (5%). A much higher yield was obtained during hydrolysis with the ionic liquid (89%), despite a longer reaction time and a higher temperature. Another test was performed using FTIR spectra to determine the chemical structure of the resulting materials (Figure 2). Additional bands were recorded in the cellulose spectrum after hydrolysis with an ionic liquid, which are not present in the spectra after acid hydrolysis. Wave numbers of 1575 cm−1 are due to C=N stretchings. The peak at the wave number of 757 cm−1 is due to C–N stretching vibration. These bands correspond to the ionic liquid 1-butyl-3- methylimidazolium chloride, which was not eluted from the cellulose sample, similarly as in a study of Dharaskar et al. (2013). An increase in the intensity of the “crystallinity band”, which -1 corresponds to CH2 bending vibrations, was recorded at 1466 cm for cellulose after hydrolysis with the ionic liquid. At the same time, a decrease in the intensity of the “amorphous band” was recorded at 815 cm-1, which corresponds to the C-O-C tensile vibration at β- (1 → 4) -glycosidic bonds.

Table 1. The efficiency of the acid and ionic liquid hydrolysis reactions Hydrolysis reaction Conditions Efficiency [%] 1 min, 25°C 60 5 min, 25°C 35 Acid 1 min, 45°C 28 5 min, 45°C 5 Ionic liquid 24 h, 90°C 89

This indicates an increase in the crystallinity of the cellulose sample after hydrolysis with the ionic liquid (Adsul et al. 2012). In the case of the cellulose sample after acid hydrolysis, no changes in intensity were recorded in these areas, therefore it may be concluded that cellulose crystallinity did not change, either.

Figure 2. FTIR spectra of cellulose (A); cellulose after the acid hydrolysis reaction (B) and the ionic liquid hydrolysis reaction (C)

Another study was performed to determine the particle size of the materials. The results are shown in Figure 3. For samples following acid hydrolysis, no particles below 100 nm were recorded. The result for cellulose after a reaction of 5 min. at 45°C was very similar to that for the native material, while the particle size after hydrolysis with an ionic liquid was below 100 nm. This showed that the ionic liquid hydrolysis was a better choice for obtaining cellulose nanometre sizes. The limited weight loss of cellulose during this process further strengthens this belief. Mao and his co-workers reported a very similar size of nanocellulose molecules using an ionic liquid with the same cation, but at a much lower yield (Mao et al. 2015).

CONCLUSIONS After analyzing the amounts and particle size of the material recovered after the hydrolysis reaction, it may be concluded that the use of an ionic liquid to obtain nanocellulose was more favourable than the use of sulphuric acid(VI).

Figure 3. The average particles size of the cellulose before and after treatment with ionic liquid and acid

The yield for the ionic liquid reaction was higher than in all the acid tests. Nanometric particles were registered only for the material after ionic liquid hydrolysis. Based on the analysis of FTIR spectra, it may be stated that the degree of cellulose crystallinity after the ionic liquid hydrolysis increased, while no changes were recorded for cellulose after the acid hydrolysis. In the FTIR spectra of samples after hydrolysis with ionic liquid, bands corresponding to the ionic liquid were recorded, which may be due to insufficient washing of the material.

REFERENCES

1. ADSUL M., SON S.K., BHARGAVA S.K., BANSAL V. 2012: Facile Approach for the Dispersion of Regenerated Cellulose in Aqueous System in the Form of Nanoparticles. Biomacromolecules 13(9): 2890-2895

2. BECK-CANDANEDO S., ROMAN M., GRAY D. G. 2005: Effect of reaction conditions on the properties and behaviour of wood cellulose nanocrystal suspensions. Biomacromolecules 6(2): 1048-1054 3. BHAT A. H., KHANB I., USMANI M. A., UMAPATHI R., AL-KINDY S. 2019: Cellulose an ageless renewable green nanomaterial for medical applications: An overview of ionic liquids in extraction, separation and dissolution of cellulose, International Journal of Biological Macromolecules 129: 750-777 4. DHARASKAR S. A., VARMA M. N., SHENDE D. Z., YOO C. K., WASEWAR K. L. 2013: Synthesis, Characterization and Application of 1-Butyl-3 Methylimidazolium Chloride as Green Material for Extractive Desulfurization of Liquid Fuel. The Scientific World Journal 2013: 1-9 5. ELAZZOUZI-HAFRAOUI S., NISHIYAMA Y., PUTAUX J. L., HEUX L., DUBREUIL F., ROCHAS C. 2008: The shape and size distribution of crystalline nanoparticles prepared by acid hydrolysis of native cellulose. Biomacromolecules 9(1): 57-65 6. HABIBI Y., LUCIA L. A., ROJAS O. J. 2010: Cellulose nanocrystals: chemistry selfassembly, and applications. Chemical Reviews 110(6): 3479-3500 7. JIANG F., HSIEH Y. L. 2013: Chemically and mechanically isolated nanocellulose and their self-assembled structures, Carbohydrate Polymers 95: 32-40 8. MAO J., HECK B., REITER G., LABORIE M. P. 2015: Cellulose nanocrystals’ production in near theoretical yields by 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim]HSO 4 ) – mediated hydrolysis. Carbohydrate Polymers 117: 443-451 9. NICKERSON R. F., HABRLE, J. A. 1947: Cellulose intercrystalline structure. Industrial & Engineering Chemistry 39(11): 1507-1512 10. RIBEIRO R. S. A., POHLMANN B. C., CALADO V., BOJORGE N., PEREIRA N. 2019: Production of nanocellulose by enzymatic hydrolysis: Trends and challenges. Engineering in Life Sciences 19: 279-291 11. SHAK K., PANG Y., MAH S. 2018: Nanocellulose: Recent advances and its prospects in environmental remediation. Beilstein Journal of Nanotechnology 9: 2479- 2498 12. SUZUKI T., KONO K., SHIMOMURA K., MINAMI H. 2014: Preparation of cellulose particles using an ionic Journal of Colloid and Interface Science 418: 126- 131 13. SWATLOSKI R., SPEAR S., HOLBREY J., ROGERS R. 2002: Dissolution of cellulose with ionic liquids. Journal of the American Chemical Society 124: 4974- 4975

Corresponding author:

Izabela Ratajczak Poznań University of Life Sciences Department of Chemistry Wojska Polskiego 75 PL-60625 Poznan, Poland e-mail: [email protected]

ORCID ID: Babicka Marta 0000-0001-9844-3974

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 24-30 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019) Comparison results of visual and machine strength grading of Scots pine sawn timber from the Silesian Forestry Region in Poland

SŁAWOMIR KRZOSEK, IZABELA BURAWSKA-KUPNIEWSKA, PIOTR MAŃKOWSKI, MAREK GRZEŚKIEWICZ Faculty of Wood Technology, Warsaw University of Life Sciences – SGGW

Abstract: Comparison results of visual and machine strength grading of Scots pine sawn timber from the Silesian Forestry Region in Poland. The paper presents an analysis of the strength grading results performed by two methods – visual (appearance) and machine, carried out for sawn timber obtained from the Silesian Forestry Region in Poland. Visual strength grading was performed in accordance with PN-D-94021:2013, while the machine strength grading with the use of MTG device from Brookhuis Electronics BV. As a result of the tests, it was confirmed that the machine grading results in a very small share of sawn timber classified as rejects. At the same time, during machine strength grading there were some sawn timber pieces that were not classified for any class or a reject. Based on its visual appearance, such timber elements should be graded as rejects.

Keywords: strength grade, Scots pine sawn timber, Polish structural timber, visual grading, mechanical grading

INTRODUCTION The importance of timber used in construction increases year by year. From the material fulfilling auxiliary functions in traditional construction and used mainly on roof trusses and for interior finishing, wood has become a construction material. In modern timber structures several main techniques can be distinguished: classic frame buildings, assembled from scratch at the building site or made in prefabrication technology. Prefabrication involves the production of complete building components in a factory, and then assemble on the construction site. In terms of prefabrication, panel prefabrication can be distinguished, which results in finished walls as well as volume prefabrication, in which the outcome is ready-made modules, which, after being transported to the construction site, allow for the immediate assembly of a whole, even a multi-storey building. In Poland prefabrication technology is already used to build timber structures with 4 floors (Beśka 2018). Cross-linked structural slabs (CLT) are getting more and more popular. Buildings with 14 storeys were built in the world using these modern materials, e.g. in Norway (Abrahamsen and Malo 2014), then 18 storeys in Canada (Fast 2016) or in Norway (Abrahamsen 2017). One of the necessary conditions for safe building with timber is the use of wood with adequate strength parameters. Sawn timber used in construction for structural purposes must be subjected to strength grading. There are two methods for strength grading of structural sawn timber: visual and machine. Strength grading by visual methods consists of a thorough examination of each piece of sawn timber and its qualification into specific grade classes on the basis of noticed wood structure defects, and shape and processing defects. In visual grading, the following wood features and defects are taken into account: knots, grain deviation, cracks and fissures, resin pockets, bark pockets, rot and insect tunnels, shape deviations, etc. Shape and processing defects are wanes, longitudinal (sides and planes) curvatures, transversal curvatures, twists and other cutting defects, such as mechanical damage or exceeding dimensional tolerances. As a result of visual grading, timber is sorted into specific sorting classes. Each of the EU countries has its own national regulations regarding strength grading of sawn timber by the visual method. Following this, there are distinct sorting classes in different countries and there are different methods of assessing timber features, e.g. knottiness. These standards are

24 historically conditioned, they differ in terms of grading criteria and the number of grade classes. Strength grading by visual method in Poland is carried out on the basis of PN/D- 94021:2013. Conifer constructional timber graded with strength methods. As a result of grading sawn timber is qualified into KW – high quality, KS – medium and KG – low. Sawn timber that does not meet the requirements of KG grade class is not suitable for structural applications and call a reject. Strength grading by the visual method is a slow and time-consuming process. The efficiency of such grading in m3 per hour is low. Moreover, it is always burdened, to a greater or lesser extent, with a subjective “human factor” – the result of such grading depends on who grades the timber. If two graders sort the same batch of timber, the grade results may not be identical. Graders are aware of the responsibility and consequences of making an error; in ambiguous situations (so-called border pieces), they tend to lower the grade class of timber subconsciously. Therefore, the first machines for strength grading of sawn timber were designed already in the middle of the last century. Such machines should meet several basic requirements, the most important are:  a possibility to grade full-size structural timber,  ensuring of non-destructive grading. Due to the second requirement, machines for the strength grading of timber are based on the measurement of certain characteristics of wood, which can be determined in a non- destructive manner and which are known to correlate with the bending strength. The higher the correlation between the wood characteristic tested by the machine and its bending strength, the more reliable sorting results of this machine. Because of the use of grading machines, the obtained results are objective; moreover, modern automated machines sort with efficiency much higher than human. Automatic, computer-controlled, very efficient machines (e.g. feed speed of up to 200 m/min) can be integrated into automatic technological lines for the production of, for example, laminated timber (German: BSH – Brettschichtholz, English glulam), solid timber construction glued to length (German: KVH – Konstruktionsvollholz) or CLT (Cross Laminated Timber). In such automatic lines grading machines are joined with the following circular saws, which cut out fragments of boards with unacceptable wood defects. Mechanical strength sorting has already been in use for over 50 years. For the first time, on an industrial scale, devices dedicated to strength grading were used in 1963 in the United States. In Europe, many different designs have been developed and applied on an industrial scale over the past years, some of them have already been the subject of publications by various authors (Denzler et al. 2005, Glos 1982, Krzosek 1995, Krzosek 2009, Krzosek and Bacher 2011). The most important advantage of strength grading by machine method is classifying of sawn timber directly to grades C, according to EN 338:2016 (in Poland PN-EN 338:2016 Timber structures – Strength classes). This standard introduced the following classes for coniferous timber: C14, C16, C18, C20, C22, C24, C27, C30, C35, C40, C45 and C50, and for hardwood: D30, D35, D40, D50, D60 and D70. Poplar wood is treated as coniferous, thus, it is placed into the C classes. This standard also defines the characteristic values of strength properties, elastic properties and density of wood for each C and D class. Characteristic values of strength properties for several selected strength C classes (lowest: C14, highest C50 and C18, C24 and C30) are presented in table 1. If the board is qualified as a given C class, it is assumed that it meets the minimum values of strength and stiffness properties as well as density. If the designer of a wooden roof truss knows, for example, the strength class of timber (e.g. C24), then he has a guarantee that the board has such properties as given in EN 338:2016, i.e. bending strength 24 MPa.

Table 1. Characteristic values of strength properties for selected strength classes of sawn timber (in acc. with EN 338:2016) Strength class (selected) C14 C18 C24 C30 C50 Strength properties [MPa] Bending fmk 14 18 24 30 50 Tension parallel ft,0,k 8 11 14 18 30 Tension perpendicular ft,90,k 0.4 0.5 0.5 0.6 0.6 Compression parallel fc,0,k 16 18 21 23 29 Compression perpendicular fc,90,k 2.0 2.2 2.5 2.7 3.2 Shear fv,k 1.7 2.0 2.5 3.0 3.8 Stiffness properties [MPa] Mean modulus of elasticity parallel E0, mean 7000 9000 11000 12000 16000 5 percentile modulus of elasticity parallel E0.05 4700 6000 7400 8000 10700 Mean modulus of elasticity perpendicular E90, mean 230 300 370 400 530 Mean shear modulus Gmean 440 560 690 750 1000 Density [kg/m3] Characteristic ρk 290 320 350 380 460 Mean Ρmean 350 380 420 460 550

It can be noticed that the number at the C letter in a given strength class corresponds to the bending strength of sawn timber. In practice, in order to qualify the sawn timber for a given C class using sorting machines, its modulus of elasticity and density should be determined. Other characteristic values can be calculated on the basis of mathematical relations and correlations between these parameters. Therefore, modulus of elasticity and density are the key parameters when sorting sawn timber using the machine method. Additionally, they can be determined non-destructively on a full-size sawn timber when using a grading machine. Scaling such a machine, i.e. its release for use, is carried out according to strictly defined procedures and involves examining a certain amount of sawn timber first on a tested machine and then checking the results on the strength testing machine. The results obtained from non-destructive testing are verified by results obtained in traditional, destructive manner of timber testing. After obtaining satisfactory consistency of results, it is assumed that the grading machine is calibrated and can be approved for use (under many additional conditions – see EN 14081-4:2009, in Poland PN-EN 14081-4:2009 Wooden structures – Strength graded structural timber with rectangular cross section – Part 4: Machine grading – Grading machine settings for machine controlled system). In Polish sawmills, the method of visual grading is used almost exclusively. It wasn’t until 2015 when a device for the machine strength grading of sawn timber was installed in the first Polish sawmill – in Tartak Janina i Wacław Witkowscy (Bekas 2016, Krzosek et. all 2015). Another sawmill – Tartak Abramczyk – purchased a machine for the sawn timber strength grading in 2018. According to the research carried out so far, a large share of rejects is obtained during sorting sawn timber when using the visual method, and only a small amount of timber of high strength grade is obtained. With the applying of strength grading by machine method, much more sawn timber of high strength grades is obtained and far less rejects (Diebold 2009, Karlsson 2009). According to research conducted at Faculty of Wood Technology (WULS- SGGW), as a result of visual strength grading up to 52.9% of sawn timber in the tested batch was classified as reject, and only 4.4% to the highest strength grade KW. When sorting the same batch of sawn timber using the MTG device, only 17.5% of the tested batch was classified as a reject (Krzosek 2009). Further studies on pine sawn timber from selected

26 natural forest regions of Poland are currently ongoing at the Faculty of Wood Technology, within the Biostrateg 3 research project,.

RESEARCH MATERIAL The research material consisted of sawn Scots pine (Pinus sylvestris L.) timber from the Silesian Forestry Region in Poland. The sawn timber was cut of raw materials with age classes IV and V, obtained from the young, mixed forest within the Regional National Forest Directorate of Katowice (Olesno Forest Disctrict, Sternalice Forest Subdistrict, forest compartament 14d, geographic coordinates: 50.898629, 18.423915). The timber was dried in industrial conditions in a chamber drier, up to the humidity of ca. 12%, and planed. The nominal dimensions of timber after drying and planing were: 40 x 138 x 3500mm. There were 210 pieces of timber in the batch under research. The timber was prepared at a sawmill in Kalisz Pomorski.

RESEARCH AIM AND SCOPE The aim of research was to verify what the differences are between results of visual (appearance) and machine strength grading. The scope of research included strength grading of sawn timber with both methods.

METHODS Strength grading by visual method was carried out in accordance with PN-D- 94021:2013 Structural sawn timber sorted by strength methods. As a result of the grading, the sawn timber was assigned to sorting classes KW, KS, KG or classified as reject. The results of strength grading are presented in table 2. Strength grading by the machine method was carried out with the use of MTG (Mobile Timber Grader) device from Brookhuis Electronics BV. The dynamic modulus of elasticity is measured by the vibration method which measures the natural frequency of vibration after a short impact. The MTG device has already been used in previous studies conducted at the Faculty of Wood Technology (Krzosek and Grześkiewicz 2008; Krzosek 2009). The results of strength grading with the use of the MTG device are presented in table 3.

RESULTS AND ANALYSIS The results of strength grading results by visual and machine method are presented in table 2 and 3. As a result of sawn timber grading (210 pieces) by the visual method, 41 pieces were assigned to the KW strength grade (19.5% of the whole batch), 24 pieces to KS grade (11.4% of the whole batch), 62 pieces to KG grade (29.5% of the whole batch), whereas 83 pieces (39.5%) were classified as rejects. With reference to the research conducted in previous years, timber originating from the Silesian Forestry Region was characterized by the highest mechanical properties in comparison to the other regions (table 2). Particularly noteworthy is the large share of sawn timber of KW strength class, many times higher than the average share from the previous studies and twice as high as for the best forest region analysed in the previous studies (10.6% for sawn timber from the Baltic Forestry Region). The percentage share of sawn timber in KS strength grade class in the described studies (11.4%) was also higher than the average from previous studies (7.2%). The percentage share of sawn timber in KG strength grade class (29.5%) was lower than the analogous average share obtained in previous studies (35.5%). Rejects in the analysed batch of timber from the Silesian Forestry Region were about 39.5%, its amount was significantly smaller than the average number of rejects found in the earlier studies (52.9%).

Table 2. Results of sawn timber strength grading by visual method in accordance with PN-D-94021:2013 Visual strength grade acc. to PN-D-94021:2013 KW KS KG Reject [no of [%] [no of [%] [no of [%] [no of [%] pieces] pieces] pieces] pieces] 41 19.5 24 11.4 62 29.5 83 39.5

On the basis of the obtained results of visual strength grading, it can be noticed that pine sawn timber from the Silesian Forestry Region has the highest quality in comparison with the five others forest lands analysed in the previous studies at the Faculty of Wood Technology of Warsaw University of Life Sciences – SGGW (Krzosek 2009).

Table 3. Results of strength grading of sawn timber by machine method with the use of MTG device Strength grade acc. to EN 338 C40 C35 C30 C24 C18 Reject [no of [%] [no of [%] [no of [%] [no of [%] [no of [%] [no of [%] pieces] pieces] pieces] pieces] pieces] pieces] 21 10.0 47 22.4 58 27.6 63 30.0 15 7.1 3 1.4

As a result of sawn timber grading by the machine method (MTG), 10% of the batch was in C40 strength class, 22.4% in C35 class, 27.6% in C30 class, 30% in C24 class, 7.1% in C18 class and only 1.4% rejects were noticed. It is worth noting that a large number of sawn timber – 32.4% in total – was assigned to classes that are unachievable at visual strength grading (i.e. C40 and C35). On the basis of the obtained results of machine strength grading, it can be noticed that pine sawn timber from the Silesian Forestry Region has the highest quality in comparison with the five other forest lands analysed in the previous studies at the Faculty of Wood Technology of Warsaw University of Life Sciences – SGGW (Krzosek 2009). A shortcoming of the MTG device is the inability to grade sawn timber with knots occurring on its face side, in cases where an extremely large twist of fibres is present and when planks faces are not precisely cut. In such situations, according to authors’ assumptions, a wave caused by an impact to the board forehead does not reach the other side because of the mentioned defects, neither is it reflected from it nor returns to the vibration detector. In such cases, the MTG device displays the message: ERROR. During the tests described, 3 of a total number of 210 sawn timber boards were not classified into strength grades (1.4% of the batch). Practice indicates that such boards should be described as rejects.

CONCLUSIONS 1. Scots pine sawn timber from the Silesian Forestry Region was characterized by the highest quality, determined both during visual and machine strength grading (KW strength grade 19.5%; C40 and C35 in total 32.4%). 2. The assumption that the machine strength grading results in low share of sawn timber considered as rejects has been confirmed. 3. There are sawn timber elements which were not assigned to any class or marked as rejects during the machine strength grading. Such timber should be classified as rejects based on its visual appearance.

ACKNOWLEDGMENTS: The authors are grateful for the support of the National Centre for Research and Development, Poland, under the “Environment, agriculture and forestry” – BIOSTRATEG strategic R&D programme, agreement No. BIOSTRATEG3/344303/14/NCBR/2018.

REFERENCES

1. ABRAHAMSEN R. B., MALO K. A. 2014: Structural design and assembly of “Treet” – a 14-storey timber residential building in Norway. World Conference of Timber Engineering. Quebec City, Canada, 10–14 August 2014. 2. ABRAHAMSEN R. 2017. MJØSTÅRNET – Construction of an 81 m tall timber building. 23. Internationales Holzbau Forum IHF 2017. Garmisch, Germany, 6–8 December 2017. 3. BEKAS J. 2016: Services on the first line of machine timber grading [in polish]. Gazeta Przemysłu Drzewnego, nr 1/2016, pp. 1 and 34–35. 4. BEŚKA M. 2018: Wooden construction industry in Poland [in polish]. Forum Ekologicznego Budownictwa Komunalnego Comunalwood, Gdańsk, 21–22 May 2018. 5. DENZLER J. K., DIEBOLD R., GLOS P. 2005: Machine strength grading – commercially used grading machines – current developments. Proceedings of the 14th International Sympodium on Nondestructive Testing of Wood. University of Applied Science, Eberswalde, May 2–4 2005, pp. 11–16. 6. DIEBOLD R. 2009: Verbesserte Holznutzung durch neuartige maschinelle Festigkeitssortierung. 4 Internationale Kongress der Säge und Holzindustrie. 16–17 Februar, Rosenheim. 7. EN 338:2016 Timber structures – Strength classes. 8. FAST P. 2016: Case Study: An 18-storey tall mass timber hybrid student residence at the University of British Columbia. 22. Internationales Holzbau-Forum IHF2016. 9. GLOS P. 1982: Die Maschinelle Sortierung von Schnittholz. Stand der Technik – Vergleich der Verfahren. Holz-Zentralblatt, No. 13. 10. KARLSSON M. 2009: Maschinelle Festigkeitssortierung mit dem Precigrader. 4 Internationale Kongress der Säge und Holzindustrie. 16–17 Februar, Rosenheim. 11. KRZOSEK S. 1995: Machine strength grading in Germany [in Polish]. Przemysł Drzewny No. 2, pp. 10–12. 12. KRZOSEK S, GRZESKIEWICZ M. 2008: Strength grading Polish grown Pinus Silvestris L. structural timber using Timber Grader MTG and Visual method. Annals of Warsaw University of Life Science – SGGW, Forestry and Wood Technology. No. 66, pp. 26–31 13. KRZOSEK S. 2009: Strength grading of Polish pine timber using various method [in polish]. Publishing by SGGW, Warsaw. 14. KRZOSEK S, BACHER M. 2011: Aktueller Stand der maschinellen Festigkeitssortierung von Schnittholz in Polen und in Europa. Annals of Warsaw University of Life Science – SGGW. Forestry and Wood Technology, No. 74, pp. 254–259. 15. KRZOSEK S., MAŃKOWSKI P., WITKOWSKI P., 2015: Maschinelle Festigkeitssortierung erstmals in polnischem Sägewerk. Annals of Warsaw University of Life Sciences – SGGW. Forestry and Wood Technology. No. 89 pp. 83–88. 16. PN-EN 14081-4: 2009 Wooden structures – Strength graded structural timber with rectangular cross section – Part 4: Machine grading – Grading machine settings for a machine-controlled system. 17. PN-D-94021:2013 Conifer constructional timber graded with strength methods.

Streszczenie: Porównanie wyników wizualnego i maszynowego sortowania wytrzymałościowego tarcicy sosnowej ze Śląskiej Krainy Przyrodniczo Leśnej. Praca dotyczy

29 analizy wyników sortowania wytrzymałościowego drewna sosny zwyczajnej dwoma metodami – wizualną oraz maszynową, przeprowadzonego dla surowca pozyskanego ze Śląskiej Krainy Przyrodniczo Leśnej. Sortowanie wytrzymałościowe metodą wizualną przeprowadzono zgodnie z PN-D-94021:2013, natomiast sortowanie metodą maszynową przy użyciu urządzenia MTG holenderskiej firmy Brookhuis Electronics BV. W wyniku przeprowadzonych badań potwierdzono prawidłowość, że przy sortowaniu maszynowym otrzymuje się bardzo małą liczbę sztuk tarcicy zaliczoną do odrzutów. Jednocześnie w trakcie badań zdarzyły się sztuki tarcicy, które przy sortowaniu maszynowym nie zostały zaliczone do żadnej klasy ani do odrzutów. Taką tarcicę na podstawie jej wyglądu należy zakwalifikować, jako odrzut.

Corresponding author:

Slawomir Krzosek 159 Nowoursynowska St., B. 34 email: [email protected] phone: +48 22 59 38633

ORCID ID: Krzosek Sławomir 0000-0001-5212-4126 Burawska-Kupniewska Izabela 0000-0001-8636-5622 Mańkowski Piotr 0000-0003-4459-5029 Grześkiewicz Marek 0000-0003-1504-2062

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 31-36 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

COMPRESSIVE RESISTANCE OF THE MYCELIUM COMPOSITE

ZUZANA VIDHOLDOVÁ, DOMINIKA KORMÚTHOVÁ, JÁN IŽDINSKÝ, RASTISLAV LAGAŇA Faculty of Wood Science and Technology, Technical University in Zvolen

Abstract: Compressive resistance of the mycelium composite. Mycelium composites are a type of novel, economical and environmentally sustainable materials. The advantage of this material is that it forms a compact unit without the use of any adhesives. In this study mycelium boards were prepared from middle wood chipped particles for the manufacturing of commercial particle boards by using the growth activity of fungus Trametes versicolor. The compressive resistance of the mycelium composite was low but acceptable and comparable with other materials.

Keywords: mycelium composite, compressive resistance, Trametes versicolor

INTRODUCTION About 30 million tons of wood waste is generated each year in the countries of the European Union. Much of the wood waste comes from the household (furniture, doors, windows, floors and the like) and production residues from wood industries (sawdust, sawmill particles, wastes from panel edging, particles). A very large fraction of waste wood still ends up in landfills or is widely recognized feedstock for wood-based composite (Merl et al. 2007, Dodoo et al. 2014, Laskowska–Mamiński 2018). This large volume of wood waste has new business opportunities and new markets through various projects, which makes a range of materials with low carbon footprint and economically competitive over the past decades available to companies. In recent decades, new ecological and environmentally suitable materials made of wood or other organic substrates, colonized by mycelium have been developed as novel bio- based materials. Mycelium composites are made-up by inoculating an individual strain of fungi (hyphae) in a substrate of organic substances (Bayer et al 2011, Holt et al. 2012). Hyphal network (mycelium) degrades and colonizes the substrate, using the products of degradation as feeding elements to extend its hyphae from the tip. On the other hand, the mycelium branches new hyphae and fuses them together forming a denser network. Like a self-assembling biological binder, mycelium glues the substrate and provides its strength and integrity. Suitable media for a substrate can be retrieved from agriculture, like wheat or rice straw or husk, wheat grain (Ziegler et al. 2016, Jones et al. 2018), cotton carpel (Holt et al. 2012), corn stover (Tudryn et al. 2018), from waste wood chips (Yang et al. 2017) or from other natural fibres such as jute, flax, hemp, burlap, etc. (Lelivelt et al. 2015). What significantly influences the final properties of the resulting material is the type of chosen organic substrates, and how they are created. A bio-composite consisting of mycelium-plant material can be applied as a biodegradable alternative for a wide range of industrial materials as a replacement for non-renewable resource materials such as polystyrene, styrofoam or poly-urethane foams (Attias et al. 2017). There are different applications of the mycelium composite, such as:  mycelium foams, which are created by baking the inoculated substrate to render the mycelium inactive (Bayer – McIntyne 2011, Holt et al. 2012, Pelletier et al. 2013, Yang et al. 2017). This material is usually used as a packaging material or as low density boards which are biodegradable, fire proof and water resistant;

 mycelium bricks, which are created by mechanically pressing the inoculated substrate at least once during the growing process in a rectangular form. When pressure is applied, the bonding becomes stronger between the secondary materials and the fungal mycelium, thus the material has higher density, and compressive and flexural strength (Ross 2016);  mycelium boards – are created by pressing the inoculated substrate or low density boards under heat and high compressive pressure to achieve the desired densities (Pelletier et al. 2017). The mycelium particleboard, branded MycoBoardTM, has application in work surfaces, moulded furniture components, seatbacks, architectural panels, door cores and cabinetry. It offers an environmentally sustainable alternative to particle board, plywood, and fibreboard traditionally produced from pressed and extruded wood chips and synthetic resin;  mycelium sandwich panels – are fabricated using (epoxy) resin to adhere a mycology matrix core material to a top layer (a carbon fibre woven textiles layer, a laminate layer, etc.) (Travagliny et al. 2014, Jiang et al. 2016, Yang et al. 2017).  grow it yourself (GIY) – Ecovative are selling bags of dehydrated mycelium inoculated substrate. Dry conditions reserve the mycelium in hibernation and it is reactivated by adding water and flour to the bags. The reactivated mycelium can be placed in custom shaped forms prepared by the user (Ecovative GIY, 2018). This study aims to characterize the compressive resistance of mycelium composite prepared in laboratory conditions and compare it with low density particleboards.

MATERIALS Two sets of samples were made (Figure 1). The first set consisted of low density mycelium boards (MBs) consisting of mycelium of fungus Trametes versicolor, and the second set consisted of low density particleboards (PBs). The applied substrates consisted of industrially produces spruce wood particles intended for the core layer in the production of OSB boards. The portion and size distribution of particles in substrates can be found in Table 1. Further, the MBs substrate contained wheat flour in the amount of 4 % wt. (weight of flour per weight of wood particles), mycelium of Trametes versicolor on malt agar plates (170 cm2 for 100 g of the substrate) and demineralised water (30 ml for 100 g of the substrate). The special PBs with low density were prepared from same particles with average moisture content 3.7 ± 0.17%, urea-formaldehyde glue (solids 66%) in amount of 8% wt. (absolute dry weight of UF per weight of absolute dry particles), ammonium nitrate as hardener in amount of 4% wt. (weight of hardener per used weight of UF), and paraffin emulsion in amount of 1% wt. (absolute dry weight of paraffin emulsion per weight absolute dry particles).

Table 1. Overview of wood substrate – the size and portion distribution of wood particles. Spruce wood particles The portion of particles fractions in substrate [%] Size [mm] 20 11.2 4 1.6 1.25 0.8 0.5 0.25 fines Low density MBs 6.03 13.59 40.68 24.95 4.84 6.11 2.84 0.60 0.36 Low density PBs 0.94 10.5 54.7 24.42 3.72 3.84 1.32 0.4 0.16 Note: Substrate weight (before the test analyse of the portion and size distribution of particles) = 100 g.

METHODS OF FABRICATION OF THE BOARDS Fabrication of the MBs (Figure 2A) – The substrate was sterilized by placing it in autoclave at temperature of 121°C and pressure 1.25 kPa for 60 minutes. After cooling, the substrate was mixed with flour, water and fungal mycelium. The substrate was then placed

32 into Petri dishes with diameter 180 mm and the nominal thickness of 30 mm. The Petri dishes were closed and then placed in a climatic camber. The samples were allowed to grow in dark conditions, during 21 days, at the constant temperature of 30 ± 2°C. After the growth period, the samples were placed inside a room and subsequently in an oven at 60°C and dried for 8 hours. 5 low density MBs were prepared in total. Fabrication of the PBs (Figure 2B) – The 1-layer PBs with the area size of 250 mm × 180 mm and the nominal thickness of 25.0 mm were prepared in laboratory conditions. The application of a mixture of urea-formaldehyde glue, hardener and paraffin emulsion on wood chipped particles was performed in a laboratory rotary mixing device. The wood particles were coated with glues, then loaded into a pre-pressing form, and finally pressed in a laboratory press. The pressing process was performed in accordance with the three stages pressing diagram (Figure 1) at the maximum specific pressure of 4.5 MPa, a temperature of 210°C, and a pressing factor of 12 s. In total, 6 low densities PBs were prepared.

Figure 1. Three stages of pressing diagram

A) B) Figure 2. Mycelium board (A) and low density particle board (B)

COMPRESSIVE TESTS Measuring compressive properties of the prepared boards was done in accordance with the standard ASTM C 165-07. Strength was defined as the stress at a 20% deformation. Both groups of samples were tested using a FPZ 100/1 machine at a 9.41 mm.min-1 load speed. The compressive resistance was calculated as follows:

S = W/A (1) where: S – compressive resistance [Pa], W – load at 20% deformation [N], A – average original area of tested sample.

RESULTS Figure 3 reported compression curves in which the load increased exponentially with deformation. The initial slope was evidently higher for PBs than MBs. An actual point of stress at a 20% deformation was reached in a 5–6 mm displacement equal to 20% of the depth of the test specimens.

Figure 3. Load-deformation diagram for a mycelium board (MBs) and a low density particle board (PBs)

The average compressive strength of MBs samples at a 20% deformation was 23.95 kPa, which was approximately eight times lower than that of the PBs samples, and approximately four times lower than that of expanded polystyrene (Table 2).

Table 2: A comparison of low density structural materials Material Density [kg/m3] Compressive resistance at a 20% deformation [kPa] Low density MBs 103.0 (0.01) 23.95 (6.79) Low density PBs 189.2 (3.68) 199.0 (73.98) Expanded polystyrene 13.50 – 18.00 96.90 (Vnuk 2017) Note: Standard deviation is in parentheses.

The compressive strength of mycelium composites varies greatly depending on their constituents. Two mycelium composites using the genus Ganoderma achieved very different compressive strength results based on differing substrate materials. Cotton plant-based mycelium composites achieved compressive strengths between 1 and 72 kPa (Holt et al. 2012), while a red oak-based mycelium composite achieved 490 kPa (Travaglini et al. 2013), which was almost seven times stronger. According to Travaglini et al. (2013), the mycelium foam had a compressive strength almost three times the tensile strength. The low density and specific compressive strength make it a sustainable option as the core of sandwich materials. Travaglini et al. (2013) also suggests using it in combination with fibre-reinforced top layers made of eco resins in order to further enhance the ecological message. Another work related to fungal composites (Travaglini et al. 2014) used woodchips as a filler material. This produced composites with flexural strengths of up to 490 kPa and flexural moduli of up to 1300 kPa. While these studies capture the impact of filler materials on the mechanical properties, they do not highlight the impact of the fungal structure on the properties.

CONCLUSSION  Though the observed compressive strength is rather low compared with other materials (PBs, expanded polystyrene), it should be noted that MBs are fully bio-

based, formaldehyde free, compostable and fully degradable. There is a potential for improvement of properties by densification of a mat during preparation of MBs.  Bond strength of mycelial growth would thus appear to be equivalent to that achievable using synthetic resin, since the substitution of these bonding media is the primary difference between mycelium boards and traditional particleboard.

ACKNOWLEDGEMENTS: This work was supported by the Slovak Research and Development Agency under the contract No. APVV-17-0583 and by the Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic for Project VEGA 1/0729/18.

