Urban green infrastructure and the conservation of immovable cultural heritage: a symbiotic approach to climate resilience

The increase in unfavourable climatic events such as heatwaves, droughts and extreme rainfall is one of the greatest challenges of climate change and can lead to a potentially irreversible loss of natural and cultural assets in the urban environment. In this context, green infrastructure, i.e. strategically planned green spaces that provide ecosystem services, is a widely recognised approach to mitigate the effects of climate change in the urban environment [1]. While the environmental and health benefits of green infrastructure are widely recognised, its impact on heritage conservation has been surprisingly overlooked. Despite the proven protective role of vegetation and its contribution to site identity, its proximity to cultural heritage assets is still a concern for heritage managers as it harbours potential fire hazards, retains moisture and leads to biodegradation. Against this background, the JPI project ATLAS “Studying symbiotic scenarios linking Heritage assets and green areas to prepare Historic Cities to face Climate Changes” aimed to develop new tools and protocols to assess and manage the impact of climate change on the conservation of immovable heritage assets and green infrastructure in historic cities. As a first step to assess the potential (positive or negative) impact of green infrastructure on immovable cultural heritage, we quantified the presence of biological particles of plant origin and possible degradation products related to their presence on facades of cultural buildings. We collected samples from 47 surfaces on 12 different buildings in the city of Treviso. The surfaces were sampled with Fungi-Tape, which was later analysed under a microscope to identify and count plant particle elements. The number of plant particle elements was modelled as a function of the area of the nearest green space, the distance to it and the structural characteristics of the vegetation. The wall surfaces were analysed with portable instruments (portable microscope, Raman spectroscopy) to investigate their morphology and the possible presence of residues coming from the plants. Samples were collected by brush from each surface and analyzed under the optical microscope and with FTIR spectroscopy to chemically characterize the substances deposited on the surface. Preliminary results suggest that proximity to green infrastructure may influence the deposition of plant particle elements on building surfaces. However, the results should be integrated with the contribution of green spaces in determining the identity value of a site and the potential protection of surfaces from pollutants to quantify the balance between positive and negative effects of green infrastructure on architectural heritage. References [1] X. Fang, et al., 2023, Sustain. Cities Soc., http://10.1016/J.SCS.2023.10484