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Some of the oak planks unearthed in the foundations of the portico. These planks are an example of those used for building Rome.      Source: Soprintendenza Speciale Archeologia, Belle Arti e Paesaggio di Roma, Italy

Imported Timber is the Newly Discovered Secret to Building Rome

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An analysis of some 2000-year-old planks of wood has provided amazing insights into the Roman Empire . Experts have been able to establish that timber found in the heart of Ancient Rome was imported from abroad. This discovery is helping researchers to understand the building of Rome and the sophistication of its trading networks.

During work on a subway project, workmen found 24 muddy oak planks, which dated back to the Roman period.  They were part of the foundations of a portico of a large villa. This was owned by a patrician family and was richly decorated. PLOS ONE reports that the villa was “near the Basilica of San Giovanni in Laterano, just outside the ancient Aurelian walls.”

Map of the excavation site in Rome, between the Aurelian walls (black line) and Rome’s Metro line C, near the Basilica of San Giovanni in Laterano (M Bernabei , J Bontadi, R Rea, U Büntgen & W Tegel / PLOS ONE )

A Very Rare Find

Now planks may not sound very exciting, but they were in an excellent state of preservation. A number of experts including Mauro Bernabei, a dendrochronologist from the Italian National Research Council, knew that the planks were an unusual find. There is very little dendrochronological evidence from the city because of the hot environment. Bernabi told a Press Release that “the area where the samples were found was completely submerged by the wet mud of the Tiber River.” This meant that the planks had been preserved because they were immersed in waterlogged earth for centuries, which protected them from harmful fungi.

Oak planks unearthed in the foundations, showing their preservation ( Bernabei at al., 2019 / PLOS ONE )

The team first began to study the growth rings in the wood, which show a tree's growth over time. Cross-sections of the plank were cut using a scalpel and white chalk was used to highlight the rings. The widths of the tree-rings were measured using a highly accurate specialist device, called a LINTAB device.

Planks from France

It was found that four of the planks were hewn from trees that were over 250 years old when they were felled by loggers. The growth rings not only dated the trees, it also allowed researchers to “pinpoint where wood comes from by looking for trees with matching growth ring patterns” according to Inside Science . Specialists measured the width of rings of the individual planks, and these were compared with data from growth rings from other oak trees in Europe.

Initially they were compared with Italian tree-rings but no correlations were found. The researchers established that the best match for the planks was with oaks from the Jura Mountains, in south-east France, which in the Roman period was in the Province of Gaul.  This means that the planks came from trees that were over 1000 miles (1700 km) from Rome. Further tests on their sapwood established that the planks came from trees cut down between 40 and 60 AD.

More of the planks unearthed at the excavation site (M Bernabei, J Bontadi, R Rea, U Büntgen & W Tegel / PLOS ONE)

More of the planks unearthed at the excavation site (M Bernabei, J Bontadi, R Rea, U Büntgen & W Tegel / PLOS ONE )

Rome’s Logistic Machine

The length of the planks and their distance from Rome means that they were transported by professional traders. Based on the geography of the Jura region, it is likely that they were floated down the “principal waterways of the province of Gaul, the Saône and Rhône rivers” reports PLOS ONE . They were probably taken by ship to the port of Ostia, and from there to Rome. They would have been regarded as high-quality construction materials and would have been much sought-after.

The discovery of foreign wood demonstrates the sophistication of the trading networks used in building Rome. It also shows that Romans had the ability to move even heavy and bulky items, like these 12-foot (4m) long planks, a great distance. Inside Science quotes Bernabi as stating that the muddy planks reveal the “huge, impressive logistic machine” controlled by the Romans.

Map of Roman provinces in today’s France and Germany, with Roman’s probable logistics network used for building Rome (M Bernabei , J Bontadi, R Rea, U Büntgen & W Tegel / PLOS ONE)

Map of Roman provinces in today’s France and Germany, with Roman’s probable logistics network used for building Rome (M Bernabei , J Bontadi, R Rea, U Büntgen & W Tegel / PLOS ONE )

New View on Building Rome

The unearthing of foreign wood in the heart of Rome should not be a surprise. It appears that the Romans had stripped the Apennine Mountains of timber that was suitable for construction. It also showed that they depended on foreign supplies for this critical material used for building Rome. According to PLOS ONE “wood was important for any aspect of everyday life, ranging from the construction of buildings to heating systems, and from shipbuilding to metalworking”. The Romans used timber to build their majestic city and also their vast empire.

This research is something of a first, and it could provide a new view of the timber found on Roman archaeological sites. Much of the materials may be of foreign origin and not just the valuable woods, such as ebony and cedar, which were highly prized in patrician houses. Many of the planks found in other archaeological sites, such as Pompeii, were probably imported. The experts have shown how valuable oak was as a construction material and have identified a long-distance timber trade route, which linked the forests of Central Europe and Rome. The full results of the study are being published in the online journal PLOS ONE.

Top image: Some of the oak planks unearthed in the foundations of the portico. These planks are an example of those used for building Rome.      Source: Soprintendenza Speciale Archeologia , Belle Arti e Paesaggio di Roma, Italy

By Ed Whelan

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