Open Data Insight of the Day

Urban trees are essential infrastructure in cities: they improve air quality, store carbon, manage water, reduce heat, support biodiversity, and enhance human wellbeing. Their benefits go far beyond aesthetics, making cities healthier, more resilient, and more pleasant places to live—especially as urban areas continue to densify. Because many large trees are aging and take decades to mature, continuous planting and careful protection are crucial for future generations. In Basel, this importance is reflected in the care of over 30,000 documented urban trees, maintained by the Stadtgärtnerei and recorded in a publicly available open-data inventory.

In Basel, there are a total of 31,975 trees, representing 557 different species and 94 genera. The oldest known tree in the city is a Sommer-Linde, which has stood for 266 years at Münsterplatz.

The streets and parks of Basel are predominantly shaped by the Krim-Linde, Gewöhnliche Platane, Gemeine Rosskastanie, Spitz-Ahorn, and Feld-Ahorn, which are the top five species by count. The most common genera include Linde, Ahorn, Rosskastanie, Platane, and Eiche. The top five locations with the most trees are Kannenfeldpark, Bruderholzallee, Riehenstrasse, St.Galler-Ring, and Schützenmattpark. In terms of location types, the majority of trees are found along streets, in public green spaces, and on school and kindergarten grounds.

Communities in Basel vary in their tree density. Vorstädte, Wettstein, and Kleinhüningen boast the highest number of trees per 1,000 inhabitants, while Matthäus, Gundeldingen, and Am Ring have the fewest.

The data highlights the constant need to maintain tree health, particularly during periods of increasing heat and prolonged dry conditions. In 2026, a total of 200 trees are scheduled for replacement, including some of the oldest and thickest trees such as the 155-year-old Rot-Buche on Reservoirstrasse and the thickest Kanada-Pappel on Bachgraben-Promenade. These examples illustrate that, in some cases, even large and long-established trees of impressive species must be replaced to ensure long-term safety and ecological resilience.