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1

Experimental investigation and beam-theory-based analytical model of cross-laminated timber panels buckling behavior

Fabrizio Cristiano, Sciomenta Martina, Spera Luca, De Santis Yuri, Pagliaro Stefano, Di Egidio Angelo, Fragiacomo Massimo

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e172, 2023

EN

This paper investigates the buckling behavior of three-layered cross-laminated timber (CLT) panels, from both the experimental and analytical standpoints. Two different series of specimens are considered: the homogeneous ones, which are entirely made of beech, and the hybrid ones, whose inner layers are made of Corsican pine. The experimental tests aim to evaluate the failure limit loads of the specimens, when loaded by an increasing compression tip force. The analytical formulation is first obtained for a panel with a generic number of layers and after it is specialized for a three-layered panel. Timber layers are modeled as internally constrained planar Timoshenko beams linked together by adhesive layers, which are modeled as a continuous distribution of normal and tangential elastic springs. A closed-form solution of the buckling problem is obtained. The achieved Eulerian critical load of CLT panels depends on two parameters, which account for (1) the interaction between timber layers (due to the glue tangential stiffness) and (2) the rolling shear stiffness of the inner layer. Three different failure criteria are introduced to estimate the limit load. Finally, the analytical limit loads and the experimental ones are compared.

2

The impact of abrasive grit size on roughness of sanded beech wood surface

Adamcik Lukas, Kminiak Richard, Dudiak Michał, Banski Adrian

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

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2023

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No. 121

51--60

EN

The study assessed the changing of Ra, Rp, Rv and Rz roughness parameters of the sanded beech surface (Fagus sylvatica L.) as a function of different grit sizes and different measurement direction. The milled samples were ground with a belt sander BS-75 E-set from Festool with belt grit P60, P100 and P150. The sanding belts were Rubin 2 from Festool. Roughness was evaluated using a Keyence VHX-7000 digital microscope. The evaluation length of the roughness measurement was 12.5 mm (λc = 2.5 mm and λs = 8 mm). The R-parameters were measured in accordance with the latest standards ISO 21920 (2022) in the direction parallel to the grain, and in the direction perpendicular to the grain (profile). The paper proves the theoretical assumptions about the reduction of R-parameter values. The measurements showed that the sanded surface was less rough in the direction perpendicular to the grain at P150 sanding belt grit and in the grain direction at P100 grit.

PL

W pracy oceniono zmianę parametrów chropowatości Ra, Rp, Rv i Rz szlifowanej powierzchni buka (Fagus sylvatica L.) w funkcji różnej wielkości ziarna i kierunku pomiaru. Zmielone próbki szlifowano szlifierką taśmową BS-75 E-set firmy Festool o ziarnistościach taśmowych P60, P100 i P150. Taśmy szlifierskie to Rubin 2 firmy Festool. Chropowatość oceniano przy użyciu mikroskopu cyfrowego Keyence VHX-7000. Długość ewaluacyjna pomiaru chropowatości wynosiła 12,5 mm (λc = 2,5 mm i λs = 8 mm). Parametry R zostały zmierzone zgodnie z najnowszymi normami ISO 21920 (2022) w kierunku równoległym do włókien oraz w kierunku prostopadłym do włókien (profil). Artykuł potwierdza teoretyczne założenia dotyczące redukcji wartości parametru R. Pomiary wykazały, że szlifowana powierzchnia była mniej chropowata w kierunku prostopadłym do włókien przy ziarnistości taśmy ściernej P150 oraz w kierunku włókien przy ziarnistości P100.

3

Temperature distribution in beech wood during vacuum drying

Dobrowolska Ewa, Klimczak Andrzej

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

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2021

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No. 116

111--122

EN

Temperature distribution in beech wood during vacuum drying. The temperature distribution and changes in humidity in beech wood in the form of friezes during drying in a vacuum were analysed. The intensity of the occurring phenomena of desorption and the volumetric flow of moisture through the anatomical structures of the wood, depending on the absolute pressure and the temperature of the process, was determined. It was found that the fastest temperature increase took place in the subsurface layers directly adjacent to the heating plates. The introduction of conditioning between the drying phases made it possible to even out the humidity and temperature distribution in the entire element. On the basis of the analysis of changes taking place between the volumes of the three components of wood, it was found that the volume of moisture in the form of vapor removed in the initial phase of drying is over 20 times greater than the volume of voids in wood structures, and in the following phases it decreases to 0.27. The average volume of vapour removed from 1 m3 of wood at the temperature of 55℃ is 13.9 m3/h, decreasing in the following phases to 9.1 m3/h at the drying temperature of 60℃ and then 3.1 m3/h at the temperature of 65℃. The drying rates for these phases reach the value of 0.15%/h, 0.17%/h and 0.075%/h, respectively. Direct measurements of wood moisture, made during the experimental course of the drying process at an absolute pressure of 150 hPa, follow the equivalent moisture, determined on the basis of the Hailwood-Horrobin model, taking into account the appropriate calculation factors.

