Book of Abstracts CSA'19

Page 1


PROGRAM DAY 1 8:30 – 9:00 Registration

9:00 – 9:20 OFFICIAL INAUGURATION Mr. Joan J. Puig, President of Institut Català del Suro 
 Mr. Josep Piferrer, Mayor of Palafrugell
 Mr. Joaquim Ferrer, Secretary of Business and Competitiveness

9:20 – 13:20 1. CORK-WINE INTERACTION (COORDINATION: PAULO LOPES, ENOLOGIST PHD AND WINEMBA) Influence of the cork stopper on the evolution of still and sparkling wine 9:20 – 9:40 Application of hand held near infrared spectrometer in quality assurance of corks
 Jorge Mellado, University Rovira i Virgili 9:40 – 10:10 Contribution of the cork stopper to the aroma of the wine. Positive compounds
 Chantal Prat, Grup Oller 10:20 – 11:20 Coffee Break with posters · Networking 11:20 – 11:40 Migration of polymeric compounds from natural cork stoppers to model wine solution
 Sofia Reis, University of Porto


11:50 – 12:10 Ultrafast analytical method for TCA determination in cork stoppers
 José Juan Rivero, Agilent 12:20 – 12:40 Oxygen transfer through cork stopper
 Thomas Karbowiak, University of Bourgogne 12:50 – 13:10 Behavior of natural cork stoppers when modifying standard corking parameters: Three practical cases
 Cristina Prades, University of Córdoba 13:20 – 15:00 COCKTAIL LUNCH

15:00 – 18:00 2. FUTURE EVOLUTION OF CORK FORESTS (COORDINATION: JOSÉ RAMÓN GONZÁLEZ-ADRADOS, PH.D – UNIVERSIDAD POLITÉCNICA DE MADRID) Trends in the forest management of the cork oak. Impact of climate change on the resilience of forests. New forest management systems to increase their productivity. 15:00 – 15:20 Stem diameter and height as traits linked to cork quality in cork oak
 Augusta Costa, INIAV 15:30 – 15:50 Cork growth under drought conditions
 Vanda Oliveira, University of Lisbon 16:00 – 17:00 Coffee Break with posters · Networking


17:00 – 17:20 Significant genes and processes for cork developement
 Olga Serra, University of Girona 17:30 – 17:50 New forest management techniques to improve the adaptation of cork forest to climate change
 Josep Maria Tusell, Consorci Forestal de Catalunya 18:00 – 18:30 Registration for the Masterclass 18:30 – 19:30



DAY 2 9:00 – 11:30

3. NEW CORK APPLICATIONS IN DESIGN AND CONSTRUCTION(COORDINATION: GABRIEL BARBETA, PH.D – UNIVERSITAT DE GIRONA) Application of the principles of the bioeconomy and circular economy in the use of cork byproducts. 9:00 – 9:20 Cork: new uses in architecture
 Cristina Verissimo, University of Dalhousie 9:30 – 9:50 Corks’s byproduct used as filter media in a treatment wetland for winery wastewater treatment
 Jordi Morató, Universitat Politècnica de Catalunya 10:00 – 10:30 Coffee Break with posters · Networking 10:30 – 10:50 On the development of cork based headband for sports safety
 Ricardo Sousa, University of Aveiro 11:00- 11:20 Study on cork applications in the construction sector
 Pilar Girado, INCAFUST


11:30 – 14:30

4. TECHNOLOGICAL APPLICATIONS: CORK 4.0 (COORDINATION: RICARDO SOUSA, PH.D – UNIVERSITY OF AVEIRO) The use of cork in technological applications using composites or other presentations for the aeronautical, automotive field… 11:30 – 11:50 Pyrolysed cork wastes used for ultra-light-weight microwave adsorbers, EMI shielding or RAM materials
 Robert Pullar, University of Aveiro 12:00 – 12:20 Mechanical response of graphene-enriched agglomerated cork composite under quasi static and dynamic compressive loading
 Fábio Fernandes, University of Aveiro 12:30 – 13:30 Brunch with posters · Networking 13:30 – 13:50 Production of cork hollow pieces by an innovative process based on rotational moulding
 Miguel Pestana, INIAV 14:00 – 14:20 A new 3D filament based in natural biological sources and cork residues
 Flávia Vieira, University of Aveiro

14:30 – 14:45 OFFICIAL CLOSURE Mr. David Mascort Subiranas
 Secretary General of Agriculture, Livestock, Fisheries and Food

14:30 – 15:30 GO Suber Internal Meeting 5



 1.1. Application of hand held near infrared spectrometer in quality assurance of corks - Jorge Mellado…………………………………………………………………………………………………….……………11
 1.2. Contribution of the cork stopper to the aroma of the wine. Positive compounds - Chantal Prat…………………………………….………………………………………….………………………13
 1.3. Migration of polymeric compounds from natural cork stoppers to model wine solution - Sofia Reis………………………………………………….……………………………….…………..………….14
 1.4. Ultrafast analytical method for TCA determination in cork stoppers - José Juan Rivero….……………………………………………………………………………….………………………….………………………15
 1.5. Oxygen transfer through cork stopper - Julie Chanut…………….……………………………..17
 1.6. Behavior of natural cork stoppers when modifying standard corking parameters: Three practical cases - Cristina Prades………………………………………………………21
 1.7. Near-infrared spectroscopy to detect anomalies on plank cork - David PérezTerrazas.……………………………………………………………………………………….………………………….……………………….32
 1.8. Variation on phenolic composition of cork stoppers f rom different geographical origin - Sofia Reis………………………………….……….………………………….……………….……33


 2.1. Stem diameter and height as traits linked to cork quality in cork oak Augusta Costa…………………….…………………………………………………………..……………………………………….……34
 2.2. Cork growth under drought conditions - Vanda Oliveira……………………………………37
 2.3. Significant genes and processes for cork developement - Olga Serra…….……38
 2.4. New forest management techniques to improve the adaptation of cork forest to climate change- Josep Maria Tusell…………………………………………………………….……39
 2.5. Cork oak stands in Spain: Current situation and expected evolution - José Ramón González Adrados………………………………………………………………………………………………….……41
 2.6. Genetic variation of cork oak a tool for improving regeneration of cork oak woodlands - Mª Helena Almeida………………………………….……………………………………………………….42
 2.7. Metodología para realizar estimaciones de producción de corcho - José Berdón………………………………….………………………………………………………………………………………………………..…43
 2.8. Análisis histórico de la calidad de corcho de un grupo de alcornocales de Extremadura - Ramón Santiago………………………………….…………………………………………………….…46
 2.9. Cork quality field assessment and innovative commercialization tools Conceição Santos Silva………………………………….…………………………………………………………………………49
 2.10. Decision making support through spatially distributed valuation: Tunisian cork oak forest’s regulation services - Mariem Khalfaoui…………………………………….………51



3.1. Cork: new uses in architecture - Cristina Verissimo……………………………………….………53
 3.2. Corks’s byproduct used as filter media in a treatment wetland for winery wastewater treatment - Ángel Gallegos…………………………………………………………………….………56
 3.3. On the development of cork based headband for sports safety - Ricardo Sousa……………….…………………………………………………………………………………………………………………………………58
 3.4. Study on cork applications in the construction sector - Pilar Giraldo……………59
 3.5. Study of cork wastewater as a potential source of new tanningels Francisco Javier Yuste……………………………………………………………………………………………………….………61
 3.6. Preliminary investigation on the use of waste cork dust as filler in hot-mix asphalt - Ana María Rodríguez Pasandín…………………………………………………………………………63



4.1. Pyrolysed cork wastes used for ultra-light-weight microwave adsorbers, EMI shielding or RAM materials - Robert Pullar………………………………………………………………………64
 4.2. Mechanical response of graphene-enriched agglomerated cork composite under quasi static and dynamic compressive loading - Fábio Fernandes…………………………………………………………………………………………………………………………………….…66
 4.3. Production of cork hollow pieces by an innovative process based on rotational moulding - Miguel Pestana………………………………………………………………………………67
 4.4. A new 3D filament based in natural biological sources and cork residues Flávia Vieira………………………………………………………………………………………………………………………………….…75
 4.5. Ultra-lighweight cork-geopolymer composites: A sustainable alternative to polymer foams - Rui Novais………………………………………………………………………………….……….…………76
 4.6. Natural energy-absorbing materials applied for vehicle bumper to improve the safety of vulnerable road users - Mariusz Ptak…………………………………………………..……77
 4.7. Crashworthiness of agglomerated cork under the influence of extremely low and high temperatures - Johannes Wilhelm………………………………………………………………..…78


1.1. APPLICATION OF HAND-HELD NEAR INFRARED SPECTROMETER IN QUALITY ASSURANCE OF CORKS † J. Mellado-Carretero*, M. Puxeu•, L. Rodrígez-Saona and S. de LamoCastellví* *Universitat Rovira i Virgili Departament d’Enginyeria Química. Food, Innovation & Engineering Group • Parc Tecnològic del Vi (VITEC) R+D+i Department † Ohio State University Department of Food Science and Tecnology

Keywords: cork stoppers, multivariate analysis, surface treatment, SIMCA Abstract. Cork taint is one of the most concerning problems affecting the cork sector. Because of that, cork-stopper manufacturers proposed several surface treatments with silicone and paraffin in order to improve their sealing behaviour. Several analytical methods such as Gas Chromatography – Mass Spectrometry or extraction with solvents have been proposed to evaluate the quality of stopper surface treatments. However, these methods do not provide information on the homogeneity of the treatment product deposited. Previous studies reported the use of ATR-FT-MIR spectroscopy for detecting the presence and the type of treatment applied to cork stoppers. Nonetheless, mid infrared measurements involve the destruction of the stoppers. The objective of the present work was to determine the presence of surface treatments (silicone) applied to different stoppers in a non-destructive way by using a handheld portable near-infrared system combined with multivariate analysis. Cork stoppers tested were made natural, agglomerated, microagglomerated and mixed microagglomerated-agglomerated for still and sparkling wines. Spectra were collected from twelve spots of each cork stopper using a handheld NIR spectrometer (a Polychromix microPHAZIR). The spectra were collected in the region of 1600 – 2400 nm (6250 – 4167 cm-1) and background spectrum was collected with a highly reflective gold-coated reference material. Multivariate analysis and data preprocessing were performed using a chemometric software (Pirouette version 4.0). Data was mean-centered and transformed with a Multiplicative Scatter Correction (MSC) algorithm. Soft independent modelling of class analogy (SIMCA) was used to build pair-wise models (6 factors, 95%) comprising different silicone-treated and non-treated cork stoppers. 2-classes SIMCA models showed significant chemical differences among treated and non-treated cork stoppers, related to the main components of cork and the presence of silicone (see Figure 1). Bands at 2258 nm (4429 cm-1) could 11

be attributed to Si-O-Si bending from silicone. Another band was observed at 2285-92 nm (4376-63 cm-1) that could be assigned to CH combination bands belonging to the same compound. On the other hand, wavenumbers obtained at 2337 nm (4279 cm-1), 1673 nm (5977 cm-1) and 1927 (5189 cm-1) are due to -CH and -OH groups, respectively, belonging to the cork. To conclude, FT-NIR combined with SIMCA is a powerful tool to rapidly and nondestructively assess the quality of surface-treated cork stoppers. The results provided in the present abstract are promising for the future application of this technique in the cork industry. FIGURES

Figure 1. SIMCA pair-wise Coomans a), class projections b) and discriminating power c) plots of transformed (MSC algorithm) FT-NIR spectra of Non-treated still wine (NTSW) and treated still wine. *Interclass distance (ICD) values greater than 3 are considered significant to discriminate two clusters of samples as a different class.

REFERENCES [1] C. Prades, E. Cardillo-Amo, J. Beira-Dávila, A. Serrano-Crespín, and N. NúñezSánchez, “Evaluation of Parameters that Determine Cork Plank Quality (Quercus suber L.) by Near Infrared Spectroscopy”, Journal of Wood Chemistry and Technology., vol. 0, pp. 1–14, 2017. [2] J. R. Gonzalez-Adrados, M. C. Garcia-Vallejo, M. J. Caceres-Esteban, J. L: Garcia de Ceca, F. Gonzalez-Hernandez, and R. Calvo-Haro, “Control by ATR-FTIR of surface treatment of cork stoppers and its effect on their mechanical performance”, Wood Sci., vol. 46, pp. 349-360, 2012. 12

 *Francisco Oller S.A.

Keywords: Cork stopper, aromatic compounds, vanillin, gas chromatography, Abstract. The influence of washing and heating treatments, implemented in the manufacturing process of cork stoppers, on the positive aromatic compounds present in cork is evaluated. The amount of vanillin and other vanillin related compounds is analysed.

1. INTRODUCTION Cork industry has implemented different treatments aimed to improve the cork stopper’s quality. Most commonly used are washing and heating treatments. These processes not only reduce the presence of off-flavours but also have an influence on the cork’s aromatic profile.

2. MATERIALS AND METHODS Cork discs from different stages of Oller’s manufacturing process are used. Samples were triturated, macerated in hydroalcoholic solution, and analysed by solid phase microextraction (SPE) and mass detector- gas chromatography.

3. RESULTS Heating treatments cause an increase of vanillin and its derivatives due to the degradation of the cork’s lignin matrix. By contrast, washing treatments cause a reduction of vanillin related compounds due to their solubility in water and ethanol.


