Reconstructing past climate variability on Holy Mount Athos, Greece using monastic archives and dendrochronology

The archives of Holy Mount Athos, Greece, an UNESCO World Heritage Site, constitute an invaluable treasure trove of Byzantine and post-Byzantine documents and manuscripts that offer unique evidence for reconstructing past climate, resulting from the long-term human presence in the area through monasticism. This study combines references to climatic events from the archives of the Holy Monastery of Vatopedi with the study of annual growth rings using the dendrochronology method on samples of Aleppo pine, with the aim of identifying and cross-validating historical climate extremes.Research in the Historical Archive of the Holy Monastery of Vatopedi focused on extreme phenomena, searching manuscripts mainly for keywords such as floods, frost, storms, famine, and periods of drought, yielding references stretching back several years. To this end, approximately 150 letters from monks in the wider Vatopedi area were studied and 28 references to climatic events were recorded, focusing on the mid-18th to the mid-19th century. At the same time, samples were collected from 20 different trees in three clusters of Aleppo pine within the forest area of the Holy Monastery of Vatopedi using Haglöf Sweden increment borer. The implementation of a Lignostation system for high-resolution ring-width and density measurements resulted in ring timeseries associated with extreme precipitation and ambient temperature in the region’s climate.The initial samples processed reveal significant correlations between years with “narrow rings” and recorded episodes of drought or flooding, reinforcing the reliability of both types of data. These findings reconstruct climate extremes on Mount Athos before the era of measuring instruments, providing baseline data for assessing long-term variability and informing contemporary climate change adaptation strategies in Mediterranean landscapes.