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There are urgent calls for new approaches to map the global urban conditions of complexity, diffuseness, diversity, and connectivity. However, existing methods mostly focus on mapping urbanized areas as bio physical entities. Here, based on the continuum of urbanity framework, we developed an approach for cross-scale urbanity mapping from town to city and urban megaregion with different spatial resolutions using the Google Earth Engine. This approach was developed based on multi-source remote sensing data, Points of Interest – Open Street Map (POIs-OSM) big data, and the random forest regression model. This approach is scale-independent and revealed significant spatial variations in urbanity, underscoring differences in urbanization patterns across megaregions and between urban and rural areas. Urbanity was observed transcending traditional urban boundaries, diffusing into rural settlements within non-urban locales. The finding of urbanity in rural communities far from urban areas challenges the gradient theory of urban-rural development and distribution. By mapping livelihoods, lifestyles, and connectivity simultaneously, urbanity maps present a more comprehensive characterization of the complexity, diffuseness, diversity, and connectivity of urbanized areas than that by land cover or population density alone. It helps enhance the understanding of urbanization beyond biophysical form. This approach can provide a multifaceted understanding of urbanization, and thereby insights on urban and regional sustainability.

Segregation by racialized categories is common to cities across the world and its social effects are well studied. However, the environmental effects—the ecology of segregation—have received less attention. Racialized segregation persists through time and is associated with environmental hazards or lack of amenities. The environmental burdens of racial segregation are increasingly documented and this paper synthesizes the dynamics of segregation and the dynamics of ecological conditions associated with it. The ‘adaptive cycle of resilience,’ an important social–ecological theory, is applied and used to facilitate synthesis. The well-documented history of racial segregation in the US city of Baltimore, Maryland, is used to illustrate the systemic mechanisms that adapt segregation to changing social conditions, and hence maintain its ecological impacts. The adaptive cycle serves as a useful tool in evaluating and addressing the ecology of segregation and can thus advance urban ecology on a new horizon. Practice relevance The adaptive cycle of resilience demonstrates that persistent racial segregation in cities results from an intentional but flexible system that includes many seemingly banal practices. These include planning, zoning, patterns of investment, influence of the real estate industry, distribution of amenities and disamenities, and access to civic power and influence. The adaptive cycle shows that the persistence of segregation is not ‘natural’ or inevitable. Rather, segregation persists as a result of racialized policies and practices that exclude certain groups from civic goods and processes. Acknowledging that cycles of segregation have been, and are being, institutionally maintained identifies a system that may be disrupted by community action, policy adjustment, and planning practice.

Abstract Tree canopy cover is a critical component of the urban environment that supports ecosystem services at multiple spatial and temporal scales. Increasing tree canopy across a matrix of public and private land is challenging. As such, municipalities often plant trees along streets in public rights‐of‐way where there are fewer barriers to establishment, and composition and biomass of street trees are inextricably linked to human decisions, management, and care. In this study, we investigated the contributions of street trees to the broader urban forest, inclusive of tree canopy distributed across both public and private parcels in Baltimore, MD, USA. We assess how species composition, biodiversity, and biomass of street trees specifically augment the urban forest at local and citywide scales. Furthermore, we evaluate how street tree contributions to the urban forest vary with social and demographic characteristics of local residential communities. Our analyses demonstrate that street trees significantly enhanced citywide metrics of the urban forests' richness and tree biomass, adding an average six unique species per site. However, street tree contributions did not ameliorate low tree canopy locations, and more street tree biomass was generally aligned with higher urban forest cover. Furthermore, species richness, abundance, and biomass added by street trees were all positively related to local household income and population density. Our results corroborate previous findings that wealthier urban neighborhoods often have greater tree abundance and canopy cover and, additionally, suggest that investment in municipally managed street trees may be reinforcing inequities in distribution and function of the urban forest. This suggests a need for greater attention to where and why street tree plantings occur, what species are selected, and how planted tree survival is maintained by and for residents in different neighborhoods.