Mapping “tree root damage risk” for the conservation of archaeological sites: the case of the Domus Aurea (Rome)

Damage caused by tree root growth to archaeological monuments buried underground over the course of centuries, has been frequently reported in the city of Rome. The Domus Aurea, Nero’s Imperial residence, now lies under the Horti Traianei on the Oppian hill. These gardens, planted at the beginning of the last century, are located only 3-4m above the surviving archaeological structures. In some cases roots have damaged the vaults, sometimes creating serious structural problems. Results of the study show that a variety of species have a strong root system growing for many meters laterally, and to depths of several meters, and identification of the plants responsible for the damage has been done through study of their wood anatomy. A real and potential assessment of the risk tree roots pose to the archaeological structures has been attempted. The data collected will contribute to evaluating the risk to monuments under similar conditions and will also help to avoid errors made in managing the plant cover of archaeological sites