The Response Of The Growth Of Larix Gmelinii To The Climate Change In Daxin'anling Area

Daxing Anling Area is located in the south edge of Eurasian permafrost belt and the bright coniferous forest of cold temperate zone.It is the highest latitude and the fastest warming in the climate sensitive area in our country.It is also one of the climate vulnerability area.The Larix gmelinii which is sensitive to climate change is the local zonal vegetation.In this research,the tree ring of Larix gmelinii is our research object which was collected in Hanjiayuan,Tahe and Xinlin in Daxing Anling area.We set a residual chronology of the tree ring from 3 sampling points to analyze the statistical characteristic parameters of the annual table.Based on the measured data(average temperature,average maximum temperature,average minimum temperature and precipitation)of meteorological stations from 1972 to 2018,we analyzed the correlation between radial growth and climate factors of tree wheels.Based on the analysis of response function,we use climate variables to simulate and the change of its radial growth,and made contrastive analysis about of the Basal Area Increment(BAI).The main conclusions are as follows:(1)In this research,we established a residual chronology of the tree ring from 3 sampling points including Hanjiayuan,Tahe and Xinlin,and the statistical parameters are applicable to the study of dendroclimatology.The tree ring of samples taken at high latitudes and altitudes contain more climate information.(2)The BAI of Larch in Hanjiayuan showed a very significant upward trend,but it grows slowly.The BAI of Larch in Tahe experienced a change process from “growth” to “stability” and finally “recession”.The BAI of Larch in Xinlin reached a stable situation after the accelerated growth in the previous period.From the long-term trend,the future distribution of Larch in Daxing Anling area will shrink to high latitudes and high altitudes area.(3)The monthly and seasonal correlation analysis between the width of its tree ring and climate factors as well as the sliding correlation analysis showed that the radial growth of Larch in Hanjiayuan was significantly and positively related to the average maximum temperature in the last growth season,while it was significantly increased gradually,which was negatively correlated with the precipitation in the last growing season.It was also negatively correlated with the average minimum temperature in July.The radial growth of Larch in Tahe showed a significantly negative correlation with the average minimum temperature of the last July,which was strengthened first and then weakened.Besides,it showed a significantly negative correlation with the average winter temperature,the average maximum temperature and the average minimum temperature of the previous year,while it also showed a negative correlation(with a significant sudden)with the average temperature and the average maximum temperature of the current year from June to July.The radial growth of Xinlin Larch was negatively correlated with the precipitation in the last growing season,negatively correlated with the precipitation in December of the previous year,and negatively correlated with the average temperature,average maximum temperature and average minimum temperature in March of that year.However,all of the significance gradually decreased so that it was not significant.The complexity of geographical environment and the diversity of local climate lead to different responses of larch growth to climate change in different sampling sites in the Daxing Anling area.(4)Combining the analysis methods of sliding correlation and spatial correlation,we use the data set of CRU grid point to analyze the spatial response dynamics of the chronology of the width of its tree ring in Tahe and the average maximum temperature from June to July of that year.We found that the spatial correlation between the local Larch growth and high temperature in summer was shifted to the south-east,which may be related to the weakening of the summer wind in East Asia and the rapid increase in temperature.(5)Based on the analysis of response function,climate variables simulated the radial growth changes of Larch.and the imitative effect between the simulation values of the Tahe and the measured values was the best,which was followed by Xinlin.The imitative effect of Hanjiayuan was slightly worse.The level and trend of change between the simulation value and the measured value are close so the response function model is built successfully.