All cosmonauts and astronauts that fly with the Soyuz spacecraft plant a tree shortly before their first flight. Thomas Pesquet is no exception and he planted his trees on 10 November 2016, seven days before launch.
Thomas’ crewmates Peggy Whitson and Oleg Novitsky have both flown on a Soyuz spacecraft before so they didn’t plant a new tree but helped Thomas with his.
This tradition started with Yuri Gagarin, the first person to orbit Earth, when he planted his tree near the Cosmonaut Hotel in Baikonur in 1961. Naturally his tree is one of the largest.
Below is a gallery of all the trees from the ESA astronauts of the class of 2009, taken by Thomas: