Planning and the High‐Rise Neighbourhood: Debates on Vertical Cities

This editorial introduces the thematic issue on “Vertical Cities: The Development of High‐Rise Neighbourhoods.” It outlines the lack of understanding about high‐rise development in cities around the world and argues for a continued need to fur‐ ther interrogate concepts of verticality beyond single towers and towards a finer grain examination of high‐rise neighbour‐ hoods. The editorial introduces four interconnected themes that begin to address this phenomenon—socio‐demographic challenges, planning discourses, high‐rise legacies, and alternative conceptions of verticality—and highlights how the var‐ ious articles in this thematic issue explore these critical areas of enquiry. It concludes with a call for future research to delve deeper into the planning challenges presented by high‐rise neighbourhoods in the 21st‐century city and, critically, the contribution that high‐rise urban form makes to urban sustainability.

Urban planners play a key role, not only in facilitating the design and development of these new vertical neighbourhoods but also in addressing and managing their variegated impacts on the built environment and the residents that live in and around them. There is, therefore, a need to problematise the socio-demographic issues present within vertical neighbourhoods, closely examine the planning processes that frame high-rise interventions in the built environment, examine how recent and historic decisions on the form, typology, location, and tenure of high-rise buildings and neighbourhoods impacts present day outcomes, as well as question the way verticality is understood in practice. This thematic issue seeks to advance these debates by drawing together articles exploring four key themes: socio-demographic challenges, planning discourses, highrise legacies, and alternative conceptions of verticality.

Socio-Demographic Challenges
Debates on vertical urbanisation have too often focused on the role of urban elites, middle and high-income purchasers, and real estate investors as the drivers of high-rise development. Yet, as Easthope et al.'s (2022) article argues, there is a necessity to recognise and plan for the needs of lower-income households in high-rise neighbourhoods. Drawing on a case study in Sydney, Australia, their article highlights the ways in which coordinated and collaborative planning processes can positively ensure the needs of lower-income households are met in highrise developments, while also emphasising how divergent political and market contexts can lead to different design and amenity outcomes for lower-income residents. Political and market factors are also at play in Grisdale and Walks' (2022) article, which explores how "condoization" has transformed Toronto's housing market and led to considerable structural changes in the rental market for high-rise apartments in the city. They argue that accepted conceptualizations of gentrification-as being driven by owner-occupied investment-need to be reconsidered given the socio-demographic composition of renters in gentrifying areas of the city. Critical perspectives on who occupies high-rise neighbourhoods is also the focus of Karsten's (2022) article, which advocates for new ways of thinking about inclusive vertical family housing. The article unpacks the "uneasy" relationship between young families and vertical living, focusing on the ways in which children have often been neglected in the planning and design of high-rise neighbourhoods. Yet, families have not stayed away from living in towers and, as Karsten argues, local governing authorities must acknowledge and better provide for this oftenoverlooked demographic. More research is needed on this topic, and as planning policy starts to catch up (e.g., City of Toronto, 2020), it must also confront wider socioeconomic forces that define new high-rise neighbourhoods as exclusive enclaves for young, childless renters.

Planning Discourses
The practice of urban planning cannot be detached from the wider socio-political context in which it takes place. Issues of governance regularly arise in contemporary planning processes as decision-makers, developers, residents, and other stakeholders engage in debates about the future of the built environment. High-rises, perhaps more than other forms of urban development, elicit strong reactions from all involved. As Herburger et al. (2022) highlight in their article exploring planning committees in Austria, Switzerland, and Germany, demands for and opposition against high-rise development have necessitated the creation of new governance processes. Their work offers particular insights on the ways in which the structural organisation of various planning committees, and their functions, act as state-led means of managing vertical urbanisation. Cerrada Morato's (2022) article delves deeper into the policy framework of Tower Hamlets in Greater London and the agency of planners within high-rise development processes. Cerrada Morato explores the influence of three planning policies designed to shape the outcomes of new vertical neighbourhoods and provides insights from planners on the effectiveness of these policies. The multi-scalar nature of planning policy within Greater London was found to constrain local planners' abilities to effectively influence the development of high-rise neighbourhoods as envisioned in policy. Along with London, the politics of vertical construction in Paris and Vienna are explored in Glauser's (2022) article through a "glocal" lens. Here the city-specific patterns of vertical development are identified as reflecting the precise urban politics present in each city, which define what is acceptable and what is to be rejected. The unique discourses present in each city frame the way high-rise developments are viewed and offer important lessons for comparative urban governance and planning-focused research on vertical urbanisation.

