From forests to early medieval fortress: Dendroarchaeological discoveries at the 10th-century Menka Hillfort, Belarus

The hillfort on the Menka River marks the beginning of the history of Minsk (formerly Mensk), the capital of Belarus, although its exact date of origin had long remained unknown. During the 2023–2024 archaeological excavations, the ramparts surrounding the hillfort were investigated, and at their base, a massive wooden structure was uncovered. This structure, built primarily from oak ( Quercus sp.) and consisting of a continuous row of double square log frames, represents the original defensive wall that enclosed the Menka Hillfort in the 10th–11th centuries. Dendrochronological analysis was conducted on 96 oak wood samples, of which 45 were successfully cross-dated. These samples enabled the construction of an early medieval oak tree-ring chronology MNK01 spanning 170 years. This chronology was absolutely dated by comparison with subfossil oak chronologies from neighbouring regions and covers the period from 828 to 997 AD. The trees used in the structure were felled between the second half of 997 and early spring of 998 AD. A moving rBar analysis revealed a prolonged period of reduced growth synchrony among the trees, lasting from approximately 910 to the 980 s AD. The presence of asynchronous abrupt growth changes and wounds occurring in different trees at various times within this interval suggests the impact of human activity on the forest. These patterns may indicate that settlement on the Menka River began to develop in the first decade of the 10th century.