Analysis On Driving Factors Of Carbon Density Of Larix Gmelinii Forests

The Greater Khingan Mountains is an important natural ecological barrier in north China.The Larix gmelinii forest is one of the top communities in The Greater Khingan Mountains.It is the largest and most widely distributed basic forest type in the Greater Khingan Mountains.In order to determine the effects of climate,soil,topography,stand factors and vegetation diversity on the carbon(C)density changes of Larix gmelinii forests.Based on field survey data of Larix gmelinii forests in the Greater Khingan Mountains,the structural equation model between C density of Larix gmelinii and environmental factors was employed by AMOS software to determine the main influencing factor of C density change of Larix gmelinii forests stand.The relationship between the main influencing factor and the change of C density was also established using principal component analysis and correlation analysis in this study.In the context of future climate change,it is of great significance to understand the dynamic change of forest C density and its coupling with climate change.The main contents and conclusions of the study are as follows:(1)By studying the 125 sample plots of climate,soil,topography,stand factors and vegetation diversity with latitude variation law confirmed 8 climatic factors including average temperature,annual average temperature,the hottest quarter the coldest quarter average temperature,annual average precipitation,precipitation,wet quarter most drought quarterly amount of precipitation,potential evapotranspiration,humidity is a trend of decrease with increasing latitude;There was no obvious change trend of soil with increasing latitude.Both topography and stand factors decreased with the increase of latitude.The species richness,diversity and evenness index of tree,shrub and herb layer increased with increasing latitude.(2)Among the climatic factors,the annual average temperature and annual average precipitation have the greatest impact on the carbon density of the Larix gmelinii forests,p H of soil factors had the greatest influence on C density of Larix gmelinii forests.Among stand factors,age and stand type had the greatest influence on C density of Larix gmelinii forests.Among the vegetation diversity,the vegetation diversity of the arbor layer and the vegetation diversity of the herb layer had the greatest impact on the carbon density of the Larix gmelinii forests.(3)Climate,soil,topography and vegetation diversity had positive effects on the carbon density of trees,shrubs and herbs in the Larix gmelinii forests.Stand factors had positive effects on the carbon density of trees and herbaceous trees,and negative effects on the carbon density of shrubs.The change of C density in Larix gmelinii forests was mainly controlled by climate variables,while vegetation diversity had little effect on the change of C density.(4)According to the quantitative relationship between climate and C density of Larix gmelinii forests,it is concluded that the C density of forest stands decreased with the increase of climate.