At the end of a long week, on a day of high wind and changeable skies, we refreshed our somewhat battered souls by wandering over the river to seek out  the Chelsea half of Spontaneous City in the Tree of Heaven, a sculptural installation by London Fieldworks. The site: Cremorne Gardens, tucked away between the relentless traffic of Cheyne Walk and the ebb and flow of the Thames, a  pocket of greenery overlooked by the World’s End Estate. The work: bespoke wooden bird boxes clustered around the branching truck of a tree of heaven. I thought of shanty towns and swarming wasp nests – parasitical growth and abundance – but also of peaceful havens, bolt holes, respite from the grinding city; nature in the midst of harsh urban places; those unknowable creaturely lives carrying on around us, unconcerned with our petty cares. In a nutshell, perspective.