Last week, the Municipality of Trieste announced the start of a large-scale felling of urban trees — 71 in total. While the city regularly removes trees it deems dangerous, this is one of the most extensive operations in recent years. The largest number of trees has been, or will be, removed along the Viale Miramare, with a significant number also felled along Viale XX Settembre.
Urban trees play a crucial role in improving the quality of the urban environment. They help mitigate the urban heat island effect, filter air pollution, and regulate stormwater runoff. Trees increase cities’ resilience to climate change and provide habitats for numerous plant and animal species. Beyond their environmental benefits, urban trees also deliver major social, economic, and health advantages. By improving air quality and lowering temperatures, they reduce respiratory illnesses, cardiovascular problems, and heat stress. Contact with green spaces has also been proven to lower levels of stress, anxiety, and depression, while improving concentration and overall mental well-being. Trees create pleasant and safe environments for walking and socializing, encouraging physical activity and social interaction — both of which contribute to better public health in the long term.
The trees felled along the Viale Miramare and Viale XX Settembre will eventually be replaced. The situation is very different in Cattinara, however, where nearly 400 large trees were cut down a year ago in a pine grove that cannot realistically be replaced. The destruction of this woodland to make way for a new children’s hospital and extensive parking facilities is particularly hard to understand given the well-documented health benefits of trees, as it significantly worsens the overall well-being of patients and healthcare staff alike.
The city administration is quick to point out that Trieste is considered a very green city. According to the Urban Ecosystem study by the environmental organization Legambiente, Trieste ranks near the top among Italian cities in terms of both the number of trees and the amount of green space per resident. The city does indeed have many parks, most of them well maintained, and its trees are meticulously catalogued. However, nearly all major parks are located on the city’s outskirts, linking Trieste to its natural hinterland, while the central areas — where most residents live — are comparatively lacking in green space.
This imbalance helps explain why a major study published a few years ago in the prestigious medical journal The Lancet placed Trieste at the very top of a ranking of more than 1,000 European cities with the highest number of premature deaths attributable to insufficient access to green space. Just below Trieste were other otherwise attractive cities such as Turin and Copenhagen. The main reason for their poor ranking was not a lack of parks, but their uneven distribution, which fails to provide equal access for all residents.
One of the reference points for the study was the World Health Organization’s recommendation that every home should have access to a green space of at least half a hectare within a maximum distance of 300 meters. A further refinement of this recommendation is the so-called 3–30–300 rule, which has gained traction in recent years as a powerful tool for planning urban public space. The rule states that everyone should be able to see at least three trees from their home, that each neighborhood should have at least 30 percent tree canopy cover, and that every resident should have access to a public green space within 300 meters of their residence.
Many European cities have begun to green their public spaces aggressively in recent years. Barcelona, for example, is transforming formerly traffic-heavy streets into green corridors, and former intersections and parking lots into small parks. Vienna uses every street redesign as an opportunity to plant new trees and encourages residents to create small green oases themselves. Paris has set itself the goal of planting 170,000 new trees by 2026 as part of a broad program to reshape its urban environment.
It is time for Trieste to embark on an equally ambitious transformation of its public space — and to use the 3–30–300 rule as a guiding principle. Doing so would help prevent many premature deaths and better prepare the city for the challenges of climate change.
Originally published in Primorski dnevnik, 18 December 2025.