By David Lewis

NAIVASHA, Kenya, Feb 22 (Reuters) - The drive into Kenya's Rift Valley is a breathtaking climb up over the escarpment followed by a precarious, winding descent down into Naivasha.

Set amid the yellow fever-trees on the shore of a lake brimming with wildlife, Naivasha lures tourists for fishing and bird-watching and farms there churn out tonnes of flowers and vegetables for Europe every day.

I grew up in Kenya and when I was a child this was the first stop on a long bumpy journey to our home on Lake Baringo, in Kenya's arid north. We would have a quick drink here and maybe grab a samosa at La Belle Inn or stretch our legs near the lake.

But this year, just outside the Naivasha country club's gates, I was watching about 1,000 Kikuyu youth wield clubs and machetes on their third day of taunting and attacking hundreds of non-Kikuyus. They had already torched most of the houses.

This was revenge for attacks on fellow Kikuyus after President Mwai Kibaki was declared the victor of a Dec. 27 election which the opposition says was rigged.

It had gone beyond politics. The day before, mobs set up road blocks and were stopping buses, checking the identity cards of those on board and beating them according to their tribe.

Back for the first time in years -- having been called in from neighbouring Uganda to help out as I speak a little Swahili -- I was shocked.

Even the journalists from the Nairobi pack that scrambles across Africa covering conflict or misery did not expect an eruption this deep or violent in Kenya.

"How did it get to this?" everybody asks. The cycles of violence have killed 1,000 people since the election, about 300,000 more have fled their homes, with many returning to their ancestral homelands.

A Kenyan friend who works as a manager for a multinational company in the Rift Valley was hastily sent away to a town where his Luo name would not put him in harm's way.

"They are institutionalising this tribalism," a mutual Kenyan friend told me over a couple of beers. "This is crazy."

BLAME THE MEDIA

Some, especially in the government and the white Kenyan community, have been quick to criticise the media: images of torched houses or rampaging mobs were exaggerated or used out of context, they say.

There have been some melodramatic reports. But watching as thousands of Kenyans packed up their lives, ripping even the roofs off their houses, and crammed them into trucks, it became hard to swallow.

Some objections might also be connected with the hundreds of millions of dollars lost as tourists scrap holiday plans.

For many middle-class Kenyans -- increasingly prosperous and used to treating 'tribalism' as little more than an occasional joke -- what's happening seems mad.

But in the Rift Valley it is very real. I'm British and today I travel around with a Pole and a Palestinian: the resurgent tribalism makes it too dangerous for local staff.

The Kikuyu mob outside the country club scattered when Kenya's army intervened and dispatched helicopters to unleash machine-gun fire above their heads.

A few days later we watched as hundreds from two communities, the Kisii and the Kalenjin, fought a pitched battle because of politics, land and, most importantly, manipulation by local leaders.

Reinforcements were trucked in for one side as the other was fed and watered: then war cries rang out and, armed with machetes, bows and arrows, they clashed over a town that had already been razed to the ground.

Communities that have lived side by side, picking flowers or working in tea estates for generations, have been ripped apart and are joining a flood of Kenyans criss-crossing their country in their tens of thousands.

People follow the talks in Nairobi aimed at reconciliation with a mixture of hope and disgust at the intransigence of leader Kibaki and opposition head Raila Odinga.

But in the end, amid all the extremes and questions of where this will leave a country that, just a few weeks ago, was being held as a beacon of development and democracy, is just fatigue.

"We just want these politicians to agree on something," said a mechanic who only gave his name as Joseph. "One can step down, they could go into a coalition or Raila could just allow the other stay as president.

"Five years is not too long to wait until he can try and be president again. We are just suffering." (Editing by Sara Ledwith)