Temperature variations recorded in Pinus tabulaeformis tree rings from the southern and northern slopes of the central Qinling Mountains, central China

The Qinling Mountain range constitutes a critical boundary for climate and vegetation distribution in eastern central mainland China owing to its importance as a geographic demarcation line. In this article, cores from 88 Chinese pines (Pinus tabulaeformis) from the southern (MW site) and northern (NWT site) slopes of the Qinling Mountains were used to reconstruct seasonal temperature variations. During the calibration period, significant correlations were found between ring width and the mean temperature from prior September to current April of 0.76 at the southern slope, and between ring width and the mean May-July temperature of 0.67 at the northern slope. The subsequent temperature reconstructions span 1760-2005 for the northern site and 1837-2006 for the southern site. Prior to the mid-20th century, low September-April temperatures were, in general, followed by high May-July temperatures, probably reflecting variations in the winter and summer monsoon. However, since the mid-20th century, both records show trends of a more pronounced increase in September-April temperature on the southern slope. The results provide independent support for the interpretation that recent warming is unusual in nature, coinciding with the observed record. The results compare well with tree-ring based reconstructions from the surrounding regions, suggesting regional signals in the Qinling Mountain reconstructions.