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From Forests to Heritage: book of abstracts

Session 1: Built heritage

S1-O-001

Dendrochronological research in Amsterdam monuments. Timber trade, construction and methodological implications

Gabri van Tussenbroek1, 2

1 City of Amsterdam, Monuments & Archaeology. 2 University of Amsterdam, Faculty of Humanities, Department of Art History, the Netherlands.

Since 2006, dendrochronological research of buildings is being carried out in the historical inner city of Amsterdam. The aim is to obtain knowledge about the dating of structures; to increase knowledge about the use of wood, its origin and the wood market in the past.

In my contribution, after a brief general overview of the collected data set, I would like to focus on three sub-topics.

1. The transition from oak to pine for construction timber around 1600. It will be highlighted that this led to new solutions in construction. Moreover, it will be shown that the regular 'ordinary' house construction shows an essentially different pattern of wood use than buildings commissioned by the city authorities.

2. The availability of wood on the local market and the turnover rate of wood between the time of felling and the time of construction. The re-use of wood will also be considered here: this was more common at a time of shortage, linked to the major building campaigns that accompanied the urban expansions of the seventeenth century.

3. The methodological implications of this research. The question to be addressed is the extent to which dendrochronological research provides new knowledge about the building history of the entire city. The significance and quality of this material source will be compared to written sources, showing that dendrochronological research can lead to new interpretations of archival material.

S1-O-002

Convex shaped church tiebeams from the 11th - 13th century in the Diocese of Lund compared with European examples

Karl-Magnus Melin1, Petter Jansson2, Johannes Edvardsson3, Anton Hansson3, Hans Linderson3, Heikki Ranta4

1 Conservation, University of Gothenburg, Gothenburg, Sweden. 2 Regional Museum, Kristianstad, Sweden. 3 Department of Geology, University of Lund, Lund, Sweden. 3 Diocese of Lund, Swedish church, Lund, Sweden.

Tie beams from about 25 churches in the Diocese of Lund (part of Denmark until 1658) have been dated and examined with craft research methods. In total 16 of these churches the tie beams have also been analysed dendrochronologically. The oldest are from 1060s and the youngest from the 1250s. Common features are sharp edges, rectangular cross sections and generally convex shaped beams (thickest in the middle and thinner at the ends). In this paper these attributes will be discussed and compared with tie beams from Sweden, France, Belgium and England. Were similar wood quality used in the or are there regional and or differences over time? The convex shape will be discussed, why was it a common way to make tie beams and why did it suddenly not be important? Convex shaped tie beams are dated to the period 1060-12 th century. The oldest dated example of parallell-sided tie beams is from 1185 in Norra Åsum chancel. Why did the tradition of convexshaped tie beams end? Was it a change of building fashion /construction or was material quality a reason? A sampling protocol made by craft researchers and dendrochronologists used for this investigation will also be described. In some of the churches radicarbon dating of the mortar were performed close to the dendro-sampled tie beams. The different dating methods will be discussed. The transdisciplinary research methods have been vital for this investigation.

S1-O-003

Unveiling the innovation behind the roof constructions of the Medieval Churches in Finland

Liisa Seppänen1, Panu Savolainen2, Laura Laine2

1 Department of Archaeology, University of Helsinki, Finland. 2 Architectural History Research Group, Department of Architecture, Aalto University, Helsinki, Finland.

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In northern Europe, all construction, including monumental and sacral architecture, was based solely on the use of timber until the 11th century, and remained dominant until the 19th century. The construction techniques included log frames and various post and stave techniques, where the stave churches of Norway represent the globally most widely known part of this heritage.

In eastern part of the Kingdom of Sweden, nowadays Finland, log construction had dominated architecture since the prehistorical era and remained the most important construction technique in all buildings apart from castles until the early 15th century.

The beginning of the 15th century with the erection of numerous stone and brick churches brought along new challenges in covering larger spans than ever before. The roof trusses of Lohja church from the late 15th century are among the largest in Europe covering a span of 20 meters. The origins of the innovations were in the 12th century northern France from where the techniques were adopted to the Baltic region and eventually applied to wooden roof constructions in Finland.

