Community Structure And Leaf Characteristics Of A Secondary Broadleaved Forest In Hilly Area Of Central Hunan, China

The broad-leaf forest community of the hilly area of central Hunan belongs to the Subtropical evergreen broadleaved forest region according to the"Chinese vegetation districts", but most become secondary or plantation due to the influence of human activities. Plant species in the hilly area of central Hunan secondary broadleaf forest are plentiful, the forest structure is complex.In order to discuss the Species composition and community structure,we set a 1.0 hm2 sample plot in Da-Shan-Chong forest park of ChangSha in Hunan province, in the 10000 m2 survey rectangular plot, there are 1864 trees with DBH greater than 4 cm, belonging to 73 species. The Margalef species richness index of the community was 5.81, Shannon-Wiener diversity index was 2.53, and Pielou evenness index was 0.59. The results indicated that the hilly area of central Hunan broadleaf forest community showed rich but not evenness floristic composition. Group each species has obvious differences between individual numbers, community species is richer, more focused on more than 10 kinds of degree. The dominated species are Lithocarpus glaber, Cyclobalanopsis glauca, Pinus massoniana, Choerospondias axillaris, Cunninghamia lanceolata, Liquidambar formosana, Quercus fabri and Litsea coreana; the shrub layer was mainly dominated by Ilex purpurea, Oropetalum chinensis,Eurya muricata, and Symplocos caudata et al. The number and breast-cut-area of 8 dominated tree species in the broad-leaved forest are accounted for all the 70.12% and examining wood 79.07%, mainly determines the structure and forest community succession tendency.A reverse-J shaped DBH classes distribution was observed for all stems and trees of later serial species while trees of earlier successional species distributed irregularly. The structures of the height distribution were normal-left distribution for the stand and its main dominant populations of the hilly area of central Hunan broadleaf forest community, and indirectly indicated that both intra-and inter-specific competitions were exist for light resources.The research on leaf characteristics and seed dry weight of eight superiority species and 4 representative shrubs species in the study sample found that:Specific leaf area and SPAD differed significantly among the 12 tree species. The highest SLA was found for deciduous broadleaved tree species, and the lowest for, conifers, broad-leaved evergreen tree species and shrubs had the intermediate SLA. For SPAD, broad-leaved shrubs had the highest value, followed by evergreen broad-leaved tree species, and deciduous tree species had the lowest values. SLA changed significantly with canopy position, but no significant was observed for SPAD at different canopy position. Among 12 tree species, SLA of L. formosana and L. glabra showed insignificant difference with canopy position, SLA of P. massoniana increased significantly but the other 9 tree species declined significantly with canopy position. Seed mass decreased in the order of C. axillaries, C. glauca, L. glabra, O. chinensis, L. coreana, C. anceolata, E. muricata dunn. There was no significant correlation between SLA and SPAD for shrub, but significant negative correlation for broadleaved trees. Seed mass did not relate to SLA and SPAD for all tree species.