Redlining was a racially discriminatory housing policy established by the federal government’s Home Owners’ Loan Corporation (HOLC) during the 1930s. For decades, redlining limited access to homeownership and wealth creation among racial minorities, contributing to a host of adverse social outcomes, including high unemployment, poverty, and residential vacancy, that persist today. While the multigenerational socioeconomic impacts of redlining are increasingly understood, the impacts on urban environments and ecosystems remain unclear. To begin to address this gap, we investigated how the HOLC policy administered 80 years ago may relate to present-day tree canopy at the neighborhood level. Urban trees provide many ecosystem services, mitigate the urban heat island effect, and may improve quality of life in cities. In our prior research in Baltimore, MD, we discovered that redlining policy influenced the location and allocation of trees and parks. Our analysis of 37 metropolitan areas here shows that areas formerly graded D, which were mostly inhabited by racial and ethnic minorities, have on average ~23% tree canopy cover today. Areas formerly graded A, characterized by U.S.-born white populations living in newer housing stock, had nearly twice as much tree canopy (~43%). Results are consistent across small and large metropolitan regions. The ranking system used by Home Owners’ Loan Corporation to assess loan risk in the 1930s parallels the rank order of average percent tree canopy cover today.

As highly managed ecosystems, urban areas should reflect the social characteristics of their managers, who are primarily residents. Since landscape features develop over time, we hypothesize that present-day vegetation should also reflect social characteristics of past residents. Using an urban-to-suburban watershed in the Baltimore Metropolitan Region, this paper examines the relationship between demographics, housing characteristics, and lifestyle clusters from 1960 and 2000 with areas of high woody and herbaceous vegetation cover in 1999. We find that 1960 demographics and age of housing are better predictors of high woody or tree coverage in 1999 than demographics and housing characteristics from 2000. Key variables from 1960 are percent in professional occupations (+), percent of pre-WWI housing (−), percent of post-WWII housing (+), and population density (−). Past and present demographic and housing variables are poor predictors of high herbaceous cover in 1999. Lifestyle clusters for 2000 are very good predictors of high herbaceous coverage in 1999, but lifestyle clusters from 1960 and 2000 are poor predictors of high woody vegetation coverage. These findings suggest that herbaceous or grassy areas, typically lawns, are good reflections of contemporary lifestyle characteristics of residents while neighborhoods with heavy tree canopies have largely inherited the preferred landscapes of past residents and communities. Biological growth time scales of trees and woody vegetation means that such vegetation may outlast the original inhabitants who designed, purchased, and planted them. The landscapes we see today are therefore legacies of past consumption patterns.

There is a growing recognition that responding to climate change necessitates urban adaptation. We sketch a transdisciplinary research effort, arguing that actionable research on urban adaptation needs to recognize the nature of cities as social networks embedded in physical space. Given the pace, scale and socioeconomic outcomes of urbanization in the Global South, the specificities and history of its cities must be central to the study of how well-known agglomeration effects can facilitate adaptation. The proposed effort calls for the co-creation of knowledge involving scientists and stakeholders, especially those historically excluded from the design and implementation of urban development policies.

Urgent sustainability challenges require effective leadership for inter- and trans-disciplinary (ITD) institutions. Based on the diverse experiences of 20 ITD institutional leaders and specific case studies, this article distills key lessons learned from multiple pathways to building successful programs. The lessons reflect both the successes and failures our group has experienced, to suggest how to cultivate appropriate and effective leadership, and generate the resources necessary for leading ITD programs. We present two contrasting pathways toward ITD organizations: one is to establish a new organization and the other is to merge existing organizations. We illustrate how both benefit from a real-world focus, with multiple examples of trajectories of ITD organizations. Our diverse international experiences demonstrate ways to cultivate appropriate leadership qualities and skills, especially the ability to create and foster vision beyond the status quo; collaborative leadership and partnerships; shared culture; communications to multiple audiences; appropriate monitoring and evaluation; and perseverance. We identified five kinds of resources for success: (1) intellectual resources; (2) institutional policies; (3) financial resources; (4) physical infrastructure; and (5) governing boards. We provide illustrations based on our extensive experience in supporting success and learning from failure, and provide a framework that articulates the major facets of leadership in inter- and trans-disciplinary organizations: learning, supporting, sharing, and training.

This paper presents initial findings from longer-term transdisciplinary research concerning the social dynamics of urban neighbourhoods. It examines the spatial clustering of ethnicity and class in neighbourhoods over urban history, from Bronze Age Mesopotamia to contemporary cities. Fourteen distinct drivers of social clustering are identified, grouped under the headers of macro-structural forces, the state, local regimes and institutions, and bottom–up processes. The operation of these processes is examined through three historical and three archaeological case studies of clustering. It is concluded that: clustering is a common, but not universal, attribute of cities; there is much variation in clustering patterns, both within and between cities and urban traditions; and, consideration of a wide variety of drivers is required to understand historical and modern residential dynamics.