Study On The Radial Growth And Spatial Climate Response Of Pinus Sylvestris Var. Mongolica In Plantations In Jilin Province

According to dendrochronological methods,Pinus sylvestris var.mongolica tree-ring samples of plantations were collected in Jilin Province.31 chronologies of tree ring width(RW),earlywood width(EW)and latewood width(LW)were developed by using Friedman curve to detrend for the tree ring data,respectively,and formed the tree ring data bank of Pinus sylvestris var.mongolica in Jilin province.The correlations between the three kinds of chronologies and climate factors(monthly precipitation and monthly mean temperature)and their spatial variations were studied.Basal area increment(BAI)was used to evaluate the P.growth in order to investigate the radial growth(RW,EW and LW)of P.of different responses to varying local climate conditions.The main results are as follows:1.The analysis of statistics of the chronologies indicated the high quality which meets the dendroclimatology standard,including Correlation with master series,Mean Sensitivity,Standard deviation and Expressed population signal.The chronologies contained abundant environmental information and were suitable for relatively shorter temporal-scale dendroclimatology study.2.According to the results of correlation analysis between chronologies and monthly precipitation and monthly mean temperature,April to June precipitation were found to mainly positively influence radial growth of RW and EW.The effect of precipitation from July to September on RW and EW presented inconsistency for all sites.However,precipitation from May to September were found to mainly promote radial growth of LW.Compared with precipitation,the temperature of March and April mainly promotes RW,EW and LW.However,May and June temperature inhibited radial growth of RW and EW,while the LW showed the promotion in the east and inhibition in the west.The correlations between three kinds of chronologies and climate factors of growing season(May-August)showed that precipitation mainly promoted tree growth,while temperature inhibited tree growth.Nevertheless,the correlation coefficient varies in spatial,which indicated that the growth of P.was influenced by regional hydrothermal conditions.3.It can be seen from the spatial distribution of the correlation coefficient,the growing season(May-August)precipitation has the strongest promoting effect on RW and EW in the central of study area,also the effect of EW has obvious spatial gradient,the promotion effect is gradually weakened from the central to the northwest,and becomes inhibitory the northwest.The promoting effect of March and April temperature to EW also has obvious spatial gradient variations,and the promotion intensity corresponds to the distribution of precipitation in spatial.It is indicated that the effect of temperature on the growth of EW increases with the increase of precipitation.However,the positive effect of the growing season temperature on the growth of LW from eastern humid region gradually reversed to the negative effects of the northwestern semi-arid region.4.The estimation results of BAI showed that BAI trends of all sites were declining,except for YMZ and STZ.The BAI sequence is aligned with year and age respectively,and we respectively contrasted the BAI trends and the BAI means during the same time interval by different alignment.It is found that warm and dry climate conditions in the northwest of the study area are not favorable to trees growth and the relatively cold and humid climate conditions in the central and east are more favorable for the growth and development of the plantation.