The Composition and Characteristics of Urban Plants and Tree Communities in Green Spaces Attached to Urban Roads, Beijing, China

摘要

In Beijing, the center of Chinese culture, politics and economic, greening construction was highly valued and the progress has been achieved in the field of landscape planting. As a main type of landscape green space, the green space attached to urbanroads plays an important role in functional, aesthetical and ecological use of urban greening. A survey of green spaces attached to urban roads was conducted during the period from September 2007 to April 2008, covering 35 urban roads of 3 different road section types. Forty six species/cultivars of landscape plants categorized into 25 families and 36 genera were recorded. Among trees, there were 14 kinds of deciduous trees and 6 kinds of evergreens, with a category ratio (deciduous species versus evergreens) of 2.3:1; of them, 7 quick-growing species/cultivars, 4 medium-growing ones and the remaining 3 slow-growing ones were found, with a category ratio of 2.3:1.3:1. And there were 8 kinds of deciduous shrubs and 6 kinds of evergreen ones, with a category ratio of 1.3:1. Furthermore, 7 kinds of perennials, 4 kinds of annuals and biennials and 1 kind of bamboo were recorded. Some 47.8% of the plant population was contributed by 22 native species, 10.9% (5 species) were introduced from other parts ofChina and 26.1% (12 species) were introduced from overseas. Of the 46 urban road plant species, only 9 were planted in all three landscape road section types (trilanscape). Six types were identified in vertical structure of the typical tree community in35 sample roads. The analysis reveals urban road landscape planting problems in Beijing such as low biodiversity, improper tree community structure and low internal variability and high affinity to each other. Knowledge on plant species composition and characteristics of tree patterns will be of great value not only for improving streetscape and roadside environmental quality, but also for green spaces attached to urban roads as well as the urban green-space planning from ecological and phytosociological viewpoint.