Arts, Books, Environment, Nature

Book Review: Hedgelands

LITERARY REVIEW

Intro: Hedges are humble habitats that are a lively host to much wildlife – a secret safari providing a plethora of environmental benefits

THE humble and often-neglected British hedge, is described by author Christopher Hart as “an incredibly porous and self-sustaining feature of our countryside . . . one of the happiest accidents in human history.” It hums with bees and butterflies, is a rich haven for insects, birds, hedgehogs, shrews, voles, and bats, and also acts as a windbreak, stock fence, flood defence system, and an environmental barrier against soil erosion. The RSPB agrees; its research shows that hedges may be supporting up to four-fifths of our woodland birds, half of our wild mammals, and a third of our butterflies.

Hedges have been a feature of the British landscape since the Stone Age. The original ones were “dead hedges”, made from piles of branches and brushwood collected from cleared areas of woodland.

As the wood rotted, it was swiftly colonised by fungi and insects. Passing birds excreted seeds from trees and shrubs – such as hazel, oak, ash, hawthorn, dog rose, blackthorn, and bramble – which soon started sprouting in among the dead wood. From there, a living hedge was born. (A hedgerow, if you were wondering, is a hedge that includes features such as banks, trees, walls, fences, or gates.)

Our ancestors soon learned the best way to deal with an unruly hedge: by cutting half-way through a rising trunk and then to lay it back into the hedge sideways. In time, this creates a barrier so dense and tough that it can even hold back an amorous bull trying to get into a field of cows.

Yet as Hart rightly points out, these ancient hedges are much more than just a physical barrier. They mitigate flooding and soil erosion and give many animals an invaluable source of shelter from precipitous conditions. A hedge will protect smaller birds and mammals from predators like crows, magpies, sparrowhawks, and foxes – a dense hedge is difficult for predators to access and manoeuvre. This “narrow but incredibly complex ecosystem” is also an abundant source of food for wildlife, providing hips, haws, sloes, and blackberries for them to feast on.

Many of the countryside hedges we see today pre-date the Georgian era, some even being Anglo-Saxon. In a county like Devon, where the land is suited to sheep and cattle and less likely to be ploughed, at least a quarter of the hedges date back to Norman times.

TWO

THERE are strong regional variations in Britain’s hedges. In the Midlands, traditionally cattle country, hedges tend to be mainly hawthorn, which is an excellent barrier to bullocks. The high rainfall in Wales and Ireland is just the thing for blackthorn, which happens to be a handy plant for snagging and restraining sheep.

The Somerset Levels typically have hedges made of osier, a small willow tree, while in Kent and Worcestershire you’ll find hedges of beech, poplar, and elder which tend to grow tall to protect prized orchards from the wind.

By 1820, there were 700,000 kilometres of hedges in England (and many more in Scotland, Wales, and Northern Ireland). Today the figure is 400,000 which still sounds impressive, but many of these hedges are so degraded that they have become “little more than a blunt, dwarfish lined of scarred and wind-scoured stumps”, as Hart writes despairingly.

On arable land, hedges are often seen as an obstacle for tractors, while on pastureland, farmers find it easier to put up a barbed wire fence than have a hedge separating livestock. Hart is sympathetic to farmers, who are not “the cartoonish villains of the countryside but, rather, hard-pressed food producers just trying to stay in business”.

But there’s no denying that replacing a bountiful hedge with barbed wire is a disaster for wildlife, which results in “no wild foods, berries, nuts, wild greens, or herbs . . . no shelter or habitat for birds and mammals, [nor] beneficial pollinators and insect predators.”

THREE

MOST of the damage to the country’s hedges was done from the 1960s onwards when, incredibly, government actually offered subsidies for their removal. After 1973, the EU’s damaging Common Agricultural Policy was even more zealous in paying farmers to destroy ancient hedges.

