Variation Of C :n Ratio Of Natural Korean Pine Coniferous And Broad-leaved Mixed Forests With Different Recovery Years After Selective Cutting

Chemical elements such as carbon and nitrogen,as the basic elements of cells,participate in the various ecological processes of plant growth and development.They are essential nutrients for plants.Their content and ratio are closely related to various ecological processes.Ecological chemometrics links genes to biosphere through element content and proportion.However,the current research results do not reveal the role of Chemometrics in the study of ecology at the community and ecosystem level.In this study,the authors try to add the interference of restoration sequence to explain the changes of C,N and C:N in ecosystem under different restoration sequences.A series of forest restoration gradients(6yr,14 yr,25yr,36 yr,45yr,55 yr and 100 yr,respectively)with a series of selective cutting restoration years were selected from the mixed coniferous and broad-leaved forests in the north temperate zone.The samples of different organs(leaves,branches,stems and roots)of all plants in seven plots were measured.Through the determination of C and N content of the samples,the changes of C and N content and C:N content of plants and soil in different recovery years were analyzed,the variation of organ level and functional group level of typical temperate coniferous and broad-leaved mixed forest ecosystem was studied,and the variation rules along with the recovery years were explored to explore the utilization and decomposition of nutrients in the process of forest ecosystem succession.This study shows that the C content and N content of forest plants with different recovery years show regular changes,the N content shows an increasing trend with the growth of recovery years,and the C:N shows a regular downward trend;in different functional groups and organs,the change shows obvious differences,and the stability of leaf element content and ratio is the highest,In the community with the same recovery period,the C:N distribution of leaf and stem is more concentrated,but the C:N distribution of branch and root is quite different.The results of soil element determination show that in the soil with the same recovery period,the C:N ratio decreases with the increase of soil depth The trend is that the soil near the surface has higher C:N ratio.By analyzing the C and N contents of different functional groups and organs of plants and the variation of C:N in different recovery years,this paper systematically studied the change of element levels of all plant organs in different functional groups of temperate coniferous broad-leaved mixed forest with the recovery years,which provided a new viewpoint for revealing the nutrient utilization and decomposition of plants in different recovery years,which will provide a new perspective for forest Sustainable management,forest restoration and other fields provide theoretical basis.