Their 3,500-acre farm was failing in England's West Sussex. Isabella Tree and Sir Charles Burrell stopped farming it, and 20 years later rare birds, butterflies and wildlife have returned

The farm was failing, the soil was poor and the debts were increasing. Having carried on agriculture for many generations, Isabella Tree and Sir Charles Burrell were forced to make a decision which seemed almost unimaginable – that of stopping their attempt to run their 3,500-acre estate in West Sussex as a traditional farm. The situation that followed was the opposite of what they had anticipated, as per a report by University of Sussex.

Rather than pressing the fields to produce more, room was allowed for nature to take control. Initially, the change led to weeds, a state of untidiness and criticism. Then something remarkable started to take place. Insects came back, birds appeared and the wildlife which had become increasingly rare began to return.






Twenty years on from when Knepp started its rewilding project, the estate has now been inhabited by nightingales, turtle doves, purple emperor butterflies, beavers and white storks. What was once a farm finding it hard to survive has turned into a place where nature is literally coming back to life.

A struggling 3,500-acre farm in West Sussex took an unexpected turn

Their 3,500-acre farm in West Sussex was not thriving. The land had been farmed for generations, yet poor-quality clay soil made it increasingly difficult to keep the business profitable. Isabella Tree and Sir Charles Burrell were facing mounting debt and sleepless nights. Then they made a decision that seemed almost impossible at the time: instead of trying to force the struggling farm to produce more, they began stepping back and allowing nature to take the lead.

Twenty years later, the same estate looks remarkably different.

Nightingales sing across the land. Turtle doves have returned. Purple emperor butterflies have established themselves. Beavers are building dams, while white storks are nesting at Knepp Castle. Herds of cattle, ponies, pigs and deer now move through a landscape of scrubland, wild meadows, wetland and wood pasture.

What began as an attempt to find another future for a failing farm has become the 3,500-acre Knepp Rewilding Project, one of the most striking examples of how wildlife can return when nature is given room to recover.

Why did they stop farming the land?

The transformation did not begin with a grand plan to create a wildlife haven. Charlie inherited the estate from his grandparents, and although farming had continued there for generations, the difficult clay soil meant the operation was struggling financially.

“We were £1.5m in debt, we had sleepless nights, people’s jobs were on the line, and we were looking at ever more mounting debt while trying to stay competitive,” remembers Isabella.

Stewardship grants helped them clear their debts, while some of the farm buildings were converted for offices, light industry and storage.

At the same time, Isabella and Charlie were becoming increasingly aware of the wider problems surrounding biodiversity and sustainability. They began consulting scientists and experts and visited rewilding projects in the Netherlands to understand what might happen if they stopped managing the land in the conventional way.

They did not abandon the estate overnight.

“We didn’t do it in one fell swoop,” says Isabella. “We began with the area around the house because that felt right. We could hear the insects coming back, something we hadn’t even noticed we were missing as farmers. And we could feel the earth coming back to life.”

What returned when nature took over?

The changes became increasingly visible. Rare species that had struggled elsewhere began appearing at Knepp. Nightingales, turtle doves and purple emperor butterflies returned, while old English longhorn cattle, Exmoor ponies and Tamworth pigs began roaming freely across the estate.

Beavers were reintroduced in 2022 and began building dams. White storks also started nesting in oak trees and a disused chimney at Knepp Castle, marking the first time they had bred in the UK for more than 600 years.

A large skein of greylag geese now arrives at the enormous lake behind the castle.

That sight once would have worried the farm. “In the past, we would have seen them as bad news,” says Isabella Tree. “It would have meant they were eating our crops.”

Now the geese are welcomed.

The estate has also become a valuable place for scientific research. University of Sussex biologists Dr Chris Sandom, who specialises in rewilding, and Professor Dave Goulson, an expert in bee ecology, have carried out research examining how the restored landscape is affecting plants and animals.

Students have worked on projects involving everything from dung beetles to ecoacoustics, recording wildlife sounds to help measure biodiversity.

Could rewilding help farms too?

Isabella believes the benefits extend beyond Knepp.

She argues that healthy natural systems can support surrounding agricultural land by providing pollinating insects, helping restore soil and maintaining dung beetles throughout the year. She also says rewilding can help replenish the water table, reduce flooding, create buffers against drought and strong winds, and produce micro-climates that can benefit food production.

The early appearance of weeds and the untidy nature of the recovering landscape initially caused anger in the local community. But as the project developed and wildlife returned, support grew.

The idea has also spread beyond Knepp through the Weald to Waves project, which brings together farmers, landowners and communities to create connected wildlife corridors across Sussex.

“You cannot have individual pockets of biodiversity because they are doomed to fail,” points out Isabella. “And already biodiversity is crashing in them. We need to have these ribbons to connect them.”

What has Knepp become after 20 years?

The project is now commercially viable as well as ecologically significant.

Knepp produces 75 tonnes of organic meat each year from its cattle and deer herds. It has an organic market garden beside its restaurant and shop, while safaris, glamping and camping allow visitors to experience the rewilded landscape.

Isabella’s book, Wilding - The return of Nature to a British Farm, published in 2018 and winner of several awards, helped bring the story to a much wider audience. It has also inspired a documentary called Wilding.

“We didn’t envisage this project would be so successful; that within ten years we would have a thriving eco-tourism business,” says Isabella. “We thought if we could increase biodiversity just a little, that would be a really interesting experiment.”

The family is now deeply involved in the project. Their daughter Nancy is conducting PhD fieldwork at Knepp for Oxford on carbon storage through rewilding, while their son Ned runs the Wilding Kitchen café and restaurant.

For Isabella and Charlie, however, the most important measure of success is not commercial.

It is the return of life.

“One thing we are beginning to appreciate is that it’s not just the headline species, it’s the abundance. The earthworm or the crane fly may not be exciting species but they are food for everyone else. The more life there is, the more life there is.”

Last year, around 60 singing nightingales were recorded at Knepp, while turtle doves continued to increase, although Isabella says it may sadly be too late to save them from extinction in Britain.

The couple received the Zoological Society of London’s Silver Medal in 2023 for outstanding contributions to the understanding and appreciation of zoology. Isabella was also conferred an Honorary Doctor of Science at the University of Sussex’s Summer Graduation in 2024.

Yet recognition is not what appears to matter most to her.

“Nature is so much bigger than us. The systems, the processes, the powerful resilience of evolution – there are things we haven’t even begun to understand. It’s fascinating and humbling.”

The story of Knepp began with a farm that could no longer sustain itself in the way it had for generations. By stepping away from conventional agriculture and allowing nature to shape the land, Isabella Tree and Sir Charles Burrell watched that struggling landscape become a place where wildlife could return.

The result has been more than a change in farming. It has become an ongoing experiment in what happens when nature is given the opportunity to recover.

FAQs

1. Why did Knepp stop farming?
   The farm was struggling because its poor-quality clay soil made it difficult to remain profitable.
2. What wildlife returned to Knepp?
   Nightingales, turtle doves, purple emperor butterflies, beavers and white storks are among the species that returned.