If all this sounds depressing to anyone who cares about the countryside and its wildlife, Hart offers some practical solutions. Many hedges in private gardens are a single variety, like privet or beech; the author suggests that you rewild yours, by weaving honeysuckle and brambles through your hedge, making it far more attractive to insects.

And if you leave a little verge around the bottom of your hedge, all sorts of wildflowers might pop up, from orchids and buttercups to cow parsley and bluebells.

Above all, we are urged to cherish our existing hedges. Instead of spending a fortune on planting millions of new trees, which Hart says are “of low ecological value”, he would like the Government to allocate a fraction of that money to restoring hedgerows.

With better management of hedges, “we might not need to worry so much about insects disappearing, bird numbers falling or our targets for carbon capture. Our lovely native hedgerows would do much of the work for us, if we only look after them.”

Hart has his own 300 yards of “beautiful, unkempt, pullulating hedgerow” at his home in Wiltshire, and he has seen for himself how endangered birds such as redwings and fieldfares will eagerly flock to a hedge which provides nutritious wild berries for them.

Christopher Hart has written an eye-opening and inspiring book which will leave the reader with a deep appreciation of these wonderful habitats – and perhaps a desire to create their very own hedge. As he says: “You don’t need to go to the Serengeti to see amazing animals. You just need a good thick hedge.”

Hedgelands by Christopher Hart is published by Chelsea Green, 208pp

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Science

Questions of Science: Plant poser

Q: Did all the oxygen in Earth’s atmosphere come from photosynthesising plants? If not, where did it come from?

WITHIN the Earth’s crust, oxygen combines with all the most common atoms to form water, rock, organic compounds and almost everything else around us. Spontaneous free oxygen is about as likely as finding round rocks perched on steep slopes. Such rocks would imply that something had pushed them uphill more strongly than they could roll downhill.

Similarly, any free oxygen about us has been torn from its compounds with more than its bonding force. And that is a lot of force that only a few things are able to produce. Ionising radiation, such as X-rays, can do it, but there is little of that about. Visible light does it laboriously, step-by-step through photosynthesis, the only process that could release the level of oxygen that we see about us. That amount is calculated to be in region of 10¹⁵ tonnes.

How much oxygen plants actually produce is another matter entirely. The chloroplasts used by plants to photosynthesise are thought to have originated as symbiotic cyanobacteria. So, in effect, all our oxygen came from photosynthesising bacteria. Hence, practically all the atmospheric oxygen is of biological origin – and is not from plants but cyanobacteria.

These single-cell organisms, which were present on Earth more than 3.5 billion years ago and pre-date plants, were initially responsible for all oxygen production and are still responsible for more than 60 per cent of current oxygen production.

Cyanobacteria come in many varieties and are sometimes called blue-green algae, although they are not really algae. A species of cyanobacteria present in the ocean, Prochlorococcus marinus, is both the smallest photosynthetic organism known and the most abundant of any photosynthetic species on the planet. It was only discovered in 1988.

Previously Questions of Science: Free the atoms

Science-in-motion: a series of short articles following topics in science.

. Biodiversity

This measures how much variety there is between all the different species of life on Earth, from single-celled bacteria through insects to blue whales, the largest known animal ever to have existed. Biodiversity also describes the genetic diversity within a single species, or even the diversity of ecosystems like wetlands and forests.

Around 1.75 million species of living organisms have been identified on Earth so far, mostly small ones like bacteria and insects, and estimates suggest the true number could be as high as 100 million. But in recent centuries, there has been a rapid increase in the rate of species extinctions due to human activities such as habitat destruction for farming.

Between 1500 and 2009, international organisations documented more than 800 species becoming extinct, including the Javan tiger that died out completely in the 1980s, but the vast majority of disappearances probably go unnoticed. Conservationists grade the vulnerability of species according to a continuum scale that runs from ‘extinct’ to ‘least concern’.

Biodiversity is of huge significance. The development of new medicines, for example, is inhibited during rainforest destruction, of which many tiny organisms are either destroyed or not even previously discovered.

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