The Study On The Response Of Contemporary Tree Ring Width Of Castanopsis Fargesi And Cinnamomum Camphora To Climate Change In Dagangshan

Dendroclimatological approach is significant in global climatic changes for its precise dating,high continuity, high resolution and easily obtained duplicates. The chronologies have beenused as a very good replaced reference for the climate flux in the research. It has been used inmore fields to resume the history environment process since 20th last century, such as Ecology,Hydrology, and Archaeology and so on. The dendrochronology hypothesizes the climatechange as a rule in the past; the tree-rings can be used to show the environment fluxes lawthrough wiping off the nature growing trend. Only a few works have been done in tropical andsubtropical regions due to relative low sensitivity there. There is a fact that the climateobservations are in a short time and little sites characteristics in all over the China. They are toopoor to do some long time research. There are many ecological researches in Dagangshan StateForest Ecosystem Research Station in Jiangxi Province, it's very important to rebuild thehistory climate for the study in this area. So we selected the area for the study object.After a popular investigation and a series filter processing, we choose two broad-leaved speciesCastanopsisfargesii and Cinnamomum camphora as the object in the end. We get the coresthrough drilling two holes into the tree in the contour line direction, after a serious treatment:fastening, drying and polishing, we can begin the measurement of tree-ring width by theLintab5 and its software TSAP (time series analysis presentations) with the computer, and thencheck the validity of the series we got through COFECHA software: At last, we can wipe offthe mistake series or little sensitive series from the ".out" file. Using the ARSTAR software toget off the growing trend of trees, and then transform the series into a index form. In the end,we can get a tree chronology of three forms. Through the correlation analysis between thechronology and the contemporary history climate data, we can get the correlation and theresponse function, and then we can set up the relationship between them. After the statisticalanalysis, we can get the conclusion that:1. The statistical results show that: The two species we chose tree-ring width series aresensitive to climate change in the past. After the check, the tree-rings show that they have thecommon property in the climate variance in the history; they can be used in dendrochronologyresearch.2. We choose mean monthly temperature and total monthly precipitation as the climate factors.The climate response models were established from the preceding to September the current November with the climate elements. The conclusion of the response analysis is similar to theresult of the correlation analysis. We found that the residual ring width has a significantpositive response to mean average temperature and a significant negative response to totalmonthly precipitation from last December and April to August. The Castanopsis fargesii hadlow significance levels in temperature in the growing season, and a negative response to therainfall with 95ï¼…significance levels in July. The Cinnamomum camphora had a similarresponse rule to the temperature and precipitation, but almost one month later. Other while,Cinnamomum camphora had a negative correlation coefficient with the December precipitation.Compared with Castanopsis fargesii, the latter had a more complex process. Cinnamomumcamphora had a better correlation relation with the climate factors in different time.Comparing with the month change, the chronology had a low correlation confidence to theseason change, but a higher relationship to a certain time. The results show that the tree-ringwidth of Cinnamomum camphora had a significant positive response to mean averagetemperature from April to May, and had a significant negative response to total monthlyprecipitation in the same time. So we can suppose that the continue influence of the climatefactors to the width growth much more. The moisture index response improved the hypothesisfor further, but the time had been changed to May, June, August and September.3. We try to set up the physiological mechanism of width tree-ring in the condition of highdegree and abundant precipitation in the subtropical area, but it needs to be improved by morefacts in the future.4. We try to reconstruct the history of the moisture index .The result of reconstruction of thesignificance moisture index for Cinnamomum camphora show the trend is right, but the specialstatus is not perfect. Maybe the unusual climates in a short time play an important role in theprocessing.