Effects Of Climate On The Radial Growth Of Larix Gmelinii Under Different Competition Intensities

In this thesis,the Grass-Larix gmelinii forest and Ledum palustre-Larix gmelinii forest of Chaocha Forest Farm in the Greater Khingan Mountains of Genhe Forestry Bureau were studied.By analyzing the relationship between the radial growth of trees and meteorological factors under different competition intensities,the model was combined with the current meteorological data and three climate scenarios sharing the social and economic paths in the future.In order to predict the future growth trend and change amplitude of Larix gmelinii under the background of climate warming,the main results are as follows:(1)The proportion of Larix gmelinii in the middle and small diameter classes of the two forest types was relatively high,and the distribution characteristics of the diameter order were "anti-J-type".Medium-heigh Larix gmelinii accounted for the majority,and the tree height distribution characteristics were normally distributed.(2)The growth ring width index of Grass-Larix gmelinii showed wide rings in 1903,1920,2009 and 2013,and narrow rings in 1911,1935,1967,2008,2012 and 2018.The growth ring width index of Ledum palustre-Larix showed wide rings in 1903,1869,2019,2010 and 2013,and narrow rings in 1886,1911,1972,1990,2003 and 2012.(3)The dendrochronology of the two forest types was positively correlated with monthly precipitation.The dendrochronology of Grass-Larix gmelinii was negatively correlated with the monthly average temperature,monthly average minimum temperature and monthly average maximum temperature in March of the same year.The dendrochronology of Ledum palustre-Larix gmelinii was negatively correlated with the monthly average temperature and monthly average maximum temperature in March of the same year.(4)With the intensification of global warming trend,high temperature will inhibit the radial growth of Larix gmelinii,and the radial growth of Larix gmelinii will present a negative growth trend.Under the medium and high competition intensities of Grass-Larix gmelinii,the radial growth of trees showed a positive trend only in the 2050 s under the sustainable development model.Under the low competition intensity of the Ledum palustre-Larix gmelinii,the radial growth of trees showed a positive trend in the 2090 s under the conventional development mode was dominated by fossil fuels.