Tree-ring response of Larix chinensis on regional climate and sea-surface temperature variations in alpine timberline in the Qinling Mountains

Tree-ring width chronologies of Larix chinensis were developed from the northern and southern slopes of the Qinling Mountains in Shaanxi Province,and climatic factors affecting the tree-ring widths of L.chinensis were examined.Correlation analysis showed that similar correlations between tree-ring width chronologies and climatic factors demonstrated that radial growth responded to climate change on both slopes.The radial growth of L.chinensis was mainly limited by temperature,especially the growing season.In contrast,both chronologies were negatively correlated with precipitation in May of the previous year and April of the current year.Spatial climate-correlation analyses with gridded land-surface climate data revealed that our tree-ring width chronologies contained a strong regional temperature signal over much of northcentral and eastern China.Spatial correlation with seasurface temperature fields highlights the influence of the Pacific Ocean,Indian Ocean,and North Atlantic Ocean.Wavelet coherence analysis indicated the existence of some decadal and interannual cycles in the two tree-ring width chronologies.This may suggest the influences of El Nin˜o-Southern Oscillation and solar activity on tree growth in the Qinling Mountains.These findings will help us understand the growth response of L.chinensis to climate change in the Qinling region,and they provide critical information for future climate reconstructions based on this species in semi-humid regions.

Study on Climate Change Characteristics in Western Qinling in the Past 41 Years

[Objective] The research aimed to examine climate change characteristics in western Qinling during 1967-2007. [Me^od] Based on the data of temperature, precipitation, sunshine duration, relative humidity and evaporation capacity derived from 17 weather stations, we analyzed the climatic change characteristics in western Qinling in the past 41 years, r Result] Increase magnitude of the annual mean temperature was 0.30 ℃/10 a in the past 41 years. Annual precipitation averaged 802 mm and varied non-significantly during the 41 years, while precipitation in spring significantly decreased by 13.68 mm/10 a. Besides, annual sunshine duration and annual mean relative humidity both decreased non-significantly, in contrast to annual evaporation capacity which showed an insignificantly increasing trend. Compared among southern, central and northern areas of the western Qinling, annual mean temperature, precipitation and relative humidity showed decreasing trends from south to north, while annual sunshine duration and annual evaporation capacity showed inversely increasing trends. [ Condusionl Thus, our research could provide reference basis for ecosystem stability and related research in western Qinling.