Series Chronology, Culture and Archaeology (CCA) reports; 4. University College Dublin. School of Archaeology.

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1 Provided by the author(s) and University College Dublin Library in accordance with publisher policies. Please cite the published version when available. Title Dendrochronological analysis of oak from a shipwreck, Rostock Ost FPL71, Germany Author(s) Daly, Aoife Publication Date Series Chronology, Culture and Archaeology (CCA) reports; 4 Publisher University College Dublin. School of Archaeology This item's record/more information Downloaded T11:17:05Z Some rights reserved. For more information, please see the item record link above.

2 CCA Report 4 September 2011 Dendrochronological analysis of oak from a shipwreck, Rostock Ost FPL71, Germany Chronology, Culture and Archaeology

3 CCA report 4 (September 2011) Dendrochronological analysis of oak from a shipwreck, Rostock Ost FPL71, Germany Aoife Daly, Ph.D. Marie Curie funded project: Chronology, Culture and Archaeology, based at the School of Archaeology, University College Dublin. The main theme of the project is the analysis of short tree-ring sequences but other themes are also addressed, namely maritime timber, digital data sharing and non-destructive analysis. The analysis described in this report is within the maritime timber theme, and is in collaboration with Jens-Peter Schmidt, Landesamt für Kultur und Denkmalpflege Mecklenburg- Vorpommern and Mike Belasus, Deutsches Schiffahrtsmuseum, Bremerhaven. In this report the dendrochronological analysis of eight oak samples from a shipwreck found at Rostock Ost is described. In the interest of access to data and to enable researchers to utilise this material in the future, all measurements are submitted to the Digital Collaboratory for Cultural Dendrochronology (DCCD, The eight samples come from different constructional components of the ship. All samples are dated (see fig. 1). Ship s planks Five samples are from planks from the ship, but none of these have sapwood preserved. The tree-ring curves from two planks (3 & 7) are so similar that they might come from one tree, and these two are averaged and treated as one tree in the further analysis. As a group, and allowing for missing sapwood, the felling date for the trees that were used to make the ship s planks is estimated at after AD Rostock Ost FPL71, dendrochronological dates frame 8 Z AD Z077002a AD sp mitte Z077001a after AD 1294 plank 90 Z077008a after AD Z after AD Z077005a after AD Z077006a after AD Z077004a after AD Fig. 1. Rostock Ost FPL71. Diagram showing the chronological position of the dated samples from the shipwreck.

4 Z077M005 Z077008a Z Z077006a Z077004a Z077005a Z077001a Z Z077002a CCA report 4 September 2011 Ship s frames Three samples are taken from the ship s framing timbers. Sapwood is preserved on two of these. The felling date for the trees that the two frames that have sapwood preserved come from is estimated to AD and AD respectively. The third frame, that has only heartwood preserved, is from a tree that was felled after AD The latter frame might represent repair to the ship. A number of estimates for the average number of sapwood years in oaks in Northern Europe have been calculated, and in northern Germany, oak trees have an average of 20 sapwood years (±10) (Hollstein 1980).It is this sapwood statistic that is used here. Provenance The correlation (t-value) between the dated tree-ring curves from ship FPL71 from Rostock Ost is shown in table 1. It can be seen that a very high t-value is achieved between two of the ship s planks (samples Z077006a (3) and Z077004a (7)), and visual inspection of the graph plot of the tree-ring widths from these two allows the possibility that these two are from the same tree. Z077002a * 3, Z ,35 * 4,27-4,76 4, Z077001a - 4,27 * 3,49 4,58 3, Z077005a - - 3,49 * 4,17 4,76 - \ Same tree Z077004a - 4,76 4,58 4,17 * 12,24 - \ Z077006a - 4,55 3,83 4,76 12,24 * 3,15 3,17 Z ,15 * 7,38 Z077008a \ \ 3,17 7,38 * Table 1. Rostock Ost wreck. Correlation between the tree-ring curves from the ship s timbers. A mean curve Z077M005 has been made, covering 233 years, from AD 1053 to In table 2 the correlation between this mean and diverse oak site and master chronologies for Northern Europe is shown. The timbers match best with timbers from sites on the Southern Baltic coast around Lübeck and Szczecin. The ship was built of timbers that probably grew in this broad region. 2

