Résumé : In the last decades the population living in cities has substantially increased. According to the United Nations, by 2050 two thirds of the world population will be living in urban areas. Demographic pressure, through influx of residents or internal growth results in expansion and densification of urban areas and goes hand in hand with increased imperviousness, putting pressure on the provision of urban green. Urban green offers a range of direct and indirect benefits to the urban ecosystem. Green in the city reduces rainwater runoff and flooding risk while improving water quality; it improves air quality, provides natural cooling and contributes to reducing the urban heat island effect. Being the main source of contact with nature, urban green has also been shown to contribute to the physical and psychological wellbeing of urban citizens. The environmental concern for urban nature and re-naturing of cities are thus at the heart of developing more «ecological approaches to sustainable urban design and planning». In the framework of this research, it implies: understanding the (spatial) distribution of green space in relation to the built-up area of the city at different scale levels – the benefits they provide, their quality and proximity for urban residents – and; how to develop diagnostic, analytical and projective capabilities aimed at improving their (urban green) provision to address a host of sustainability challenges related to climate change, demographic growth and densification of the urban area. The research focuses on the development of evidence-based frameworks for planning that incorporate citizens’ needs and that are built on an interdisciplinary foundation. With this scope and focus, this study contributes to the development of a more ecological framework for sustainable urban design and planning aimed at integrating nature in the city more effectively and in an evidence-based way. The first part of the research focuses on the development of a spatially explicit tool for green space quality and proximity assessment reflecting user’s perception. Application of the model in the Brussels context reveals that user’s perception of qualities of urban green spaces such as naturalness and spaciousness can be linked to green space characteristics as described by available GIS-based data. As such GIS-based modelling allows for an extrapolation of questionnaire-based quality assessments for a selection of parks to other public green spaces. Analysis of the proximity of urban green spaces based on user’s perception shows spatial inequalities in green space provision, with less than 50% of Brussels’ citizens having good access to small (residential and play green) and to large green spaces (city and metropolitan green). By coupling multi-scale proximity assessment with quality assessment of green spaces, it is demonstrated that nearly two third of the Brussels population has no access to high quality public green spaces. Through collaborative research by design workshops involving different stakeholders, indicators produced by the quality-proximity model are used to indicate and tackle problem areas. Three alternative scenarios for public green space development are defined. The scenario analysis demonstrates that actions to provide low-income neighborhoods with a good accessibility to public green spaces will require creative solutions, dealing with complex property and management issues, and levels of investment that go well beyond the cost of regular green space development. The second part of the study presents a GIS- and design-based approach to assess potential land cover change for the Brussels-Capital Region anticipating expected population growth. The methodology proposed can be used to assess the impact of spatial policies and the implementation of building codes on future urban land cover. By studying the everyday processes for parcel infill and densification, and by defining a densification process based on the principles of sustainable urban design (e.g., walkable and high-density urban areas near mobility hubs, compact building typologies, preserving valuable natural areas, creative approaches to increasing the provision of urban green (green roofs, bioswales, etc.) space for water and floodscapes, etc.), two land use evolution scenarios are formulated; a business-as-usual and a sustainable scenario. One of the main conclusions of the case study on the Brussels-Capital Region is that densification can be deployed as a vehicle for positive land cover change and greening of the city.