PL

Rozkład temperatury w drewnie bukowym podczas suszenia próżniowego. Przeanalizowano rozkład temperatury i zmiany wilgotności w drewnie bukowym w postaci fryzów, podczas suszenia w próżni. Ustalono intensywność zachodzących zjawisk desorpcji oraz objętościowego przepływu wilgoci przez struktury anatomiczne drewna, w zależności od ciśnienia bezwzględnego i temperatury przebiegu procesu. Stwierdzono, że najszybszy wzrost temperatury miał miejsce w warstwach przypowierzchniowych bezpośrednio przylegających do płyt grzejnych. Wprowadzenie kondycjonowania między fazami suszenia pozwoliło na wyrównanie wilgotności oraz rozkładu temperatury w całym elemencie. Na podstawie analizy zmian mających miejsce między objętościami trzech składników drewna stwierdzono, że objętość wilgoci w postaci pary usuwanej w początkowej fazie suszenia jest przeszło 20 razy większa od objętości wolnych przestrzeni w strukturach drewna, a w następnych fazach maleje do 0.27. Średnia objętość usuwanej pary z 1 m3 drewna w temperaturze 55℃ wynosi 13,9 m3/h, ulegając w kolejnych fazach obniżeniu do 9.1 m3/h przy temperaturze suszenia 60℃ a następnie 3.1 m3/h w temperaturze 65℃. Szybkości suszenia dla tych faz osiąga wartość odpowiednio 0.15%/h, 0.17%/h i 0.075%/h. Bezpośrednie pomiary wilgotności drewna dokonane podczas eksperymentalnego przebiegu procesu suszenia przy ciśnieniu bezwzględnym równym 150 hPa, nadążają za wilgotnością równoważną, ustaloną na podstawie modelu Hailwooda-Horrobina z uwzględnieniem odpowiednich współczynników obliczeniowych.

4

Colour stability of surface finishes on thermally modified beech wood

Slabejova Gabriela, Šmidriakowá Maria

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

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2021

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No. 114

116--124

EN

Colour stability of surface finishes on thermally modified beech wood. The paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native beech wood and thermally modified wood. At the same time, the colour stability of three surface finishes on the surfaces of native and thermally modified beech wood was monitored. Beech wood was thermally modified at temperature of 125 °C for 6 hours. The thermal treatment was performed in a pressure autoclave APDZ 240, by the company Sundermann s.r.o in Banská Štiavnica. Three various types of surface finishes (synthetic, wax-oil, water-based) were applied onto the wood surfaces. The colour of the surfaces of native wood and thermally modified wood was measured in the system CIELab before and after surface finishing; the coordinates L*, a*, b*, C*ab and h*ab were measured. From the coordinates measured before and after surface finishing, the differences were calculated and then the colour difference ΔE* was calculated. Subsequently, the test specimens with the surface finishes were exposed to natural sunlight, behind glass in the interior for 60 days. The surface colour was measured at specified time of the exposure (10, 20, 30, 60 days). The results showed that the colour of the wood surfaces changed after application of the individual surface finishes; and the colour difference reached a change visible with a medium quality filter up to a high colour difference. The wax-oil surface finish caused a high colour difference on native wood and on thermally modified wood as well. On native beech wood, the lowest colour difference after exposure to sunlight was noticeable on the synthetic surface finish. On the surface of wood thermally modified, after exposure to sunlight, the lowest colour difference was noticeable on the surface with no surface finish.

5

Characteristic of tar content and syngas composition during beech updraft gasification

Kluska J., Kazimierski P., Ochnio M., Kardaś D.

