Combining insights from urban design theory and political philosophy, this research aims to bridge the gap between public and private spaces in cities. While existing approaches to urban design have successfully enhanced social cohesion at the street level, they fail to address the potential of spaces within and on top of buildings.

This thesis proposes a cross-disciplinary framework for embedding semi-public functions in and around high-rise developments, functions that invite social interaction, inclusivity, and civic presence in the vertical dimension of the city. By integrating perspectives from Urban Management, Urban Planning, and Urban Design, the research addresses both conceptual and operational barriers that inhibit the vertical expansion of public life.

Achieving this ambition requires a shift in how ownership, access, and publicness are understood, alongside practical tools to navigate legal complexities and spatial hierarchies. Through spatial design strategies and organisational models, the research demonstrates how elevated spaces can become legible, accessible, and socially meaningful extensions of the urban commons.

This research introduces The Forest of the Future, a transformative visionary that reimagines European forests as multifunctional, sustainable spatial structures extending over land and sea. It confronts current environmental challenges, including deforestation, biodiversity loss, and climate change, by proposing an innovative spatial strategy for the BeNeLux bioregion within a broader European context. The strategy aims to integrate forestation within other land uses enhancing ecological, social, and economic values towards a sustainable future by 2100. Based on conceptual frameworking and a multi-criteria decision analysis, it evaluates current land use, soil quality, climate zones, biodiversity, and the state of marine environments, proposing new forest types and forestry-based regenerative agricultural practices. The envisioned forest network serves not just as a carbon sink but as a catalyst for biodiversity, sustainable agriculture, and community well-being.

Achieving this transition requires a multifaceted approach, including policy reform, stakeholder engagement, and the development of a strategic implementation plan that aligns with regional and European sustainability goals. This strategy requires a combination of regulating, stimulating, engaging and capacity building instruments, Additionally, the transition to a forest-based land use system requires a combination of policies tailored to ‘planting the seeds’ in the near future, launching the Future Forest, and ones ensuring the healthy maturation of those ecosystems over the following decades. The research concludes with an evaluation of potential impacts on greenhouse gas emissions, suggesting significant contributions towards Europe’s climate goals of climate neutrality.