Basel-based artist Klaus Littmann set up the forest of 300 trees in Klagenfurt's 30,000-capacity Woerthersee stadium for the "For Forest" exhibition that will run until Oct. 27.
While climate change has recently become a pressing political issue in much of the world, the idea for the exhibition is not new - Austrian artist Max Peintner created a drawing in the 1970s that would come to inspire Littmann's installation.
Peintner thought about industrialisation and its effect on nature, the Italian landscape artist who planted the forest, Enzo Enea, said.
"I see the problems in Asia, in China, how the cities are built without much greenery," he added. "People need nature."
Visitors seemed to well receive the exhibition's environmental message.
"It has a huge effect to see a forest inside a stadium," Lucrezia from Italy said. "We're so used to see it everywhere, but once it disappears - as it's disappearing in the Amazon - then it gives the right perspective of what it means to lose a forest,"