1.3. MIGRATION OF POLYMERIC COMPOUNDS FROM NATURAL CORK STOPPERS TO MODEL WINE SOLUTION Sofia F. Reis*, Paulo Lopes†, Miguel Cabral†, Nuno Mateus*and Victor de Freitas* * ICETA/REQUIMTE/LAQV- Faculdade de Ciências da Universidade do Porto Departamento de Química e Bioquímica † Amorim & Irmãos S.A. Research & Development

Keywords: Hydrolysable tannins, Condensed tannins, HPLC-DAD/ESI-MS, MALDI-TOF. Abstract. Wine aging in sealed bottles and the contribution of cork stoppers is still not completely understood. Oxygen transfer through cork stoppers despite being an important parameter which affects the organoleptic properties of bottled wine, cannot explain alone the evolution of wines due to the low and limited quantities transferred. Other cork components such as low molecular weight polyphenols and some hydrolysable tannins were also reported to migrate into wine after bottling, which may impact the sensory properties of wine such as odour, flavour and astringency. Tannins have been related to the astringency and bitterness of wines due to their ability to bind salivary proteins owing the formation of tannin-protein complexes by aggregation and/or precipitation. A wide distribution of tannins is expected on genus Quercus, however there are few identified tannins in cork. 
 The aim of this work was to identify the tannins present in cork which were suitable to migrate from natural cork stoppers to wine model solution. The major tannins family identified in the migrated material was hydrolysable tannins with 24 compounds tentatively identified by HPLC-DAD/ESI-MS such as gallotannins, simple ellagitannins, C-glycosidic ellagitannins, complex ellagitannins and oligomeric ellagitannins. Other complex ellagitannins such as glycosylated structures up to DP3 were tentatively identified by MALDI-TOF as well as a glycosylated dimer of gallocatechin linked to vescalagin/ castalagin, the first condensed tannin identified in cork. The migration of these tannins from natural cork stoppers into wine model solutions likely change wine properties, however further work needs to be done to evaluate their impact on the in-bottle evolution of wine.


 JOSE JUAN RIVERO MARABÉ*, LUCA GODINA † * Product Specialist at Agilent Technologies Spain S.L. † Application Specialists in COE at Agilent Technologies Germany

Keywords: Ultra-FastGC, cork, Off-Flavours, Mass Spectrometry, TCA 1. INTRODUCTION The method for the determination of 2,4,6-trichloroanisole (TCA) provide to the wine from the stoppers quantifies the TCA levels released by a sample of stoppers by maceration in a hydroalcoholic solution. This method seeks to evaluate in an ultra-rapid method the risk of cork stoppers being analyzed and providing a methodology in order to control the quality of cork stoppers, taking advantage of new technologies appeared in the sample preparation and also in chromatographic separation and selectivity in detection. 2. GENERALITIES The proposed method seeks to simulate the migration phenomena of 2,4,6trichloroanisole (TCA) as occur between the cork stopper and the bottled wine. The cork stoppers are digested in a wine or a hydroalcoholic solution until equilibrium is reached. One aliquot of TCA is extracted from the headspace part of the sample applying a solid phase microextraction technique (SPME), and analyzed by gas chromatography, with detection by tandem mass spectrometry (GC / MS / MS). In order to obtain the best results regarding sensitivity and selectivity. Traditional cork TCA methods has problemas regarding the a minimum chromatographic analysis time of around 50 minutes, including around 20-30 minutes of fiber sampling. With the development in the market of new types of fibers that can reach the state of equilibrium more quickly between the gas phase and the solid phase (fiber), we are opened the door to be able to decrease this part of the analysis until 3 minutes, always complying with a robust methodology and sensitive enough for the analysis of TCA. But we could not make an ultra-fast approach if we had behind us a system that was able to perform these separations, the possibilities of use ramps over 100ºC and cooling in a very short time to have the equipment available for the next injection, having the minimum dead time between injections. 15

On the other hand, such fast analyzes it needs detectors capabilities in order to discriminate the target analytes from the matrix, being selective while ultrafast measuring. In this study we tried to show as with an Intuvo 9000 GC system coupled to tandem mass spectrometer and a SPME arrow fiber sampling system, it can perform the analysis of TCA and other off-flavors in less than 1.5 minutes. With this new complete system provide increasing laboratory productivity up to 10-15 times compared to the traditional approaches of this analysis in routine laboratories.

REFERENCES [1] HERVÉ E., PRICE S., BURNS G., Chemical analysis of TCA as a quality control tool for natural corks. ASEV Annual Meeting. 1999, [2] Norme ISO 20752 :2007 Bouchons de liège – Dosage du 2,4,6-trichloroanisole (TCA) relargable [3] M. Sefton and R. Simpson, "Compounds Causing Cork Taint and the Factors Affecting Their Transfer from Natural Cork Closures to Wine- a Review," Aust J Grape Wine Res 11, 226-240 (2005). [4] Stephan Baumann and Kawaljit Tandon, “Sensitive detection of Trichloroanisole (TCA) in wine using triple quadrupole GC/MS/MS”, Agilent Application Note #5590-4968EN [5] Wiebke Kaziur, Amir Salemi, Maik A. Jochmann, Torsten C Schmidt “Automated determination of picogram-per-liter level of water taste and odor compounds using solid-phase microextraction arrow coupled with gas chromatography-mass spectrometry”, Analytical and Bioanalytical Chemistry, March 2019.


1.5. OXYGEN TRANSFER THROUGH CORK STOPPER *† *† ǂ † * J. Chanut , A. Lagorce ,R. Gougeon , JP. Bellat and T. Karbowiak * Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR † Univ. Bourgogne Franche-Comté, Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS 
 ǂ Univ. Bourgogne Franche-Comté, Institut Universitaire de la Vigne et du Vin, PAM UMR 02 102

Keywords: Cork stopper, oxygen transfer, wine oxidation Abstract. The oxygen diffusion coefficient through massive cork stopper was determined using a manometric method. No significant effect of the cork compression was noticeable on oxygen transfer, for a compression corresponding to the one used in a bottleneck for still wine. However, the transfer of oxygen through the cork/bottleneck system was largely higher than through the cork alone. These results therefore highlight the crucial role of the interface between the cork stopper and the glass. 1. INTRODUCTION Oxidation is the main issue related to the shelf life of wine. Many studies published during the last forty years have displayed an interest in the field of wine oxidation [1-5]. This oxidation is mainly driven by the ingress of oxygen through the wine stopper [6, 7]. However, the barrier properties of wine stoppers to gases and the mechanisms involved in the mass transfer are not yet well identified. Since no strong consensus exists concerning the closures performance as a barrier to gas transfer, it is rather complex to predict the resulting amount of oxygen entering the wine as a function of the closure used, and even more the impact on the shelf life of the product [8]. The present research work investigated the oxygen barrier properties of cork stoppers. 2. GENERALITIES A homemade manometric method was used to determine the diffusion coefficient of oxygen through massive cork stoppers. This technique allowed to determine the diffusion through cork stoppers, compressed or uncompressed, as well as compressed in a bottleneck in order to evaluate the diffusion at the glass/cork interface [9-11]. 17

Measurements were carried out on cork stopper wafer at 298K using a pressure difference of 200 hPa (200 hPa at on side of the sample and 0 hPa at the other side). The diffusion coefficient of the full-length stopper was then calculated using an extrapolation model (Figure 1). This allows to reduce the experimental time. 3. FIGURES

Figure 1: Extrapolated distribution (black line) of the logarithm of the effective oxygen diffusion coefficient corresponding to a whole massive cork stopper (of 48 mm length), calculated from the experimental distribution measured on a 3 mm thickness massive cork wafer, at 298 K (red line).

Figure 2: Experimental distribution of the logarithm of the effective diffusion coefficient of oxygen in a 6 mm thickness compressed massive cork wafer at 298 K (green bars; n = 17). The purple line is the Gaussian distribution adjusted to these experimental data. The extrapolated distribution to a 48 mm stopper from these data is shown as a red line. The extrapolated


distribution of a 48 mm non-compressed massive cork obtained from an experimental distribution measured on 3 mm massive cork wafers (n = 15) was also added as a black line.

Figure 3: Experimental distribution of the logarithm of the effective diffusion coefficient of oxygen in a full massive cork stopper (49 mm length) compressed in a glass bottleneck at 298 K (orange bars; n = 17). The blue line is the Gaussian distribution adjusted to these experimental data. The extrapolated distribution of a 48 mm compressed massive cork obtained from an experimental distribution measured on 6 mm massive cork wafers, for which the interface around cork was stuck (n = 15), was also added as a red line.

4. CONCLUSION The compression of massive cork stopper (23 % of diameter reduction for still wine), has no significant impact on the oxygen diffusion (Figure 2). However, it is worthy to note that the transfer of oxygen through the cork/bottleneck system is higher than through the massive cork alone. It thus seems that the interface cork/glass bottleneck is the main route for the ingress of oxygen on wine (Figure 3). REFERENCES [1]. T. Karbowiak, R.D. Gougeon, J.B. Alinc, L. Brachais, F. Debeaufort, A. Voilley, and D. Chassagne, "Wine oxidation and the role of cork". Crit. Rev. Food Sci. Nutr. vol. 50, no.1, pp. 20-52, 2010 [2]. H. Li, A. Guo, and H. Wang, "Mechanisms of oxidative browning of wine". Food Chem. vol. 108, no.1, pp. 1-13, 2008 [3]. C.M. Oliveira, A.C.S. Ferreira, V. De Freitas, and A.M.S. Silva, "Oxidation mechanisms occuring in wines". Food R. Int. vol. 44, no.5, pp. 1115-1126, 2011 [4]. C. Roullier-Gall, D. Hemmler, M. Gonsior, Y. Li, M. Nikolantonaki, A. Aron, C. Coelho, R.D. Gougeon, and P. Schmitt-Kopplin, "Sulfites and the wine metabolome". Food Chem. vol. 237, pp. 106-113, 2017 [5]. V.L. Singleton, E. Trousdale, and J. Zaya, "Oxidation of wines I. Young white wines periodically exposed to air". Amer. J. Enol. Vitic. vol. 30, pp. 49-53, 1979 [6]. C. Roullier-Gall, M. Witting, F. Moritz, R.B. Gil, D. Goffette, M. Valade, P. Schmitt-Kopplin, and R.D. Gougeon, "Natural oxygenation of Champagne 19

wine during ageing on lees: A metabolomics picture of hormesis". Food Chem. vol. 203, pp. 207-2015, 2016 [7]. M.A. Silva, M. Julien, M. Jourdes, and P.L. Teissedre, "Impact of closures on wine post-bottling development: a review". Eur. Food R. Technol. vol. 233, no.6, pp. 905-914, 2011 [8]. K. Crouvisier-Urion, J.-P. Bellat, D.R. Gougeon, and T. Karbowiak, "Gas transfer through wine closures: A critical review". Trends Food Sci. Technol. vol. 78, pp. 255-269, 2018 [9]. A. Lagorce-Tachon, T. Karbowiak, C. Paulin, J.M. Simon, R. Gougeon, and J.P. Bellat, "About the role of the bottleneck/cork interface on oxygen transfer". J. Agric. Food Chem. vol. 64, no.35, 2016 [10]. A. Lagorce-Tachon, T. Karbowiak, J.M. Simon, R. Gougeon, and J.P. Bellat, "Diffusion of Oxygen through Cork Stopper: Is It a Knudsen or a Fickian Mechanism?". J. Agric. Food Chem. vol. 62, no.37, pp. 9180-9185, 2014 [11]. S. Lequin, D. Chassagne, T. Karbowiak, J.M. Simon, C. Paulin, and J.P. Bellat, "Diffusion of oxygen in cork". J. Agric. Food Chem. vol. 60, no.13, pp. 3348-3356, 2012


 1*Departamento de Ingeniería Forestal – Universidad de Córdoba Campus de Rabanales
 2Centro de Investigación Forestal – CIFOR
 Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria – INIA

Abstract. In the elaboration of wine many factors directly affect the quality and properties of the final product, among them the choice of bottle and stopper. Standard cork stoppers measure 24 mm in diameter. This dimension determines the thickness or minimum caliper of the cork on the tree, which should be approximately 29 mm for the manufacture of one-piece natural cork stoppers. In Spain, an average of 54,614 tons of cork were produced per year in the period 2006–2013. However, both the thickness and quality of the cork has decreased, thus affecting the percentage of cork that can be used to manufacture natural stoppers, as well as the quality of the stoppers produced. This declining trend could be stabilized or reversed when new cork plantations enter into production following the reforestation of agricultural land. This work aims to address a current need that has arisen in the sector: to increase the percentage of cork stoppers of sufficient caliper and quality for the manufacture of one-piece natural stoppers. In order to increase the quantity of cork suitable for manufacturing natural stoppers, it is necessary to modify the corking diameters by reducing the diameter of the stopper and the compression rate, while ensuring the impermeability of the cork to liquids and gases. Keywords: Cork, bottleneck diameter, stopper diameter, compression rate, compression force, relaxation force, diametrical recovery.

1. INTRODUCTION In the elaboration of wine, there are several factors that directly affect the quality and properties of the final product, among them the choice of bottle and the choice of stopper. One-piece natural stoppers are the highest value21

added product manufactured from high-quality cork. The physical and mechanical properties of this natural product make it ideal for sealing fine wines. Standard stoppers are cylindrical in shape, weigh 4 grams and measure 44 mm in length and 24 mm in diameter. It is this last dimension that determines if the cork on the tree is of the sufficient thickness or caliper for the manufacture of one-piece stoppers as the cork bark must have a minimum thickness of approximately 29 mm. Bottling is the last phase of the winemaking process in which the winemaker intervenes. This is a very important phase as the evolution of the bottled wine will depend on the characteristics of the stopper and the bottling practice. The main physical and mechanical parameters of the cork that influence the sealing capacity of stoppers are the density (a parameter of quality), the compression force required to reduce the diameter of the cork to the diameter of the corking jaw, the relaxation force the cork exerts on the bottleneck on insertion, the recovery of the cork diameter and the extraction force necessary for the final consumer to remove the stopper (GonzĂĄlezHernandez et al., 2014). To seal wine bottles, the stopper is compressed in the corking jaw and inserted into the bottleneck. In normal practice, there is a close relationship between the diameter of the bottleneck, the diameter of the stopper and the diameter of the corking jaw. Standard bottlenecks are not completely cylindrical but of a conical, tapered shape. According to European Standard EN 12726 (2000), standard bottlenecks range in diameter and height, from 18.5 Âą 0.5 mm (diameter) at 3 mm (height), 19 mm (average diameter) at 22.5 mm, to 20 Âą 1 mm (diameter) at 45 mm (height). The optimal stopper diameter for still wines corresponding to a standard 19 mm bottleneck is 24 x 44 mm (figure 1).

