A choice-based conjoint analysis of public preferences on urban tree attributes in Shanghai, China

Abstract

Urban parks play a vital role in urban ecosystems by providing a wide range of ecosystem services and amenities. Trees, as a critical element of park design, contribute to the function of urban parks, especially in the aesthetic and ecological functions. With the acceleration progress of urbanization and urban environmental problems, selection of trees is important for making the urban ecosystem healthy and for residents needs to be met. Urban greening is one of policies which has been emphasized for realization of ecological civilization in China. This research applied choice-based conjoint analysis to investigate public preferences on different attributes of urban tree species in Shanghai. In addition, the study tries to find out if there is any preference heterogeneity in tree attributes by the social-economic characteristics of Shanghai citizens. A pretest was conducted to select important attributes of trees in advance. The six attributes, namely shape of canopy, seasonal change of leaf, carbon sequestration, cooling and humidity, reducing dust and capacity to enhance biodiversity were selected. A survey was conducted in Shanghai city in China with a total valid sample size of 421. The result shows that, among the 6 attributes selected, shape of canopy, seasonal dynamics of leaf, carbon sequestration and dust absorption capacity are found to be more influential in the publics welfare. Canopy round shape rather than oval or weeping canopy is more preferred by the Shanghai public. Meanwhile, residents in Shanghai are more concerned about carbon fixation and dust absorption function of trees in urban parks. This is probably because the global warming issue becomes more awared and air pollution becomes more serious in recent years in China. This result is considered to reflect the fact that air quality problem has become a great concern to the public in urban areas in China. Therefore, the author suggests that in designing of urban parks, trees should be selected so as to enhance the public environment for the health and global environment. This study also revealed the differences in preference of the citizens social-economic characteristics. Old people more favor the cooling and humidification function of urban trees, while less favor carbon sequestration function.