Mr Wells said the aim was to create an artwork using non-toxic materials, for example chalk, charcoal and recycled cardboard, which would then turn into something new — "from degrowth to regrowth".
Ms Penwarden said by burying the artwork under a native tree provided by Extinction Rebellion, people could transform their feelings of grief or sadness about the state of the planet into something positive.
The event will take place from 3pm to 5pm this Saturday at 941 Blueskin Rd, Mount Cargill.
Art materials will be available and pumpkin soup will be offered for those attending.