Eco-Energetics : technologies, environment, law and economy

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2019

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T. 2

63--78

EN

This work aims at study the effect of the operating conditions like equivalence ration and temperature on the updraft gasification of beech wood. The main aspects was to analyze the influence of temperature distribution in the reactor and equivalence ratio on the fuel consumption, syngas composition as well as tar formation characteristics during the gasification process. The light tar content and composition were analysed using gas chromatography coupled with mass spectrometry (GC-MS). Experimental results have shown that the amount of air supplied does not affect the parameters of the gasification process linearly. For lower ER value there was high fuel consumption and high bed temperature in the gasifier, which results in high caloric value of syngas. The results showed that tar yield during updraft gasification depends on the temperature and equivalence ratio. With the increase value of ER and the decrease of temperature on the surface of the bed, the total amount of tar yield increased. The highest temperature on the surface of the bed leads to the smallest tar yield, which can be associated with thermal cracking. The results indicate that both light and heavy tar are changing nonlinearly with different operating conditions. In addition, with decreasing temperature and increasing ER values, the amount of phenol and oxidized aliphatic compounds in the tar samples increased while the BTEX amount decreased. The amount of PAHs, in relation to the temperature and ER, was kept low in all cases.

6

Intensification of beech wood drying process using microwaves

Rajewska Kinga, Smoczkiewicz-Wojciechowska Anna, Majka Jerzy

Chemical and Process Engineering

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2019

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Vol. 40, nr 2

179–-187

EN

This paper analyses the influence of the applied microwave power output on the intensification of drying in the context of process kinetics and product quality. The study involved testing samples of beech wood (Fagus sylvatica L.). Wood samples were dried in the microwave chamber at: 168 W, 210 W, 273 W, 336 W and 378 W power output level. For comparison, wood was dried convectively at 40 ◦C and 87% air relative humidity. The analysis of drying process kinetics involved nonlinear regression employing the Gompertz model. Dried samples were subjected to static bending tests in order to specify the influence of the applied microwave power on modulus of elasticity (MOE) and modulus of rapture (MOR). The obtained correlations of results were verified statistically. Analysis of drying kinetics, strength test results and Tukey’s test showed that the applied microwaves of a relatively low level significantly shortened the drying time, but did not cause a reduction in the final quality of dried wood, compared with conventional drying.

7

The effect of UV radiation in Xenotest 450 on the colour of steamed beech wood during the process of simulated ageing

Dzurenda Ladislav

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

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2019

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No. 106

114--120

EN

The effect of UV radiation in Xenotest 450 on the colour of steamed beech wood during the process of simulated ageing .The aim of the paper is to present the changes in colour of steamed beech wood in the pocess of simulated ageing in Xenotest 450. Red-brown colour of beech wood with the coordinates of L* = 62.6 ± 2.8; a* = 10.9 ± 2.3; b* = 17.1 ± 1.3 in the CIE L*a*b* colour space resulted from the mode of colour modification of wood with saturated vapour with the temperature of t = 120 ± 2 oC for τ = 6.5 hours. The surface of samples after drying to the moisture content of w = 12 % and planing was irradiated in Xenotest 450 with xenon gasdischarge tube by UV radiation with the wave length of 340 nm. Accelerated ageing experiment ran in exposure period A1 for seven days. Simulated ageing of thermally treated beech wood showed that due to UV radiation, the wood surface is turning pale and brown. The change in the lightness coordinate by the value of ΔL* = + 6.7 shows the rate of change in the surface lightness and the changes in the values of chromatic coordinates of red colour by the value of Δa* = - 0.1 and yellow colour by Δb* = + 12.3 shows the rate of getting brown. Therefore the hue angle increases from h*ab = 57.5 ° to h°ab = 69.8 °. The value of the total colour difference resulting from the process of ageing is ΔE* = 14.5.

PL

Wpływ promieniowania UV w urządzeniu Xenotest 450 na kolor parzonego drewna bukowego w procesie przyspieszonego starzenia. Celem pracy było przedstawienie zmian barwy parzonego drewna bukowego w procesie przyspieszonego starzenia w urządzeniu Xenotest 450. Czerwono-brązowy kolor drewna bukowego o współrzędnych L* = 62,6 ± 2,8; a* = 10,9 ± 2,3; b* = 17,1 ± 1,3 w przestrzeni barw CIE L*a*b* jest efektem modyfikacji koloru drewna parą nasyconą o temperaturze t = 120 ± 2 oC w czasie τ = 6,5 h. Powierzchnię próbek po wysuszeniu do wilgotności w = 12% i przestruganiu naświetlono promieniowaniem UV o długości fali 340 nm w urzadzeniu Xenotest 450 z lampą ksenonową. Czas ekspozycji wynosił 7 dni. W efekcie procesu przyspieszonego starzenia z wykorzystaniem UV termicznie obrobionego drewna bukowego wykazano, że powierzchnia drewna stała się blada i brązowa. Zmiana współrzędnej jasności o wartość ΔL * = + 6.7 wskazuje na szybkość zmiany jasności powierzchni, zaś zmiany wartości współrzędnych chromatycznych koloru czerwonego o wartość Δa * = - 0,1 i koloru żółtego o wartość Δb * = + 12.3 wslkazują tempo brązowienia powierzchni. Kąt odcienia koloru wzrasta od h*ab = 57,5° do h°ab = 69,8°. Wartość całkowitej różnicy zmiany barw wynikającej z procesu przyspieszonego starzenia wynosi ΔE* = 14,5.

