DEPENDING ON YOUR definitions, this particular essay has taken three months to write and the book of essays that it’s a part of has taken – again, depending on your definitions – five years. Saplings grow far more quickly than my manuscript has. The production timeline of your average physical book is easily long enough for an entire ecosystem to be destroyed. This should make me write faster, but in fact the opposite has happened.

Writers love to wrestle with trees – so rich are their metaphoric possibilities, so soothing is the light that filters through their leaves. I once stood under a grove of horse chestnuts in London’s Kew Gardens as pollen rained down through shafts of sunlight and thought to myself, Ah, this is what Philip Pullman calls Dust. Then, having had that thought, I lay down under one particular chestnut, or should I say within the chestnut, for its low boughs rested on the ground and enclosed the space and therefore me entirely, and I had a nap. Trees are not good for productivity. They encourage sloth (or should I say sloths, as those animals have arms that are longer than their legs and curved feet, both features being really useful if you live in a tree). Visiting some of the more remote trees takes time: you have to get on planes, hire cars, walk for miles. Processing all that you see, and read, takes even longer. The unravelling of millions of years of evolution takes some time to wrap your head around too, especially if, like me, you’re still trying to come to terms with what came first: the splendour of it all.