Mounting evidence suggests that children's isolation from nature, more than any other factor, is putting them under increasing stress, writes Anna Mundow

We hardly need an expert to tell us that children are not out in the natural world as much as they used to be. The evidence is all around us: in empty woods, fields, river banks and parks. We also know - or think we know - the reasons for this gradual depopulation.

Children are indoors playing in a virtual world of computer games, watching television or doing homework, safe from the human predators that lurk beyond the garden gate. This summer in the US, many of them will spend months not at plain old summer camp but at computer camp or weight-loss camp.

Instead of learning how to build a fire or read animal tracks, they will monitor their intake of calories and sharpen their keyboard skills. As the New York Times recently observed, "The days of free-range childhood seem to be over."

The most noticeable result of that sad fact - childhood obesity - is well documented. But the deeper consequences of the child/nature divorce have been largely ignored.

"We study everything else in child development," says journalist Richard Louv, "but this is the elephant in the room, the most fundamental question, that we have completely ignored. What happens when the child in nature becomes an endangered species? What happens not only to that child but to our species as a whole?"

In his new book, Last Child in the Woods: Saving Our Children from Nature Deficit Disorder, Louv answers that question not only by observing and listening to modern children but also by analysing our relationship with nature and by providing the scientific evidence that shows how vital that relationship is.

There is nothing fuzzy or New Age about Richard Louv. When he talks about Ritalin being liberally prescribed for Attention Deficit Hyperactivity Disorder (ADHD) in pre-schoolers (it is also prescribed for children in Ireland), or about children as young as four taking anti-depressants, he sounds as angry as a soft-voiced man living in San Diego can sound. When he says, "the woods were my Ritalin", he is not elevating himself or his rural Kansas background. He is urging specialists and parents alike to consider the fact that one of the biggest shifts in recent human history may be taking its heaviest toll on children.

"In the space of a century," he argues, "the American experience of nature has gone from direct utilitarianism to romantic attachment to electronic detachment . . . Today's core belief is that nature is in the past."

Paradoxically, today's children probably know more about the Amazon or the Antarctic than they do about the plants or birds in their own neighbourhoods. What they are missing, Louv argues, is the tactile, random experience that is central to child development and mental health. Frank Wilson, professor of neurology at the Stanford University School of Medicine and author of The Hand, agrees.

"We've been sold a bill of goods - especially parents - about how valuable computer-based experience is," Hall insists. "We are creatures identified by what we do with our hands."

Observing that his colleagues find it increasingly difficult to teach medical students how the heart works as a pump, Hall explains that "these students have so little real-world experience; they've never siphoned anything . . . may not even have hooked up a garden hose. For a whole generation of kids, direct experiences in the backyard . . . in the fields and woods, have been replaced by indirect learning through machines. These young people are smart . . . but now we know that something's missing."

If the practical and physical rewards of playing outside in nature seem obvious, the psychological and emotional benefits are more difficult to measure and have therefore been largely ignored.

"It's the old management mantra: that which cannot be counted does not count," Louv says. "But that attitude is changing."

Consider ADHD or Attention Deficit Disorder (ADD). Between 1990 and 1995, the use of stimulant medications such as Ritalin and Dexedrine to treat these disorders in children in the US increased 600 per cent. But the first study to link ADHD and television watching was published only last year by Children's Hospital in Seattle.

"Getting kids out in nature can make a difference," Michael Gurian, a family therapist and author of The Good Son, insists. "We know this anecdotally, though we can't prove it yet."

Evidence is mounting. A recent study in the journal Environment and Behaviour, for example, found that " . . . activities in natural, green settings were far more likely to leave ADD children better able to focus and concentrate". Fine, say critics, but nature is not the Eden it once was. What about the abductions, the murders? Louv argues nature was never a safe paradise. That is why children learn so much from it. "I can't prove that children who spend a lot of time in nature are by and large safer," he admits, "but I'm sure that the hyper-awareness gained from early experience in nature is a positive way to pay attention and - when it's appropriate - to be on guard. We're familiar with the term 'street smart'. Perhaps another, wider, adaptive intelligence is available to the young. Call it 'nature smart'."

In Last Child in the Woods, Louv reveals the mundane facts behind many of the missing children stories that terrify parents - most abductors are family members or acquaintances; most abductions take place in urban or suburban settings - and urges adults to teach children "appropriate trust" instead of fear.

He also suggests five practical steps to parents - from getting to know your neighbours to equipping children with mobile phones. These steps have one thing in common: they all take time, a luxury that most parents - and by extension their children - find to be in short supply.

One child interviewed by Louv in California tells him that between school, piano lessons, soccer practice and homework, she only has a couple of hours at the weekend "to play", while a seven-year-old girl in Florida explains it this way: "Well, you should not stare out the window or dream. You should get your mind on your work because you can never get a college education if you don't."

The main thing that poor, inner-city children and their more affluent suburban counterparts have in common is stress, and when a child is struggling to stay safe on dangerous streets or striving to meet a busy schedule, the last thing they have access to or time for may be the very thing they most need: what child development specialists call "free play".

"Children live through their senses," observes Robin Moore, director of the National Learning Initiative in North Carolina. "Sensory experiences link the child's exterior world with the interior, hidden, affective world. Freedom to explore and play with the outdoor environment through the senses in their own space and time is essential for healthy development of an interior life."

As open spaces shrink in the industrialised world, however, the best most children can hope for is the chance to play organised sports in purpose-built fields or indoor arenas. Thanks to legal restrictions and fear of litigation, even designated natural areas are increasingly off-limits to unsupervised children who want to climb trees, play in a stream or explore.

Last Child in the Woods reveals as much about our attitude to those woods as it does about 21st-century childhood. "For a new generation, nature is more abstraction than reality," Louv writes, " . . . something to watch, to consume, to wear - to ignore. A recent television ad depicts a four-wheel-drive SUV racing along a breathtakingly beautiful mountain stream - while in the back seat two children watch a movie on a flip-down video screen."

The resulting "nature deficit disorder" in both children and adults has produced what Louv calls "cultural autism", characterised by "tunnelled senses, and feelings of isolation and containment. Experience, including physical risk, is narrowing to about the size of a cathode ray tube or flat panel . . . "

Charting that bleak landscape, he wonders what it means to lose the fundamental senses and skills that shaped us as human beings and considers what we will have sacrificed when the child in nature, now an endangered species, finally becomes extinct.