Our paper presents new evidence and research of these roof trusses in the North-Eastern fringe of Medieval Europe. We examine the differences and similarities of medieval roof constructions in Finland and compare them with evidence from other parts of northern Europe. Furthermore, we explore the heritage aspects related to wooden architecture, church attics and roof trusses in Finland.

The research has been performed in an on-going project “Structural innovations in late Middle Ages in northern Europe”.

S1-O-004

Lonely Brussels. Destination: the old built heritage and its woods

Paulo Charruadas1, Sarah Cremer2, Patrick Hoffummer3, Sylvianne Modrie4, Philippe Sosnowska1, 3, Armelle Weitz2

1 Université libre de Bruxelles, Brussels, Belgium. 2 Royal Institute for Cultural Heritage (KIK-IRPA), Brussels, Belgium. 3 Université de Liège, Liège, Belgium. 4 Service public régional Bruxelles Urbanisme et Patrimoine - urban.brussels, Brussels, Belgium.

For the past 30 years, the timber used in the building sector of Brussels has been under the microscope of archaeologists, historians and dendrochronologists with a sharp increase in studies over the past ten years.

From the foundations to the frameworks, via the shutters and floors, the buildings of Brussels-Capital Region are beginning to give us their own stories about the management of the exploitation of the forest and the supply of building sites. The various investigations show that Brussels frequently had to deal with problems of timber supply. This has led to a strong pressure on the local resources and forced the construction sector to use the entire local forest resource for timber but also to import wood products.

Regarding the methodology, the structure studied in Brussels benefit from an archaeological recording. Archaeological research is conducted (typology of frameworks, metal assemblies and traces of woodworking) as well as dendrochronological dating, wood species analysis and – when possible - archival research.

We would like to outline some of the general characteristics of the the use of wood in Brussels, from the management of timber resources (forest trees and hedge trees) to the choice of species used in relation to the built structures (roof frames, floor frames, flooring). This approach will be put into perspective with certain political events that have punctuated the city's history. Particular attention will be given to the crossing of archaeological, dendrochronological and historical data.

S1-O-005

The use and results of dendrochronological research in building history research in Leiden (the Netherlands)

Edwin Orsel1

1 Erfgoed Leiden en Omstreken, Leiden, the Netherlands.

The wood used in built heritage is an unprecedented physical source for research into the history of building. Since 2001, dendrochronological research has been applied in structural building-historical research in Leiden (NL). The research area concerns a local context of one historic city centre with buildings from approximately 1200 to the present. Initially, the dendrochronological research was carried out by external parties, but since 2014 the building historians of Erfgoed Leiden have been taking the samples themselves. The independent sampling during building-historical fieldwork is very practical and efficient. Until 2021, more than 150 objects have been dendrochronologically examined. Sampling limitations sometimes pose problems in dendrochronological analysis, especially in the older coarser wood, and therefore a study was conducted using a combination of dendrochronology and C14, with positive results.

The results of dendrochronological research in Leiden provide insight into the dating of the buildings, the origin of the construction timber, transport and trade and other aspects. The dates range from the beginning of the 14th century to the end of the 18th century. It has become clear that first oak wood imported from Germany was used, but that later the oak came from further away. Around 1600 the transition from oak to pine is unmistakable, supplied from areas around the Baltic Sea. Exact dates also provide insight into which season was felled and also in the period between logging and fabrication. In this way, dendrochronological research contributes substantially to the knowledge about our past.

S1-PR-001

A 2ka-long tree-ring chronology for hinoki cypress from central Japan and its dendroarchaeological application

Motonari Ohyama1, Hitoshi Yonenobu2, Shinya Suzuki3, Yasuharu Hoshino4

1 Botanical Gardens, Tohoku University, Sendai, Japan. 2 Graduate School of Education, Naruto University of Education, Naruto, Japan. 3 Tokyo Metropolitan Archaeological Center, Tokyo, Japan. 4 Center for Archaeological Operations, Nara National Research Institute for Cultural Properties, Nara, Japan.

