Urban forests and green spaces provide essential benefits for city dwellers, from improving physical and mental health to mitigating the effects of climate change. However, many cities worldwide are struggling to maintain and expand their green infrastructure in the face of rapid urbanization and development pressures.
The 3-30-300 rule provides a simple, comprehensive yet powerful framework for creating more livable, sustainable, and equitable cities through strategic urban greening. The comprehensiveness of the guideline was especially stressed in the webinar – contributing to its strong resonance with people.
Who is Cecil Konijnendijk?
1. The 3-30-300 rule
The 3-30-300 guideline was developed based on growing research demonstrating the importance of accessible, high-quality urban green spaces for human health and wellbeing.
The 3-30-300 rule
- 3 trees: Every resident should have access to at least 3 large, mature trees from their home, workplace, or school.
- 30% canopy cover: The overall neighborhood should achieve at least 30% tree canopy coverage.
- 300 meters: All residents should live within a 300-meter (roughly 5 minute) walk of a high-quality public green space.
These interconnected targets are designed to ensure that urban forests and green infrastructure provide maximum benefits to communities.
2. The key visions and principles underlying the rule:
The 3-30-300 Konijnendijk approach is rooted in ensuring proximity, connectivity, diversity, and equity of green spaces.
- Proximity: Ensuring green spaces are close and accessible to urban residents.
- Connectivity: Linking green spaces together into a cohesive network.
- Diversity: Promoting a broad range of tree species and green infrastructure types.
- Equity: Ensuring equitable access and distribution of urban green spaces.
These key principles form the foundation for creating more livable, sustainable, and equitable cities through strategic urban greening.
3. The evidence base
The 3-30-300 guideline is grounded in an ever-growing body of scientific research on the impacts of urban greening. Some of the key findings highlighted in the webinar include:
- Over 4% of summer mortality in European cities is attributable to urban heat islands. Increasing tree cover in cities to 30% can reduce urban temperatures by up to 1.3°C and prevent 1/3 of premature deaths attributable to urban heat islands in summer.
- Up to 30% canopy cover is associated with higher birth weights, lower incidence of psychological distress, and improved overall health outcomes.
- Having a high-quality public green space within 300 meters of one’s home is linked to increased physical activity, social interactions, and restoration of attention and cognitive function.
4. Implementation and good practices
Despite the compelling evidence, many cities around the world are actually seeing a decline in their urban forests and green spaces. This alarming trend has spurred a growing number of municipalities to proactively adopt the 3-30-300 guideline as a policy target.
In Europe, the 3-30-300 rule has seen the most uptake in Denmark, the Netherlands, and Sweden, as well as at the UN and UNECE level. Notably, the city of Malmö, Sweden has formally incorporated the guideline into its urban planning processes, requiring all city departments to work towards achieving the 3-30-300 goals. Belgium, has even conducted comprehensive assessments of the 3-30-300 rule for all of its regions.
5. Adapting the Framework
While the 3-30-300 guideline provides a clear, evidence-based framework, experts emphasized the importance of adapting it to local contexts and scaling the approach over time. In dense urban centers, for example, it may be challenging to achieve the 300-meter access target. In arid climates, the tree species selection and water management strategies will need to differ from temperate regions.
The webinar highlighted several key principles for successful 3-30-300 implementation:
Integrate the guideline with other relevant policies, plans, and targets
Focus on large, high-quality trees to maximize canopy coverage
Adopt a long-term, ecosystem-based perspective
Engage citizens and leverage partnerships for implementation
Promote diverse tree species and green infrastructure types (10-20-30 rule for urban tree diversity)
Particularly when working in built-up urban areas with limited space, Cecil Konijnendijk stressed the importance of creativity, perseverance, and a willingness to “not get stuck in limitations.” Exploring innovative approaches like using industrial and business parks, enhancing green connectivity, and deploying water-efficient technologies can help overcome barriers.
6. The Role of Citizens and Advocates
7. Measuring Progress and Impact
To track progress towards 3-30-300 goals, cities are deploying a range of tools and metrics. These include traditional canopy cover assessments, geospatial mapping of tree locations and green space access, and even emerging “exposure” and “hybrid” indicators that combine spatial data with on-the-ground surveys.
In ASITIS we provide a unique and precise solution for calculating the 3-30-300 rule based on OrthoPhoto and satellite data, with outputs containing GIS data, including shapefiles for each rule evaluated, a final report with results and tailored recommendations and engaging infographics summarizing the findings.
8. Looking to the Future
As cities worldwide grapple with the twin challenges of rapid urbanization and climate change, the 3-30-300 guideline offers a powerful, holistic framework for creating more livable, sustainable, and equitable urban environments. By ensuring all residents have access to the natural benefits of trees and green spaces, cities can unlock a wide range of social, environmental, and economic rewards.
The webinar highlighted the tremendous potential of this approach, showcasing success stories and innovative solutions from across Europe.
Special thanks to School of the Environment, University of Toronto for organizing this event, as raising awareness of this topic is crutial.
