Archaeology Roman expansion left its mark on the forest
The Romans massively changed the forests north of the Alps. This is shown by an international research team in a new study for which they analyzed pieces of wood dating back to 300 BC.
25.11.2025, 09:09
25.11.2025, 09:10
SDA
During their reign, the Romans heavily cleared the forests, as the researchers showed in the study published on Monday evening in the journal "Proceedings" of the US Academy of Sciences ("Pnas").
The study is based on a collection of over 20,000 pieces of wood whose age was determined using their growth rings. They date from the period between 300 BC and 700 AD. The pieces of wood were found during archaeological excavations in areas that were occupied by the Romans at the time, including parts of France, Germany and Switzerland.
The analysis showed that the need for wood for the construction of houses, roads, bridges, military installations and ships increased as the empire expanded. As a result, the Romans pushed further and further into untouched forests to meet their growing demand for resources.
Forests became younger
At the beginning of the Roman occupation, the forests were still rich in old trees. Over time, however, the average age of the trees declined and older stands were increasingly replaced by younger, faster-growing trees.
Particularly old forests with tree populations of at least 200 years were heavily used and overexploited, especially in the 3rd century AD. This century is regarded as a turning point in the study: there was a significant decline in the use of wood and the supra-regional transportation of timber.
Recovery until the Middle Ages
In the centuries that followed, particularly in the 4th and 5th centuries, deforestation continued to slow down. After the end of Roman rule, the forests were increasingly able to recover and old forest stands spread again - a process that can be traced back to the early Middle Ages.
According to the researchers, the study shows for the first time with high temporal resolution how closely Roman expansion was linked to profound ecological changes. The authors emphasize that their findings provide crucial insights into the long-term interplay between human activity and forest ecosystems.
From Switzerland, the archaeology offices of the cantons of Thurgau, Chur, Bern, Zurich and Neuchâtel were involved in the study, as well as the University of Geneva and other specialized dendrochronological agencies such as the Competence Centre for Underwater Archaeology and Dendrochronology in Zurich.
