It's not really a tree. It's a tower filled with different types of moss, which eat up particulates and nitrogen oxides and at the same time producing oxygen.
It has its own irrigation and energy system and also collects data about the environment surrounding the "tree."
If you live in London and want to see them, you'll find a couple outside Leytonstone subway station and on the intersection of Leytonstone High Road and Crownfield Road.
This tree is called CityTree and comes from a company called Green City Solutions, based in Germany.
They write this about CityTree:
"The ability of certain moss cultures to filter pollutants such as particulate matter and nitrogen oxides from the air makes them ideal natural air purifiers.
But in cities where air purification is a great challenge, mosses are barely able to survive due to their need for water and shade.
This problem can be solved by connecting different mosses with fully automated water and nutrient provision based on the unique Internet of Things technology."
Send this article to your local city representative and urge them to get it for your city.
News tip from Henrik Ahlén.