Offering green roofs in a compact city: Benefits and landscape preferences of socio-demographic cohorts

Abstract

Urbanization and densification have extended some urban greenery skyward. Understanding expectations of aboveground green space can enhance public support and benefits. We evaluated the perceived benefits and preference for landscape elements of green roofs based on a questionnaire survey of 477 Hong Kong residents using principal component and cluster analyses. Benefits on recreation and health, air quality, and microclimate were strongly expected, but ecological and hydrological benefits were inadequately recognized. Respondents strongly preferred recreational hardware facilities like seats, kiosks and footpaths, soft landscape features like lawns, attractive flowers, pergolas and hedges, and simple ornamental planting design with low-stature vegetation and low biomass structure and complexity. Tree planting was the least desired among the three planting types. Hard landscape features were the least preferred, and some groups expected water features. Preference profiles identified six clusters of respondents, with inter-cluster dissimilarity associated with socio-demographic characteristics and benefit perception. The findings suggested that public education could enhance citizens’ knowledge on benefits to secure their support of environmentally-sound green roof design and a need for the user-oriented design of green roofs to cater to specific potential users. Strategically located sited could alleviate accessibility inequality in urban green space, especially for low-income people.