Early in the book, Macfarlane describes flying over the Scottish Outer Hebrides in a twin-prop plane. He saw “the tawny expanse of Mointeach riabhach, the Brindled Moor: several hundred square miles of bog, hag, crag, heather, loch and lochan that make up the interior of Lewis”. Across the aisle from him, two people looked out of the window. Macfarlane recounts: “One of them laughed. ‘We’re flying over nothing!’ she said.”

Seed fund

“If we just see a landscape as some kind of waste space and devoid of detail, it becomes more vulnerable to dismissal or disinterest or improper use,” Macfarlane tells me.

In Landmarks, he quotes the American essayist and farmer Wendell Berry: “People exploit what they have merely concluded to be of value, but they defend what they love, and to defend what we love we need a particularising language, for we love what we particularly know.”

A chapter in the book is dedicated to the Scottish-American John Muir, whose writings inspired the US president Theodore Roosevelt to create the country’s first national parks. “Muir gives me hope,” Macfarlane said in his talk at Hay. “His writing changed the course of landscape history. It’s the idea of hope in the dark.” He described the seeds of the bristlecone pine, which lie dormant in the soil and are germinated by forest fire. “Individual actions in culture – art, writing – can be dropped, like the pine seeds. They seem dead but decades later they can flare into life.”

Subtitled a “field guide to the literature of nature”, Landmarks is a work of great scholarship – but also a call to action. It explores “how reading can change minds, revise behaviour and shape perceptions”. And it fits within a wider resurgence of nature writing in Britain, including Costa award-winning H is for Hawk and The Shepherd’s Life, the memoir of a sheep farmer.

Macfarlane believes there is an “astonishing surging cultural energy that’s working across photography and art and in literature”. He credits it to an acute sense of loss. “It’s because we live in the shadow of destruction and damage, because we are a generation that’s grown up conscious of climate change, and that internalised anxiety at the world’s ongoing peril is a really powerful imaginative force that we don’t quite register in its full form but is deeply in us,” he says.

‘An A-Z of words lost’

Macfarlane was inspired to write the book both by discovering a “peat-deep word-hoard of Hebridean Gaelic” and after the culling of nature words such as buttercup and kingfisher from the Oxford Junior Dictionary, which he described at Hay as “an A-Z of words lost”. He thinks we can learn from how children encounter nature.

“The last chapter is about a group of children in a country park which has the busiest A road in the east of England on one side, and a hospital on the other,” he says. “It’s about the limitless wonder with which children meet even a very unwild place, which is an inspiration to all of us who’ve forgotten how to speak ‘childish’.”