The Study Of Dendroclimatology In The Middle And Eastern Of Boertala Mongolia Autonomous Prefecture, Xinjiang Province

According to the Setsurei spruce tree ring samples collected from nine sites inthe middle and eastern of Boertala Mongolia Autonomous Prefecture, in2010, usingthe method of spline function, the tree-ring width chronologies were developed. Theresults indicated that XHZ chronology close to the lower limit of the forest and JPKchronology nearby the forest ceiling contains Climate information more than othersby the comparison and analysis some parameter of tree ring chronology. Correlationanalysis showed that, From July last year to June of that year’s XHZ chronology andprecipitation were significantly correlated (r=0.599, p<0.000001), while there waspositive correlation between the JPK chronology and the annual mean minimumtemperature(r=0.586, p<0.000001). Taking into account of precipitation andtemperature will have lag effect to tree-ring, By stepwise regression method,Reconstructed of the long-term precipitation series from July last year to June of thatyear, In the same way, the long-term average annual minimum temperature sequencewas reconstructed. It is confirmed that the reconstructed precipitation and temperaturesequence is reliable.389years precipitation and517years annual mean minimumtemperature series were well reconstructed. Analysis of redevelopment sequenceshows:(1) The growth of the Setsurei spruce in the middle and eastern of BoertalaMongolia Autonomous Prefecture presence of impact from its limited precipitation(from July last year to June of that year), and the lowest temperature (from Decemberlast year to November of that year). Results have obvious physiological significance.Reconstruction equation is stable by cross testing.(2) Seven drought period and seven wet period existed in389years. Theminimum precipitation stage in1815-1849,6.8percent below the long-term average;maximum precipitation stage in1739-1764, above the long-term average of7.1%.The longest drying phase last35years in1703to1738, the longest rainy stage tookplace from1850to1900, to continue for50years.Seven cold period and seven warm period existed in517years. The Warmeststage occurred from1843to1907,0.23°C above the long-term average, coldestphase in1707to1728,0.25°C below the long-term average; from1843to1907, forthe longest periods of warmer temperature, continued for65years, from1764to1842,for the longest colder stage, continued for79years. (3) Precipitation mutation (from July last year to June of that year) occurred in1740,1808years. High to low in1808and low to high in1740.Temperature mutation (from December last year to November of that year)occurred in1568,1667,1708,1734and1845years. Sudden changes from high to lowin1568and1708, and from low to high to sudden changes in1667,1734and1845.Significant period of change2.11a,2.05a and2.03a at the0.05level in thelong-term precipitation reconstruction sequence;3a,3.8a,5a for the averageminimum temperature.