Monument protection as a limiting factor for large scale vertical greening system implementation to counteract indoor heat stress – a GIS-based analysis for Berlin, Germany

Vertical greening systems (VGS), as proven strategy for adaptation to heat stress, are prohibited for monument-protected buildings and façades. To what extent monument protection effectively limits the implementation of VGS in heat stress affected city centers has not been quantified yet. In this study, the ratio of buildings under monument protection was quantified for Berlin, Germany, using a GIS analysis. It was then compared to a map of potential heat stress. This was done for the entire city and the inner-city area on block-scale. Therefore, maps of the Berlin buildings, monuments and blocks were processed. The ratio of buildings under monument protection was calculated for each block of Berlin. To not deform the outcome, urban green areas were cut out of the maps. Inside the 80 km 2 city center of Berlin, which is severely affected by heat stress, the range of monument protection prohibiting VGS in the individual blocks ranges from 0 % to 100 %. However, 25.42 % of the building façades in the city center and 16.20 % for whole of Berlin are protected on average and therefore cannot be greened. Compared to other restricting factors, monument protection does not generally hinder large scale implementation of VGS in Berlin. Nonetheless, 102 potentially heat stress exposed blocks inhabited by 48,122 people cannot be greened due to monument protection. This demonstrates that VGS should be discussed as exception from monument protection that can be justified by a predominant public interest. It also points to the need of minimal invasive and mobile greenery technologies, which would enable heritage-protection conform greening.