| Global climate change brings more impact to human society and ecosystems.Shiren Mountain is located in the eastern section of the Qinling Mountains and is in the transition zone between the northern warm temperate zone and the southern subtropical zone.Due to its special natural geographical environment,climate change is sensitive.Regional climate research is of great significance.This study takes the tree chronology of Pinus armandii in the Shirenshan area on the northern slope of Funiu Mountain as the main line of research.It uses principal component analysis,correlation analysis,response function analysis and other methods to respond to the tree ring from a single point weather station.The regional climatic factors responded by establishing an ecological model of the regional Pinus armandii tree ring to determine the main climate limiting factors affecting the growth of Pinus armandii trees in the region,and explore the potential of using tree-ring climatology to reconstruct past climate change.Provide scientific basis for the formulation of forest management measures under climate change.Firstly,this study takes Huashan pine in the Shirenshan area on the northern slope of Funiu Mountain as the research object.Based on the principle and method of tree ring theory,the tree annual ring width standard chronology and difference chronology of four sampling points are established and utilized.Principal component analysis obtained the standard chronology and the first principal component of the difference chronology((PC1))synthesized the regional tree annual chronologySecondly,the relationship between the four meteorological stations near the sampling point of Shiren Mountain and the changes of regional meteorological factors were analyzed.Finally,the meteorological data of monthly average temperature and monthly precipitation of the two stations in Qixian and Nanzhao were selected for comparison.The results show that the tree ring chronology of the four sampling points has a good correlation with the meteorological factors of Jixian County.In general,the width of Huashan pine tree was significantly negatively correlated with the temperature in May and June,and was significantly positively correlated with the precipitation in May,and the significant response of the standard chronology was better than the difference chronology.The YS01 standard chronology was significantly negatively correlated with the monthly average temperature of the first,second,third,fourth,fifth,and seventh months of the year,and from November of the previous year to March of the same year.The precipitation in October showed a significant positive correlation;the YS01 difference chronology was significantly negatively correlated with the precipitation in March of the county.The standard chronology of YS02,YS03 and YS04 was significantly negatively correlated with the average temperature in May and June of the county,and was significantly positively correlated with the precipitation in May,and the YS03 standard chronology was significantly negative with the precipitation in August.Relatedly,the YS04 standard chronology was significantly negatively correlated from December to January of the previous year.Third,the correlation analysis also found that the first principal component(HPC1)of the high-altitude standard chronology and the difference chronology was significantly negatively correlated with the monthly mean temperature of May,May and June in Jixian County,and was significantly different from the monthly precipitation in May.The positive correlation was significantly negatively correlated with the precipitation in winter,from December of last year to January of the same year,indicating that the growth of Pinus armandii in high altitude area was affected by the lag of the hydrothermal combination in May and the precipitation in winter last year.The low-altitude,high-altitude chronology and the whole regional chronology modeled the temperature and compared the temperature change trend.It was found that the growth of Pinus armandii trees decreased significantly with the increase of temperature,and the growth of Huashan pine trees at different altitudes was obvious in response to temperature changes.Fourth,the relationship between the regional tree ring chronology and the climatic factors of a single weather station indicates that the standard chronology and the difference chronology(PC1)are significantly negatively correlated with the average temperature in May of that year,and the precipitation in May of that year.The amount was significantly positively correlated,and it was significantly negatively correlated with the precipitation in August of that year.It is obvious that the hydrothermal factor in May is the main limiting factor for the growth of Pinus armandii.The standard chronology and the difference chronology(PC1)are related to Nanzhao.There was a significant negative correlation between the average temperature and precipitation in May of that year;the difference with Ganxian County was obviously related to the south slope of Funiu Mountain.Finally,this paper analyzes the relationship between regional tree ring chronology and regional climate factors.The standard chronology(PC1)was significantly negatively correlated with the monthly mean temperature in May,and was significantly positively correlated with the monthly precipitation in May of that year,and was significantly negatively correlated with the precipitation in August of that year and July-September of that year,apparently from the region.Considering the tree ring growth of Pinus armandii in Shirenshan area is restricted by the hydrothermal factor in May and the precipitation from July to September;the difference chronology(PC1)is significantly negatively correlated with the regional average temperature in May,and from July to November.The monthly mean temperature showed a significant positive correlation,which was significantly negatively correlated with the monthly precipitation of July,August and July-September,and from December of the previous year to January of the current year.Therefore,the regional difference chronology showed the average temperature of May.The hydrothermal combination of September-September is the limiting factor for the growth of Pinus armandii tree rings.Based on plant physiology and the relationship between multiple chronology and meteorological data,it can be concluded that the growth of trees and temperature and precipitation in Huashan Mountain of Shirenshan is similar to the response of tree width and climatic factors in the northern Qinling Mountains,that is,water is the growth of trees.The limiting factor,the soil water stress caused by high temperature has a significant effect on the radial growth of trees,and the temperature influence is stronger than precipitation.According to the above-mentioned significant correlation factors of tree ring growth,the ecological model of the regional climate elements response to climate response was established.The simulation results of the model are in good agreement with the actual values.Taking the regional average temperature change trend in May and the regional standard chronology(PC1)simulated in the regional monthly average temperature factor as an example,it is concluded that the growth of the regional Pinus armandii trees is more sensitive to the response to the warming in May.Although we have obtained the preliminary results of the Huashan pine tree ring climate record research through the above research,there are still many other work that can be further deepened,such as the altitude gradient and the aspect of the tree ring to climate change response,comprehensive meteorological indicators and radial growth.Relationships,etc.It is hoped that in the future,we can combine the research methods of various tree rings to deeply analyze the impact of global climate change on tree growth.. |
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