Only 10.6% of Wallonia’s population lives in neighbourhoods that meet the recommended 30% tree canopy cover, according to a new report published Tuesday by the Walloon Institute for Evaluation, Forecasting and Statistics (Iweps).
The findings suggest a growing imbalance in the region’s urban greening efforts, especially in densely populated municipalities.
The 3-30-300 rule, increasingly adopted in urban planning frameworks globally and now promoted in Wallonia, sets three key targets: every resident should be able to see at least three trees from their home, have 30% tree cover in their neighbourhood, and access a green space within 300 metres of their residence.
Iweps data shows that while 94% of Walloons can see at least three trees from their homes, and 78% live close to a park or green space, only a fraction enjoy sufficient canopy coverage.
The lack of tall trees—defined as those at least three metres high—particularly affects residential neighbourhoods, where the environmental and psychological benefits of tree cover are most impactful.
“Each of the three conditions of the 3-30-300 rule contributes to benefits for human physical and mental health,” the report emphasises.
“A large body of scientific literature shows that the presence of vegetation plays a central role in improving air quality, reducing stress and noise, offering recreational opportunities, and moderating temperatures—especially during heatwaves.”
Interestingly, the report notes that the municipalities with the lowest canopy percentages are not necessarily the most urban. However, urban areas such as Liège and Mons are home to the largest number of residents affected by insufficient greening.
These cities have already begun implementing comprehensive urban greening plans, but the report highlights that more localised strategies are necessary.
“This quantitative monitoring of the greening of living spaces must be accompanied at the local level by qualitative approaches in order to better characterise the current cover, its access and its effects, and to develop solutions adapted to each context,” the authors argue.
As climate change intensifies, tree canopy cover is gaining importance not just for biodiversity, but also as a frontline defence for public health. The Iweps findings suggest that while Wallonia is making progress, targeted efforts are still needed to bring canopy levels in line with international standards.