REFERENCES

1. ASTM C 165-07 2017. Standard Test Method for Measuring Compressive Properties of Thermal Insulations. ASTM International, West Conshohocken, PA, 2017, www.astm.org 2. ATTIAS N., DANAI O., EZOV N., TARAZI E., GROBMAN Y. J. 2017: Developing novel applications of mycelium based bio-composite materials for design and architecture. Proceedings of Building with Bio-based Materials: Best practice and Performance Specification, 6th – 7th September 2017, Zagreb, Croatia, 76–77. 3. BAYER E., McINTYRE G. 2011: Method for producing rapidly renewable chitinous material using fungal fruiting bodies and product made thereby. U.S. Patent No. 8,001,719. Washington, DC: U.S. Patent and Trademark Office. 4. DODOO A. GUSTAVSSON L, SATHRE R. 2014: Recycling of lumber. In Worrell E., Reuter M. 2014: Handbook of Recycling - State-of-the-art for Practitioners, Analysts, and Scientists, Elsevier, 151-163. 5. Ecovative GIY 2018. Grow it yourself mushroom material (Instruction Manual). 12 p. https://giy.ecovativedesign.com/wp-content/uploads/2014/08/Grow-It-Yourself- Instruction-Manual-v1.0.pdf. 6. HOLT G.A., McINTYRE G., FLAGG D., BAYER E., WANJURA J.D., PELLETIER M.G. 2012: Fungal mycelium and cotton plant materials in the manufacture of biodegradable molded packaging material: evaluation study of select blends of cotton byproducts. J. Bio. Based Mater. Energy 69 (4), 431–439. 7. JIANG L., WALCZYK D., MCINTYRE, G. BUCINELL R. 2016: A new approach to manufacturing biocomposite sandwich structures: Mycelium-based cores. In ASME 2016 11th International Manufacturing Science and Engineering Conference. 8. JONES M., BHAT T., HUYNH T., KANDARE E., YUEN R., WANG C. H., JOHN S. 2018: Waste‐derived low‐cost mycelium composite construction materials with improved fire safety. Fire and Materials, 42(7), 816-825. 9. LASKOWSKA A., MAMIŃSKI M. 2018: Properties of particleboard produced from post-industrial UF-and PF-bonded plywood. European Journal of Wood and Wood Products, 76(2), 427-435. 10. LELIVELT R.J.J., LINDNER G., TEUFFEL P., LAMERS H. 2015: The production process and compressive strength of Mycelium-based materials. In First International Conference on Bio-based Building Materials. 22-25 June 2015, Clermont-Ferrand, France. 1-6. 11. MERL A.D, HUMAR M., OKSTAD T., PICARDO V., RIBEIRO A., STEIERER F. 2007: Amounts of recovered wood in COST E31 countries and Europe. In: Gallis Ch (ed) Management of recovered wood. University Studio Press, Thessaloniki, pp 79– 116.

12. PELLETIER M.G., HOLT G.A., WANJURA J.D., BAYER E., McINTYRE G. 2013: An evaluation study of mycelium based acoustic absorbers grown on agricultural by- product substrates. Ind. Crops Prod., 51: 480–485. 13. PELLETIER M.G., HOLT G.A., WANJURA J.D., LARA A.J., TAPIA-CARILLO A., McINTYRE G., BAYER, E. 2017: An evaluation study of pressure-compressed acoustic absorbers grown on agricultural by-products. Industrial crops and products, 95, 342-347. 14. ROSS P. 2016: Method for producing fungus structures U.S. Patent No. 9,410,116. Washington, DC: U.S. Patent and Trademark Office. 15. TRAVAGLINI S., NOBLE J., ROSS P. G., DHARAN, C.K.H. 2013: Mycology matrix composites. Proc., 28th Annual Technical Conference of the American Society for Composites, 517–535. 16. TRAVAGLINI S., DHARAN C., ROSS P.G. 2014: Mycology matrix sandwich composites flexural characterization. 29th Technical Conference of the American Society for Composites, 1–20. 17. TUDRYN G. J., SMITH, L. C. FREITAG J., BUCINELL R., SCHADLER L. S. 2018: Processing and morphology impacts on mechanical properties of fungal based biopolymer composites. Journal of Polymers and the Environment, 26(4), 1473-1483. 18. YANG Z., ZHANG F., STILL B., WHITE M., AMSTISLAVSKI P. 2017: Physical and mechanical properties of fungal mycelium-based biofoam. Journal of Materials in Civil Engineering, 29(7), 04017030. 19. VNUK R. 2017: The compressibility of insulation for the flat roofs. (Diploma thesis). The Czech Technical University in Prague, Faculty of Civil Engineering. 87 p. 20. ZIEGLER A. R., BAJWA S. G., HOLT G. A., MCINTYRE G., BAJWA D. S. 2016: Evaluation of physico-mechanical properties of mycelium reinforced green biocomposites made from cellulosic fibers. Applied engineering in agriculture, 32(6), 931-938.

Corresponding author:

Technical University in Zvolen Faculty of Wood Sciences and Technology T.G. Masaryka 24 SK-960 01 Zvolen, Slovak Republic E-mail: [email protected] Phone: 00421-45-5206389

ORCID ID: Vidholdova Zuzana 0000-0002-2601-8693

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 37-44 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Corporate social responsibility in woodworking enterprises

KATARZYNA MYDLARZ Department of Law and Enterprise Management in Agribusiness, Faculty of Economics and Social Sciences Poznań University of Life Sciences

Abstract: Corporate social responsibility in woodworking enterprises. Corporate Social Responsibility (CSR) is a concept which in managing an enterprise is based not only on achieving economic effects and generating profit but also takes into account ethical attitude and social needs. Therefore, entrepreneurs are expected to take actions that will also be visible in a different area than the commercial one. The concept of CSR may be applied in enterprises belonging to all industries, regardless of the form of business activity, income or employment. The aim of the article is to show a new direction for the functioning of companies in relation to the wood sector, indicate companies using the CSR principle in their activities, assess the extent to which CSR is used by enterprises in the wood industry, and also indicate the relationship between these activities and the high position of companies in the sector. The article lists the enterprises of the wood industry which introduced CSR assumptions to the strategic goals of their activity.

Keywords: Corporate Social Responsibility (CSR), sustainable development, wood companies

INTRODUCTION According to the Corporate Social Responsibility (CSR) concept, businesses should address social interests, environmental protection concerns and relationships with various stakeholder groups when building their strategy (Tylec A. 2016). The essence of CSR was identified by the International Organization for Standardization (ISO) which published the ISO 26000 Guidance on social responsibility, one of the key standards in this area, on 1 November 2010. The standard is among the three documents recommended by the European Commission to be used by European enterprises for the purposes of CSR implementation. “ISO 26000 provides guidelines for social responsibility defined as the responsibility of an organization for the impacts of its decisions and activities on society and the environment through transparent and ethical behaviour.” In Poland, it was published as PN-ISO 26000:2012 “Guidelines for social responsibility” on 5 November 2012. (PN-ISO 26000:2012: Wytyczne dotyczące społecznej odpowiedzialności (Guidelines for social responsibility, www.pkn.pl). Note, however, that unlike other standards, ISO 26000 is neither a certification nor a compulsory standard. Instead, it only enables a closer look at specific values and provides CSR guidance. Despite the fact that CSR principles are not obligatory for enterprises, in 2014 the European Union introduced a directive concerning CSR reporting, where for the first time there was any information about its voluntariness. On the contrary, the directive shows that “Large undertakings which are public-interest entities exceeding on their balance sheet dates the criterion of the average number of 500 employees during the financial year shall include in the management report a non-financial statement…”. The information is to cover “environmental, social and employee matters, respect for human rights, anti-corruption and bribery matters”. (Dyrektywa Parlamentu Europejskiego i Rady 2014/95/UE z dnia 22 października 2014 r., https://eur-lex.europa.eu/eli/dir/2014/95/oj). This directive came into force in Poland in 2018. It was introduced into the Polish law in the form of the Accounting Act, thanks to which the importance of non-financial reporting increased significantly (Raport Odpowiedzialny Biznes w Polsce; Dobre praktyki 2018 – Report Responsible Business in Poland; Good Practices 2018, (http://odpowiedzialnybiznes.pl/wpcontent/uploads/2019/04/Raport2018.pdf).

Information on corporate social responsibility may also be found in the Europe 2020 Strategy which requires the European Commission to take measures to ensure long-term employee and consumer trust in CSR-compliant businesses (A. Makarewicz-Marcinkiewicz 2014, Europe 2020: A strategy for smart, sustainable and inclusive growth. Brussels, 2010, pp. 11–22, http://ec.europa.eu/eu2020/pdf/1_PL_ACT_part1_v1.pdf). The relevant assumptions and measures of CSR were also defined by the European Union in the Green Paper. That definition became a source of guidelines and a reference point for those involved (Żychlewicz M. 2015). In the CSR concept, the guideline for social responsibility and sustainable development policies is to create a shared value and, as a consequence, to plan and take responsible actions. CSR is based on consistency between operating methods and reasons behind business operations. Any CSR-compliant actions and investments should be aligned with the corporate strategy. Rather than single gestures, these should be long-run systemic measures which ultimately contribute to social transformation (Zrównoważony rozwój 2018).

POSITION OF THE WOOD INDUSTRY IN THE POLISH ECONOMY Corporate social responsibility is applied in many enterprises of various industries, including the wood industry, which plays a significant role in the Polish economy. This industry generates about 2% of GDP and sells abroad about 45 billion PLN worth of products annually, which is about 10% of the total Polish export (www.lasy.gov.pl).

LOCAL Round wood suppliers: forests COMMUNITY CUSTOMERS Suppliers of lumber and primary processed timber: sawmills LOCAL AUTHORITIES Suppliers of final products: manufacturers SUPPLIE of furniture, woodwork, wood-based RS CENTRAL products, cardboard and paper GOVERNMENT STAKEHOLD ERS EMPLOYEES MEDIA

Buyers of round wood: sawmills; COMPETITORS manufacturers of wood panels, cardboard OORS RECIPIEN TTTTSTT and paper STOCK EXCHANGE Buyers of lumber and primary processed TTTTS timber: furniture producers, building depots, wooden house producers UNION INSTITUTIONS Buyers of final products: warehouses, stores, individual customers

Figure 1. Key stakeholder groups of the timber industry (Own study)

The importance of the wood industry for the economy is also evidenced by the report of the Ministry of Entrepreneurship and Technology, according to which the highest net trade volume was recorded for the following commodities in 2017: 1. furniture (EUR 7.7 billion) 2. vehicles, vehicle parts and accessories (EUR 4.3 billion) 3. meat and edible offal (EUR 3 billion) 4. wood and wood-based products (EUR 2.6 billion)

5. tobacco and processed tobacco substitutes (EUR 2.2 billion) (www.wnp.pl, an economic site). This data confirms the important role and a strong position of the timber industry in the national economy. Therefore, any measures taken to integrate the aspects of sustainable development (including corporate social responsibility principles) in business operations are and will be clearly visible in key reports and rankings. In the case of many companies mainly known for their extraordinary financial performance, the implementation of CSR assumptions may contribute to a new corporate image. This is especially true for large enterprises because they are the ones able to establish the lines of action for smaller companies (who very often take the strategic industry leaders as a benchmark).

Table 1. Wood industry companies from Poland and other countries of Central and Eastern Europe, which were included in the Coface ranking list. Polish timber companies included in the ranking

No Rank Company name Industry 2016 sales Sales 2016 profit Profit turnover turnover [EUR growth [EUR growth rate million] rate million] 1. 67 PAŃSTWOWE Wood and 1,825 2.8% 92 5.7% GOSPODARSTWO LEŚNE furniture LASY PAŃSTWOWE 2. 165 IKEA INDUSTRY Wood and 998 -2.4% 28 13.2% POLAND SP. Z O.O. furniture

3. 178 PFLEIDERER GROUP S.A. Wood and 930 162.0% 15 -42.0% furniture 4. 249 IKEA RETAIL SP. Z O.O. Furniture 730 17.8% N/A N/A 5. ARCTIC PAPER S.A. Paper, 673 2.3% 14 329.7% 276 packaging and

printing 6. 294 MONDI ŚWIECIE S.A. Paper, 638 0.0% 108 -13.8% packaging and printing 7. 340 INTERNATIONAL Paper, 551 6.4% 100 19.6% PAPER-KWIDZYN SP. Z packaging and O.O. printing

8. 409 SWISS KRONO SP. Z O.O. Wood and 459 5.2% 49 12.7% furniture 9. 482 KRONOSPAN Wood and 399 -1.6% 11 238.7% SZCZECINEK SP. Z O.O. furniture

Other Central and Eastern European timber companies included in the ranking No Rank Company name Industry 2016 sales Sales 2016 profit Profit turnover turnover [EUR growth [EUR growth rate million] rate million] 1. 358 MONDI SCP, A.S. (SK) Paper, 525 1.5% N/A N/A packaging and

printing 2. 390 IKEA COMPONENTS Non- 489 3.9% 5 262.8% S.R.O. (SK) specialized

trade 3. 446 HOLZINDUSTRIE Wood and 429 -1.8% 42 -8.1% SCHWEIGHOFER SRL furniture

(RO) 4. 477 LESY ČESKÉ Wood and 403 -5.2% 154 -22.9% REPUBLIKY, S.P. (CZ) furniture Source: own study based on www.coface.pl.

The company’s image is shaped also by stakeholder groups, i.e. entities who have an impact on, and are impacted by, the company. In addition to external parties, i.e. customers, investors, suppliers, competitors and institutions, this group includes the employees. The key stakeholders of the timber industry are shown in Diagram 1. Each stakeholder will have a different impact on the company and other issues will be relevant to the company. What mostly matters to external parties is credibility, timeliness and efforts made to keep the company financially sound. In turn, the employees are interested in guaranteed employment and remuneration levels. All of these factors affect the quality of work and involvement of individuals; by providing a sense of security, they also have an impact on efficiency improvements.

MATERIAL AND METHODS Below is a list of largest top-ranked timber companies identified based on desk research and web research. The rankings covered by this analysis include: - TOP 500 CEE 2017, a ranking by Coface (an international receivables insurance and business intelligence company), listing the 500 largest Central and Eastern European companies with the highest sales turnover in 2016 (table1): - the 2017 Forbes ranking of the 100 largest Polish private companies (table 2):

Table 2. Wood industry companies from Poland which were included in the Forbes ranking list No. Rank Company name Value of the company (PLN million) 1. 21 Fabryki Mebli Forte 2,079 2. 34 Agata Meble 1,450 3. 42 Black Red White 1,331 4. 50 Paged 1,235 Source: own study based on www.forbes.pl.

- the 2017 Wprost ranking of the 200 largest Polish companies (table 3):

Table 3. Wood industry companies from Poland which were included in the Wprost ranking list No Rank Previous Company name Industry 2016 sales 2015 sales Revenue year rank figures figures (PLN growth rate (PLN million) (%) million) 1. 80 69 Black Red White Wood industry, 1,719 1,663 3.39% SA furniture making 2. 92 95 Grupa Nowy Styl Wood industry, 1,384 1,203 15.05% Sp. z o.o. furniture making 3. 107 113 Agata SA Trade (furniture) 1,170 998 17.28% 4. 114 116 Fabryka Mebli Wood industry, 1,090 954 14.22% Forte SA furniture making 5. 146 143 Grupa Meblowa Wood industry, 796 777 2.39% Szynaka furniture making 6. 147 133 Paged SA Wood industry, 787 756 4.1% furniture making, plywood production, trade 7. 153 171 Drutex SA Window 733 620 18.18% manufacturer 8. 186 183 Stelmet SA Wood and paper 567 554 2.35% industry 9. 194 192 TFP Sp. z o.o. Wood and paper 537 536 0.19% industry 10 196 - Dajar Sp. z o.o. Furniture 516 451 14.41% manufacturer

Source: own study based on www.rankingi.wprost.pl

The analysis of CSR reports from the years 2010–2017 was also made; it listed the key companies from the wood industry introducing CSR assumptions in practice. The list of these companies is given in Table 4.

Table 4. Wood industry companies from Poland, which were included in CSR reports No. Year Number of Thematic area Companies practices in the year concerned 1. 2010 1 Social inclusion and development of local IKEA Retail communities 2. 2011 7 Social inclusion, development of local IKEA Retail, Antalis Poland communities, environment 3. 2012 7 Environment, social inclusion, development of IKEA Retail, Antalis Poland local communities, governance 4. 2013 14 Governance, social inclusion, development of local Panas Schody, IKEA Retail, communities, environment Kronopol, Nowy Styl 5. 2014 12 Social inclusion, development of local IKEA Retail, Kronopol, Nowy Styl communities, environment, consumer issues, governance 6. 2015 14 Environment, social inclusion, development of IKEA Retail, Grupa Nowy Styl, local communities, labour practices, fair Antalis Poland, Porta KMI Poland operational practices, consumer issues 7. 2016 8 Labour practices, social inclusion and development IKEA Retail, Grupa Nowy Styl, of local communities Antalis Poland 8. 2017 15 Social inclusion, development of local IKEA Retail, Grupa Nowy Styl, communities, environment, labour practices Antalis Poland Source: own study based on www.odpowiedzialnybiznes.pl

An analysis of CSR implementation was performed for timber companies listed in the rankings. This became the basis for indicating the major orientations and methods of corporate social responsibility which are being put into practice.

RESULTS AND DISCUSSION As shown by the analysis of social reports and of the Responsible Business report, social practices implemented by the companies are usually related to their activity. Wood companies take measures related to environmental awareness, forest protection and importance of the forests for humans. Table 5 shows a summary of CSR solutions used by wood producers listed in the ranking. It suggests that all measures covered by this analysis are oriented both at the company itself (education and other employee issues, environmental protection in the broad sense) and at the local community. Aspects shared between the two groups are education and environmental protection. In both fields, the objective is to enhance environmental awareness and, as a consequence, to take measures which, on the one hand, provide business benefits and contribute to optimizing of the production processes run by the companies and, on the other hand, provide guidelines for daily activities and decisions made by the community. Examples of CSR measures taken by timber companies include participation in social programs and support for people and organizations who find themselves in difficult circumstances due to accidental causes. Usually, the support consists in providing the disadvantaged population with company products, i.e. furniture, woodwork, floors etc. Such actions are often taken in response to the needs expressed by public institutions (e.g. schools or kindergartens) which, due to budget constraints, are unable to purchase or upgrade their equipment without additional support. As a result of each support activity, the company becomes more widely recognized, which means the outcomes may be very tangible. With a positive feedback from the public, corporate social activities may result in increased sales of company products. Seeing the

41 involvement of specific companies, the public is likely to show increased interest in their products because: - the company concerned becomes more widely recognized in the market and enjoys brand recognition, and - the company’s social activities are socially accepted, and therefore the public want to identify with the company by supporting its actions and choosing its products.

Table 5. CSR solutions used by timber producers. Environment Employees - planting trees distributed by the producers to - travels, holiday camps, domestic and international customers who purchased wood products trips for employees and their families - energy production from biomass - organization of meetings and workshops with - use of state-of-the-art technologies famous people representing the arts, culture, business - promotion of environmentally-friendly attitudes and and sports involvement in environmental protection projects - organization and co-organization of festivals - educational and environmental classes in company- - company-based kindergartens and crèches based kindergartens - football, volleyball, angling and blowing clubs, - waste segregation and delivery to operators who organization of yacht racing events will first have it recovered and recycled - monitoring of wastewater quality and of dust and gas emissions - optimization of production and packaging processes - minimizing the use of paper (double-sided printing, electronic document flow), toner recycling Education Society - organizing workshops and training sessions to - support for organizations with a public-benefit develop specialist and language skills and to support status the personal development of employees - helping people who find themselves in difficult - educational projects which include post-graduate circumstances, having lost all their possessions due to courses and development programs for managers, accidental causes specialists and production workers - scholarships for talented youth - financing for employees who enrol in university - support for social projects which activate local courses to enhance their knowledge and improve communities, promote integration and contribute to their skills as part of their professional tasks an improvement in living standards - cooperation with universities and high schools: - expansion of the infrastructure serving the local apprenticeships and internships for the students community Source: own study based on data delivered by companies listed in the rankings Coface, Forbes, Wprost, Odpowiedzialny Biznes.

In both cases, the product price is a secondary concern for a well-informed customer. Customers very often decide to pay more for a product because they know this is how they support and participate in the company’s social actions, even if they do so indirectly. Therefore, by engaging in social projects and incurring the costs involved in CSR measures, the producer may become more widely recognized while also boosting its sales figures. Therefore, social activities may provide economic benefits to the company. Note that the company’s CSR offering should be adapted to the needs of the local community, and should address the problems faced by the residents. Therefore, it is important to listen to those directly involved. For the company, this is the only way to provide true support and to earn positive feedback from the local community. CSR is not only about providing support which may be demonstrated by the company; it is about providing targeted assistance to people and organizations in need.

CONCLUSIONS In Poland, the CSR concept is used increasingly often in enterprise strategy planning and implementation. The growing interest in CSR among Polish operators is evidenced by many developments, including the increased number of companies who present their achievements in the “Responsible Business in Poland,” a yearly report by the Responsible Business Forum. It is also influenced by changing legal regulations in this area. Some Polish companies do not care for the social aspect of sustainable development because they enjoy a well-established brand and have a stable position. They often focus on short-term objectives without thinking of the future consequences of their decisions. However, there are other businesses who consider CSR compliance to be a priority. Wood companies analyzed in this paper are among those that, while being well-established and recognizable, meet the challenges posed by CSR. Their activities are beneficial not only to their employees but also to the entire local community. Furthermore, according to CSR reports presented by the Responsible Business Forum, more and more wood companies join these efforts. This trend may strengthen the belief that such decisions are driven neither by the company’s standing nor by its financial capacity; they are made by people who profess a philosophy that addresses environmental and social concerns.

REFERENCES

1. Dyrektywa Parlamentu Europejskiego i Rady 2014/95/UE z dnia 22 października 2014 r. ,https://eur-lex.europa.eu/eli/dir/2014/95/oj 2. Europe 2020: A strategy for smart, sustainable and inclusive growth. Brussels, 2010, pp. 11–22, http://ec.europa.eu/eu2020/pdf/1_PL_ACT_part1_v1.pdf [dostęp: 30.04.2018]. 3. MAKAREWICZ-MARCINKIEWICZ A., 2014: Determinanty społecznej polityki zrównoważonego rozwoju (Determinants of a social policy of sustainable development). AR PRODRUK Poznań 2014, pp. 67–74). 4. PN-ISO 26000:2012: Wytyczne dotyczące społecznej odpowiedzialności (Guidelines for social responsibility), www.pkn.pl 5. Portal gospodarczy www.wnp.pl, an economic site 6. Raport Odpowiedzialny Biznes w Polsce; Dobre praktyki 2018 - Report Responsible Business in Poland; Good Practices 2018, http://odpowiedzialnybiznes.pl/wpcontent/uploads/2019/04/Raport2018.pdf 7. TYLEC A., 2016: Społeczna odpowiedzialność biznesu w zarządzaniu przedsiębiorstwami w Polsce (Corporate social responsibility in Polish enterprise management). Scientific Journals of the Silesian University of Technology, Organization and Management series, Journal 97, 2016, https://www.polsl.pl/Wydzialy/ROZ/ZN/Documents/z97/41_po_rec_017_Tylec.p df 8. www.coface.pl 9. www.forbes.pl 10. www.lasy.gov.pl 11. www.odpowiedzialnybiznes.pl 12. www.rankingi.wprost.pl 13. Zrównoważony rozwój – fakty i mity (Sustainable development: facts and myths). Workshop papers, Poznań 2018. 14. ŻYCHLEWICZ M., 2015: Społeczna odpowiedzialność biznesu jako strategia prowadzenia działalności polskich przedsiębiorstw (Corporate social responsibility

as a business strategy for Polish enterprises). Współczesne Problemy Ekonomiczne, No. 11 (2015). Szczecin University, Scientific Journals No. 858.

Streszczenie: Społeczna odpowiedzialność biznesu w przedsiębiorstwach przemysłu drzewnego. W pracy przedstawiono przedsiębiorstwa sektora drzewnego, które w swoich działaniach kierują się zasadą CSR. Zaprezentowano rozwiązania, jakie w ramach CSR stosują wymienione w rankingach firmy. Pokazano kierunek działań dla przedsiębiorców w oparciu o przepisy unijne i zasady społecznej odpowiedzialności biznesu.

Corresponding author:

Katarzyna Mydlarz, ul. Wojska Polskiego 28, 60-637, Poznań, Polska email: [email protected] phone: +48 61 848 74 27

ORCID ID: Mydlarz Katarzyna 0000-0003-0469-5252

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 45-53 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Dual study possibilities in selected EU countries

BEATA FABISIAK1, ANNA JANKOWSKA1, ROBERT KŁOS1 1 Department of Furniture Design, Faculty of Wood Technology, Poznan University of Life Sciences 2 Department of Economics and Economic Policy in Agribusiness, Poznan University of Life Sciences

Abstract: Dual study possibilities in selected EU countries. The idea of dual study courses is more and more common in the EU due to the raising problem of the lack of qualified employees. Although the dual studies are very similar in their form such as internships in companies, case studies etc., their scope differs significantly among the analyzed countries. It was observed that, on average, about 70% of students take part in the vocational education and training in Austria, Croatia, Czech Republic, Finland, Netherlands, Slovakia and Slovenia but only 20% in Cyprus and Hungary. In countries such as: Germany, Netherlands and Austria over 40% of companies employ vocational education and training participants while the average costs of continuing vocational training for the EU-28 is calculated at the level of around 1500 Purchasing Power Standard per participant. The research was based on the data obtained from the EUROSTAT.

Keywords: dual studies, wood technology, higher education, vocational education and training

INTRODUCTION The European labor market suffers greatly from a rapidly growing shortage of leading personnel and skilled workers. The situation is especially visible in small and medium sized enterprises (SMEs) and it can have enormous impact on restriction of their growth. In 2017, the woodworking industry in the EU consisted of 430 000 companies (130 000 dealing with furniture production), with a relatively high number of small or medium-sized enterprises (EUROSTAT 2019). In Poland, there were 26 000 furniture manufacturing companies registered in 2016, 22 000 of them were micro companies. Thus the need for providing well prepared workforce is huge and already well recognized. However the vocational education and training (VET) is often not popular among young people who perceive it as a dead end of professional career, not giving much chances for further academic pathway. This has been observed for many years in various EU countries, including Poland, Latvia or Lithuania where the proportion of young people who decide for vocational training to those who chose studies is about 1/3 to 2/3. The situation looks different in e.g. Germany where a significant number of young entrepreneurs are attracted to vocational training, in particular to the master craftsman training. However, recent developments show that it has been changing to the detriment of VET. Although the master craftsman qualification is classified at the same qualification level of the European Qualification Framework (EQF) as the academic Bachelor’ degree, this does not have any practical effects. It can be observed that the permeability between VET systems and academic education is rather modest. First of all, in many cases the competences acquired in the master craftsman training are not recognized for study programs. Secondly, the master craftsman qualification has a limited international recognition. On the other hand, professionals with master craftsman qualification have practical and theoretical knowledge and skills, enriched with professional experience but they lack competences in business management and leadership to manage a company successfully. In order to successfully run a SME, both practical experience and professional knowledge are essential. Consequently, competences in necessary professional practice and theory as well as professional knowledge should be included in the study programs to cope with the current and future situation on the labor market. In view of the above described conditions, Detyna (2016) wonders whether dual studies are the studies of the future. There is

45 no doubt they are enormously attractive nowadays, however they don’t consist yet of the common form of integrated education. The process of forming the studies into a dual system type aims to support and encourage the transfer of knowledge that is adjusted to the needs of the market. The target map covers the most important practical knowledge required from industrial partners, the methods of ensuring labor supply of each region, and to provide flexible, professional higher education training (Kovacs and Torok 2016).

METHODOLOGY The research shows the characteristics of dual study systems in selected EU countries. The attitude to this kind of educational process, its costs and its meaning in various countries are presented. The selected case studies are described focusing on the range of possibilities and advantages of the systems. The analysis is based on the data obtained from the EUROSTAT.

RESULTS The economy of skill formation shows a specific impact of the dual system of VET on the production model and the development of the welfare state model (Soskice 1999; Culpepper and Finegold 1999; Streeck 1991; Thelen 2004). The research by Busemeyer and Trampusch (2011) on the political economy of collective skill formation follows this approach. It also builds on their earlier research that emphasizes the link between VET and other political-economic institutions, especially labour market institutions. Dual study systems are being introduced in various countries, taking into account varied educational systems, cultural backgrounds, the state of the development of the country’s economy. Those impede educational transactions between developed countries, and are often the source of problems when developing countries try to borrow models, or when they have such models imposed upon them. However we need to be aware of the fact that attempts at borrowing models can fail, both for cultural as well as non-cultural reasons. It concerns also dual study systems. Borrowed models have a greater chance of taking hold if the conditions that forged them are understood, and if the conditions of the receiving country are likewise internalized. Limits imposed by those factors should be recognized (Lewis 2007). This should be an important step to take while preparing integrated European system for the dual studies. Furthermore the study by Zhao (2017) suggests ways in which the dual networks influence various types of knowledge transfer. Both positive and negative effects of recipient and source networks on knowledge that flows into and out of the companies were recognized. The dual networks perspective is particularly relevant for emerging economies where the asymmetry between the knowledge, power and motivations of the recipient and source networks may significantly affect the knowledge transfer outcome. Important inspiration is delivered by Fyle, Moseley and Hayes (2012) through their case studies, illustrating different levels of instructional design in course development for distance learning in a dual-mode institution. It highlights how valuable instructional design can be in forming the future higher education landscape. The German system of skills formation, in particular the dual system of VET, is considered in to be a pillar of the German model for two main reasons: firstly, the training of skilled workers was supported by the specific path of development of diversified quality production from its beginning, and secondly, the dual VET system represents one of the most important fields for the German corporatist governance system. The argumentation results in the following conclusion: the broad trend towards upskilling the German labor force will continue and the integration of low-qualified youth into VET and the labor market will

46 become more precarious than in the past (Baethge and Wolter 2015). For over a century, the development of the general education system was more or less neglected in discussions on VET, for three reasons. First, the Gymnasium track traditionally led to higher education programmes at universities, not to VET programmes (only a small number of students entered dual programmes after leaving the Gymnasium). Secondly, the social background of students in VET and higher education varied and, consequently, there was little competition for educational qualifications. Thirdly, until the second half of the 20th century, educational programmes for craftsmen and skilled workers seemed to focus on basic cognitive skills (reading, mathematics) only, rather than the wider range of cognitive skills emphasized at universities and other types of schools for general education. These conditions fundamentally changed during the second half of the 20th century. In addition, when the dual VET system was dominant and higher education played only a minor role, both sectors co-existed without any problems. However, since the beginning of the 21st century this situation has changed significantly. The quantitative relationship between both sectors is demonstrated by the development in new entrants. Until the mid-1960s, higher education was reserved for a small group of students, in particular from the middle classes. By that time, vocational education was the main pathway into qualified employment for the majority of young people. Then, education reform and educational expansion created new dynamics: by the late 1960s entrants to university – and later to colleges of applied sciences (Fachhochschule) – started to continuously increase, whereas entrants to VET, with some temporary upward and downward turns, continuously decreased. The preliminary end of this development was reached in 2011/2012 when there was an equal number of entrants in both sectors. This quantitative shift in the relationship between the major educational sectors strengthened the discussion on the future of the German skill formation system as a whole: Will the system change towards higher education or will the traditional model of dual vocational education remain the backbone of German industry and the educational model for the majority of employees? A third option would be a new model of skill formation, integrating both systems into a new educational order. The analysis of the share of the students in VET after secondary educational level in the EU counties gives a picture of a diversity of the educational systems. This value varies from about 20% in Cyprus and Hungary to about 70% in Austria, Croatia, Czech Republic, Finland, Netherlands, Slovakia and Slovenia (Figure 1). The question of possible developments of the skill formation systems not only concerns employment and economic growth but also influence social structure and industrial relations. And this process is accompanied by some changes in class structures, especially by the emergence and extension of the social classes of higher – and lower-grade professionals (Erikson and Goldthorpe 1992). While discussing the dual study systems it is also significant to mention the share of EU enterprises providing continuing vocational training (CVT). It gives the picture of the labor market needs in preparation and training of its employees. This value varies among the EU countries from about 20% in Greece and Romania to almost 100% in Sweden and Czech Republic (Figure 2). The importance of CVT is demonstrated by the fact that companies are often able to bear high costs associated with their organization. Analysis of the cost of CVT courses per percipient in different EU countries indicates that they can reach about 3 thousand PPS (Purchasing Power Standard) in countries such as Denmark or Belgium (Figure 3). Percentage of persons employed in enterprises providing CVT courses is very diverse among the EU countries and it ranges from about 30% of employees in Hungary and United Kingdom to 87% in Czech Republic (Figure 4).

Important results are obtained from the analysis of data concerning the number of enterprises employing the participants of VET. The share of them varies significantly among the EU countries. The greatest is in Germany (over 60% of companies) and the lowest in Lithuania (only 1.9%) (Figure 5).

Figure 1. The share of students in vocational education programmes in 2016 (%) (Source: EUROSTAT 2019)

Figure 2. Enterprises providing CVT in 2015 (%) (Source: EUROSTAT 2019)

Figure 3. Cost of CVT courses per participant in 2015 in PPS (Source: EUROSTAT 2019)

Recent studies on new forms of digitalized work (smart factories, Industrie 4.0) confirm the trend towards highly cognitive skills in the field of industrial production work (Hirsch-Kreinsen 2014). Thus educational systems need to follow up to provide the range of necessary skills required by the labour market. Consequently, complementary to the shift in social demand for professional training from vocational to higher education, a new intersection or hybrid sector between both fields has evolved in recent years. The basic ideas behind this development is the implementation of new study models to combine or parallelize vocational training (or work) and studying. Three approaches are worth mentioning here: opening up access to higher education for non-traditional students, the establishment of procedures to recognize vocationally acquired competencies and the considerable extension of dual studies (Baethge and Wolter 2015).

Figure 4. Percentage of persons employed in enterprises providing CVT courses (Source: EUROSTAT 2019)

Figure 5. Enterprises employing VET participants in 2015 (%) (Source: EUROSTAT 2019)

In analyzing the situation of dual study courses in the EU countries it is also crucial to recognize the reasons behind not providing CVT by enterprises (Table 1). In most countries enterprises were indicating the lack of suitable courses in the market and difficulties in assessing enterprise training needs as well as high costs of CVT courses. It’s interesting to note that the reasons – i.e. existing qualifications, skills and competences corresponding to the current needs of the enterprise – reached highest values for France and Slovenia and were indicated by 33.5% and 30% of enterprises, respectively, although they are still at a quite low level. This shows the need for comprehensive and innovative changes in educational systems. In the Hungarian system of higher education, the cooperation between the industry stakeholders and the academic sector is foremost limited to research or performing works based on industry orders. It can have a form of, for example, carrying out investigations in the accredited laboratories owned by universities. Nevertheless, an interesting example and a

49 quite frequent type of cooperation involves company experts in the college final exams. One of the most important reasons encouraging and motivating companies to the long-term investments in higher education institutions is the interest in receiving a steady workforce well prepared for the industry challenges and the needs of the given company. Another issue is also connected to the management of human resources and is about ensuring loyal professionals. During the training, students and business partners are assessed every six months in order to make the training more efficient and target-oriented (Kovacs and Torok 2016).

Table 1. Enterprises not providing CVT by reason for non-provision in 2015 (%) Country Proportion Proportion of non-training enterprises citing selected reasons for not of providing CVT enterprises Existing High Major qualifications, Lack of workload High People Difficult to not CVT skills and suitable and limited costs recruited assess Other efforts competences CVT / no time providing of with the enterprise's reasons made in corresponded to courses available CVT skills training CVT recent the current in the for staff to courses needed needs years needs of the market participate enterprise in CVT Austria 11.9 32.0 12.2 1.6 88.2 10.8 50.0 10.9 44.0 Belgium 16.1 10.7 3.2 2.0 75.5 6.4 28.3 2.5 19.0 Bulgaria 57.8 42.7 21.7 9.5 81.2 21.5 82.8 15.0 39.5 Cyprus 30.5 19.8 7.4 8.7 78.2 13.8 59.7 3.8 34.2 Czech Republic 9.4 5.6 1.0 1.4 69.1 2.3 4.3 . 5.6 Denmark 13.4 22.0 44.0 4.5 73.9 19.5 65.3 38.1 41.9 Estonia 13.9 8.8 1.0 . 43.9 2.3 15.8 . 10.7 Finland 16.9 39.9 36.1 5.1 89.3 14.4 66.2 17.5 48.7 France 21.1 48.3 58.3 33.5 88.5 21.0 63.4 36.8 72.6 Greece 78.3 28.8 16.4 2.7 65.7 13.8 55.5 9.2 42.2 Spain 14.0 38.3 4,2 22.0 84.4 31.2 61.4 20.3 47.7 Netherlands 15.0 14.1 5.9 2.2 73.1 4.4 53.5 3.1 9.5 Croatia 44.6 14.1 4.2 2.2 79.2 7.0 34.5 6.2 12.1 Ireland 22.6 14.8 7.0 3.5 78.6 9.3 51.3 10.3 27.3 Lithuania 38.4 63.7 15.8 12.2 87.4 26.1 85.2 45.5 40.3 Luxembourg 22.9 6.0 4,2 . 70.1 3.5 22.3 . 16.1 Malta 38.4 20.7 6.9 3.8 79.9 8.2 60.9 11.5 39.6 Germany 22.7 23.3 47,1 13.9 87.7 12.2 53.2 23.3 32.4 Poland 55.3 33.7 38.3 16.1 85.2 11.4 70.4 12.1 24.9 Portugal 25.0 46.3 22.3 7.9 76.5 30.3 64.4 30.6 40.5 Romania 73.3 34.0 5.4 5.6 83.5 8.0 78.3 6.7 26.1 Slovakia 30.0 30.6 22.9 15.0 74.2 8.9 48.1 7.9 30.2 Slovenia 15.9 31.3 11.9 30.0 92.0 10.1 64.1 5.5 20.8 Sweden 6.9 ...... Hungary 56.2 30.6 14,2 5.0 85.2 13.4 63.5 10.5 22.7 United Kingdom 14.3 19.1 23.3 13.6 88.7 19.4 73.2 30.8 35.7 Italy 39.8 13.3 8.5 12.1 74.3 6.0 15.4 4.9 14.5 EU-28 27.4 28.2 24.6 13.0 81.8 13.4 54.9 16.2 32.0 Source: Own studies based on the EUROSTAT 2019.

