by Isabella Tree

'High up, skimming a tree's silhouette and framed against the sky, the emperors look black -- like a rainforest butterly. At a glimpse they can be mistaken for birds... The males attack anything that comes near them, defending their territory and the pick of the females. An unwary chaffinch is chased away. Blue tits shriek in alarm -- a comeuppance for them since, from October through to April... they are the butterfly's main predator. Emperors have even been known to attack sticks and bricks thrown up into the air. From time to time a couple , or even three, male emperors lock horns, tussling in flight -- 'having a bundle', as Neil puts it...'

 From 'Wilding' by Isabella Tree.


Thanks to our destruction of the environment, not only by our roads and shopping malls but also by modern farming practices, this large, blue-tit bothering butterfly, the purple emperor, has become very rare. Thanks to the courage and initiative of Isabella Tree and her husband, the purple emperor is now more numerous on their estate of Knepp, in Sussex, than anywhere else in Britain. By allowing Nature to take the lead in wilding their land they, unwittingly, created the best possible breeding environment for 'His Purple Majesty.'

In the same way -- by being brave enough to 'sit on their hands'  and allow Nature to come back on its own terms -- they have created a haven for nightingales. And Tree has a whole chapter on turtle doves, which begins:

More exciting even than the  nightingales has been the arrival, from the very brink of extinction, of turtle doves. There are estimated to be fewer than 5000 pairs left in the whole of Britain and only 200 pairs in Sussex. Knepp may be the only place in Britain where numbers have increased in recent years...

Something they learned is that what we think of as 'natural behaviour' in animals is often only a sad and sorry shadow of  nature. 


We uproot and plough-up and spray and destroy and so force birds, insects and animals to struggle for survival in the tiny areas we have no use for or deign to leave for them -- and we then think this desperate, marginal survival is 'natural' and write it up in our text books.

If Tree and her husband, Charles Burrell, had consulted these text-books on how to create a habitat for nightingales, they would have planted 'close canopy woodland', since nightingales are described as 'a woodland species.'  And they would have failed -- as modern attempts to enourage the breeding of nightingales in other places have failed.

Tree wrote a biography of the Victorian naturalist John Gould, (who worked with Darwin) and so she knew that Gould had described nightingales, which were far more common in his day, as 'generally' nesting on 'the side of a bank and occasionally in a shrub or bush.'  That's a far cry from 'woodland.' When the Burrells allowed their hedges to burgeon and their land to grow up with scrub (to the anger of many of their neighbours), the nightingales voted with their wings and moved in. It turns out that they don't really like woods at all. They much prefer more open, scrubby land with occasional thickets.

The same short-sightedness is found with turtle doves, which are described as 'farmland birds' who feed on grain. Yet all over Britain they are failing to breed on farmland, whereas at Knepp, where grain is no longer grown but where there are many wild flowers (such as the vetch which John Gould described them feeding on), they are flourishing. Could it be, Tree wonders, that the doves only feed on arable grain in desperation, as they are no longer able to find enough quantity of the wild seeds and shoots they would prefer?


It's a fascinating book, which describes how the Burrels broke their hearts trying to make modern, conventional farming pay on their 'Sussex clay', which was unsuitable soil for arable farming and only began to be so farmed at the outbreak of WWII, as part of the drive to produce more food. Farming had continued after the war, with plentiful (and expensive) use of artificial fertiliser and insecticides alongside heavy machinery which compacted the soil and pulverised the vital soil organisms, from fungi and bacteria to earth-worms. A horrifying fact is that, it seems, earthworms are rare on intensively farmed land. Earthworms -- as Darwin knew a hundred years ago -- are vital for fertile soil. What an indictment of 'conventional farming' which has only been 'conventional' since the 1940s when all those firms producing explosives turned to producing artificial fertiliser instead.

When the Burrells finally decided to give up the struggle, they looked round for some other way to use their land and happily came under the influence of  Frans Vera, who emphasises the importance of large grazing animals for the creation of the bio-diversity needed to encourage plants, insects and larger species to return and thrive. The different species tend to graze on different plants, at different heights, creating a range of mini eco-spheres for a variety of plants, small mammals, insects and microbes. The dung of the large grazing mammals fertilises the earth, restoring it, while their scraping, digging and rootling aerates the soil and turns over seeds, creating more opportunities for diverse life. An underlying idea is to recreate, as far as possible, the environment that existed when Europe was 'wild'. Then the landscape was created and managed by herds of many different, large grazing animals: wild cattle, wild horses, several species of deer, wild goats and sheep and wild boar. (In Holland, they allow animals to die if there isn't enough land to support them, as they would have done in the Ice Age, and they allow the carcases to rot where they fall, creating opportunities for scavengers. The Burrells didn't think the British public would support this much Nature at Knepp.)

When hedges aren't cut back and scrub isn't cleared, thorny plants thrive, protecting more tender plants from the grazers: 'thorny thickets are the forest's cradle.'  Remember that 'forest' doesn't mean a dense, trackless mass of 'closed canopy' trees (that's a wood.) 'Forest' describes a much more open and changing landscape with a mixture of trees, open grass and thickets, through which grazing animals move. It was originally the term for the Norman hunting grounds, hence 'The New Forest.' In such a landscape, filled with every kind of large grazing animal, dense trackless wood never takes hold. Nature, left to itself, both creates opportunities for life and controls the environment that supports it.