Figure 1. Bottleneck and cork stopper dimensions for still wines 22

The stopper and jaw diameter are related through the compression rate. In usual bottling practice, corking machines reduce the stopper diameter by 33% (33% compression rate) from 24 to 16 mm in order to insert the stopper into 19 mm bottlenecks. A total of 201,000 tons of cork are currently produced per year worldwide, of which 62,000 tons are produced in Spain (Cork Quality Council, 2015). The average cork production in Spain has decreased from 74,500 to 66,925 and 54,614 tons per year in the periods 1951–1960, 1961–1970 and 2006–2013, respectively (MAPAMA, 1940–1971; MAPAMA 2005–2013). The decrease in cork production refers to both the cork thickness and quality, which has affected the percentage of cork that can be used for manufacturing natural stoppers and the quality of the stoppers obtained. However, this declining trend could stabilize or be reversed. The entry into production of new cork plantations under the framework of the reforestation plan of agricultural lands promoted by the European Union (Council Regulation (EEC) 2080/92 of the Council of 30 June 1992) is expected to increase cork production. In Spain, 83,425 ha. were reforested with cork oak in pure and mixed masses in the period 1993–2000 (Ovando et al., 2007). Climate change is another important factor in the long-term production of cork. The influence of climatic variables on cork growth has been widely documented, with very significant correlations found between production and droughts and the precipitation regime (Ghalem et al., 2018). Recognizing these factors can improve decision- making processes and reduce the negative effects of climate change (Rodney, 2015). Given these circumstances, cork of a smaller thickness or caliper could be considered for the manufacture of one-piece natural cork stoppers. This could increase the amount of cork suitable for natural stoppers, provided that the sealing capacity of the cork is maintained or improved. From a mechanical viewpoint, it is possible to improve sealing quality in three ways. Firstly, by increasing the stopper diameter; a common practice in wineries for the bottling of long-aging wines. Secondly, by selecting higher quality stoppers, which would increase the cork’s capacity for diametrical recovery. And, thirdly, by decreasing the compression rate, which would also increase the capacity for diametrical recovery. Based on the hypothesis that cork production follows a declining trend, the first two options must be ruled out. Therefore, in order to increase the quantity of cork suitable for manufacturing natural stoppers, it would be necessary to modify the diameters involved in the corking process, reducing the stopper diameter and the compression rate to preserve the quality and properties of the wine. 23

This study attempts to address a current need in the cork sector: to increase the percentage of cork of sufficient caliper and quality for manufacturing one-piece natural stoppers. The aim is to evaluate the mechanical behaviour of stoppers during the corking process in three practical cases by reducing the stopper diameter, reducing the bottleneck diameter and reducing the diameter of the corking jaw. This work can be considered a previous step towards establishing the technical criteria to optimize the correlation between corking diameters and the forces that intervene in the corking process.
 2. METHODOLOGY The main objective is to evaluate corking performance when reducing the stopper diameter. In order to ensure that stoppers of a smaller diameter maintain the proper sealing conditions, the diameter of the bottleneck and the compression rate must also be modified. For all three cases, tests will be carried out to determine the effect of the bottleneck diameter, the stopper diameter and the jaw diameter on the corking process, as described below. As an initial hypothesis, we assume three bottleneck diameters: standard bottlenecks of 19 mm in diameter and smaller bottlenecks of 18 and 17 mm in diameter (Table 1). To determine the stopper diameter (SD) from the bottleneck diameter (BD), the simplest approach is to assume a linear relationship (SD = BD +5) or a proportional relationship (24.BD = 19.SD), which are obtained based on a bottleneck of 19 cm in diameter corresponding to the optimal diameter of a 24 cm stopper. However, these relationships cannot be extrapolated. Therefore, in the absence of an established criterion, stopper diameters of 24 mm, 22.5 mm and 5. mm for bottleneck diameters of 19 mm, 18 mm and 17 mm, respectively, will be used (Table 1). Stopper deformation (ε) is directly related to the difference between the stopper diameter (SD) and the bottleneck diameter (BD) [ε = 1 – (SD/BD)] (Pereira, 2007). To ensure correct bottling, a compression rate higher than 33% should not be applied due to the negative effect it has on the elasticity, dimensional recovery and relaxation force of the cork. These negative effects could be offset by increasing the stopper diameter. Similarly, a decrease in the stopper diameter could be compensated by decreasing the compression rate. In order to not over- compress stoppers of a smaller diameter, in this work the compression rate is not estimated as a percentage of the stopper diameter, but from a linear relationship between the jaw diameter (JD) and the bottleneck diameter (BD): 24

JD (mm) = BD – 1.5 mm

Therefore, a compression rate of ≈ 27% should used for the 24 mm and 22.5 mm stoppers and a compression rate of ≈ 25% should be used for the 20.5 mm stoppers (Table 1). Parameters

Practical cases

Number of stoppers




Bottleneck diameter BD (mm)




Stopper diameter SD (mm)


22. 5

20. 5

Jaw diameter JD (mm)

17. 5

16. 5

15. 5

Compression rate (%)




Table 1. Corking diameters and compression rates used in the three pracical cases The experimental material consists of three batches of 30 one-piece natural stoppers of the same quality (Class 1) measuring 44 mm in length and 24, 22.5 and 20.5 mm in diameter for 19, 18 and 17 mm bottlenecks, respectively. Tests were carried out on each batch of 30 stoppers to simulate the corking process and determine the diameters and forces that intervene in the process. ✓ Diameter of cylindrical stopper (SD) (mm) ✓ Recovered diameter (RD) (mm): diameter measured 24 h after the compression force has ceased (maximum value of the recovered diameter if the compression force has ceased and the stopper is not inserted into the bottleneck) ✓ Maximum compression force (CF) (daN): The compression force of the stopper is defined as the radial and perpendicular force that the corking jaws exert on the lateral surface of the stopper, reducing its diameter by a percentage equivalent to the compression rate. ✓ Maximum relaxation force (RF) (daN): The relaxation force is defined as the radial and perpendicular force exerted by the cork stopper on the inner walls of the bottleneck. The maximum relaxation force is exerted by the stopper on the bottleneck on insertion. ✓ Relaxation ratio (RR) (%) ✓ Elastic recovery or diametrical recovery of the stoppers (DR) (%)


The stoppers were acclimated at the INIA-CIFOR Cork Laboratory for a period of 30 days at a temperature of 20ÂşC and a relative humidity of 65% where they acquired a moisture content of approximately 6%. Once acclimated, the diameter of the stoppers was measured in mm and the tests were carried out. Compression Test: The CF (daN) was measured using a corking machine equipped with a load cell (UTILCELL. Model: 650 SNo 460775(02) Emax: 2Tn). The closure diameter of the jaw was selected and the compression and insertion force of the stopper in the bottleneck was measured. The maximum CF was measured and recorded for each stopper (GonzĂĄlez-HernĂĄndez et al., 2014). CF (daN) = maximum compression force Relaxation Test: To measure the RF (daN), the stopper was placed in a bottleneck tube and inserted into a device developed at the INIA-CIFOR Cork Laboratory (Gonzalez Hernandez et al., 2012). The RF exerted by the stopper against the inner walls of the tube is recorded and transmitted via a spindle to a load cell (SENSOCAR, Mod. S-1, Emax. 150 kg. Precision 50 g). The load cell then transforms the RF into an electrical signal which is shown as a value. The fitted stopper remained in the device for 30 minutes and the maximum RF of each stopper was recorded. RF (daN) = maximum relaxation force

Relaxation Ratio (RR, %): The action of external forces on a deformable solid produces energy which is stored in the form of potential energy, thus increasing the internal energy. In an elastic solid, this process is reversible and there is no loss of energy when the effort ceases (Ortiz Berrocal, 2011). The viscoelastic behavior of the fitted stopper is measured by the relaxation ratio (Gonzalez-HernĂĄndez et al., 2014):

đ?‘…đ?‘…(%) = 100

đ?‘…đ??š đ??śđ??š

where CF (daN) is the maximum compression force and RF (daN) is the maximum relaxation force. 26

Elastic Recovery or Diametrical Recovery (DR, %): If the stopper is released from the corking jaw and not inserted into the bottleneck, the stopper recovers its diameter until reaching the maximum value. Twenty-four hours after compression, the DR of the stopper is measured at the same point where the initial diameter of the stopper was measured (SD). DR is calculated as:

đ??ˇđ?‘… (%) =



đ?‘… đ??ˇ

where SD (mm) is the stopper diameter and RD (mm) is the maximum recovered diameter after compression. It is assumed that effective closure is achieved when the relationship between the maximum compression force exerted during bottling and the force exerted by the fitted stopper on the bottleneck remain constant, that is, when the stoppers have the same relaxation coefficient. 3. RESULTS AND DISCUSSION The mean CF values were 196.34 daN, 188.59 daN and 172.37 daN for the 24 mm, 22.45 mm and 20.5 mm stoppers, respectively (Table 2), thus indicating that the CF decreases as the compression rate decreases. The values obtained for the 24 mm stoppers at a compression rate of 27% were lower than those obtained by GonzĂĄlez- HernĂĄndez et al. (2014) and Prades et al. (2014), which were around 230 daN, for stoppers of the same diameter and a compression rate of 33%. For standard bottling values, the compression stress (Ďƒc) applied to the surface contact area in the radial-tangential direction (Ďƒc = E, Îľ) (Pereira, 2007) takes values of ≈ 1 MPa when the stopper is compressed in the corking jaw. The compression stress obtained for the three batches of stoppers are somewhat lower and range from 0.8 to 0.83 MPa, and remain in the same region of the curve corresponding to the densification of the cell.



Variabl e 24 x 44

22.5 x 44

20.5 x 44








SD (m m)


24.36 (0.07)


22.7 (0.06)


20.70 (0.05)


CF (da N)


196.3 4 (26.3)


188.5 9 (20.85 )


172.3 7 (25.03 )


RF (da N)


25.72 (3.28)


22.35 (2.5)


18.98 (2.21)


DR (% )


0.97 (0.01)

0.96-0.9 8

0.97 (0.01)

0.96-0.9 9

0.97 (0.01)

0.96-0.9 9



0.13 (0.01)

0.10-0.1 5

0.12 (0.01)

0.09-0.1 4

0.11 (0.01)

0.09-0.1 3

Table 2. Characterization of stoppers: mean (standard deviation shown in parenthesis) and range for the three batches The relaxation force was measured with the device patented by the INIACIFOR Cork Laboratory (Gonzรกlez-Hernรกndez et al., 2012) and showed mean values of 25.72 daN, 22.35 daN and 18.98 daN (Table 2), which are somewhat lower than those obtained for standard sealing conditions. The relaxation force is not usually measured directly. Other authors (Fortes et al., 2004) have reported values ranging from 40 to 70 daN. These differences are because the test used to determine the relaxation force was different from the one used here. The relaxation ratio values range from 1 when the compression force is equal to the relaxation force (bottleneck diameter = jaw diameter) to 0 when the relaxation force is equal to zero (bottleneck diameter = maximum recovered diameter). The relaxation ratio was 0.13, 0.12 and 0.11 for the 24 mm, 22.5 mm and 20.5 mm cork stoppers, respectively (Table 2). For standard sealing conditions, the relaxation ratio takes values of 0.11. Giunchi et al. (2008) define 28

the resilience index as the ratio between the relaxation area and the compression area of the stress-strain curve and obtained values of 0.24–0.29 for cork stoppers. However, although the concepts are similar, the methodologies are different, so the data are not comparable. The capacity of the stopper to recover its diameter, which is related to the relaxation force, decreases with time, thus affecting the sealing capacity and impermeability of the bottle closure. The average values are 96% under standard sealing conditions. In the three cases tested, the stoppers recovered 97% of their diameter. This is one point higher than standard recovery due to the decrease in the compression rate (Table 2). Elastic recovery is very important in stopper mechanics, and can be considered a measure of the sealing capacity and impermeability of the stopper. Theoretically, a DR of 97% ensures correct sealing conditions for the new diameters (bottleneck and stopper). However, it is not possible to conclude whether the relationship between the diameters corresponds to the optimal situation. 4. CONCLUSIONS The compression and relaxation forces are directly related to the compression rate, and both are found to decrease as the compression rate and diameter decrease. For a compression rate of 27% and 24 mm and 22.5 mm stoppers, the compression force decreases from 196.34 to 188.59 daN, respectively, and the relaxation force from 25.72 to 22.35 daN, respectively. For a 25% compression rate and 20.5 mm stoppers, the compression force is 172.37 daN and the relaxation force is 18.98 daN. A similar relaxation ratio ranging from 0.13, 0.12 to 0.11 was obtained in all three cases. The values obtained for the compression force and relaxation force are somewhat lower than those obtained for standard sealing conditions. The compression stresses are also somewhat lower than the mean stress under standard conditions, but they remain in the same region of the curve corresponding to the densification of the cell. The results of the tests with bottleneck diameters of 19, 18 and 17 mm and compression rates equivalent to BD - 1.5 mm were satisfactory, as a diametrical recovery of 97% was obtained. This is higher than the diameter recovered in standard conditions, thus ensuring the impermeability of the closure. However, it is not possible to conclude whether the ratio between the tested diameters is optimal. The quality of the cork stoppers has not been considered in this work. However, due to the heterogeneity of the material (Anjos et al., 2008), it would be of interest to study the influence of cork quality and density in the relationship between the diameters and forces involved in the corking process. 29

If it is possible to reduce the diameter of stoppers, the impact of the new raw material requirements regarding cork production and the corking process should be assessed. In particular, parameters such as corkage shifts and the debarking height depend to a large extent on the caliper of the cork. In modifying the diameter of cork stoppers, the diameter of the bottlenecks and the compression rate must also be modified. The optimal relationship between stopper diameter and bottleneck diameter should be established based on the mechanical behaviour of natural cork stoppers during the corking process, taking into account the compression (deformation) and relaxation (recovery) forces exerted on the stoppers. This study can be considered a first step in that direction.