Vocational trainings tend to be understood as a career-focused education that one might traditionally find in a technical college or polytechnic. A very advantageous issue that is incorporated in the dual study courses in various forms – either as semester work or as Engineering Thesis, finalizing the whole educational process at the first level of the higher education studies is the final long-term industry project. During this task, students are expected to deal with the industry based challenge and solve a problem that would add value

50 to the functioning of the company focusing on real conditions and limitations. Students are supervised by experts from the industry and professionals working in academic institutions. Following a professional project management methodology, students undertake an agreed- upon problem and deliver a specific pre-agreed output. Industry partners that hosted these students have said they added significant value to their organizations. In addition, they benefited from the expertise of industry-experienced teaching staff (Lawrence 2017). The necessity of introducing this form of studies in the field of wood technology is demonstrated by the fact that already two initiatives have been organized in this field. The faculty of Wood Technology (at the Poznan University of Life Sciences) introduced this kind of novel study programme implementing the idea of dual studies and a Woodual project which is conducted by the Polish Chamber of Commerce of Furniture Manufacturers. For the Poznan University of Life Sciences it covers the field of mechanical wood technology and chemical wood technology, and the first academic year will start in 2019. Dual studies have numerous advantages: students not only acquire practical experience and skills but also learn about the industry, build their own database of contacts, learn how to solve practical, industry- based problems. Communication skills and the ability to solve actual problems are the values of the future and will be enormously essential when searching for career opportunities. Moreover, students gain the experience not from a single company but rather, during the study process, they may visit and get to know a few of them representing various specializations. This will surely broaden their knowledge and recognition of the industry. The preparation of the dual studies was co-financed by the EU within European Social Fund and carried out under the supervision of the Polish National Centre for Research and Development. During the 3.5 year study course, students will participate in 4 long-term internships in different companies. During the first, third and fifth semester, they will attend classes at the university and acquire the theoretical knowledge, both general academic and specialized. During the second, fourth, sixth and seventh semester, they will perform tasks in the companies and spend much less time having theoretical classes at the university. Furthermore at the last semester of the study course students will prepare an engineering thesis that will be based on a practical, industry-specfic problem. The thesis will be developed with the guidance of a supervisor from the University and a tutor form a company. During the whole study course, there will be study visits organized in the participating companies for all the students (Orlikowska 2018a,b). Similar initiatives are being taken in various EU countries. A valuable example of such activities is the Bachelor & Meister project that aims at developing dual bachelor study courses which combine two degrees – the academic bachelor’s and the vocational master’s degree. This can result in increasing the relevance and quality as well as improving competencies and knowledge in the parts of the vocational master’s program and in the parts of the Bachelor’s degree, transfer the relevant professional skills and practical experience through the dual study approach and realize important contributions to overcoming the shortage of entrepreneurs in SMEs. It can also increase the attractiveness of vocational education and training. The above described initiatives contain important steps towards the contribution to the EU agenda for the modernization of Europe’s higher education systems.

CONCLUSIONS The dual studies in some EU countries have a very long tradition and a wide scope, while in others, they are only at the begging of the road to their popularity. Nonetheless, they are all very similar, indeed. In the examined countries, there is a common practice to do a part of the education process at the universities and the other part in external institutions or companies. Yet, there is still no common regulation indicating and integrating the process of

51 dual studies. In some countries, the practical part of the dual studies is conducted in the form of internships in companies and in the form of case studies to solve industry oriented problems, while in others, it is an advisory system of collaboration between educational and business partners. The analysis of successful stories and further activities towards the development of common system of dual studies should be introduced on the EU level to secure young entrepreneurs in SMEs through innovative educational pathways.

ACKNOWLEDGEMENTS: These examined issues constitute a part of the project: Bachelor & Meister: Designing and implementing a dual Bachelor’s degree study course with integral attainment of a Bachelor’s and Master’s degree. This work was co-funded by the European Union (Programme: Erasmus+, Key Action 2: Cooperation for Innovation and the Exchange of Good Practices). This publication reflects the views of the author only, and the Commission cannot be held responsible for any use which may be made of the information contained therein.

REFERENCES

1. BAETHGE M., WOLTER A., 2015: The German skill formation model in transition: from dual system of VET to higher education? In: The Journal for Labour Market Research, nr.48: pp. 97–112 2. BUSEMEYER M.R., TRAMPUSCH C., 2011: The Political Economy Of Collective Skill Formation. Oxford. 3. CULPEPPER P., FINEGOLD D., 1999: (eds.) German skills machine: Sustaining comparative advantage in a global economy, policies and institutions: Germany, Europe and transatlantic relations. New York. 4. DETYNA B., 2016: Dual Studies as Source of Potential Benefits for Different Stakeholder Groups, Including Development of Entrepreneurial Attitudes and Students Vocational Competences. 5. ERIKSON R., GOLDTHORPE J.H., 1992: The Constant Flux. Clarendon Press, Oxford. 6. EUROSTAT, access date: 24.07.2019. 7. FYLE C., MOSELEY A., HAYES N., 2012: Troubled times: the role of instructional design in a modern dual-mode university?, pp. 53–64 8. HIRSCH-KREINSEN H., 2014: Wandel von Produktionsarbeit – “Industrie 4.0”. Technische Universität, Dortmund, Arbeitspapier Nr. 38 9. KOVACS Z., TOROK E., 2016: Dual System for Renewing Hungarian Higher Education. In: International Journal of Education and Learning Systems, nr. 1; 81-85 10. LAWRENCE A., 2017: Are Vocational and Applied Training the Same Thing in a GCC Context? In: the mismatch between higher education and labour market needs: A Bahrain case study. Oxford Gulf & Arabian Peninsula Studies Forum, 2-5 11. LEWIS T., 2007: The problem of cultural fit – what can we learn from borrowing the German Dual System? In: Compare: A Journal of Comparative and International Education, nr. 37, issue 4; pp. 463–477

12. ORLIKOWSKA K., 2018a: Rozwój i promocja szkolnictwa dualnego ratunkiem dla rynku pracy, Gazeta Przemysłu Drzewnego nr. 6(257); p. 22 13. ORLIKOWSKA K., 2018b: Pierwsze studia dualne na kierunku technologia drewna, Gazeta Przemysłu Drzewnego nr. 12(263); p. 10 14. SOSKICE D., 1999: Divergent Production Regimes: Coordinated and Uncoordinated Market Economies in the 1980s and 1990s. In: Kitschelt H., Lange P., Marks G., Stephens J.D. (Hrsg.) Continuity and Change in Contemporary Capitalism, Cambridge, UK, pp. 101–134. 15. STREECK W., 1991: On the Institutional Conditions of Diversified Quality Production. In: Matzner, E., Streeck, W. (eds.), Beyond Keynesianism, Aldershof, pp. 21–61. 16. THELEN K., 2004: How Institutions Evolve. The Political Economy of Skills in Germany, Britain, the Unites States, and Japan. Cambridge University Press, Cambridge. 17. ZHAO Z., 2017: A Dual Networks Perspective on Inter‐Organizational Transfer of R&D Capabilities: International Joint Ventures in the Chinese Automotive Industry, USA.

Streszczenie: Możliwości studiów dualnych w wybranych krajach UE. Idea studiów dualnych staje się obecnie coraz bardziej popularna przede wszystkim ze względu na problem braku wykwalifikowanych pracowników. Studia dualne są bardzo podobne w swojej formie, uwzględniającej m.in. praktyki w przedsiębiorstwach, studia przypadków itp., jednak ich zakres różni się znacznie w analizowanych krajach. Przeprowadzona analiza wykazała, że średnio około 70% uczniów bierze udział w kształceniu i szkoleniu zawodowym w Austrii, Chorwacji, Czechach, Finlandii, Holandii, Słowacji i Słowenii, ale tylko 20% na Cyprze i Węgrzech. W krajach takich jak: Niemcy, Holandia i Austria ponad 40% firm zatrudnia uczestników kształcenia i szkolenia zawodowego, podczas gdy średnie koszty ustawicznego szkolenia zawodowego dla krajów UE-28 kształtują się na poziomie około 1500 PPS na uczestnika. Analizę przeprowadzono na danych uzyskanych z bazy EUROSTAT.

Corresponding author:

Beata Fabisiak, ul. Wojska Polskiego 28, 60-637, Poznan, Poland email: [email protected] phone: 618487475

ORCID ID: Fabisiak Beata 0000-0002-3279-5632

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 54-59 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019) Evaluation of fungicidal properties of post-cultured liquid medium from the culture of Kombucha microorganisms against selected mold fungi

IZABELA BETLEJ, BOGUSŁAW ANDRES Department of Wood Science and Wood Preservation, Faculty of Wood Technology, University of Life Science

Abstract: Evaluation of fungicidal properties of post-cultured liqiud medium from the culture of Kombucha microorganisms against selected mold fungi. The paper presents the results of the evaluation of fungicidal activity of post-cultured liquid medium from Kombucha microrganism on molds Alternaria alternata and Trichoderma viride. The obtained results confirmed that the medium on which Kombucha microorganisms grew, have fungicidal activity against mold fungi. The lowest concentration of post-cultured liqiud medium, inhibiting the growth of A. alternata and T. viride, on the 4th day of culture, was respectively: 5% and 15%. The total absence of fungal growth was observed on medium containing 20% medium from Kombucha culture.

Keywords: mold fungi, Kombucha, post-cultured liquid medium

INTRODUCTION Wood impregnation with preservatives is currently the only method that guarantees durability of wood in various classes of use. Wood protection products, due to their chemical nature, are subject to strict requirements of law, established in the Regulation of the European Parliament and the Council No. 528/2012 on the provision and use of biocidal products. This regulation imposes on the producers of preparations for wood impregnation ensuring safety for humans, animals and the environment, during the use of impregnants and during the use of impregnated wood. One of the requirements of guaranteed safety is a positive assessment of toxicological reports, ecotoxicological biocides and risk and exposure assessments, which are one of the basic documents guaranteeing obtaining a permit for trade in wood protection products. Due to the fact that many biocides, which until recently placed on the market, were not positively verified, the market for wood protection products narrowed to those where substances that are not potentially hazardous are predominant. With regard to the safety of users of biocides and the environment, more and more studies are undertaken to assess the biocidal effectiveness of substances or chemical compounds of natural origin. Both natural substances such as essential oils, alkaloids, natural resins, but also substances of animal origin or from cultures of microorganisms and even microorganisms are evaluated. Ziglio et al. [1] used an extract of fresh chili peppers to protect pine wood from decomposition caused by Paecilomyces variotii and Pycnoporus sanguineus, while Dasilveri et al. [2] used Acacia mearnsii extract containing tannins as a biocide against Pycnoporus sanguineus, causing white decomposition of wood. Applications of plant alkaloids as potential fungicides have been the subject of research by Cofta et al. [3], while teak extracts to protect pine wood from degradation caused by brown fungus and white decay fungi were subject to analyzes carried out by Brocco et al. [4]. Substances isolated from wood with potential biocidal properties were tested by Nakayama et al. [5], Kirker et al. [6] and Mohammed et al. [7]. The use of metabolites of microorganisms for the biological protection of wood was already undertaken in the 90s of the last century, by Kundzewicz and Ważny [8]. They determined the influence of metabolites synthesized by Trichoderma viride on the growth of selected fungi decomposing the wood. Betlej and Andres [9] evaluated the effect of S. cerevisiae and L. brevis strains as potential biological biocides on the growth of the white fungus Trametes versicolor. Similar studies using microorganisms as biocides were conducted by Bruce [10] and Horvath et al. [11].

S. cerevisiae and L. brevis strains belong to microorganisms belonging to the Kombucha biofilm microflora [12]. Kombucha are symbiotic bacteria and yeasts that carry out acetic fermentation. During the fermentation process, these organisms produce numerous metabolites, including polyphenols, organic acids and ethanol, which are characterized by antimicrobial activity. Pei et al. [13] showed that Lactobacillus plantarum, which is a component of Kombucha microflora, produces bacteriocin, which exerts a bactericidal effect on gram-positive and gram-negative bacteria. The biocidal effects of metabolites from Kombucha culture on selected Candida yeast fungi have been observed by Battikh et al. [14]. The fungicidal effect of metabolites produced by Kombuch against mold fungi found on wood has not been studied so far. This publication presents the results of screening test of influence a post-culture liquid medium from the Kombucha microorganisms on the growth of mold fungi: Trichoderma viride and Alternaria alternata.

MATERIALS AND METHODS Studies on the fungicide effect of post-culture liquid medium obtained from Kombucha biofilm cultures were carried out on selected mold fungus species from the collection of the Department of Wood Science and Wood Preservation: Trichoderma viride, strain A-102 and Alternaria alternata, strain A-166. Kombucha microorganisms (wild strain) also came from the collection of this Department. The microbiological characteristics of microorganisms that are part of the Kombucha biofilm were not analyzed at this stage of the experiment. Kombucha microorganisms were grown on a liquid medium containing the ingredients: mannitol, yeast extract and peptone. The composition of the medium was in accordance with the ATCC instructions for the Gluconacetobacter xylinus strain. The liquid medium from the Kombucha culture was sterilized by means of syringe filters, using filters with a diameter of 0.25μm. The prepared liquid was added to the maltose-agar medium at 0.5, 1, 5, 10, 15, 20 and 30ml, in such a way that the final volume of the medium was 100ml. After thorough mixing of the contents, 10ml of the medium was poured onto Petri dishes, on which mycelium of the molds were centrally grafted. At the same time, control samples were prepared that do not contain liquid medium from the Kombucha microorganism culture. The culture was carried out under temperature - humidity conditions of 22˚C and 65 ± 2%, respectively. The assessment of the influence of medium from Kombucha on the growth of selected mold fungi was based on the measurement of mycelium growth in two perpendicular directions. The colony growth was measured at 48h intervals. Tests were terminated on the day when the substrate was completely covered in the control. Each study was done in triplicate. The results obtained were used to determine the MIC value - the minimum inhibitory concentration inhibiting the growth of microorganisms. To verify statistical hypotheses, analysis of variance for single classification was used, using Snedecor statistics. Statistical inference was carried out for the significance level α = 0.05 and α = 0.01. In the case of rejection of the null hypothesis, the next step was to compare the average test of multiple comparisons - Tukey. Statistical hypothesis: H0: Ø 0.5= Ø 1= Ø 5= Ø 10= Ø 15= Ø 20= Ø 30= Ø K H1: There are at least two averages that differ significantly

RESULTS Analyzing the obtained results, it was found that post-culture medium from Kombucha microorganisms show fungicide properties in relation to the mold fungi used in the studies. It was found that the degree of inhibition of fungal growth was dependent on the proportion of liquid medium in the growth medium. Tables 1 and 2 present the results of the assessment of

55 fungal growth on medium with different content of post-culture medium from Kombucha culture.

Table 1. The diameter of mycelium (A. alternata) growth on medium containing various concentrations of post- culture medium from the Kombucha culture

Variability: diameter of colony Content of Day growth at a given concentration of metabolites in the metabolites culture medium

No. 2 4 6 8 10 Femp F 0,05 Diameter of growth 7099.3 2.41 Division by [ml/100ml] Tukey [mm] Average 1. Control 13.0 37.5 56.5 79.8 90.0 90.0 a 2. 0.5 10.5 35.3 54.3 78.0 90.0 90.0 ab 3. 1 12.8 36.0 53.8 76.0 90.0 90.0 ab 4. 5 9.8 28.5 44.8 64.0 83.5 83.5 c 5. 10 0.0 16.8 26.0 39.7 65.3 65.3 d 6. 15 0.0 0.0 10.5 21.2 40.5 40.5 e 7. 20 0.0 0.0 0.0 0.0 0.0 0.0 f Source: own study.

Table 2. The diameter of mycelium (T. viride) growth on medium containing various concentrations of post- culture medium from the Kombucha culture

Variability: diameter of colony growth at Day Content of metabolites a given concentration of metabolites in the culture medium

L.p. 2 4 6 8 10 Femp F 0.05 Diameter of 839.07 2.39 growth Division by Tukey [ml/100ml] [mm] Average 1. Control 43.3 90.0 - - - 90.0 a 2. 0.5 42.3 90.0 - - - 90.0 ab 3. 1 44.0 90.0 - - - 90.0 abc 4. 5 30.3 90.0 - - - 90.0 abcd 5. 10 15.7 88.3 - - - 88.3 abcd 6. 15 7.0 61.3 - - - 61.3 e 7. 20 0.0 0,0 - - - 0.0 f Source: own study.

The significantly stronger fungicidal activity of post-culture medium from Kombucha microorganisms was observed for the A. alternata fungus. The lowest concentration of medium, inhibiting fungal growth on the second day of culture, was 5%. Complete cultivation of the mycelium medium in the control culture took place on the eighth day of the culture. At the same time, in medium containing 5% of Kombucha culture medium, the diameter of the

56 fungus growth was 83,5mm. At the content of 15% liquid medium, the A. alternata growth diameter was halved compared to the growth in the control sample. At the concentration of 20% post-culture medium, the growth of the fungus was completely inhibited. The influence of liqid medium from Kombucha culture on the growth of T. viride was less intense. At the same time, it was noticed that the growth of the examined fungal species in the control sample was much faster than the growth of A. alternata. On the fourth day of cultivation, mycelium T. viride completely overgrew the control medium. Determined on the fourth day of culture, 10%was the lowest concentration of Kombucha metabolites which inhibited the growth of T. viride. At the content of 20% of liquid medium, the growth of the fungus was completely inhibited.

Figure 1. Percentage of overgrowth of agar-maltose medium with the addition of different concentrations of post-culture medium from Kombucha cultivation by A. alternata mycelium at different times of breeding Source: own study.

Figure 2. Percentage of overgrowth of agar-maltose medium with the addition of different concentrations of post-culture medium from Kombucha cultivation by T. viride mycelium at different times of breeding Source: own study.

A graphical analysis of the percentage of growth of medium containing various concentrations of post-culture liuid medium from Kombucha microorganism’s cultivation by mold fungi is presented in Figures 1 and 2. In the assessment of the medium from Kombucha influence on growth of A. alternata, significant differences were found between the control growth and the test culture containing liquid medium from Kombucha in the amounts from 5 to 20%. However, no significant differences were observed in the growth of the fungus on media containing 0.5 and 1% of Kombucha culture fluid, compared to the control. In the case of the assessment of the increase of liquid medium from the Kombucha culture on the growth of the T. viride fungus,

57 significant differences were found between the control sample and the test sample only in two cases in which the content of post-culture medium in the growth medium was 15 and 20%.

CONCLUSION Analyzing the obtained results, it was found that the post-culture medium from Kombucha microorganisms, show a fungicidal effect on mold fungi used in the presented research. The obtained results are the basis for further analyzes, including: checking what metabolites are produced by Kombucha during their cultivation, what is the composition of microorganisms in the Kombucha biofilm and what will be the effect of this medium on fungi if it is impregnated with wood.

REFERENCES

1. ZIGLIO A.C., SARDELA M.R., GONCALVES D., 2018: Wettability, surface free energy and cellulose crystallinity for pine wood (Pinus sp.) modified with chili pepper extracts as natural preservatives, Cellulose nr. 26; 6151-6160 2. DaSILVERI A.G., SANTINI E.J., KULCZYŃSKI S.M., TREVISAN R., WASTOWSKI A.D., GATTO D.A., 2017: Tannic extract potential as natural wood preservative of Acacia mearnsii, Annals of the Brazilian Academy of Sciences nr. 89(4): 3031-3038 3. COFTA G., WIŚNIEWSKA P.W., PRZYBYŁ A.K., 2014: Środki ochrony drewna – alkaloidy, Aura Ochrona Środowiska nr. 6 (14); 23-24 4. BROCCO V.F., PEAS J.B., Da COSTA L.G., BRAZOLIN S., ARANTES M.D.Ch., 2017: Potential of teak heartwood extracts as a natural wood preservative, Journal of Cleaner Production nr. 142 5. NAKAYAMA F.S., VINYARD S.H., CHOW P., BAJWA D.S., YOUNGQUIST J.A., MUEHL J.H., KRZYSIK A.M., 2001. Guayule as a wood preservative. Industrial Crops and Products nr. 14, 105-111 6. KIRKER G.T.; BLODGETT, A. B.; ARANGO, R. A.; LEBOW, P. K.; CLAUSEN, C. A., 2013: The role of extractives in naturally durable wood species, International Biodeterioration & Biodegradation, nr. 82; 53-58 7. MOHAMMED S.A., MADHAN B., DEMISSIE B.A., VELAPPAN B., TAMIL SELVI, A., 2016: Rumex abyssinicus (mekmeko) Ethiopian plant material for preservation of goat skins: approach for cleaner leather manufacture, Journal of Cleaner Production nr. 133, 1043-1052 8. KUNDZEWICZ A.W., WAŻNY J., 1994: Biologiczna metoda ochrony drewna – wyniki wstępne, [w:] Ochrona drewna – XVII Sympozjum, Wyd. SGGW, Warszawa, 57-63 9. BETLEJ I., ANDRES B., 2018: Microorganisms and their metabolites as potential biopreparation in wood protection, Annals of Warsaw University of Life Science, Foresty and Wood Technology nr 104; 426-431 10. BRUCE A., 2000: Role of VOCs and Rother antagonistic mechanisms In the biological control of wood deterioration fungi by Trichoderma spp. and other antagonists [w:] Ochrona drewna – XX Sympozjum, Wyd. SGGW, Warszawa 19-25. 11. HORVATH E.M., BURGEL J.L., MESSNER K., 1995: The production of soluble antifungal metabolites by the biocontrol funi Trichoderma harzianum in connection with the formation of conidiospores, Material und Organismen nr 29 (1); 1-14 12. VILLARREAL-SOTO S. A., BEAUFORT S., BOUAJILA J., SOUCHARD J.-P., RENARD T., ROLLAN S., TAILLANDIER P., 2019: Impact of fermentation conditions on the production of bioactive compounds with anticancer, anti-

inflammatory and antioxidant properties in kombucha tea extracts, Process Biochemistry nr 83; 44-54 13. PEI J., JIN W., ABD EL-ATY A.M., BARANENKO D. A., GOU X., ZHANG H., GENG J., JIANG L., CHEN D., YUE T., 2019: Isolation, purification, and structural identification of a new bacteriocin made by Lactobacillus plantarum found in conventional kombucha, Food Control, DOI: 10.1016/j.foodcont.2019.106923 14. Battikh H., Bakhrouf A., Ammar E., 2012: Antimicrobial effect of Kombucha analogues, LWT - Food Science and Technology, nr 47; 71-77

Streszczenie: Ocena właściwości fungicydowych podłoża pohodowlanego z hodowli mikroorganizmów Kombucha, w stosunku do wybranych grzybów pleśniowych. W pracy przedstawiono wyniki oceny działania fungicydowego płynu pohodowlanego z hodowli mikroorganizmów Kombucha na grzyby pleśniowe Alternaria alternata i Trichoderma viridie. Uzyskane wyniki potwierdziły, że podłoże pochodzące z hodowli Kombucha wykazuje działanie fungicydowe wobec badanych grzybów pleśni. Najmniejsze stężenie podłoża, hamujące wzrost A. alternata i T. viride, w 4–tej dobie hodowli, wynosiło odpowiednio: 5% i 15%. Całkowity brak wzrostu grzybów zaobserwowano na pożywce, zawierającej w swym składzie 20% płynu pohodowlanego z hodowli Kombucha.

Corresponding author:

Izabela Betlej, ul. Nowoursynowska 159, 02-787 Warszawa email: [email protected]

ORCID ID: Betlej Izabela 0000-0001-6867-0383 Andres Bogusław 0000-0002-1430-6786

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 60-64 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

The grafting of metallocene copolymer to higher polarity with acrylic acid

IGOR NOVÁK1, JURAJ PAVLINEC1, IVAN CHODÁK1, ANGELA KLEINOVÁ1, JOZEF PREŤO2, VLADIMÍR VANKO2 1Polymer Institute Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia 2VIPO a.s., Gen. Svobodu 1069/4, 958 01 Partizánske, Slovakia

Abstract: The grafting of metallocene ethyle-octene copolymer to higher polarity with acrylic acid. Metallocene polyolefins (MePO) were grafted in melt due to increasing their surface free energy and adhesive properties. MePO modification with ozone was used to initiate the creation of peroxides on the surface of the polymer with subsequently grafting of acrylic acid in polymer melt. The efficiency of grafting in melt is high, ranging between 0.77 and 0.97.

Keywords: metallocene polyolefin, ethylene-octene copolymer, acrylic acid grafting

INTRODUCTION Metallocene polyolefins (MePO) represent a sort of polymers with some special properties, i.e. mechanical properties, melting temperature, etc. MePO contain non-polar chains which can interact well with non-polar surfaces (1, 2). Nevertheless, efforts to adjust the hot-melt adhesives (HMA) application parameters, especially regarding increased adhesion to polar surfaces, focus either on basic polyolefin chains polarity increase or on polar polymers addition to the adhesive compositions. The reason is that, owing to their higher surface energy, more polar compositions lead to adhesives with higher adhesive peel and shear strength. An increase of HMA polarity has been frequently achieved by adding polar components to an adhesive polymer composition. An easy way of modifying polyolefin macromolecules by free radical grafting is treating the polymer powder, foils or fabrics by means of polymerizing vinyl monomer along with a free radical initiator (3–7). Such an approach to initiate polymer grafting is used mainly for surface modification of powders, foils and fibres. The method of increasing the polarity of MePO macromolecules by free radical grafting is to treat the polymer powder, foils or fabrics with a polymerizing vinyl monomer along with a free radical initiator. Nevertheless, grafting initiation due to the transfer of the free valence from the polymerizing monomer to the modified polymer represents ineffective process. The ethylene groups in main chain of metalocene copolymer – ethylene-octene copolymer Resinex PE RXP 1502 (RXP) – are tightly bound to the carbon atom and RXP is insufficiently reactive in transfer reactions compared to polymerizing chain grow rate xnt of an unbound homo-polymer formed during grafting process. It is generally accepted that this is the reason causing the low grafting effectiveness. More favourable conditions with higher grafting efficiency exist for metallocene ethylene-polypropylene copolymer (e.g. Licocene) containing hydrogen on tertiary carbon more reactive in transfer reactions (6). The initiation of the graft polymer chains growth on the polymer is the most important reaction for effective binding of polymer branches to the main chain of polymer. The free radical decomposition of hydro peroxide and peroxide groups accumulated on polyolefin molecules is the very effective technique to initiate MePO grafting in high yield. The approach to peroxides accumulation on MePO chain is based on macromolecules oxidation initiated by peroxides, e.g. benzoyl peroxide (BP) (7–9). Oxidation initiated by ozone during polymer treatment in ozone-oxygen mixture considerably accelerates peroxide creation. The polymer oxidation activated with ozone goes over the use of radiation sources applied as

60 initiators in polymer oxidation and this method of polymer initiation with subsequently used grafting is applied for modification of powders, foils and fibres (10–12). In this contribution paper, we are reporting on the experiments consisting in the modification of MePO with the aim to increase of polarity of the polymer. Acrylic acid (AA) was grafted on polymer activated with an oxygen-ozone mixture. The formed graft copolymer was used as an additive to formulate hot-melt adhesive with increased applicability in adhesive properties.

EXPERIMENT In this work, the metallocene ethylene-octene random copolymer Resinex PE RXP 1502 (melting temperature = 70°C, density = 0.874 g.cm-3, tensile stress at yield = 1.76 MPa) was used for HMA preparation in virgin form as the basic component as well as the adhesive additive after modification by grafting. An acrylic acid (AA, Aldrich, Netherlands) monomer, 99% purity, was stabilized with 180–200 ppm of methyl hydroquinone). RXP powder was treated in the flow of O2 + O3 gas produced at a room temperature in an atmospheric plasma generator, power = 300 W (Masaryk University, Czech Republic), input O2 flow = 5L/min. After 3 hours of polymer activation, the concentration of peroxides determined by the volumetric analytical method based on iodine oxidation was (9.1±0.7).10-3 (mol/kg). The modification of the activated RXP powder proceeded in Brabender Plasticorder mixer in 30 mL chamber at 110°C for 30 minutes. Blades revolutions started at 15 rpm, and after 5 minutes they were increased to 30 rpm and followed the step-by-step monomer addition. The samples for analytical procedures were prepared from RXP grafted product by compression-moulding to disks 1mm thick with 20 mm diameter. Press plates temperature was 110°C and moulding time 3 minutes, specific plates pressure 3 N/mm2. The concentration of peroxide groups bonded to RXP was determined by the volumetric analytical method based on iodine oxidation. The procedure was modified for non- aqueous systems. A saturated KI acetic anhydride solution was used as the reagent and the released iodine was determined by titration. The total peroxide oxygen content in RXP sample after 3 hours of oxidation was (9.1±0.7).10-3 (mol/kg). The presence of grafted PAA in RXP-g-AA was proved by FTIR analysis. The spectrometer Nicolet 8700TM in the attenuated total reflectance spectroscopy mood was used. The valence band typical for PE, pertaining to the CH deformation vibrations (region of 2800–3000 cm-1) was observed. Based on contact angle measurements the hydrophilicity changes of RXP-g-AA surfaces were evaluated. The surface energy evaluation (SEE) system with CCD camera, Advex Instruments, Czech Republic) was used for experiments and a sessile drop technique was applied. Deionised water was used as a polar testing liquid. The drops with a volume 20 µl were deposited on a RXP surface and were immediately measured. The SFE of the wood as well as the corresponding polar and dispersive components of the SFE (PC SFE and DC SFE, respectively) were evaluated by the Owens–Wendt–Rabel–Kaelble (OWRK) method modified by incorporating at least squares method [6]. The temperature resistance of the adhesive joints was evaluated by measuring the strength of the adhesive joints in peeling (shear) on the laminated paper with biaxially oriented polypropylene (BOPP) foil used in the packaging industry. The adhesive properties were evaluated by testing the adhesive joints in peel by ASTM-D-4498 (Peel Adhesion Failure Temperature, PAFT) and in shear by ASTM D-4498 (Shear Adhesion Failure Temperature, SAFT) on laminated paper with BOPP foil.

RESULTS AND DISCUSSION The presence of grafted PAA in RXP-g-AA was proved by FTIR analysis. For all samples prepared in this study the valence bands have been observed pertaining to CH deformation vibration (the region of 2800–3000 cm-1), typical for PE. The bands for C-O and COC (1715 and 1170 cm-1, respectively) indicate the presence of PAA chains. The ratio of the FTIR absorbance intensities for acid carbonyl compounds at 1715 cm-1 and the reference band at 1464 cm-1 serves for the PAA concentration determination in grafted copolymer. Changes in FTIR absorbance of these bands in samples 1–3 prepared in polymer melt and with a various amounts of AA are shown in Figure 1.

Figure 1. FTIR spectra of RXP grafted with AA in polymer melt. Sample 1 (9.2% PAA), sample 2 (18.4% PAA) and sample 3 (27.6% PAA) were prepared in a Brabender Plasticoder mixer

The method of increasing the degree of grafting is based on increasing reactants concentration in reaction batches. Although the grafting experiments in solvent indicate low utilization AA to modification RXP, the degree of grafting increases in systems containing a higher monomer concentration (Table 1). An effort to increase the degree of RXP grafting is directed to solvent free reaction. The most important benefit of solvent free reaction conditions is substantial increase in grafting efficiency. The water contact angle (WCA) of initial RXP (106.4o) after grafting by AA decreased (Table 2). This decrease depends on the amount of the grafted AA (RXP with AA 14.1% – WCA = 99o, RXP with AA 26.8% – WCA = 87o). The increase of hydrophilicity of the grafted RXP samples reflects the growth of PC of SFE. For initial RXP, the PC of SFE reached the value 2.3 mJ/m2 and after grafting with AA 14.1% PC of SFE, it increased to 3.6 mJ/m2 and/or 3.9 mJ/m2 (AA 26.8%). The temperature resistance in peel as well as in shear of the adhesives based on RXP polymer is summarized in Table 3. The temperature resistance in peel for unmodified RXP is

PAFT = 64oC, but for RXP-g-AA, the temperature resistance is higher: with AA 14.1% – it is PAFT = 77oC and with AA 26.8% – it is PAFT = 78oC. The values of temperature resistance in shear for unmodified RXP and RXP grafted are similar and no differences were observed.

Table 1. Table 1 presents the batch components concentration and the grafting efficiency for RESINEX PE RXP 1502 grafting in molten state. Polymer was activated 3 hours with ozone-oxygen mixture. The oxidative gas was formed during oxygen flow through an atmospheric plasma generator: power = 300W, gas flow = 5L/min, room temperature. The reaction proceeds in the kneading chamber 30 ml for 30 minutes at 110°C Activated sample 1 sample 2 sample 3 RXP (g) 24.7 22.2 19.7 AA (ml) 2.5 5 7.5 PAA in sample (%) 9.2 18.4 27.6 % Grafted PAA 8.7 14.1 26.8 (% in sample) Grafting Efficiency 0.88 0.77 0.97

Table 2. Contact angles, surface free energies and their polar components of RXP-g-AA films Sample CA water CA GL CA DMSO Total SFE PC SFE -2 -2 (deg) (deg) (deg) (mJ.m ) (mJ.m ) RXP o o o 29.2 2.3 106.4 ± 2.4 101.4 ± 1.4 63.5 ± 2.7 initial 1 o o o 29.8 2.5 105.0 ± 1.8 89.3 ± 3.4 53.2 ± 3.1 AA 8.7% 2 o o o 30.2 3.6 99.0 ± 2.0 88.7 ± 1.7 62.0 ± 1.1 AA 14.1% 3 o o o 30.0 3.8 87.0 ± 3.2 85.7 ± 2.3 66.2 ± 2.8 AA 26.8% 4 o o o 31.8 4.2 77.0 ±2.2 74.7 ± 3.3 48.9 ± 2.8 CRA 9.5% CA = contact angle, GL = glycerin, DMSO = dimethyl sulfoxid, PC and DC of the SFE = polar and dispersion component of the surface free energy.

Table 3. Temperature resistance of adhesive joints using peel (PAFT) and shear (SAFT) tests for RXP-g-AA samples Sample PAA grafted PAFT SAFT (%) (°C) (°C) 1 8.7 75 90 2 14.1 77 92 3 26.8 78 95 RXP initial 0 64 93

CONCLUSION The most effective way in RXP grafting with AA is kneading molten RXP with reaction components in a Brabender Plasticoder. The determined grafting efficiency is high and varies between 0.77 and 0.97. The water contact angle on RXP surface grafted with PAA

63 decreased by at least 15%, or more and the surface energy and its polar component increased 1.1–1.7 times. The temperature resistance in peel of RXP-g-PAA increased 1.3 times, and the values of temperature resistance of adhesive joints in shear are similar.

ACKNOWLEDGEMENT: The authors are grateful for financial support to the Slovak Research and Development Agency projects No. APPV-14-0566 (Slovakia), and also for support by Science Grant Agency VEGA project No. 1/0570/17 (Slovakia).

REFERENCES

1. YALVAC S., KARJALA T., O´BRYAN E. 2005: Adhesives & Sealants Industry, 2005, vol. 12, p. 34. 2. PATEL J. B., EODICE A. K., LOW Y G. 2010: Low application temperature hot melt adhesive. PCT/US 2010/043804 (2010). 3. LAZÁR M., RADO R., PAVLINEC J., 1961: Grafting of methyl methacrylate to polypropylene and polyethylene. Journal of Polymer Science, vol. 53(158), pp. 163– 171. 4. BUCHENSKA J., 2002: Polypropylene fibres grafted with poly(acrylic acid). Journal of Applied Polymer Science, vol. 83(11), pp. 2295–2299. 5. KAUFMAN M. S. 2008: Radical-Mediated Modification of Polyolefins, Thesis, Queen ̛s Univ. Kingston, Ontario, Canada, May 2008, p. 1. 6. NOVÁK, I., POPELKA A., LUYT, A. S. et al., 2013: Adhesive properties of polyester treated by cold plasma in oxygen and nitrogen atmospheres. Surface and Coatings Technology, vol. 235, pp. 407–416. 7. NOVÁK, I., POLLÁK, V., CHODÁK, I., 2006: Study of Surface Properties of Polyolefins Modified by Corona Discharge Plasma. Plasma Processes and Polymers, vol. 3(4-5), pp. 355–364. 8. ZAKI A.J.J.I., 2015: Grafting of polyethylene films with N-vinyl imidazole and acrylic acid for potential use in wastewater treatment. Revue Roumaine de Chimie, vol. 60(9), pp. 867–873. 9. WANG H., BROWN H. R., 2004: UV grafting of methacrylic acid and acrylic acid on high-density polyethylene in different solvents and the wettability of grafted high- density polyethylene. II. Wettability. Journal of Polymer Science Part A: Polymer Chemistry, vol. 42(2), pp. 263–270. 10. STEFFENS G.C.H., NOTHDURFT L., BUSE G., THISSEN H., HŐCKER H., KLEE D. 2002, vol. 23, p. 3523. 11. LAZÁR M., PAVLINEC J., MAŇÁSEK Z., MIČKO M., BEREK D., 1963: Ozonation of Atactic Polypropylene. Rubber Chemistry and Technology, vol. 36(2), pp. 527–531. 12. RICHAUD, E.; FARCAS, F.; FAYOLLE, B.; AUDOUIN, L.; VERDU, J., 2006, Hydroperoxide titration by DSC in thermally oxidized polypropylene. Polymer Testing, vol. 25(6), pp. 829–838.

