Response Of Radial Growth And Recruitment Of Pinus Koraiensis To Climate Change In The Lao-ye-ling Mountains

Climate warming affects trees growth and recruitment and changes the stability of forest ecosystem structure and function.Pinus koraiensis is dominant species of broad-leaved Korean pine forests which is the zonal climax vegetation communities in northeast China.P.koraiensis playes an important role in biological carbon sequestration,soil and water conservation and ecological environment protection.This study took P.koraiensis in Lao-ye-ling Mounains as the research object,and aimed to probe the effect of topographic factors and temperature increase on the relationship between P.koraiensis growth and climate and the stability of P.koraiensis growth,reconstruct the growth release/suppression history of P.koraiensis in this area,and discover the effects of climate change on the recruitment of P.koraiensis in the past 30 years.The results were as follows:(1)Annual mean temperature,mean minimum temperature and mean maximum temperature increased 0.36?/10a,0.53?/10a,0.26?/10a respectively after 1961(p<0.01),and the temperature increase speed of winter and February were fastest.The annual total precipitation changed weakly.The topographic factor affected the response of P.koraiensis growth to climate,and the effect of slope aspects was bigger than slope position.The radial growth of P.koraiensis in southwestern slope was positively correlated with the precipitation in June(p<0.01),but was negatively correlated with the mean temperature and high temperature in the growing season and June.The radial growth of P.koraiensis at southeast slope was negative correlated with the precipitation in August of last year,but was positively correlated with the low temperature in winter of last year and February to April of current year,which was significant different with that of southwest slope.Slope position weakly affected the relationship between P.koraiensis growth and climate response at upper and lower southwest slope.The negative correlation between the growth of P.koraiensis at upper slope and the high temperature in autumn of last year and September of current year was stronger than that at lower slope;and the positive correlation between P.koraiensis at lower slope and precipitation in growth season of current year was stronger than that at upper slope,and the negative correlation between P.koraiensis at lower slpoe and high temperature was stronger than at upper slope.(2)The stabilization of radial growth of P.koraiensis and its response to climate was changed with temperature increase.P.koraiensis radial growth was inconsistent with temperature increase after 1980.P.koraiensis radial growth positively increased with gentle temperature increase before 1980 which was negatively correlated with the precipitation in July and August of current year,and was positively correlated with the mean temperature and high temperature in July of previous year and the low temperature in September of last year and the low temperature in March,April,June,September of current year.However,P.koraiensis radial growth sharply decreased with rapid temperature increase after 1980 which was negatively correlated with the precipitation in June,the mean temperature and high temperature in June and July of current year and the temperature in July and mean temperature and high temperature in September of last year.The temperature of growing season gradually inhibited P.koraiensis growth,but the precipitation gradually promoted P.koraiensis growth with temperature increased.The radial growth of P.koraiensis would decrease 52.6%if temperature and precipitation increase 2? and 20%in the future.(3)The growth release of.koraiensis concentrated in the periods of 1920-1945,1965-1975 and 2000-2005,and mainly expressed by major growth release which experienced 1.77 times each tree.The growth suppression concentrated in the periods of 1905-1920,1980-1985,1990-2000 and 2005-2010,and mainly expressed by slight growth suppression which experienced 1.51 times each tree.Climate change was the main factor causing large-scale growth release/suppression of P.koraiensis.The low temperature or drought stress could induce P.koraiensis growth suppression,but the excellent water and temperature could promote.koraiensis growth release in the growing season.Microenvironmental changes were the main factor that caused small-scale growth/inhibition events in forests.(4)The annual recruitments number of P.koraiensis has gradually increased in past 30 years.P.koraiensis recruitment number was mainly affected by temperature and precipitation,which was negatively correlated with annual total precipitation and precipitation in July,but was positively correlated with continuously high temperature in growing season and the temperature in autumn,and accumulated temperature(?10?).Temperature increase was the main reason for the increase of annual recruitment of P.koraiensis.The radial growth of P.koraiensis and its response to climate were unstable.Topographical factors affected the relationship between radial growth and climate.The radial growth of P.koraiensis was declined after 1980 due to temperature fast increase which increased growth suppression events frequencies,while promoted P.koraiensis recruitment.If temperature continuely increase,the radial growth and recruitment of P.koraiensis will both decline obviously,and some forest management activities are needed to maintain the growth and recruitment of P.koraiensis.