Effect Of Target Tree Management On Community Structure Of Secondary Evergreen Broad-leaved Forest

Tending to explore management technology based on secondary evergreen broad-leaved forest effectively improving the quality of forest and ecological function,this article selects distribution in Jiande,Zhejiang Province Yang Village bridge town secondary evergreen broad-leaved forest as the research object,the fixed sample,set up long-term implementation of target tree business processing and banned(control)experiment,carried out the target tree management of forest stand structure and study the influence of fine root growth,advantages of tree species,analyzes the advantage of blade and correlation function fine root traits,in order to evaluate target tree management effects on secondary evergreen broad-leaved forest community structure.The main results are as follows:(1)Target tree management significantly improves stand structure and accelerates stand growth.After 2 years of target tree management,stand density decreased by 56.74%.The average mixing Angle increased and the average angular scale decreased significantly.The density of young trees in the lower layer showed a downward trend,but remained above 8000 /ha,with no significant changes in diversity index and herbaceous layer coverage.There was no significant difference in the physical and chemical properties of the soil except the quick effect P,and the content of the quick effect P was more than 40% lower than that of the control stand before the operation.The growth rate of the height fracture area of the reserved wood chest reached 8.89%,much higher than 1.99% of the same area.biomass increased by 16.89% on average.(2)Target tree management has an impact on the fine roots of dominant species such as castanopsis carlesii,castanopsis carlesii and forsythia formosana.The average root length,average diameter,SRL and SRA of the fine roots were all significantly different after the operation of the target tree,and the interaction of various tree species,tree species and treatments had an extremely significant or significant effect on the total C,total N content and C/N ratio of the fine roots.After 2 years of target tree operation,the content of N decreased by 39.36%,and the growth trend of castanopsis carlesii and Cyclobalano Psis glauca was observed.Castanopsis castanopsis and castanopsis castanopsis C content decreased to different degrees,while castanopsis castanopsis castanopsis content increased.The C/N ratio of castanopsis eyrei and castanopsis castanopsis castanopsis decreased and the content of formosana increased.(3)There was a weak correlation between fine roots and leaves of dominant tree species such as castanopsis carlesii,castanopsis castanopsis,and formosana.The N content of fine roots increased with the increase of the N content of leaves.P content was significantly correlated at the interspecific level,and the N:P ratio between leaves and fine roots was extremely significant among different species.There was a correlation between the proportion of nutrients absorbed and utilized by the leaves and the fine roots,and the specific leaf area and root length were correlated with the N level of the plant.SLA after logarithmic calculation was weakly correlated with SRL,and SLA and SRL were significantly different among different tree species.