Corresponding author:

Ing. Igor Novák, PhD. Polymer Institute Slovak Academy of Sciences Dúbravská cesta 9 845 41 Bratislava Slovakia [email protected]

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 65-71 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

The influence of WC grain size on the durability of WCCo cutting edges in the machining of wood-based materials

JOANNA WACHOWICZ, KLAUDIA WIERZBICKA, PAWEŁ CZARNIAK, JACEK WILKOWSKI Department of Mechanical Processing of Wood, Warsaw University of Life Science - SGGW

Abstract: WCCo cemented carbides are one of the basic materials used for tools. They consist of tungsten carbide in 70–96% and a binding warp – cobalt. High hardness of these materials determines their high resistance to abrasive wear. These properties predispose them to be used as a material for cutting tools. This study presents the results of tests on the durability of cutting edges made of WCCo composite of different WC grain in the machining of wood-based materials. The tests showed a several-fold increase of the durability of edges made of WCCo composite of grain size of 0.2÷0.5 µm compared to WCCo blades of WC grain size of 0.5÷0.8 μm and 0.8÷1.3 μm.

Keywords: WC; tungsten carbide; WCCo composite; cutting tools

INTRODUCTION The furniture industry is an important branch of Polish economy system, and furniture is one of the main products exported from Poland. Growing production of furniture, coupled with the technological progress in machining equipment which provides higher and higher machining parameters, generate a demand for new tool materials what will meet higher and higher requirements [1, 2]. 90% of the materials used in furniture industry are wood-based, including: MDF, HDF, particleboard and fibreboard. The multilayer wood-based materials are made of wood particles of different sizes, compressed at a high temperature and pressure using resin, especially urea-formaldehyde, melamine and phenol [3]. Wood-based materials are difficult to machine. They have a heterogeneous structure, a complex chemical composition and structure anisotropy, so, compared to metals, they require different machining techniques [4]. Furthermore, they show low thermal conductivity, which results in significant tool wear. However, accelerated wearing process occurs frequently, especially at high cutting speeds during machining of chipboards containing increased fraction of mineral contaminations in comparison to MDF. Tool wear mechanism consists of two effects, namely: a continuous abrasive wear with superimposed cyclic spalling of edge zone caused by direct contact with hard mineral particles (sand) [5]. WCCo cemented carbides are commonly used tool materials for the machining of wood-based materials. The main component of cemented carbides is WC tungsten carbide. It is characterised by high melting point, increased hardness, high thermal and electrical conductivity and chemical stability at increased temperatures. Thanks to its high bending strength and good wettability with carbides, cobalt is the most common material used as a binder [6, 7]. The size of a WC grain and cobalt content have a crucial impact on edge properties, especially bending strength and hardness [8]. Although carbides have been known for ages, researchers are still trying to improve their cutting properties and durability through, e.g. hard coatings, laser modifications of the outer surface, etc. [9, 10]. Another way of improving tool materials is to develop materials of a submicron and nanometric grain size [11, 12].

MATERIALS Commercial WCCo indexable knives, with dimensions as shown in Figure 1, and WC grain sizes were used to conduct the tests: ultrafine (0.2 <0.5 μm), submicron (0.5 <0.8 μm), fine (0.8 <1, 3 μm). The basic properties of the edge material (given by the manufacturer) are listed in Table 1.

Figure 1. An indexable knife

Table 1. Basic properties of WCCo edges used for the tests Name Co content Density Hardness % wt. g/cm³ HV10 HV30 HRA Ultra Grade 2.4 15.25 2,300 2,200 95.2 Submicron Grade 4.2 15.20 1,920 1,885 93.4 Fine Grade 4.0 14.90 1,790 1,700 92.5

The tool durability was tested using 1000 x 400 x 18 mm particleboard. The basic properties of the board are listed in Table 2.

Table 2. Selected properties of the particleboard used for the tests Material Density Tensile strength Bending Module of [kg/m³] [MPa] strength [MPa] elasticity [MPa] Particleboard, 648 0.41 8.68 2,212 thickness 18 mm

The particleboard milling processes were executed using the BUSELLATO JET 100 machine tool. The tools were tested using a double-edge head. The image of the head and the technical drawing are shown in Figure 2. The spindle rotational speed was 15,000 rpm, feed per tooth: 0.15 mm, feed speed: 4.5 m/min. The wear of the edges was measured each time the board length of 1 m have been milled. The depth of wear was measured using a workshop microscope. The measurement had been taken until the wear value, i.e. the maximum loss of contact surface VBmax was 0.2 mm. The micro-structure of tool fractures was tested using the SEM FEI QUANTA 200 Scanning Electron Microscope.

a) b) Figure 2. Milling head a) — technical drawing, b) image

RESULTS Figure 3 shows a graph of the relation between the VBmax wear value and the cutting length. The edge of carbides of the lower WC grain size (Ultrafine) had the highest durability. The length of cutting route until the edge was blunt (VBmax > 0.2 mm) was 8478 m (27 running metres of the board). The durability of Submicron and Fine edges was twice as small.

Figure 3. A graph of the relation between the wear indicator [mm] and the cutting length [m]

As shown on Figure 3 – the larger the WC grain, the less durable the edges. Edges of 0.2–0.5µm WC grain size were the most durable. Test results show that WCCo edges are worn due to the removal of the cobalt binder in the first place due to the following processes: plastic deformation, micro-abrasion. The removal of the cobalt binder results in the WC grain being crushed and torn off the tool material. Therefore, the smaller the WC grain size and the lower the content of cobalt evenly spread over the borders of WC grains, the higher the wear resistance of the tool. It is also worth noticing that the edges of the smallest grain size also had lower cobalt content.

Figure 4. Edge durability depending on hardness Figure 5. Edge durability depending on cobalt content

Sinters of grain size of 0.2–0.5µm (Ultrafine Grade) has higher hardness and bending strength compared to carbides of grain size of 0.5–0.8 µm (Fine Grade) and 0.8–1.3 µm (Submicron Grade), which results in a higher wear resistance of tools (Figure 4). The smaller the WC grain size, the higher the number of borders between grains, giving higher hardness of edges. Furthermore, the edge hardness increases along with the decrease of the content of soft adhesive binder – cobalt. Figure 5 shows the graph of relation between edge hardness depending on cobalt content. A sample image of cutting edge is shown on Figure 6. The edges of the smallest WC grain size showed higher resistance to the chipping of the cutting edge.

Figure 6. Chipping of WCCo tool material (SEM image)

Figure 7 shows the microstructure of blade fractures. The analysis of the image of the micro-structure of Ultrafine blade fracture shows homogeneous, low-grain microstructure, with cobalt evenly spread over WC grains. The image of the micro-structure fractures also reveals a few pores. However, the tests showed that small internal structure porosity did not affect the durability of edges made of this material. These blades were of the highest hardness and were worn slowly. The SEM image of Submicron blade fracture shows that the micro-structure is heterogeneous. There are larger and smaller WC grains, also pores appear. Furthermore, the micro-structure also reveals well-formed WC grains with specific sharp edges. Figure 7c shows the blades characterized by the largest average WC grain size. The images of the microstructure also show heterogeneousness resulting from the presence of differently- sized WC grains. Furthermore, well-formed WC grains can be observed. Pores are not observed.

a) Ultrafine grain (0. 2<0.5 μm)

b) Submicron grain (0.5<0.8 μm)

c) Fine grain (0.8<1.3 μm)

Figure 7. SEM images of the fracture surfaces of WCCo blades

CONCLUSIONS This study shows that cutting edges made of WCCo composite of WC grain size 0.2– 0.5 μm were increasingly more durable compared to edges of larger WC grains. The lower the content of the binder (cobalt), the higher the material hardness and, as a result, the higher the durability of the blades in particleboard machining. A homogeneous microstructure of 0.2–0.5 μm blades determines high durability and even wear of the blade through abrasion. A heterogeneous microstructure in the form of differently-sized WC grains results in a decrease of tool durability as well as in chipping of the edge of the blade.

REFERENCES

1. DYBA W. (2017): Furniture Clusters in the Spatial Structure of the Furniture Industry in Studies of the Industrial Geography Commission of the Polish Geographical Society 31.1, pp. 38–51 2. NIZIAŁEK I., PODOBAS I., and KNYSAK A., (2016): Ekoinnowacje na przykładzie przedsiębiorstw z branży meblarskiej. Przedsiębiorczość i Zarządzanie 17.6, cz. 2 Firmy rodzinne-wyzwania współczesności, pp. 241–253 3. SZWAJKA K., and TRZEPIECIŃSKI T., (2017): The influence of machining parameters and tool wear on the delamination process during milling of melamine- faced particleboard. Drewno: prace naukowe, doniesienia, komunikaty 60 4. KOWALUK G., SZYMAŃSKI W., BEER P. (2007): Influence of tools stage on particleboards milling. Wood Research 52 [3], pp. 75–88 5. WILKOWSKI J. et al. (2017): Effect of laser modification of WC-Co tool-life during particleboards milling. Forestry and Wood Technology No 98 Warsaw, p. 148 6. SIWAK P., GARBIEC D., and CHWALCZUK T. (2015): Badania właściwości technologicznych płytek skrawających z węglików spiekanych typu WC-6Co wytwarzanych metodą impulsowo-plazmową. Mechanik 88.8-9CD2, pp. 113–122 7. ROSIŃSKI M., et al. (2012): Właściwości kompozytu WCCo spiekanego metodą PPS. Materiały Ceramiczne/Ceramic Materials 64.3 (2012) , pp. 319–323 8. KUPCZYK M. J., (2009): Wytwarzanie i eksploatacja narzędzi skrawających z powłokami przeciwzużyciowymi, Wyd. Politechniki Poznańskiej 9. BOBZIN K. (2017): High-performance coatings for cutting tools. CIRP Journal of Manufacturing Science and Technology 18, pp. 1–9 10. MENG R., et al. (2018): Improving tribological performance of cemented carbides by combining laser surface texturing and WSC solid lubricant coating. International Journal of Refractory Metals and Hard Materials 72, pp. 163–171 11. FANG Z. et al. (2009): Synthesis, sintering, and mechanical properties of nanocrystalline cemented tungsten carbide–a review. International Journal of Refractory Metals and Hard Materials 27.2,pp. 288–299 12. FABIJANIĆ T.A. et al. (2016): Influence of consolidation process and sintering temperature on microstructure and mechanical properties of near nano-and nano- structured WC-Co cemented carbides. International journal of refractory metals and hard materials 54, pp. 82–89

Streszczenie: Wpływ wielkości ziarna WC na trwałość ostrzy skrawających wykonanych z kompozytu WCCo w obróbce materiałów drewnopochodnych. Węgliki spiekane WCCo są jednym z podstawowych materiałów narzędziowych. Składają się one w 70–96% z węglika wolframu oraz z osnowy wiążącej - kobaltu. Wysoka twardość tych materiałów decyduje o ich wysokiej odporności na zużycie ścierne. W pracy przedstawiono wyniki badań trwałości ostrzy skrawających wykonanych z kompozytu WCCo o rożnej wielkości ziarna WC, w obróbce materiałów drewnopochodnych. Badania trwałości, wykazały kilkukrotny wzrost trwałości ostrzy wykonanych z kompozytu WCCo, o wielkości ziarna 0,2÷0,5 µm w porównaniu do ostrzy WCCo o wielkościach ziarna WC 0,5÷0,8 μm oraz 0,8÷1,3 μm.

Corresponding author:

Joanna Wachowicz, Warsaw University of Life Science – SGGW Faculty of Wood Technology 159 Nowoursynowska St. 02-787 Warsaw, Poland email: [email protected]

ORCID ID: Wilkowski Jacek 0000-0001-5798-6761 Wachowicz Joanna 0000-0002-7942-3959 Czarniak Paweł 0000-0001-8759-7679

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 72-79 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Influence of qualitative and dimensional classification of Pinewood raw material as an efficiency indicator in the production of selected timber assortments

MAREK WIERUSZEWSKI, RADOSŁAW MIRSKI, ADRIAN TROCIŃSKI, JAKUB KAWALERCZYK Department of Wood Based Materials, Faculty of Wood Technology, Poznan University of Life Sciences

Abstract: Wood processing plants in Poland are recipients of more than 50% of round wood, which is delivered by the State Forests National Forest Holding. Thus playing a crucial role in the technological processing of raw material for all other wood industry branches. Each group of recipients has individual needs and expectations concerning the quality of the raw material such as, its type and the size of the cross-sections of the assortment used for further production. Therefore, it is economically justified for small production plants to abandon the production of narrow groups of assortments, which usually meets the standards of timber for general purposes. The aim is to make wood processing more flexible and lower the quality of raw material to produce assortments for a specific branches of the wood industry. Wood processing experiments were conducted to produce laths for construction purposes. These materials are one of the most important elements of roof constructions. The research proved empirically that it was possible to produce quality class 1 laths (88% of all laths produced) from WC0 class pinewood used as the input raw material and that the quantitative efficiency exceeded 55%.

Keywords: round wood, pinewood, material efficiency INTRODUCTION Scots pine (Pinus sylvestris L.) is a species of the pine family (Pinaceae) [Forest Encyclopaedia]. It is a prevalent species in Polish forests (58.2% of the forest area in Poland). More than 6.5 million m3 of this raw material is acquired per annum. In 2017 the State Forests National Forest Holding acquired a total of 40.2 million m3 of wood, 60% of which was pinewood [State Forests, 2017]. Due to the high availability of raw wood in Poland, a relatively low price and very good technical properties pinewood is a species used in many branches of the wood industry, especially in the sawmill industry, the board industry, and the cellulose and paper industry. Depending on the size and quality of raw material, wood processing plants use their stock of medium- and large-sized wood for the production of:  construction timber – the material is used for the construction of houses and bridges. It is acquired as a result of visual or mechanical sorting of solid softwood [Kotwica et al., 2015]. It is tested for strength according to the Polish Standard PN-EN 14081-1: 2007. Once wood meets the requirements concerning mechanical properties and density, timber is assigned to the appropriate strength class C, according to the Polish Standard PN-EN 384: 2016, and it receives the CE mark. Construction material meets the highest strength requirements due to its qualitative characteristics [Kozakiewicz & Krzosek, 2013].  fenestration joinery – there are high requirements concerning timber used for manufacturing these products. It can be divided into indoor fenestration joinery (requirements specified in the Polish Standard PN-EN 14221: 2007) and outdoor fenestration joinery (requirements specified in the Polish Standard PN-EN 14220: 2007). In order to be processed further wood must be characterised by high strength and it must be free of most defects, which need to be eliminated, e.g. by bonding with adhesives. Apart from that, wood must be characterised by good workability in

finishing processing and by dimensional stability. The light colour of the sapwood zone allows easy coating of the structure with colourless or pigmented varnish [Dubiela,2011].  solid and layered flooring – pinewood is characterised by medium abrasion resistance, but it is relatively low-priced, has attractive appearance and it is easy to process. The requirements concerning the quality of timber are specified in the Polish Standard PN- EN 13999:2004. Pinewood (low-value assortments) is also used as a base in multilayer floorings, on which a decorative layer (e.g. hardwood/valuable wood) is placed.  general purpose timber – it is made from medium quality raw material in wood processing plants. The dimensions of cross-sections and lengths and the quality classes of timber are diversified. The quality class of the assortment is determined by the share of defects. The high dimensional and qualitative diversity of pine timber results in a wide range of assortments meeting customers’ expectations. The timber is classified according to the Polish Standard PN-75/D-96000 or PN-EN 1611-1: 2002.  products of the garden programme – they represent the branch of the wood industry, which makes use of large-size raw materials of lower quality, in the form of medium- size timber (S2B). These products are mostly used for protection and decoration. These are mainly: shelters, privacy fences, pergolas, border edgings, log roll and many more.  packaging products – these are mainly EUR-pallets and packaging boxes for the storage and transport of machinery and loose materials. Depending on the type of pallets produced, the standard defines permissible defects in pine timber from which the constructions of pallets are made. Due to the wide structure of products made from pinewood, not only the qualitative and dimensional classification, but also the intended use plays a decisive role. One of the major priorities of the State Forests, which is the main supplier of raw wood in Poland, is to adjust the dimensions and quality characteristics of pinewood offered on the domestic market. MATERIAL AND METHODS The research was conducted in a wood processing plant situated in the south of Wielkopolska Voivodeship. About of pinewood (Pinus sylvestris L.) in the form of 12-metre- long logs was analysed.

where: SPK 1/250 – flitch height: 250 mm; p = 2.3 – saw kerf: 2.3 mm Figure 1. A scheme of sawing a log into flitches Material was handled in a technological line using an electronic log shape measurement system, which enabled the optimisation of efficiency and the selection of a technologically adequate division into logs. After the handling process, wood was sorted into groups according to its diameter at the thinner end, where the gradation was - each 2 cm. At a

73 later stage the diameter ranges determine the height of resulting flitches. The next stage concerns sawing, i.e. the process in which raw material in the form of round wood is processed into prisms (Fig. 1). A Primultini SGF 1300 machine tool (vertical frame saw) was used for this purpose. Flitches were processed with a Raimann KRD 430 twin-shaft multi-blade saw, where they were divided into balks. The thickness of balks was constant, i.e. 58 mm (Figure 2). The end product, i.e. construction laths, was made from this dimension. The kerf thickness (4.4 mm) was also included in the cutting process. It depended on the thickness of the circular saw blades used for cutting. The amount of balks obtained by sawing depended on the diameter of assortment. Usually four or five sharp-edged main assortments were produced from one flitch.

Figure 2. A scheme of sawing flitches into balks Final stage of the technological process results in balks sawn into laths, which were the end product of this research. A multi-blade longitudinal saw was used for this operation (only the lower shaft), according to the sawing setting shown in Figure 3. Six laths were made from each flitch.

Figure 3. A scheme of sawing flitches into laths

At individual stages of the technological process side products in the form of offcuts were separated (depending on the log diameter) and they were sent for further processing. The resulting product was general purpose timber – 20- or 25-mm-thick planks, which were later offered for sale. Each stage of the technological process included the assortments visual quality assessment, in accordance with the applicable standard, depending on the type (assortment) of the material tested. Qualified sorters determined the quality class by assessing the assortments visually according to the Polish Standard PN-75-D-9600. The balks that did not meet the quality requirements for a specific type of sawn materials were sent to be processed into planks together with side materials. The timber thickness and other measurements were made according to the Polish Standard PN-D-95000: 2002. RESULTS AND DISCUSSION The long logs used in the research underwent qualitative analysis (Fig. 4). The share of the logs in individual quality classes was as follows: WA0 – 0%, WB0 – 1.7%, WC0 – 64.6%, WD0 – 33.6%. Wood processing plants usually purchase long pine logs of the WC0 quality class due to the best ratio between the round wood price and the qualitative and quantitative

74 indicators of the sawing efficiency. The long pine logs were additionally divided into classes of thickness in the middle of their length in order to make a more accurate analysis (class 1 – up to 24 cm in diameter, class 2 – 25-34 cm in diameter, class 3 – above 35 cm in diameter). Thickness class 2 was the most common of all quality classes. Results and observations led to the conclusion that the long pine logs of the WC0 class were the most suitable material for further investigations. 37 logs (20.71 m3) were sorted out and sent for further processing.

Figure 4. The percentage of pine logs in individual quality and thickness classes The handling resulted in 56 logs with volume amounting to 21.4 m3. The share of the logs in individual quality classes was as follows: WA0 – 0%, WB0 – 27%, WC0 – 53%, WD0 – 20%. The logs in the abovementioned quality grades were further divided according to their diameters (Fig. 5).

Figure 5. The dependence between the log quality class and its diameter (without bark) The WC0 class was predominant in each diameter range. The logs that did not exceed 40 cm in diameter had the largest share in the WB0 class. Like the WB0 class, the WD class was represented by the logs whose diameters did not exceed 40 cm. There were no logs in the WA0 class. Unfortunately, the data were not sufficient enough to find a clear correlation between the log quality class and its diameter. Figure 6 shows the results of the log qualitative efficiency, which was calculated as the ratio between the weight and volume of the long logs in individual quality classes. The low quality of the input raw material resulted in the

75 predominance of the WC0 quality class and the lack of the WA0 class. The long logs which were included in the WD class were qualified to it mainly due to curvatures, which made it impossible to obtain large weights of log wood in higher quality classes. However, the division into logs reduced the share of the lowest quality class, i.e. WD, by nearly 14%. It is noteworthy that the share of the WC0 class dropped by nearly 10%, whereas the share of the raw material in the WB0 class increased over 15 times.

Figure 6. The material and quality efficiency of the logs These facts confirm the material efficiency standard in the wood processing plant. After the manipulation the total material efficiency of the logs was 103%. The xylometric paradox, which is determined by tapering and corrected by sequential measurement of the raw material, confirms the increase in the efficiency of logs, as compared with the long logs (Korczewski et al. 1970).

Figure 7. The material and quality efficiency of the balks Within the next stage of the research the quantitative and qualitative material efficiency of the balks was determined. After the logs were cut into flitches and balks, 224 pieces of main timber were obtained in total, with a total volume of 12.99 m3. The calculations did not include offcuts and side planks produced during processing, because they were sent for further processing and production of other elements. Figure 7 shows the material efficiency, which was determined in two stages of the technological process: in the form of flitches and sawn products. 18 balks were qualified for quality class 1, which resulted in

76 material efficiency of about 5%. It is noteworthy that only at this stage of processing the raw material of the highest quality was obtained. Assortments of quality classes 2 and 3 were the largest group of the resulting raw material. Their material efficiency in relation to the long logs amounted to 25% and 23%, respectively. The balks of the lowest quality class (class 4) made nearly 9% of the volume of the semi-finished products obtained in processing. Despite the low quality of the input raw material, i.e. long logs, the handling and sawing resulted in good quality balks, because defects in the structure of round wood were significantly reduced by sawing and further prefabrication. Table 1. The material efficiency of construction laths Quality class Volume in quality class Material efficiency in quality class in relation to long logs Wjpkl/d 1 10.21 49.2 2 1.33 6.4 Total 11.54 55.6

During the last stage of the research, results of the technological process of dividing balks into construction laths were verified. In total there were 1,309 laths produced, which amounted to 11.54 m3 of wood. The volume difference between the balks (12.99 m3) and the quantitative efficiency of laths amounted to about 11%. There were losses generated only by the material removed during sawing, which directly depended on the saw blade thickness (4.4 mm). Table 1 shows the material and quality efficiency in relation to the input assortment, i.e. the long logs. The assortment of quality class 1 was the dominant group of end products (about 88% of all laths made). Despite the low quality of the input raw material, the material efficiency of the end products in quality class 1 amounted to nearly 50%. The research results suggest that it is not economically justified to produce construction laths from round wood of higher quality classes, as it is more expensive. The material efficiency of the construction laths amounted to almost 56%. This value was within the manufacturing standard for sawn products and shows that the technological process was executed well. CONCLUSIONS 1. The analysis conducted on the selected production plant showed that WC0 was the largest quality class of available pinewood. Raw pinewood material is categorised as the WD quality class mainly due to excessive shape defects in long logs. 2. The analysis of the research results showed that the greatest decrease in efficiency occurred during the process of sawing the flitches into the balks. It was caused by the large amount of sawmill by-products generated at this stage, which did not occur at the consecutive stages of processing. 3. Proper adjustment of processing, which allows for the available base of raw materials, guarantees high quality assortments. The share of laths belonging to quality class 1 in the total volume of laths was as high as 88%. 4. The analysis of the efficiency indicators leads to the conclusion that pinewood in the WCO quality class fully meets the quality requirements for the production of construction laths. The principles of qualitative and dimensional classification, which allow for the occurrence of knots, but do not allow rotten wood, considerable discoloration or insect paths, have decisive influence.

The presented research were co-financed by The National Centre for Research and Development under Strategic research and development program „Environment, agriculture and forestry" – BIOSTRATEG agreement No. BIOSTRATEG3/344303/14/NCBR/2018.

REFERENCES

1. BUCHHOLZ, J., 1990: Technologie tartacznictwa. Wydawnictwo Akademii Rolniczej w Poznaniu. Poznań 1990. 2. DUBIELA, S., 2011: Jakie gatunki drewna wykorzystuje się w stolarce okiennej. Pozyskano z: https://ekobudowanie.pl/zdaniem-eksperta/1481-jakie-gatunki- drewna-wykorzystuje-sie-w-stolarce-okiennej 3. ENCYKLOPEDIA LEŚNA: Hasło Sosna zwyczajna. Pozyskano z: https://www.encyklopedialesna.pl/haslo/sosna/ 4. KOTWICA E., NOŻYŃSKI W., 2015: Konstrukcje drewniane – przykłady obliczeń. Stowarzyszenie producentów płyt drewnopochodnych w Polsce. s.13-16. 5. KOZAKIEWICZ, P., KORZOSEK, S., 2013: Inżynieria materiałów drzewnych. Wydawnictwo SGGW. 82-86. 6. LASY PAŃSTWOWE, 2017: Lasy w Polsce 2017. Pozyskano z: http://www.lasy.gov.pl/pl/informacje/publikacje/do-poczytania/lasy-w-polsce- 1/lasy-w-polsce-2017-pl-internet.pdf 7. PN-75/D-96000: 1975, Tarcica iglasta ogólnego przeznaczenia. 8. PN-D-95000:2002, Surowiec drzewny - Pomiar, obliczanie miąższości i cechowanie 9. PN-EN 384: 2016, Drewno konstrukcyjne -- Oznaczanie wartości charakterystycznych właściwości mechanicznych i gęstości. 10. PN-EN 1611-1: 2010, Tarcica -- Klasyfikacja drewna iglastego na podstawie wyglądu – Część 1: Europejskie świerki, jodły, sosny i daglezje. 11. PN-EN 13999:2004, Podłogi drewniane Deski podłogowe z drewna iglastego litego. PN-EN 14081 – 1:2007. Konstrukcje drewniane -- Drewno konstrukcyjne o przekroju prostokątnym sortowane wytrzymałościowo -Część 1: Wymagania ogólne. 12. PN-EN 14220:2007, Drewno i materiały drewnopochodne w zewnętrznych oknach, zewnętrznych skrzydłach drzwiowych i zewnętrznych ościeżnicach. Wymagania jakościowe i techniczne. 13. PN-EN 14221:2007, Drewno i materiały drewnopochodne w wewnętrznych oknach, wewnętrznych skrzydłach drzwiowych i wewnętrznych ościeżnicach. Wymagania jakościowe i techniczne.

Streszczenie: Wpływ doboru jakościowo wymiarowego surowca sosnowego, jako wskaźnik wydajnościowy w produkcji wybranych sortymentów tarcicy. Zakłady pierwiastkowego przerobu drewna w Polsce są odbiorcami ponad 50% drewna w postaci okrągłej, sprzedawanego przez Państwowe Gospodarstwo Leśne „Lasy Państwowe”. Tym samym odgrywają decydującą rolę na drodze technologicznego przetworzenia surowca dla pozostałych gałęzi przemysłu drzewnego. Każda z grup odbiorców posiada indywidualne potrzeby dotyczące jakości wykorzystywanego surowca, gatunku oraz wielkości przekrojów poprzecznych sortymentu wykorzystywanych do własnej dalszej produkcji. Stąd ekonomicznie uzasadnione jest, odchodzenie mały zakładów produkcyjnych od wytwarzania wąskich grup sortymentów, często zgodnych z normami tarcicy tartacznej ogólnego przeznaczenia. Dąży się do uelastycznienia przerobów i wytwarzanie sortymentów pod konkretną gałąź przemysłu z surowca niższej jakości. Dla celów badawczych przeprowadzone

78 zostały przeroby doświadczalne uwzględniające pozyskanie łat budowlanych. Są to materiały, będące jednym z ważniejszych elementów konstrukcji dachowych. Doświadczalnie oraz empirycznie udowodnione zostało, że w odniesieniu do surowca wejściowego, jakim jest drewno sosnowe klasy WC0, możliwe jest wytwarzanie łat zaklasyfikowanych do I klasy jakości (stanowiącej 88% z wszystkich wytworzonych łat) z wydajnością ilościową przekraczającą 55%.

Słowa kluczowe: drewno okrągłe, sosna, wydajność materiałowa

Corresponding author:

Wieruszewski, Marek Department of Wood-based Materials, Faculty of Wood Technology, Poznan University of Life Sciences, Poznan, Poland [email protected]

ORCID ID: Wieruszewski Marek 0000-0002-4867-195X Mirski Radosław 0000-0002-4881-579X Kawalerczyk Jakub 0000-0002-5539-1841

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 80-83 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Timber cross-cutting accuracy obtained with an automatic saw

SZYMON NIECIĄG1, TOMASZ ROGOZIŃSKI2 JACEK WILKOWSKI3, BARTOSZ PAŁUBICKI4,5 1 P.P.U.H. STOLMAK Krzysztof Nieciąg, Żarnówka 118, 34-220 Maków Podhalański 2 Poznań University of Life Sciences, Faculty of Wood Technology, Department of Furniture Design 3 Warsaw University of Life Sciences, Department of Mechanical Processing of Wood 4 Poznań University of Life Sciences, Faculty of Wood Technology, Department of Woodworking Machines and Fundamentals of Machine Design 5 UPTO, Poznań, os. Wichrowe Wzgórze 36/10

Abstract: Timber cross-cutting accuracy obtained with an automatic saw. The aim of this study was to verify the accuracy of cross-cutting of Scots Pine timber with use of optimization cross-cut saw Salvador Supercut 500. An influence of nominal element length and thru-feed speed was examined and analyzed with statistical methods.

Keywords: sawing, cross-cutting accuracy, wood machining

INTRODUCTION Timber cross-cutting is a very frequently performed technological operation in wood industry. Mostly high-performance cross-cut optimizers entirely replace manual work on circular saws, decreasing labor costs and augmenting production yield. Numerous literature available concerns rip-sawing accuracy in sawmills (Eklund 2000, St. Laurent 1970), since, in most cases, it influences more the material yield, than cross-cutting. Cross-cutting optimization issue was described by Ronnqvist M. and Astrand E. (1998) for fixed-length products as well as for continuous-length products. For the second solution, defects of wooden boards are cut out on the basis of automatic scanning and image analysis or by worker visual assessment and cutting lines marking. This is mainly a part of a longitudinal wood joining lines, which do not require specific lengths of elements. On the other hand automatic optimizing cross-cut saws may also be utilized as a stand-alone machines for production of elements of strictly defined length with or without taking into consideration the defects and quality classes. In such case a compliance between demanded and real dimension (length) arises to a crucial issue. For simple cross-cutting mode the roughness of created surfaces were examined by Kminiak and Gaff (2015) and depending on: wood species, saw blade type and feed force. The length accuracy relies mostly on infeed (board positioning) system, which requires dynamic accelerations and decelerations. The aim of present work was to examine the length accuracy of pine boards after timber cross-cutting on automatic optimizing saw Salvador Supercut 500, depending on boards’ nominal length and thru-feed speed.

MATERIALS AND METHODS The boards of Scots Pine with moisture contents of 10-14% have been planed with use of four-side moulder before the experimental work. The boards after planing with dimensions: 15 mm thick, 65 mm wide and 2600 mm long were subjected to cross-cutting with three cutting lengths ordered: 384 mm, 850 mm and 1500 mm. In current experiment wood defects cut-out was not involved; the mode used was simple cutting list order. In this mode the cycle on Salvador Supercut 500 saw included: length scanning, in-feed timber movement, stopping

80 the board to cut-off its termination, accelerating to a maximal travel speed allowed (if element is long enough to achieve it) and length cutting. In such cycle it is impossible to set up the travel speed of the board since it is variable and changes from zero to maximal and back to zero. Therefore the producer allows regulations of percentage of maximal material traveling speed (150 m/min – Anonymus (2013)) as well as acceleration and deceleration. For purposes of present work 40%, 70% and 100% speeds were chosen. For each of 9 cases considered: three nominal length by three speed levels, 50 specimens were produced and measured, giving total 450 boards. The measurements were performed with use of the caliper with 1540 mm measurement range and 0,05 mm of precision. Next a discrepancy of stock length was calculated as a difference between the measured and nominal lengths. Additionally an error (e) of cut length was evaluated according to the following formula: % where: LR – length measured LN – nominal length

RESULTS

a) b)

Figure 1. Histograms of cut length discrepancy for nominal lengths: a) 384 mm, b) 850 mm, c) 1500 mm

Histograms of cut length discrepancy are shown in the figure 1. The scatter of length dimension discrepancy covers values from -2 mm up to 4 mm. Relatively to the nominal length the errors of cut length start at –0.469% and reach +0.664%. It is evident, since discrepancies are mainly positive, that the saw oversizes the boards for all nominal lengths and speed levels. Population peaks for 384 mm and 850 mm, located around 1 mm, visibly

81 shift with increasing nominal length toward 1500 mm and reach values 2 and 3 mm, Saw work speed (% of full); Oczekiwane średnie brzegowe depending on thru-feed speed. A tendencyLambda Wilksa=,94383, for theF(4, 880)=6,4521, thru-feed p=,00004 speed level is not clearly visible. Dekompozycja efektywnych hipotez Pionowe słupki oznaczają 0,95 przedziały ufności 0,22 0,20 0,18 0,16 0,14 0,12 0,10 0,08

Cut length error (%) error length Cut 0,06 0,04 0,02 40 70 100 Saw work speed (% of full) Figure 2. One-way analysisNominal of cut variancelength (mm); Oczekiwane for saw średnie work brzegowe speed and cut length error. VerticalLambda lines Wilksa=,25573, denote 0,95 F(4, 880)=215,05, level of p=0,0000 confidence Dekompozycja efektywnych hipotez Pionowe słupki oznaczają 0,95 przedziały ufności 0,22 0,20 0,18 0,16 0,14 0,12 0,10 0,08 0,06

Cut length error (%) 0,04 0,02 0,00 384 850 1500 Nominal cut length (mm) Figure 3. One-waySaw workanalysis speed (% of full)*Nominal variance cut lengthof nominal (mm); Oczekiwane cut średnielength brzegowe on cut length error. Lambda Wilksa=,88929, F(8, 880)=6,6462, p=,00000 Vertical linesDekompozycja denote 0,95efektywnych level hipotez of confidence Pionowe słupki oznaczają +/- błąd standardowy 0,35 Nominal cut length (mm) 384 0,30 Nominal cut length (mm) 850 Nominal cut length (mm) 1500 0,25

0,20

0,15

0,10

Cut length error (%) 0,05

0,00

-0,05 40 70 100 Saw work speed (% of full) Figure 4. Two-way analysis of variance of nominal cut length on cut length error

To verify and validate tendencies, a one- and two-way analysis of variance (ANOVA) has been utilized with use of Statistica software. Firstly one–way ANOVA was performed for saw work speed and cut length error (e). Figure 2 presents that increasing the work speed leads to reduction of cut length error. In considered length range this relation (reduction from 0,16% to 0,07%) monotonic, however discrimination power of work speed (independent variable) is rather poor since Wilks’ Lambda = 0,9438.

Second independent variable – nominal cut length, in opposition, has a strong contribution to the variance model (Wilks’ Lambda = 0,2557). Its relation to the cut length error is not monotonic though (fig. 3). The average error of cut length is the smallest for medium timber length (850 mm) and equals 0,052% and increases both for shorter and longer boards. Two-way ANOVA model presented in figure 4 does not bring any better determination that above discussed. The mixed variable model has Wilks’ Lambda value on the not satisfying level of 0,889.

CONCLUSIONS Experiment preformed on cross-cutting accuracy of automatic optimizing cross-cut saw allows to form the following conclusions:  The discrepancy of cut length was from -2 mm up to 4 mm  The saw work speed rather does not influence the sawing accuracy.  The cut length error strongly depends on the nominal cut length, but this dependency is not monotonic

REFERENCES

1. Anonymus 2013: Salvador Supercut 500 Manuals, version 10.02. Salvador woodworking machinery 2. Eklund U. 2000: Influencing factors on sawing accuracy in a bandsawmill, Holz als Roh- und Werkstoff 58: 102-106 3. Kminiak R., Gaff M. 2015: Roughness of surface created by transversal sawing of spruce, beech, and oak wood. BioResources, 10(2): 2873-2887 4. Ronnqvist M., Astrand E. 1998: Integrated defect detection and optimization for cross cutting of wooden boards, European Journal of Operational Research 108 (3): 490-508 5. St. Laurent A. 1970: Effect of sawtooth edge defects on cutting forces and sawing accuracy, Forest Products Journal 20 (5): 33-40

Streszczenie: Dokładność cięcia poprzecznego drewna na pilarce automatycznej. Celem niniejszej pracy była weryfikacja dokładności cięcia poprzecznego drewna sosny zwyczajnej za pomocą optymalizerki Salvador Supercut 500. Zbadano wpływ nominalnej długości elementów i prędkości przesuwu oraz przeanalizowano uzyskane wyniki metodami statystycznymi.