8

Modification of wood by radio-frequency discharge plasma

Novak Igor, Sedliacik Jan, Chodak Ivan, Micusik Matej, Matyasovsky Jan, Jurkovic Peter

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

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2019

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No. 105

85--90

EN

Modification of wood by radio-frequency discharge plasma. Low-temperature plasma was used to improve the surface and adhesive properties of wood. The pre-treatment of wood surfaces using radio-frequency (RF) discharge plasma is attractive for various wood applications, mainly because of the high efficiency and low production cost of the process. The treatment of wood by RF plasma exhibited an aging effect, with the modified surface never recovering its initial hydrophobic state. The contact angle of water decreased with the activation time of the RF plasma treatment.

PL

Modyfikacja drewna za pomocą plazmy RF. W ramach badań wykorzystano plazmę niskotemperaturową wtrwarzaną w generatorach radiowych częstotliwości (plazma RF) do modyfikacji powierzchni drewna pod kątem poprawy jego sklejalności. Wstępna obróbka powierzchni drewna za pomocą plazmy RF może być wykorzystana przy różnych jego zastosowaniach, głównie ze względu na wysoką wydajność i niski koszt procesu modyfikacji. Obróbka drewna plazmą RF wywołała efekt starzenia jego powierzchni. Modyfikacja miała charakter trwały, powierzchnia drewna nie odzyskała swoich początkowych właściwości hydrofobowych. Kąt zwilżania powierzchni drewna wodą zmniejszał się wraz z wydłużeniem czasu aktywacji plazmą RF.

9

Ecomorphological Groups of Earthworms Found in a Beech Wood in the Bieszczady National Park (South-Eastern Poland)

Kostecka J., Mazur-Pączka A., Podolak A., Pączka G., Garczyńska M.

Journal of Ecological Engineering

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2018

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Vol. 19, nr 4

153--158

EN

Earthworms play an important role in the soil quality, including forest soils. Their presence in zooedaphone, as well as their abundance and species diversity, indicate the state of the soil profile. The species diversity of the representatives of this group of macrofauna in a beech forest in the Bieszczady Mountains is recounted in this article. Earthworms were investigated in the soil of four sites selected near Ustrzyki Górne in Carpathian Dentario glandulosae – Fagetum beech woods within the Bieszczady National Park (sites in D. g. Fagetum festucetosum, – typicum, – lunarietosum and – allietosum), every month during the annual cycle during two periods: a/ in 1986–1987 and b/ in 2009–2010. It was done according to the Zicsi’s recommendations, using the Zajonc combinated method, on each site, six 25×25×20 cm samples were extracted. The soil was divided into two layers (0–10 cm and 10–20 cm) and the earthworms were selected manually from them. From deeper layers, they were driven out with a weak (0.4%) formalin solution. In the 1980s, thirteen earthworm species were found (total of 1805 specimens) in the soil of four sites investigated. In a decreasing order of numbers there were: Dendrobaena alpina alpina (Rosa 1984), Allolobophora cernosvitoviana (Zicsi 1967), Aporectodea rosea rosea (Sav.,1826), Aporectodea caliginosa (Sav., 1826), Lumbricus terrestris L., 1758, Octolasium lacteum (Orley,1881), Allolobophora carpathica (Cog., 1927), Fitzingeria platyura montana (Cer., 1932), Octodrilus transpadanus (Rosa, 1884), Dendrobaena octaedra (Sav., 1826), Eisenia lucens (Waga, 1857), Lumbricus rubellus (Hoffm., 1843), Dendrodrilus rubidus tenuis (Eisen, 1874). Twenty years later, in the years 2009-2010, eleven earthworm species were found in the soil of the same four sites investigated (total of 660 specimens). There was no occurrence of L. rubellus, and O. transpadanus. For all the cited species, the vertical distribution dynamics in an annual cycle was investigated as well as the preferred soil layer in terms of soil profile. The features of the afore-mentioned earthworm species and the soil levels they prefer allowed their affiliation with the ecological groups defined by Bouche to be considered or determined. The knowledge on the association of earthworms to ecomorphological groups in natural or a slightly changed ecosystem is becoming very useful, for example at the time of the reclamation of degraded soils with Lumbricidae as bioindicators.

