This research examines the distributional equity of urban vegetation in 10 US urbanized areas using very high resolution land cover data and census data. Urban vegetation is characterized three ways in the analysis (mixed vegetation, woody vegetation, and public parks), to reflect the variable ecosystem services provided by different types of urban vegetation. Data are analyzed at the block group and census tract levels using Spearman’s correlations and spatial autoregressive models. There is a strong positive correlation between urban vegetation and higher education and income across most cities. Negative correlations between racialized minority status and urban vegetation are observed but are weaker and less common in multivariate analyses that include additional variables such as education, income, and population density. Park area is more equitably distributed than mixed and woody vegetation, although inequities exist across all cities and vegetation types. The study finds that education and income are most strongly associated with urban vegetation distribution but that various other factors contribute to patterns of urban vegetation distribution, with specific patterns of inequity varying by local context. These results highlight the importance of different urban vegetation measures and suggest potential solutions to the problem of urban green inequity. Cities can use our results to inform decision making focused on improving environmental justice in urban settings.
The majority of the world’s population lives in urbanized areas and urban populations continue to grow (United Nations, 2015). In North America, urbanization is particularly widespread, especially in Canada and the United States (US), where approximately 80% of the population lives in urban environments (McPhearson, Auch, & Alberti, 2013). As urbanization continues, urban vegetation, and the services it provides, are playing an increasingly important role in creating liveable urban spaces and helping to maintain the well-being of the majority of North American residents (Hansmann, Hug, & Seeland, 2007; Sanesi, Gallis, & Kasperidus, 2011). Urban vegetation provides important ecosystem services to urban residents. Mixed urban vegetation can reduce stormwater runoff via infiltration and evapotranspiration (McPherson, Simpson, Xiao, & Wu, 2011), and support a range of urban biodiversity (Goddard, Dougill, & Benton, 2009; Morimoto, 2011), while green views can reduce stress and improve psychological well-being (Kaplan, 2001; Tyrväinen et al., 2014; Ulrich et al., 1991). Woody vegetation, such as urban trees, can reduce the urban heat island effect via shading (Donovan & Butry, 2009; McPherson et al., 1997), improve air quality (Escobedo & Nowak, 2009; Nowak, Crane, & Stevens, 2006), sequester carbon (Nowak & Crane, 2002), and improve property values (Crompton, 2005), and may reduce crime rates (Troy, Grove, & O’Neil-Dunne, 2012). Urban parks offer opportunities for recreation that can improve physical health (Konijnendijk, Annerstedt, Nielsen, & Maruthaveeran, 2013; McCormack, Rock, Toohey, & Hignell, 2010) and increase social cohesion (Gehl, 2010; Kweon, Sullivan, & Wiley, 1998), and are often recreation destinations. As more and more people make cities their home, a case can be made that urban vegetation provides ecosystem services that influence the well-being of the majority of the world’s population. In light of this, societies should consider how best to ensure that all urban residents are able to benefit from these ecosystem services.