Well, perhaps ascended would be more correct as the majority of the actual climbing was achieved through the work of the internal combustion engine rather than my own limbs. Doi Inthanon really is part of the Himalayas though; the eastern end of continental buckling caused when India crashed into Asia some 30 million years ago. It's also Thailand's tallest mountain at 2565 metres, and it took almost an hour to drive up the winding roads to the summit.

The 50km bus journey from Chiang Mai to Chom Thong, at the foot of the mountain, was a very reasonable 19 baht. For some unexplained reason, the young ticket collector on the bus had 4 baht's worth of change stuck in his ears - it didn't seem to be because of a lack of pockets and it seems unlikely it was absentmindedness. I was too afraid to ask for more details.

The remaining 50km to the top were altogether more expensive. My faithful Lonely Planet informed me that it would cost just 60 baht to go up and down the mountain, "just hop on one of the songthaews", it said cheerfully. Normally songthaews are crammed full of people - which in turn means they are cheap. As luck would have it there appeared to be almost no other tourists around. Great, the place would be deserted! Unfortunately not sharing the view also means you don't get to share the songthaew fare. In the absence of any other passengers the driver was reluctant to go up, unless, of course, I would pay what he would normally receive from a full compliment of passengers: a staggering 500 baht. I balked at this expense and tried very hard to bargain him down, but he told me that the petrol alone cost him 200 baht. There were many other songthaew drivers around, so clearly market forces should help me out. Unfortunately - all the drivers seemed to be good friends and it didn't look like anyone would be undercutting anyone else anytime soon. I gave in and agreed to pay his exorbitant fee, which was greeted by much smiling and laughing by all and sundry. I felt it would have been rather pig-headed of me to refuse as I was half-way there already, and I didn't relish the prospect of walking. But I felt a pang of guilt as I watched the trail of thick black smoke forming behind us, coughed out by the songthaew engine operating at its efficiency minimum. What an unspeakably selfish act of eco-vandalism I was committing!

My ears began to pop as we ascended into the national park that surrounds Doi Inthanon and its lesser siblings. Most of the mountainside is covered in dense forest, punctuated by the odd hill tribe village here and there. The hill tribes are generally of different ethnic origin to the majority of the Thai population and their villages span and ignore national boundaries. Many are originally from south China, but others are from Burma and Tibet.

Many of the hill tribes grow opium poppies as well as corn and rice. Some grow it for their own consumption, but for others it is a cash crop. Government schemes, within the park at least, have sought to encourage the hill tribes to convert to more politically neutral crops. Occasionally, pillars of smoke can be seen rising from distant misty hillsides - slash and burn agriculture is common amongst some hill tribes.

As the songthaew's engine slowly pulled us up the mountain, the flora began to change. The foot of the mountain is hot and humid and the plants are generally deciduous trees mixed with banana plants and bamboo. Further up, as the temperature drops, rhododendron bushes and pine trees take over. By the time we reached the summit, evergreens and ferns were clearly dominant. Being so high, Doi Inthanon is some 10 to 15 degrees cooler than the surrounding, lower countryside. Consequently it is a small island of cool adapted species - some that are found nowhere else in Thailand (and some, nowhere else at all!).

After taking the obligatory picture of the sign declaring the summit (there being little in the way of a view - only shadowy peaks could be seen through the mist below), I wandered around the forest trails. Apart from the road and the strangely incongruous, but in fact predictable, radar station, the forest rules here. It is almost silent. Thick green moss drips from every tree and seems to soften and absorb sound. It is eerie. All you can hear is the rustling of leaves in the wind, distant birdsong and the occasional humming that marks the path of a passing insect. There is a cool chill in the air and it is surprisingly hard work walking - the air must be thinner here. I started to feel dizzy and lightheaded and after a while I reluctantly left this cool, serene place and began the descent into the heat, humidity, noise and pollution below.

Doi Suthep

Enthusiastically I sped the flat 10 km to the base of the mountain, enjoying the breeze and reflecting that this might not be that bad after all. Then I hit the first incline. Dropping down into the lowest gear I could find on the bike, I began my crawling ascent up the long winding road. My speed was reduced so greatly that even the cooling breeze abandoned me. As I toiled, scooters, belching songthaews and thunderous tour buses hurtled past me. But occasionally there was no traffic and, as I sat in the shade of a tree gulping water and trying to cool off, I could hear birds singing and the almost deafening synchronised chirping of crickets or cicadas. Butterflies were everywhere - small yellow ones fluttered across the shimmering tarmac, blue sparrow-sized ones glided around babbling brooks.

Slowly, slowly I ascended. The gradient was bad, but the heat was worse. Luckily it was a clear blue sky, increasing the heat but limiting the energy-sapping humidity, and the sweating process actually cooled me. I was fast running out of water - I had already drunk three litres and I was down to my last bottle. Cycling, resting, walking, drinking, cycling, cooling off; the 16km passed painfully slowly. Eventually, around an impossibly tight bend, I saw the entrance to the temple, surrounded by the same steaming tour buses and buzzing songthaews. I collapsed into one of the many cafés lining the way and guzzled down several ice-cool drinks.

After recovering a little I walked the 300 steps to the temple proper. It had been worth it - the building shone in the afternoon sun. The bright blue sky formed a backdrop to the golden spurs and red tiled roofs. Green trees stood in the courtyard, with a flash of bright purple blossom here and there. The sound of bells filled the air. Inside the inner sanctum stood a giant stupa covered in gold leaf. It was as if the metal had been made solely for the purpose of reflecting sunlight - it shone a fiery gold.

The temple overlooked Chiang Mai. The city looked distant, hazy and flat; a world away from the calm of the temple. It was here that I bumped into a couple of fellow cyclists who had passed me on the way up. They didn't look half as exhausted as I felt. It transpired that one of them had just cycled from the Burmese border (a couple of hundred kilometres away) and had been cycling in and around Asia for three years! Having said goodbye to my incomparably fitter friends, I coasted out on the bike to begin the descent. This time I was not so quiet - the screech of my brakes broke the silence and my ears began to pop. It had taken me a gruelling four hours to complete the ascent; the hair-raising descent took only 20 minutes! As I write this I can feel my muscles beginning to realise what I put them through today. I think I'll take it easy for a few days; I don't think they'll let me do otherwise.