High-Rise Legacies
Many cities are experiencing a 21st-century revival of high-rise development but contemporary discourses on vertical urbanisation cannot be disconnected from the past. Altrock's (2022) article confronts the longestablished criticisms of mid-20th-century modernist high-rise development and reveals how this has influenced the design of contemporary projects in Germany. The "reconciliation" process between modern and post-modern urban design principles is used to explain the rise of "hybrid" ensemble urbanism in Germany and its relationship with wider global processes of vertical urbanisation. High-rise legacies not only influence current debates on the suitability of new towers, but they also present real challenges that impact how existing vertical neighbourhoods change (or do not change) to meet the contemporary demands of their owners/residents and the wider city. Hirai's (2022) exploration of "double ageing" addresses this legacy of high-rise development as he identifies the linked concerns of demographic ageing (residents) and physical ageing (high-rise towers). His article explores the considerable scale of double ageing in Tokyo's older high-rise developments and outlines the urgent need to address the growing generation gap between younger and older residents. The design and renovation of older high-rise developments also has implications for wider real estate markets and consumer preferences, as identified in Egedy et al.'s (2022) article. A former industrial district in Budapest is used to explore how the planning, architecture, and revitalisation of diverse post-war housing estates have impacted the housing market in different ways. While variations in desirability were found, the authors note how early socialist priorities articulated in the initial designs of structural attributes, neighbourhood characteristics, and location-now reversed in a market economy-nevertheless remain important to understanding the function of local real estate markets.

Alternative Conceptions of Verticality
The final set of articles in this thematic issue challenges us to think slightly differently about verticality by exploring high-rise development from a more intimate perspective beyond the realms of urban planning, urban design, and real estate markets. Mechlenborg (2022) draws attention to the role of social spaces in high-rise developments and the link between home, culture, and shared space. Through 50 semi-structured interviews, Mechlenborg argues that greater attention should be given to individuals and their social interpretations of home within research on vertical neighbourhoods, highlighting that designers and developers should first think horizontally about the need for and function of common areas, support facilities and social spaces before expanding vertically. March and Lehrer (2022) continue this line of thought in their article by focusing on the role and importance of public spaces within high-rise buildings during the height of the Covid-19 pandemic. Here they pay particular attention to tenant struggles and how the use of public spaces collided with wider concerns about public safety and ultimately resulted in the emergence of new publics and socially-produced public spaces. Everyday vertical living is made visible here as they highlight the "grey areas of publicness" (March & Lehrer, 2022, p. 360) and its interaction with wider aspects of vertical governance, public policy, and collective action. In contrast to the interior public spaces of high-rise buildings, Jin (2022) unpacks ideas on the exterior vertical terrain as a way of re-conceptualising urban verticality beyond high-rise development. Drawing on a case study of Chongqing in China, the article examines how terrain influences the design and function of the city. Here the vertical landscape has resulted in different ways of navigating the city and informed new ways of developing high-rise buildings and infrastructure that work with the mountainous terrain. This has generated a "mundane everyday verticality" (Jin, 2022, p. 374) that might be foreign to those familiar with horizontal ways of thinking about cities and surrounding environments.

Conclusions
The articles contained in this thematic issue reveal the breadth and depth of research on high-rise buildings and neighbourhoods both as a historical and contemporary phenomenon shaped by capital, context, and community. The past decade or so has seen unprecedented high-rise residential development in cities the world over. Yet, with the global economy faltering in the wake of the Covid-19 pandemic and the ongoing war in Ukraine, the demand for new high-rise development is likely to slow as the cost of borrowing for developers, investors, and owner occupiers alike increases. This presents researchers with an opportunity to reflect further on the vertical city in the early 21st century and to critically assess whether this complex and often controversial phenomenon is a sustainable urban fix in global cities or one that has failed to heed the difficult lessons learnt from the development of modernist vertical urban form in the mid-20th century. This thematic issue provides a series of new and engaging foundations for these future scholarly pursuits. James T. White is professor of planning and urban design in Urban Studies at the University of Glasgow, Scotland, and Deputy Director of the UK Collaborative Centre for Housing Evidence. His research focuses on the ways in which planning systems and real estate markets shape the design of cities. James has conducted research both in the UK and Canada. He has a particular interest in the form of high-rise buildings at the neighbourhood scale.