Corresponding author:

Bartosz Pałubicki, ul. Wojska Polskiego 38/42, 61-637 Poznań, Poland, email: [email protected] phone: +48 61 848 7490

ORCID ID: Bartosz Pałubicki 0000-0003-3915-1781 Jacek Wilkowski 0000-0001-5798-6761

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 84-103 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Traditional ornaments of Świdermajers’ style windows in the town of Otwock

MARTA DWORNIK, ANNA ROZANSKA1, PIOTR BEER1 1 Department of Technology and Entrepreneurship in Wood Industry, Institute of Wood Sciences and Furniture, Warsaw University of Life Sciences WULS-SGGW, Poland

Abstract: The paper provides an analysis of windows in antique Świdermajers’ style wooden buildings, located in Otwock. It has been discovered that many of them have been already replaced with new ones. Attention was paid to the traditional Polish casement window structure with transom and the main part below, additionally divided into smaller areas by wooden horizontal or vertical muntins. Analysis of traditional window carpentry elements such as shutters, window sills, cornices and batten frames was made together with their classification based on different kinds of decorative motifs.

Keywords: wooden architecture, window, Świdermajer, Otwock, ornaments

INTRODUCTION Świdermajer is a style popular along the Świder River. The term was first used as a joke in a poem by Konstanty Ildefons Gałczyński. It refers to the wooden architecture of summer cottages that started to appear in late 19th century along the railway line built along the Vistula River, South-East from Warsaw [Lewandowski, 2012]. Currently, most of the buildings that have been preserved - some quite well, others poorly - are in the town of Otwock. In spite of the fact that modern buildings made of brick tend to respect the details and ornaments characteristic for that style, the number of original buildings keeps falling. The Świdermajer buildings do not follow just one single architectural cannon. The author of this style, Andriolli, drew inspiration from both Russian style and alpine architecture, as well as the medieval tradition of timber frame construction. The buildings had different functions: from private houses to hotels or health resorts. All differed in dimensions, level of splendour and interior equipment. The layout was rectangular, with the so called "light construction" of the walls, usually timber frame, used in smaller buildings. For larger buildings composed of several storeys, other types of construction were also applied: log walls, and post and beam structure. However, the common feature of this type of architecture consists in the unique verandas typical for health resorts, as well as rich fretwork, woodcarving decorations. They appear as openwork filling of roofs, supports, friezes, ballustrades, ornamental bands below and above the windows; and they make use of floral, zoomorphic, and geometrical motifs, combined with decorative monograms or stucco medallions hanging on building façades [Radomska, 2001]. Buildings are covered with decorative boarding (boards covering the external walls) and have little towers finished with ornamental pinnacles and covered with tent-like roofs [Radomska, 2001]. The main material used to build a Świdermajers’ houses was wood. It was used not only for the construction itself such as roof trusses, structural bars and posts, but also for external wall boarding or ornaments of roofs, windows and verandas. In the second half of the 19th century, sawn timber was becoming more and more popular in construction, together with fretwork ornaments. The name comes from the fretsaw: a type of saw used to make intricate cutting work in wood.

Table 1. Buildings included in the research Year of Year of No. Address construction No. Address construction 1 Andriollego 35 ca. 1890 41 Mickiewicza 25 1905 2 Andriollego 66 ca. 1930 42 Mickiewicza 31 1st quarter 20th c. 3 Bagatela 27 before 1939 43 Mickiewicza 33 1st quarter of 20th c. 4 Chopina 16 1890s 44 Mickiewicza 35 1st quarter of 20th c. 5 Chopina 17 early 20th c. 45 Mickiewicza 43/47 1930s 6 Czarnieckiego 6 before 1939 46 Mickiewicza 44/50a before 1939 7 Dębowa 3 before 1939 47 Mickiewicza 44/50b before 1939 8 Emilii Plater 41 before 1939 48 Moniuszki 13 before 1939 9 Fredry 9 1908 49 Moniuszki 19 1920 10 Fredry 18 no data 50 Moniuszki 20 1925 11 Glinicka 11 1930s 51 Moniuszki 23 1929 12 Górna 104 ca. 1900 52 Moniuszki 27 1920s 13 Jana Pawła 13 1920s 53 Moniuszki 25 1920s 14 Jaremy 5 ca. 1935 54 Moniuszki 29 before 1939 15 Jaremy 7 ca. 1935 55 Narutowicza 51 before 1939 16 Kołłątaja 29 1928 56 Narutowicza 53 1924 17 Konopnicka 4 before 1939 57 Piaskowa no data 18 Konopnickiej 7 ca. 1910 58 Piłsudskiego 22 1933 19 Konopnickiej 7a 1926-27 59 Poetycka 5 before 1939 20 Kościelna 18 1910/1935 60 Poetycka 21 1910 21 Kościelna 22 1st quarter of 20th c. 61 Pogodna 6 early 20th c. 22 Kościelna 23 1st quarter of 20th c. 62 Pogodna 7 before 1939 23 Kościuszki 5 1924 63 Poniatowskiego 11 before 1935 24 Kościuszki 7 ca. 1925 64 Prusa 13 1912 25 Kościuszki 15 1899 65 Reymonta 29 1906 26 Kościuszki 19 1890 66 Samorządowa 8 1927 27 Kościuszki 21a ca. 1905 67 Samorządowa 22a 1929 28 Kościuszki 29 1st quarter of 20th c. 68 Samorządowa 16/20 1920 29 Kościuszki 32 1937 69 Słoneczna 8 before 1939 30 Kościuszki 39 1st quarter of 20th c. 70 Słoneczna 15 before 1939 31 Kraszewskiego 101 1920 71 Sowińskiego 6a before 1939 32 Krótka 10 before 1939 72 Sucha 7 before 1939 33 Lelewela 7 before 1939 73 Świerkowa 16 ca. 1925 34 Literacka 6 1930s 74 Turystyczna 18 before 1939 35 Majowa 8 1930 75 Wiązowska 29 1920 36 Majowa 24 1920s 76 Wierchowa 15 before 1939 37 Mała 5 1920s 77 Willowa 6 before 1939 38 Mała 3 1930s 78 Zaciszna 26 1920 39 Marusarzówny 27 1st quarter of 20th c. 79 Żeromskiego 10 ca. 1900 40 Mickiewicza 23 1905 80 Żeromskiego 60/62a 1930

Such wood-carvings were the main decorative element in Świdermajer buildings, and the handbook of decoration patterns published in 1880 by a German architect, Bernard

Liebold, became the basic reference for craftsmen from the Świder area. The handbook included very detailed drawings of wood-carving, as well as façades, verandas, ornaments, profiled beams and many other elements [Lewandowski, 2012]. Thanks to Bernard Liebold, the characteristic wooden architecture of European health resorts was formed at the turn of the 20th century [Ruszczyk, 2007]. A huge demand for wooden buildings in Otwock was a cause for sawmills and carpenters higher demand. One of them was Marcin Sierpiński, a carpenter specialising in doors, windows with shutters, and window sills. He took part, just like later his grandson Mieczysław Sierpiński, in the construction of many summer cottages in Świder and Józefów [localities near Otwock, along the Świder River]. Another carpenter, Leon Turski, moved to Otwock in 1895, started his professional career there and in 1905 built a house in Michalin with details inspired by Liebold's pattern handbook [Lewandowski, 2012]. Otwock was the workplace of eminent architects, such as Władysław Marconi, son of the famous Warsaw architect, Henryk Marconi, as well as Władysław Noakowski, Wacław Kupsta or Zdzisław Przygoda [Radomska, 2001]. Apart from the fretsaw and patterns by Liebold, carpenters and woodworkers also used traditional tools such as mallet and chisel. Cuts of these are visible in the engraved window sills and cornices. Hatchets (to debark logs and then give them a rectangular shape), axes (for wedge cuts and carpentry joints, as well as sharpening post ends), two man crosscut saws and saws for longitudinal cuts were also popular tools. In the interwar period, the forms of Świdermajer buildings changed, as larger, several- storey buildings were being erected. Their decorations tended to be less elaborate, less precise and done carelessly. The decorative motifs became more geometric, the ornaments were based on similar patterns, with dubious quality and no sophisticated details, which left much to be desired. What remained unchanged were the verandas, always present in Świdermajer buildings, independently of the construction time [Radomska, 2001], as well as the characteristic decorative wall panels made of boarding with ornamental friezes between storeys [Cichy, 2007].

A B Figure 1. Ruined building at Kościuszki 29 Street: A- veranda, current state, B- collapsed ceiling inside.

RESEARCH AIM AND METHODOLOGY Currently in Poland, wooden buildings are becoming archaic, and antique wooden buildings often lack proper care and restoration, becoming scarcer and scarcer every year (Fig.1). Hence the importance of protection, documentation and research of the buildings that still do exist, which sometimes entails protecting them against over-conservation by zealous owners. Such conservation undertakings often include restoration of façades, with unnecessary removal of antique stucco work, door and window carpentry, stairs and floors. Window carpentry was quite uniform in entire Poland, making use of similar technical solutions. However only very few original windows have survived until today, due to imperfections in production technic (which forced owners to replace them with newer ones), fashion fluctuations, but also fires, wars and the detrimental effects of the passing time. Therefore, the oldest windows preserved in Poland date back to the 18th and 19th century [Tajchman, 1990]. The aim of the research was a stocktaking of windows and corresponding decorations in antique wooden buildings from the Świdermajer style in the town of Otwock. Analysis of their style, structure, technology and material, as well as an attempt on systematic categorization of ornamental elements and motifs.

A B

C D Figure 2. New windows made in traditional style in buildings at: A- Kraszewskiego 101 (No.31), B- Lelewela 7 (No.33), C- Poetycka 5a (No.59) and D- Kościuszki 7 (No.24)

Buildings chosen for the research were taken from the list of historical heritage buildings in Otwock. They have been entered in the Regional Register of Historical Buildings quite recently: on September 13, 2017. On the basis of field visits, only 80 out of the 176 entries from the list were qualified for research (Table 1). Bricked buildings and wooden houses that could not be approached were discarded also those, whose owners did not give permission for taking photos. The buildings under research were analysed to the degree of preservation of original windows. Due to numerous replacements, a total of 97 original windows have been included in the research. We described their construction and the divisions into window lites. Additionally, we photographed and classified decorations, and prepared qualitative and quantitative collations of such elements as: shutters, window sills, cornices and batten frames.

TEST RESULTS Out of the 80 buildings under research, 74 were still inhabited, 5 were in good technical condition but empty, and only 1 building was ruined (Fig.1). Total 36 of them had all their original windows, and 23 buildings had both old and new windows. Because the buildings were inhabited by many families, there would be different sets of windows within the same building: original windows in one area, new wooden windows in another, and also plastic windows. Unfortunately, the high number of 20 houses had only modern windows, and in some cases the owners preserved the original window field divisions (Fig.2). Therefore, a total of only 97 original windows, preserved in historical wooden Świdermajer buildings in Otwock were analysed in our research. Most of them were wooden, double casement windows with lateral hinges. Such windows were very popular in Poland between 1770 and 1870 [Tajchman, 1990]. The remaining windows also had shutters, but were single rather than double, with their summer or winter wings dismantled. Considering that the houses built between 1870 and 1930 in this area had higher storeys, the height of the window usually fell between 1200 and 1400 mm [Tajchman, 1990]. Therefore, it became problematic to mount glass panes that would cover the entire casement, and windows started to be divided into two parts, with a horizontal transom moved slightly upwards [Tajchman, 1990].

A B C Figure 3. Windows with muntins above the transom A- Kołłątaja 29 (No.16), Kościuszki 7 (No.24), Słoneczna 8 (No.69)

In the preserved antique windows of wooden Świdermajers’ buildings, the transoms were also shifted upwards. Additionally, usually only in the external casements, in the transom part (Fig.3) or both above and below the transom (Fig.4) cross or vertical muntins were applied, quite densely close to each other. It was an attempt to optically reduce the size of the big glass pane, by adding a grid of mullions.

A B C Figure 4. Windows with mullions above and below the transom A- Willowa 6 (No.77), B- Świerkowa 16 (No.73), C- Mała 5 (No.37)

Out of the 97 windows that have been examined, 56 of them had an awning upper part with hinges mounted on the upper edge of the window. It's an important characteristic of Świdermajers’ architecture, because traditionally, at the turn of the 20th century, in Poland, the upper part of the window was almost always a hopper [Tajchman, 1990] (Fig.5).

A B C Figure 5. Opens with pivoting upper part: A- Samorządowa 8 (No.66), B- Bagatela 27 (No.3), C- Mickiewicza 25 (No.41)

There were very few windows with a central stile between casements, replaced in many cases by a lipping batten that covered the space where the two wings meet, which was also characteristic for this period [Tajchman, 1990]. Stiles appeared in wide windows composed of multiple parts. They could be seen in windows divided into two levels: with

89 three lites in the transom and four lites in the main part below the transom, summing up to a total of up to seven lites in a window (Fig.6A). In many buildings we documented windows divided into 5 parts, where the upper part, the transom, was made of 2 hopper windows, and the lower part, below the transom, was made of 3 casement windows, with a stile dividing the double-casement window from the single-casement one (Fig.6B).

A B Figure 6. Windows with 7 and 5

In some cases, the 6-lite windows had three casements above the transom, which opened on hinges located on the sides, just like the casements in the part below the transom (Fig.7). The height of the part below the transom was sometimes divided into two parts with horizontal muntins, one in each casement (Fig.7B).

A B Figure 7. Windows with 6 parts/lites: A- Mickiewicza 31 (No.42), B- Poetycka 21 (No.60)

Windows from that period often included small parts (“vents”) that could be opened independently to let in fresh air [Tajchman, 1990]. In the buildings under analysis, it is difficult to tell today whether they were authentic or replaced. We know for sure that in 12 double windows, one of the lites of a casement (divided with mullions into usually 3 or 4 lites) was operable (could be opened independently), allowing for room ventilation without the necessity to open the entire casement (Fig.8A and 8B). Such small ventilation openings 90

("vents") were also included in windows with multiple lites (Fit.7B). In one of the buildings we discovered a window made of two casements, each of them had three levels and each of the separate lites could be opened independently (Table 1, building No. 52, ul.Moniuszki 27). Apart from typical windows, whose transom bar was shifted upwards, we also documented 3 windows, whose casements were divided by horizontal mullions in an assymetrical way, where the bottom lite was smaller (Fig. 8C).

A B C Figure 8. Windows with "vents" (small casement parts opening independently): A- Jana Pawła 13 (No.13), B- Samorządowa 8 (No.66) and a window with mullions placed in its lower part: C- Czarnieckiego 6 (No.6)

In 8 Świdermajer buildings in Otwock, there were single-unit windows with various different division patterns of the glass pane. Most of them (a half) had two levels (the main part and the upper transom), and both parts could open by swinging on lateral hinges (Fig.9A, 9B and 9C). Two buildings had single-unit windows divided into three fields with mullions (Fig.9D).

A B C D Figure 9. Single-unit windows with transom: A- Mała 3 (No.38), B- Piaskowa (No.57), C- Poniatowskiego 11 (No.63) and a single-unit window: D- Jeremy 5 (No.14).

In many cases, single-unit windows were placed next to one another, forming a row - a wide window composed of three units (Fig.10A) or single-level windows were combined with double-level windows (Fig.10B).

A B Figure 10. A triple-unit window: single-casement window combined with a double-casement window: A- Poetycka 5 (No.59), and single-unit windows with transom with a more complex central unit: B- Andriollego 66 (No.2)

In 54 out of the 80 buildings under research, there were no decorative cornices above the windows. This were found only in 26 buildings. In most of them (9 of the buildings under research) they had the form of a small roof that was usually made of wood, but we have also found one made of metal. In some cases, below the little roof there was a frieze that could have simple ornaments (Fig.11A and 11B). In 5 cases, the cornice was made of a batten with a decorative motif of teeth, resembling antique patterns (Fig.11D) or a shape of dovetail (Fig.11C).

A B

C D Figure 11. Window cornices: A- Moniuszki 27 (No.52), B- Słoneczna 15 (No.52), C- Samorządowa 16/20 (No.68), D- Lelewela 7 (No.33)

Equally popular (found also in 5 cases) were window cornices with floral fretwork motifs used in entire Poland and Europe, inspired by the Liebold's pattern handbook, either approached with botanical precision, or simplified, as it was the case in 3 buildings (Fig.12). In 3 buildings we found more abstract patterns combining floral and geometrical designs. In 2 cases, the window cornice was made of simple battens fixed to the façade, which can be linked to the folk tradition of Eastern Republic of Poland, where windows on the shorter walls had frames imitating the frames of icons [Mikuła, 2015] (Tab.1, building No.1 ul. Andriollego 35, Fig.12E). One building had cornices with patriotic animal motifs, depicting an eagle with spread wings (Tab.1 building No. 42, Mickiewicza 31- Fig.12F). Similarly, also in one building, we found a wave-like motif, where line alternated between

92 convex and concave sections on the upper side of the batten (Tab.1, building No. 47, ul. Mickiewicza 44/50b).

A B

C D

E F Figure 12. Window cornices with floral motifs: A- Kościelna 18 (No.20), B- Kościuszki 7 (No.24), C- Mickiewicza 35 (No.44), D- Kościuszki 39 (No.30), E- Andriollego 35 (No.1), F- Mickiewicza 31 (No.42)

In rare cases, Świdermajers’ buildings in Otwock had also a decorative band below the window. Out of the 80 buildings included in the research, only 19 had such decorative strips under the windows, and 61 did not. Most of those decorations (in 11 buildings) had the form of a simple, profiled batten placed below the window. In 3 buildings, the battens had a concave-convex line on the lower part of the batten (Fig.13C). In 3 buildings, we could see richly decorated fretwork ornaments, typical of Liebold's handbook: abstract and ornamental, symmetrical patterns (Fig.13A and Fig.13B). In one building there was a typical floral motif with climbing vines (Tab.1, building 20, ul. Kościelna 18). Similarly, in one case we observed a band in the form of a reversed tympanum (Fig.13D).

A B

C D Figure 13. Bands under the windows: A- Kraszewskiego 101 (No.31), B- Kościelna 18 (PL.20), C- Żeromskiego 60/62a (No.80), D- Moniuszki 27 (No.52)

A decorative element that appeared in every building under research were window frames made of battens. Most frequently, they were painted the same colour as the window frame, sometimes a slightly darker than the window and the wall boarding, in order to highlight the window visually and make it stand out in a large, uniform and often monotonous wall covered with boarding. The frames were made of wooden battens connected with miter joints in the corners, resembling a painting frame (Fig.14). The battens could be profiled or

93 not. The profiles were simple, and combined convex and concave elements, sometimes with larger, sudden cuts, to add some diversity.

A B C Figure 14. Batten frames around windows: A- Kościelna 23 (No.22), B- Narutowicza 51 (No.55), C- (38) Mała 3 (No.38)

Another characteristic feature of Świdermajers’ architecture are shutters. They have been found in 49 out of the 80 analysed buildings (31 buildings did not have them), but probably originally there used to be more. In some cases, after replacing the windows and installing modern ones, the shutters simply did not come back to their place, which can be proved by the remaining shutter hinges. This might be due to the fact that the inhabitants did not require any additional thermal or acoustic insulation, or in some cases might be due to technical difficulties of placing wooden shutters on a plastic window frame and lack of aesthetical coherence of such an extreme combination of materials. The shutters were mounted on hinges fixed to the window frame. They were very diversified, not only considering window dimensions and field divisions, but also colours. Usually, shutters had the structure of frame and recess. Most had profiled, chamfered edges and a clearly marked central field within the recess. The shutters usually ware painted in colours corresponding to the building. Sometimes, two different colours were used to contrast the frames and recess fields. In most cases, shutters were divided into three fields (in 35 of the buildings under research), in 12 buildings there were shutters divided into two recess fields, and in only 2 buildings they had four recess fields. Shutters composed of 3 recess fields had different kinds of divisions (different field proportions). In as much as 30 buildings, the topmost and downmost fields were oriented horizontally (in 25 cases they had the shape of a square and in the remaining 5 cases, a rectangle), and the third, central field was vertically oriented (Fig.15A and 15B). Sometimes, as an additional decorative element, openings with various shapes were cut in the upper recess, eg. hearts, romboids, triangles or circles (Tab.1, building No.6 ul. Czarnieckiego 6, building No.11 ul. Gliniecka 11, building No.16 ul. Kołłątaja 29, building No.67 ul. Samorządowa 22a). In two cases, the upper recess was replaced with a jalousie doors (Tab.1 building No.72 ul. Sucha 7, building No.15 ul. Jeremy 7- Fig.15B). This triple shutter division could also have other layouts, with the central recess oriented horizontally and two vertically oriented ones on both ends. Such a solution was discovered in 3 cases: in two of them the central recess was rectangular, and in one square- shaped (Fig.15C).

Moreover, shutters could be divided into three even squares (tab. 1 building No. 73 Świerkowa 16 – Fig.15D), or with field dimensions becoming smaller towards the bottom (tab. 1 building no. 77, ul. Willowa 69).

A B C D Figure 15. Triple recess shutters: A- Kołłątaja 29 (No.16), B- Sucha 7 (No.72), C- Majowa 24 (No.36), D- Świerkowa 16 (No.73). The division of shutters into two recesses was observed in 12 buildings, as it has been mentioned above. Nine of them had even, vertical rectangles (Fig.16A). Only in 2 buildings the shutters had a square recess in the upper part and a vertically oriented, elongated rectangle below (Tab.1, building No.32, ul. Krótka 10, building No.65, ul. Reymonta 29). One of those shutters had a jalousie in the uppermost recess (Fig. 16C). In one building we found shutters that were quite different from the rest, as their structure had frames and recesses, but the recesses (two) were filled in their entire surface with little, movable, horizontal, diagonally tilted boards (Tab.1, building No.1 ul. Andriollego 35- Fig.16D). Such shutters, according to the existing terminology, are called Persian shutters or persianas [Tajchman, 1990].

A B C D Figure 16. Double-field shutters: A- Kościuszki 19 (No.26), B- Reymonta 29 (No.65), C- Krótka 10 (No.32), D- Andriollego 35 (No.1)

As it has been mentioned before, only 2 houses had shutters with 4 fields, whith the uppermost and downmost fields oriented horizontally, and the middle ones vertically (Fig.17).

A B Figure 17. Shutters with four fields: A- Narutowicza 53 (No.56), B- Moniuszki 20 (No.50)

In case of a series of three adjoining single-unit windows, their shutters had to either be wider, or - to preserve the slender proportions - another shutter unit was added. This solution was found in 9 buildings in total, 5 out of them had shutters divided into 3 fields, and 4 of them had 4 fields in each shutter unit.

A B Figure 18. Shutters with single, wide shutters on each side: A- Mała 3 (No.38), and shutters divided into with two asymmetrical casements on each side, connected with hinges: B- Lelewela 7 (No.33).

Out of these 9 buildings, 5 had shutters made of single units on each side, or in other words, each of the shutters was separate (Fig.18A), but in this case they were wider by ca. 30% (Tab.1 building No.57 ul. Piaskowa, building No.6 ul. Czarnieckiego 6, building No.38 ul. Mała 3). In 3 buildings, there was an additional casement added on each side, meaning that each shutter unit was made of a main shutter with an additional, narrower (also about 1/3 of the width) casement fixed to the main shutter (Tab.1, building No.33 ul. Lelewela 7, and

96 building No.60 ul. Poetycka 21). In one case, we observed shutters made of double-casement shutters on each side, so each shutter was made of two casements of similar width, connected to each other with hinges (Tab.1 building No.14 ul. Jaremy 5- Fig.19A). The building no. 44 at Mickiewicza 35 was an exception. It had double-casement shutters on each side, made of two casements of equal width, connected with hinges (Fig.19B).

A B Figure 19. Shutters made of two casements each, connected with hinges: A- casements of similar width, Jaremy 5 (No.14) and B- of identical width, Mickiewicza 35 (No.44)

There were very few windows that would include all of the decorative elements: cornices above windows, decorative bands below windows, batten framing and shutters (Table 1, building No. 66 ul. Samorządowa 8, building No. 18 ul. Konopnickiej 7 and building No.20 ul. Kościelna 18; see also Fig.20)

A B Figure 20. Windows with all the decorative elements: A- Samorządowa 8 (No.66), B- Kościelna 18 (No.20)

SUMMARIES AND CONCLUSIONS The research revealed that 93% of the analysed Świdermajers’ buildings in Otwock are still inhabited. Only 6% are empty, and 1% is in a ruin. This proves that the technical condition of those buildings is sufficient. However, many of the dwellers complained about very bad thermal, acoustic and humidity insulation, especially around the windows, giving examples of water pouring inside during heavy rains. A vast majority of the dwellers criticised building owners for not allowing them to replace the old windows that did not fulfill their functions anymore, as well as for the lack of proper maintenance and conservation of the buildings. Chart 1 presents the structure of different kinds of use of the buildings.

Chart 1. Structure of usage types in percentages Most (46%) buildings had original windows with typical structure for Polish windows (frame with two swinging casements and lateral hinges). Additionally, this kind also appeared in buildings where at least one family replaced their set of windows with new, plastic PCV windows (29% of the buildings). Nonetheless, an important number of buildings - as much as 26% of the buildings under research - had only modern windows. It is expected that due to the poor state of preservation, the percentage of replaced windows will grow in the upcoming years. Chart 2 presents a summary of the amount and types of windows in the wooden Świdermajers’ buildings under research.

Chart 2. Number and type of windows in the buildings under research, together with a table with percentual share of the results

The antique windows have a typical Polish structure (a casement windows formed by a frame with two swinging casements). In 58% of the cases, the windows had a complex composition, divided into three fields with a rectangular transom. Decorative cornices above the windows were not obligatory in the Świdermajer style, and they appear only in 33% of the buildings under research. The results have been definitely influenced by the fact that over a half of the buildings were erected in the interwar period, when ornaments tended to be less rich. In most cases, the cornice had the form of a little roof that protected the window against rainfall. The number and type of ornamental motifs used in the cornices above windows has been presented in Chart 3.

Chart 3. Number and types of decorative motifs above windows

Decorative bands below the windows were present in 24% of the buildings. This is almost by 10% less than in the case of cornices. This is due to the fact that this ornamental element was not very popular. It may be so also due to the period when the buildings were erected, when ornaments were less elaborate in general. The most frequent kind of decoration placed below the window was a profiled batten. The number and types of decorative bands below the windows has been presented in Chart 4:

Chart 4. Number and types of decorative motifs below windows

Shutters were one of the most popular decorative elements in antique Świdermajer buildings, and appeared in a high number of buildings (61%). They had the structure of frame

99 and recess. Quite often they had various different colours, with diverse dimensions and divisions, but triple-recess shutters were the most frequent. A summary of shutter presence in houses is shown in Chart 5 and 6.

Chart 5. Presence or lack of shutters in the buildings under research

During the replacement of original windows with new ones, shutters were often removed, which is confirmed by the presence of hinges left in the window frames. However, in most cases, in spite of window replacement with modern ones, many original shutters still remain.

Chart 6. Types of division of shutter panels:

The presence and absence of shutters in original and replaced windows has been indicated in Chart 7. We can see that even in cases where all the windows in a building were

100 replaced with new ones, in most of them (60%) the original shutters were left intact. In 31% of the buildings that still have antique window carpentry, there are no shutters (they have been preserved in 69% of the buildings). In buildings where the original windows have been only partially preserved, roughly a half of them still have the original shutters (they have been preserved in 52% of the buildings).

Chart 7. Presence and absence of shutters in original and replaced windows

The decorative element that characterises a 100% of Świdermajers’ buildings is an additional framing made of battens around the windows. This element is present in every house included in the research. The framing usually had a darker colour than the window itself, providing a nice visual highlight on the façade.

Chart 8. Percentual share of each kind of window ornaments. The chart does not include the batten framing, whose presence was observed in 100% of the cases - in all 80 buildings under research.

A collation of the decorative window motifs in antique wooden Świdermajers’ buildings shows that there was an equal number of buildings without any decorations, as those with

101 shutters as an ornament (23 houses in each case). This proves that the windows were not richly ornamented or the original ornaments did not survive until today. A quantitative comparison of different kinds of window ornaments shows that shutters are the most frequent. In 11 cases, buildings were ornamented with both shutters and cornices above the windows. Windows with a full range of decorations were observed in only 8 of the buildings. The second largest set of decorations were buildings that had both shutters and decorative bands below the windows. Four buildings had only cornices as decoration. Three houses had decorations both underneath and above the windows. There was one building whose only ornament was the band below the window. Chart 8 presents the percentual share of each kind of decorative element. More and more wooden Świdermajers’ buildings face the risk of collapsing or burn in fires. Sometimes, the fire is set deliberately, because the ground where the buildings stand is very attractive and tempts new investors. On the other hand, more and more newly erected, contemporary buildings include ornaments inspired by the characteristic Świdermajers’ style. Some newly erected buildings have those characteristic wooden verandas. Entire residential estates are built, but unfortunately the ornaments are not handcrafted. Nonetheless, it becomes clearly visible that people draw inspiration from the traditional style, including its decorative motifs.

REFERENCES

1. CICHY A., 2007: Znaczenie ozdobnego deskowania w periodyzacji drewnianej architektury w pasmie otwockim. Problematyka badawcza i konserwatorska, Ochrona Zabytków nr 3, s.35-58. 2. LEWANDOWSKI R., 2012: Twórcy stylu „Świdermajer”, Józefów 2012. 3. MIKUŁA R., 2015: Tradycyjne zdobnictwo drewnianych chałup podlaskich w gminie Bielsk Podlaski, Praca inżynierska na kierunku - Technologia drewna wykonana pod kierunkiem dr inż. Piotra Mańkowskiego, Warszawa. 4. RADOMSKA A., 2001: Architektura drewnianych ośrodków podwarszawskich, s.94- 116, [w:] Dziedzictwo kulturowe Mazowsza, red. Brzeziński W., Sołtysiak M., Warszawa. 5. RUSZCZYK G., 2007: Drewno i architektura. Dzieje budownictwa drewnianego w Polsce, Warszawa. 6. TAJCHMAN J., 1990: Stolarka okienna w Polsce, Warszawa.

Streszczenie: Tradycyjne zdobnictwo okien budynków w stylu świdermajer w miejscowości Otwock. W artykule dokonano analizy okien w zabytkowych budynkach drewnianych utrzymanych w stylu świdermajer, położonych w miejscowości Otwock. Ujawniono, iż wiele z nich zostało już wymienionych na nowe. Zwrócono uwagę na ościeżnicową konstrukcje okien zabytkowych oraz podział pola otworu okiennego na podślemię i nadślemię, dodatkowo rozczłonkowane krzyżowymi lub pionowymi szczeblinami. Przeanalizowane zostały tradycyjne elementy zdobnicze stolarki okiennej takie jak: nadokienniki, podokienniki, ramy okienne i okiennice oraz ich klasyfikacja ze względu na występujące motywy.

Słowa kluczowe: architektura drewniana, okno, Świdermajer, Otwock, zdobnictwo

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Corresponding author:

Anna Rozanska Department of Technology and Entrepreneurship in Wood Industry Institute of Wood Sciences and Furniture, Warsaw University of Life Sciences – SGGW, Ul. Nowoursynowska 159, 02-776 Warsaw, Poland e-mail: [email protected]

ORCID ID: Rożańska Anna 0000-0003-1865-3571 Beer Piotr 0000-0002-2906-1208

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Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 104-114 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Use of wood in the Baltic courses architecture on the example of Binz in Ruges

DARIA BRĘCZEWSKA-KULESZA1, GRZEGORZ WIELOCH2 1University of Science and Technology, Faculty of Civil and Environmental Engineering and Architecture, Architecture Department Bydgoszcz, Poland, 2University of Life Science, SGGW, Faculty of Wood Technology, Warsaw, Poland.

Abstract: Use of wood in the Baltic courses architecture on the example of Binz in Ruges. The town of Binz is a great example of a comprehensive renovation of a town built in a spa style using wood. Made of wood, balconies, loggias, porches, gables, half-timbered constructions of fragments or even entire floors of buildings, combined with various architectural elements, referring to different stylistic formations, creates a perfectly matching conglomerate of forms despite each other's diversity and the surrounding nature. Thanks to the forms of decoration used, the frontage of the building looks harmonious. Laurel ornaments give them a specific beauty that allows you to break away from reality and encourages relaxation. Accents in the landscape, especially variety of villas, prevent fatigue and add expression to the whole building giving desire to just watch them. However, without the use of wood usually painted white, this would never have been achieved. That is why they were often called "white pearls of the Baltic".

Keywords: resort architecture, wood, balconies, loggias. verandas. ornaments

INTRODUCTION Baltic resorts both in Poland and with our neighbors are very popular among tourists. Unfortunately, many of these once charming towns have lost their former character and beauty. Oftenly beeing irretrievably destroyed by ill-considered mega- hotels investments, building density and architecture introducing dissonance in space. Fortunately, there are still resorts that managed to preserve the vintige climate, harmony of idyllic architecture that fits into the landscape, thanks to the use of wood for building, finishing and decorating buildings. One of them Figure 1. Location of the resort of Binz on the island of Rügen is Binz in Rügen (GERMANY) - a "white, lacy" town, with unusual, almost ephemeral architecture and perfect fit with nature.

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Figure 2 View of the resort of Binz from the sea

CREATION OF SUPER-BALTIC COURSES Socio - economic changes that took place in the nineteenth century, initiated, inter alia, the fashion for rest in the fresh air, in contact with nature. Thanks to the rapid development of railway networks, the time needed to reach even quite distant places has been significantly reduced, and the journey has become cheaper. The development of industry, mass production of cheap goods, influenced the increase in the standard of living of a large part of society. The nineteenth century was also a period of medical development. Among other things, climate treatment was introduced, and the value of fresh air and sea baths began to be appreciated. Thanks to this, seaside towns were becoming more and more popular, they were slowly transforming from fishing villages into elegant, seaside resorts.

Figure 3. View of the resort buildings in Binz and the seaside promenade. The white color of buildings dominates.

The first German Baltic seaside resort was founded in 1791 in Heiligendamm. Mostly German and European aristocrats and rich industrialists came there. The resort was built of white buildings in the style of classicism, located on the seaside promenade [Rochov, Havermann 1993] The first resort in Pomerania, founded on the island of Rügen in 1810, was Putbus-Lauterbach. In the following years more resorts were created, such as Binz that took its origin from a fishing village.

SEA COURSES ARCHITECTURE The architecture of seaside resorts is a very wide group of buildings with various stylistic and formal features, various sizes and shapes of solids. Landscape include hotels,

105 guesthouses, villas for accommodating guests as well as sports facilities, concert halls, piers, restaurants and many more connected especially by location and adjustment to natural conditions. Their style is so characteristic that it even has its own architectural term Bäderarchitektur - a resort architecture that is typical of the northern coast of Germany. Resorts were built in undeveloped terrain, often near fishing villages, on the sea shore, i.e. in a place that has direct contact with exuberant nature. They were established along the beach forcing linear layout of the village. The sea has become an important factor in urban composition. The proximity of picturesque nature was not without influence on the diversity of architectural forms of resorts. Starting with classicism the spa architecture developed using all the historical forms popular in the nineteenth century, moving to new fashionable styles at the turn of the century. Introducing “Art Nouveau” or various forms of picturesque architecture. The peculiarity of the architecture of the Baltic resorts is the successful combination of various stylistic forms incorporated into the coastal landscape. In the 19th century resorts, relatively small, several storey buildings were erected. Facades were enriched with balconies, loggias, breaks, gables and verandas. To make these elements, wood was eagerly used, which was relatively low- priced and convenient to process, and also blended well with the coastal landscape. Whole wooden houses were made as prefabricated elements were already used in the second half of the century [Omilanowska 2011]. Baltic resorts are often called "white pearls" as a result of the dominant facades colors. Most often, facades, both plastered and wooden as well as architectural details were painted white. In addition, bright colors were used, e.g. olive, beige or blue-gray. The multitude of wooden loggias, balconies, breaks, verandas, gables decorated with intricate patterns carved in wooden panels makes buildings, even large ones, look elegant and delicate.

WOOD IN THE SPA ARCHITECTURE The popularity of wood as a building material in Germany has a long tradition dating back to the Middle Ages. Half-timbered constructions were most often used, with exposed beams forming decorative patterns bearing woodcarving decorations. In the nineteenth century, the popularity of wooden architecture increased and took on another meaning. It was caused by a number of factors such as tourism development, world exhibitions, searching for national styles, economical aspect and finally the availability of samples and prefabricated elements. Traveling to Italy via the Alps, fashionable in the 'upper realms' since the mid-18th century, is associated with the popularity of the 'Swiss style'. In wooden architecture the so- called „Swiss house" was adopted, inspired by traditional Alpine architecture [Gubler 1979]. This trend was usually associated with local traditions, which brought different forms depending on the region [Tarnawski 2012]. The search for national styles prompted architects to become interested in folk architecture. Especially the vision of Russian national architecture with its woodcarving decorations resembling lace has gained great popularity. Decorations of residential buildings in the former eastern territories of Poland corresponded with it [Gaweł 2010]. The project propagated thanks to industry publications, also gained popularity in Prussia [Szewczyk 2006]. An important role in the promotion of national styles was played by world or regional exhibitions, where wooden pavilions with native features were eagerly erected being cheaper, quick to install and easy to transport. In 1867, the design of a wooden summer villa was shown at the world exhibition in Paris what greatly popularized this specific type of building architecture. Wooden houses with columns, verandas, balconies with "lace" decor have become fashionable. The high availability of various types of architectural patterns and ornaments, company catalogs and construction handbooks also contributed to the

106 popularization of wooden architecture and wooden architectural details [Liebold 1893]. Over the course of time, a peculiar mix of various elements was created, a conglomerate of designs and templates, which was widely used in resort construction, creating picturesque and decorative, yet light in reception and perfectly blending with the sea and dune vegetation architecture [Bręczewska-Kulesza, Wieloch 2018].

