The ups and downs of the building trade in a medieval city: Tree-ring data as proxies for economic, social and demographic dynamics in Bruges (c. 1200-1500)

The exceptional preservation of the cityscape in the medieval city of Bruges (Belgium) triggered dendrochronological research on numerous preserved roof constructions in historical buildings, that date from the Middle Ages up to the early modern period. As many of these oak timbers lack the preservation of waney edge, a method was developed to combine sapwood estimates of felling dates within each building phase and to compute a summed probability distribution (SPD) for those felling dates. These summed probabilities now allow us to reconstruct temporal trends in building trade activity in an expanding medieval city. When linked to the social status of the patrons of the building projects, it is observed that resilience to demographic crisis and political turmoil differs among the social groups and political elite of a medieval society. Furthermore the dating results of decades of tree-ring research now provide a typo-chronological framework of roof constructions and shows that it took nearly two centuries before more advanced technological skill in the construction of roofs completely replaced the traditional common rafter roofs.