Studies On The Structure Of Urban Foerestry In Nanning

This paper mainly studied on the structure of urban forestry in Nanning, including: the number of the species in the research area; biology diversity in different types of urban forestry and their comparation; the characteristic of the size for the structure of the urban forestry in Nanning; the comparation of the leaf area index in different community; the interspecific association in 38 types of plants in shrub layer and so on. The results of the studyare:1 There are 89 sample plot, in the mass, we can see that the species of the urban forestry in Nanning is rich, there were 490species plants belonging to 325 genus and 121 families, including 29 species (belonging to 22 genus and 17 families) of Pteridophyte and 11 species (belonging to 8 genus and 6 families) of Gymnosperms and 450 species (belonging to 295 genus and 98 families) of Angiosperms. The proportion of the Angiosperms is great. There are 176 species plants (belonging to 134 genus and 62 families) of trees, the dominant of the arbor species is clear; and 282 species plants (belonging to 182 genus and 67 families) of shrub , they distribute uniformly.2 Based on the value importance in different communities, the biology diversity of the urban forest is studied by five indices, such as species richness, Shannon-Wiener index, Simpson index, PIE index, Pielou evenness index .The results indicate: (1)There were same variant tendency in diversity index and evenness index among tree layer, shrub layer and herb layer in different forest communities, and the diversity indices used in this paper all reflected the variation of plant communities of the urban forest in Nanning. (2)Among the different types of the urban forest in Nanning, the index's difference in tree layer and the shrub layer is clear, but in the herb it's not clear. The shrub's distribution is evenness, and the biodiversity of Nanhu is the lowest.In the mass we can see, that the biodiversity of the near-natural community and long-time built community is high, especially in shrub.3 The average diameter at breast height is small and the tree height is short. The health of...