Wilding, by Isabella Tree

Wilding is an extraordinary book. It's horrifying, uplifting, a catalogue of things to despair about, a litany of things to be hopeful about. It changes the way you see the world - even well-known and much-loved landscapes. It's sobering, but also intoxicating.

It's about an ancient estate in Sussex called Knepp Castle. Charlie Burrell, the husband of the writer, Isabella Tree, had taken the estate over from his grandmother in 1987 and immediately set about modernising it: '... he began doing what every modern farmer is supposed to do: rationalise, intensify, diversify, and, if possible, spread fixed costs over a larger area.' The five tenant farms were struggling and ready to give up, so Charlie took them all back and began to amalgamate the dairies, streamline and improve farm buildings, and invest in expensive machinery. What happened next is complicated - but basically, for all sorts of reasons, it didn't work. By 1999 it was clear that the business was not viable: intensive farming, which was supposed to lead to healthy profits, was in fact resulting in huge losses. It couldn't go on.

It just so happened that in 1999, they had invited a tree expert called (appropriately) Ted Green, to come and investigate whether a 550 year-old oak tree could possibly be saved. He was optimistic, and he moved on to examine the other great oaks on the estate. He explained to the Burrells that they too were at risk - and the reason wasn't age: it was ploughing and compaction of soil due to cattle grazing. 

A tree's roots may extend two and a half times the radius of the crown, not far below the surface of the soil, where oxygen is available. But the roots are just the beginning. From the roots there extends a network of mycorrhizae - tiny filaments of fungus which take carbohydrates from the tree, but in return supply it with water and essential nutrients. It's far more complicated than that - but if this huge network is disturbed, the health of the plant, or tree, is affected. It's also affected by insecticides, herbicides and fungicides, all of which are part of the armoury of a modern farmer.

This is just one tiny piece of the jigsaw of reasons that made the Burrells decide to take a radically different approach: they would allow nature to take the lead, and see what happened. They were inspired by a Dutch ecologist, Frans Vera, who had used a similar approach on a reserve in the Netherlands called the Oostvaardersplassen. He believed in minimal intervention, in allowing natural processes to develop. This would, he thought - and actually did - result in a tremendous increase in biodiversity. It began when huge numbers of greylag geese found the marshy land, and consumed the vegetation that would otherwise have clogged up the open water. But to keep the geese coming, they needed grassland. So they introduced old, tough breeds of cattle and horses, similar to the large animals that would once have grazed the land thousands of years ago. And they left them to get on with it.

Well, it's all much more complicated than that. But perhaps you begin to get the idea. At the beginning of the book, Isabella Tree writes about turtle doves. There are now a number of pairs of turtle doves at Knepp - but almost nowhere else in Britain. The decline in numbers of this bird is far greater in the UK than anywhere else. Our population density is actually higher than that of India: there are so many of us that the pressure of any 'spare' bits of land is immense. Here in my own place, Cheddar, over the last forty years small orchards have disappeared, large gardens have been halved, fields are disappearing as we speak - because there are more of us, and we need more houses. So the wild places are disappearing, and with them, the nourishment that turtle doves, and many other species, need. 

Of course it's not all bad. There are success stories, such as the reintroduction of red kites, the increase in otters due to cleaner waterways, and so on. But overall, it's a sad story. 'In 1966, according to the RSPB, there were 40 million more birds in the UK than there are today.' There's a terrible list of declining species, but perhaps an effective indicator of the situation is that in terms of lost biodiversity, the UK is ranked twenty-ninth lowest out of 218 countries.

The book tells the story of how the 'wilding' of Knepp has led to massively increased biodiversity, and to the reappearance of masses of species of flora and fauna which have become rare elsewhere in our crowded country. It's absolutely packed with evidence and information - so much so that it's actually difficult to take it all in at one reading. One thing - it is not anti-farming. Clearly, this approach cannot be put into practice everywhere. But there is an enormous amount to be learned from it, and much that can be applied elsewhere. Even in small ways: I know now that ragwort, far from being the poisonous pest I had believed it to be, is actually an enormously valuable food source for many birds and insects during the autumn months - and is only very rarely damaging to horses and cattle. (Had I actually taken note of the evidence of my own eyes, I would have realised this; there is a great deal of ragwort on our hill, and in thirty five years, I've never once heard of any of the cattle that graze up there being made ill by it.) Towards the end of the book, Isabella Tree discusses how she envisages lots of small patches of wilderness in the UK - but joined up, connected, so that wild life has its own habitat alongside ours, instead of being gradually squeezed to the margins, and then to extinction.

Ragwort on the hill

On the nature-writing course I attended recently, and which I wrote about a couple of posts back, I was surprised to hear one of the tutors, Mark Cocker, say sadly after a walk down to the sea that he had passed fields that were little more than a desert in terms of wild life. But now I know exactly what he means. He talked also about how we, like all other living things, are part of a complex network of systems - like, perhaps, the ancient oaks with their mycorrhizae: everything is interdependent. If we lose a species of dung beetle - it matters. Yet we are losing masses of species, some we may not even have known existed.

We need to know about this stuff - and this book is a very good place to start.