Green Balconies: Enhancing urban spaces through social and environmental contribution

Abstract

Urban greening is receiving an increased interest in urban areas as a solution to address and adjust to climate change. The contribution of urban greening can be assessed on 2 levels: environmental and human well-being. Various typologies of urban green spaces have been explored; most of which are public and require large open spaces. In urban settings where cities are becoming denser and streets narrower, there is a need for a new approach. Vertical greening systems are a way to address this challenge. However, green walls and facades need be established and maintained with significant resources and coordinated efforts. Thus, there exists an underexplored, popular, practical, and affordable private VGS typology: green balconies and terraces. Many tools are available to assess the impact of horizontal green spaces by measuring canopy cover. However, none of these methods have been used to assess the canopies of potted ornamental plants typically used on balconies. The tool to measure canopy contribution of green balconies will need to be suitable in that it should accommodate for the scale and setting of these private green spaces. Also, literature is also lacking regarding the contribution of green balconies to residents’ wellbeing. Thus, this study aims to 1) measure the canopy contributed by green balconies to explore their potential impact on the urban environment 2) understand why urban residents plant their balconies. The outcomes of this research will contribute to the development of a citizen-science tool, a mobile phone application, that will allow residents to understand their contribution to the neighborhood and city after they upload information about their balcony plants. The first objective is reached through the 3D reconstruction of balcony plants using iPhone 14 laser. The second objective is reached through a thematic analysis of semi-structured interviews with residents who have planted or not their balconies. Our results show that Alpha Shape reconstruction method obtained a more accurate volume, considering trickier variations in plant structure. Also, 3D point clouds obtained from iPhone 14 laser are affected by environmental and physical factors. The most contributing specie to urban greening is Schefflera actinophylla with a CV = 0.5 m3. By extrapolating this result to a typical building in Greater Beirut, Lebanon, the building contribution could be equivalent to 6 SUTE. The thematic analysis of the GB interviews deduced the following themes: constraints to green balconies, mental well-being, environmental well-being. The thematic analysis of the NGB interviews deduced the following themes: personal constraints, contextual constraints and suggested drivers to plant balconies. The findings of this study prove that green balconies have the potential to contribute to the urban environment as much as small urban trees as well as to the mental well-being of urban residents, by providing private visual and physical accessibility.