There’s a time and a place for trees – don’t transplant them for our amusement | Rowan Moore

Making an exhibition out of living things rather defeats any environmental message they are supposed to conveyA gaggle of oak saplings has gathered outside Tate Modern. They were grown by the British artists Ackroyd & Harvey from acorns from the trees that the German artist Joseph Beuys had planted in the city of Kassel in the 1980s, in a “social sculpture” called 7000 Oaks. This temporary installation, the official blurb says, creates “a place for gathering and for rethink