Studies On The Characteristics Of Plant Communities In Shanghai New Green Spaces

The research was conducted by the method of combining field survey with collections of forestation projects to study the characteristics of plant communities in Shanghai newly built green spaces, among of which 87 uptowns, 26 road and public areas, 54 organization areas and 26 factory areas were selected as the research objects. The analysis of plant composition and the distributions of size class and height as well as the characteristics of uptown green spaces in different districts presented that: Species in uptown is more than that in the other three types, on the contrary, Species in factory area is the least. There is a lack of Liana and bamboo and local species. Dominant species among arbors are Cinnamomum camphora , Zelkova schnideriana, Ginkgo biloba, Magnolia grandiflora in uptowns, Cinnamomum camphora, Cerasus serrulata in organization areas, Cinnamomum camphora, Magnolia grandiflora, Ginkgo biloba, Ligustrum lucidum, Metasequoia glyptostrodoides in road and public areas and Cinnamomum camphora, Prunus persica, Metasequoia glyptostrodoides, Elaeocarpus sylvestris, Ligustrum lucidum, Cerasus serrulata in factory areas respectly. Compared with arbors, dominant species among shrubs are between 7 and 9 and Cynodon dactylon dominated among all herbs in the four types, further more , the amount shrubs are far more than the amount of arbors, especially in the uptowns.There are many differences in the distribution of size class as well as the height distribution in different types. The curve of size class distribution in uptowns goes up and then declines while it goes down gradually in the other three types with the increase of size class; the curve of height distribution in factory areas goes down gradually while it goes up and then declines in other three types with the increase of height . Most species are among the size class of 5～10cm and the height grade of 5~7m, the average diameter of trees in uptowns, organization areas, road and public areas and factory areas are 10cm, 5cm, 6cm, 5cm and the average height are 5m, 5m, 5m and 4m respectively , which shows that trees are low and small. Concretely speaking, trees in uptowns are mainly in the height grade of 5～7m,trees in factory areas are mostly in the grade of 3m and a majority of trees in the other two types are in the grade of 3～5m. the distribution of size class in uptown is comparatively good, trees in the size of 5～10cm are in a great measure while the size class of most trees are only below 5cm in the other three types.The ratio of deciduous trees, evergreen shrubs and the quantity of arbors in outskirt and the area between outskirt and center are a little higher than ratios in the center of the city, the frequency and quantity of arbors, shrubs, herbs, liana and bamboo in common use are not same in different areas. And species are very much alike ,which led to many similar green spaces though those spaces have different function or in different area etc.The average diameter of trees in the center, area between center and outskirt, outskirt are 10cm, 11cm, 9cm and the average height are 5.1m, 5.7m, 5.6m respectively , which shows that trees are higher and larger in area between center and outskirt. In addition, the characteristics of plant communities are also influenced by the scale of green spaces and the investment of forestation project and other factors like ideas and abilities of designers.At the end of the thesis a deep discussion was made according the results of this research.