10

The effect of the feed speed and rotation speed of plane milling on the surface roughness of beech wood

Pinkowski G., Szymański W., Krauss A., Stefanowski S.

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

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2018

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No. 103

5--12

EN

The paper presents studies on the effect of feed speed and spindle rotation speed on the milled surface of beech wood worked on a milling machine. In this study eight feed speed variants and five spindle rotation speed variants were tested. The analyses focused on roughness characteristics of milled surface and detailed visual (organoleptic) analyses were conducted. A statistically significant effect of feed speed and spindle rotation speed was observed. Advantageous ranges of beech wood cutting parameters were determined for practical application in milling operations.

11

Strength, modulus of elasticity and density of beech sawn timber in the context of suitability for structural applications

Noskowiak A., Pajchrowski G., Szumiński G., Jabłoński L.

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

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2018

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No. 104

331--337

EN

This paper presents the results of the research on beech sawn timber (Fagus sylvatica L.) with nominal cross-sectional dimensions of 50mm×150mm, produced from the trees harvested in Szczecin Lowland district (Baltic natural-forest region). After testing according to the standard EN 408:2010+A1:2012 and calculating the characteristic values in accordance with the standard EN 384:2016, it was found that beech timber visual graded to the class KW according to Polish standard PN-D-94021:2013 can be assigned to the strength class D30.

12

Quantitative and qualitative yield of beech structural timber (Fagus sylvatica, L.)

Bajza O., Rohanová A.

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

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2018

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No. 104

290--294

EN

Paper analyse qualitative and quantitative yield of beech wood in timber conversion and processing process. Is necessary to evaluate the beech structural timber for application in timber constructions not only according to mechanical properties, but also according to the technological processing. Grading parameters, mainly edgewise and flat wise shrinkage affect its qualitative yield. Tested material consist of 15 tree trunks (21 m-3 ), each was cut into two logs (total 30 logs) further 247 boards (7,4 m-3 ). After processing by planning was boards adjusted to dimension of 50/150 x 3100 mm. Quantitative yield of trunks/boards was 35%. In next step was boards qualitatively graded according to STN 49 1531/Z1, 2006. Of the total number of boards n = 247,118 boards were proved as structural timber (3,5 m-3 ). Qualitative yield of boards/structural timber was 48%. Total yield of trunks/structural timber was 17%.

13

Bending characteristics of beech structural timber (Fagus sylvatica, L.)

Rohanová A., Bajza O.

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

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2018

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No. 104

295--301

EN

Beech wood is a perspective material in building constructions. The design is required to define its characteristic parameters according to EN 338 (2016). Determined through the bending characteristics (bending strength and modulus of elasticity) and density wood. Structural beech timber source in Slovakia was tested by bending test according to EN 408 + A1. The bending characteristics of bending strength, modulus of elasticity (global) were determined on body dimensions (150×50×3000 mm, n = 52, w = 12%). Wood density was measured on small specimens (?408) and boards (?board).The normality of distribution bending characteristics and density wood was evaluated by three independent statistical tests.The tests do not negate the zero hypothesis of the normal distribution of the observed characteristics.The correlation between f408 and Em,g,408 is weak r2 = 0.11.Between the density of wood ?408 and the bending strength fm,408 no correlation has been demonstrated FRÜHWALD (2008), CIBECCHINI et al. (2016).Correlations between the modulus of elasticity (global) and wood density (?board) is significant (r2 = 0.39).The results form the basis for assessing the quality of beech wood in strength classes.

14

Beech wood discoloration induced with specific modes of thermal treatment

Kúdela J., Andor T.

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

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2018

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No. 103

64--69

EN

This work´s study subject is beech wood surface discoloration induced by thermal treatment and by thermo-hydro-mechanical treatment. In the first case, the test specimens were exposed to a 3h heat treatment at temperatures of 160, 180 and 200 °C. In the second experiment, the specimens were pressed (thermo-hydro-mechanical treatment) under various pressing conditions. There was investigated the influence of several pressing parameters (initial moisture content in specimens, pressing time and temperature, compression degree) on wood discoloration. The two treatments caused significant shifts in the colour coordinatesL*, a*, b* with increasing temperature and prolonged treatment time:the lightness decreased significantly, with the a*coordinate shifting to red and the coordinate b* to yellow. These shifts were also reflected in the total colour difference E. The discoloration of the beech wood surface was dependent on the heat energy amount and on its supplying mode, and also close associated with absorbance capacity of the main wood components and with variations in the chemistry of these components.

