The Florence Charters underlined how important the concept of the time cycle is to ensure the conservation of a historic garden (art. 11), considering both the succession of its life phases and the cycle of the seasons (art. 2). Today's programming maintenance and management activities are even more important because climate change exposes historic gardens to unexpected risks for the balance of the plant system, the water structure, and the morphology of the land itself, mainly when characterized by a steep slope. The Conservation Management Plan is a useful tool for planning the management and conservation of collections, archaeological sites, buildings, and gardens. It has also been successfully applied to twentieth-century architecture as part of the Getty Foundation's Keeping It Modern program (2014-2020). In continuity with that experience, this text illustrates the results obtained by applying the Conservation and Management Plan to the park of the former Villaggio Sanatoriale di Sondalo in Alta Valtellina, a healing garden built between 1932 and 1940 and characterized by the integration of modern architecture, environmental therapy, and garden design. After the damage caused by the Vaia storm in 2018, a CMP was applied to protect the complex from the risks due to climate change, to plan maintenance, and to manage the agronomic-forestry, landscape, and architectural qualities of this large therapeutic garden in the centre of the Alps
