What is the 3-30-300 rule?

The 3-30-300 rule, devised in 2021 by Dutch ecologist Cecil Konijnendijk, establishes three measurable requirements: each person must see at least three trees from the windows of their home, school or workplace; each neighborhood must have at least 30% leaf cover; no one must live more than 300 meters from a quality equipped green space, that is, 5 minutes on foot.

How much urban greenery do Swiss cities have?

According to the European study by the JRC of the European Commission and the University of Copenhagen on 862 cities, only 28% of the Swiss population lives in neighbourhoods with at least 30% tree cover. Overall, just 13.5% of Europe's urban population lives in areas that meet all three criteria of the 3-30-300 rule.

What are the squares in Ticino most affected by heat islands?

The article identifies three emblematic examples: Piazza del Sole in Bellinzona, the Roundabout of Piazza Castello in Locarno and Piazza Bernardino Luini in front of the LAC in Lugano. These spaces are transformed in the warmer months into very hot areas that are almost impractical, functioning as real thermal accumulators.

How do you fight urban heat islands?

The studio proposes architectural solutions (green facades, new generation materials that reflect heat) and urban forestry (trees of significant size, quality public parks). However, temporary remedies such as water vaporisers or mobile greenery are not enough: a radical paradigm shift in spatial planning is needed.

Is there a difference between Northern and Southern Europe?

Yes, strong geographical disparity. Northern European cities such as Helsinki achieve excellent levels of compliance with the 3-30-300 rule, while in Southern Europe cities such as Athens and Barcelona have percentages below 3%. This means that the vast majority of the population in Mediterranean cities does not benefit from minimum urban green standards.

Urban green: the 3-30-300 rule for cool cities (cross-border guide)

Di Redazione Frontaliere Ticino · Published on 9 September 2026

Piazza del Sole in Bellinzona with buildings and minimal vegetation, example of urban heat island

European study of 862 cities: 28% of the Swiss population lives in green neighbourhoods. Rule 3-30-300 points the way to cooler cities

Context

In a nutshell

European study of 862 cities: only 13.5% of the urban population lives in compliant green areas
The 3-30-300 rule establishes three parameters: see 3 trees, 30% leaf cover, 300 m from green space
Ticino squares such as Bellinzona, Locarno and Lugano suffer from almost impassable urban heat islands

Key facts

What: European study on urban greenery and heat islands in 862 European cities
When: Published in Nature Communications (research year not specified)
Where: 862 European cities, including several Swiss companies
Who: Joint Research Centre (JRC) of the European Commission and University of Copenhagen
Amount: 13.5% of the urban population lives in neighborhoods that meet all three criteria of the 3-30-300 rule

# Urban heat islands transform European cities

Summer in the city is increasingly synonymous with oppressive heat and tropical nights. A phenomenon that directly impacts the quality of urban life and that is not only a subjective perception, but the direct result of urban heat islands. This microclimatic effect, typical of heavily cemented areas, transforms squares and streets into real thermal accumulators. Asphalt and concrete absorb solar radiation during the day and then slowly release it in the form of heat at night: temperatures do not drop and citizens find no relief at night.

A study published in the prestigious

Operational details

The North-South divide: when green abandons Southern Europe

A stark geographic disparity emerges from the data of the European study. While cities in Northern Europe like Helsinki come close to excellent compliance with the 3-30-300 rule, in Southern Europe like Athens and Barcelona the percentages plummet below 3%. This means that the vast majority of the population in Mediterranean cities does not benefit from the minimum urban green standards required by the formula guiding contemporary planning.

For Swiss cities, including those in Ticino, the picture is intermediate but concerning. Only 28% of the population lives in neighborhoods with at least 30% tree canopy coverage. This data reveals that most inhabitants do not even enjoy one of the structural criteria of the 3-30-300 rule. Urban planning must address this deficit with urgency, as climate change promises increasingly frequent and intense heat waves that will put urban resilience to the test.

Architectural solutions and urban reforestation

The solutions to combat urban heat islands are not limited to temporary remedies. The source identifies two categories of complementary interventions: architectural ones and those involving rethinking urban green. According to the source, some solutions are architectural and can be integrated directly into buildings such as green facades or next-generation materials capable of reflecting solar heat.

…

Key points

What does the European study mean for those living in Switzerland

The JRC research examined 862 European cities under the magnifying glass, including various Swiss realities. The numbers are clear: 28% of the population lives in neighborhoods with at least 30% tree coverage. This means that 72% of residents live in areas that do not even meet the first criterion of the 3-30-300 rule.

For Swiss citizens, this study represents a call to action towards local administrations. Asking your municipalities and cantons to adopt the 3-30-300 rule as a guideline for territorial planning is the first concrete step. The solution is not temporary. The source is clear: water sprayers and small mobile green corners are not enough. What is needed is a radical paradigm shift in territorial planning.

Municipalities can increase urban afforestation by planting trees of significant dimensions in squares, along streets and in public gardens. It is possible to promote green facades in private and public buildings through municipal incentives. The use of new-generation materials that reflect heat rather than absorb it can integrate green interventions. It is essential to ensure that no citizen lives more than 300 meters away from a quality equipped green space, according to the criterion established by the 3-30-300 rule.

For those who live or work in Switzerland, the message is unambiguous: the quality of urban life and climate resilience depend on a regeneration of public green spaces. Climate change accelerates the phenomenon of heat islands, making the intervention of administrations urgent. Discover how it is possible to make your city more livable and sustainable in the long term, consulting the available data on urban green in your region.

Source: rsi.ch

Frequently Asked Questions

What is the 3-30-300 rule?: The 3-30-300 rule, devised in 2021 by Dutch ecologist Cecil Konijnendijk, establishes three measurable requirements: each person must see at least three trees from the windows of their home, school or workplace; each neighborhood must have at least 30% leaf cover; no one must live more than 300 meters from a quality equipped green space, that is, 5 minutes on foot.
How much urban greenery do Swiss cities have?: According to the European study by the JRC of the European Commission and the University of Copenhagen on 862 cities, only 28% of the Swiss population lives in neighbourhoods with at least 30% tree cover. Overall, just 13.5% of Europe's urban population lives in areas that meet all three criteria of the 3-30-300 rule.
What are the squares in Ticino most affected by heat islands?: The article identifies three emblematic examples: Piazza del Sole in Bellinzona, the Roundabout of Piazza Castello in Locarno and Piazza Bernardino Luini in front of the LAC in Lugano. These spaces are transformed in the warmer months into very hot areas that are almost impractical, functioning as real thermal accumulators.
How do you fight urban heat islands?: The studio proposes architectural solutions (green facades, new generation materials that reflect heat) and urban forestry (trees of significant size, quality public parks). However, temporary remedies such as water vaporisers or mobile greenery are not enough: a radical paradigm shift in spatial planning is needed.
Is there a difference between Northern and Southern Europe?: Yes, strong geographical disparity. Northern European cities such as Helsinki achieve excellent levels of compliance with the 3-30-300 rule, while in Southern Europe cities such as Athens and Barcelona have percentages below 3%. This means that the vast majority of the population in Mediterranean cities does not benefit from minimum urban green standards.