WOODEN ARCHITECTURE IN BINZ A beautiful, well-preserved example of a "white town" with facades enclosed by rows of loggias and verandas, kept to this day in a consistent style is the resort of Binz in Rügen. Year 1870, 80 guests stayed in Binz, and only five years later their number increased to 500. Consequently the rural cottages expanded by adding wooden verandas and porches. New buildings were erected next to Strandpromenade running along the beach. In 1880, Wilhelm Klünder built the Strandhotel as the first hotel near the beach. The largest increase in buildings number was between 1890 and 1910 [Verordnung 2002]. Villas and guesthouses, most of which were intended only for summer holidays, took fashionable and representative forms. Under the influence of fashion on picturesqueness architecture, spas and growing health awareness that fresh sea air has a positive effect on the human body, so-called resort architecture was developed. Main features for this style are open loggias, balconies and porches made of wood covering massive facades. Lumps of buildings, especially villas, were often additionally enriched with breaks, bay windows, ridge ornaments, towers and attics. On the wave of fashion for 'picturesqueness', as well as for economic reasons, also half-timbered constructions, wooden architectural elements and decorations were used in Binz, which gave the buildings an 'idyllic' character. In most houses, both picturesque villas and buildings with simple, cubic blocks, enriched with elements made of wood, with a characteristic decoration of numerous ornaments made of laubzega1.

Figure 4. Porches and balconies of wooden structure filled with openwork panels Murkanerstrasse 1

1 1 The form of decoration was created by cutting out the ornament with a thin saw in boards, placed in the tops of buildings, porches, as a support at the remnants of purlin beams, sometimes window frames, under and window panels. It did not require complicated technology, only the fantasy and precision of the contractor, and was used in both wooden and brick buildings. - In search of the lost tradition of construction, Work. coll., Nowy Dwór Gdański, 2009, pp. 49-50. In other regions of Poland it was called an openwork or lace.

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What is noticeable and dominant in Binzs’ architecture are wide wooden verandas, less often balconies or loggias, arranged in very different configurations. Often spread over the entire width of the façade or on other walls, on the sides on both sides or on one, on the corners, between breaks or endearing break. Most create multi-storey divisions with a separate roof on the last floor. The skeletal structure of the verandas is based on columns and beams forming the frame of the veranda, supported between floors by the ceiling beams. Swords and decorative forms of braces were often used. Between them, in the window areas and above the javelins, panels cut out with lace patterns were placed in the brackets. Wooden elements were painted in bright colors, usually white often giving freshness and cleanliness of the environment Fig. 5. A large part of the porches were originally open however currently some are glazed. After World War II, due to the lack of apartments in the destroyed cities, refugees came to Binz and the buildings were adapted for year- round use, which meant a lot of renovations. The decorative panels cut out in various patterns were used Figure 5. Decorative window zone villa on Margaretschof in two ways, either by putting on a Ozdobna strefa podokienna willa na smooth background from a wooden boardMargaretschof or boards to make contact, or by placing them apart, thanks to which the light shone through them. Both ways caused a specific play of light and shadow. Probably due to climatic reasons, the veranda under the windows, balustrades of balconies and loggias were more built-up. Decoratively cut boards, placed vertically on a full background or less often alone.

Figure 6. Construction of balconies and decorative panels in Villa Meeresgruss on Marienstrasse1

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Boards were cut into modest patterns in the form of small circles, hearts, ovals, tears, stylized motifs of lilies, crosses. Sometimes boards were cut in the form of flat balusters, then the background was not underlay. (Fig. 5). Concavities were cut at the edges of the boards and shaped into longitudinal teardrops, only the arched ends were cut out or balusters in the form of posts were used. The number of patterns was very diverse, most of the buildings had their own style consistently applied throughout the entire building.

Figure 7. The gable decoration is made of boards with a decorative motif

In the upper zone under the javelin in open constructions or above the glazed windows, decorative panels with laubzeg ornament were used, with glazing placed on the background of a wooden board. Here, too, each building had its own, consistently applied theme. A conglomerate of various forms, both plant and geometric, was used. Most probably inspiration came from both Renaissance and Art Nouveau.

Fig.8. Window decoration

Some designs resemble stylized ferrule or arabesque ornaments, others are based on circles, squares with curving lines and flowers. The decorations filled every free space between beams and columns. Thus giving the facades lightness that attracted attention from a distance.

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A much simpler solution was to use instead of decorative panels, decorations in the form of stylized swords, braces and ridge ornaments, ending in spherical forms. As such, they required an appropriately decorative setting. On the other hand, the buildings, viewed from the beach, pier or sea, were to be a showcase of the resort, to attract the attention of potential patients.

Figure 9 i 10. Openwork decorative panels Figure 11. Wooden balcony with decorations

Despite the large variety of forms, enriched with rows of multi-storey verandas and loggias or balconies, all decorated with intricate patterns carved in wooden panels, the guest houses look very coherent and harmonious. (Fig. 3, 14). Among them are also projects showing the stylistic pluralism of nineteenth-century resort architecture. In terms of functionality, loggias and verandas were an extension of peace, they were a link with the surrounding nature, places where not only one could take fresh air comfortably resting on a sun lounger, but also especially in buildings located on the seafront promenade watch what was happening outside. They were the equivalent of theater lodges, where the stage was a promenade with a continuous "spectacle" played by walking holiday makers, and the decoration of the sea and dune vegetation. As such, they required an appropriately decorative setting. The architecture of Binz seems to be dominated by white buildings with facades enriched by rows of multi-storey verandas and loggias (Fig.14), but among them there are also projects showing the stylistic pluralism of 19th-century resort architecture. These are objects that formally correspond to various styles popular in the nineteenth and early twentieth centuries, among which there are several implementations evoking fashionable trends in wooden architecture. Three outstanding objects must be mentioned. They are buildings made in various construction techniques, referring to various stylistic forms. Their architecture is characterized by a subtle form, darker or more vivid colors and a greater diversity of architectural elements.

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The first of them, built in 1890, is the Villa Undine at Strandpromenade 30, near the spa house (Kurhaus) and was commissioned by Countess von Münster and was her private residence. [Omilanowska 2011]. The building is also very interesting for technical reasons, as an early example of finished houses, transported in parts and assembled on site.The villa was built from prefabricated elements produced by Wolgaster Actien-Gesellschaft für Holzbearbeitung, in the technology of a wooden skeleton filled with boards. The house was presented in the company's catalog from 1892. The villa is distinguished by picturesque architecture, asymmetrical, fragmented structure of the body with a tower topped with a helmet, a veranda founded on a half-10-side plan, a break with a high triangular gable, smaller verandas and balconies and outbuildings. All elements of the block were covered with separate, gable roofs. The whole was painted in a dark burgundy color with which white window and door joinery as well as decorative elements of the gables were contrasted.

Figure 12. Willa Undine

Second - a little further east, also on the seafront promenade, is the villa "Quisisana" (Strandpromenade 15) built in the same year. The upper part of the building is a half-timbered structure, "erected" on a lightly plastered ground floor. Originally, the light plaster of the ground floor was contrasted with the brick filling of the half-timbered wall. After renovation, the filling has been plastered. The block of the building was founded on the plan of the letter "T", strongly fragmented, and accented by a tower with a spire located in the middle. The villa is enriched with wooden wide verandas, decorated with a modest laubzeg ornament and what distinguishes this object is the exposed half-timbered structure. The house was the private apartment of a government official, Dr. Victor von Koerber, district administrator in Bergen auf Rügen and his wife. The house was rebuilt in 1929 and the owners, von Koerber, ran a guest house here [Finke, Pippia 2009]. Third - in the neighborhood of the Undine villa, on the west side, the house in the so-called Swiss style - Villa Ruscha, built in 1896 [Finke, Pippia 2009] is noteworthy.

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In the second half of the nineteenth century, via competitions on Swiss national architecture (the first in 1852), world exhibitions in Paris from 1876 and Vienna in 1873. The Swiss style was even more popularized and took over many foreign patterns. However lost its original authenticity, becoming “the most universal and cosmopolitan style of wooden architecture” [Wojciechowski 1953]. As such it was widely used in various forms, e.g. combined with neostyle. Also, the Ruscha villa is not a building corresponding to the style of the houses from the Berne Pass. but it refers to the vision of such a household, transformed by a number of further solutions.

Figure 13. Willa „Quisisana“ (Strandpromenade 15).

Figure 14. Villa Ruscha, Strandpromenade 31 112

The villa refers to the style of Alpine architecture through wide, supported by woodcarving brackets, balconies, a massive gable roof with a highly eaves, and "lace" decorations. A foreign element is the use of delicate, decorative metal grilles on the balconies (currently only in the central balcony of the facade) and the gray-blue colors of the villa are a counterweight to the rustic style, contrasted with the white frames of the window frames. Universal elements are numerous bay windows, projections covered with separate roofs, which increases the expression of the body and gives the building lightness. The house was built as a guest house with 15 comfortably furnished rooms.

CONCLUSION The wood worked perfectly in resort architecture. Balconies, loggias, porches, gables, half-timbered constructions of fragments or entire floors of buildings made out of wood and combined with various architectural elements, referring to different stylistic formations, creates a perfect conglomerate of forms, matched despite each other's diversity and the surrounding nature. Binz is a great example of a comprehensive renovation of the city, thanks to which it has retained its original resort character. Thanks to the unified forms of decoration, the frontage of the buildings look harmonious, and the laurel ornaments give them artistry, which allows them to break away from reality and encourage rest. Accents in the form of villas with different forms prevent fatigue and add expression to the whole surrounding. However, without the use of wood, this would never have been achieved. This can be seen, for example, when looking at Binz photographs from the GDR period, where many houses were damaged, some of them lacked wooden elements. Today, after a comprehensive renovation or even after rebuilding, the eyes of crowds of tourists eagerly visiting Binz enjoy it.

Streszczenie: Wykorzystanie drewna w architekturze kurortów nadbałtyckich na przykładzie miasta Binz w Rugii. W artykule omówiono rolę drewna w architekturze kurortowej na przykładzie miasta Binz w Rugii. Dzięki pieczołowitej renowacji oraz odtworzeniu detalu budynków w Binz udało się zachować dawny klimat, harmonię sielankowej architektury zgodnej z naturą, dzięki zastosowaniu drewna do budowy czy wykończenia i elementów dekoracyjnych budynków. Binz jest świetnym przykładem dużego znaczenia drewna, jako materiału o szerokim zastosowaniu w architekturze kurortowej, niezależnie od ogólnej stylistyki budynków. Problematyka została omówiona na tle zagadnień dotyczących popularyzacji architektury drewnianej i stylów narodowych w XIX stuleciu.

REFERENCES 1. BRADFORD LANDAU S., 1983: Richard Morris Hunt, the Continental Picturesque, and the „Stick Style“, “The Journal of the Society of Architectural Historians” 42, 272–289. 2. BRĘCZEWSKA-KULESZA D., WIELOCH G., 2018: Wooden werands in Gdańsk - Oliwa construction. Annals of Warsaw University of life sciences. Forestry and Wood technology nr 100, 3. FARIN A., 2012: Lauterbach. Rügens ältestes Seebad. Hafenort. Bootsbautradition, Farin Andre, Lauterbach 4. FINKE B., PIPPIA B., 2009: Landhäuser & Villen am Meer - Rügen und Hiddensee, Culturcon Medien, Berlin 5. GAWEŁ A. 2010: Zdobnictwo drewnianych domów na białostocczyźnie . Orthodruk. 6. GUBLER H.M., 1979: Ein berner Bauernhaus für den König von Württemberg : eine Miszelle zum "Schweizerhaus" und seiner Entwicklung 1780-1850, „Unsere Kunstdenkmäler : Mitteilungsblatt für die Mitglieder der Gesellschaft für

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Schweizerische“ t. (R.): 30 (1979), Heft 4 (http://doi.org/10.5169/seals-393350, (access 03.09.2019) 7. LIEBOLD B., 1893: Budownictwo drzewne. Wzornik detalu snycerskiego, Holzminden (reprint Wydawnictwo Górnolesie, 2009). 8. NAWROCKI K., 1996: Norweski styl narodowy w krajobrazie Obojga Prus [w:] Architektura współczesna w środowisku historycznym. red. R. MIKIELEWICZ, Łódź, s. 27–38. 9. OMILANOWSKA M., 2009: Cesarz Wilhelm II1 jego inicjatywy architektoniczne na wschodnich rubieżach Cesarstwa Niemieckiego, [in:] Pilecka E. red., Sztuka w kręgu władzy: materiały LVII Ogólnopolskiej Sesji Naukowej Stowarzyszenia Historyków Sztuki, Warszawa, s. 245-266. 10. OMILANOWSKA M., 2011: Die Holzarchitektur der Ostseebäder und die Wolgaster Actien-Gesellschaft [in:] Stadtfluchten / Ucieczki z miasta. Das gemeinsame Kulturerbe – Wspólne Dziedzictwo, Redaktor serii M. Omilanowska, Band VII / Tom VII, Instytut Sztuki Polskiej Akademii Nauk, Warszawa, s. 129 – 145. 11. ROCHOV F., HAVERMANN K., 1993: Bad Doberan - Heiligendamm, Droste Verlag, Schadow-Arkaden. 12. SZEWCZYK J., 2006: Regionalizm w teorii i praktyce architektonicznej, Teka Kom. Arch. Urb. Stud. Krajobr. – OL PAN, 2006, 96-109. 13. TARNAWSKI J., 2012 Styl alpejski w środkowej Europie i polska kontrakcja wobec niego – styl zakopiański, „Estetyka i Krytyka”, 25 (2/2012), s. 231 – 245. 14. Verordnung über den Denkmalbereich Hauptstraße I-Strandpromende Putbuser Straße - Bahnhofstraße im Ostseebad Binz, 2002, https://www.lk-vr.de/media/custom /3034_795_1.PDF?1560416845 (access) 15.08.2019) 15. WOJCIECHOWSKI A., 1953: Elementy sztuki ludowej w polskim przemyśle artystycznym XIX i XX wieku, [w:] Studia z Historii Sztuki Polskiej II. (red.) K. Piwocki. Zakł. Narod. im. Ossolińskich, Wrocław. 16. WOLGASTER ACTIEN-GESELLSCHAFT FÜR HOLZBEARBEITUNG vorm. J. Heinr. Kraeft: Import amerikan. Hölzer; Bau v. zerlegbaren Holzhäusern [...]. Wolgast [1892].

Corresponding author: Daria Bręczewska-Kulesza University of Science and Technology, Faculty of Civil and Environmental Engineering and Architecture, Architecture Department Bydgoszcz, Poland

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Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 115-123 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Wood fibreboard paraffin hydrophobization and the impact of this treatment on the board surface finishing quality

JOZEF KÚDELA Department of Wood Science, Faculty of Wood Sciences and Technology, Technical University in Zvolen, Slovak Republic

Abstract: Wood fibreboard paraffin hydrophobization and the impact of this treatment on the board surface finishing quality. The aim of this paper is to analyse the causes of surface treatment defects in commercially produced wood fibreboards (FB). The analysis of: the obtained (measured and calculated) thermodynamic characteristics and of the results of microscopic examinations demonstrated that the excessive FB hydrophobization with paraffin may cause the paraffin to release from the FB surface and to migrate into the first primer layer. For the sanded FBs, similar paraffin migration was also observed into the second primer layer. This entailed lowered drying rate for the coating materials applied on FB, lower adhesion of the coating materials to the substrate and also lower adhesion between the particular coating layers applied. At the same time, the occurring frequency of surface treatment defects increased.

Keywords: fibreboards, paraffin, surface treatment, coating materials, paint drying, thermodynamic characteristics

INTRODUCTION Agglomerated materials, fibreboards (FB) included, exhibit considerable thickness swelling. This swelling enhances surface roughness, declines mechanical performance and increases element warping. Warping originated due to non-uniform swelling/shrinkage in agglomerated materials entail also negative consequences for construction elements manufactured from these materials (SUCHSLAND 2004). To improve water repellence and to reduce swelling in agglomerated materials, the producers admix paraffin as an additive substance. The degree of wood material hydrophobization with paraffin and the related wood performance modifications depend on the paraffin amount, type and form as well as on the application mode into the wood substrate (ŠTEFKA 2002, ROFFAEL et al. 2005, GARAI et al. 2005, TORKAMAN 2008, CAI et al. 2016). The surface finishing of agglomerated materials with coatings, however, may worsen their surface treatment quality, as the result of increasing defects occurrence and of failing certain performance aspects. LIPTÁKOVÁ and KÚDELA (1997) suggest that the above-listed problems arise due to the presence of hydrophobic admixtures (e.g. paraffin) in the related materials. Authors suggest that the water-repelling substances is a probable cause of surface properties modifications in wood materials. This may have negative impacts on the coating materials adhesion to the substrate. The application of solvent-based coating materials may also cause paraffin migration into the coating layer, compel paraffin to migrate towards the dry coating surface, and lower, in this way, the drying rate of the coating. Similar problems to the above mentioned were observed during surface treatment of hard fibreboard doors. This coating substance application onto the fibreboard surface resulted in repetitive occurrence of defects such as: non-uniform coating spreading across the surface, origination of cracks and splits or the coating separation from the substrate. The aim of this paper was to assess the surface treatment quality of these fibreboards. The assessment criteria were: occurrence of defects and performance modifications. At the same time analysis of underlying causes of observed manifestations. Thermos-dynamic characteristics was also assessed - for confirmation or rejection of paraffin presence on FB surface as well as for penetration through the coating layers.

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MATERIALS AND METHODS Surface treatment quality assessment in wood fibreboards The surface treatment quality was assessed based on the defects generated and on the coating material drying. The surface treatment defects were assessed on the particular products manufactured of a commercially produced wood fibreboard. For the surface finishing a coating system was applied composing of three layers – two being a solvent-based primer and the third a two-component synthetic enamel. The drying degrees 1 and 5 of the coating material applied on FB were determined following the standard STN 67 3052. The drying rate of the coating material was compared with the drying rate of the same material applied on glass substrate. Determining surface free energy values for FBs and for coatings The paraffin presence on FB surface and paraffin penetration through the coating layers were assessed based on comparing the surface free energy values before and after the application of the particular coating layers. These results were also compared with the surface free energy values obtained with dried coating substances applied on glass substrate. The FB thermodynamic performance was investigated on five study sets, each representing ten specimens, with dimensions of 20  50  h mm. Two testing sets were without coating, the first containing specimen with the original and the second with sanded surface. The third set represented specimen coated with one layer of the primer, the fourth specimen coated with two layers of the primer and the last, fifth set consisted of specimens covered with the complete coating system: two primer layers and the finishing enamel. Contact angles were measured with testing liquid, and then the corresponding thermodynamic characteristics were derived (surface free energy and its components). The contact angles were measured with a goniometer Krüss DSA30 Standard. The measuring liquid was redistilled water. The water drops, each with a volume of 0.0018 ml, were applied onto the substrate and then their profile development was scanned with a camera. The moment of turning the advancing contact angle to the receding one was determined with the method proposed in (LIPTÁKOVÁ and KÚDELA (1994). The contact angle value associated with this moment has been declared as an „equilibrium“ contact angle. Measurements of the contact moment and the equilibrium contact angle values were used for obtaining the contact values for ideally smooth surface. This angle was subsequently used for calculating the values of surface free energy and its components. The FB surface free energy was calculated d p according to NEUMANN et. al. (1974), the disperse and polar component, S and S , according to KLOUBEK (1974). The surface free energy values for solid coatings applied on FBs and on glass were derived with using the related equilibrium contact angle values ( LIPTÁKOVÁ and KÚDELA 2002). The calculation procedure was the same as in the former case. Evaluation of the interactions at the interface FB –solid coating and solid coating – solid coating The interactions between FB surface and solid coatings or between two solid coatings were investigated with focus on interactions between the unsaturated force fields across these phase boundaries. The coating adhesion to the substrate and the compatibility of the particular layers in the coating system were evaluated based on the values of phase energy S1S2 and the values of adhesion work calculated from the experimentally obtained values of the disperse and polar components of surface free energy. The surface free energy at the interface between two solid materials was calculated according to the equation 2 2 d d p p  S1S 2    S1   S 2     S1   S 2  (1) and the adhesion work Wa of the solid coating to the substrate according to the equation

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d d p p Wa  2  S1 S 2  2  S1 S 2 (2) Calculations for surface free energy values were also done for the primer and for the synthetic two-component finishing enamel applied on glass substrate. The surface free energy was also specified for the free film reverse sides. Subsequently, there was derived the coating´s cohesion work Wc as the twofold surface energy values determined for free films according to the equation

Wc = 2S (3) and coefficient S according to the equation

S = Wa – Wc (4) RESULTS AND DISCUSSION Surface treatment defects in wood fibreboards The FB surface covered with the first layer of the primer exhibited local spots in which the coating material had not been dried to the appropriate degree. a) b)

c) d)

Figure 1. Observed surface treatment defects in FBs. a) orange peel, b) bordered patch (crater), c) wrinkled surface, d) cracking and peeling of the solid coating

This had negative impacts during application of the subsequent coating layers – which is a typical phenomenon occurring during coating material application, primarily in automated processing. At these spots, the adhesion between the coating and substrate was impaired. Thus resulting in a variety of other defects, including those related to external look (orange peel, bordered patches, wrinkled surface, cracks generation in dried coating, and similar) – Fig. 1. Experimental measurements results of the primer drying on the FB surface and on glass are summarised in Table 1.

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Table 1. Primer drying on glass and on FBs. Substrate Drying time [min.] 1. degree 5. degree Glass 10 13 FB original 12 23 FB sanded 14 26

The table demonstrates that more time was necessary to reach the drying degrees 1 and 5 on FBs than on glass. Comparing original and sanded FBs, the sanded ones exhibited worse results. The values for the 5-th drying degree were in accord with the common commercial standards set for the coating material quality; the observed facts, however, did not allow to ignore problems arising in operating conditions. Namely, it was natural to assume more paraffin migration due to higher temperatures during the coating application and drying. It is probable that the just applied coating layer has not been cured appropriately before applying second layer. This may be a potential cause of the discussed surface treatment defects.

Surface free energy The experimental results related to surface free energy were evaluated focusing on finding out whether the surface free energy values exhibited significant differences between the coatings applied on FBs and on glass. If yes, the slower drying rate and subsequently originated defects might be expected due to the presence of hydrophobic substances (paraffin in our case) admixed into wood. These substances dissolve in the coating and then penetrate through the coating layers. In the opposite case, the paraffin should not be considered as the causal agent of the observable defects. The values of surface free energy and its polar and disperse components for FBs without mechanical pretreat-ment and for FBs with applied coatings are in Tables 2 and 3. Tables 2 and 3 summarise the additive character of the FB surface free energy. The energy values were low, the disperse component was dominant. The high variability reflects the inhomogeneous FB surface. The differences between the original and sanded FBs were not confirmed statistically significant. These values are lower by about 50 % compared with the corresponding values obtained for beech wood, using the same method (KÚDELA and LIPTÁKOVÁ 2006, KÚDELA et al 2016).

Table 2. Surface free energy of FBs without mechanical pre-treatment (sanding): uncoated boards and boards coated with particular coating layers (n = 60). Surface free energy and its components Specimen number Surface treatment [mJm2] d p S1 S1 S1 35.30 29.04 6.26 1 Original FB (4.16) (1.62) (2.67) 37.61 30.15 7.46 2 Primer 1 (2.75) (0.77) (1.99) 46.31 31.13 15.18 3 Primer 2 (5.19) (0.50) (5.31) 40.57 31.04 9.52 4 Primer 2 + finishing enamel 1 (2.37) (0.55) (1.3) The figures in bold are for the arithmetic mean values, the figures in parentheses represent standard deviations. This holds also for the following tables.

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Table 3. Surface free energy of sanded PBs: uncoated boards and boards coated with particular coating layers (n = 60). Surface free energy and its components [mJm2]] Specimen number Surface treatment d p S2 S2 S3 36.33 29.18 7.15 1 Original FB (5.56) (1.97) (3.73) 36.75 29.74 7.01 2 Primer 1 (3.42) (1.04) (7.01) 39.16 30.46 8.70 3 Primer 2 (3.90) (0.81) (3.17) 40.74 30.82 9.92 4 Primer 2 + finishing enamel 1 (4.04) (0.73) (3.38)

In the case of original fibreboards, not subject to sanding, the application of one layer of the primer on the FB surface resulted only in small changes in the surface free energy values. In the case of the sanded boards, no surface free energy changes were detectable. After the application of the first coating layer, the FB surface free energy maintains its prevailing non-polar characteristics. The results obtained for fibreboards differed significantly from the results obtained with films applied on glass and even bigger differences were obtained by comparison with free films in which the energy was assessed on their reverse side (Table 4). These differences are summarised in Table 4. The table presents that these differences are generated due to chemical composition of these coatings, varying through their thickness during the drying, in relation to orientation of the molecules at the phase boundary between the coating and the substrate. The obtained results concerning the phase-boundary-related energy show that the first application of the primer initiated considerable migration of paraffin from the substrate surface into the coating - up to the coating surface. Paraffin accumulated on the applied coating layer could cause difficulties with application and drying of the subsequent layers – also in the case when the first layer had been already cured. Table 4. Surface free energy values for free films and coatings applied on glass (n = 60). Surface free energy and its components Substrate Coating [mJm2] d p N N N Primer 54.8 30.1 24.7 Free film Finishing enamel 57.1 29.5 27.3 Primer 48.73 30.99 17.14 (5.3) (0.75) (5.98) Finishing enamel 44.65 30.73 13.92 Glass (6.85) (0.65) (6.92) Primer + finishing enamel 40.57 31.04 9.58 (2.37) (0.55) (1.89) The application of the second primer layer increased the surface free energy values. This growth was more evident in the case of the non-sanded FBs exhibiting surface free energy values close to the values obtained with a standard coating on glass (Table 4). Simultaneously the surface polarity also significantly increased. In the case of the sanded board, both the surface free energy and the surface polarity exhibited only a slight increase compared to the values obtained with the coating applied at one layer. These results confirm that the application of the second coating layer caused paraffin migration into the wet coating on the surface of the sanded fibreboards. In all the three tested variants, the application of the synthetic two-component enamel resulted in the same surface properties of the complete coating system. The differences between the arithmetical means were not significant. We may state that the application of the finishing

119 synthetic enamel inhibited the paraffin penetration onto the coated surface. The thermoset performance of the coating material had also an important role. This fact, however, does not mean that problems will not occur, primarily in the case of sanded FBs.

Interactions at the interface FB– solid coating and solid coating – solid coating The interactions at the phase boundary FB – primer were evaluated based on the interface energy and adhesion work (Tables 5 and 6). The interface energy values results were of the unsaturated polar component of the surface free energy of the coating. The adhesion primarily resulted from the interaction between non-polar forces associated with the relatively low polarity of the substrate surface. In non-sanded FBs, the cohesion between the layers did not increase significantly until applying the second primer layer and the finishing enamel. In the sanded FBs, however, even this complete coating system did not significantly improve even the adhesion between the second primer layer and the surface enamel.

Table 5. Interface energy in the system FB  solid coating Original FB d p Interface (Phase boundary) S1S2 S1S2 S1S2 [mJ·m2] FB – primer 6.09 0.00 6.09 (FB + 1 primer) – primer 5.01 0.00 5.01 (FB + 2 primer) – finishing enamel 1.78 0.02 1.76 Sanded FB FB – primer 5.28 0.01 5.27 (FB + 1 primer) – primer 5.39 0.00 5.39 (FB + 2 primer) – finishing enamel 5.18 0.01 5.17

Table 6. Adhesion work Wa and parameter S in the system FB  coating Original FB d p Interface (Phase boundary) Wa Wa Wa S [mJ·m2] FB – primer 84.63 59.75 24.88  25.01 (FB + 1 primer) – primer 87.42 60.27 27.15  22.22 (FB + 2 primer) – finishing enamel 101.30 60.59 40.75  12.85 Sanded FB FB – primer 88.64 59.29 29.35  21.00 (FB + 1 primer) – primer 86.18 50.86 26.32  23.46 (FB + 2 primer) – finishing enamel 90.77 59.94 30.83  23.39 a) b)

Figure 2. Schematic representation of solid particles migrating through the coating (a) crater formation (b) movement compelled by surface stress gradient (Witte 1999)

In all measurements, the S parameter values were negative. This means that the dry coating had higher cohesion that the adhesion to the substrate. When the coating system is loaded, the different coating layers are contracting at different rates, and the coating peeling

120 from the substrate is probable (see Fig.1d). Defects, however, may also occur between the first and the second primer layer in non-sanded FBs and in all coating layers in the sanded FBs. The primary cause of orange peel, bordered spots and craters (Figs 1a, b) may result from the coating material contamination with paraffin during the coating application and drying. Paraffin diffusion into the coating material reduced the surface tension of this material (see Tables 2 and 3). In such a case, surface stress gradient originated, causing the coating polymer flow from the sites with a lower to the ones with the higher gradient. The results were uneven surface, orange peel and craters (Fig. 2). Examining the FBs with Scanning Electron Microscope (SEM) revealed that the surface treatment defects at the cover, such as cracking spots and peeling (Fig. 1d), were associated with fibre surface covered with an amorphous substance (Figs. 3 b, c, d) identified potentially as paraffin – based on the surface free energy values. a) b)

c) d)

Figure 3. Fibreboard surface at a spot with impaired coating. a) FB surface before surface treatment, b), c), d) FB surface at disturbed spots exhibiting more paraffin concentration

CONCLUSION Based on the analysis of the results related to thermodynamic characteristics and based on the performed microscopic observations, it can be confirmed that the excessive FB hydrophobization with paraffin has negative impact: lower drying rate of coating materials applied on FBs, worse adhesion of these materials to the substrate equally as the adhesion between the individual layers of the coating system applied, together with increasing the occurrence frequency of the surface treatment defects.

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The application of the first layer of the solvent-based primer on the FB surface caused paraffin to release from the substrate surface and to migrate into the coating. In the sanded FB, the paraffin penetration was also observable in the second layer of the primer. No paraffin, however, was identified on the dried coating system surface after the application of the final, third coating layer consisting of a two-component synthetic enamel. The phase boundary between the FB and the primer demonstrated mostly the interactions between non-polar forces. The correlation found between the adhesion work values and parameter S values confirm that the defects may occur also in the particular coating layers and at interfaces between these layers.

ACKNOWLEDGEMENT: This work was supported by the Slovak Research and Development Agency under the contract No. APVV-16-0177 and by the Scientific Grant Agency of the Ministry of Education SR and the Slovak Academy of Sciences Grant No. 1/0822/17.

REFERENCES 1. CAI, L., FU, Q., NIU, M. et al. 2016: Effect of chlorinated paraffin nanoemulsion on the microstructure and water repellency of ultra-low density fiberboard. BioResources, 11(2): 45794592. 2. GARAI, R. M., SÁNCHEZ, I. C., GARCIA, R. T. et al. 2005: Study on the Effect of Raw Material Composition on Water‐ Repellent Capacity of Paraffin Wax Emulsions on Wood. J. Disper. Sci. Technol., 26(1):918 3. KLOUBEK, J. 1974: Calculation of surface free energy components of ice according to its wettability by water, chlorobenzene and carbon disulphide. J. Colloid Interface Sci., 46: 185–190. 4. KÚDELA, J, JAVOREK, Ľ., MRENICA, L. 2016. Influence of milling and sanding on beech wood surface properties. Part II. Wetting and thermo-dynamical characteristics of wood surface. Ann. WULS-SGGW, For and Wood Technol., No. 95: 154158 5. KÚDELA, J., LIPTÁKOVÁ, E. 2006: Adhesion of coating materials to wood. J. Adhesion Sci. Technol., 20(8): 875895. 6. LIPTÁKOVÁ, E., KÚDELA, J. 1994: Analysis of wood-wetting process. Holzforschung, 48(2): 139–144. 7. LIPTÁKOVÁ, E., KÚDELA, J. 2002: Study of the system wood – coating material. Part 2. Wood – solid coating material. Holzforschung 56(5): 547–557. 8. NEUMANN, A. W., GOOD, R. J., HOPPE, C. J., SEJPAL, M.1974. An equation of state approach to determine surface tensions of low–energy solids from contact angles. Colloid Interface Sci., 49(2): 291–303. 9. ROFFAEL, E., SCHNEIDER, T., DIX, B., BUCHHOLZ, T. 2005: On paraffin sizing of medium density fiberboards (MDF). Part 1: Influence of the chemical composition of paraffin and type of emulsifier on the hydrophobic properties of MDF. Holz als Roh- und Werkstoff, 63(3):192203. 10. STN 67 3052, 1980: Stanovenie zasychania náterových látok. 11. SUCHSLAND, O. 2004: The swelling and Shrinking of wood. A practical technology primer. Madison: Forest Products Society, 189 p. 12. ŠTEFKA, V. 2002: Kompozitné drevné materiály. Časť II. Zvolen: Technická univerzita vo Zvolene, 205 p. 13. TORKAMAN, J. 2008: Reduction of Water Absorption and Swelling of Fiberboard. In.: International Conference on Durability of Building Materials and Components. Istanbul, Turkey 11-14 May 2008, pp. 15.

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14. WITTE, J. 1999: Flourované povrchové aktívní látky pro barvy a nátěry. In.: Nové poznatky v oboru nátěrových hmot a jejích aplikací. Pardubice: Univerzita Pardubice, pp. 198205.

Correspondin author:

Prof. Dr. Jozef Kúdela Department of Wood Science Faculty of Wood Sciences and Technology Technical University in Zvolen T. G. Masaryka 24 960 53 Zvolen Slovak Republic e-mail: [email protected]

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Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 124-130 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Raw material factors affecting the quota of structural wood in sawmill production

MAREK WIERUSZEWSKI, RADOSŁAW MIRSKI, ADRIAN TROCIŃSKI

Department of Wood Based Materials, Faculty of Wood Technology, Poznan University of Life Sciences

Abstract: Construction wood has to meet high requirements for loads capacity. Thanks to the selection and adequate classification of raw materials it is possible to decide how specific wood products can and should be used. The usage of solid wood for structural elements purposes has been precisely classified and specified in standardized requirements. Twelve classes of structural timber, ranging from C14 to C50, have been identified for softwood. Only part of Polish raw wood meets the standards of strength classes required in the building industry, as its strength corresponds to classes C24 and C30. A conclusion from research on the assortment structure of the raw materials in Poland was formed that it is particularly important to sort wood effectively according to its quality and intended use during processing. The material and strength efficiency is the main indicator of rational use of wood. The research resulted in setting the initial classification limits of selected round wood groups according to its strength. Properties determining the possibilities of obtaining a high quality product from the available raw wood material were taken into account in the research. Crucial factor was to select the proper research technology of determining dependencies between the applied research methodology and the defined wood quality, sorting class and strength class. The lower limit of availability of raw material with appropriate technical characteristics is determined during the selection of the research formula.

Keywords: pine raw material, structural timber, strength classes INTRODUCTION Wood needs to meet increasingly high qualitative requirements to be useable as building material. The right classification of the raw material is of utmost importance, as it facilitates planning its applications and specifies the characteristics of wood products. Especially timber must meet strict requirements concerning safety in order to be recognized as proper building material. The assortments which do not meet these requirements can only be used for non-structural purposes – garden structures, packaging materials, fuels, solid wood furniture, etc. European standards number: PN-EN 1995-1-1: 2010 and PN-EN 338: 2003 categorise structural timber into twelve strength quality classes (from C14 to C50). Only part of the Polish raw material meets the standards of strength classes required in the building industry, i.e. C24, C30 and C35. As results from the amendment to the PN-EN 1995-1-1 and PN-D-94021: 2013 standards, other classes have not been fully applied in Poland [Dzbeński et al., 2005]. Results of various sawmills assortment structure studies in Poland, present that its very important to have the effective solution to sort wood according to its quality while it is being processed. The share of individual strength classes resulting from the processing of raw material into timber and sawmill products is a synthetic indicator of round wood [Hruzik, 2003; Hruzik, et al., 2005] rational sawing efficiency. Basic strength classes of softwood, i.e. C24, C30 and C35, were sorted out in the research, allowing for the factors limiting the possibility of obtaining high-quality products from the available materials. Visual assessment being a standard procedure forced mechanical tests to be introduced and verified, what allowed to precisely determine the dependencies between the origin and quality of wood, its sorting class and strength class. In both cases the question arises how to provide the raw material with appropriate technical characteristics.