ACKNOWLEDGEMENTS This study has been carried out within the framework of the CC13-045 collaboration agreement between INIA-CIFOR and the University of Cordoba, Spain. The authors would like to thank the laboratory technicians Maria Luisa Cáceres Esteban and Lorenzo Ortiz Buiza for their contribution to the work. 5. REFERENCES Anjos O, Pereira H, Rosa ME. 2008. Effect of quality, porosity and density on the compression properties of cork. Holz Roh Werkst 66(4):295–301 Cork Quality Council. 2015. Industry Statistics. Fortes MA, Rosa ME, Pereira H. 2004. A Cortiça. IST Press, Lisboa Ghalem Amina, Barbosa Inés, Bluhraoua Rachid Tarik, Costa Augusta. 2018. Climate signal in cork-ring chronologies: case studies in southwestern Portugal and northwestern Algeria. Tree-ring research 74 (1): 15-27 González-Hernández F, Gonzalez-Adrados JR, Garcia de Ceca JL .2012. Patente de Invención P200901750: Equipo para la medida de la fuerza de relajación de tapones tras el encorchado [Patent of Invention P200901750: Device for the measurement of the relaxation force of stoppers after corking]. González Hernández, F., González Adrados, J.R., García de Ceca, J.L., Sánchez González, M. 2014. Quality grading of cork stoppers based on porosity, density and elasticity. Eur. J. Wood Prod. 72:149-156 Giunchi A, Versari A, Parpinello GP, Galassi S. 2008. Analysis of mechanical 30

properties of cork stoppers and synthetic closures used for wine bottling. J Food Eng 88(4):576–580 MAPAMA 1940 – 1971. ESTADISTICA FORESTAL DE ESPAÑA http://www,mapama,gob,es/es/desarrollo- rural/ estadisticas/forestal_estadistica_forestal_1940_1971,aspx MAPAMA 2005_2013. ESTADISTICA FORESTAL DE ESPAÑA http://www,mapama,gob,es/es/desarrollo- rural/ estadisticas/forestal_anual_otros_aprovechamientos,aspx NORMA UNE-EN 12726 - 2000: Envases y embalajes. Boca para tapón de corcho con un diámetro de entrada de 18.5 mm para corchos y cápsulas de seguridad. Ovando Paola. Campos Pablo. Montero Gregorio. 2007. Forestaciones con encina y alcornoque en el área de la dehesa en el marco del Reglamento (CEE) 2080/92 (1993-2000). Revista Española de Estudios Agrosociales y Pesqueros nº 214 pp 173-186 Pereira H. 2007. Cork: biology, production and uses. Elsevier, Oxford Prades C; Gómez-Sánchez, I; García-Olmo J; González-Hernández F;, González- Adrados JR. 2014. Application of VIS/NIR spectroscopy for estimating chemical, physical and mechanical properties of cork stoppers. Wood Sci Technol 48 (4): 811- 830



Pérez-Terrazas David

1 , González-Adrados José Ramón , Sánchez-González 2 Mariola

1EscuelaTécnica Superior de Ingeniería de Montes, Forestal y del Medio Natural Universidad Politécnica de Madrid 2INIA-CIFOR

Keywords:Cork, NIRS, visual quality, yellow stain, lignified cork Abstract:The aim of this study was to use of near-infrared spectroscopy (NIRS) to detect anomalies on plank cork such as yellow stain or lignified cork. 90 planks cork were selected: ones with the lowest porosity and without any anomaly (pure cork), others with lignified cork clearly present (lignified cork) and others with yellow stain clearly present (yellow stain).In each plank was selected between 1 to 9 measuring areas where spectra were taken making a total of 326 spectra. Spectra were divided randomly and proportionally into reference and test group, with approximately 70% and 30% respectively for each group.The algorithm used to develop the identify method was factorization, using numerous preprocessingsand spectral ranges.The best model was selected taking into account the smallest total reference error and smallest total test error. Results (Ereference= 0% ; Etest= 4.1%) show that NIRS technology allows to detect with great accuracy anomalies on plank cork and has a good discriminate capacity between yellow stain and lignified cork.


 OF CORK STOPPERS FROM DIFFERENT GEOGRAPHICAL ORIGIN * † ‡ ‡ Sofia F. Reis , Vanda Oliveira , Paulo Lopes , Miguel Cabral , Nuno * † * Mateus , Helena Pereira and Victor de Freitas * ICETA/REQUIMTE/LAQV- Faculdade de Ciências da Universidade do Porto Departamento de Química e Bioquímica † Universidade de Lisboa Instituto Superior de Agronomia Centro de Estudos Florestais ‡Amorim & Irmãos S.A, Research & Development

Keywords: Hydrolysable tannins, Phenolic acids, Near Infrared Spectroscopy (NIRS), Multivariate analysis. Abstract. Migration of phenolic compounds from cork stoppers to wine model solution is undoubted, and its impact on the in-bottle evolution of wine is under evaluation. However, this migration is affected by a great variability. The variability of cork chemical composition was reported between and within trees and geographical location. The aim of this work is to study the variation on phenolic composition of cork stoppers from different geographical origins and evaluate the separation of origins by NIRS and multivariate analysis. Eleven geographical origins were selected, and cork stoppers were produced from planks of the same origin. The phenolic composition was determined by HPLCDAD/ESI-MS (SIM mode) and NIRS spectra was acquired. Variability was not overpass by cork stoppers production from planks of the same origin and phenolic composition was not distinguished by geographical origin, which indicates the variability on phenolic composition of cork stoppers is not significantly influenced by geographical origin but probably more related with genetic of plant material as well as tree age and growth conditions. Nevertheless, separation of some origins was achieved by the highest ellagitannins concentration, and correlations between specific spectra regions and phenolic compounds were established, which opens the possibility to use NIRS to determine the amount of specific phenolic compounds of each cork stopper, allowing the selection of cork stoppers to the wine bottle aging.


2.1. STEM DIAMETER AND HEIGHT AS TRAITS LINKED TO CORK QUALITY (THICKNESS AND POROSITY) IN CORK OAK (QUERCUS SUBER L.) A. Costa*1,2 and I. Barbosa2 1Instituto Nacional de Investigação Agrária e Veterinária,I.P. 2NOVA Center for Environmental and Sustainability Research Environmental Sciences and Engineering Department, NOVA University of Lisbon

Keywords: Raw cork planks; Stem profile of cork quality; Linear mixed models Abstract:In cork oak (Quercus suber L.), the cork thickness and porosity have

been reported to decrease along tree stem upwards [1-5]. However, the stem height-cork thickness and stem height-cork porosity relationships at individual tree level are still not clear, and uncertainties remain about trees age (size) effect on these response variables [6]. In this study, we hypothesized that cork thickness and cork porosity parameters are related with trees specific growth patterns; and may have a strong physiological basis, which determines radial growth variations along the stem. To address the stem height-cork quality relationships we have selected and measured 70-cork oak trees, in a cork oak woodland located at Charneca Pliocénica do Ribatejo, in southwestern Portugal. For the selection of trees, with distinct ages (sizes), their stem location at 1.30 m height was previously marked and the stem diameter at breast height (at 1.30 m height) over cork (dbhoc) was measured. Two dbhoc classes were considered: class 1, of trees with dbhoc < 50 cm; and class 2, of trees with dbhoc 50 cm. In each selected tree, it was previously established the sunny side and shady side of the stem for the collection of cork samples in both stem sides, at distinct heights. Afterwards, during the cork harvesting season, the diameter over cork was measured during the collection of the cork samples at fixed heights, at the stem base (0.3 m height) and at 1-m intervals, till the maximum harvesting height in the tree stem. 34

Linear mixed model analyses were used to test for the effects of possible influences on cork growth rates at different locations on the stem [7]. Stem profiles of trees exhibited: (i) a decrease in diameter over cork along the stem height (Fig. 1A); (ii) a stem height-cork thickness relationship, with trees showing a decrease of the cork thickness with the stem height (Fig. 1B); and (iii) a stem height-cork porosity relationship, with trees showing a decrease in the cork porosity, more in relation to the maximum area of the largest pore (Fig. 1C), and less in relation to the porosity coefficient. The results of our analyses have relevance for cork oak studies on: physiological constraints of stem radial growth and; cork quality stem profiles, for the optimization of high quality raw cork (planks) production at tree-level, determining the economic feasibility of cork harvesting [8,9].




Figure1. Stem profiles of the selected cork oak trees. Values along stem locations (height and side) for: A. Diameter over cork (cm); B. Cork thickness (mm); and C. Maximum pore area (mm2).


J.V. Natividade,”O problema da qualidade da cortiça nos sobreirais do norte do Tejo,” Boletim da Junta nacional da Cortiça no. 8, pp. 5–16, 1939 35


J.V. Natividade, “Subericultura,” Ministério da Agricultura, Pescas e

Alimentação, Direcção-Geral das Florestas, Lisboa, 387 pp, 1950 3. G. Montero G, and R. Vallejo, “Variacion del calibre del corcho medido a distintas alturas,” Invest.Agrar. Sist. Recur. For. Vol.1, no. 2, pp.181–188, 1992 4.

C.Taco, F. Lopes, and H. Pereira, “La variation dans l'arbre de l'épaisseur du

liége et du dos des planches de liége pour des chênes-liéges en pleine production,” Ann. Inst. Sup. Agronom. no 49, pp. 209–221, 2003. 5.

F. González, J.R. González, J.L. García de Ceca, and M. González “Variabilidad de los parametros característicos del corcho en plancha con la altura de extracción,” III Congreso Forestal Español “Montes para la Sociedad del Nuevo Milenio” pp.6, 2001.


M.P. Mendes, P. Cherubini, T. Plieninger, L. Ribeiro, and A. Costa, “Climate effects on stem radial growth of

Quercus suber L.: does tree size matter?,” Forestry (in press), 12 pp. doi: 10.1093/ forestry/cpy034 7.

A. Costa et al. (2018) ”Relationships of stem height and diameter at breast

height and cork growth rates,” Eur. J. For. Res, (under submission process) 8.

G. Oliveira, and A Costa, “How resilient is Quercus suber L. to cork harvesting? A review and identification of knowledge gaps,” For. Ecol. Manage. no.270, pp. 257–272, 2012.


A. Costa, and H. Pereira “Influence of cutting direction of cork

planks on the quality and porosity characteristics of natural cork stoppers” Forest systems Vol. 19, no. 1, pp.51-60, 2010.


 C. Leite*, V. Oliveira*, A. Lauw* and H. Pereira* * Instituto Superior de Agronomia Centro de Estudos Florestais

Keywords:Cork; Dendroecology; Pointer years; Climate change; Cork oak management Abstract.Mediterranean climate change forethoughts more frequent and extreme drought conditions as well as increasing temperatures. Montado is among the most economic and ecological valuable forest systems in this region and up to 200 thousand tons of cork are sustainably extracted each year from the cork oak. To study the ecological response of cork growth to drought and the effect of the age of the phellogen on it we have performed a resilience components analysis of cork growth, in a 30-year chronology along 12 sites in the one of the main production areas of the cork oak. The results confirmed that drought reduces cork growth and revealed that more severe droughts affect more trees and increase the reduction on growth. This research also revealed that the age of the phellogen, the site and the tree affect cork growth during and after drought. In fact, the age of the phellogen affects the recovery, the resistance and resilience but not the relative resilience – e.g when the phellogen is under 3 years old, recovery is 17% lower than when phellogen is between 3 to 6 years old. Nevertheless, there are strong evidences that cork oak is very tolerant and resilient to severe droughts. Moreover, we advise forest managers to increase the period between debarkings, mainly if droughts occur in the first 2 years after debarking.


2.3. SIGNIFICANT GENES AND PROCESSES FOR CORK DEVELOPMENT Sandra Fernández-Piñán, Pau Boher, Marçal Soler, Marisa Molinas, Mercè Figueras, Olga Serra
 Laboratori del Suro, Facultat de Ciències Universitat de Girona, Girona, Spain.

Keywords: Cork, transcriptome, genome. ABSTRACT Cork is a water-resistant protective tissue made of suberized cell walls that forms the outer bark of cork oak (Quercus suber). To understand how cork formation is modulated during the seasonal growth, we analysed the genes activated (transcriptome) by RNAseq using the Illumina platform at three different time points, April (cork meristem activation after winter pause), June (maximum growth of the tissue) and July (high tissue growth but under stressful conditions). The genes identified by RNAseq were annotated using the recently sequenced cork oak genome. The monitoring of the global expression of suberin-related functional categories showed that in April the suberin biosynthesis is already activated but it is in June when there is a maximum activity. When comparing statistically the gene expression between months, we observed that the transcriptomes of June/July were similar and highly differed from April. Differential expressed genes were grouped according to their expression pattern in 4 clusters: genetic reprogramming processes and cell proliferation were up-regulated in April while the biosynthesis and the deposition of the typical cork cell wall components (lignin, suberin and terpenes) and polysaccharides were up-regulated in June/July. These results highlight candidate genes that can be relevant for the activation of phellogen and the production of cork, hence providing putative molecular markers for further breeding programmes.


2.4. NEW FOREST MANAGEMENT TECHNIQUES TO IMPROVE THE ADAPTATION OF CORK OAK FORESTS TO CLIMATE CHANGE Authors: Mundet, Roser1; Tusell, Josep M.1; Beltran, Mario2; Piqué, Miriam2; Baiges, Teresa3; Torrell, Antoni4 1: Consorci Forestal de Catalunya 2: Centre de Ciència i Tecnologia Forestal de Catalunya 3: Centre de la Propietat Forestal 4: Forestal Catalana

Keywords: management, adaptation, climate change, forestry, Quercus suber

ABSTRACT Climate change is a serious threat to the conservation of cork oak forests, sustainable cork production and the value chain linked to this product. Mediterranean area is considered the most vulnerable bioclimatic region to climate change (EEA, 2008). The main expected impacts on the cork oak forests are (Pereira et al., 2009, Díaz et al., 2009, Vericat and Piqué, 2012): reduction of water availability, increasing the frequency of large forest fires and more severe and more frequent episodes of pests, especially the case of cork beetle Coraebus undatus. All these impacts will have a clearly negative effects on the economic, environmental and social functions of cork oak forests. At present, Quercus suber forests conservation and their functions go through sustainable forest management, and this is economically supported by cork production and the minimization and reduction of sanitary affections that cause loss of quality product. In this context, new techniques and methods need to be added in the management, from a comprehensive approach, to improve the adaptation capacities to the climatic change of this type of forests. Adaptation strategy is to improve the resistance and resilience of these forests to the main impacts. Forestry is the key tool to improve the structure, functionality and resilience of Quercus suber forests face to climate change. The models implemented in the Life + SUBER project, based on the ORGEST (Vericat et al., 2013), are irregular models with densities adjusted to the station quality with a greater proportion of large diameter trees, also achieving a high coverage of overlays that limits the development of the helioscope scrub and its vertical continuity, reducing the danger of forest fire. Depending on the station quality, they have been selective cuttings and clearing vegetation in different intensities. Of all the implemented actions a detailed technical follow-up has been carried out that has allowed to contrast its effectiveness and propose improvements to these techniques. From the second year of the first performances, differences in 39

the vitality of the trees can already be observed. The response of trees, in terms of growth in diameter, is always greater in managed areas than in control areas without management. At the same time, the answer is greater when selective thinning of the cork oak is done with clearing vegetation that when they are made more intense vegetation control. At the same time, in all clearing vegetation intensities with selective thinning, the growth difference in diameter of the trees is higher in low quality station areas, in front of high quality station areas. REFERENCES: Díaz, M.; Pulido, F. J.; Pausas, J. D. 2009. “9330 Alcornocales de Quercus suber”. En: VV.AA. Bases ecológicas preliminares para la conservación de los tipos de hábitat de interés comunitario en España. Ministerio de Medio Ambiente, y Medio Rural y Marino. Madrid. Pereira, J. S.; Vaz Correia, A.; Joffre, R. 2009. Facing climate change. En: Aronson, J.; Pereira, J. S.; Pausas, J. D. (eds.). Cork oak woodlands on the edge: ecology, adaptive management, and restoration. Island Press. Washington, DC, p. 219226. Vericat, P., Piqué, M., 2012. El cambio global: impactos probables sobre las formaciones de Quercus y gestión para la adaptación. En: Vericat, P.; Piqué, M.; Serrada, R. (eds.). Gestión adaptativa al cambio global en masas de Quercus mediterráneos. Centre Tecnològic Forestal de Catalunya. Solsona (Lleida), p. 29-46. Vericat, P.; Beltrán, M.; Piqué, M.; Cervera, T. 2013. Models de gestió per als boscos de surera: producció de suro i prevenció d’incendis forestals. Sèrie: Orientacions de gestió forestal sostenible per a Catalunya (ORGEST). Centre de la Propietat Forestal. Departament d’Agricultura, Ramaderia, Pesca, Alimentació i Medi Natural. Generalitat de Catalunya.