15

Wytrzymałość na rozciąganie oraz ścinanie drewna dębowego i bukowego zaatakowanego przez owady

Żelazny H., Bednarz B.

Materiały Budowlane

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2017

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nr 5

102--103

PL

Jedną z wad drewna, do których powstania przyczyniają się czynniki biologiczne, są chodniki owadzie, czyli uszkodzenia spowodowane żerowaniem owadów i ich larw. Celem pracy było zbadanie, o ile z powodu wydrążonych chodników może zmniejszyć się wytrzymałość na rozciąganie wzdłuż włókien oraz na ścinanie w poprzek włókien drewna dębowego i bukowego. Do badań porównawczych użyto zdrowego wysuszonego drewna dębowego i bukowego oraz o dość licznych chodnikach głębokich. W ocenie wytrzymałości na rozciąganie wzdłuż włókien elementów z uszkodzoną strukturą przez owady w porównaniu ze zdrowymi odnotowano spadek tej wytrzymałości aż o 59% w przypadku drewna dębowego oraz o 37% w przypadku drewna bukowego. Badanie wytrzymałości na ścinanie w poprzek włókien zarówno drewna dębowego, jak i bukowego wykazało, że wydrążone chodniki nie przyczyniają się do osłabienia wytrzymałości.

EN

One of the disadvantages of wood, caused by biological factors, are larval sidewalks or impairments resulting from feeding of insects. The aim of this study was to examine how much it can decrease strength beech and oak wood due to deep sidewalks. For comparative studies used healthy and dry wood of beech and oak. Used also infected wood of beech and oak with deep sidewalks. Evaluation of the tensile strength along the fibers of the samples damaged by insects showed a decrease of 59% in case of oak wood and reduction of 37% in case of beech wood compared to the healthy wood of these species. Shearing test across the fibers of beech and oak wood showed that hollow sidewalks do not contribute to decrease of strength.

16

Colour changes of beech wood modified with essential oils due to fungal and ageing-fungal attacks with coniophora puteana

Reinprecht L., Hulla M.

Drewno : prace naukowe, doniesienia, komunikaty

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2015

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vol. 58, nr 194

37--48

EN

Fungal attacks on beech wood (Fagus sylvatica L.) samples (25 × 25 × 3) mm were performed using the brown-rot fungus Coniophora puteana over a period of 8 weeks, without or with their previous accelerated ageing in a Xenotest and a drying oven. Due to the fungal and ageing-fungal attacks, respectively, the top surfaces of the reference beech samples obtained a darker yellow-red shade according to the CIE-L*a*b* colour system. Similar changes in the colour coordinates L*, a*, and b* were found for the beech wood modified with the essential oils which were less fungicidal efficient – lavender, sage, tea-tree, and the oil-mixture. On the other hand, the colour changes in the beech wood modified with those essential oils which had a better fungicidal efficiency – birch, clove, oregano, sweet flag, savory, and thyme – were less significant, confirmed by Duncan’s test. Linear correlations with greater or lesser significance were established between the changes in the colour parameters (ΔL*; Δa*; Δb*; ΔE*) and the corresponding mass losses (Δm) of attacked beech wood, the best for positive Δb* which identified its yellowing.

17

The activation energy of swelling beech wood (Fagus sylvatica L.) in water

Moliński W., Kuczyński J., Puszyński J., Roszyk E.

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

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2014

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No. 88

157--161

EN

The activation energy of swelling beech wood (Fagus sylvatica L.) in water. This paper shows the results of the activation energy of swelling beech wood in water. The results showed that activation energy depends on the density. Increasing that values increase activation energy of swelling.

18

Deformation of beech wood – the sources and their identification before beech logs processing

Kúdela J., Gryc V., Tóth V.

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

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2014

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No. 87

121--125

EN

Longitudinal buckling is a very serious problem in production of solid wood panels assembled of beech lamellae joined alternatively breadthwise and longwise into large-sized blocks. The aim of our work was to identify the main factors causing misshaping of beech dowels in solid wood panels production, with the primary focus on identification of reaction tension wood in dowels and logs. According to our results, the most common source of longitudinal buckling of beech dowels was the presence and non-uniform distribution of tension wood in them. The tension wood occurrence in logs is possible to predict with a considerable confidence based on eccentric pith presence. The tension wood presence and distribution over the cross section are possible to identify if the cross-cut surface has been milled and its moisture content reduced under FSP. The tension wood can be discerned through its lighter hue and pearlescent-white gloss.

