Studies On Community Characters Of Two Typical Broad-leaved Forest Of The Hilly Area In Central Of Hunan Province

In recent years, many scholars found that subtropical forest vegetations were being degraded in China. The central hilly area of Hunan Province is a part of the subtropical regions in China, at present, very few people had study the community characteristics of broad-leaved forest community in the central hilly area of Hunan Province. In this study, we had investigated two types of broad-leaved forest community characteristics in Dashanchong forest park. In order to understand the broad-leaved forest community characteristics composition and renewal condition in the central hilly area of Hunan Province, to discuss the distribution pattern of dominant population in community, to provide theoretical of protection, management, ecological function and the development and succession about the central hilly area of Hunan Province. It will provide guidance of ecosystem restoration and reconstruction.We had set two plots about deciduous broad-leaved forest community and evergreen broad-leaved forest community in Dashanchong forest park, the size of plot is100m*100m. We had investigated and recorded the species, diameter at breast height, tree height, crown breadth, first live branches high and location of every plant.After analysis of investigate recorded data and research, the results showed:(1) Choerospondias axillaries and Lithocarpus glaber are the dominant tree species in deciduous broad-leaved forest and evergreen broad-leaved forest community respectively. A total of82species, belong to35families and59genera. Fagaceae, Theaceae, Lauraceae are the main families in two communities. Vegetation is mainly dicotyledonous plants, there are36evergreen species and46deciduous species. The number of species in tree layer is much more than shrub and herb layers. Species diversity of evergreen broad-leaved forest community is better than deciduous broad-leaved forest community.(2) By analyzing the species diversity, we found that the plant species is rich, stand density is large, Species distribution is evenly and dominant species is obvious.The top five of important values in deciduous broad-leaved forest community were Choerospondias axillaries, Symplocos setchuensis, Eurya muricata, Vernicia montana and Litsea coreana. In evergreen broad-leaved forest community were Lithocarpus glaber, Cyclobalanopsis glauca, Cleyera japonica, Pinus massoniana, and Choerospondias axillaries.(3)The Areal-types of most species in the central hilly area of Hunan Province were Pantropic, followed by Trop.&Subtr. E. Asia&(S.) Trop. Amer. Disjuncted.(4) The diameter structure of the communities showed an inverted J curve type, means the number of young trees is more than the elders. The diameter structure of Symplocos setchuensis, Eurya muricata, Litsea coreana in deciduous broad-leaved forest community and Lithocarpus glaber, Cyclobalanopsis glauca, Cleyera japonica in evergreen broad-leaved forest community were also showing an inverted J curve. Evergreen trees showing a good development trend in communities. But the diameter structure of Choerospondias axillaries in deciduous broad-leaved forest community and Pinus massoniana in evergreen broad-leaved forest community showed normal distribution, it means the two species has grown to an advanced stage.(5)the number of species in high layer is less than the low layer. The dominant tree species had a big proportion in the high layer. In the low layer, the number of evergreen tree species is more than the deciduous tree species. Choerospondias axillaries in deciduous broad-leaved forest community are mainly distributed in the high forest layer, a few in the low layers. In the evergreen broad-leaved forest community, Lithocarpus glaber and Cyclobalanopsis glauca were distributed in every forest layer, and mainly in the low forest layer. Choerospondias axillaries and Pinus massoniana were mainly distributed in high forest layer.(6) The regeneration of evergreen tree species, such as Symplocos setchuensis, Eurya muricata, Cyclobalanopsis glauca, Cleyera japonica and Lithocarpus glaber were very good, had a large number of seedlings. But the regeneration of deciduous tree species like Choerospondias axillaries and Pinus massoniana was deficient, seedlings is inadequate. It will affect the competitiveness of species in the community.Choerospondias axillaries in deciduous broad-leaved forest seedlings is shortage, its dominance will gradually decline over time. Pinus massoniana in evergreen broad-leaved forest also has the same situation. Lithocarpus glaber, Cyclobalanopsis glauca, Symplocos setchuensis and Eurya muricata have a great advantage-ment in the community; the number in each layer is coherent and prominent. The dominant position of evergreen broad-leaved forest community was rising. The broad-leaved forest community in the central hilly area of Hunan Province will directed to the evergreen broad-leaved forest in succession.