Response Characteristics of Chinese Pine (Pinus tabulaeformis Carr.) Radial Growth to Climate and Drought Variability Reconstruction in Western Liaoning, Northeast China

Chinese pine (Pinus tabulaeformis Carr.) plays an important role in maintaining ecosystem health and stability in western Liaoning Province and the southern Horqin sand land, Northeast China, with benefits including sand fixation and soil erosion. In the context of climate change, developing a better understanding of the relationship between climate factors and growth rates of this species will be extremely valuable in guiding management activities and meeting regional conservation objectives. Here, the results based on two groups of tree-ring samples show that the radial growth of Chinese pine is controlled primarily by water conditions. The longer chronology had the highest correlation coefficient with the January-September mean self-calibrating Palmer Drought Severity Index (scPDSI); therefore, drought variability was reconstructed for the period 1859-2014. Statistical analysis showed that our model explained 41.9% of the variance in radial growth during the 1951-2014 calibration period. Extreme dry and wet events, defined as the criteria of one standard deviation less or greater than the mean value, accounted for 19.9% and 18.6% of the 156-year climate record, respectively. During the past century, the regional hydroclimate experienced significant long-term fluctuations. The dry periods occurred from the early-1900s-1930s and 1980s-2000s, and the wet periods occurred from the 1940s-1970s. The drought reconstruction was consistent with the decreasing trend of the East Asian summer monsoon since the late 1970s. The reconstructed temporal patterns in hydroclimate in western Liaoning were closely related to the large-scale climate drivers in the North Pacific and the tropical equatorial Pacific. The teleconnections were confirmed by spatial correlations between the reconstructed sequence and sea surface temperature (SST) in the North Pacific, as well as the correlations with the Pacific Decadal Oscillation (PDO) and El Nino Southern Oscillation (ENSO) indices. Aerosols played an important role in affecting drought variations over the past several decades. Moisture stress caused by global warming and interdecadal changes in the PDO will have long-term effects on the growth of pines in the study area in the future