Western Lesbos contains fossil trunks, roots, leaves, seeds and branches from a subtropical forest buried by volcanic material roughly 20 million years ago. Silica-rich fluids gradually replaced organic tissues while preserving microscopic structure and growth patterns. The result is not a collection of carved stones but geological evidence for plants, climate and explosive volcanism in the early Miocene Aegean.
The protected natural monument is distributed across a broad landscape rather than contained in one fenced grove. It forms a defining part of the UNESCO Global Geopark of Lesvos. Standing fossil trunks with root systems preserved in growth position are especially valuable because they record an ecosystem where it lived, while transported trunks document eruption and water processes.