Response Of Radial Growth Of Pinus Tabulaeformis To Climate Change And Temperature Reconstruction In Funiu Mountains

Funiu Mountain is the north-south geographical boundary of China,as well as the important climate boundary of warm temperate zone and northern subtropical region of China.Funiu Mountain is the area sensitive to global climate change.Pinus tabulaeformis Carriere is an endemic tree species in China and an important tree species in northern China.Funiu Mountain is the southern boundary of Pinus tabulaeformis.The growth of Pinus tabulaeformis is susceptible to climate change.In this paper,the Pinus tabulaeformis samples from two sampling points on the north and south slopes of Funiu Mountain is taken as the research object.And a standardized chronologies of the tree ring width of Pinus tabulaeformis on the north and south slopes of Funiu Mountain are established.Correlation analysis and sliding correlation analysis were conducted to study the relationship between Pinus tabulaeformis and climatic factors at different slope directions in Funiu Mountain and the difference in response to rapid rise in temperature.Finally,the reconstruction of the minimum temperature of March in southern slope of Baotianman during 1918-2011 nearly 94 years and the analysis of the change characteristics was conducted.The following main conclusions are obtained:(1)The annual precipitation on the north and south slopes did not increase or decrease significantly during the study period(1957-2015),but the annual average temperature both in southern and northern slopes showed a significantly upward trend after 1984(R2=0.2396,P<0.05;R2=0.34,P<0.05).The southern slope is superior to the northern slope in light time,precipitation,and soil water supply.So the southern slope of Pinus tabulaeformis can better adapt to changing climatic condition,and the northern slope of Pinus tabulaeformis is more susceptible to climate factors.(2)The dynamic analysis of the annual ring width of Pinus tabulaeformis and its correlation with climatic factors show that the combined effects of slope direction,temperature and precipitation are the main factors affecting the radial growth difference of Pinus tabulaeformis in different slope directions.The radial growth of Pinus tabulaeformis on the south slope presented significantly positively correlated with the precipitation of July(r=0379,P<0.01)and average temperature of March(r=0.340,P<0.01).It also showed significantly negatively correlated with the lowest temperature of January(r=-0.323,P<0.05).The radial growth of Pinus tabulaeformis on North slope was significantly positively correlated with precipitation(r=0.435,P<0.01)and PDS1(r=0.293,P<0.05)of June,the average temperature(r=0.339,P<0.05)of February,the maximum temperature(R=0.416,P<0.01)of April,the average temperature(r=0.334,P<0.05)and the minimum temperature(r=0.32266,P<0.05)of September.However,the radial growth of Pinus tabulaeformis on the northern slope was also significantly related to the temperature and precipitation in the late autumn and early winter(October-December)of the previous year,indicating that there was a "lag phenomenon" in the response of the Pinus tabulaeformis to temperature and precipitation.(3)The slide correlation analysis of Pinus tabulaeformis "with different slope directions and the temperature and precipitation in the growing season shows that the radial growth of Pinus tabulaeformis on the north and south slopes of has different responses to temperature and precipitation throughout the study period.The Pinus tabulaeformis on the southern slope was greatly affected by the precipitation of March,and the significant correlation period was after 2009,while the radial growth of the Pinus tabulaeformis on the northern slope was greatly affected by the precipitation of March and July.It is relatively closed,and the periods with significant correlation are all around 2000.The radial growth of Pinus tabulaeformis on the southern slope is more stable than that on the north slope,and the radial growth of Pinus tabulaeformis on the northern slope is more sensitive to temperature changes in the early(March-April)and late(August-September)seasons.There was a significant positive correlation(P<0.05),which may be related to the aspect.It is estimated from the sliding time that the rapid temperature increase leads to the southern and northern slopes of Pinus tabulaeformis becoming more sensitive to temperature changes,and it is unstable due to the precipitation during the growing season throughout the study period.(4)The analysis of the differences in the response of radial growth of Pinus tabulaeformis to rapid warming in different slope directions shows that the positive correlation between the north and south slopes of Pinus tabulaeformis and PDSI increased after rapid warming,especially in the vigorous growing season(June-August).The rapid increase of temperature led to a negative correlation between the growth of Pinus tabulaeformis and temperature on the south slope and a positive correlation with precipitation.The positive correlation between Pinus tabulaeformis and temperature and precipitation on the northern slope is enhanced.In other words,climate change promotes the radial growth of Pinus tabulaeformis on the northern slope.(5)The climate reconstruction sequence of the minimum temperature in March in Baotianman area on the south slope is basically consistent with the change trend of the measured temperature,which can be fitted well.In the history of the Baotianman area,there were relatively obvious cold and warm periods.For example,1930-1942 was a relatively obvious warm period,and 1943-1952 was a distinctly cold period.Moreover,the number of colder years and warmer years in the Baotianman area are almost the same,and the number of cold and warm years is the same,indicating that the minimum temperature change in March in this area is relatively stable.In summary,there are differences in the response patterns of radial growth of Pinus tabulaeformis to climate change on the northern and southern slopes of Funiu Mountain.The radial growth of Pinus tabulaeformis on the southern slope was significantly affected by temperature,and the radial growth of Pinus tabulaeformis on the northern slope was affected by the combined effect of temperature and precipitation.Moreover,the radial growth of Pinus tabulaeformis is more sensitive to the combined effects of temperature and precipitation.After rapid warming,the response patterns of Pinus tabulaeformis on the southern and northern slopes to climate change have changed greatly,and the warming can promote the radial growth of Pinus tabulaeformis on the southern and northern slopes.The temperature reconstruction sequence of March in the southern slope area fits well with the measured temperature trend,and the reconstruction sequence shows that the minimum temperature change of March in the south slope area is stable.