German artist Joseph Beuys embarked on an ambitious project 1982 to plant 7000 trees throughout the city of Kassel as part of `Documenta 7?. Beside each tree there was to be a basalt stone column. The project received funds from the Dia Art Foundation in New York, but a substantial amount was also raised through the sale of works by thirty-four internationally recognised artists, including Warhol, who supported the project. Although Beuys died before the project was finished, his son completed it in 1987. This poster is advertising the exhibition that took place at the Kunsthalle Tubingen and features the names of all those who donated work.