Historical gardens as laboratories of participation: the Residences of the Royal House of Savoy in Turin between heritage, ecology, and urban planning

Urban greenery plays a crucial role in shaping the livability and resilience of cities, influencing environmental quality, social well-being, and cultural identity. In this perspective, historical gardens offer unique opportunities: they are not merely vestiges of the past but active laboratories for contemporary urban challenges. Their reactivation through innovative participatory approaches can foster community engagement and support the collective re-imagination of urban spaces. The historical parks of the Residences of the Royal House of Savoy in Turin, inscribed on the UNESCO World Heritage List, provides a fertile ground for reflection. Conceived between the 16th and 18th centuries as a network of palaces, villas, hunting lodges, the residences expressed political power, artistic innovation, and landscape control across Piedmont. Today, they constitute a unique cultural system where architecture and greenery are deeply intertwined, embodying centuries of design and care while revealing tensions between conservation, accessibility, and contemporary use. Beyond their aesthetic and heritage values, these parks offer opportunities to explore the therapeutic, social, and educational dimensions of urban greenery. Integrated into planning processes, such dimensions can activate models of participation that move beyond traditional consultation toward experiential involvement, co-design, and shared stewardship. This contribution examines participation in urban planning through the lens of historical greenery, framing gardens as active agents rather than static objects of preservation. The Savoy parks in Turin offer a testbed where representation and technology converge: physical and digital models, visual narratives, and interactive platforms make complex ecological and cultural values accessible, while sensors provide real-time data on comfort, perception, and environmental conditions. Combining subjective impressions with objective evidence, this dual approach generates hybrid methodologies that enrich participatory planning and strengthen dialogue between experts and communities. From a theoretical standpoint, the paper reflects on the concept of participation as a continuum, spanning from symbolic presence to genuine empowerment of communities. In the context of green heritage, participation cannot be reduced to occasional events or to the passive enjoyment of spaces. It must instead be structured around processes that allow different publics to rediscover, reinterpret, and co-manage shared resources. The stratified history and symbolic resonance of gardens, invite plural narratives: of memory, identity, ecological responsibility, and future resilience. To this extent, the theoretical foundations of participation intersect with critical heritage studies, environmental psychology, and the emerging discourse on green justice. Practically, the study discusses projects that combine sensory and sensor-based approaches. Visitors are encouraged to engage bodily - listening, touching, smelling - to rediscover the perceptual richness of the gardens, while technological devices gather environmental data and record user preferences and comfort levels. Integrating these modes of knowledge allows planners to address questions such as how users experience comfort and well-being in heritage gardens, which areas foster restorative experiences, and how these insights can inform maintenance and policy decisions. However, technological mediation raises questions of privacy, data ownership, and inclusivity, emphasizing the need for participatory frameworks that are equitable, transparent, and respectful of both heritage and human rights. Rediscovering historical greenery as a collective asset enables communities to practice shared responsibility and cultivate belonging. Combining sensory engagement, technological tools, and theoretical insights, they suggest a model of participation that is experiential, scientific, and democratic. Such a model informs urban planning not only in heritage contexts but also in the broader development of resilient green infrastructure, challenging planners, researchers, and policymakers to rethink the relationship between past and future, conservation and transformation, and expertise and everyday experience.