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Tree Ring Based Climate Research For Luoxiao Mountain

Posted on:2016-07-10Degree:MasterType:Thesis
Country:ChinaCandidate:L L LiFull Text:PDF
GTID:2370330461458517Subject:Physical geography
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Affected by the warm-humid climate and lush vegetation,the relationship between trees and climate is complex.Coupled with the increasing human activities and the difficulty in finding old trees,the dendroclimatology research lagged behind in the East Asian monsoon region compared to other climatic zones.Luoxiao Mountain in this study is located in the border region of Hunan and Jiangxi Provinces.In this study,the responses of tree growth to climate at different altitudes were investigated to deepen our understanding of relationship between tree growth and climate factors.This will provide a basis for the climate reconstruction of southeast China.Tree ring samples from three different altitudes were collected at 150?350m of Daowushan(DWS),600?700m of Pusaao(PSA)and 1390m of Jinggangshan(JGS).Wood species are Pinus massoniana Lamb.and Pinus taiwanensis Hayata.In addition,the Pinuas taivanensis Hayata samples from 1530m of Jiulongshan(JLS)in Zhejiang Province and 1650?1700m of Guniujiang(GNJ)in Anhui Province were also collected to compare with that of JGS.After preprocessing with the standard laboratory experiment method and implementation of cross-dating,tree ring width of the five samples were detrended by using a cubic spline with step-size equal to 67%of the series length.Finally,tree ring width standardized(STD)and residual(RES)chronologies were established after normalization.The correlation of STD and RES chronologies to climate factors showed that both chronologies in the DWS are correlated negatively with temperature in early spring(March)and summer(June to September),while positively with precipitation and air humidity for the same period.PSA chronologies correlated positively to temperature in winter and spring(January to April),while negatively to temeprature in summer(June to September).JGS chronologies correlated positively to temperature in March,while negatively to temperature in May.The comparison of results among JGS,JLS and GNJ indicated that trees growth in high altitudes correlated positively to early summer(June to July)temperature,while negatively to precipitation simultaneously.This correlation is more significant in high altitude area(?1500m).Moreover,the responses of tree-growth to climate at different altitudes might be expressed as follows:1.Temperature in early spring can influence tree growth remarkably.As the altitude increases,this influence can change from positive to negative,and it's most significant in high altitude area.2.The negative effect of summer temperature on tree growth weakened as the altitude increases.On the other hand,tree growth in low altitude correlated positively to relative humidity.The inhibitory effect of high temperature on tree growth can embody in some indirect ways,such as leading to the water stress by increasing evapotranspiration and stomata closure,and reducing the photosynthesis of plants.3.The correlation between tree growth and prior summer temperature(precipition)changes from negative(positive)to positive(negative),and it's more significant in high altitude area.This proved that the increase of summer temperature in high altitude area falls in the range of suitable tempreature of Pinus taiwanensis Hayata,so it can promote tree growth.Whereas high precipitation can restrain tree growth through high air relative humidity etc.Translation function between DWS STD chronology and temperature from June to September since 1815 was established,which could explain 27.2%of the variance in 1960?2013.The summer temperature has experienced four warm periods(i.e.,late 1840s?1880s,1920?1930s,1950?1960s,and 2000s?;)and four cold periods(i.e.,1820?early 1840s,late 1880?1910s,1940s,1970?1990s).The cold and warm periods are consistent with those of Macheng and Funiu Mountain.
Keywords/Search Tags:Luoxiao Mountain, tree ring width, climatic response, summer temperature reconstruction
PDF Full Text Request
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