Midsummer Madness

The last time I met a group of strangers in a layby it was 1989, the second Summer of Love. Under-age and under dressed, we were trying to find a field with a rave in it.

Over 20 years on, I'm doing something a little more age-appropriate but just as fun: meeting outdoor swimmers, pulling on a swimsuit and jumping in a river.

After making friends in a heartbeat – standing semi-naked by the side of a B-road does accelerate the bonding process – we pick our way across a field. We're quite a sight: barefoot, red hats, wet suits and goggles.

Chat is excited but a little nervous. How long will the swim take? How cold will the water be? Will the current help us? What happens if we want to get out early? We pass a group of picnickers, flushed pink from the sun and the empty bottles of wine littering their rug. They wave and shout words of encouragement.

Soon we're at the riverbank. Here in Oxfordshire, we are around 40 miles from the source of London's great river. The water is brown-green, clean and sleepily slow-moving, the bank lined with lush shrubbery.

I hop down and into the shallows, surprised to feel sand between my toes. The water is colder than I expected but as soon as I dive under and stretch out, my shivers pass and it cools me down. I am at the front (it won't last), cleaving through the water at a gentle pace. No-one is racing: strokes are languid as we drink in the surroundings. It's exceptionally peaceful, just the lapping of the water, murmuring chat and the occasional whoop behind us as someone enters the water.

Reeds and leaves become entangled in my fingers. Ducklings wobble past. And every five minutes a large boat looms into view. It makes me feel very small bobbing at water level as they cruise past.

After a kilometre or so, I'm starting to chill. Most people are in sturdy wetsuits but my new-found friend and I are in skimpy swimsuits (it was only a last minute change of heart that made me leave my bikini at home). So we get out at a stretch of sand and walk back to the parked cars. Our goose bumps are soon warmed by the afternoon sun.

We catch a lift to the end of the swim, at the village of Shillingford a mile away, and await the swimmers (pictured, above – that's me by the barge wrapped in a woolly grey cardigan).

Soon, red hats appear around a bend in the river. They reach the bank and clamber out into awaiting towels, beaming with the joy of exertion, relief and pride. I haven't enjoyed a Saturday afternoon this much in years.

Storm in a treehouse

Koh Rong is a tiny island off Cambodia's south coast – 15km of pristine jungle and pale sand so soft it feels like icing sugar between your toes.

A few hundred people live here, their corrugated huts lining the beach on the island's eastern edge. Their children attend a local school. They fish. And they provide food and drink for the small groups of scuba divers who explore Koh Rong's emerald waters.

Until recently, few tourists visited this beach. But in the past couple of months, a handful of wood and thatch bungalows have appeared among the trees. And if you keep walking, round a tiny headland, you reach few more, including a magnificent treehouse, two storeys high with vertiginous steps, waves lapping at its feet and heart-stopping views out to sea.

This is where we spent the night.

The treehouse was built by Nuch Ros, a beautiful, bubbly girl from Sihanoukville across the water, and her Turkish husband, Bora Ozturk (she fed us hot sour soup to revive me after the bumpy crossing). It has a large bed with a mosquito net, open sides to catch the breeze, even a shower. We threw down our packs and dozed to escape the searing midday sun.

A word on that: it is a hardier traveller than I, I have discovered, who braves Cambodia on the cusp of the rainy season. Most days it reaches 40 degrees, and it is so humid that I swear I sweat even in the shower. I am always, always hot. A fan is a must, air-conditioning preferable, otherwise sleep (in the loosest sense) involves lying in one position long enough for the sheet to soak, before rolling onto a drier patch and repeating.

The rains are on their way, though. Most evenings, thunder rumbles like timpani and lightening forks through the clouds, sometimes followed by a short downpour that cools the air momentarily.

But that night in the treehouse, there is no relief. We are sweating and fanless (the generator is turned off at 9pm). We watch three storms over the mainland, praying for them to reach us, but instead, the air is as thick as noodle soup and the surf beneath us turns listlessly. Sleep is impossible.

Suddenly, a light breeze blows across me. It is almost imperceptible, but I sit up nonetheless to feel its effect on my body. It slowly picks up, and soon my wet skin is drying, the mosquito net is billowing gently and the mercury is falling. I am pathetically grateful.

It doesn't take long to stiffen and minutes later, an empty water bottle blows off the window ledge and lands with a clatter on the floor. Suddenly, lightening fills the entire room, thunder rumbles angrily and the rain comes down.

We're now wide awake. The mosquito net has come loose completely, but I tuck it back under the mattress. It's a pointless exercise as it is whipping around us like a main sail in a gale. A towel and a bikini, tied securely to the balcony, are whisked away into the night. Rain is slicing through the open windows, and the sea is roaring beneath us. Thunder claps deafeningly directly above our heads.

