Street Trees Across Culture and Climate : A Comparative Analysis of Density and Distribution

Abstract: The positive relationship between humans and nature is manifest in the urban greening movement, which has taken root in cities around the world. Street trees are an essential component of urban design and have emerged from a variety of historic legacies, both human and environmental. While the growing body of research on street trees has considered street tree density and distribution across cities, it has not situated these metrics in the broader discussion on the historical legacies of urban greening. This study considers five capital cities (Ottawa, Stockholm, Buenos Aires, Paris, and Washington, D.C.) spanning two climate zones and three continents to analyze the density and distribution of street trees by asking two questions: (1) what is the density and distribution of street trees across a given city and its street hierarchy? (2) how do these metrics compare within and between cities by climate zone? Preexisting datasets from local authorities are used to execute a geospatial analysis of the street tree structure of the central zone of each city. The results of this study shed light on the importance of place-specificity in informing the street tree legacy of cities and questions the existing primacy of the city-wide canopy cover metric as a global norm in planning practice.