2.5. CORK OAK STANDS IN SPAIN: CURRENT SITUATION AND EXPECTED EVOLUTION * † González Adrados, J.R. and Sánchez González, M. * MONTES (School of Forest Engineering and Natural Environment), Universidad Politécnica de Madrid † Department of Forest Products Centro de Investigación Forestal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CIFOR)

Keywords: forest inventory, forest map, cork production. Abstract. Data relative to cork oak in Third Spanish National Forest Inventory (1997 – 2007) and the Forest Map of Spain (1986 – 1998) are summarized and analyzed. Comparisons with earlier works allow to detect main tendencies of evolution of these stands, showing important changes in the second half of the XXth century. Main conclusion is that area and number of trees are growing, but cork production is decreasing, due to the lack of silvicultural management and investment.


2.6. GENETIC VARIATION OF CORK OAK A TOOL FOR IMPROVING REGENERATION OF CORK OAK WOODLANDS *Mª H., Almeida1; I., Aranda2; Mª R., Chambel2; F., Costa e Silva1 ; S., Dettori3; C., Faria1; M Rosaria, Filigheddu3; E., Fernández3; A., Khaldi4; Mª Sameiro, Patrício5; Felipe, Perez6; José A., Ramírez - Valiente2 ; Ana Rodrigues1; Teresa, Sampaio1, Mª C., Varela7 1 Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa
 2 Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de. Investigación Forestal, 3Dipartimento di Agraria, Università degli Studi di Sassari, Sardegna, Italia 
 4Institut National de Recherche en Génie Rural Eaux et Forêts (INRGREF) 5 Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança 6 Unit of Forest Genetic Resources. Directorate General of Rural Development, Innovation and Forest Policy. Spanish Ministry of Agriculture, Fisheries and Food. 7INIAV (Retired)

Keywords: cork oak, genetic variability, adaptability, phenotypic plasticity Abstract. The European Academies' Science Advisory Council (2017) reports that the Mediterranean forest is already being affected by climate change (IPCC, 2014) and cork oak woodlands are particularly vulnerable to high-end climate scenarios that go above the Paris Agreement 2° C increase in temperature. Since longer, more frequent, and more intense drought periods are expected, stress caused by the expansion of arid and semi-arid climate will affect the species distribution. Consequently, not only established stands may be prone to tree mortality, but also the current reforestation effort may be jeopardized by low survival rates attributed to the use of unsuitable genetic material. It is expected that, through genetic adaptation and/or phenotypic plasticity, cork oak populations may have developed significant differences in fitness and the traits related to it. In this context, provenance and progeny trials are the best resource of material to assess the variability between and within populations from seed sources sampled in a wide range of locations (stands) covering the geographical distribution of the species. Profiting from the multi-locality provenance and progeny trials belonging to a Network, established in 1998, in the initiative frame of FAIR I CT 0202 for the evaluation of genetic resources of cork oak for appropriate use in breeding and gene conservation strategies”, where 35 cork oak populations covering all the natural distribution area are represented. The provenance trials that where set up in different countries are entering now the age of first debarking and this should allow to have first data about the influence of genetics on production by different site qualities. INCREDIBLE project should document this knowledge and this has been identified as a priority theme for the Cork iNET within the INCREDIBLE project – Innovation networks for Cork, Resins & Edibles ( In this communication we present a summary of the results (interprovenance variability and phenotypic plasticity in growth, survival, phenology and drought tolerance) observed so far in Tunisia, Italy, Spain and Portugal.


2.7. METODOLOGÍA PARA REALIZAR ESTIMACIONES DE PRODUCCIÓN DE CORCHO Berdón Berdón, J.1, Cardillo Amo, E.1, Lanzo Palacios, R.1, Montero Calvo, A.1, Murillo Vilanova, M.1,y Santiago Beltrán, R.1 1 Instituto del Corcho, la Madera y el Carbón Vegetal - CICYTEX. Área de Dehesa, Pastos y Producción Forestal

Keywords: Alcornocal, corcho, repoblaciones, Quercus suber, modelización. Abstract. En este artículo se establece una metodología para estimar producciones de corcho presentes y futuras a escala regional. 1. INTRODUCTION Los alcornocales de la Península Ibérica son los principales suministradores de materia prima del sector industrial del corcho, pero hace falta un mejor conocimiento de su estado actual y producciones a través de los inventarios forestales, que habría que armonizar para poder realizar estimaciones fiables. Los fondos de la PAC han permitido repoblar muchos miles de hectáreas de alcornocal en el suroeste de la Península Ibérica. Algunas de estas repoblaciones han empezado a entrar en producción, pero es necesario conocer con mayor precisión sus producciones futuras. El sector del alcornocal y el corcho necesita conocer con precisión las producciones de corcho presentes y futuras para poder planificar adecuadamente sus trabajos. El sector industrial se encuentra además en una coyuntura de demandas crecientes de manufacturas de corcho que debe satisfacer en función de las producciones de corcho en campo. 2. GENERALITIES En base a la experiencia del equipo de investigación con muestreos en alcornocales en producción, y seguimiento de repoblaciones de alcornoque realizadas fundamentalmente en Extremadura, se va a trabajar sobre una metodología para realizar estimaciones presentes y futuras de producción de corcho, incluyendo temas como inventario forestal, modelización de crecimiento de alcornoque, modelización de la producción de corcho, incidencia de enfermedades y plagas, mortandad y tasa de regeneración del alcornocal, alteraciones en la calidad de corcho y cartografía de calidad y producción de corcho.


3. FIGURES Estimaciรณn de la producciรณn de corcho para el periodo 2022-2048 30000



Tm 15000 10000 5000





corcho plancha














Figura 1: Estimaciones futuras estimaciรณn producciรณn de corcho de las repoblaciones de alcornoque en Extremadura (a modo de ejemplo).

Figura 2: Repoblaciรณn de la PAC en Extremadura.


REFERENCES [1] Bollullos C., 2001. Propuesta de modelos de estimación de la producción de corcho en los alcornocales extremeños. Proyecto fin de carrera. Instituto CMC y Universidad de Córdoba. Mérida y Córdoba. [2] González Montero, J.A. Guerra Montero, M. Santiago Beltrán, M & Santiago Beltrán, R. 2009. Estudio de forestaciones con alcornoque en Extremadura. Revista Foresta Mediterránea. Sevilla. [3] Montero G., 1987. Modelos para cuantificar la producción de corcho en alcornocales en función de la calidad de la estación y de los tratamientos selvícolas. Tesis doctoral. INIA. Madrid. [4] Santiago Beltrán, R. 2013. Estimación de la producción de corcho de las repoblaciones de alcornoque del periodo 1988-2012 en Extremadura. I Congreso Ibérico de la Dehesa y el Montado. Badajoz.


2.8. ANÁLISIS HISTÓRICO DE LA CALIDAD DE CORCHO DE UN GRUPO DE ALCORNOCALES DE EXTREMADURA Santiago Beltrán, R.1, Lanzo Palacios, R. 1 and Prades López, C. 2 1 Instituto del Corcho, la Madera y el Carbón Vegetal - CICYTEX. Área de Dehesa, Pastos y Producción Forestal 2 Departamento de Ingeniería Forestal – Universidad de Córdoba Campus de Rabanales. Edificio Leonardo Da Vinci

Keywords: Corcho, suberoteca, calidad, clima, alcornoque, IPROCOR, selvicultura. Abstract. This document gives the general guidelines for the abstract submitted to Cork Science and Application Conference (

1. INTRODUCTION La calidad del corcho es una de las cuestiones más relevantes para el sector corchero, debido a la dificultad de establecer criterios objetivos y aptos para ser aplicados en diferentes contextos comerciales e industriales. En 1.985, el recién creado Instituto de Promoción del Corcho (IPROCOR) implantó el “Plan de Estimación de la Calidad del Corcho en Campo”, hoy día internacionalmente reconocido, cuya base de datos proporciona información fundamental para su estudio. 2. GENERALITIES El objetivo de este trabajo es analizar en profundidad los factores que influyen en la calidad del corcho, su evolución histórica, su distribución espacial y los factores que la determinan. Para ello, se ha realizado un estudio de 10 alcornocales muestreados en 3 ocasiones consecutivas cada uno de ellos, cuyas muestras están en la Suberoteca del Instituto del Corcho, la Madera y el Carbón Vegetal del CICYTEX (IPROCOR). Se han analizado parámetros específicos de la calidad de corcho y datos meteorológicos de los 9-10 años correspondientes a cada turno de descorche. Se ha realizado una nueva preparación de las muestras, cociendo y escogiendo todas ellas de una forma homogénea, incluyendo como novedad la clase de aspecto (1-7) de cada cala. Se han seleccionado las estaciones meteorológicas más próximas a cada alcornocal, con condiciones fisiográficas similares, y la Agencia Española de Meteorología (AEMET) ha facilitado los datos 46

de temperaturas y precipitaciones. Se han analizado los rangos de las variables climáticas y de calidad de corcho, la evolución de la calidad de corcho a lo largo del tiempo, las correlaciones entre las distintas variables, las variables con más peso en la variabilidad, y se ha realizado una clasificación de las fincas en función de la calidad de corcho. Se analizarán datos dasométricos, selvícolas y fitosanitarios individualizados para cada árbol, en relación con su calidad de corcho. Se presentarán los resultados más relevantes de la calidad de corcho en relación con el clima, la dasometría, la selvicultura y el estado fitosanitario de los alcornoques. 3. FIGURES

Figure 1: Evolution of cork quality over time

4. EQUATIONS Examples: (1)

Q =-0,0243 Y + 55,658

5. TABLES Fincas

Términos municipales

Estaciones meteorológicas


Series de años

Finca 1

Cáceres (Rincón de Ballesteros)



Finca 2




Finca 3


Valencia de las Torres


Finca 4

Alcuéscar - Montánchez



Finca 5




Finca 6

Malpartida de Plasencia

Malpartida de Plasencia


Finca 7




Finca 8




Finca 9

Valencia de Alcántara

Valencia de Alcántara


Finca 10




Table1 : Farms subject of study and definitive meteorological station assigned to each one of them. REFERENCES [1] González Adrados, J.R. 1990. Clasificación territorial y tipificación de alcornocales de Extremadura. Tesis doctoral. ETSI Montes. Madrid.

[2] González Adrados, J.R., González Hernández, R., Calvo Haro, R. 2000. La predicción del calibre de corcho al final del turno y su aplicación al muestreo de la producción. Investigación Agraria, Sistemas y Recursos Forestales 9:363-373. [2] González Montero J.A., 2004. Variación de la producción de corcho en cantidad y calidad en la comunidad de Extremadura. Tesis Doctoral. ETSI Montes. Madrid.


2.9. CORK QUALITY FIELD ASSESSMENT AND INOVATIVE COMMERCIALIZATION TOOLS Silva, C.S. * , Tomé, M. +, Afonso, T. ** , Telles, M.R. ** *UNAC – Forest Mediterranean Union R&D+i Department
 + Centro de Estudos Florestais, Instituto Superior de Agronomia
 Universidade de Lisboa **APFC – Associação de Produtores Florestais do Concelho de Coruche e Limítrofes

Keywords: Cork; cork quality; field assessment; cork transaction platform. Abstract. Cork quality assessment in the field began in 1992 in Portugal through the private forest owners associations with the aim to increase the knowledge on the market price and cork characteristics. Several research projects contribute to the development of a reliable cork assessment methodology [1][2][3], accepted and recognized by the industrials and the forest owners. The sampling methodology is applied before the cork commercialization, mainly in Portugal and in the south of Spain, but the assessment has potential to be used at a Mediterranean scale supporting the landowners during the cork business. This has been identified as a priority theme for the Cork iNET within the INCREDIBLE project – Innovation networks for Cork, Resins & Edibles ( Depending on the objective, cork quality can be expressed through different parameters. Sampling results are different for different parameters, therefore it is important to select which parameter (or parameters) should be the objective of field sampling. Cork quality is mainly a function of porosity (size, number and total pore area) and defects but these characteristics do not seem to be modifiable by management. For industrial purposes, cork thickness at harvest is also an important characteristic for the definition of the cork technological quality. The objective of the sampling is to evaluate cork value in a certain stand, on the basis of its industrial quality, so the parameters of interest are the proportions of each industrial cork quality classes. These classes are combinations of the visual evaluation of porosity and defects with cork thickness at harvest and have different market values.[1] Based on this sampling, in 2010 private forest landowners associations launched the Cork Transaction Platform which purpose is to contribute to the clarification of the cork business, organizing supply in the region and promoting knowledge on cork quality and market. This Platform also aims a closer interaction between industrials (buyers) and the landowners (sellers) with a more irregular contact with the cork market (9 to 9 years). The Cork Transaction Platform is a privileged place for informed marketing


where: producers will have greater and more diverse contact with potential buyers; buyers have easy access to the cork samples allowing them to choose the cork to buy according to the characteristics of their final products (cork stopper, discs, granulates, etc). With this innovative model, the risk associated with the lack of knowledge of the characteristics of the product to be transacted is reduced and maximizes the economic benefits for both parties. The presentation will focus on the current methodology to perform a cork quality field sampling within the cork oak forest, the results obtained on cork thickness, defects and overall quality and the deliverables sent to the landowners. Also we will explain the Transaction Platform organization and the market outputs from the last 9 years.