19

Biotopy i różnorodność gatunkowa Parku Narodowego Jasmund na wyspie Rugia (Niemcy)

Pawełko K.

Ekologia i Technika

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2013

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R. 21, nr 3

112--121

PL

Park Narodowy Jasmund na wyspie Rugia obejmuje obszar leśny Stubnitz, leżącą przed nim plażę wraz z pasem wód Bałtyku oraz nieczynny kamieniołom kredy. Cała powierzchnia parku podzielona jest na dwie strefy. Strefa ochrony ścisłej zajmuje 2600 ha (86.6%). zaś strefa buforowa 403 ha (13.4%). Kreda na Rugii powstała przed około 90 milionami lat jako osad szelfowy. W epoce lodowcowej lądolód przesuwał i wypiętrzał złoża kredy i pozostałe materiały, m.in. glina, margle i piaski. W ten sposób powstało wzniesienie, które stopniowo wypłukiwane jest przez wody Bałtyku. Materiał osadowy zawiera wiele skamieniałości, które łącznie pochodzą od ponad 1000 różnych gatunków roślin i zwierząt. Geologiczne właściwości podłoża są jednym z najważniejszych czynników decydujących o warunkach życia. Spowodowały one powstanie na tym obszarze kilku charakterystycznych biotopów. Jednym z nich jest las porastający kredowe podłoże. Występuje tam buczyna z wyraźną dominacją Fagus sylvatica. W zależności od zróżnicowania warunków siedliska, rosną tam również Acer plataiwides, Sorbus lorminalis. Taxus baccata. Aínassp., Fraxxnus sp.. Ulmiis glabra. Acer pseudoplatanus oraz gatunki dzikich drzew owocowych. Kolejnym biotopem są torfowiska z warstwą torfu o grubości dochodzącej do ponad 11 metrów. Ze względu na ubóstwo pokarmowe liczba żyjących tam gatunków jest niewielka. Na nieco bardziej zasobnych pokarmowo wilgotnych łąkach, występujących w sąsiedztwie torfowisk, bogactwo gatunkowe jest o wiele większe. Znacznie bardziej zróżnicowana jest roślinność runa leśnego. Zależnie od warunków siedliskowych oraz okresu w sezonie wegetacyjnym, występują lam m.in. Anemone nemorosa. A. ranunculoides. A. hepática. Dentaria bulbifera. Harpagopliytum pro cumbens. Cephalanthera sp.. Neotlia nidus-avis i Monotropa hypophegea. Ta wielka różnorodność gatunkowa flory gwarantuje odpowiednie warunki życiowe dla zwierząt. Występują tam ni.in. Dania dama Capreolus capreolus. Sus strofa. Ovis aries musimon. Vulpes vulpes, Meies meles. Mustela putorius. M. niinilis, Martes martes i Nyctereutes procyonoides. W nieczynnych kamieniołomach żyją liczne gatunki nietoperzy, zaś spośród ptaków na uwagę zasługuje Haliaeetus albicUla. Można tam spotkać również relikty glacjalne. np. Rana dalmatina, Crenobia alpina oraz Boloria aquilonaris. Zaprzestanie na terenie parków narodowych gospodarczej ingerencji człowieka umożliwia rozwój przyrody według jej własnych praw i mechanizmów. Tylko w ten sposób będziemy w stanie zachować te obszary dla przyszłych pokoleń w stanie niezmienionym.

