Factors Influencing Australian Local Governments’ Street-Tree Species Selection

Abstract

Rapid urbanisation is resulting in environmental degradation, including soil erosion, species extinction, and air pollution. Street‐trees as part of a city’s green infrastructure have the potential to ameliorate some of these problems in urban environments. They can provide an array of services such as providing shade and habitat. Unfortunately, they can render disservices too, such as by damaging road surfaces, footpaths and underground infrastructure. The extent and type of street‐tree services and disservices vary among species. Hence, choosing the wrong tree for the wrong place can have significant social, economic, and environmental consequences. In 1997, Miller established a model that included parameters such as site factors, social factors, and economic factors to facilitate the process of selecting appropriate urban street‐tree species. However, globally and in Australia, there is limited research into how tree managers choose street‐trees. Surprisingly, the process of street‐tree selection, including how tree managers perceive tree costs and benefits is poorly understood. How tree managers weigh the different aspects of street‐trees when making planting decisions and developing tree lists for urban areas requires closer scholarly attention. This thesis examines the decision‐making principles of local government tree managers across Australia’s city councils. Consideration is given as to whether street‐tree selection criteria differ according to geographical location and climate. A mixed methods approach is used, including interviews, a questionnaire survey, and species analysis to understand the factors determining street‐tree species selection in Australian city councils.