Following Vera's ideas, the Burrells released Exmoor ponies onto their land, because they are an ancient breed, closely related to the horses painted on the walls of caves. They also released an old breed of long-horn cattle, to join the deer who already lived in the park. These animals are left to look after themselves. They graze and browse on trees, are fed no grain and seldom need any attention from a vet.



Over time, Tamworth pigs were added, another ancient breed. The pigs surprised everyone by diving into the lake to find mussels -- another example of animals, left to their own devices, behaving in ways unknown to text-books.



Red deer were added to the mix of grazing animals that would naturally be found in any wild British landscape. Do you have the typical image of a red deer in mind? The one where the stag stands on a treeless, bleak Scottish mountainside? -- At Knepp, as soon as the red deer were released, they plunged into the nearest lake and, after many years, still prefer to spend much time haunch deep in water, grazing on water plants -- behaviour rarely seen 'in the wild'.

The Knepp estate now sells wild range meat that is about as organic as you get. Their animals are not injected with hormones to make them grow, nor with anti-biotics to keep them disease-free -- it's not needed because they don't live in unnaturally crowded fields and sheds. They are not fed on grain to fatten them -- they feed, as their ancestors did, on the grass, herbs, flowers and leaves around them.

Tree writes of research by the Economic and Social Research Council which shows that pasture-fed meat is higher in vitamins and 'good fats' and the fatty acid known as CLA which is anti-carcinogenic, strengthens the immune system and is anti-inflammatory. After all, this 'pasture-fed' meat is what fed the northern hemisphere for centuries before farming became industrialised. Winters in the past were often far colder than they are now with little available in the way of fresh fruit and vegetables.


In a fascinating chapter, Tree writes of 'rewilding the soil.'


The vast increase in number and varieties of insects at Knepp, leading to an increase in insectivores and then to an increase in insectivore-vores, was due, in large part, to an improvement in the soil.

It's ironic that modern farming decreases soil fertility. It becomes, as Tree puts it, 'a sterile medium in which plants struggle to grow without artificial fertilisers.' The depleted soil becomes a dust: water and nutrients run through it and it is easily washed away by rain. In 2014 Farmer's Weekly stated that soil depletion was so bad that the UK has only one hundred harvests left.

But at Knepp, they stopped the use of heavy machinery; they stopped ploughing up the earth and cutting its inhabitants to bits. They stopped using expensive artificial fertiliser.

Instead, they let plant material rot where it fell. Their grazing animals liberally dunged the soil as they wandered about, leading to the return of dung-beetles. Dormant, ancient fungi sensed things were turning in their favour and regrew. Earthworms thrived, tunnelling through the earth, dragging vegetation after them. This rejuvenation happened with astonishing speed: thirty years.

Tree quotes Gwilym Wren, a former senior adviser for Natural England. Since degraded land can be restored to health so cheaply and in such a short time, simply by rewilding it, Wren suggested that this be done with a shifting patchwork of land, all over Britain. Several areas of land could be rewilded for anything from twenty to fifty years. During that time, the wildlife would recover in numbers, whether by wildlife you mean microbes in the soil, wild flowers, rare birds and insects or badgers and pine martens.

At the end of the allotted time, the wild area could be quickly returned to agriculture with a newly revitalised, fertile soil -- while another, neighbouring patchwork of land entered into a rewilding phase, providing a new home for the wild life to escape to.

When you think about it, this is very like the ancient 'two-field' system which we're all taught about in school. Ancient farming villages had two fields. The first was planted with a crop (usually grain, such as wheat, oats or barley), while the other was left fallow. Grazing animals were turned into the fallow field, to dung it, and to scrape, dig and rootle about in the earth. The next year, the fields were swopped over. This meant that one field was always rewilding and recovering, ready to provide a crop the next year. An elaboration of this was the three-field system: one field to grow grain, one field to grow beans (which fix nitrogen in the soil) and one field left fallow.

Since ancient farmers weren't scientists, I can only assume they learned this the hard way: by starving when they got it wrong. They learned how to manage better by close observation and remembering what they observed, which I suppose does make them scientists. I've never been a huge fan of the idea that 'ancient wisdom' is better than modern science. Often ancient wisdom is just superstitious pants. But, y'know, occasionally the ancients were more pragmatic, long-sighted and wise than we are. There is no wisdom in paying great sums to turn the land you need to grow your food into 'a sterile medium' requiring yet more vast and expensive amounts of factory-produced imitations of the nutrition that should naturally be in the soil. It's good for the explosives manufacturers turned fertiliser magnates but for no one else.

Wouldn't it be wonderful if we could return the whole of Britain to the two-field system with, say, Herefordshire lying fallow while Gloucestershire is farmed, and Lincolnshire rewilding while Leicestershire is cultivated. And then, after thirty years, SWOP!

This is a fascinating, exciting book. If you're interested in ecology, in preventing flash-floods, in ancient trees, in rare breeds and a hell of a lot more, you'll love it.