We present a 2ka-long ring-width chronology of hinoki cypress and its application for wooden cultural properties. Hinoki cypress is dendrochronologically the most critical species in Japan because it has been extensively used for important cultural properties. We collected samples from old-growth living and buried trees as well as from wooden cultural properties located at temples and archaeological sites in central Japan. They built up a ring-width chronology for each site, and these chronologies were then successfully crossdated to compose a single 2ka-long chronology for the period of 156 BCE to 2001 CE. Because ring-width chronologies of cypress from central Japan are known to be crossdatable with others from large adjacent areas of the country, the new data will be useful in building chronologies for other parts of Japan. Using this chronology, we also present dating results of timbers from a building of Chiko-ji temple in central Japan, which was built in the late 13th and/or early 14th century.

S1-PR-002

Protective symbols applied by craftsmen on worked timber during the 16th and 17th centuries, and some reasons for their application

Timothy Easton

Timber components in houses from the southern part of Britain are frequently found to have had distinctive marks scribed on their visible surfaces by carpenters. During the last 50 years, the author has been collating these symbols to show how the simplest forms from the early 16th century developed into more complex arrangements towards the later 17th century. By careful analysis he has shown when the earliest were added to chimney beams and this has led him to speculate the reasons that they were required to be put within most homes. Although his study is mainly from South East England, the symbols collected from English ecclesiastical buildings and furnishings show their early origins from the first half of the 16th century. These furnishings with protective marks are not just from England but are also seen also on North European furniture.

S1-PR-003

Roof constructions in Austria – an overview

Sebastian Nemestothy1, Elisabeth Wächter1, Günther Buchinger2, Michael Grabner1

1 Institute of Wood Technology and Renewable Materials, University of Natural Resources and Life Sciences, Vienna, Austria. 2 Denkmalforscher GesBR, Vienna, Austria.

The tree ring lab at BOKU University, Vienna, Austria is active since 1996 in the eastern part of Austria (Salzburg, Carinthia, Styria, Upper and Lower Austria, Vienna and Burgenland). Up to now more than 22,000 samples were taken from buildings.

Parallel to the dendro-dating, building historians have been analysing the typology of roof trusses and the changes with time. It was possible to see clear alterations from simple rafter- constructions, to huge multi-level constructions with standing and sometimes hanging columns, to the ship-like baroque trusses and once again to constructions with standing columns.

The existing tree-ring-database makes it possible to present new insights on the historical roof trusses. At 982 buildings roof constructions were sampled and analysed – ending with 13,916 samples. The time span reaches from the oldest roof truss at the church in Salzburg dated to 1135, to the youngest one in Vienna dated to 1997.

69.0% of the sampled elements were made out of Norway spruce followed by Silver fir with 19.6%. All other species played a minor role: pine (5.0%), larch (3.6%), oak (2.7%), followed by few elements made out of Stone pine, elm, beech and poplar. The share of wood species represents clearly the huge influence of the alpine region. Within the city of Vienna, where all building material was rafted, the amount of spruce wood is 72.3%. There were no clearly visible changes in the share of wood species over time.

The wood species composition in Austria is different to other regions, where often oak is dominating; or tremendous changes in the share can be seen.

S1-P-001

Oak dating in Lithuania

Adomas Vitas1

1 Environmental Research Centre, Faculty of Natural Sciences, Vytautas Magnus University, Kaunas, Lithuania.

Oak timber in Lithuania was used in building constructions in Klaipėda oldtown and Vilnius Lower castle. The constructed oak chronologies for Klaipėda and Vilnius spans from the 13th to 16th centuries. However, it is not possible to identify the origins of the samples collected during the 1980s in Klaipėda because a book with records from this stage of the investigation was lost. In addition, oak is present in the standing buildings of the central part of Lithuania. Because of favourable soil conditions, to date, oak is more prevalent in the forests of central Lithuania than in other regions. In 2018–2019, oak timbers from altarpieces and construction elements of seven churches in central Lithuania were studied. In total, fifty-three oak samples were sampled, and 40 tree-ring series were dated. Although the timber from the 18th to 19th centuries predominates, the oldest samples were dated to 1526 and 1635. The samples from the 16th to 17th centuries were dated against Klaipėda and chronologies constructed from oak timber imported from Baltic lands to western Europe, such as Baltic1 and Baltic3. Finally, the newest material was dated using chronologies constructed from living oaks in Lithuania. As a result, the compiled oak chronology for Lithuania spans from 1659 to 2005.

