New Zurich Tree Protection Act: Felling only permitted with authorisation for trees with a trunk circumference of 1 metre or more

Zurich is becoming greener – at least if the city council has its way. With the partial revision of the Building and Zoning Ordinance (BZO), the city introduced a new regulation on tree preservation in spring 2025. In future, trees with a trunk circumference of more than one metre (measured at a height of one metre above the ground) may only be felled with express permission. 

The provision applies to the entire settlement area, with the exception of forest and predominantly road space areas. Multi-stem trees are also covered by the rule: if one trunk measures more than 80 centimetres or the two thickest trunks together have a circumference of more than 120 centimetres, a permit is also required. 

A felling permit will only be granted if certain conditions are met – for example, if the tree has reached the end of its natural life, poses a danger to people or buildings, or would disproportionately restrict the use of a property. As a rule, a replacement planting must be carried out to compensate for the loss of greenery. 

The new regulation is already taking effect: according to Section 234 of the PBG, it already applies to current building applications as part of what is known as ‘negative retroactive effect’. This means that building contractors and owners should adapt their plans to the new requirements at an early stage. 

With this tightening of regulations, the city of Zurich aims to promote biodiversity, reduce heat stress in densely built-up areas and improve quality of life in the long term. For real estate development, this also means new framework conditions – and the opportunity to bring nature and building culture even more into harmony in the future. However, there are also unknown, new dangers lurking for developers and construction projects.