Differences In Species Composition And Soil Properties During Conversion In An Evergreen Broad-leaved Forest

In the process of forest conversion,species and soils of different forest types also change,but there are few studies on the difference of species composition and soil properties in Evergreen Broad-leaved Forest.In order to deepen the understanding of different forest types in the process of evergreen broad-leaved forest conversion,we selected Cunninghamia lanceolata Forest,Phyllostachys heterocycla Forest,Coniferous Broad-leaved Forest,Evergreen Deciduous Broad-leaved Forest,Evergreen Broad-leaved Forest and dominant tree species of Cunninghamia lanceolat,Phyllostachys heterocycla,Alniphyllum fortunei,Schima superba and Castanopsis eyrei were selected as the research objects in Guanshan National Nature Reserve of Jiangxi Province,The diversity characteristics of trees,shrubs and herbs in each forest type were analyzed,and the soil properties and root traits of dominant tree species were also measured.Finally,the differences among different forest types in the conversion process were explained from the perspective of species,soil and root.The main results are as follows:(1)There were differences in species composition among different forest types.The number of species(38)and Shannon index(2.35)in Evergreen Deciduous Broad-leaved Forest were the largest,followed by Evergreen Broad-leaved Forest(26,2.14),Cunninghamia lanceolat Forest was the lowest(9,1.34).In shrub layer and herb layer,the species number of Cunninghamia lanceolat Forest was the highest(39,29),while that of Evergreen Broad-leaved Forest was the lowest(24,16).Shannon index of Cunninghamia lanceolat Forest was the highest(2.96,2.94),while that of Evergreen Broad-leaved Forest was the lowest(2.51,2.63).(2)In terms of individual plant,the highest total specific surface area of fine roots of Castanopsis eyrei was 148.01 cm~2/g,followed by Schima superba 112.98 cm~2/g,and Cunninghamia lanceolata 85.33 cm~2/g.The highest total specific root length of Castanopsis eyrei was 5.89 m/g,followed by Schima superba 5.05 m/g,and Cunninghamia lanceolata3.06 m/g.(3)Soil physical and chemical properties and soil enzyme activities varied greatly among different forest types.The soil enzyme index showed as follows:Evergreen Deciduous Broad-leaved Forest(0.51),Evergreen Broad-leaved Forest(0.42),Phyllostachys heterocycla Forest(0.35),Coniferous Broad-leaved Forest(0.29),Cunninghamia lanceolata Forest(0.21).The comprehensive index of soil nutrient pool was1.99 in Evergreen Deciduous Broad-leaved Forest,followed by Evergreen Broad-leaved Forest(1.86),and 1.44 in Cunninghamia lanceolata Forest.The highest comprehensive score of soil fertility quality in 0～10cm soil layer of Evergreen Deciduous Broad-leaved Forest was 7.674.Soil physical and chemical indexes were correlated with root characters and soil enzyme activities.The above results show that the Guanshan National Nature Reserve of Jiangxi Province reserve exist obvious differences between different forest types,in the process of conversion of forest and natural protection,most abundant tree species of Evergreen Deciduous Broad-leaved Forest,soil physical and chemical properties and soil enzyme activity most conducive to the growth of plants,Castanopsis eyrei and Schima superb of fine root traits more advantages than other tree species of fine root.Therefore,in the process of forest conversion,we can promote the conversion of secondary forest to Evergreen Deciduous Broad-leaved Forest by adjusting the species composition within the forest to achieve better ecological function.