I point out that the treehouse, barely two months old, hasn't yet weathered a rainy season. And suddenly we are laughing uncontrollably, tears streaming down our faces, hysterical with relief, excitement and fear that our treehouse is going to collapse into a heap of sticks.

The storm continues at this intensity for over half an hour. We've stopped laughing, we're cold and wet and we just want it to end. Finally, after a few false alarms, the wind subsides, the mosquito net hangs loose again and I fall into a deep, cool, exhausted sleep.

Living off the land

The tribal people of the world don’t have much of a voice. But journalist Joanna Eede has been collecting their extraordinary stories. She has spoken to Bushmen in Botswana, Amazonian Yanomami and Canadian Innu, among others, about their lives, homes and beliefs.

“This is our land. Do only people live here? No, there are also monkeys, even bears. The land is for everyone, men, animals and plants. The land is full of the spirits of our forefathers, it is a reciprocal relationship. The land is for our men of today and for our children.” So say the Asháninka tribe in Peru, echoing the beliefs of tribes the world over.

These people inhabit some of the most remote corners of the earth: tundra, sea-ice, mountains, deserts and prairies. They have done for thousands of years. “The affinity with their homelands is reflected in the names tribal peoples call themselves,” says Eede. “They are the savannah people, the people of the headwaters, the people from the wild pig place.”

“We did not think of the great open plains, the beautiful rolling hills, the winding streams with tangled growth, as ‘wild’,” says Luther Standing Bear, an Oglala Lakota Sioux. “Only to the white man was nature a ‘wilderness’ and only to him was it ‘infested’ with ‘wild’ animals and ‘savage’ people. To us it was tame.”

Each tribal society is unique. But most share the belief that man and nature should live together – and that a long-term attitude to the caretaking of the planet is vital. “The Iroquois of North America always consider seven generations ahead in their decision making,” says Eede.

We can learn from these wise people, who tread lightly and lovingly on the planet. "Only we, the indigenous people, know how to protect the forest," says Davi Kopenawa, from the ancient Yanomami tribe in the Brazilian rainforest. "Give us back our lands before the forest dies. It is dangerous to abuse nature. The sky is full of smoke because the napë, the non-Indians, are logging and burning our rainforest. The rains come late, the sun behaves in a strange way. The lungs of the sky are polluted. The world is ill."

This week, indigenous people in Brazil are threatening violence after a successful tender for the rights to build a giant hydro-electric plant on their ancient land. "Indians will be forced to kill the white men again so they leave our lands alone," says Kayapó leader, Raoni Metuktire.

We can also learn from their philosophy on life, too. "The desire for possessions is destructive," says Davi Kopenawa. "Nothing that can be bought, or sold, has any real meaning. Possessions are looked upon as symbols of advanced humanity, yet they disappear with the wind. All they do is cloud the mind and pollute the soul."

What can we do? Tell their stories, the tribal people say. "You have seen with your eyes what is happening here," says a Bushman in Botswana. "Go and tell people what you have seen. What would make us happy is if we have the rights to stay on our land."

Last Sunday, a glamorous gathering of actors staged a one-off benefit in London, performing readings from Eede's book, We Are One, which was written for the charity Survival International to mark its 40th anniversary. Julie Christie and Gillian Anderson shared a stage with Derek Jacobi and Mackenzie Crook. Sadly, Colin Firth didn't make it...

Should we care that tribal people are being forced away from their land and livelihoods? "Yes, if we believe that taking other people's lands – and so destroying them – should not be tolerated," says Survival International director, Stephen Corry. "They teach us that price and value are not the same things, and that community can be more intelligent and humane than government."

Or, as Cecilia Mitchell, a Mohawk in the USA puts it: "Different people, different ideas and different beliefs make life so much more interesting.”

Photographs, from top: Mike Goldwater, Grenville Charles, Bruno Morandi

Brief Encounters: ticket

Settled by the train window, the sun streaming in, the elderly man reminded me of a character in a Graham Greene novel: smart hat, straight back, distinguished nose. He was heading, via London, for the coast. Where, I asked? "Brighton. Or Weston-super-Mare. I don't know yet," he said, with admirable free-spiritedness.

"I remember the golden age of steam," he said to no-one in particular. He tried to get a small boy interested in the semantics of the albatross insignia on his uniform, but all he wanted to do was spot Wembley Stadium.

I tried to buy a ticket but the inspector's machine was broken. The man flashed his free pass – "43 years on the railways got me this," he said. He offered to escort me to the ticket gate to back up my broken machine story. But when we pulled into the station, there was no barrier.

He looked concerned, and for a moment I thought he was going to march me to a ticket desk. But then he cracked a smile: "Good job his machine was broken, eh? And to think, I had to work for my free trip." And he shuffled off across the concourse.

