Tracks of time: Nepal

Permanence and change: together they provide the pleasing paradox of a walk in the Himalayas.

Here in the Langtang Valley, in the lee of changeless mountains and timeless horizons, the scene shifts hourly, each hundred metres of elevation peeling back another layer of this country's character, and each stage of the trek a novelty in every way but one: the direction - up.

The goal is Kyanjin Gompa, the last village on this three-day plod to the valley's end, at 3,900 metres above sea level. Beyond it lie unclimbed peaks, holy lakes and an impassable wilderness of ice and rock.

That stark landscape is difficult to imagine as you strike out from the cheerful hill town of Syabrubesi, situ-ated at a manageable 1,500 metres and a day's drive north of Kathmandu, the Nepalese capital.

The trail begins as alpine forest, with green paddy fields etching the valley sides and little villages huddling on the level spaces. Troupes of langur monkeys peer quizzically through the foliage and bright pheasants - Nepal's national bird - flee clumsily through the undergrowth. Great beehives hang from the eaves of cliffs while the Langtang Khola river rumbles grandly below. The air is warm, the going easy.

But the gradient soon steepens and each upward step brings change. The flora alters, turning hardier: the forest thins with the air and the trees retreat to sheltered recesses, where they cling on grimly. Soon the valley widens and boulders, the wreckage of an ancient glacial advance, start to outnumber plants and shrubs. The fauna also changes: easy-living cows cede this tougher ground to yaks and the flashy lowland birds give way to ravens and choughs, which hang stubbornly in the stiff, cold breeze.