Effects Of Different Cutting Periods And Cutting Intensities On Community Structure Of Broad-leaved Korean Pine Forest In Jiaohe,Jilin

The temperate forests in Northeast China are one of the most important types of forests in my country Due to global climate change and human activities,the sustainable development of temperate forests in Northeast China is under threat.In this study,through the investigation of broad-leaved Korean pine forest in Jilin Jiaohe and the processing and analysis of indoor data,the basic research principles and methods of botany and ecology were used to investigate the different restoration periods of Jiaohe in Jilin(10 years,20 years,30 yeats,40 years,50 years)And the restoration dynamics and restoration characteristics of broad-leaved Korean pine forest communities with different logging intensities(control,light thinning,medium thinning,heavy thinning),and aims to provide a theoretical basis for the protection of Jiaohe broad-leaved Korean pine forest in Jilin.Research indicates(1)There are 109 species of plants belonging to 74 genera and 46 families in Jiaohe broad-leaved Korean pine forest community in Jiaohe Jilin.Among them,there are 4 families,5 genera and 5 species of ferns.1 family,3 genera and 4 species of gymnosperms.Single family,single genus and single species phenomenon is remarkable.With the increase of recovery time and cutting intensity,the species composition of the tree layer changes little,and the dominant degree of the main tree species increases In contrast,the species composition of the understory shrub layer and the herb layer changes greatly,and the important value of the dominant species in the shrub layer was decrease,and the important value of the dominant species in the herb layer showed no obvious change trend with the increase of recovery time,but the important value decreased with the increase of cutting intensity.The species diversity of the community increased with the recovery time,and the logging disturbance promoted the increase of the forest diversity,and the MT forest has the largest species diversity among logging disturbance forests(2)After 50 years of restoration,the diameter-level structure of the forest stands showed a nearly bimodal distribution,and the rest of the forest stands have an inverted " J" type distribution.The important value of the individual groups in the small-diameter group(1≤DBH ≤10cm)decreases first and then rises with the increase of recovery time,and increases with the increase of cutting intensity;the important value of the individual group in the middle-large diameter group(DBH≥35cm)increases first and then decreases with the increase of the recovery time and cutting intensity.With the increase of recovery time,the community structure is more stable,and the logging disturbance has an impact on the community structure,of which the medium thinning improvement effect is better(3)There is a certain correlation between the community structure and species diversity.RDA analysis and Monte Carlo test show that the "Tree high Shannon index" is the main structures index that affect species diversity in the forest stands at different restoration periods,among the stands of different logging intensities,the "DBH Shannon index" has the greatest impact on species diversity(4)From the restoration of 10 years of forest to the restoration of 40 years of forest,as the restoration time increases,the aboveground biomass of the forest increases,and logging reduces the aboveground biomass in the short term.Community structure is one of the important factors that affect the aboveground biomass of forest stands,RDA analysis and Monte Carlo test show that the "average diameter" has the greatest impact on the aboveground biomass of forest stands in different restoration periods,and the "DBH Shannon index " and " DBH Eveness index " have the greatest impact on the aboveground biomass of forests with different logging intensities.