5 Analysis For measuring and for the analysis and the calculation of the t- value ( t-test ), DENDRO (Tyers, 1997) and CROS (Baillie & Pilcher, 1973) are used. In the analysis master and site chronologies for Northern Europe are employed. Filenames - - Z077M005 - start dates AD dates end AD1285 DM AD1023 AD1723 8,02 Lübeck (Hamburg University) P727001M AD952 AD1272 7,69 Szczecin (Wazny pers comm.) DM AD436 AD1968 7,32 Schleswig-Holstein (Hamburg University) Z056m001 AD1065 AD1266 7,27 Egelskärsvraket Finland barrel (N German provenance) (Daly 2011) S AD1067 AD1305 6,77 Kolobrzeg (Wazny pers comm.) G351WZ01 AD1084 AD1354 6,46 Suderburg (Göttingen University) H11JPM01 AD946 AD1241 6,38 HL Fischstr. 36 (Hamburg University) G311IZ01 AD1060 AD1193 6,33 Bodenwerder (Göttingen University) F004M001 AD1132 AD1263 6,28 Viborg Skt Pederstræde barrel (N German provenance) (Daly 2007) H11JAM01 AD1118 AD1278 6,09 HL Mengstr.40. (Hamburg University) P671001M AD980 AD1347 6,05 Elblag (Wazny pers comm.) DM AD914 AD1873 5,77 Lüneburger Heide (Göttingen University) SM AD855 AD1385 5,74 Mid Sweden (Lund University) DM AD915 AD1873 5,52 Niedersachsen Nord (Göttingen University) 4M AD1058 AD1350 5,43 Danmark Svendborg (Bartholin pers comm.) PM AD725 AD1985 5,24 Gdansk (Wazny pers comm.) ZEALAND0 AD452 AD1770 5,16 Zealand (Daly upubl.) H11JBM01 AD1138 AD1290 5,15 HL Koenigstr.16 (Hamburg University) DM BC AD1960 5,10 Weser (Göttingen University) Table 2. The results of the calculation of correlation between the chronology for shipwreck FPL 71 and diverse site and master chronologies from Northern Europe. The source of the chronologies is given. The grey tone highlights the high t-values. Literature Baillie, M.G.L. and Pilcher, J.R., 1973: A simple crossdating program for tree-ring research. Tree-Ring Bulletin 33, Daly, A., Timber, Trade and Tree-rings. A dendrochronological analysis of structural oak timber in Northern Europe, c. AD 1000 to c. AD Ph.D. thesis submitted February 2007, University of Southern Denmark. Daly, A., Egelskärsvraket Finland. dendro.dk rapport nr : 2 Hollstein, E Mitteleuropäische Eichenchronologie. Trierer Grabungen und Forschungen 11. Mainz am Rhein. Tyers, I.G., Dendro for Windows Program Guide, ARCUS Report 340, Sheffield. 3

6 Catalogue Catalogue format: Filename Title and sample number Tree species (QUSP = Quercus sp., oak, PISY = Pinus sp., pine, PCAB = Picea abies, spruce) and number of years measured Chronological position of the tree-ring curve Number of sapwood years, presence of bark Felling date Z077001a FPL71 Rostock Ost spant mitte Raw Ring-width QUSP data of 159 years length Dated AD 1124 to AD 1282 Average ring width Sensitivity 0.20 Interpretation after AD 1294 Z077002a FPL71 Rostock Ost spant nord 3 von mitte Raw Ring-width QUSP data of 173 years length Dated AD 1113 to AD sapwood rings and no bark surface Average ring width Sensitivity 0.18 Interpretation AD Z FPL71 Rostock Ost spant fdnr 8 Raw Ring-width QUSP data of 231 years length Dated AD 1053 to AD sapwood rings and no bark surface Average ring width Sensitivity 0.16 Interpretation AD Z077004a FPL71 Rostock Ost plank fdnr 7 Raw Ring-width QUSP data of 76 years length Dated AD 1154 to AD 1229 Average ring width Sensitivity 0.16 Interpretation after AD 1240 Z077005a FPL71 Rostock Ost plank fdnr 34 Raw Ring-width QUSP data of 48 years length Dated AD 1155 to AD 1202 Average ring width Sensitivity 0.16 Interpretation after AD 1213 Z077006a FPL71 Rostock Ost plank fdnr 3 Raw Ring-width QUSP data of 82 years length Dated AD 1148 to AD 1229 Average ring width Sensitivity 0.17 Interpretation after AD

7 Z FPL71 Rostock Ost plank fdnr 97 Raw Ring-width QUSP data of 55 years length Dated AD 1134 to AD 1188 Average ring width Sensitivity 0.19 Interpretation after AD 1199 Z077008a FPL71 Rostock Ost plank fdnr 90 Raw Ring-width QUSP data of 47 years length Dated AD 1135 to AD 1181 Average ring width Sensitivity 0.18 Interpretation after AD 1192 Filename sample title and number rings start yr. End yr. Conversion pith sapwood bark? group extra start extra end interpretation / felling Z077001a FPL71 Rostock Ost spant mitte QUSP O C H2 after AD 1294 Z077002a FPL71 Rostock Ost spant nord 3 von mitte QUSP O C S1 AD Z FPL71 Rostock Ost spant fdnr 8 QUSP O C AD Z077004a FPL71 Rostock Ost plank fdnr 7 QUSP T G H1 after AD 1240 Z077005a FPL71 Rostock Ost plank fdnr 34 QUSP T G H1 after AD 1213 Z077006a FPL71 Rostock Ost plank fdnr 3 QUSP T G H1 after AD 1240 Z FPL71 Rostock Ost plank fdnr 97 QUSP T G H1 after AD 1199 Z077008a FPL71 Rostock Ost plank fdnr 90 QUSP T G H1 after AD 1192 Z FPL71 Rostock Ost planks 4+6 same tree QUSP after AD 1240 Z077M005 FPL71 Rostock Ost 7 timber mean QUSP Conversion: R = radial split plank, T = tangential plank, W = whole timber, S = squared whole timber, H = half timber, Q = quarter timber, O = other conversion. Pith: C = centre, V = less than 5 rings, F = 5 10 rings, G = greater than 10 rings. Aoife Daly, ph.d. 26 th September

8 Chronology, Culture and Archaeology (CCA). Funded through a Marie Curie Intra-European Fellowship (IEF) and based at the School of Archaeology, University College Dublin, the project is concerned with the precise dating of timber and wood from archaeological or historical contexts. As dating results emerge these are disseminated to project collaborators through this CCA report series. Full publication of the extensive material and methodological advancements will be prepared during the course of the project and submitted to peer review journals. 6