Degraded temperature sensitivity of a stone pine chronology explained by dendrochemical evidences

Fluctuations in sulphur (S) content in tree rings were analysed for a 93 years long period (1915–2007) by laser ablation system coupled to an inductively coupled plasma mass spectrometer from three Swiss stone pine (Pinus cembra L.) trees grown in the Rachitis Cirque, Calimani Mts, Eastern Carpathians. Investigated domain envelops the period of degraded climatic sensitivity of pines’ growth. Chemical data were standardized for sapwood and heartwood separately. The averaged sulphur record calculated from the three individual records unequivocally presents anomalously high S content for the tree rings dated to 1970s and 1980s. Ring-width fluctuation portrays changes of summer temperature but from 1966 to 1986 pines produced apparently larger rings than the corresponding summer temperatures can explain. This deviating interval coincides with the period of exploitation in the nearby sulphur mine. The elevated S content in tree rings refers probably to the dispersion of S-rich dust around the mine owing to the opencast type of exploitation. The divergent growth trend and degraded climatic signal likely due to the anthropogenic altered nutritional status of the site, as residues from nitrogen fertilizer, applied as a compound of explosive in the opencast sulphur exploitation, could be deposited on the surrounding forest.