A successful proposal should:

• Develop a common framework to increasingly recognise and promote contact with nature, including protected areas and other green and blue spaces, as a cost-effective response for the prevention and treatment of human health and well-being;
• Propose an interdisciplinary and cross-sectoral approach, including the involvement of the health care sector, land owners, as well as green space management and nature protection sectors;
• Improve schemes monitoring nature-health linkages to enhance the evidence base and tools for the health care sector, green space management, nature protection, urban planning and landscape architecture;
• Develop longitudinal prospective methods, (quasi-) experiments or well-controlled interventions, to provide more evidence of the causal relationships between nature and health and well-being:
  • Understanding of when people explicitly choose to go to an urban green space and what experiences they have there (e.g., active versus passive activities).
  • Determining the type of interactions and dose of interactions necessary for long-term health and well-being benefits.
  • Understanding the mediators of the health-nature relationship, such as age, gender, socio-economic status or culture.
  • Considering the difference between greenness quantity and quality and determining which aspects of natural features are relevant to mental health.
  • Understanding how different geographical locations and factors such as population density affect the health-nature relationships;
• Test nature therapy sessions, identify best-practices and develop the necessary tools and guidelines for integration of nature-based care in the public health sector;
• Identify legal and administrative arrangements, partnerships, and financial mechanisms for implementation of nature therapy sessions.

Proposals should bring together from the start multiple types of scientific expertise in both health and natural sciences, as well as social sciences and humanities, together with a variety of community and health sector representatives, businesses, civil society organisations and citizens. Proposals should ensure that all evidence, information and project outputs will be accessible through the Oppla portal (the EU repository for nature-based solutions).

Social innovation is recommended when the solution is at the socio-technical interface and requires social change, new social practices, social ownership or market uptake. In order to achieve the expected outcomes, international cooperation is strongly encouraged, in particular with the USA, Japan and the LAC region.