Mannheim
Mannheim, a dynamic city in south-western Germany, is home to around 320,000 residents.
Positioned at the confluence of the Rhine and Neckar rivers, it is a key industrial and cultural hub in the state of Baden-Württemberg. Mannheim takes ambitious steps towards sustainability through its Climate Action Plan 2030 and its designation as a Smart City model by the German government. Roughly 30% of the city consists of green and open spaces, including Luisenpark and Herzogenriedpark, which play a vital role in climate resilience.
The city promotes citizen engagement through initiatives such as the Mannheim 2030 Local Agenda and digital platforms for participatory planning. Building on these efforts, Mannheim continues to involve residents in greening neighbourhoods and improving the monitoring and maintenance of green spaces.
Combining citizen insight and tree data shape cooler public spaces.
Mannheim engages residents in monitoring urban trees and shaping more comfortable, climate-resilient public spaces, linking its participatory Tree Registry campaign with efforts to better understand how people experience heat in the city. This combined approach connects long-term urban greening with everyday perceptions of comfort in public spaces.
Using Partimap, a web-based survey tool, trained interviewer volunteers gather feedback from passersby in central city squares such as Paradeplatz and Friedrichsplatz. Participants indicate where they feel most or least comfortable and why, reflecting on factors such as shade, greenery, water availability, and surrounding urban form. The campaign places particular emphasis on including older adults and other heat-vulnerable groups to ensure a more inclusive understanding of public space needs.
These citizen insights are complemented by data from Smart City Mannheim’s wider sensor network and enriched through ongoing tree monitoring via the “Urban ReLeaf – Mannheims Bäume” app, where residents record tree species and condition. Together, these integrated data streams provide a more holistic understanding of urban environments, supporting responsive climate adaptation strategies and guiding the design and maintenance of greener, more liveable public spaces.
Themes
Greenspace
Perception
Stadtbäume
Sensors/Data/Technology
Mobile
Application
Mannheim’s approach
Pop Up Community and Culture Labs
Urban ReLeaf Pop-Up Labs are short-term creative initiatives that transform citizen-generated environmental data into accessible community and cultural experiences, connecting science, creativity and local knowledge to make climate challenges visible and meaningful.
In Mannheim, the Pop-Up Lab focuses on “Staying Cool in Mannheim’s Public Spaces”, highlights the ecological and social value of urban trees. Using mapping and planting data, creative practitioners develop interactive ways for residents to engage with this information and understand its role in climate resilience. The project connects communities with local green infrastructure and encourages shared responsibility, highlighting the importance of urban trees for cleaner air, cooler cities and a more liveable everyday life.