CORKASSESS – Field assessment and modeling of cork production and quality. Final report. FAIR CT97 1438.

2. Almeida, A., Tomé, J., Tomé, M., 2010. Development of a system to predict the evolution of individual tree mature cork caliber over time. Forest Ecology and Management 260(8): 1303- 1314. 3. Almeida, A., Tomé, M., 2010. Field sampling of cork value before extraction in portuguese 'montados'. Agroforestry systems 79 (3): 419-430. doi: 10.1007/ s10457-009-9260-8.



Research Institute of Rural Engineering, Water and Forests (INRGREF), Ariana, Tunisia 2National Agricultural Research Institute of Tunis (INRAT), Ariana, Tunisia

Keywords: Carbon storage, SDR, Economic Valuation, Mapping ABSTRACT Forests are considered as an important anthropogenic pillar to face the global changes due to the relevance of the regulation services they provide In Mediterranean countries, where the climate changes effects are exponentially increasing, the value of the forests’ ecosystem services is even higher and their preservation is worthier. However, the biophysical and economic value of such services is usually non observable due to their non-use characteristics, leading to their underestimation by decision makers. Thus, for a better guidance of decision making, it is more appropriate to take into consideration the location and climatic situation and define ecosystem services supply values with reference to their spatial distribution. In the present study, carbon storage and Soil erosion services were chosen to be studied at Tunisian cork oak forests level: Ain- Snoussi. The estimation of biophysical and economic value of regulation ecosystem services’ supply was carried with emphasis on their spatial distribution. It is a cumulative multidisciplinary research based on biophysical models results implemented into the Geographic Information System (GIS) to analyze spatial data. The allopathic methodology was applied to estimate the average carbon flow per ha taking into consideration the different types of land covers. The average carbon flow value was estimated applying the average Emission quota price (8€/tC) to the total quantity of carbon flow of 247898,38t giving an average value of carbon per ha of 53€ha. Unlike carbon, sediment retention doesn’t have any market price, the valuation was proceeded applying the Water Economic price, resulting from the application of The residual Valuation assuming that Irrigation is the first activity to be affected from a decrease in Water availability in case of siltation, to the results of sediment retention obtained by RUSLE model simulation (15169,8 m3) gave an estimate of 24€/ha/year. 51

The estimation results support the importance of the regulation services’ importance, presenting 43% of the Total economic value of the studied area while the spatial distribution of the values constitute a solid asset toward an effective management.

REFERENCES Chebil, A., Campos, P., Ovando, O., & Daly-Hassen, H. (2007). The total commercial income from cork oak forest Agroforestry system in the region of Iteimia, Tunisia. In Cork oak woodlands and cork industry: present, past and future. S. ZapataBlanco (Editor). Costanza, e. a. (1997). The value of the world’s ecosystem service and natural capital. Nature. Daly-Hassen, H. C. (2012). Evaluation économique des biens et services des forêts tunisiennes . La Société des Sciences Naturelles de Tunisie ( SSNT ). Daly-Hassen, H., & Ben Mansoura, A. (2009). Private and Social values and their distribution in Tunisian cork oak forests. XIII World Forestry Congress. Buenos Aires: World Forestry Congress. HÄyhÄ, T., Franzese, P. P., Paletto, A., & Fath, B. D. (2015). Assessing, Valuing and mapping ecosystem services in Alpine Forests. Ecosystem Services, 12-23. Heal gm, b. e. (2005). Valuing Ecosystems Services: Toward Better Environmental Decision-Making. . Washington, DC: National Research Council. Makhlouf, M. (2017). Eau virtuelle dans la production agricole en Tunisie : Quantification , valorisation et modélisation économique. Tunis: Université de Carthage. Malinga, R., Gordon, L., Jewitt, G., & Lindborg, R. (2015). Mapping ecosystem services across scales and continents - A review. Ecosystem Services, 57–63. doi:https:// Merlo, M., & Croitoru, L. (2005). Valuing Mediterranean forests: Towards total economic value (2005 ed.). Wallingford, Oxon: CAB Internacional. Potthast, M. D.-h. (2015). Analyse de la vulnérabilité des écosystèmes forestiers tunisiens face au changement climatique et conséquences socio-économiques associées. XIV Congres Forestier Mondial, (p. 8). Durban, Afrique du Sud. Tammi, I., Mustajarvi, K., & Rasinmaki, J. (2016). Integrating spatial valuation of ecosystem services into regional planning and development. Ecosystem Services. Turner, R. K. (2008). The ecosystem services framework and natural capital conservation. . Environmental and Resource Economics 39 , 25–35.


3.1. CORK NEW USES IN ARCHITECTURE CristinaVerissimo Dalhousie University Canada

Keywords: Cork; Sustainable Material; Materials Engineers Design; Architecture; Culture Abstract. Cork usage is one of the most promising trends in sustainable development, due to its unique natural properties, exceptionally good environmental qualities and its high potential to incorporate innovative technology. Today amongst other uses we see cork used as a textile for clothing, in automobile parts, and as a thermal shield in space crafts. This diversity is crucial for the sector's feasibility. However, there is still a lack of information and diffusion within the engineering and architecture sectors; stakeholders lack awareness to use and select cork materials for construction, compared with other competing products. This research plans to explore future cork industry developments, cork recycling and new cork-based materials which are still in various stages of development with enormous potential for construction. We aim to test or adapt them to be used in construction, hoping that in the future there will be greater application in architecture and eventually will contribute to greater sustainability in the construction business as well as the cork sector. This research started in 2014 providing an environment for researchers and architects as well as those in the industry and other interested parties to meet and develop ideas and experiments using cork. This research will create greater bring awareness of the potentialities of cork as sustainable material, and seek possible new uses of cork materials in architecture. Cork is a natural, recyclable, renewable and non-toxic resource, with strong impact in Mediterranean culture and ecosystems for centuries. Recent developments in cork research demonstrate that its application goes far beyond the classical cork-wine cultural relationship that is globally recognized. 1. INTRODUCTION This research started July 2014, with the organization of an international workshop in Lisbon, focused on the use of cork as a material in architecture. It provided an environment for researchers and architects as well as those in the industry and other interested parties to meet and develop ideas and experiments using cork. In the future, it will be a platform for the internationalization of the use of cork as a building envelope material. It runs in a three-year cycle, organized by themes, according to the type of materials/ prototypes that are going to be tested or developed during each workshop. Since cork is a material with enormous potentialities of application, the research 53

was divided into three main subjects: cork as a membrane, cork as a finishing and cork as self-supporting material. 2. GENERALITIES For Workshop One: Year One, July 2014, the topic was the use of Natural Cork – Tradition. The objectives were: 1 - Gain an appreciation and understanding of Cork as a material. 2- Understand traditional methods in the use of Cork and learn from that experience. 3 – Conduct explorations with natural cork or products using only natural cork, to understand its potentialities and possible applications as a building envelope. Extended research was conducted into recycling of residuals of natural cork produced by cork stopper manufacture. These are three examples, of the over 20 experiences developed.

For Workshop Two: Year Two, July 2015, the topic was the use of Cork Composites – Industry. The objectives were understand how some materials or products develop by industry can be adapted for uses in construction. The research concentrated: 1 - to know the industrial cork processing chain and the composite cork products. 2 - Selection and characterization of cork products and their use changes, i.e. with aging and weathering, 3 - Conduct experiences involving the industry, overcoming potentialities of their materials. Extended research was conducted into recycling of residuals of composite cork produced by cork industry. Here are three examples developed:


For Workshop Three: Year Three, July 2016, the topic was New Materials - Future Technologies. Architects have to start looking for natural and sustainable materials for building construction. The research concentrated on: 1 Understand current architectural practices and foreseeing their future needs; 2 Selection of new materials and technologies that can bring new possibilities of use in architecture and product design; 3 - Understand how research and industry can work together to develop strategic possibilities for future applications. Here are three examples developed:

REFERENCES Pereira H. “Cork: Biology, Production and Uses”. Amesterdam: Elsevier: 26-29, 33 -53, 2007 Gil L. “Environmental, sustainability and ecological aspects of cork products for building”. Sci. Technol. Mater. 23, 87–90, 2011. Santos, C. O. & Amorim, A.“Clusters United by Nature: the World of Wine and Cork”, Amorim Group, 29-32, 2008,


3.2. CORK’S BYPRODUCT USED AS FILTER MEDIA IN A TREATMENT WETLAND FOR WINERY WASTEWATER TREATMENT * † † † Ángel Gallegos , Lorena Aguilar , Carme Bosch , Maria Verdum , † † † † Patricia Jove , Carlos A. Arias , Joan de Pablo & Jordi Morató . * UNESCO Chair on Sustainability, Universitat Politècnica de Catalunya † Fundació CTM Centre Tecnològic † Catalan Cork Institute † Department of Biological Sciences, University of Aarhus † Chemical Engineering, Universitat Politècnica de Catalunya-Barcelona Tech

Keywords: cork byproduct; filter media, aerated vertical flow constructed wetlands, Nitrogen removal. Abstract. Different strategies have been engineered to enhance the efficiency of treatment wetlands (TW). The addition supplementary carbon sources to improve Nitrate removal, the use of reactive media to remove specific pollutants or the use of microbial communities to increase performance are some of the examples of recent intensifications [1]. The ECORKWASTE project (LIFE14 ENV/ES/460) combined induced aeration and the use of byproducts from cork industries in order to treat secondary treatment for a winery wastewater. Recycled materials have been successfully used as filter media in treatment wetlands (TW) to remove pollutants from wastewaters. Cork byproducts, especially cork granulates (size from 0.25 to 8 mm), can be used for wastewater treatment considering its biosorbent properties, especially for pollutants such as heavy metals, organics, oil and grease [2]. The project called for building a 14 m2 TW plant, filled with cork granulates -byproducts of cork processing- as a filter medium. The plant was built using 20 ft. shipping containers. The filter bed was 1.4 m deep layer and consisted of a bottom 0.20 m gravel layer (32 mm Ø) engulfing the drainage system, a 1.0 m layer of cork granulates (7 mm Ø) as filter medium, and a top 0.20 m gravel layer (32 mm Ø) engulfing the distribution system. The TW was planted with Phragmites australis at a four plants/m2 density. The pilot operated as a saturated aerated vertical flow treatment wetland. Results from the first period (non-aerated) during September 2017 (when wastewater production peaked), showed removal efficiencies for NT and NO3-N ranging from 21-57% and 26-58%, respectively. Removal efficiencies during the second period (aerated) clearly increased and ranged from 56

64-83% and 92-95% for TN and NO3-N, respectively. The energy consumption in the aerated period was 3.1 kW/h¡d. Both strategies used in the treatment wetland, the induced aeration and the cork byproduct granulates used as a filter medium, were effective for TN and NO3-N removal from wastewater. REFERENCES [1] Aguilar L. (2019) Microbial nitrate removal in groundwater polluted from agricultural activities with hybrid cork treatment wetlands. Science of the total Environment 653, 723-734. [2] Abranches A. (2014), PhD thesis, Use of cork byproducts as sorbents for oil and grease removal from industrial wastewaters. LSRE-Laboratory of Separation and Reaction Engineering - Associate Laboratory LSRE/LCM, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal.



* * † † L.M.M. VARELA , F.A.O. FERNANDES , M. PTAK , JOHANNES WILHELM AND *,1 R.J. ALVES DE SOUSA , * Center for Mechanical Technology and Automation Universidade de Aveiro †Wroclaw University of Science and Technology Faculty of Mechanical Engineering

Keywords: Composite materials, cork, numerical simulation, head safety Abstract.Nowadays, the number of people, infants and adults, that practise team sports involving physical contact has increased. For sports where the use of head protective equipment is not mandatory, some sportsmen use headbands to feel safer. In the market, there are several solutions for this purpose made by synthetic foams that guarantee a level of protection proportional to its mechanical properties. Cork is a natural cellular material capable of absorbing considerable amounts of impact energy [1]. These characteristics make this material ideal for certain applications such as impact protection. In this work, a cork agglomerate with selected suitable density and crashworthiness properties to be incorporated into a protective headband is studied. With this goal in mind, 3 headbands at the market were comparedin order toestablish a protection level where cork should be able to perform as well. Finally, a cork headband model was modelled. For every headband, impact was simulated and kinematics parameters were extracted. The results of these analysis showed that the selected agglomerated cork performed comparable or better performance than some of the foams found in thesecommercial reference devices. [1] Ptak, M., Kaczynski, P., Fernandes, F.A.O., de Sousa, R.J.A. Assessing impact velocity and temperature effects on crashworthiness properties of cork material(2017) International Journal of Impact Engineering, 106, pp. 238-248. DOI: 10.1016/j.ijimpeng.2017.04.014


 * M.P. GIRALDO 1, E. CORREAL1, M. VILCHES 1, S. TEMIÑO1 1 InstitutCatalà de la Fusta (Incafust). Consorci Centre de Ciència i Tecnologia Forestal de Catalunya (CTFC)

Palabras clave: lignocellulosic materials, sustainable construction, ecologic products, insulation materials, low environmental impact. Resumen.This review brings together the main applications of cork in the sustainable construction sector. It forms part of one of the lines of research of the Catalan Institute of wood INCAFUST that aims to promote the benefits of the use of renewable construction materials and low environmental impact, such as wood, its derivatives and other lignocellulosic materials. Cork is a renewable forest product with unquestionable environmental credentials. Its extraction and transformation process suppose a carbon footprint much lower than that of other synthetic construction materials with similar thermal properties like polyurethane foam sheets (PU) and expanded polystyrene (EPS) [1]. In addition, its physicochemical properties make it a high-performance material for different uses in the building. Cork has a peculiar microscopic structure, made up of closed hexagonal cells full of air which provide it excellent insulating properties to water, gas and sound waves. The empty space in the cell tissue is approximately 85-90%, therefore it's a very light material too[2]. The main extractive components that covers the inner cell tissue are suberin and waxes conferring permeability, and phenolic compounds, which seem to play a protective role against the attacks of biological organisms [3]. The growing concern about the deterioration of the planet and the challenges that are posed with international agreements to reduce C02 emissions have stimulated an increasing interest in the renewable resources. Therefore, in recent years, research on renewable materials and products such as cork has been especially active. Many scientific publications with significant information for industry are available. This review includes some fundamentals of cork structure, composition and properties. It also explores the processes for obtaining the raw material and the manufacture of products available in the market such as insulation agglomerated panels and composite products, cladding and projected for facades, coatings for floors and ceilings etc.


