Temperature Signals in Tree-Ring Width Chronologies of Alpine Treeline Conifers from the Baishui River Nature Reserve, China


Numerous dendro-climatic reconstructions have been developed for China, but there are still regions with limited data of this type. One region is the Qinling Mountains which is characterized by complex interactions between the mountains and climate. Presently, the subalpine region of the Qinling Mountains is covered by widespread forests and has great potential for dendroclimatological studies. Here we developed tree-ring width chronologies from two fir (Abies faxoniana) and one spruce (Picea brachytyla) sites in the Baishui River Nature Reserve, the western region of the Qinling Mountains, China. Climate response analysis reveals that radial growth of the fir site (TLD) is mainly controlled by temperature variations. The TLD chronology accounts for 32.7% of February - June temperature variance during the period 1959 - 2006. Using a linear regression approach, we reconstructed the February - June temperature of Wen County for the past 252 years. The cool periods are identified for AD 1795 - 1800, 1812 - 1827, 1881 - 1888, 1895 - 1902, 1916 - 1929, 1967 - 1972 and 1978 - 1995. Warm conditions prevailed during AD 1783 - 1794, 1801 - 1811, 1828 - 1856, 1867 - 1880, 1889 - 1894, 1903 - 1915 and 1930 - 1966. Wavelet analysis reveals the existence of some cycles (2.0 - 3.4, 5.7, 10.0 and 19.3 years). Spatial correlation analysis shows that the temperature reconstruction captures regional climatic variations over Central and Southwest China. The moving t-test indicated an abrupt warming change of our reconstruction occurred during the past 20 years. Overall, our study indicates the feasibility of combining tree-rings and the temperature to reconstruct large-scale temperature patterns over this area.

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