Reconstructed May-July mean maximum temperature since 1745Â AD based on tree-ring width of Pinus tabulaeformis in Qianshan Mountain, China

A tree-ring-width chronology of Pinus tabulaeformis was developed from the Qianshan Mountain, Liaoning province, northeastern China. Based on the correlation between the ring width and instrumental data, a transfer function was designed and the May-July mean maximum temperature (MMT) from 1745 to 2012 was reconstructed. The reconstruction explains 42.7% of the instrumental variance during the calibration period (41.7% after adjusting for the loss of the degrees of freedom). The reconstructed MMT is similar to several observed MMT series and the temperature index in north-central China, which indicated that the decrease in summer temperatures in the 20th century was a large scale phenomenon. The reconstruction also showed that high MMT values corresponded to historical drought events in Liaoning. In addition, a spatial correlation analyses revealed that the MMT reconstruction is regionally representative. Significant 128.2-, 64.1-, 18.6-, 3.46-, 3.19-, 2.43-, 2.15- and 2.10-year cycles were detected in the reconstructed MMT series from Qianshan Mountain.