Forest history, timber supply and tree rings

Abstract

This thesis is devoted to review, assess and validate the potential of dendroarchaeology in the Iberian Peninsula, to define strategies for its future development and implementation in this territory, and to illustrate the importance of its application in the study of cultural heritage made of wood. To accomplish these main goals, a review of the current state of dendroarchaeology in the Iberian Peninsula was carried out, together with four pilot projects directed at exploring every aspect covered by dendroarchaeological research. One of these projects consisted on the development of multi-century reference chronologies of black pine (Pin us nigra subsp. saizmannii) at different elevations in the Cazorla and Segura mountains (eastern Andalusia), to explore their suitability as dating and provenancing tools for historic timbers. The other pilot projects illustrate the application of dendroarchaeology to provide, in addition to absolute dates, information about the provenance of the wood, the organisation of timber supply, the transport and trade of timber, and the evolution of wood-working techniques during the Early Modern Period. For this, dendroarchaeological research was carried out on historic buildings (Jaen Cathedral and Colegial dei Salvador church in Seville), selected art-historic objects (Evangelistas altarpiece at Seville cathedral) and shipwrecks (Arade 1 shipwreck, found at the mouth of the Arade river in the south of Portugal, excavated, and later on conserved at the Centro Nacional de Arqueología Náutica e Subaquática, in Lisbon). The results have demonstrated that dendroarchaeological studies have a great potential in the Iberian Peninsula. Wood from historic buildings, art-historic objects and archaeological contexts is abundant in the territory and represents an historic, ethnographical and environmental archive that can be studied by means of dendrochronology. This thesis shows that to achieve a well replicated set of reference chronologies needed for dating cultural heritage from this geographical region, strategies for tree-ring data compilation should be directed at key source areas along elevation, latitudinal and longitudinal gradients, covering all possible environmental niches. To improve the replication of the earlier centuries of those chronologies and extend them back in time, timbers from historic buildings offer the best prospects, although the selection of buildings should be preceded by documentary research, in order to acquire as much information a priori as possible in what regards the origin of the wood. The transport and trade of timber within the peninsula, and specially the import of raw timber and manufactured timber products into Spain and Portugal are questions that can be addressed by dendroarchaeology, as demonstrated in this thesis. They also provide a broader, international dimension to future research lines. Dendroprovenancing studies have a paramount role in this territory, hence multidisciplinary national and international collaboration is required to explore novel, high-resolution approaches to establish the provenance of historic wood. Last but not least, campaigns of awareness about the potential of this discipline to increase our understanding of cultural heritage have proven effective in the short and medium term, but for dendroarchaeology to be fully established in Spain and Portugal, structural support and commitment from national and regional institutes, research centres and academic institutions is essential. Only then will dendroarchaology reach the full potential and high quality standards that have already been acquired in most of northern, central and eastern Europe.