EN

The Jasmund National Park on Rugia Island covers the Stubnitz forest area, the beach stretching before it including a strip of Baltic waters and an inoperative chalk quarry. The entire area of the park is divided into two zones. The strict protection zone covers 2600 ha while the protected zone covers 403 ha. Chalk was created on Rugia around 90 million years ago in the form of shelf sediments. In the Ice Age the inland ice moved and uplifted chalk deposits and other materials like clay, marl and sand. In this way an elevation was formed that was gradually washed out by Baltic waters. The sediment material contains many fossils which combined come from over 1000 different plant and animal species. The geological properties of the substratum are one of the most important factors that decide about living conditions. They resulted in the creation of a few characteristic biotopes in this area. One of them is the forest that grows on chalk substratum. Beech woods with a clear dominance of Fagus sylvatica grow there. Depending on the differentiation of settling conditions Acer plalcuioides, Sorbus torminalis, Taxiis baccata. Alnus sp.. Fraxinus sp.. Ulmus glabra. Acer pseudoplatanus also grow there as well as wild fruit tree species. The next biotope is peat with a peat layer of over 11 meters. Because of nutritional poverty only a modest number of species inhabit this area. On slightly nutrition richer damp meadows that exist in the neighborhood of the peats, there is a much larger richness of species. The flora of forest undergrowth is much more diverse. Depending on living conditions and the time of the vegetative season, one of the species that can be found there are i.e. Anemone nemorosa. A. ranunculoides, A. hepatica. Dentaria bulbifera. Harpagophytum procumbens. Cephalanihera sp., Neottia nidus-avis and Monolropa hypophegea. This great diversity of flora species guarantees adequate living condition for animals. Dania dama. Capreolus capreolus. Sus strofa. Ovis aries musimon. Vulpes uulpes. Meies meles. Mustela pulorius. M. nivalis. Martes martes and Nyctereutes procyonoides are one of the examples of species that live there. Inoperative chalk quarries sustain many bat species and among birds Haliaeetus albicilla deserves attention. Glacial relicts like Rana dalmalina. Crenobia alpma or Boloria aquilonaris can be seen there. Halting the economic interference of man in areas belonging to national parks, we allow for the development of nature according to its own laws and mechanisms. Only in this way can we keep these areas in an unchanged slate for future generations.

20

Elastic moduli of veneers in pine and beech plywood

Wilczyński M., Warmbier K.

Drewno : prace naukowe, doniesienia, komunikaty

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2012

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vol. 55, nr 188

47-57

EN

The paper presents the results of a study concerning the elastic moduli of veneers assembled in pine and beech plywood panels. The elastic modulus of veneers in the direction of the grain and the elastic modulus of veneers in the direction perpendicular to the grain were determined by bending plywood strips with their longitudinal axis parallel and perpendicular to the grain of the face plies. The effects of a resin type and the number of veneer plies in the plywood were evaluated. Three- and five-ply plywood bonded with urea and phenol resins were tested. The effect of glue lines in the plywood on the veneer elastic moduli was also evaluated.

PL

Właściwości fornirów w arkuszu sklejki różnią się od ich właściwości w stanie początkowym, przed prasowaniem arkusza. Forniry w sklejce mają większą gęstość, co jest wynikiem ich sprasowania i przesycenia klejem. Znajomość właściwości sprężystych tych fornirów umożliwi analizę naprężeń i odkształceń w elementach konstrukcyjnych wykonanych ze sklejki, w tym stosowanie teorii układów warstwowych. W pracy przedstawiono wyniki badań dotyczących modułów sprężystości fornirów zawartych w sklejce sosnowej i bukowej. Obiektem badań były sklejki trzy- i pięciowarstwowe sklejone klejem mocznikowo- i fenolowo-formaldehydowym. W pierwszej części badań wyznaczono moduły sprężystości przy zginaniu pasm sklejek o osi podłużnej równoległej i prostopadłej do kierunku włókien w obłogach sklejki (rys. 1 i 2). Ich wartości przedstawiono w tabeli 2. Analiza wariancji wykazała, że moduły sprężystości przy zginaniu sklejki zależą od gatunku drewna sklejki, nie zależą natomiast od rodzaju użytego kleju (tabela 3). Na podstawie uśrednionych, dla sklejek z żywicą mocznikowo- i fenolowo-formaldehydową, wartości modułów sprężystości pasm sklejki, obliczono moduły sprężystości fornirów w sklejce: moduł w kierunku włókien i moduł w kierunku prostopadłym do włókien (tabela 4). Pominięto przy tym spoiny klejowe. Dla fornirów w sklejce pięciowarstwowej uzyskano nieco większe, o około 5%, moduły niż dla fornirów w sklejce trzywarstwowej. Moduły fornirów bukowych, zwłaszcza moduł w kierunku prostopadłym do włókien, są większe niż moduły fornirów sosnowych. Stopień anizotropii właściwości sprężystych forniru w jego płaszczyźnie, wyrażony jako stosunek modułu w kierunku włókien do modułu w kierunku prostopadłym do włókien, jest znacznie większy dla forniru sosnowego (około 26) niż dla forniru bukowego (około 16). Oszacowano błąd wynikający z pominięcia spoin klejowych przy wyprowadzeniu wzorów na moduły sprężystości forniru (tabela 5). Okazał się on mały.