Discovery: by Isabella Tree

Isabella Tree is a writer and conservationist. As the author of the wonderful bestselling book, ‘Wilding: The Return of Nature to a British Farm’, Isabella brought the concept of rewilding into the mainstream. The story of how she and her partner, Charlie, steered Knepp Estate away from conventional farming, and towards the biodiverse haven it now is, has paved the way for many more like them. The results speak for themselves and, coupled with her passion and knowledge of wildlife, Isabella is without doubt a pioneering figure within rewilding. Isabella continues to write, and has recently published a children’s book ‘When We Went Wild’. This article was previously published in American Vogue, and is shared in Heal's birthday blog series with their kind permission.

For the first time since we had started rewilding I sensed my husband Charlie’s resolve beginning to waver. Letters from neighbours were reaching a crescendo of outrage. Over the seven years since we began handing our 3,500-acre farm over to nature we had weathered complaints about our free-roaming animals, outbreaks of ragwort, unkempt hedgerows and thorny scrub desecrating the picture-postcard image of England’s green and pleasant land. Every time, we had held our nerve, sticking to the principle we had adopted at the start of the project: to sit on our hands and leave nature in the driving seat. This time, though, it seemed we might have come off the road.

Isabella Tree © Knepp Wildland

The culprit was creeping thistle: acres upon acres of it, 3ft-high, engulfing the Repton park around the 200-year-old castle and swathes of our West Sussex estate. Where, less than a decade earlier, there had been fields of barley, maize and wheat, now we had scenes from The Day of the Triffids. A pioneer of disturbed ground, the ‘cursed thistle’ can colonise at breathtaking speed. It breeds clonally and sends down deep but brittle tap-roots which, as any gardener knows, can regenerate from the tiniest fragment. Concerned the invasion might derail the whole project, Charlie was, reluctantly, considering reaching for the slashers and the herbicide.

Giving up farming had been a difficult decision. Farming is in Charlie’s family’s DNA, fortified with patriotic fervour from the days of Dig for Victory in WW2. But, on desperately poor soil – 300 metres of heavy clay – our arable and dairy business rarely made a profit. When Charlie inherited the estate, just 45 miles from central London, from his grandparents in the 1980s, it was losing money hand over fist. At the age of 23, Charlie applied what he’d learnt at agricultural college to try and turn its fortunes around: bigger machinery, new varieties of crops, state-of-the-art milking parlours, and liberally spraying with the latest fertilisers and pesticides. Nothing, though, could make our soil competitive. After seventeen years of losses we had worked up an eye-watering overdraft. By 2000 it seemed there was no alternative but to break with family tradition and find another way of managing the land.

Our inspiration for rewilding came from Frans Vera, a Dutch ecologist whose theories about free-roaming animals and natural habitat were, in 2000 - the year we sold our dairy cows and farm machinery - transforming nature conservation in Europe. In all our imaginings of our landscapes before human impact, Vera says, we’ve forgotten the vast numbers of megafauna – and most importantly, large herbivores - that would have driven ecosystems. Their impact on vegetation – grazing, browsing, trampling, rootling, wallowing, tree-breaking, de-barking, transporting seeds in their gut, hooves and fur – would have driven a kaleidoscope of complex, open, dynamic habitats, very different to the idea of ubiquitous closed-canopy forest we often have in our heads. Their dung, urine and carcasses are a vital part of the soil nutrient cycle. This is the secret of biodiversity, Vera says: if we want to recover wildlife in our depleted landscapes today, allowing large free-roaming herbivores to drive the system is key.

Photo © Knepp Wildland

Charlie had grown up in Africa and I’d worked for years as a travel correspondent. We’d seen wonderful wildlife the world over and never thought we could – or should – have it in our own backyard. We decided to put Vera’s theories to the test and embark on a ‘self-willed’ nature restoration project – or ‘rewilding’, as it has come to be known. We allowed scrub to take over the arable fields and corseted hedges to burst their stays. We smashed up old Victorian land drains and allowed ditches to fill. The surround-sound thrumming of insects, an almost instant result, was overwhelming - something we hadn’t even known we were missing.

Then we fenced our boundaries and introduced free-roaming animals. In place of the extinct aurochs - the wild ox - we released old English longhorn cattle, sturdy enough to survive outside all year. Exmoor ponies, an ancient breed of horse, mimic the actions of the extinct tarpan, and old-breed Tamworth pigs, wild boar. Red and fallow deer complete our Big Five – their various disturbances opening up opportunities for insects, fungi, lichens, wildflowers, small mammals and birds.

Mindful of over-grazing and browsing we keep the stocking densities low by culling. With too many herbivores, vegetation doesn’t have a chance to regenerate. But under-grazing and browsing is just as concerning. Too few, and eventually you get closed canopy trees – a relatively undynamic habitat, where only deer can thrive, much like the eastern seaboard of the United States. What you want is a battle between herbivores and vegetation which neither side wins. This creates all the messy margins, the dynamic kaleidoscope of habitats, which is rocket-fuel for wildlife across the board.

Photo © Knepp Wildland