REFERENCES [1] B. I. Zabalza, K. E. Easterling, and M. F. Ashby, “Life cycleassessment of building materials: comparative analysis of energyand environmental impacts and evaluation of the eco-efficiency,” Improvement potential. Build environ., 46:1133-1140,2011. [2] R.Texeira, HPereira, “Ultrastructural observations reveal thepresence of channels between cork cells,” MicroscMicroanal., 15(6):539-544, 2009. [3] L.Gil, “Cork as a building material. Technical manual. APCOR,” Santa Maria de Lamas, Portugal, 2007.


 * † F.J. Yuste-Córdoba , J. Beltrán-Heredia *CICYTEX Instituto del Corcho, la Madera y el carbon Vegetal †Universidad de Extremadura (UEx) Departamento de Ingeniería Química y Química Física

Keywords: tanningels, cork wastewater, phenolic compounds Abstract. 1. INTRODUCTION One of the first stages of industrial preparation of cork consists of its immersion for approximately one hour in boiling water, generating A wastewater with high organic pollution. Therefore, the complex nature of the effluent requires sophisticated and efficient treatment processes. On the other hand, tanningels are gelified tannin extracts and they are effective to eliminate some pollutants in effluents (1). As CICYTEX has developed a new treatment for cork boiling wastewater (CBW) by extracting its phenolic compounds (2), this work studied if these extracts can be used as a source of new tannigels to use them for the depuration of polluted effluents. 2. EXPERIMENTAL Three tanningels were obtained treating a phenolic compounds extract from CBW by the following procedures. sulfonation, introduction of functional amine groups and polymerization by formaldehyde. The study of the adsorption capacity of the modified tannins was carried out with several significant indicators: -Two colorants (methylene blue and brilliant blue remazol). -Two heavy metals (Cd2+ and Pb2+). -A detergent (sodium dodecylbenzene sulfonate). -A pharmaceutical compound (trimethoprim) -A pesticide (clopyralid).


3. RESULTS AND DISCUSSIONS. The results showed that the only compounds adsorbed significantly were: -Colorants (up to 79% for Remazol Brilliant Blue and 96,6% for methylene blue). -Heavy metals (up to 82,0% for cadmium and 90,7% for lead). Besides, some of the polymerized products showed a slight solubility in water.

4. CONCLUSIONS Although these results are interesting as regards absorption of colorants and heavy metals, there are some disadvantages: the bad adsorption for organic compounds and a slight solubility in water for some of the polymerized products. Therefore, it is necessary to improve the generation of these tanningels in order to avoid the drawbacks previously cited and to achieve a best perfomance. REFERENCES [1] J. Sánchez-Martín, J. Beltrán-Heredia, P.Gibello-Pérez. Ashby, “Adsorbent biopolymers from tannin extracts for water treatment”, Chemical Engineering Journal, v.168, no.3, 2011 April 15, pp. 1241-1247, 2011. [2] Mehrdad Arshadi et al, “Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain”, J. Mater. Sci., vol. 23, no. 3, pp. 879–885, 1988. Green Chem., 2016,18, 6160-6204.


3.6. PRELIMINARY INVESTIGATION ON THE USE OF WASTE CORK DUST AS FILLER IN HOT-MIX ASPHALT Ana María Rodríguez Pasandín1,*, Juan José Galán Díaz1, Ignacio Pérez Pérez1 1 Universidade da Coruña (UDC). E.T.S.I. Caminos, Canales y Puertos.

Keywords: hot-mix asphalt; waste cork dust; filler; adhesion; moisture damage resistance. Abstract. The cork contains significant amounts of a biopolymer called suberin (45%). Polymers have been frequently used in the manufacture of hot-mix asphalt (HMA) to improve their properties. At the Universidade da Coruña (UDC), a preliminary investigation was carried out in which the feasibility of using waste cork dust from the manufacture of plugs, as filler in the manufacture of HMA was analyzed. Firstly, the aggregate-binder adhesion was analyzed by means of two types of tests: the boiling water test and the rolling bottle method. The performance of the cork filler was compared with the performance of conventional natural filler. In both tests it was obtained that with the cork filler, the aggregate-binder adhesion was better than with the natural filler. Secondly, a HMA type AC 22 bin S was manufactured, with a bitumen content of 3.8%. Indirect tensile test after immersion in water were conducted, in order to compare the moisture damage resistance of mixtures made with filler cork and natural filler. It was concluded that the filler cork helped to slightly improve the water resistance of the mixture. Although further investigation is needed, it can be stated that the filler cork could replace the conventional natural filler in the production of HMA.


41. PYROLYSED CORK WASTES USED FOR ULTRALIGHT-WEIGHT MICROWAVE ABSORBERS, EMI SHIELDING OR RAM MATERIALS Robert C. Pullar *, Rui M. Novais *, Ana. P. F. Caetano *, K. A. Krishnakumar † and Kuzhichalil P. Surendran

* Department of Engineering of Materials and Ceramics / CICECO – Aveiro Institute of Materials, University of Aveiro † Materials Science and Technology Division, CSIR-NIIST, Industrial Estate, Trivandrum

Keywords: Cork wastes; Microwave absorber; Amorphous graphite; Pyrolysed cork; Radar absorbing material RAM; X-band absorber; Specific Shielding effectiveness SSE Abstract. Cork is a renewable and sustainable material extracted from the outer bark of the cork oak tree, which only grows around the Mediterranean basin. It is a fully sustainable / renewable resource, as the bark is harvested every ~10 years, without harming the tree, which continues to live on as a carbon sink for a productive lifetime of at least 200 years. Indeed, a regularly harvested cork tree will absorb five-times more CO2 in its lifetime than one that is left alone. Portugal is the world’s largest cork producer, supplying ~50% of the global output, and processing 70%. Cork has a highly porous and lightweight structure, consisting of honeycomb-like ~20 μm hexagonal cells with 1 μm thick cell walls, and up to 200 million cells per cm3, which gives it a low density of 0.12 - 0.24 g cm-3. Cork powder is the main waste of the cork industry, generated throughout the fabrication stages of various cork products, estimated to reach around 50,000 t / yr. The most common use of cork is still as a stopper for wine bottles. One tonne of cork produces around 67,000 cork wine stoppers, 12 billion stoppers being produced annually worldwide, and although it is still early days for the recycling of these, there are already well established schemes that collect tens of thousands of tonnes of wine corks each year for recycling. We valorised waste cork powders and recycled wine cork stoppers to make pyrolysed/carbonised solid cork and powders, for use as microwave (MW) absorbers. There is a great deal of interest in materials which can absorb energy in the microwave to millimetre wave range (wavelengths of 1 m to 1 mm, frequencies of 300 MHz to 300 GHz). These have applications for EM shielding in devices and components, and electromagnetic interference (EMI) and electromagnetic compatibility (EMC) testing and standards measurements, as well as in security, communications blocking, stealth technology and radar absorbing materials (RAM) for military use. There are also increasing concerns about the possible 64

negative health implications of microwaves (MW) on the human body. In the case of stealth technology, RAM coatings on aircraft, naval vessels and missiles, and portable/wearable shielding, it is particularly important to employ lightweight materials. Of particular interest is the X-band, from 8-12 GHz, used for military radar and communications, some commercial and civil wireless and satellite communications, motion sensors and speed detection devices. To be useful, a reduction of at least -10 dB is needed. It is well known that carbon can be an effective MW absorber, suitable for EMI shielding and as radar absorbing materials (RAM) for stealth technologies, from the high MHz to millimetre wave frequencies. However, it is usually in the form of a polymer composite or carbon foam containing nanopowders, NPs, CNTs, graphene or carbon fibre, and has to be expensively processed f rom environmentally unsustainable precursors. Here we present the potential of pyrolysed/carbonised cork as an economic and sustainable microwave absorber over the X-band (8-12 GHz), used without a binder or additives. Even though the cork is already a very lightweight material (0.16 g cm-3), the pyrolysed cork is five-times less dense at 0.031 g cm-3. It was shown to be amorphous graphitic carbon. The pyrolysed cork has an excellent shielding effectiveness (SET) of -18 to -38 dB over the X-band, depending on thickness. Furthermore, this ultra-light-weight material has the greatest MW specific shielding effectiveness (SSE) ever reported, of between -640 to -1235 dB g-1 cm3 over the entire X-band range, depending on thickness (3.0-8.6 mm). This upper SSE value is more than twice that of any previously reported graphite-based foams, and for samples 3 mm thick the SSE is ~1.5 times greater than any carbon foam/CNT/NP mix or polymer/graphene foams, and 6 times greater than the best pure graphitic carbon foam over the X-band.


 † † † * M. PTAK , P. KACZYŃSKI , JOHANNES WILHELM , R.J. ALVES DE SOUSA *,1 AND F.A.O. FERNANDES * TEMA - Centre for Mechanical Technology and Automation, Universidade de Aveiro Campus Santiago, 3810-193, Aveiro, Portugal 1corresponding author:; Tel.: +351 234 378 176 † Wroclaw University of Science and Technology Faculty of Mechanical Engineering Łukasiewicza 7/9, 50-371 Wrocław

Keywords: cork, composites, graphene, mechanical tests, crashworthiness, energy-absorbing materials, natural materials Abstract. The use of cork for a variety of applications has been gaining significance due to environmental concerns and political agendas. Consequently, its range of applications is growing rapidly. In this work, aiming to improve its mechanical response for crashworthiness applications, cork agglomerates were enriched by small quantities of graphene oxide or graphene nanoplates in order to observe a resulting improvement of the mechanical behaviour during quasi-static and dynamic compressive loading cases. To produce homogenous cork agglomerates including graphene, the material was previously dispersed into granulated cork using stirrers to achieve a good distribution. Then, the typical procedure of compression and curing was carried out. Magnified images attest a good dispersion of graphene into the cork matrix. Mechanical testing was performed for a variety of graphene concentrations (0.1, 0.5 and 1.0 weight %), becoming clear that the beneficial effect of including graphene (either oxide or nanoplates) is related to a later densification stage while keeping the same stress plateau levels.


4.3. PRODUCTION OF CORK HOLLOW PIECES BY AN INNOVATE PROCESS BASED ON ROTATIONAL MOULDING * † †† Miguel Pestana , Manuela Mendes , Luís Miranda and António Corei Diogo ††† *Instituto Nacional de Investigação Agrária e Veterinária, I.P. (INIAV, I.P.) Unidade de Tecnologia e Inovação † Robcork, Valorização de Produtos de Cortiça, SA ††Rotomoldagem, SA †††Instituto Superior Técnico (IST) – Universidade de Lisboa

Keywords: Recycling, Rotational Moulding, Composite Materials, Cork, Polyethylene. Abstract. A new technique of producing hollow cork composite parts is presented. It is mainly based on rotational moulding of cork powder and thermoplastic materials. Cork powder is a by-product from cork industry which is potentially dangerous (risk of fire and explosion); the incorporation of cork powder into the new products constitutes both an application of increased added value and a safe utilisation of cork powders. A series of mechanical tests on samples extracted from rotational moulded parts of the new cork composite are presented. Compression tests, creep and creep recovery tests are reported. There is evidence of toughening and softening (increased creep compliance) as the cork content increases; in both cases, the macrostructure of the composite contributes to the overall changes.

1. INTRODUCTION Portugal is the biggest cork producer and exporter in the world (105 tonnes in 2010). It is estimated that cork waste (cork pellets and cork dust) from cork manufacture is about 20% to 30% of the raw material input [1]. The valorisation of such an amount is a big challenge and concern for cork industry. Cork agglomerates based on cork pellets found an increasing number of applications [2]. A number of prospective applications of cork pellets in different cork composites were also considered [3]. Valorisation of cork dust and cork pellets stands on looking for new applications with increased incorporation of added value. One example is project RotoCork (2011-15), which is a partnership among Robcork - Valorização de Produtos de Cortiça SA, Rotomoldagem SA, Instituto Nacional de Investigação Agrária e Veterinária, I.P. (INIAV, IP) and Instituto Superior Técnico - University of Lisbon (IST-UL), partially supported by Agencia de Inovação under COMPETE Program. The main goal of project RotoCork is the production of hollow pieces in cork 67

composites by non-standard variants of rotational moulding. Up to now, the standard way to produce hollow objects made of cork composites (e.g. cork agglomerate) was by excavating a massive solid block, previously obtained. This involves a protracted process which generates a huge amount of residues, which may attain 90% of the original weight. Manufacture of hollow parts in cork composites by non-standard variants of rotational moulding, with incorporation of cork dust and cork pellets, reduces the amount of secondary waste to some residual value which may be taken as negligible. Therefore, a direct outcome of RotoCork project is the upgrade of cork powder, a residue from cork industry, by its conversion to raw material for new products. Also, important savings in time and labour costs were accomplished. Two more accomplishments of the project must also be emphasized: first, a number of geometrical shape restrictions for hollow parts were removed, and second, the range of application of rotational moulding was extended to a new class of composite materials. A number of tests were performed in order to get a detailed characterisation of the new products: physico-chemical tests, mechanical tests and so on. The aim of this paper is to present the results of a number of mechanical tests involving creep under compression and creep recovery after compression. As a matter of fact, the performance of cork and cork composites is related to the way parts withstand compression stresses in different ways. A numerical simulation of the behaviour of cork agglomerates in compression and traction can be found in reference [4]. Creep tests were also considered. Creep tests very often cross the linear viscoelastic threshold. A discussion of non-linear creep effects e.g. in polyethylene (UHMWPE) can be found in reference [5]. 2. MATERIALS AND METHODS Several cork/polyethylene composite mouldings were produced by rotational moulding in different geometrical shapes, different formulations and different processing conditions. Tests were performed on rectangular plates extracted from the different parts. No shell testing will be reported here.