S1-P-002

The oldest known roof construction in Ghent (Belgium) sheds new light on medieval building history

Vincent Debonne1, Kristof Haneca1

1 Flanders Heritage Agency, Brussels, Belgium.

Roof constructions are considered key elements to document and study building traditions in historic towns. As a material source, the wood used in roof constructions allows to precisely date the timing and duration of building activity by means of tree-ring dating.

In Flanders (northern Belgium) precise tree-ring dating is often hampered by the type of wood used (fast growth rate, short tree-ring series) and the intensive fashioning of the timbers (waney edge removed/trimmed). The latter implies that only an interval for the felling date can be settled.

In the city centre of Ghent, numerous roof constructions from the pre-industrial era are still in place, in large monuments (churches, city hall, merchants’ halls) but also in historic houses. Tree-ring research on these has been carried out since the 1990s (Université de Liège; Van Daalen Dendrochronologie; Flanders Heritage Agency). The dated roofs range from the middle of the 13th century to the early 16th century.

We here present an overview of all dendrochronologically analysed roof constructions in Ghent and add new data from an iconic monument: Saint-Nicolas’ church. The roof of the nave now proves to be the oldest preserved in the city and wider region, with a felling date for the timbers between 1220 and 1224 CE. The roof above the choir was erected a decade later, with a felling date for the timbers between 1231 and 1240 CE.

These new results and the wider dataset for the Ghent region now allow to develop a typology for (late)medieval roof constructions and a better understanding of the procurement, trade and transport of building timber, from the early 13th century up to the beginning of the Early Modern era.

S1-P-003

Utilization of wood species in timber constructions across the Czech lands from the 15th to the 19th century

Tomáš Kolář1, 2, Petr Dobrovolný2, 3, Péter Szabó4, Tomáš Mikita5, Tomáš Kyncl6, Josef Kyncl6, Irena Sochová1, 2, Micha Rybníček1, 2

1 Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czech Republic. 2 Global Change Research Institute of the Czech Academy of Sciences (CzechGlobe), Brno, Czech Republic. 3 Department of Geography, Faculty of Science, Masaryk University, Brno, Czech Republic. 4 Department of Vegetation Ecology, Institute of Botany of the Czech Academy of Sciences, Brno, Czech Republic. 5 Department of Forest Management and Applied Geoinformatics, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czech Republic. 6 DendroLab Brno, Brno, Czech Republic.

Wood represents fundamental material for buildings either as part of houses made of bricks and/or stone or as a whole house (e.g. log houses). Utilization of individual species for buildings could substantially change in space and time due to regional availability of the species. In this study, we present 8135 dendrochronologically exactly dated timber constructions, represented mainly by roofs and ceilings, across the Czech Lands in order to investigate variations in wood species selection between the 15th and the 19th century. Our results show that availability of individual species, wood properties, and stem geometry played a key role for the utilization wood species in historical timber constructions. Vast majority of historical constructions (99.7%) were made of fir, spruce, pine, and oak. Timber constructions in eastern part of the Czech Republic are mostly made of fir, whereas in central and western part of spruce. Pine and oak constructions are typical of specific regions, which reflects natural occurrence of the species at lower elevated central Bohemia and southern Moravia. Representation of individual wood species changed in time especially due to planting of spruce monocultures starting in the 19th century. Whereas fir prevailed in timber construction until the end of the 18th century, spruce utilization started to increase significantly at the end of the 19th century. Our study shows that dendrochronological datasets may be used to investigate wood utilization in the past.

Acknowledgments: This work was supported by the SustES – Adaptation strategies for sustainable ecosystem services and food security under adverse environmental conditions project, ref. CZ.02.1.01/0.0/0.0/16_019/0000797, and by long-term research development project no. RVO 67985939.

S1-P-004

The use of dendrochronology to understand aspects of sustainability in traditional wooden houses

Linda Lindblad1

1 The Craft Laboratory, Department of Conservation, Faculty of Science, University of Gothenburg, Mariestad, Sweden.

This paper will present and discuss the possibilities of craft research and dendrochronology to understand and describe how traditional wooden architecture in Sweden can contribute to more sustainable housing. The traditional use of timber will be examined in log timber living houses that are more than 150 years old and still in use. Methods to map the properties of the wood material in-situ will be defined and tested in an initial workshop, where invited experts present different methods and their application. Then the examinations of four or five log timber living houses will be performed by craft researchers and dendrochronologists with the interdisciplinary approach from craft science and kulturvård.

