Analyze The Response Of Radial Growth Of Elm To Climate Factors In Otindag Sand Land

An analysis about eccentric growth and radial growth of Ulmus pumila var. sabulosa which located in the Baoshaodai and Naritu of Otindag Sand land was measured the ring width, earlywood and latewood width. The character of ring structures and time series variation of Ulmus pumila var. sabulosa were researched by theories and technique of dendrochronology. Effects of climate factors by chronology statistics of ring width, earlywood width and latewood width and the relationship of ring structures were analyzed. It is aimed to provide the basis for conservation elms in Otindag Sand land and natural regeneration, explore the possibilities for reconstruction the past climate in Otindag Sand land. The results showed that:1. There was a significant boundary between earlywood and latewood, because elm has a typical ring porous wood structure that the pores of earlywood are bigger than the pores of latewood. The tendency of time series variation of ring width and latewood width was consistent, and the latewood width and ring width, whose relationship reached0.98(p<0.01). There is no significant difference about average annual growth between Ulmus pumil var. sabulosa in Baoshaodai was2.25mm and that in Naritu was2.30mm. There is a singificant difference in (p<0.01) the earlywood widths of Ulmus pumila var. sabulosa grown in Baoshaodai and Naritu, they were0.64mm and0.73mm. The latewood percentage of of Ulmus pumila var. sabulosa grown in Baoshaodai and Naritu come up to60%.2. Disks of elms have different degrees of eccentric growth which seemed complicated and complex shapes in Baoshaodai and Naritu. The latewood widths of elms growing in Baoshaodai and Naritu had the same growth changing rule and two growth peaks with the ring widths. The radial cumulative growth curve of latewood widths and ring widths showed the trend double "S". Growth peak period of earlywood width had little change during the whole growth period which was different from ring width and latewood width. The radial cumulative growth curve of earlywood width was linear. The first radial growth of Ulmus pumila var. sabulosa in Baoshaodai happened in17～21year and that of Naritu was in15～19year. The mature ages are24of elms grown in Baoshaodai and21of elms grown in Naritu. The difference between these two places was3year. 3. Mean sensitivity, signal-to-noise ratio and expressing population signal of latewood width and ring width of elms grown in Baoshaodai and Naritu were higher than earlywood width. Comparison between the indicators of RES and STD, RES was more suitable to analyze the ring width and climate. Through ring index of RES and temperature and precipitation by correlation analysis and response function analysis, we found ring structures indicators were significantly negatively correlated and responsed with climate factors, which indicated that ring structures indexes can be used to reconstruct the past climate.