Understanding the Timber Needs of the Romans During the Time of Jesus

Due to the Empire’s vast extent and long endurance, Rome had a profound and lasting influence on the development of art and science.  Its later adoption of Christianity led to the formation of Christendom during the Middle Ages.   I love the intersection of Christianity and wood and Rome’s architectural tradition served as the basis for Neoclassical architecture.  The basis of this blog is the journal article, “Dendrochronological evidence for long-distance timber trading in the Roman Empire” by Mauro Bernabei, et al. which was published on December 4, 2019 in the open journal PLOS ONE. 

The Bible has an interesting relationship with trees and wood.  In Matthew 21:18-22, Jesus curses the fig tree that has no fruit.  In Exodus, 25-31 and 35-40 we learn how acacia wood was used to construct the Tabernacle and the Arc of the Covenant.  In secular literature, there has been unproven speculation that the dogwood tree was used as the cross to crucify Jesus and the small, white, cross-shaped flower is a possible reminder.

In Rome, timber requirements were immense [5,3]. The demand for timber led to the rapid depletion of the woodlands surrounding the capital and in much of the Apennines. As the Empire expanded, timber cutting continued abroad: in Pliny’s time (1st century CE), some of Algeria’s forests rich in sandarac trees (Tetraclinis articulata), a wood particularly appreciated by the Romans, had already been fully exploited so that its timber supply shifted to Morocco [1]. And Emperor Hadrian created an imperial forest, by fencing off the cedar of Lebanon woodland and marking its perimeter with inscribed boundary stones, in order to conserve those woods [6].

At the same time, recent advances in dendrochronology have made important contributions to archaeological research [10]. Given the right conditions, wood can be dendrochronologically dated to the calendar year [11,12]. Moreover, tree-ring research can determine the wood’s provenance [13], and sometimes it may even help to identify political and economic networks of commercial trade [14]. Unfortunately, in the Mediterranean region, the necessary conditions for dendrochronological analysis are rarely given [15,16]. Wood is preserved over a long period of time only in very humid or very dry locations, at very low temperatures, in contact with metal or in the form of charcoal [7,17]. In Mediterranean archaeological excavations, pottery and iron, for example, are easily found but wood is rare, and often it only occurs as minute fragments bonded to metal [18].

Due to the scarcity of datable wood, only a few and so far unpublished multi-millennial reference chronologies exist for Italy. This circumstance effectively hampers the dendrochronological assessment of Roman timbers. Hence, most studies on Roman timber constructions refer to archaeological sites outside of Italy concerning, for instance, the dating of ships [19,20,21,22], barrels [23] and the reconstruction of trade routes [24,25].

This study is, therefore, the rare exception of a successful dendrochronological investigation of archaeological timbers in the city of Rome, which has allowed us to: a) date these timbers by the method of dendrochronological cross-dating, b) determine the timbers’ geographical origin (provenance), and c) compare the dendrochronological results with those derived from historical and archaeological sources (multi-proxy comparison).

The timber requirements of ancient Rome were immense and complex, with different types of trees from various locations around the Roman Empire and beyond used for many purposes, including construction, shipbuilding and firewood. Unfortunately, the timber trade in ancient Rome is poorly understood, as little wood has been found in a state adequate for analysis. In this study, Bernabei et al successfully date and determine the origin and chronology of unusually well-preserved ancient Roman timber samples.

The twenty-four oak timber planks (Quercus species) analyzed in this study were excavated during Metro construction in Rome during 2014-2016. They formed part of a Roman portico in the gardens of via Sannio (belonging to what was once a lavishly decorated and rich property). The authors measured the tree-ring widths for each plank and ran statistical tests to determine average chronology, successfully dating thirteen of the planks.

By comparing their dated planks to Mediterranean and central European oak reference chronologies, the authors found that the oaks used for the Roman portico planks were taken from the Jura mountains in eastern France, over 1700km away. Based on the sapwood present in 8 of the thirteen samples, the authors were able to narrow the date these oaks were felled to between 40 and 60 CE and determined that the planks all came from neighboring trees. Given the timber’s dimensions and the vast distance it travelled, the authors suggest that ancient Romans (or their traders) likely floated the timber down the Saône and Rhône rivers in present-day France before transporting it over the Mediterranean Sea and then up the river Tiber to Rome, though this cannot be confirmed.

The authors note that the difficulty of obtaining these planks—which were not specially sourced for an aesthetic function but used in the portico’s foundations—suggests that the logistical organization of ancient Rome was considerable, and that their trade network was highly advanced.

Bernabei notes: “This study shows that in Roman times, wood from the near-natural woodlands of north-eastern France was used for construction purposes in the centre of Rome. Considering the distance, calculated to be over 1700km, the timber sizes, [and] the means of transportation with all the possible obstacles along the way, our research emphasises the importance of wood for the Romans and the powerful logistic organisation of the Roman society.”

Credit:  Mauro Bernabei, M., J. Bontadi, R. Rea, U. Büntgen, and W. Tegel.  Dec. 4, 2019. Dendrochronological evidence for long-distance timber trading in the Roman Empire.  PLOS ONE.  https://doi.org/10.1371/journal.pone.0224077

Todd Shupe is the President of Wood Science Consulting, LLC. He is a a well-recognized expert on wood preservation, insects and fungi, wood decay and degradation, and wood species identification. He has a broad background in new product development, quality management, and marketing and sales in both the public and private sectors. For more information please visit DrToddShupe.com.