What does the wood hide?

Dating and provenancing is generally achieved by applying classical dendroprovenancing, based on ring-width analyses. The spatial precision of provenancing provided by annual variation in ring-width patterns can potentially be further enhanced by including additional information stored in the anatomy of the wood. The field of quantitative wood anatomy has strongly developed in the last years due to the improvement of measurement equipment, which allows measuring wood-anatomical features with high precision and efficiency. Wood-anatomical features hold information on site-specific, mainly climate forced, growing conditions, with the potential of being valuable indicators for provenancing.

During the Age of Discovery and European Expansion (16th to 18th centuries), ocean-going ships became paramount to the development and sustainability of Iberian empires. The construction of ships placed unprecedented demands on Iberian forests, leading to forest management practices and enactment of laws to ensure timber supply for shipbuilding.

Oak and pine were the preferred species for structural timbers of ships, hence they can be found nowadays in shipwrecks from Spanish and Portuguese ships in different parts of the world . However, the identification of those ships by name and nationality is problematic if not impossible, as the establishment of their exact place and time of construction remains a challenge for historians, nautical archaeologists and dendrochronologists.

The interdisciplinary Marie Curie ITN ForSEAdiscovery project combines disciplines from the Humanities (historiography and nautical archaeology) and the Life Sciences (dendrochronology, wood anatomy, and geo/dendro-chemistry) to address the broad question of the timber supply for Iberian Empires in the Age of Discovery (16th to 18th century). A specific question for the Life Sciences group is the development of methods for provenancing oak and pine ship timbers derived from trees grown in the Iberian Peninsula. Establishing the Iberian origin of timbers retrieved from shipwrecks would inform about the extent of the timber provision from specific Iberian forests during the 16th to the 18th century, and the changes in forest structure and management as a consequence of exploitation and further degradation. In this manner, wood recovered from shipwrecks represents a natural archive to reconstruct forest history and ancient management practices.

At present, provenancing Iberian ship timber is hampered by the lack of reference datasets for the peninsula (e.g., a wide-coverage tree-ring data network spanning more than 500 years). The development of identification keys based on genetic and wood-anatomical features (i.e. independent from ring-width datasets) to identify oak and pine timber as “Iberian”, would be a major contribution to the much needed reference data network. For this, I study wood-anatomical characteristics determined by i) genetics of the species, ii) local/regional growing conditions (forest ecology and regional climate), and iii) forest structure and ancient forest management practices, which result in specific timber qualities. We anticipate that the methods developed could be employed to provenance timber elsewhere.