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Analysis of reference publications and industrial practice based on methods of visual assessment used for sorting domestic wood according to its strength, we now know it is possible to sort 3-6% of sawn timber in the KW class. This result can be defined as a function of the distribution of specific wood structure traits, which affect its mechanical strength [Kozakiewicz and Krzosek 2013]. Correlation between: strength class and sorting class was determined (Tab. 1). The PN-EN 1995-1-1 standard specifies the dependence between: wood species, sorting class and strength class and the PN-EN 338 standard expands specification by dependence between the wood strength class and its sorting class and species defined according to the methodology specified in the PN-D-94021: 2013 standard.

Table 1. The reference from the visual classification PN-D-94021:2013 to strength classes PN-EN 338 Timber Structural wood classes Species thickness C 14 C18 C20 C22 C24 C30 C35 [mm] Pine KG KS KW

Spruce KG KS KW ≥22 Fir KG KS KW

Larch KG KS KW

Currently there are two relation assigning approaches between the strength class and sorting class, depending on the reference document. Structural wood used in constructions that has to meet special requirements concerning the strength. Furthermore structural wood together with designed joints must also meet the strict requirements in seismic areas [Deam et al. 2008]. High resistance to damage is an important aspect of wood properties, which is taken into account by constructors and designers [Loss et al., 2018]. In order to select the proper available structural timber in particular areas, researchers model stresses and calculate the forces acting on the constructions skeleton [Ellingwood et al., 2004]. This research helped to develop the knowledge which is necessary to replace commonly used non-renewable construction materials with wood materials while maintaining the designed strength of structures [Li et al., 2019].

AIM, METHOD AND DESCRIPTION OF STUDY The aim of this study was to determine the quality of structural components made from pine timber. The capacity and qualitative properties of the raw material were compared and referred to its properties and European standards, allowing for the dimensional ranges of timber. In order to classify constructional elements according to their quality intermediate products were acquired from separate parts of fresh mixed forest model long logs. The intermediate products came from the butt zone (symbol A), the middle zone (symbol B) and the apical zone (symbol C) of model long logs of a 86-year-old tree that gave logs with a 3m. The static bending strength of intermediate products and solid wood samples were tested with strength-testing machines SAM and DM 2214. Machine tests, used in assessment of the modulus of elasticity, i.e. the relation between the stress applied to an area and the resulting deformation (relative elongation), are the basis for determining the strength of materials. The efficiency of construction materials increases along with the number of their applications. Machine tests reflect the real strength characteristics of wood what means that the modulus, which is calculated during static

125 bending tests or sonic tests, can be the basis for comparative assessment of technical value of wood. During the research wood was bent at four points to make measurements and calculate the modulus of elasticity. Large-sized elements underwent bending tests on a SAM strength- testing machine. The modulus of elasticity was tested according to the PN-EN 408: 2012 and PN-EN 384: 2016 standard. The size of the deflection arrow was measured with a dial indicator to an accuracy of 0.01 mm. The samples were pre-loaded with a force of 100 N. The bending force was gradually increased by 50 N. The wood moisture was determined after destructive testing on laboratory samples and it was included in the calculation of the strength parameters to a reference humidity of 12%, according to the Bauschinger formula.

SUMMARY OF DATA AND ANALYSIS OF TEST RESULTS Density is a basic physical property which reflects the mechanical properties of wood in raw material characteristics. Table 2 presents the characteristics of the density of the tested intermediate products. The highest average density of timber (542 kg/m3) was noted in the structural elements in sample B. The lowest average density of laths (520 kg/m3) was noted in the structural elements in sample A. It was caused by the content of juvenile wood in the butt zone of model long logs. The density ranges were comparable to the data reported in reference publications [Kokociński, 2004].

Table 2. Mean timber densities in samples A, B and C Cross section of intermediate products (mm) A B C Lath ζ [kg/m3] ζ [kg/m3] ζ [kg/m3] 1(S) 529 554 526 2(S) 520 490 542 3(R) 511 557 520 Mean 520 529 529 S – tangent zone R – core zone

Table 3. The mean width of growth rings in the material Intermediate product cross section (mm) A B C Lath [mm] [mm] [mm] 1(S) 1.95 1.51 1.85 2(S) 2.09 2.51 1.74 3(R) 1.76 1.57 1.82 Mean 1.93 1.90 1.96

The width of growth rings is another physical property related to the quality and usefulness of pinewood. Data in reference publications [Kollman and Core 1968, Krzysik 1978, Kokociński 2004] confirm that narrow annual growth rings indicate higher quality parameters in softwood. According to the standard of visual assessment of structural timber PN-D-94021:2013, the average width of growth rings is a criterion of raw material quality classes. Table 3 shows the average width of annual growth rings measured in subsequent pieces of timber used for the production of intermediate products. The greatest midpoint width of growth rings in timber (1.96 mm) was noted in the structural elements of group C of the apical zone. The smallest average width of growth rings

126 in laths (1.51 mm) was noted in the structural elements of group B. The width of the rings in all the samples ranged from 1.51 mm to 2.51 mm. The mean width of the growth rings ranged from 1.90 to 1.96 mm. Following the adopted classification, the raw material was rated as narrow-ringed and meeting the requirements for structural timber. Humidity being a factor affecting wood strength, its condition was determined within the hygroscopic range, i.e. 0-30%, during the laboratory tests. The average moisture of timber intermediate products in groups A and B was 10%, whereas it was 11% in group C.

STATIC BENDING STRENGTH OF LARGE-SIZED SAMPLES Static bending strength is one of the most common strength tests, which has direct influence on the design of wooden structures. The static bending strength limits for large- sized samples were set in tests according to the standard assumptions [PN-EN 408]. Table 4 array the results. The average strength of large-sized timber elements from the test batch ranged from 29 to 40 N/mm2. The intermediate products from the butt part of the logs were characterised by the lowest average strength ranging from 29 to 39 N/mm2. At the highest spread of values, this timber could be categorised as the C27 strength class. The lowest strength, i.e. 22 N/mm2, was noted in the raw material from the butt zone (A) with the radial cross section (R). The highest strength, i.e. 55 N/mm2, was noted in the wood from the middle (B) and butt zones (A) with the tangential cross section (S)

Table 4. The bending strength of structural elements

2 Rg12 [N/mm ] A B C Zone min mean max min mean max min mean max 1(S) 25 39 48 23 40 55 26 34 45 2(S) 24 35 55 23 36 50 26 39 46 3(R) 22 29 41 26 34 45 25 36 45

The low values of bending strengths of the structural elements were caused by the cumulative scale of defects and changes in the structure in the juvenile wood zone. The central zone between the pressures was the most common place of horizontal stratification in the solid wood under study.

Static bending strength of laboratory samples Following the PN-EN 408:2012 standard, laboratory samples of solid wood were collected from the structural elements for comparative purposes. Table 5 shows the average static bending strength of the samples.

Table 5. The bending strength of model samples 2 Rg12 [N/mm ] A B C Zone min mean max min mean max min mean max 1(S) 53 79 97 49 71 90 59 78 89 2(S) 51 76 90 53 69 85 57 72 82 3(R) 50 71 87 47 63 83 57 67 84

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The laboratory samples of raw material from the tested surface were characterised by the lowest mean strength, i.e. 63-79 N/mm2. The greatest decrease in the strength was observed in the assortments in group B, i.e. 63-71 N/mm2, in contrast to the higher results noted in samples A and B of the structural elements. The greatest midpoint strength, i.e. 71-79 N/mm2 was noted in the samples collected from the butt assortments. The highest bending strength value in the butt zone sample amounted to 97 N/mm2, whereas the lowest was 47 N/mm2. The results were at least twice as high as in those noted in the tests on large-sized elements. This fact confirmed the significant influence of the scale of the tested elements.

MODULUS OF ELASTICITY Table 6 lines up the mean values of Young’s modulus of elasticity, as the main classifying property structural timber into individual structural groups.

Table 6. The modulus of elasticity of large-sized samples with humidity of 12%

2 Value Origin of intermediate product [N/mm ] A B C min 7,845 8,651 8,731 mean 9,646 10,931 9,869 max 11,415 12,415 10,982 Class according to standard PN-EN 338 C20 C22 C20

The highest mean value of the modulus of elasticity (10,931 N/mm2) was noted in the intermediate products from the middle zone (B) of the long logs, whereas the lowest mean modulus of elasticity (9,646 N/mm2) was marked in the intermediate products from the butt zone. It is noteworthy that the mean value of the modulus of elasticity of the raw material from the apical zone met the requirements of strength class C22, according to the PN-EN 338 standard. The lowest value of the modulus of elasticity was noted in the samples from the butt zone – 7,845 N/mm2, whereas the highest value of the modulus of elasticity in the assortments from the middle zone – 12,415 N/mm2. The mean value of the modulus of elasticity of all the intermediate products was 10,148 N/mm2, with a 5% quantile of 7,845 N/mm2. Thus, the whole batch of the tested material can be categorised as strength class C20.

CONCLUSIONS The research led to the following conclusions: 1. The average width of the annual growth rings in domestic softwood subjected to tests and intended for the production of structural elements amounted to about 2 mm. The raw material was narrow-ringed and met the set standard requirements. The density ranged from 520 to 542 kg/m3, which indicated good strength parameters of the pinewood samples. These values were greater than 490 kg/m3 – the value given in the reference publications and required by structural timber standards. 2. In comparison with data given in the PN-EN standard for structural timber, the minimum static bending strength of the intermediate products was low and samples were categorised as class C22 (sample A). According to the strength standards for solid structural timber and the mean values measured in the tests, samples A could be categorised as strength class C27, whereas samples B and C could be categorised as strength class C30. The structural elements with a tangential cross-section were classified

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according to the mean value as C35 for samples A and B. The mean values of the intermediate products with a radial cross-section in zone A amounted to 29 N/mm2, which met the standards of class C27. 3. The midpoint value of the modulus of elasticity of samples A and B was too low to categorise them as structural timber strength class C24. The values of Young’s modulus of elasticity noted in the intermediate products were lower than those measured in the destructive test. The values met the standards of wood strength classes C20 and C22. 4. The values of the static bending strength of the pinewood laboratory samples measured in the experiments met the standards of the highest strength classes and significantly exceeded the values measured in the large-sized elements. Nevertheless, the values measured in these tests were lower than the strength data presented in the reference publications (about 87 N/mm2). 5. The low values of the modulus of elasticity and static bending strength were largely affected by the share of the juvenile wood zone and the origin of the material, which varied from the tangential to radial cross section. In practice, this caused a decrease in the strength parameters of the large-sized samples from the central zone.

REFERENCES 1. DEAM B., BUCHANAN A., FRAGIACOMO M., PALERMO A., 2008: Multi-Story preset ressed timber buildings in New Zealand. Structural Engineering International 2/2008. 2. DZBEŃSKI W., KOZAKIEWICZ K., KRZOSEK S., 2005: Wytrzymałościowe sortowanie tarcicy budowlano-konstrukcyjnej. Warszawa 2005, str. 16-18. 3. ELLINGWOOD R., ROSOWSKY D., LI Y., HEE J., 2004. Fragility Assessment of Light-Frame Wood Construction Subjected to Wind and Earthquake Hazards. Journal of Structural Engineering/Volume 130 Issue 12 - December 2004. 4. HRUZIK G. J., GOTYCZ W., WIERUSZEWSKI M., 2005: Efektywność produkcji przykładowych wyrobów tartacznych na rynek krajowy i europejski. Przemysł Drzewny 5: 18. 5. HRUZIK G.J., 2003: Efektywność przerobu drewna w małych i średnich zakładach tartacznych. Rynek Drzewny, Poznań 2003, nr 3, s. 20-21. 6. KOKOCIŃSKI W., 2004: Drewno. Pomiary właściwości fizycznych i mechanicznych. Wydawnictwo - Drukarnia PRODRUK. 7. KOLLMANN F., CÖTE W.A., 1968: Principles of wood science and wood technology. Solid wood – part I. Berlin-Heidelberg-N. York. 8. KRZYSIK F., 1978: Nauka o drewnie. PWN. Warszawa. 9. KOZAKIEWICZ P., KRZOSEK S., 2013: Inżynieria materiałów drzewnych. Warszawa. Wydawnictwo SGGW. 10. LI J., RISMANCHI B., NGO, T., 2019. Feasibility study to estimate the environmental benefits of utilizing timber to construct high-rise buildings in Australia. BUILDING AND ENVIRONMENT. Volume: 147. 108-120. 11. LOSS C., TANNERT T., TESFAMARIAM S., 2018. State-of-the-art review of displacement-based seismic design of timber buildings. CONSTRUCTION AND BUILDING MATERIALS Volume: 191, 481-497.

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12. PN-EN 338:2003. Drewno konstrukcyjne. Klasy wytrzymałości. 13. PN-EN 384:2016, Drewno konstrukcyjne. Oznaczanie wartości charakterystycznych właściwości mechanicznych i gęstości. 14. PN-EN 408:2012. Konstrukcje drewniane. Drewno konstrukcyjne lite i klejone warstwowo. Oznaczanie niektórych właściwości fizycznych i mechanicznych. 15. PN-EN 1995-1-1: 2010, Eurokod 5 -- Projektowanie konstrukcji drewnianych -- Część 1-1: Postanowienia ogólne -- Reguły ogólne i reguły dotyczące budynków. 16. PN-D-94021:2013 Tarcica iglasta konstrukcyjna sortowana metodami wytrzymałościowymi.

Streszczenie: Czynniki surowcowe wpływające na udział drewna konstrukcyjnego w produkcji tartacznej. Drewno konstrukcyjne posiada wysokie wymagania związane z przenoszeniem określonych obciążeń. Dobór i odpowiednia klasyfikacja surowca pozwala na określenie kierunków oraz sposobów zastosowania wyrobów drzewnych. Zastosowanie drewna litego na elementy konstrukcyjne zostało precyzyjnie zaklasyfikowane i ujęte w wymaganiach spełniających procedury normowe, wydzielając dla drewna iglastego dwanaście klas tarcicy konstrukcyjnej od C14 do C50. Tylko część rodzimego surowca odpowiada zdefiniowanym klasom wytrzymałości znajdującym zastosowanie w budownictwie charakteryzując się zgodnością wytrzymałości dla klas C24, C30. Badania struktury asortymentowe surowca w Polsce wskazują, iż fundamentalne znaczenie posiada efektywne sortowanie jakościowo- przeznaczeniowe drewna w trakcie jego przerobu. Głównym wskaźnikiem racjonalnego wykorzystania drewna jest wydajność materiałowo-wytrzymałościowa z danego surowca. Badania pozwoliły ustalić wstępne granice klasyfikacji wytrzymałościowej dla wybranych grup drewna. Uwzględniono właściwości, które określają możliwości pozyskania wysoko jakościowego produktu z dostępnego materiału. Dużą wagę niesie za sobą dobór technologii badań, która określa zależności między metoda badań i jakością drewna, klasą sortowniczą, jak i klasą wytrzymałości. W doborze formuły badawczej określa się graniczny poziom dostępności surowca o odpowiednich cechach technicznych.

Słowa kluczowe: surowiec sosnowy, drewno konstrukcyjne, klasy wytrzymałości

Corresponding author:

Wieruszewski Marek Department of Wood-based Materials, Faculty of Wood Technology, Poznan University of Life Sciences, Poznan, Poland [email protected]

ORCID ID: Wieruszewski Marek

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Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 131-138 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

The chemical composition of poplar wood in relation to the species and the age of trees

DONATA KRUTUL, ANDRZEJ ANTCZAK, ANDRZEJ RADOMSKI, MICHAŁ DROŻDŻEK, TERESA KŁOSIŃSKA, JANUSZ ZAWADZKI Department of Wood Science and Wood Protection, Institiute of Wood Sciences and Furniture, Warsaw University of Life Sciences – SGGW

Abstract: The chemical composition of poplar wood in relation to the species and age of trees. The contents of the following substances: mineral substances, extractives, cellulose, lignin, holocellulose, in wood from fast- growing poplar species (Populus deltoides x maximowiczii and Populus trichocarpa Torr and A.Gray) aged 2.5, 3, 5 and 7 years were compared to the contents of the abovementioned substances in Populus nigra L. and Populus alba L. wood, aged about 30. According to other publications, the cellulose and lignin contents increase in line with the tree's age. On the other hand, the comparison of cellulose content in studied poplar wood showed that its content did not depend from the species of tree, age and growth environment. Whereas, the content of extractives in poplar wood was dependent from the species of tree and growth environment. The lignin content in Populus deltoides x maximowiczii and Populus trichocarpa wood did not depend from its age and was similar to the lignin content in 30-year-old P. nigra wood. 30-year-old wood of P. nigra and P. alba contained less holocellulose compared to its contents in P. deltoides x maximowiczii and P. trichocarpa wood, regardless of its age.

Keywords: poplar wood, mineral substances, extractives, cellulose, lignin, holocellulose

INTRODUCTION The percentage of particular components in the structure of wood tissue depends on factors like: species of tree, environmental conditions of its growth, their determination method and other factors. According to species, also age of tree, among others, has an impact on chemical composition of wood. This impact is especially visible in coniferous species, while it varies among the deciduous ones. Poplar (Populus) belongs to the Salicaceae family. Approximately 30 of the fastest- growing (in our climate) tree species, form the Populus genus. The poplar wood is light, very soft, easily cleavable, glueable, easily accepts dyes and impregnants; in humid environment it is very prone to fungi-induced decomposition. The poplar wood is highly appreciated in cellulose and paper industry and is often used for food packaging in form of wood wool. The particularly often used species are these fast-growing, such as Populus deltoides x maximowiczii or Populus trichocarpa Torr and A. Gray hybrides. These poplars have been investigated as a mean to obtain biomass - renewable energy sources, including raw material for bioethanol production (Antczak et al. 2016, Antczak et al. 2018, Antczak et al. 2019, Sannigrahi et al. 2010). Throughout the abovementioned research, the lignocellulose biomass has been obtained from the 1, 2, 3, 5 and 7-year-old trees. According to Prosiński and Surmiński (Prosiński, 1984), the contents of mineral substances, extractives and pentosans are higher in 1-year-old Salix acutifolia shoots by 30%, 31% and by 13% as compared to 3-year-old willow wood, while the contents of cellulose and lignin are lower by 10% and 15% respectively. On the other hand, the wood of 2-year-old sharp-leaf willow shoots contains 35% less mineral substances as compared to 1-year-old shoots and 8% as compared to 3-year-old shoots. Furthermore, the wood of 2-year-old shoots contains 30% less extractives as compared to 1-year-old shoots and 3% less as compared to 3- year-old shoots. A tendency is evident, that the contents of cellulose and lignin in wood

131 increase gradually in parallel with the S. acutifolia shoots' age, while pentosans content decreases (Prosiński 1984). According to data provided by Waliszewska and Wiśniewska (2005), cellulose content in shrub willows depends on species. The wood of 1-year-old swedish willow (variety Orn. Valne) and Salix americana x viminalis are characterized by a higher cellulose content determined with the use of Seifert method by about 15% as compared to its content in basket willow wood and by 10% as compared to S. americana wood. Whereas, S. viminalis wood is characterised by 35% higher lignin content as compared to its content in S. americana x viminalis wood and by 13% as compared to S. americana and S. viminalis x acutifolia wood. The wood of 1-year-old S. viminalis shoots presents about 25% lower cellulose content as compared to 27-year-old Salix caprea L. in bottom part and by 17% lower at DBH (Diameter of Breast Height) (Waliszewska and Wiśniewska 2005, Waliszewska and Prądzyński 2005). The wood of 1-year-old S. americana, S. viminalis x acutifolia shoots has a comparable lignin content as compared to the wood in bottom part and at the DBH of 27-year-old S. caprea. On the other hand, the wood of 1-year-old S. americana x viminalis has 20% lower lignin content, and the wood of S. viminalis x caprea has 15% lower lignin content as compared to the 27-year-old S. caprea. According to the data provided, the contents of particular components depends on the species and age of a tree. It is therefore purposeful to compare the chemical composition of fast-growing P. deltoides x maximowiczii and P. trichocarpa varieties with the wood of about 30-year-old black poplar and white poplar wood.

MATERIAL AND METHODS Chemical composition of 2.5, 3, 5 and 7-year-old Populus deltoides x maximowiczii and Populus trichocarpa wood was compared to that of 30-year-old Populus nigra and Populus alba wood. The 2.5, 3, 5 and 7-year-old poplars were harvested from the experimental field of the Department of Genetics, Breeding and Biotechnology of Plants, Faculty of Horticulture and Landscape Architecture in Wolica. Whereas black and white poplar from the areas of Wielkopolskie and Pomorskie voivodships. Extractives content in the P. deltoides x maximowiczii and P. trichocarpa was determined with the use of chloroform-ethanol mixture (93:7 w/w) and in the 30-year-old Populus alba and Populus nigra wood with the use of benzene-ethanol mixture (1:1 w/w). Cellulose content was determined by Kürschner-Hoffer method according to Krutul (2002). Lignin content in 2.5, 3 and 5-year-old Populus deltoides x maximowiczii and Populus trichocarpa wood was determined spectrophotometrically with the use of acetyl bromide (Antczak et al. 2013). Whereas lignin content in 7-year-old Populus deltoides x maximowiczii and Populus trichocarpa wood and in the 30-year-old Populus alba and Populus nigra wood was determined according to PN-92/P-50092 standard. Holocellulose content was analyzed according to PN-92/P-50092 standard and Krutul (2002). All of the chemical composition analysis were done in triplicate and single standard deviations were calculated.

RESULTS AND DISCUSSION Particulars concerning the wood components content of P. deltoides x maximowiczii and P. trichocarpa in 2.5, 3, 5 and 7-year-old wood and about 30-year-old P. nigra and P. alba wood are shown in Fig. 1-5. Accordant with data shown in Fig. 1, mineral substances content in 7-year-old wood of P. deltoides x maximowiczii was nearly 40% lower than in 2.5, 3, 5-year-old wood, where the mineral substances content was the same. Equally, mineral substances contents in the 7- year-old P. deltoides x maximowiczii wood was about 30% lower as compared to 30-year-old P. nigra wood, but 30% lower as compared to 30-year-old P. alba wood. Content of mineral

132 substances in 7-year-old wood of P. trichocarpa was about 40% lower than in 2.5 and 5-year- old wood and over two times higher as compared to 3-year-old wood, while mineral substances content in 7-year-old wood of P. trichocarpa was similar to the contents of mineral substances in 30-year-old P. alba wood and two times lower than in P. nigra wood.

0.75 0.77 0.77 0.75 0.59 0.64 0.56

0.44

0.33 0.30 Mineral substances [%] substances Mineral

0 a b c d e f g h i j

Figure 1. Mineral substances content in poplar wood: a – Populus deltoides x maximowiczii, 2.5-year-old; b – P. deltoides x maximowiczii, 3-year-old; c – P. deltoides x maximowiczii, 5-year-old; d – P. deltoides x maximowiczii, 7-year-old; e – Populus trichocarpa Torr and A. Gray, 2.5-year-old; f – P. trichocarpa, 3-year- old; g – P. trichocarpa, 5-year-old; h – P. trichocarpa, 7-year-old; i – Populus nigra L., about 30-year-old; j – Populus alba L., about 30-year-old.

The P. trichocarpa 2.5, 5, 7-year-old wood had lower mineral substances content in comparison to P. deltoides x maximowiczii wood, while 3-year-old P. trichocarpa wood contained similar percentage of mineral substances comparing to P. deltoides x maximowiczii 2.5, 3, 5-year-old wood, as well as to 30-year-old P. nigra wood and amounts to 0.75% according to Bowersox et al. (1979) data, the content of mineral substnances in poplar hybrids' wood was 0.8%, which meant that 7-year-old P. deltoides x maximowiczii and P. trichocarpa wood contained two times less mineral substances. At the same time, 2.5, 3 and 5-year-old P. deltoides x maximowiczii wood and 3-year-old P. trichocarpa contained similar percentage of the abovementioned substances present in the wood of poplar hybrids grown in the center of Pennsylvania. Summarizing, it should be stated that wood of 7-year-old P. deltoides x maximowiczii and P. trichocarpa contained less mineral substances as compared to their contents in 2.5, 3 and 5-year-old wood and similar percentage to wood in 30-year-old P. alba (Fig. 1). According to the data shown in Fig. 2, the content of extractives, where the chloroform-ethanol mixture (93:7 w/w) was used as a solvent, reached the levels between of 2.5% to 2.1% in P. deltoides x maximowiczii wood and 1.7% to 1.5% in P. trichocarpa wood. For the approximately 30-year-old white poplar wood the content of extractives, where benzene-ethanol mixture (1:1 w/w) was used as a solvent, reached the level of 5.7% and 1.8% in black poplar wood. According to data provided by Drożdżek (2011), the content of extractives in the 30-year-old white poplar, where chloroform-ethanol mixture (93:7 w/w) was used as a solvent, reached the level of 3.3%. It can be stated, that 30-year-old P. alba wood contained from 2 to 3 times more extractives as compared to their content in P. deltoides x maximowiczii, P. trichocarpa and P. nigra wood. According to Sannigrahi et al. (2010), it can be stated, that the extractives content in Populus tremuloides determined with

133 the use of benzene-ethanol mixture, was 2.4%, 1.4% in P. deltoides and 2.7% in P. trichocarpa wood.

7 5.7 6

3 2.5 2.1 2.2 2.1 1.7 1.7 1.7 1.8 Extractives[%] 2 1.5

0 a b c d e f g h i j

Figure 2. Extractives content in poplar wood: a – Populus deltoides x maximowiczii, 2.5-year-old; b – P. deltoides x maximowiczii, 3-year-old; c – P. deltoides x maximowiczii, 5-year-old; d – P. deltoides x maximowiczii, 7-year-old; e – Populus trichocarpa Torr and A. Gray, 2.5-year-old; f – P. trichocarpa, 3-year- old; g – P. trichocarpa, 5-year-old; h – P. trichocarpa, 7-year-old; i – Populus nigra L., about 30-year-old; j – Populus alba L., about 30-year-old.

According to data shown in Fig. 2, P. deltoides x maximowiczii wood contained from 33% to 44% more extractives as compared to P. deltoides wood grown in North America. On the other hand, the studied P. trichocarpa wood contained from 37% to 44% less extractives than in P. trichocarpa wood from North America (Sannigrahi et al. 2010). Depending on recorded data a conclusion was drawn that the extractives contents in the wood of studied poplar hybrids depends on the environment in which they grow, as well as on their species variety. Furthermore as cellulose is “the basic” wood component, which determines its physical and mechanical properties a second conclusion may be formed, that the cellulose content in the studied poplar hybrids' wood was changing only within the range from 50.2% to 53.0% and was similar to the cellulose content in about 30-year-old P. nigra and P. alba wood (Fig. 3). The highest differences (by up to about 3 percentage points) of cellulose content can be found in 5-year-old P. deltoides x maximowiczii and P. trichocarpa wood as compared to its content in 7-year-old P. deltoides x maximowiczii and P. trichocarpa wood, whereas other differences are within the limits of determination error. On the contrary, as a tree gets older, according to Prosiński (1984), the content of cellulose and lignin increases. For example, cellulose content in 9-year-old wood of alders was 39.6% and in 7-year-old – 45.5%. In the wood of 70-year-old alder, there was 13% more cellulose than in 9-year-old alder. Also, in the wood of 1-year-old Salix acutifolia, the cellulose content determined by Kürschner-Hoffer method amounted to 47.24% and in the wood of 3-year-old shoots to 54.76%. In the studied P. deltoides x maximowiczii and P. trichocarpa as well as in about 30- year-old P. alba and P. nigra no interdependence between cellulose contents and tree's age were found.

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54 53.0 52.6 52.5 52.6 52.0 52.0 53 51.7 51.5

51 50.4

50.2 Cellulose [%] Cellulose 50

48 a b c d e f g h i j

Figure 3. Cellulose content in poplar wood: a – Populus deltoides x maximowiczii, 2.5-year-old; b – P. deltoides x maximowiczii, 3-year-old; c – P. deltoides x maximowiczii, 5-year-old; d – P. deltoides x maximowiczii, 7- year-old; e – Populus trichocarpa Torr and A. Gray, 2.5-year-old; f – P. trichocarpa, 3-year-old; g – P. trichocarpa, 5-year-old; h – P. trichocarpa, 7-year-old; i – Populus nigra L., about 30-year-old; j – Populus alba L., about 30-year-old.

According to the data presented in Fig. 4, P. deltoides x maximowiczii and P. trichocarpa wood contained similar amounts of lignin, irrespectively from its age: from 19.1% to 20.7% (Fig. 4). The lignin content in about 30-year-old black poplar was 20.8% and was similar to its content in 5-year-old P. deltoides x maximowiczii wood (20.7%). The highest amount of lignin was observed in about 30-year-old white poplar (21.3%).

22 21.3 20.7 20.2 20.8 21 20.0 20.1 19.7 19.9 20.0 20 19.1

18 Lignin [%] Lignin 17

15 a b c d e f g h i j

Figure 4. Lignin content in poplar wood: a – Populus deltoides x maximowiczii, 2.5-year-old; b – P. deltoides x maximowiczii, 3-year-old; c – P. deltoides x maximowiczii, 5-year-old; d – P. deltoides x maximowiczii, 7-year- old; e – Populus trichocarpa Torr and A. Gray, 2.5-year-old; f – P. trichocarpa, 3-year-old; g – P. trichocarpa, 5-year-old; h – P. trichocarpa, 7-year-old; i – Populus nigra L., about 30-year-old; j – Populus alba L., about 30-year-old.

According to data obtained by Komorow (Prosiński 1984) 43-year-old poplar wood contained 20% and 9% more lignin respectively, as compared to its content in 17-year-old and 22-year-old poplar wood. 135

The P. trichocarpa wood contained slightly higher percentage of holocellulose (from 2 to 4 percentage points) as compared to its content in P. deltoides x maximowiczii wood and higher, from about 9 to 11 percentage points as compared to the P. alba and P. nigra respectively (Fig. 5).

85.4 85.7 85.6 85.4 85 83.5 83.1 82.1 82.0

80 75.8 Holocellulose[%] 74.7 75

70 a b c d e f g h i j

Figure 5. Holocellulose content in poplar wood: a – Populus deltoides x maximowiczii, 2.5-year-old; b – P. deltoides x maximowiczii, 3-year-old; c – P. deltoides x maximowiczii, 5-year-old; d – P. deltoides x maximowiczii, 7-year-old; e – Populus trichocarpa Torr and A. Gray, 2.5-year-old; f – P. trichocarpa, 3-year- old; g – P. trichocarpa, 5-year-old; h – P. trichocarpa, 7-year-old; i – Populus nigra L., about 30-year-old; j – Populus alba L., about 30-year-old.

An assumption can be formed that 30-year-old wood of the P. alba and P. nigra contained less holocellulose as compared to P. deltoides x maximowiczii and P. trichocarpa, regardless of their age.

CONCLUSIONS Analysis of chemical wood composition of Populus deltoides x masimowiczii and Populus trichocarpa 2.5, 3, 5 and 7-year-old and 30-year-old wood from Populus nigra and Populus alba showed that:

- the wood of 7-year-old P. deltoides x maximowiczii and P. trichocarpa contained less mineral substances as compared to their contents in 2.5, 3 and 5-year-old wood and similar percentage to wood in 30-year-old P. alba,

- the extractives content in poplar wood depended from its variety and growth environment,

- the cellulose content in poplar wood did not depend from its age, variety and growth environment,

- the lignin content in Populus deltoides x maximowiczii and Populus trichocarpa wood did not depend from its age and was similar to the lignin content in 30-year-old P. nigra wood,

- 30-year-old P. nigra and P. alba wood had a lower holocellulose content as compared to its contents in wood of P. deltoides x maximowiczii and P. trichocarpa, regardless of their age.

136

ACKNOWLEDGEMENTS: This work was financed by project from the National Centre for Research and Development, which was “Intelligent systems for breeding and cultivation of wheat, maize, and poplar for optimized biomass production, biofuels, and modified wood” (BIOSTRATEG2/298241/10/NCBR/2016).

REFERENCES

1. ANTCZAK A., MARCHWICKA M., SZADKOWSKI J., DROŻDŻEK M., GAWRON J., RADOMSKI A., ZAWADZKI J., 2018: Sugars yield obtained after acid and enzymatic hydrolysis of fast-growing poplar wood species, BioResources 13(4); 8629-8645 2. ANTCZAK A., MICHAŁUSZKO A., KŁOSIŃSKA T., DROŻDŻEK M., 2013: Determination of the structural substances content in the field maple wood (Acer campestre L.) – comparison of the classical methods with instrumental, Annals of Warsaw University of Life Sciences, Forestry and Wood Technology, 82, 11-17 3. ANTCZAK A., ŚWIERKOSZ R., SZENIAWSKI M., MARCHWICKA M., AKUS- SZYLBERG F., PRZYBYSZ P., ZAWADZKI J., 2019: The comparison of acid and enzymatic hydrolysis of pulp obtained from poplar wood (Populus sp.) by the Kraft method, Drewno 62(203); 1-14 4. ANTCZAK A., ZIĘTEK K., MARCHWICKA M., TYLKO B., GAWKOWSKI A., GAWRON J., DROŻDŻEK M., ZAWADZKI J., 2016: The sugars isolated from fast-growing poplar biomass (Populus sp.) as a raw material for production of bioethanol, Przemysł Chemiczny 95 (9); 1770-1773 5. BOWERSOX T. W., BLANKENHORN P. R., MURPHEY W. K., 1979: Heat of combustion, ash content, nutrient content and chemical content of populus hybrids, Wood Science 11; 257-262 6. DROŻDŻEK M., 2011: Study of cellulose separated by selected laboratory methods from pinewood (Pinus sylvestris L.) and poplar wood (Populus sp.), doctoral thesis, Poland, Warsaw 7. KRUTUL D., 2002: Ćwiczenia z chemii drewna oraz wybranych zagadnień z chemii organicznej, SGGW, Warszawa 8. PN-92/P-50092 Surowce dla przemysłu papierniczego. Drewno. Analiza chemiczna 9. PROSIŃSKI S., 1984: Chemia drewna (Wood chemistry), PWRiL, Warszawa 10. SANNIGRAHI P., RAGAUSKAS A. J., TUSKAN G. A. 2010: Poplar as a feedstock for biofuels: a review of compositional characteristics, Biofuels, Bioproducts & Biorefining 4; 209-226 11. WALISZEWSKA B, PRĄDZYŃSKI W., 2005: Chemical composition and heavy metals content in willow trees (Salix caprea L.), Annals of Warsaw University – SGGW, Forestry and Wood Technology 57; 279-282 12. WALISZEWSKA B., WIŚNIEWSKA J., 2005: Chemical composition and heat of combustion of selected bush willows, Annals of Warsaw University – SGGW, Forestry and Wood Technology 57; 283-286

Streszczenie: Skład chemiczny drewna topoli w zależności od gatunku i wieku drzewa. Porównano zawartość substancji mineralnych, ekstrakcyjnych, celulozy, ligniny, holocelulozy w 2,5-letnim, 3-letnim, 5-letnim, 7-letnim drewnie szybko rosnących gatunków topoli (Populus deltoides x maximowiczii i Populus trichocarpa Torr and A.Gray) z zawartością tych substancji w drewnie około 30-letnim topoli czarnej (Populus nigra L.) i topoli białej (Populus alba L.). Z danych literaturowych wynika, że wraz ze wzrostem wieku drzewa zwiększa się w nim zawartość celulozy i ligniny. Natomiast z porównania danych zawartości celulozy w drewnie topoli otrzymanych w tej pracy, okazało się, że zawartość celulozy nie zależała od gatunku, wieku i środowiska wzrostu drzewa. Z kolei zawartość substancji ekstrakcyjnych w drewnie

137 topoli była zależna od gatunku i środowiska wzrostu drzewa. Zawartość ligniny w drewnie Populus deltoides x maximowiczii i Populus trichocarpa nie zależała od wieku drzewa i była podobna do zawartości ligniny w drewnie 30-letniej Populus nigra L. Drewno około 30-letnie topoli czarnej i białej charakteryzowało się mniejszą zawartością holocelulozy w odniesieniu do jej zawartości w drewnie P. deltoides x maximowiczii i P. trichocarpa, niezależnie od ich wieku.

Corresponding authors:

Teresa Kłosińska Department of Wood Science and Wood Protection, Institiute of Wood Sciences and Furniture Warsaw University of Life Sciences (SGGW) 159 Nowoursynowska St., 02-776 Warsaw, Poland e-mail: [email protected]

Andrzej Antczak Department of Wood Science and Wood Protection, Institiute of Wood Sciences and Furniture Warsaw University of Life Sciences (SGGW) 159 Nowoursynowska St., 02-776 Warsaw, Poland e-mail: [email protected]

ORCID ID: Andrzej Antczak 0000-0003-1876-3519 Teresa Kłosińska 0000-0001-6538-2634 Michał Drożdżek 0000-0001-7979-6897 Janusz Zawadzki 0000-0003-1431-4388

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Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 139-148 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019)

Testing the tightness of a square joint between oak wood elements

EWA DOBROWOLSKA, DANIEL KUPIEC, ZBIGNIEW KARWAT Department of Wood Science and Wood Preservation, Warsaw University of Life Sciences – SGGW

Abstract: Testing the tightness of a square joint between oak wood elements. The study was carried out to determine the tightness of square joints between elements made of oak wood. To determine the degree of tightness of these joints, a device measuring the swelling pressure of oak wood under the influence of water humidification was designed. Checking the tightness of joints was carried out for surfaces obtained by machining through: grinding, milling, machine planing and manual planing. Contact angles at the phase boundary wood-water and their roughness achieved as a result of machining were also determined. During the wood swelling pressure test, the values of the preload of square joints were changed. The analysis of the results showed that the tightness of the square joint is influenced mainly by the roughness of the surface obtained as a result of machining and the size of the force of the initial load exerted on the moistened surfaces.

