| Pinus sylvestris var.mongolica was an important component of forest ecosystem in northeast China,at the same time it was one of the main tree species in order to create a windbreak sand fixation forest,soil and water conservation forest and farmland shelter forest in a semi-arid desert area.Pinus sylvestris var.mongolica had obvious economic and ecological benefits,so it had the value of being studied and protected.In recent decades,greenhouse effect had already increased in China's northeast and Inner Mongolia area;The ecological environment had been varying degrees of damage.In this context,so in order to further reveal the growth differences and to select the good provenance of Mongolian Scotch Pine(Pinus sylvestris var.mongolica)at Maoershan Area of Heilongjiang Province in China,we investigated the DBH,height,volume,crown width,ring width and survival rate of 31-yearsold Mongolian Scotch Pine at Maoershan area.The good provenance(AES,GF,HHEJ,KLS,TQ,HDG and HDG of 7 provenances)was selected by using variance analysis,multiple comparison,correlation coefficients and principal component analysis,seven Pinus sylvestris var.mongolica tree-ring chronologies for plantations in Maoershan region were developed based on the dendrochronological theory and methodology.To explore the divergent responses of tree growth at different provenances to the climatic factors,the response analysis,correlation analysis and principal components analysis of variance between tree rings and climatic factors were conducted.So we mainly draw the following conclusions:We got that the DBH exhibited extremely significant differences(P<0.01),the volume and crown widtht exhibited significant difference(P<0.05),the height exhibited no significant difference among the different provenances.All the traits we investigated showed no significant differences among different blocks.The tree ring width Tuqiang provenance was the maximum(3.69mm)while its survival rate was the minimum(56.67%).The DBH,height,volume,crown width and ring width did not exhibited significantly correlation to latitude and longitude of provenances,except for the survival rate which significantly and negatively correlated to latitude(P<0.01)and longitude and significantly and positively correlated(P<0.05)to altitude.Therefore the genetic variation of Mongolian Scotch pine was no obvious among the various traits.According to the principal component analysis,the composite index score of Tuqiang provenance was highest(2.972).The growth traits of 31 years old Mongolian Scotch pine showed difference among provenances which of the Tuqiang provenance was best,and the HHEJ and GF provenances were better than that of the others.The Tuqiang provenance showed the best application potential at Maoershan area.Compared with the growth traits of Pinus sylvestris var.Mongolica plantation of 31 years old,in the 17-years-old provenances of Pinus sylvestris var.Mongolica provenances,the DBH,tree height and volume were significantly different(P<0.01)among provenances.It showed no significant differences(P>0.05)among different blocks.This difference between 17-years-old Pinus sylvestris var.Mongolica provenance forest and 31-years-old was mainly due to genetic factors.Seven Pinus sylvestris var.mongolica tree-ring chronologies for plantations in Maoershan region were developed based on the dendrochronological theory and methodology.Results showed the winter temperature(12,1 month)was the main limiting factor for the radial growth of Pinus sylvestris var.mongolica in different provenances in Maoershan area.The tree ring from different Pinus sylvestris var.mongolica provenances in the study region had a similar trend.Among 7 provenances,the ring width of six provenances showed an increasing trend in the initial stage.The radial of provenances form Aershan,Gaofeng,Honghuaerji and Kalunshan had significantly positive correlation with temperature in current February;The radial of provenances form Handagai and significantly positive correlation with temperature in last April.The radial of provenances form Gaofeng,Tuqiang and Kalunshan significantly positive correlation with monthly precipitation in current June.The radial of provenances Aerahan,Gaofeng,Jinshan,Kalunshan,Honghuaerji and Tuqiang had significantly negative correlation with monthly precipitation in last August.It was concluded that the width growth of different Pinus sylvestris var.mongolica provenances grew faster at early stage.The width growth had positive correlation with temperature in Februare and precipitation in June,but negative correlation with precipitation in last August.In this study,the tree-ring chronologies of 7 Pinus sylvestris var.mongolica provenances in Maoershan were developed. |
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