Tree rings as biosensor to detect leakage of subsurface fossil CO2.

Highlights: [•] Most subsurface CO₂ monitoring lacks long-term data. [•] Tree rings records from Caldera Latera (Italy) provide biomonitoring data. [•] We use ¹⁴C concentration in tree rings to detect CO₂ outgassing. [•] Natural permanent CO₂ leakage does not influence oak growth patterns. [•] Decadal variations in caldera CO₂ outgassing rate are demonstrated. [Copyright &y& Elsevier]