The Swiss railway company SBB has installed its first CityTree at the Vulkanplatz exist at the Zurich Altstetten railway station. It consists of a fully automated irrigation and nutrient supply system and a vertical panel with evergreen moss. The supply system for the moss is powered by energy from solar panels installed in the tree. A bench is built into the base of CityTree, providing seating for passersby.

The CityTree absorbs particulate matter, nitrogen oxide and carbon dioxide while at the same time cools the ambient air, explains SBB. It is also powerful: one CityTree is the equivalent of 275 naturally grown trees when it comes to cleaning and cooling the air. The actual performance of the CityTree can be measured and analysed via a connection to the Internet of Things.

The SBB intends to test its CityTree over the next 16 months. If it performs as expected for the environment and receives a positive response from SBB customers, then the railway company will consider planting such trees at other stations too.