Keywords: swelling pressure, roughness, tightness of joints, oak wood

INTRODUCTION Square joints between elements made of oak wood are found mainly in cooper products [Papierowski 1952, Świtkowski 1957, Zenkteler 1971, Dobrowolska, Niemz 2016], used for storage and maturing of noble wine, alcohols, whiskey, port, beer and others. Due to the specific characteristics of cooper's products, the manufacturing process consists of many operations, including obtaining from logs and bolts elements with appropriate cross- sections, drying process [Bernatowicz, Guzenda and others 1996; Bernatowicz 1996; Glijer 2007 and many others] and surface forming. According to the principles of traditional cooper’s craft, the surfaces of the elements were formed with hand planers and spokes haves. Nowadays, for this purpose, various methods of mechanical processing are used, allowing to obtain a surface that ensures the tightness of square joints [Prządka, Szczuka 1997]. It is possible thanks to proper surface roughness, which is influenced not only by the machining process, but also by the anisotropy and heterogeneity of the wood structure. The tightness of square joints is also associated with the dimensional stability of the wood during soaking. As a result of moisture exposure, the linear and volumetric dimensions of wood [Niemz , Sonderegger 2017] change. During moisture absorption, the adsorption forces are greater than the forces of intermolecular cohesion and cause swelling of the wood. The restriction of the freedom of swelling leads to the formation of swelling pressure, which achieves its highest value while suppressed in three anatomical directions. Stopping the swelling in one or two directions reduces swelling pressure resulting from the deformation of the material in the other free directions. Unidirectional swelling damping occurs in elements connected by square joints [Prekitny 1951, Raczkowski 1960, Stefaniak 1962, Krzysik 1975, Krauss 1988, 2004]. By applying a sufficiently high preload to the joints, the size of the swelling, and thus the swelling pressure, is reduced [Perkitny 1951, Glijer 2007, Świderski 1966, Rybarczyk, Ganowicz 1974]. The analysis of the literature shows that there is a lack of detailed information on surface properties, such as wettability and roughness, associated with the treatment of oak wood elements, ensuring high tightness of square joints.

PURPOSE OF THE STUDY The purpose of the study was made to characterize the properties of the oak wood surface which ensures the making of a tight square joint. Above all, attention was paid to the

139 influence of various types of processing and the influence of the initial force pressing the surface on the tightness of the obtained joints. An attempt was to determine the tightness of a square joint between elements made of oak wood with surfaces milled, ground and planed with a manual and machine planer. The scope of work included designing and construction of a device for testing the tightness of joints by measuring the swelling pressure while moistening wood with water. The significance of the initial load and the influence of roughness and wettability of the oak wood surface on the tightness of square joints were determined during the swelling pressure measurement.

METHODOLOGY Test material The samples were made of 1 class (PN-72 D-96002) oak hardwood, without defects, without knots or twisted fibres. The width of the samples was along the radial direction [Fig. 1].

A B

Figure 1: Radially cut oak samples 30 mm×40 mm (A) and 70 mm and 140 mm in length (B)

Figure 2: Arrangement of samples for testing the tightness of a square joint taking into account the direction of annual increments

The thickness of the samples was 30 mm and the width was 40 mm, The length of the sample corresponded to the length of the joint being tested and was 70 mm or 140 mm, forming, together with the thickness, a contact area between the samples [Fig. 1]. The device for measuring the swelling force during the single-sided moistening process is designed for a maximum load of 5.88 kN, with a sample length of not more than 230 mm and a contact area of not more than 700 mm2 [Krzysik 1975, Perkitny 1951]. The length of the samples equal to 70 mm was taken for the first variant of the test and 140 mm for the second variant. The moisture content of the test material was 6%. The average grain size was 2.01 mm with a standard deviation of 0.35 mm, i.e. 17.5% of the average value (the determination was made in accordance with PN-55/D-04110). The density test was performed on 20 samples of average density of 701 kg/m3 (at the coefficient of variation for density measurement it is 3.0%), the shrinkage of the oak wood in the radial direction was 4.1% (PN-77/D-04101; PN-82/D-04111). The arrangement of the samples as shown in Figure 2 when square jointed eliminates any additional forces that may affect the level of the swelling pressure.

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Surface treatment and determination of roughness and wettability The surface of the samples was formed with:  Shank cutter with a diameter of 50 mm with four blades at the 14.000 rpm,  Manual plane, thickness cut of 0.3 mm (the blade protrusion) with feed rate about 0.5 m/s,  Sandpaper of 400 grit,  Thicknesser with cutter head with a diameter of 100 mm and with four blades at the 4.500 rpm. The test of roughness of the obtained surfaces was performed on a portable device for measuring roughness “Mitutoyo”. The study distinguished roughness values such as Rz and Ra according to PN-84/D01005 standard. The measurement section was 12 mm and was carried out in places free from cut vessels and medullary ray. The test was carried out along and across the fibres. The contact angle was also measured in areas free from cut anatomical elements of wood in the form of vessels and wood rays. Lower roughness values mean lower occurrence of micro irregularities on the surface of the sample. The contact angle was examined by goniometric method with a universal goniometer device 300 from Phoenix Surface Electro Optics program-controlled Image XP 5.6. Distilled water was the liquid used in the study. Drops of water with a volume of 1 μl were dropped on the examined area and then a properly set camera recorded the image showing the change in its profile. Photographs of the drops were taken in the first second and after 30 seconds. The test for each surface was repeated 10 times. The angle between the surface of the sample and the tangent to the surface of the droplet was measured using appropriate software for photographic analysis.

Measurement of swelling pressure A device with adequate stiffness and dimensional stability was designed to test the swelling pressure.

Figure 3. A diagram of a device for measuring Figure 4. A measuring instrument with samples swelling pressure and testing the tightness of a contact mounted in it, connected with a square joint, and a connection:1-samples, 2-beam strain gauges vessel with water insulated with silicone

A diagram of the test facility is shown in Figure 3. It consisted of the following components:  a section of rectangular cross-section 40 mm × 40 mm × 4 mm × 4 mm,  two strain gauge beam sensors with a force range from 0 to 2.94 kN,  stainless steel plates of various thicknesses,  M8 bolts made of hardened steel,  a microprocessor for communication with a computer and calibration of sensors,  a liquid storage vessel. The initial load setting is achieved by installing bolts and washers of different thicknesses. The values of the initial load and the tracking of swelling pressure changes were

141 controlled by two strain gauges, each up to 2.94 kN, giving a maximum force of up to 5.88 kN. The observation of the change in the swelling force made it possible to determine the maximum moisture content and swelling of the test material and the tightness of the joint. Before each test, the device was calibrated and then two samples were placed in it, which were connected with a square joint with properly prepared surfaces, while maintaining the course of core radii in the same plane (Fig. 4).

Table 1. Variations in preload of samples depending on machining type Sample Version I Version II No. Sample type Initial load [MPa] Sample type Initial load [MPa] 1 Milling 0.09 Milling 0.06 2 Milling 0.18 Grinding 400 0.06 3 Milling 0.30 Thicknesser 0.06 4 Milling 0.36 Manual plane 0.06 5 Milling 0.52 - -

Washers of different thickness were inserted between the strain gauge and the samples, depending on the expected preload force (Tab. 1). Next, a vessel was placed on the surface of the samples, the edges of which were insulated with silicone and filled with water (Fig. 4). The results were recorded for over two days with a 5-second interval. The water level in the vessel was supplemented and maintained at a constant level as the samples permeated and evaporated freely. The test lasted until the moment when the swelling force stabilized. The tightness was assessed by observing the loss of liquid from the vessel irrigating the weld and by observing the seepage of liquid on the weld line in the cross-section. No loss of liquid in the vessel and drying of wood meant tightness of the joint.

TEST RESULTS Results of conducted analyses include: roughness and contact angle of the surface depending on the machining method and the influence of the initial contact load on the swelling pressure. The roughness and contact angle of the surface were tested on 140 mm long samples. The surfaces of the samples were prepared by machining: milling, grinding, manual planing by hand or by machine on a thicknesser. Photographs of the surfaces are shown in Fig. 5÷8.

Table 2. Surface roughness measured along the fibres after different types of machining Surface preparation Measured values Milling Thicknesser Grinding Planer Ra 1.316 3.806 1.326 2.036 Average value Rz 8.328 20.536 10.312 12.948 s a 0.298 0.577 0.255 0.609 Standard deviation R sRz 1.772 4.473 2.247 3.607 Coefficient of VRa [%] 22.7 15.2 19.3 29.9 variation VRz [%] 21.3 21.8 21.8 27.9

The highest values for roughness, Ra, Rz, measured in the direction along the fibres (Tab. 2) and across the fibres (Tab. 3) are shown by the surface formed by mechanical planing on the thicknesser. In this case, the average value of Ra/Rz, from four measurements, for the direction along the fibres was 3.806/20.536 and across the fibres 2.869/19.052. For milling and grinding, the Ra/Rz values in the direction along the fibres were 1.316/8.328 and 1.326/10.312 respectively and 2.236/14.504 and 1.786/14.046 across the fibres, respectively. The surface roughness after manual planing exceeded the roughness after milling and grinding, equalling 2.036/12.948 along the fibres and 2.236/39.901 across the fibres. The highest surface smoothness was obtained after grinding with sand paper and milling.

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Table 3. Surface roughness measured across the fibres after different types of machining Surface preparation Measured values Milling Thicknesser Grinding Planer Ra 2.236 2.869 1.786 3.427 Average value Rz 14.,504 19.052 14.046 39.901 Ra 0.414 0.566 0.449 0.786 Standard deviation Rz 2.773 3.912 2.547 3.646 Coefficient of Ra [%] 18,5 19.7 25.2 22.9 variation Rz [%] 19.1 20.5 18.1 9.1

Figure 5. Contact surface after milling, with visible Figure 6. Contact surface after processing with waves abrasive paper grit 400, with visibly chipped grain

Figure 7. Contact surface after manual planing, with Figure 8. Contact surface formed using a thicknesser, visible small waves characteristic deep wavy surface visible

Figure 9. Contact angle for the surfaces of samples for individual processing methods at the beginning of the test (1 s) and after 30 s

A square joint that requires a high degree of smoothness to ensure the exact adhesion of the pressed surfaces eliminates the formation of a gap through which water can percolate. The highest surface smoothness was achieved with milling. The results of the contact angle measurement are shown in Fig. 9. The highest contact angle was found for the milled surface and the lowest for the ground surface. Absorbent

143 properties of water droplets deposited on the milled wood surface are the lowest in comparison to other methods of its processing. The change of contact angle for the milled surface in 30 seconds equalled 2.8°, and for the sanded paper – 11°. The results of the investigations show that the surfaces in contact with the ground surface will soak faster than those obtained by other methods of machining.

Figure 10. Characteristic areas of change in oak square joint swelling pressure at 0.1 MPa initial load

Figure 11. Swelling pressure depending on the size of the preload of the square joint of two oak wood surfaces

The study of the swelling pressure was preceded by an evaluation of the influence of the initial load exerted on the connection of two milled surfaces (Fig. 10). The change of swelling pressure in time, at the initial load of 0.1 MPa, shows a characteristic course which can be divided into three areas. The first one (I) covers the contact pressure of the samples, which are lightly compressed under initial loading. As the compression ratio increases, the preload force decreases slightly and stabilizes. The second area (II) is related to the direct moistening of the contact surface of the samples and the increase of the swelling pressure, initially very intensive (IIa) due to the rapid penetration of moisture into the wood structure, and then slowing down over time (II b). The analysis of changes in the magnitude of swelling pressure which occurs at the contact point of two surfaces shows that with the decrease in the initial load force, there is an

144 increased rise in swelling pressure, especially in phase IIa. The swelling pressure increases as the initial load decreases (Fig. 11 and 12).

Figure 12. Size of swelling occurring between two surfaces connected by a square joint, at a preload of 0.1; 0.2; 0.3; 0.36 and 0.52 MPa after 55 hours of testing

Figure 13. Swelling pressure depending on the different ways of forming the surfaces to be joined by a square joint at a preload of 0.06 MPa

Higher force acting on the contact surface reduces the process of penetration of moisture into the wood structure, causing throttling of swelling. At the highest tested initial contact load of 0.52 MPa, the swelling pressure decreased over time (Fig. 11). At such a high pressure of the combined surfaces of wood, its structures are significantly compressed, limiting the rate of moisture absorption. Further tests included determination of the swelling pressure occurring at the contact point of surfaces formed with various methods (Fig. 13) with the initial lowest load of 0.06 MPa. The highest final values of swelling pressure and the highest rate of force increase in the initial stage of humidification were observed for the surfaces formed by grinding and using a thicknesser, characterized surface roughness expressed by Rz in the direction along and across the fibres equal respectively 10.312/14.046 and 20.536/19.053. For these variants, the final values of swelling pressure were 0.51 MPa and 0.53 MPa. For the milled surfaces

145 with a roughness Rz of 8.328/14.504 along and across fibres the swelling pressure was 0.46 MPa and for manually planed surfaces it was 0.43 MPa, for which the roughness Rz for both directions was 12.948/39.901.The rate of force rise after wetting e.g. the ground surfaces was 0.03 MPa/h and the milled surfaces 0.02 MPa/h. In both cases, the intensity of soaking and higher final swelling values were affected by increasing roughness and decreasing wetting angle of the surface. For all the surfaces tested, the joint was sealed at a certain point in time. For samples with ground surface and surfaces planed with a thicknesser, the water leakage ceased from the moment the swelling pressure of approx. 0.50 MPa occurred. In the case of surfaces milled and manually planed, the joint sealing was obtained at the swelling pressure of approx. 0.43 MPa.

A B C D

Figure 14. Moisture penetration through the joint. A – connected to the contact of the samples connected by a square joint prior to moistening, B – moisture penetration directly after pouring water into the vessel, C – after a few hours characteristic moistening of wood zones in the radial direction with moisture penetration through the joint, D – moment of joint tightening and drying of lower zones of the joined elements

The observation of the tightness of the square joint showed that water flowing through the gap moistened the wood zones located in the mainly radial direction (Fig. 14 B, C). The time after which the joint was sealed depended on the initial load and the resulting swelling pressure. For the sum of the initial load and the swelling pressure of less than 0.90 MPa, the joint was sealed after 40 hours and at a total of 0.62 MPa after 20 hours. At the moment of joint sealing, the lower layers of wood dried out (Fig. 14 D). After sealing, the material still partially swelled and the swelling pressure increased but much slower than at the beginning of the test, when the water percolated through the entire joint.

SUMMARY Obtaining a tight square joint between oak wood elements depends on the properties of the surface, resulting from the way in which they are processed and the size of the initial load on the joint. Among the tested methods of machining, the joint sealing for milled surfaces was the fastest. The contact of the surfaces was influenced by their roughness and contact angle. At the highest surface roughness expressed by Rz in the direction along and across the fibres equal 20.536/19.052, characterizing the surfaces formed with a thicknesser, the sealing of the square joint took place at a swelling pressure of about 0.50 MPa. For ground surfaces with a roughness Rz of 10.312/14.046 along and across fibres, the maximum swelling pressure was 0.53 MPa. In other cases, for surfaces finished with manual planing and milling, for which the roughness Rz for both directions was 12.948/39.901 and 8.328/14.504 respectively, sealing took place at a significantly lower swelling pressure ranging from 0,46 MPa to 0.43 MPa. The water percolation through the joint also depended on the wettability of the surface. With a wettability of 17°, which characterises the ground surface, the seepage time over the entire contact cross-section was 30 seconds. For other surfaces with wettability ranging from 30 to 47°, the seepage time was almost ten times longer.

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On the basis of the conducted research it was found that the maximum swelling pressure measured at the contact of two surfaces depended on the size of their initial load. With an increase of the initial load there was a decrease in swelling pressure. At the initial load of 0.36 MPa the maximum swelling pressure was 0.58 MPa and at the initial load of 0.10 MPa the swelling pressure was 0.90 MPa. Exceeding the value of 0.52 MPa of the initial joint load at the joint inhibited the increase of wood swelling pressure. The compression of layers occurring in the joint zone significantly reduced water percolation into the wood.

REFERENCES

1. DOBROWOLSKA E., NIEMZ P.: 2016; Holzfässer und Bottiche für Wein; Annals of Warsaw University of Life Sciences – SGGW, Forestry and Wood Technology 2016, vol. 94, p. 159-167 2. GLIJER L. 2007; Suszenie i parowanie drewna; Wieś Jutra, Warszawa 3. KRAUSS A. (1988); Untersuchungen über der Quelldruck des Holzes in Faserrichtung , Holzforschung und Holzverwertung, 40 (4); S. 65 – 72 4. KRAUSS A., 2004. Swelling pressure of spruce wood along the grain on moistened by humid air or water. Fol. For. Pol. B(35) 5. NIEMZ P., SONDEREGGER W. 2017; Holzphysik. Physik des Holzes und der Holzwerkstoffe. Fachbuchverlag Leipzig im Carl Hanser Verlag München 6. ORLICZ T. (1988); Obróbka drewna narzędziami tnącymi, Wydawnictwo SGGW- AR, Warszawa 7. PAPIEROWSKI S. 1952; Klepki beczkowe i beczki, Państwowe Wydawnictwo Rolnicze i Leśne, Warszawa 8. PERKITNY T. 1951; Badania nad ciśnieniem pęcznienia drewna, Państwowe Wydawnictwo Rolnicze i Leśne, Warszawa 9. PN-55/D-04110:1955. Fizyczne i mechaniczne właściwości drewna – Badanie procentowego udziału drewna wczesnego i późnego 10. PN-84/D-01005:1984. Chropowatość powierzchni drewna i materiałów drewnopochodnych – Terminologia i parametry 11. PN-82/D-04111: Drewno. Oznaczanie skurczu i spęcznienia 12. PN-77/D-04101: Drewno. Oznaczanie gęstości 13. PRZĄDKA W. SZCZUKA J. 1997; Stolarstwo cz. 2, Wydawnictwo Szkolne i Pedagogiczne, Warszawa 14. RACZKOWSKI J. 1960; Anizotropia ciśnienia pęcznienia drewna, Folia Forestalia Polonica Seria B2; Wydawnictwo Uniwersytet Przyrodniczy w Poznaniu 15. RYBARCZYK W., GANOWICZ R. 1974; A theoretical description of the swelling pressure of wood Published in Wood Science and Technology 1974, p. 233 – 241 DOI:10.1007/BF00352027 16. STEFANIAK J. 1962; Badania nad ciśnieniem pęcznienia drewna w wodzie z zastosowaniem metody przyśpieszonej, Folia Forestalia Polonica Seria B 4; Uniwersytet Przyrodniczy w Poznaniu 17. ŚWIDERSKI J. 1966; Produkcja wyrobów bednarskich h, Wydawnictwo Przemysłu Lekkiego i Spożywczego, Wrocław 18. ŚWITKOWSKI W. 1957; Bednarstwo; Państwowe Wydawnictwo Szkolnictwa Zawodowego, Warszawa 19. ZENKTELER M. 1971; Mechaniczna technologia drewna, PWN, Warszawa

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Streszczenie: Badanie szczelności połączenia na styk elementów z drewna dębowego. W pracy przeprowadzono badanie szczelności połączeń na styk elementów wykonanych z drewna dębowego. Do ustalenia stopnia szczelności tych połączeń zaprojektowano urządzenie, mierzące ciśnienie pęcznienia drewna dębowego pod wpływem nawilżania wodą. Sprawdzanie szczelności połączeń przeprowadzono dla powierzchni uzyskanych w wyniku obróbki skrawaniem poprzez: szlifowanie, frezowanie, struganie grubościowe maszynowe i strugiem ręcznym. Określono również kąt zwilżania wodą powierzchni i ich chropowatość osiąganą w efekcie obróbki skrawaniem. W czasie badania ciśnienia pęcznienia drewna zmieniano wartości wstępnego obciążenia połączeń stykowych. Analiza wyników wykazała, że na szczelność połączenia na styk ma wpływ przede wszystkim chropowatość powierzchni uzyskana w rezultacie obróbki skrawaniem oraz wielkości siły wstępnego obciążenia wywieranego na nawilżane powierzchnie.

Corresponding author:

Ewa Dobrowolska Department of Wood Sciences and Wood Preservation Warsaw University of Life Sciences – SGGW 159 Nowoursynowska St. 02-776 Warsaw, Poland email: [email protected] phone: +48 22 59 38 630

ORCID ID: Dobrowolska Ewa 0000-0003-4176-6005 Karwat Zbigniew 0000-0001-9720-3848

148

Annals of Warsaw University of Life Sciences - SGGW Forestry and Wood Technology № 107, 2019: 149-155 (Ann. WULS - SGGW, For. and Wood Technol. 107, 2019) The borings of Teredinidae in fossil wood of Taxodium Distichum Gothan, 1906

ADAM KRAJEWSKI1, PIOTR WITOMSKI1, ANNA OLEKSIEWICZ2 1 Department of Wood Science and Wood Protection, Warsaw University of Life Sciences – SGGW 2 Department of Physics, Warsaw University of Life Sciences – SGGW

Abstract: The borings of Teredinidae in fossil wood of Taxodium distichum Gothan, 1906. Photographs of borings in fossil wood (Taxodium distichum Gothan, Miocene, Roztocze, Poland) were taken. The texture of the borings surface was analyzed. Moreover, photographs were taken of the surface texture of borings in makore wood (Tieghemella heckelii Pierre) from Africa after Teredinidae and after different species of insects in Scotch pine (Pinus sylvestris L.) for comparative purposes. The photographs were compared. The suspected wood borings in the studied fossil wood of T. distichum were made by mollusc (Teredinidae).

Keywords: fossil wood, Teredinidae, Taxodium distichum

INTRODUCTION The wood borings originate from remnants of numerous animal species such as Insecta: Isoptera, Coleoptera (Cerambycidae, Anobiidae, Bostychidae, Ipidae, Curculionidae), Hymenoptera (Siricidae, Xiphydriidae, Formicidae) in terrestrial environment or Molsusca (Bivalvia: Teredinidae and Pholadidae) and Isopoda found in sea water. Those species not only find shelter in wood but also nourish on it. The wood boring can occur either with or without fungal decay of wood. Frequently, borings can also be found in fossils or carbonated wood. Such wood borings led many researchers to determine types of organisms that caused them, while the wood was still retaining its original properties. The results of those examinations are either of general nature [Kłusek 2006] or more precise to varying degrees [Madziara-Borusewicz 1970, Rajchel and Uchman 1998]. The most abundant fossil wood in Poland are the remains of Taxodium distichum Gothan (Miocene), which are found in Roztocze (south-east of Poland). Recently, those fossilia have been subjected to thorough research [Heflik 1996, Kłusek 2006]. A paper by Kłusek [2006] also signalled the “borings formed due to the activity of wood-eating insects” in fossil wood of T. taxodii. Those facts urged the authors to analyze whether the cause of the damage was wood boring by insects or by Teredinidae (Bivalvia). Teredinidae (Teredo sp., Bankia sp., Nausitora sp.) are a highly specialized bivalve mollusk that drills into wood. Which is significant as Teredinidae are considered an element of marine fauna from the Cretaceous [Finlay and Marwick 1940, Haubold and Daber 1989] or even earlier [Bieda 1966].

MATERIALS The fossil wood of Taxodium distichum Gothan, 1906 from Frampol (Miocene, Roztocze, SE Poland) was used in the research. Its weight was 362 g and the maximum dimensions were 164 x 73 x 25 mm. A natural crack in fossil wood sample exposed the interior of the boring, revealing the surface texture of wood boring wall. The tunnel cross- section is round with a diameter of 9mm (Fig. 1). For comparative purposes, several wood samples were used, including contemporary wood of Scotch pine (Pinus sylvestris L.) damaged by various modern species of wood boring insects and contemporary makore wood (Tieghemella heckelii Pierre, Sapotaceae) from

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Africa, damaged by Teredinidae. The tunnel cross-section is round with a diameter of 4 mm (Fig. 3). The shape of the cross section of Teredinidae borings is round, with a diameter of Y mm. Samples of P. sylvestris wood were split to show the interior of insect borings. Tunnels in Scotch pine were bored by: old house borer larvae (Hylotrupes bajulus L., Coleoptera, Cerambycidae) – oval cross-section 4 x 8 and 18 mm, larvae of Anobium pertinax L. (Coleoptera, Anobidae) – round cross section with diameter 3–4 mm, and larva Siricidae (Hymenoptera) – round cross section with diameter 8mm. Photographs of surface texture of wood boring wall were taken using a camera LUMIX with Leica DC Vario-Elmarit 1:2.8/4.5–108 lens with a light shining in an oblique direction. The surface texture of wood boring wall, which is visible in the pictures, was then compared.

Figure 1. The boring in fossil wood of Taxodium distichum Gothan, 1906

RESULTS The surface texture of wood boring wall in fossil T. taxodii wood is shown in the Fig. 2 and 3. The surface texture of boring wall in makore wood is shown in the Fig. 4.

Figure 2. and 3. The surface texture of wood boring wall in fossil wood of Taxodium distichum Gothan under different lighting

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Figure 4. The surface texture of wood boring wall of Teredinidae in makore wood (Tieghemella heckelii Pierre)

The surface texture of wood boring walls of wood-eating insects has been presented in the subsequent photographs: Fig. 5 – larvae of H. bajulus, Fig. 6 – larvae of A. pertinax, Fig. 7 – larva of Siricidae.

Figure 5. The surface texture of wood boring wall of old house borer (Hylotrupes bajulus L.) in Scotch pine wood (Pinus sylvestris L.)

Surface texture types of wood boring walls can be divided into 2 groups which result from the wood boring method. Insect larvae drill wood with mandibulae. The traces of the wood boring insects’ mandibulae are very numerous and small in relation to the diameter of the tunnel. The surface texture of wood borings walls is therefore rough. Depending on age, population density, wood type and environment, adults size of Teredinidae ranges from a few millimetres to one meter. The shells of Teredinidae are wood-boring instruments. Having small teeth on the valves, the insects use their shells as a rasp. In Teredo sp. adults, the shell is triangular and consists of two parts – the anterior and posterior lobes that are similar in size. Teredinidae drive a tooth into the front of the shell and rub the wood with the front surface of the shell, which is very rough. The front part of the shell grinds the walls of the tunnel. Teredinidae shells leave grinding marks on the walls of the boring. These grinding marks (Fig. 2, 3 and 4) are relatively larger than those of the mandibulae of insects’ larvae (Fig. 5, 6, 7).

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Figure 6. The surface texture of wood boring wall of Anobium punctatum L. in Scotch pine wood (Pinus sylvestris L.)

Figure 7. The surface texture of wood boring wall of Siricidae in Scotch pine wood (Pinus sylvestris L.)

The surface textures of wood boring wall in fossil T. taxodii wood and contemporary makore wood (T. heckelii) are similar. The oval abrasions on the surface of the tunnel walls are similar in diameter size of the tunnels. In the case of H. bajulus (Fig. 5), A. pertinax (Fig. 6), Siricidae (Fig. 7) is completely different. On the surface of the boring walls there are many microscopic traces of the mandibulae of insects larvae. The surface texture of tunnel walls is completely different than in Fig. 2 and 3.

DISCUSSION With respect to the anatomical structure of T. taxodii wood corresponds to the living bald cypress tree (Taxodium distichnum (L.) Rich.) [Kłusek 2006]. Bald cypress is a dominant species of many coastal forested wetlands [Allen et al. 1996]. Modern bald cypresses grow in waterlogged or temporarily flooded stands in warm and humid climatic regions and are the dominant species of coastal forested wetlands. The habitat conditions in Roztocze area were presumably similar when the ancient trees grew there [Kłusek (2006]. Adequate water resources in the case of the Roztocze trees were doubtless connected with the waterlogged nature of their stands [Kłusek 2006]. T. taxodii was similarly

152 a dominant species in forest on temporarily flooded stands. The wood of T. taxodii was often taken into seawater by floods, just like bald cypresses today. Larvae of Teredinidae inhabited such wood. Some modern Teredinidae species exhibit periodic resistance to seawater salinity [Becker, 1958]. The shape and size of tunnels of Tredinidae are very different compared to Pholadidae (Bivalvia, Mollusca) or other animals that make wood borings in sea water [Becker, 1958, Krajewski et Witomski, 2016], while some Isopoda (Sphaeroma hookeri Leach) in seawater can make depressions similar to the borings of cambiophagic insects [Becker, 1961]. Naturally, insects could also drill tunnels in T. taxodii wood. The wood of T. distichnum provides good living conditions to insects, including the old house borer (Hylotrupes bajulus L., Coleoptera, Cerambycidae) [Dominik 1977], which was carried to the United States (Becker1970, Dominik et. Starzyk, 2004). The borings in fossil wood are described as tunnels of insects as most often only fragments of samples are available. Under these conditions, fragments of fossil wood with tunnels of very young Teredinidae can thus be marked, for example, as Anoobidae, and the old ones as Siricidae. Insect remains are rather rare, except for inclusions in amber and asphalt masses. Under favourable conditions the colour of body coatings may also be fixed. Eosilphites decoratus (Coleoptera, Siphidae) (Tertiary, middle Eocene from brown coal lignites at Geiseltal bei Halle in eastern Germany) is a textbook example [Daber et Helms 1988]. Unfortunately, the remains of Miocene xylphagic insects from Roztocze in Poland are not available. We must, therefore, determine the taxonomic affiliation of the animal on the basis of borings in wood. Under these conditions, mistakes are common. An example of changes in the view on insects that caused wood borings from Tertiary was described by Madziara-Borusewicz [1970]. Individual species of xylophagic insects make wood borings of different sizes, different cross-sections and in some cases also a characteristic shape. The wood borings of insects are filled with small scobs and excrement, most often of characteristic shape. The shapes and size of the outlet holes on the wood surface are very helpful in determining the insect species which damaged the wood. However, determining insect species based on wood borings is quite difficult, although included in textbooks [Dominik et Starzyk, 2004, Krajewski et Witomski, 2016]. They are rare in pieces of fossil wood. Round sections of tunnels are found in many species of wood borings insects, for example: Coleoptera (Anobiidae, Bostrichidae, Ipidae, Curculionidae and in the final sections some Cerambycidae, e.g. Corymbia sp. and Monochamus sp.) and Hymenoptera (Siricidae and Xiphydridae). The surface texture of wood boring walls, however, is completely different than in Teredinidae, as shown in Fig. 4, 5 and 6. The borings in fossil wood from Poland are attributed to Sirex sp. (Hymenoptera, Siricidae) and Anobium sp. (Coleoptera) Anobiidae [Rajchel and Uchman 1998] or in the case of carbonic wood Familae of Lymexylonidae, Buprestidae and Ipidae [Madziara-Borusewicz 1970] without analyzing the texture of the wall surface of such a tunnel. The designations of the long sections of wood borings in the paper of Madziara-Borusewicz [1970] most likely present the truth. The designations of wood borings in the paper of Rajchel and Uchman [1998] leave doubts. The tunnels of wood boring insects in carbonic wood are often containing small, compacted scobs. Madziara-Borusewicz [1970] also noticed this. Wood borings of Teredinidae are empty [Becker 1958] except for a short section in front of the animal. This phenomenon was already described in German encyclopaedias in the 18th century [Krajewski et Matejak, 2002]. During the animal’s life, the wall surfaces of Teredinidae tunnels are covered with a layer of calcium carbonate [Becker 1958]. However, the calcium carbonate layer may deteriorate as a result of putrefaction after the animal’s death. Unfortunately, the shells and pallets in modern wood often do not remain fixed. Of course, in the process of fossilization, tunnels can be filled with mineral material or small

153 scobs can also be fossilized. If the surface texture of wood boring wall is inaccessible to view or the interior of the tunnel is filled with mineral substance, it is difficult to determine whether wood borings are left of insects or Teredinidae. When the texture of the walls is visible, it is simple to determine whether they are wood borings left by insects or by Teredinidae.

CONCLUSIONS The wood boring in the studied fossil wood of T. distichum was made by Teredinidae. Studying the surface texture of tunnel walls in fossil wood seems to be an effective way to distinguish wood borings of Teredinidae from those of xylophagic insects.

REFERENCES

1. ALLEN J.A., PEZESHKI S.R., CHAMBERS J.L., 1996: Interaction of flooding and salinity stress on baldcypress (Taxodium distichum). Tree Physiol, 16(1-2):307-313. 2. BECKER G., 1958: Holzzerstörende Tiere un Holzschutz im Meerwasser, Holz als Roh- und Werkstoff, 6, pp. 204–214. 3. BECKER G., 1961: Holzbeschädigung durch Sphaeroma hookeri Leach (Isopoda) an der französischen Mittelmeerküste, Zeitschrift für angewandte Zoologie, 48, pp. 333– 339. 4. BECKER H., 1970: Über die verbreitung des Hausbockkäfers Hylotrupes bajulus L. (Col. Cerambycidae). II Mitteilung, Zeitschrift für angewandte Entomologie, 67, pp. 99–102. 5. BIEDA F., 1966: Paleozoologia, t. 1, Część ogólna. Zwierzęta bezkręgowe, Wydawnictwo Geologiczne, Warszawa. 6. DABER R., HELMS J., 1988: Das grosse Fossilienbuch, Urania–Verlag, Leipzig - Jena – Berlin. 7. DOMINIK J., 1977: Wyniki doświadczeń nad możliwością uszkodzenia drewna cedrzyńca (Calocedrus decurrens Torr.) i cyprysika botnego (Taxodium distichcum Rich.) przez spuszczela pospolitego (Hylotrupes bajulus L.), Sylwan, 10, pp. 25–27. 8. DOMINIK J., STARZYK J.R., 2004: Owady uszkadzające drewno, PWRiL, Warszawa. 9. FINLAY H.J., MARWICK J., 1940: Upper Cretaceous and Tertiary. The Divisions of the Upper Cretaceous and Tertiary in New Zealand, Transactions of the Royal Society of New Zealand, 70, pp. 77–135. 10. HEFLIK W., 1996: Investigation of fossilized trunks from the Roztocze region (in Polish with English summary). Pr. Muz. Ziemi, 44, pp. 127–130. 11. HAUBOLD H., DABER R., 1989: Lexikon der Fossilien, Minerale Und Geologischen Begriffe, Edition Leipzig. 12. KAMPF W.-D., BECKER G., KOHLMAYER J., 1959: Versuche über das Auffinden und den Befall von Holz durch Larven der Bohrmuschel Teredo pedicellata Quatrf. Zeitschrift für angewandte Zoologie, 46, pp. 257–283. 13. KŁUSEK M., 2006: Fossil wood from the Roztocze region (Miocene, SE Poland) – a tool for palaeoenvironmental reconstruction, Geaological Quarterly, 50(4), pp. 465– 474. 14. KRAJEWSKI A., MATEJAK M., 2002: Der Schutz von Teredo navalis L. zur Zeit hölzerner Segelschiffe, Annals of Warsaw University if Life Sciences – SGGW, Forestry and Wood Technology, 52, pp. 123–128. 15. KRAJEWSKI A., WITOMSKI P., 2016: Ochrona drewna – surowca i materiału, Wydawnictwo SGGW, Warszawa.

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16. MADZIARA–BORUSEWICZ K., 1970: Ślady żerowania owadów w lignitach węgla brunatnego w koninie, Folia Foretalia Polonica, Seria B, 9, pp. 107–116. 17. RAJCHEL J., UCHMAN A., 1998: Insect borings in oligocene wood, Kliwa Sandstones outer Carpathians, Poland, Annales Societas Geologorum Poloniae, 68, pp. 219–224.

Streszczenie: Tunele Teredinidae w skamieniałym drewnie Taxodium distichum Gothan, 1906. Wykonano zdjęcia faktury powierzchni ściany tuneli wydrążonych przez Teredinidae w kopalnym drewnie Taxodium distichum z Frampola (Miocen, Roztocze, SE Polska). Dla celów porównawczych sfotografowano tekstury powierzchni ściany tuneli w drewnie makore (Tieghemella heckelii Pierre) z Afryki, pozostałe w sośnie zwyczajnej (Pinus sylvestris L.) po żerowaniu Teredinidae i innych gatunkach owadów. Na podstawie porównania fotografii stwierdzono, że tunel w badanym drewnie kopalnym T. distichum został wydrążony przez Teredinidae.

Corresponding author:

Piotr Witomski Department of Wood Science and Wood Preservation Faculty of Wood Technology Warsaw University of Life Sciences – SGGW Nowoursynowska Str. 166 02-787 Warsaw, Poland e-mail: [email protected] phone: (+48) 22 59 38 655

ORCID ID: Krajewski Adam 0000-0002-6009-6441 Witomski Piotr 0000-0002-8735-2214

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