Boundary as space. The definition of the boundary for the architectural and urban design of green spaces.

This paper will investigate the issue of limits for the architectural and urban design of green and safe spaces within cities. While increasing green areas has great advantages in improving the quality of urban space and coping with significant climate and energy crises, it remains an open question as to how these spaces deal with long-established urban fabric and its peripheral edges, which are increasingly characterized by urban fragmentation and disconnection. Intensifying the presence of greenery in the city by increasing the density of trees and designing ecological corridors to create continuity between green spaces may lead to changes that have an impact on spaces within cities. In investigating the characteristics that determine the perception of urban safety, for example, within urban parks, the definition of the border and the presence of gates are considered crucial factors. Even if traditionally the urban green park is enclosed, in many cities there are parks that do not have margins, staying open and accessible all day long and turning out to be safe spaces for citizens. Thus, the boundary and its definition are still an issue to be explored in the design of green spaces and in the determination of their urban safety. The topic is addressed through a discussion about the meaning of the word boundary and through an analysis of case studies of green space design projects, such as gardens and urban parks, where boundaries are observed as a category of space with different features that help define the character of the park and its relationship to the city.