Analysis Of Regional Differences In The Response Of Masson Pine Tree Ring Width To Climate Factors

This study aimed to explore different application of earlywood?EW?,latewood?LW?,and total ring?TR?widths of Pinus massoniana Lamb?PM?in various areas to climate analysis,and it also investigated how radial growth of PM would be affected in different subtropical regions in the background of global warming.This study selected five research areas which were located in eastern,western,central,southern and northern parts of main PM distribution range respectively.Finally the EW?LW and TR width standardized chronologies?STD?and residual chronologies?RES?have been established in each area for the following analysis.The results showed that:1)Most of the significant correlations between all three types of chronologies and the climatic factors in each area were highly coincident.It reflected that the width indicators of PM were sensitive to climate changes.The mean sensitivities of EW and LW width chronologies in all regions were slightly higher than that of TR width chronologies.2)A spatial difference existed in the sensitivity of the tree ring width of PM to climate indicators.The high temperature in summer had strong inhibitory effects on the growth of PM in southern and northern research areas?R mean min-temperature between 7-8,total ring width chronology in south area=-0.540,p<0.01:R mean max-temperature between 6-7,latewood width chronology in north area=-0.366,p<0.01?.In the early stage of growing season,the increasing temperature was beneficial to the radial growth of PM in the areas with ample water.But in the northern area where water was relatively deficient,the temperature rise would be negative to the radial growth of PM.To present the general relationship between the width of the PM and climatic factors in the subtropical region,this study combined all PM tree-ring data and climatological data from five regions into one tree-ring-climate database.All the data of the database was processed by Pearson correlation analysis.The results showed that the LW width index and the percentage of latewood rate of PM were better than the EW and the TR width in a larger regional scale.The correlation coefficients between percentage of latewood rate and annual mean temperature,annual precipitation were 0.749 and 0.457 respectively.The correlation coefficients between LW width and annual mean temperature,annual precipitation were 0.645 and 0.390 respectively,p<0.01.Based on the above analysis,this study attempted to establish the universal relationship between PM width index and climate changes in subtropical regions for the first time.It included the relationship between the percentage of latewood rate of PM and annual mean temperature,annual precipitation:YLWP=0.042T+0.0000386P-0.308?R=0.759,p<0.001?.In addition,the relationship between latewood width index of PM and annual mean temperature,annual precipitation was as follows:Y_LW=0.142 T+0.0001 P-1.590?R=0.653,p<0.001?.The two functional relations indicated that the latewood radial growth of PM in the subtropical region would be facilitated by the increasing temperature.