Plant Species Diversity of Natural Secondary Forest Community in Northwest Zhejiang

The characteristics of the plant species diversity of natural secondary forest community in the northwest Zhejiang Province were studied. The plant growth form and the importance value of the community were determined, and the richness, evenness, and species diversity index of each layer of the community were calculated with varied calculation method. The results are as follows: (1) There existed the comparatively obvious dominant species within each layer of the natural secondary forest community, with Cyclobalanopsis glauca in tree layer, Cyclobalanopsis glauca and Loropetalum chinese in shrub layer and Indocalamus tessellatus in herb layer as the dominant species. (2) The natural secondary forest community in this area had rich plant species, with the species number of arbor tree being the most and that of the herb being the least. In terms of the layer of the natural secondary forest, the herb layer had the highest richness, followed by shrub layer and tree layer with a similar richness between them. The shrub layer had the highest evenness, followed by tree layer. While the richness of the herb layer was the lowest. Also, the shrub layer had the highest species diversity index calculated with various methods. The index for herb layer was the lowest even if it had the highest richness. (3) There were higher plant species diversity index and higher quantity index in the forest community which was closed for a longer time and suffered from less human disturbance.