Response Of Radial Growth Of Larix Kongboensis To Temperature And Precipitation In Tibet Shergyla Mountain

In this study,based on the 200 core samples of Larix kongboensis at the east and west slope that can grow trees in Tibet Shergyla Mountain,combined with the meteorological data in the study area,combined with SPEI data and related data,linear regression,correlation analysis,M-K test and other research methods were used to try to construct the response relationship of endemic tree species to climate change under the background of climate change.Through this study,the following conclusions and progress are obtained:(1)The radial growth of Larix kongboensis is sensitive to climate change,which is mainly affected by the minimum temperature in the early growing season and has a significant negative correlation with the relative humidity at the end of the growing season.The radial growth of Shergyla Mountain Lulang and Jialuo Larix kongboensis was affected by the average temperature from January to April in the early growing season,and the humidity maintained a relatively consistent response.The Larix kongboensis annual ring index in Lulang was significantly positively correlated with the average temperature from January to April of the year,while the Larix kongboensis in Jialuo reached a significant positive correlation from February to March.At the same time,the radial growth of Larix kongboensis in the two plots was significantly negatively correlated with the relative humidity in May and July of the same year and had a significant lag with the relative humidity in July.Although the radial growth of Larix kongboensis in Jialuo and Lulang had obvious differences,it was consistent with the response relationship between temperature,precipitation,and relative humidity.(2)After the sudden change of temperature,the radial growth of Larix kongboensis was more significantly limited by the maximum temperature in the early growing season.The precipitation and relative humidity changed significantly compared with those before the sudden change of temperature,showing obvious inhibition.The radial growth of Larix kongboensis was only positively correlated with the average temperature in August of the year before the temperature mutation,but after the temperature mutation,the correlation changed to be positively correlated with the average temperature in January of the year,and negatively correlated with the average temperature change from July to September of the year,and the ’ hysteresis ’ was significant.The highest temperature was positively correlated with April before the temperature mutation,and then changed to a negative correlation from February to March,and the correlation with November of the previous year decreased.The correlation between precipitation and precipitation changed from non-correlation to negative correlation with precipitation from February to March and showed a significant lag with precipitation in November.Relative humidity also changed from negatively correlated with February to negatively correlated with May-July and September,and the lag phenomenon was significant.(3)There will be obvious differentiation response between precipitation and relative humidity at high altitude,while there will be obvious differentiation response between minimum temperature and precipitation at low altitude.Larix kongboensis grown in different environments has different degrees of differentiation response to the temperature after the mutation.For west slope and east slope trees,there are significant differential responses to precipitation and minimum temperature.Both are due to the increase in temperature,resulting in the radial growth of trees being disturbed by different environmental factors.However,under the continuous change of temperature,trees will adapt to the disturbance of this environment again.At the same time,with the continuous increase of temperature,trees growing in high altitude areas will also have a significant response to precipitation,and the minimum temperature in low altitude areas will become a new limiting factor for tree growth.(4)The differentiation of Larix kongboensis radial growth in west slope with climate change is more significant than that in east slope.The Larix kongboensis radial growth in the Jialuo area is more restricted by the average temperature during the growing season.The average temperature from July to August and November showed a more obvious ’ lag‘and showed a positive correlation with the average temperature in November of the previous year and January of the current year.After the abrupt change of temperature,the maximum temperature showed a more obvious limiting effect on the radial growth of trees in the early stage of the growing season,and it was positively correlated with the radial growth from February to June of that year(P > 0.05),and changed into a significant negative correlation(P < 0.05).The minimum temperature changed from most negative correlation to most positive correlation.The precipitation and relative humidity have changed significantly compared with the temperature before the abrupt change,showing obvious inhibition.The radial growth of Lulang is more obviously affected by relative humidity than that of Jialuo.It is negatively correlated with May-July and September of the year and shows obvious ’ hysteresis ’ with precipitation in July and September.