In the examinations we will investigate; what kind of timber these buildings were built with, how the wood has been used, modified, sourced and processed. Also, the quantity of wood in the construction is estimated. Signs of repairs will be documented since it illustrates how the building technique enables repair and circular material use.

Dendrochronological analyses will then be used as a tool to further understand the properties of the timber, felling season, tree ring widths and which type of forests the trees once grew in, the felling years will be of minor importance. Together craft researchers and dendrochronologists will try to solve the main and important questions: How can wooden living houses last for several hundred years? Can we by understanding the timber quality, used techniques and historic forestry today and in the future build longlasting sustainable wooden houses?

S1-P-005

Methodological approach of wood anatomy and dendrochronology in cultural heritage

Maks Merela1, Katarina Čufar1, Luka Krže1, Angela Balzano1, Andrej Gaspari2

1University of Ljubljana, Biotechnical Faculty, Department of Wood Science and Technology, Ljubljana, Slovenia. 2University of Ljubljana, Faculty of Arts, Department of Archaeology, Ljubljana, Slovenia

We intend to present some methodological approaches for the application of wood anatomy and dendrochronology to various cultural heritage objects. An appropriate combination of microscopic techniques allows the detection of anatomical features for wood identification, while another combination of microscopic techniques may be optimal to determine the state of preservation of the wood at the cellular level. The latter is particularly important in the study of archaeological waterlogged wood, where assessing the degree of cell wall degradation determines the research potential of the wood and the conservation of particular objects. We will present the results of light microscopy (different light modes), epifluorescence, confocal laser scanning microscopy, digital microscopy, and scanning electron microscopy on various cultural heritage objects. We will discuss when wood is considered sufficiently preserved for tree-ring analysis and show examples of dendrochronological studies on various cultural heritage objects as well as on waterlogged objects.

Finally, we will address the need for ongoing maintenance of reference chronologies, which must be available for different wood species and time periods, as well as the optimal selection of wood for radiocarbon dating and wiggle matching when dendrochronological dating is unsuccessful or not possible.

The right choice of methods (conventional and modern) allows us to extract a long list of information from the wood of cultural heritage objects.

S1-P-006

Dendrochronological dating of historical sacral constructions in Transcarpathian Ukraine

Irena Sochová1, 2, Tomáš Kolář1, 2, Michal Rybníček1, 2

1 Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czech Republic. 2 Global Change Research Institute of the Czech Academy of Sciences, Brno, Czech Republic.

Wooden churches are an important part of cultural heritage and have a very long history in the most western part of Ukraine, currently called Transcarpathian Ukraine. Hundreds of wooden churches, chapels or belfries, likely built between the 15th and 19th century, have been preserved in this area. However, construction history of the buildings remains unclear as dates presented in literature are usually inaccurate and contradictory. Therefore, the main aim of this research is to determine the age of preferably oak historical constructions, as well as compile a historical part of oak tree-ring width (TRW) chronology.

In this study, totally 158 oak samples from 12 oak churches and belfries from 4 districts (Mukachevo, Tiachiv, Vynohradiv and Chust) of Transcarpathian Ukraine have been collected and processed using standard dendrochronological methods. Study includes the measured TRW series of 5 churches transported in 1919–1938 from the area of Subcarpathian Ukraine to the Czech Republic

So far 60 TRW series has been dated mostly using Romania (Maramures) and Slovakia TRW chronologies to the 17th and 18th centuries. All well cross-dated TRW series have been used to compile a basis of historical oak TRW chronology for Transcarpathian Ukraine which covers the period 1400–1820. All TRW series will be used to compile the historical part of the standard TRW oak chronology, which will complement the previously compiled recent chronology for the Transcarpathian Ukraine region. This will help with further dendroarcheological studies as well as dendroclimatological studies.

Acknowledgements: The paper was prepared with the funding from the Internal Grant Agency FFWT MENDELU, grants numbered LDF_VP_2020010, LDF_VP_2021008 and IGA-LDF-22-IP-004.