Eruption in Iceland

Icelanders rarely forget they live on a groaning, fiery land-mass astride two of the earth's giant plates, the Mid-Atlantic Ridge (pictured above, the plain caused by the plates pulling apart). But in case they do, a volcano erupts to remind them.

Last night's eruption happened not from a snow-capped crater but from a crack in the earth about 1.5km long, near the Eyjafallajoekull glacier. If it erupts again – and a relatively small eruption like this often precedes a bigger one – the glacier could melt, causing devastating floods. Worse, nearby is Katla, one of the country's largest, most dangerous volcanoes. When there is activity nearby, it often starts to move.

Even in a country used to volcanic activity, it's exciting. When they heard the news, young men left their Saturday night beers to jump into 4x4s and head off for a closer look. All the roads were blocked by police cordons.

How do Icelanders feel about their volcanoes? Greipur Gíslason, one of the organisers of Iceland's second design festival, HönnunarMars – the reason I am here – says volcanic eruptions, unless they are life-threatening, are reassuring. "It's really good," he said this morning, wearing the smile of a secretly proud father whose naughty child has just come top of the class. "It reminds us our little island is working properly."

"The earth has reminded us that its creation is still going on, and that we are not its creators," Iceland's president, Ólafur Ragnar Grímsson, told us today, as we sipped white wine at his home outside Reykjavik. "These ever-present, but unexpected events have a strong influence on the mindset of the country."

"We're excited," a young woman told me. "Katla has been sleeping for too long. Her last eruption was nearly 50 years ago so she is behind schedule." (Volcanoes, by the way, are gender neutral, but the most powerful have female names).

I experienced some of Iceland's awesome energy yesterday on a trip to see Geysir, the hot bubbling spring that erupts every 15 minutes or so (below).

It was awe-inspiring. But I fell in love with the tiny bubbling spring nearby...

I swam in an outdoor pool heated by geothermal energy. And I've showered every morning in piping hot water from the ground. On my flight from London, I sat beside a man who sits on the board of an Icelandic renewable energy company. The country produces more energy than it needs, he told me, but it doesn't know what to do with it. I hope they find a solution: if they do, Iceland will become very rich again.

Brief Encounters: swimmer

In the last few years I've swum in an inky black lake in upstate New York (where I dared not put my feet down for fear of monsters); in a Scottish loch so cold I thought I would have a heart-attack (but didn't fear monsters – whoever heard of a monster in a Scottish loch?); and in too many bathtub-warm Indian seas to mention. It soothes, strengthens and regenerates.

But my most memorable outdoor swim was two springs ago. I extended a flying visit to Munich by one day and jumped on a train bound for Starnberger See – a glorious lake 40 minutes from the city. I found a patch of grass among the trees lining the shore, stepped gingerly down the slippery wooden steps into the water and kicked off.

In a heartbeat, the tension in my shoulders lifted and the heart-ache engulfing me at the time subsided. I felt nourished. "Swimmers often feel that in water they are truly 'in their element'," writes Kate Rew, author of Wild Swim, founder of the Outdoor Swimming Society and friend, "and in lakes this is somehow enhanced. They offer the chance for muscles to stretch out and glide for miles, but they also nurture a different kind of wellbeing – that of the heart, soul or psyche."

Back on the bank, as I lay there drying off, a woman in a tiny towel approached the steps. She let the towel fall away revealing a white bikini, dipped an elegant toe into the water and jumped in. She had the figure of a race horse – tall, lean and toned – and her skin was deeply etched in soft, honey-coloured wrinkles. It was the most wrinkled body I'd ever seen. She must have been at least 70.

Yet she looked remarkable. She seemed comfortable in her skin the way so many older women aren't. I bet she swam every day. "When I'm that age..." I promised myself. And I turned my face toward the sun.

Brief Encounters: Pick-up

I’d never been to the US before, so I’d never met anyone from Alabama – I don’t think they give them passports. “You girls ever been in a pick-up truck?” he asked. We giggled.

His name was Chip. I still don’t know whether that’s short for anything.

He took us fly fishing, me and Caroline, my oldest friend. I never really got the hang of it. Besides, I was too fascinated with Chip: he had everything a man needed for a day’s fishing: rod, bait, book, cool beers and a padded thermal sleeve to go round them. I've always envied that sort of simple self-sufficiency.

Caroline and I were visiting a friend on the coast in Maine. That night, with no catch, the four of us ate at Mable’s Lobster Claw. Talk turned to women. Apparently, the girls of Maine weren’t up to scratch. What about Internet dating, we suggested. “I’d be lettin’ maself down.”

A few days later, we drove round to say goodbye. The pick-up was outside, a pair of trousers draped over the back. It was dark, the deep black you get in the country, and the hiss of crickets filled the air. We banged on the veranda door, and eventually he appeared, a beer in his hand snug in the thermal sleeve. “I’m goin’ to Portland, gonna get me a girl,” he winked. “Ya’ll have a naace trip home.”