PICEA SCHRENKIANA RING WIDTH AND DENSITY AT THE UPPER AND LOWER TREE LIMITS IN THE TIEN SHAN MTS (KYRGYZ REPUBLIC) AS A SOURCE OF PALEOCLIMATIC INFORMATION

Abstract

We present here the results of spruce (Picea schrenkiana Fish. et May.) tree-ring research in the Tien Shan Mountains, Kirgiz Republic. We explore the connection between climatic parameters and spruce ring width and maximum density at the upper and lower tree limits and provide two reconstructions: the May-August temperature reconstruction from 1626 to 1995 based on a multi-site composite maximum density chronology from the upper tree limit and the drought index reconstruction from 1680 to 2000 based on the lower tree limit regional ring width chronology. The ring width chronologies from the upper and lower tree limits show a strong similarity. They both depend to a large extent on moisture availability. The maximum density chronology does not correlate with them: it depends on different climatic parameters, namely on the summer temperature. The correlations of the reconstructions with CRU TS3 temperature and precipitation grid point data confirm the results of the modeling using the meteorological data from the nearest stations. The 20th century does not look unusual in the context of the last three hundred years in the Tien Shan Mountains, either in terms of the drought occurrence and severity or in summer temperature changes. However the reconstruction does not encompass the last decade when the summer warming in Tine Shan has been especially prominent. In contrast, some change in precipitation is indicated with the 19th century being drier in the Issyk Kul region compared to the 20th century.