Dynamics Anasysis And Affecting Factors Of Sprout Regeneration Of Evergreen Broad-leaved Forest In Gutianshan

As an important regeneration strategy of forest tree species,sprout regeneration had far-reaching influence and significance on the maintenance of community diversity,regeneration dynamics and population continuation,but the process change and driving factors of forest community sprout regeneration had not been deeply understood.Sprout regeneration was common in subtropical evergreen broad-leaved forest.How did its sprouting characteristics and sprouting ability change with forest community regeneration? What were the influencing factors of sprouting and renewing changes? This paper made a statistical analysis based on the two recheck data of 5ha evergreen broad-leaved forest in Gutian Mountain,Zhejiang Province from 2012 to 2017,and explored the changes of sprouting species composition and sprout regeneration in the sample plots,as well as the influencing factors of sprout regeneration(including community diversity,topography and interspecific competition).This study was helpful to deepen the understanding of the process of sprout regeneration of evergreen broad-leaved forest in Gutian Mountain,and to understand the influencing factors of sprout regeneration of evergreen broad-leaved forest in the middle subtropics.and provided a theoretical basis for systematically discussing the status of sprout regeneration in the mid-subtropical forest community.The main results and conclusions were as follows:(1)A total of 117 sprouting species were found in Gutian Mountain 5ha plot from 2012 to 2017,of which 2017 decreased 2 families,3 genera and 3 species compared with 2012,but the number of sprouting plants(sprouting individuals)increased by 585.In the past five years,the families,genera and species with the dominant number of sprouting individuals basically did not change,but the proportion increased or decreased to a certain extent,and the order changed.From different functional groups,there were always more sprouting individuals of evergreen trees than deciduous trees from 2012 to 2017,while sprouting individuals of small shrubs were always more than trees,shrubs or small trees.(2)T-test was used to analyze the sprouting ability of species,community and different functional groups in the sample plot from 2012 to 2017.It was found that at the species level,the difference of sprouting ability in five years was not significant,while in the community level,the sprouting ability in 2017 was significantly higher than that in 2012.In terms of different life forms,the sprouting ability of evergreen groups in 2017 was significantly higher than that in 2012,while the sprouting ability of deciduous groups had no significant difference in five years.In terms of different growth forms,the sprouting ability of small shrubs in 2017 was significantly higher than that in 2012,and that of shrubs or small trees in 2017 was significantly higher than that in 2012.The results showed that in the sample plot of evergreen broad-leaved forest from 2012 to 2017,the sprouting ability of community level gradually became stronger with the passage of time,while the sprouting ability of species changed little,and there was no obvious difference.Due to the different species composition,the sprouting ability of different functional groups was also different,in which the sprouting ability of evergreen group,small shrub group,shrub or small tree group increased significantly,but the sprouting ability of deciduous group and tree group basically did not change.(3)Through simple linear regression and multiple regression model,the correlation between influencing factors and sprouting ability of community level,evergreen group,small shrub group and shrub or small tree group was analyzed.It was found that the change value of Simpson index,Shannon-Wiener index,plant density and basal area were negatively correlated with the change of community sprouting ability.The initial(2012)of Simpson index,Shannon-Wiener index,Pielou evenness index were positively correlated with the change of sprouting ability of small shrubs,and the species richness change was positively correlated with the change of sprouting ability of shrubs or small trees.The results showed that in the 5ha plots of evergreen broad-leaved forest in Gutian Mountain,the sprouting ability of community level decreased with the increase of community diversity and interspecific competition,and the initial community diversity affected the sprouting ability of small shrubs.In the communities with relatively abundant initial species,the sprouting ability of small shrubs was stronger,and the sprouting ability of shrubs or small trees decreased with the increase of community species richness.Topographic factors could have an effect on sprout regeneration by affecting community diversity,but there is no correlation between topographic factors and the change value of sprouting ability.In summary,this study found that the community sprouting ability of 5ha evergreen broad-leaved forest in Gutian Mountain is constantly changing with the passage of time,and the change rules of sprouting ability of different functional groups are different.Community diversity and community competition have a certain impact on the change of sprouting ability.The study on the change law of sprouting regeneration and its influencing factors is helpful to deepen the understanding of the process of sprouting and regeneration of zonal vegetation in this area,and provide reference data for subtropical forest regeneration and woodland restoration;the follow-up research on the process of sprouting regeneration and its influencing factors can be combined with soil,climate and other influencing factors,and select a variety of community types with larger sample plot scale and longer time scale to carry out systematic discussion.