Figure 1 – Images of the rectangular plates cut from different mouldings. 68

For every moulding, at least three specimens were extracted. Some of them are shown in figure 1. In our nomenclature, PE refers to polyethylene, took as reference; A1, A2, A3 and A4 refer to PE + cork powder composites; A6, A7 and A10 refer to layered composites processed by sequential rotational moulding; A8 and A9 refer to PE and cork powder composites with high cork content. They were extracted from mouldings with different shapes, different compositions, and produced in different processing conditions. Compression testing, and creep and creep recovery testing were performed in an Amsler Otto Wolpert-Werke GMBH D-6700 press. Typical parameters used in compression tests were: initial force (-180 N), compression speed (-120 N/s), sampling time (2 s). The maximum force was either (-40 kN) or (-65 kN). Creep/ creep recovery tests, in compression, were performed by application of a trapezoidal force cycle to the specimens. In a trapezoidal compression cycle, a compression ramp force is applied at constant rate, up to a maximum chosen value (e.g. -40 kN). The maximum compression force is kept for a given time (holding time ~5 min) and then removed. After removal of the compression force the recovery of the initial shape is monitored. After recovery, a new cycle may be started. 3. RESULTS ANDA DISCUSSION In this section, the experimental results obtained in compression (uniaxial compression) and creep/creep recovery tests will be presented and discussed. Compression Stress-strain curves were computed from the force-displacement data collected in the experiments. For the strain ranges considered here, most of the strain values are well beyond the infinitesimal strain limit, so the Hencky strain {ln[l(t)/l(0)]} was adopted as the strain measure. We recall that one of the main advantages of the use of Hencky strain measure is additivity. Figure 2 displays the stress-strain curves for the specimens shown in figure 1. It is worth noting that the different stress-strain curves span a wide region of the stress-strain plane.


Figure 2 – Stress-strain curves of the cork-PE composites and of PE, in compression.

In figure 2 three different classes of behaviour emerge. The first one is constituted by low cork content HDPE/cork composites (A1, A2, A3 and A4), a second group is constituted by layered composites (A6, A7 and A10), and the third group includes samples A8 and A9 which are the ones with highest cork content. Average values of compression strength and compression modulus (Young modulus) for each class are presented in Table 1. Table 1 – Average values of compressive strength and Young modulus of the different classes of cork/HDPE composites.

Samples Compression Strength / MPa Young Modulus/ MPa



A3, A4


26.3±2.1 21.1±0.9





A8, A9



PE 30. 8 139 .3

Other important quantities are the changes of specimen thickness immediately after release of the compressive force, and after different times of recovery. The time of recovery is, by definition, the time lapse after compression release.


Table 2 – Deformation and recovery after one cycle compression test. A1, A2, A3, A4


A6, A7, A10

A8, A9


After test Hencky strain





Hencky strain after 
 50 min recovery





Recovery (Hencky)





There is a general pattern of increasing deformability (or increasing creep compliance) as the cork content increases. Also the recovery (after compression) shows a similar pattern. Creep Cork and thermoplastics are viscoelastic. Therefore, under a stress history s(t) which started t some finite time before the current time t, the time evolution of strain g(t) is t

γ (t) =


dσ(t ') dJ (t − t ') dt '.J(t − t '). = J g .σ(t) − dt '.σ(t '). d dt ' dt '




where J(t) is a material function, the creep compliance. The creep compliance is the sum of the instantaneous compliance Jg and the delayed compliance Jd(t):

J(t) = J g + J d (t)

(2) For a linear viscoelastic material with a single retardation time, l,

J d (t) = J d .(1 − e − t λ )


An example of a trapezoidal stress wave is shown in figure 3.








Figure 3 – Trapezoidal stress wave (compression).




The response of a linear viscoelastic material with a single retardation time, for which equation (3) holds, is given by equations (4-7). There is a direct correspondence between times t0…t3 in figure 1 and times t0…t3 in equations (4-7).


et λ − et0 λ 1 (t − t 0 ) .γ (t 0 < t < t1 ) = (J g + J d ). − J d .λ.e − t λ . σ0 (t1 − t 0 ) (t1 − t 0 )


e t1 λ − e t 0 λ 1 .γ (t1 < t < t 2 ) = (J g + J d )− J d .λ.e − t λ . σ0 (t1 − t 0 )

) (4)

) (5)



⎡ e t1 λ − e t 0 λ e t λ − e t 2 λ )⎤ ( 1 (t − t 3 ) −t λ ⎢ ⎥ .γ (t 2 < t < t 3 ) = − (J g + J d ). − J d .λ.e . − σ0 (t 3 − t 2 ) (t 3 − t 2 ) ⎥ ⎢⎣ (t1 − t 0 ) ⎦ (6)


) (

⎡ e t1 λ − e t 0 λ e t3 λ − e t 2 λ 1 −t λ .γ (t > t 3 ) = −J d .λ.e . ⎢ − σ0 (t 3 − t 2 ) ⎢⎣ (t1 − t 0 )

)⎤⎥ ⎥⎦


The generalisation of equations (4-7) to a discrete spectrum of retardation times is a bit cumbersome but can be done without major difficulty; it will not be presented here for the sake of space. This generalisation of equations (4-7) for a linear viscoelastic medium with a discrete spectrum of retardation times was used in the computation of the creep compliance. Figure 4 displays a typical response to a trapezoidal stress wave. Figure 5 displays the response to a sequence of trapezoidal stress waves. Hencky strain


Force strain 0,15



0 0





time/s Figure 4 – Response of one A7 specimen to a sequence of trapezoidal stress waves.


Figure 5 – Response of one A7 specimen to a sequence of trapezoidal stress waves.

In both cases a single retardation time is not enough to fit the time dependent creep compliance. Besides a short time process (of the order of a few seconds) which may be associated to wall bending, there is a long time process of the order of magnitude of an hour. The collapse of the cell walls introduces nonlinearity and some irreversibility in the viscoelastic response. A more detailed analysis will be presented elsewhere.

9. CONCLUSIONS Composites obtained from thermoplastics and cork powder may be processed by rotational moulding and they can provide hollow parts with minimum residues or by-products. This represents a substantial improvement when compared to the traditional way of excavating a massive solid block previously produced. Through the use of a number of improvements of basic rotational moulding technology, layered composites can also be produced. According to the composition and processing variables, it is possible to span a wide region of the stress-strain diagram for compression. As a matter of fact, the introduction of cork softens the thermoplastic: in more technical and precise words, cork incorporation increases the creep compliance of the composite. Modulation of the changes in creep compliance can be achieved by simultaneous changes in the cork content and in the processing procedures. Compression curves s Creep recovery depends on the amplitude of the compression force. At low amplitude values, linear behaviour is found. Linear (or quasi-linear) behaviour is recovered at high amplitudes, as a consequence of cork cells crushing; the retardation spectrum is nevertheless changed. At middle range amplitudes non-linear behaviour is found, much probably driven by cell walls buckling.


ACKNOWLEDGEMENTS Project RotoCork is funded by Agência de Inovação under contract QREN number 21542, in the framework of COMPETE Program and Sistema de Incentivos à Investigação e Desenvolvimento Tecnológico do QREN: financial support is gratefully acknowledged. REFERENCES [1] Cordeiro, N.; Belgacem, M.N.; Silvestre, A.J.D.; Neto, C.P.; Gandini, A. (1998). Cork suberin as a new source of chemicals. 1. Isolation and chemical characterization of its composition. International Journal of Biological Macromolecules 22, 71-80. [2] Pereira, H (2007). Cork: Biology, Production and Uses, Elsevier, Amsterdam. [3] Gil, L. (2009). Cork Composites: A Review. Materials, 2, 776-789. [4] Todo Bom, L.F.R. (2010). Comportamento à compressão e tracção da cortiça: estudo numérico. Dissertação de Mestrado em Engenharia Mecânica, Universidade de Aveiro. [5] André, J.R.S. e Cruz-Pinto, J.J.C. (2005). Previsão do comportamento à fluência do polietileno de massa molecular ultra-elevada. Revista Iberoamericana de Polímeros, 6, 181-198.


4.4. A NEW 3D PRINT FILAMENT BASED IN NATURAL BIOLOGICAL SOURCES AND CORK RESIDUES Flávia A. Vieira*†, Sara P. Magalhães da Silva*† and José M.M. de Oliveira*† * EMarT Group –Emerging Materials Research and Technologies ESAN School of Design, Management and Production Technologies †Aveiro Institute of Materials- CICECO. University of Aveiro

Keywords: bio-based composite, cork powder residues, 3D print technology, thermoplastic starch blends Abstract. Cork has attracted the curiosity of man since ancient times. Portugal has the largest cork oak (Querbus suber L.) forest in the world, occupying an area of ca. 737 million hectares [1]. The industry produces around 30% wt% of residues in powder form [2]. Recently, there is an increasing demand for natural and sustainable materials, which appeals to the natural use of cork. Cork has unique properties that should be explored in the development of filaments for additive manufacturing. The main goal of this work is to combine cork residues and maize starch thermoplastic to produce a cork polymer composite (CPC), 100% natural. Different formulations of thermoplastic based on maize starch, glycerol, water and citric acid were prepared and used as controls. In order to produce CPC, these thermoplastic starch (TPS) were mixed (by extrusion method) with different cork powders. Both (TPS and CPC formulations) were characterized in terms of their morphology (SEM analysis), thermal characteristics (DSC and Thermogravimetry analysis), and chemical properties (FT-IR). The TPS and CPC water absorption ability were evaluated during 16 weeks, regarding temperature and moisture exposure. All results were analysed under multivariate statistics. From this study, the best candidates to filament production were chosen and filaments were fabricated. REFERENCES 1.

K. S., Oliveira, V. Machado, J.S., H. Pereira. Cork as a Building Material: A review. European Journal of Wood

Production. (2016) 74:775–791; 2. A. Matos, S. Nunes, J. Sousa-Coutinho, Cork waste in cement base materials. Materials and Design (2015) 85:230–239. [3]F. Versínio. O. Lopez, M.A. Garcia, N. E. Zaritzy, Starch- based Films and Food Coatings: An overview. Starch. 2016) 68: 1.12


 * * * Rui M. Novais , Luciano Senff▲, João Carvalheiras , Maria P. Seabra , Robert C. * * Pullar and João A. Labrincha * Department of Engineering of Materials and Ceramics / CICECO – Aveiro Institute of Materials University of Aveiro ▲ Department of Mobility Engineering Federal University of Santa Catarina (UFSC)

Keywords: Inorganic polymer, cork, lightweight aggregate, thermal conductivity Abstract. Buildings energy consumption represents around 40% of the total energy consumption in EU [1], being also responsible for 36% of the CO2 emissions. In this context, the use of lightweight and low thermal conductivity materials may be an efficient way to decrease the energy losses inside buildings and increase their energy efficiency level. Geopolymer foams have attracted a huge amount of interest due to the possibility of being produced at room temperature by using a simple, low cost and green technology, but also to their high thermal stability and non-flammable character. In this work, and for the first time, cork was used as a lightweight aggregate to produce ultralightweight (260 kg/m3) and low thermal conductivity (72 mW/m K) geopolymer composites.

REFERENCES [1] R. M. Novais, G. Ascensão, M. P. Seabra, J. A. Labrincha, “Lightweight dense/ porous PCM-ceramic tiles for indoor temperature control” Energy and Buildings, vol. 108, pp. 205-214, 2015.


 # # * *1 M. Ptak , J. Wilhelm , F.A.o. Fernandes and R.J. Alves de Sousa # Wroclaw University of Science and Technology Faculty of Mechanical Engineering * Center for Mechanical Technology and Automation Universidade de Aveiro

Keywords: traffic safety, agglomerated cork, carbon fiber, natural composites, energy absorption, crashworthiness, bumper Abstract. The aim of the research was to improve the safety of the vulnerable road users through the development and implementation of a frontal protection system (FPS), which mitigates the injuries during an accident with a vehicle. Due to the trend for the purchase of SUVs in Europe and their more frequent participation in accidents involving pedestrians and cyclists (cars are used in cities) the authors identified a great need for a safe frontal protection system. The FPS provides pedestrians and cyclists with appropriate, supported by numerical tests, kinematics after collision with the vehicle, while at the same time contributing to the reduction of injuries through the use of appropriate energy-consuming materials, i.e. natural energy-absorbing materials (cork) and composites (carbon fibre). As a part of the research, multivariate numerical models and a physical prototype were created. This implementation of the combination of cork with carbon fibres allowed the authors to substitute steel and aluminium alloys in the FPS. It should be emphasized that the developed of the new FPS not only enhanced the VRU safety but also improved the design of the vehicle front-end.


 # # # * *,1 J. Wilhelm , P. Kaczyński , M. Ptak , F.A.o. Fernandes , R.J. Alves de Sousa 
 # Wroclaw University of Science and Technology Faculty of Mechanical Engineering * Center for Mechanical Technology and Automation Universidade de Aveiro

Keywords: agglomerated cork, natural composites, extreme high and low temperatures, high-energy impacts, crashworthiness Abstract. Cork material is utilized nowadays in a wide variety of applications due to its excellent shock absorption, thermal and acoustic insulation properties. Especially, this applies to agglomerated cork, which is acting in applications of even highly demanded dimensional stability nearly isotropic due to the random orientation of its grains and offers dominantly viscoelastic behaviour with almost zero Poisson’s ratio. As the interest in the outdoor application of cork material increases, the assessment of its performance under extremely low and high temperatures is inevitable. The research addresses this topic for five different types of cork agglomerates and assesses their capability to withstand an impact energy of 500 J from sub-zero temperatures of -30ºC up to 100ºC. Thereby, the research covers a full span of working circumstances, including automotive and aeronautics and their passive safety applications. The results show dependent on the tested temperature significant variations in the amount of absorbed energy. Hence, the attention of product designers and developers is called to consider the temperature-dependent performance, when it comes to dimensioning of product for extreme weather conditions.


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