Dear Colleagues,

Green plants have always been a design element in the architecture of buildings and the urban decoration of cities. Recently however, it has been revealed that they play an effective role in tackling the negative environmental impacts and energy costs that result from the air conditioning units of buildings, enabling the utilization of spaces and surfaces otherwise not exploited in cities. The use of plant systems as a Nature-Based Solution (NBS) to improve the environmental and energy sustainability of buildings and cities is in accordance with the objectives of the COM (2013) 249 Directive "Green Infrastructures—Strengthening Natural Capital in Europe". In addition, the use of vegetation for reducing the energy costs of acclimatization in buildings has been considered by the Directive (EU) 2018/844 on Energy Efficiency and the European Green Deal 2021–2026 strategy. In this context, the plant phenomena of photosynthesis and evapotranspiration are particularly useful during hot seasons to reduce electricity consumption and CO₂ emissions that result from the air conditioning of buildings; moreover, plant-covered surfaces provide shade for and shield buildings’ outer surfaces. Thus, plant systems installed on buildings represent an attractive strategy to achieve the goals of energy efficiency and environmental regeneration, and can also involve growing food-based plants on urban green roofs and in greenhouses. This Special Issue aims to involve work from scientists and experts from various research fields on the use of vegetation to promote sustainability and energy saving, the acceleration of the decarbonization of cities, as well as the reduction of air pollution and the transformation of cities into sustainable and resilient ecosystems.

Dr. Carlo Alberto Campiotti
Prof. Dr. Carlo Bibbiani
Dr. Arianna Latini
Guest Editors

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• green walls
• green roofs
• green infrastructures
• air conditioning
• building energy efficiency
• urban nature-based solutions
• urban ecosystem services

Planned paper 1:

Tentative Title: Recycled substrates and plant cover affect temperature in Mediterranean extensive green roofs

Abstract: the paper deals with an experimental test comparing an extensive green roof set up in Pisa (Italy) , where 12 modules of 10 cm depth were filled with three substrates composed of compost from municipal mixed waste, pelletised paper sludge, and commercial tephra product (Vulcaflor), as follows: Vulcaflor + compost, Vulcaflor + pellet + compost, and Vulcaflor + pellet. The species planted  were chosen from
the herbaceous spontaneous vegetation of urban and rural swards, plus two sedum species. No irrigation or fertilization were performed during the trial. We focused on processes of plant communities and structure (biodiversity) in comparison with different substrates and different percentage of infertile material (i.e. paper sludge).

In addition, we evaluated the community assemblage dynamics. Climate data (minimum and maximum temperature, relative humidity and total precipitation) were acquired every hour from a meteorological station, located nearby. Also the temperature within the substrate have been monitored. One among the aims of the study is to assess the system regeneration when rain follows periods of heat and drought. We are currently evaluating other related issues such as the Green Roof thermal insulation properties in relation with plant communities and structure.