Doi Inthanon, Thailand’s highest peak with cloud forests

Extensive montane cloud forests.

Extensive montane cloud forests at the higher elevations of Doi Inthanon.

Eighty kilometres southwest of Chiang Mai, Doi Inthanon, Thailand’s highest peak, rises amidst the clouds, its cool, and often cloud-shrouded summit at an elevation of 2565 metres. Much of the mountain’s higher slopes were declared a national park in 1972, with this later extended to an area covering 482 square kilometres.

The mountain’s natural wonders have since become one of Northern Thailand’s major tourist attractions. For a majority of the park’s visitors, up to one million annually, the majestic waterfalls at the lower and mid-elevations are the highlights. Especially at Songkran, the traditional Thai New Year at the height of the hot season, locals flock to the waterfalls to chill out with a picnic, including plenty of beer or whisky.

Indeed, Mae Ya waterfall on the mountain’s southern slope, is undisputedly one of the country’s most beautiful, while three or four others can be listed in the Top Fifty. For many visitors from Bangkok, the flower gardens and greenhouses of the Royal Project at the Hmong village Khun Klang, and the two large chedis at an elevation of over 2100 metres, built in honour of King Bhumibol and Queen Sirikit, are the major attractions.

Magnificent Mae Ya Falls.

Magnificent Mae Ya Falls.

Much of the lower slopes of the mountain is covered with deciduous forest, such as the dry dipterocarp forest which looks rather barren in the dry season. Many nature lovers, however, will be fascinated by the mountain’s upper montane forests, typically found at elevations from 1800 metres up to the summit.

This dense, closed evergreen canopy forest is somewhat similar to tropical rainforest, almost continuous and single-layered, the crowns of the individual trees being dome-shaped. However, it contains far fewer tree species than that, while the dozen or so dominant species belong to such families as the oaks, magnolias, and tea-trees.

Given the clouds,  due to condensation of vapour and low transpiration, the trunks and branches of these trees support an extremely rich epiphytic flora of flowering plants (such as orchids), ferns, mosses and lichens. An extreme example, recorded from a similar montane forest, is a single tree covered with fifty different species of ferns alone.


Dry diperocarp forest on the lower slopes descending to Mae Chaem. Insert: flowering dok din on the torched forest floor in April.

Dry diperocarp forest on the lower slopes along the road descending to Mae Chaem. Insert: flowering dok din on the scorched forest floor in April.

Dry dipterocarp forest with Dipterocarpus tuberculatus covered in fresh leaves, and flowering Ochna integerrima (insert: flowers).

Dry dipterocarp forest with Dipterocarpus tuberculatus covered in fresh leaves, and flowering Ochna integerrima (insert: its flowers).

Upper montane forest is also called “cloud forest” or “montane mossy forest”. On no other mountain in Thailand is the wonderful ecosystem of the mossy montane forest as extensive as here. 

As P.W Richards, an authority on such forests, has remarked, tropical vegetation tends to evoke rhetorical exuberance in those who describe it.

However, few can fail to be impressed by the lushness of the vegetation on top of the mountain, with the many gnarled trees completely covered with epiphytes — bringing to mind the kind of forests depicted in illustrated tales of fantasy.

‘On no other mountain in Thailand is the wonderful ecosystem of the mossy montane forest  as extensive as here.’

It is home to many special plant species, including numerous rare orchids.

It is also a heaven for bird watchers, as with 411 bird species recorded, Doi Inthanon holds Thailand’s record of the largest number anywhere in the country: many of the rare bird species are restricted to here and a few other peaks.

Trees of the cloud forests, their trunk and branches covered with epiphytes.

Trees of the cloud forests, their trunk and branches covered with epiphytes.

Schima wallichii is a common species in the cloud forests. Insert: its flower.

Schima wallichii is a common species in the cloud forests. Insert: its flower.

Yet wildlife on Doi Inthanon has sharply declined over the past sixty years. Mainly due to hunting, many of the larger mammals that once thrived on the mountain — such as elephants and tigers — have disappeared, although gorals, barking deer, and bears still roam the mountain.

What’s more, much of the forests teem with smaller animals, as for instance, the sluggish orange-warted Inthanon or crocodile salamander (Tylototriton verrucosus), Thailand’s only one, while the big-eyed mountain keelback (Pseudoxenodon macrops) thrives in the montane forests. This uncommon snake mimicks the cobra by raising a hood. It is usually regarded as harmless, though it is probably venomous — you better take care not to be bitten! (See the articles Pseudoxenodon macrops in the category Slangen Noord-Thailand and Mock cobras in the category Artikelen-Engels.)

Doi Inthanon is a granitic massif, here and there interrupted by limestone outcrops. It was traditionally called Doi Luang (simply meaning ‘Big Mountain’) or Doi Ang Ka (‘Craw Basin Mountain’ — presumably crows were once common around the basin on the summit.) In 1905, German botanist Carl Gustav Hosséus was the first westerner who hiked to the summit — which he baptized Richthofen Peak in honour of the German scholar Freiherr Ferdinand von Richthofen. During the expedition, he came across a number of Karen villages on the lower slopes (inhabited for many decades). However, he does not mention the Hmong who had settled at higher elevations only years before. The German explorer describes the succession of the fascinating forest types from the valley to the top of the mountain, along with the considerable impact the human settlers have had on the forests. Yet, the upper montane forests at the highest elevations seem have been little disturbed at that time.


Four species of birds often spotted neaur the summit.

Four species of birds often spotted near the summit: 1. chestnut-crowned laughing thrush (Garrulax erythrocephalus) 2. green-tailed sunbird (Aethopyga nipalensis) 3. dark-backed sibia (Heterophasia melanoleuca) 4. chestnut-tailed minla (Minla strigula).

The military constructed a 47 kilometre long tarmac road, Highway 1009, from Chomthong to the summit in the 1970s. From this road, visitors can admire the dense mountain forests, while a number of trails enable them to admire the fringes of this misty ecosystem. The heads of two such tracks are near the control post where Highway 1192 to Mae Chaem branches off the road to the summit. As this is at an elevation of about 1700 metres, it may get chilly, so take a coat or sweater.

To the left of the road is the short Phan Chali Nature Trail (about 400 metres), which passes two impressive towering forest giants and then loops back to the trailhaed. The other one starts opposite. It is a wide, long trail through splendid evergreen forest. Bird watchers may come across some rare species. Understandably, the wet forest floor and numerous rotting tree trunks are home to a myriad colourful fungi. In the rainy season leeches are plentiful, and, though harmless, they may spoil a walk if one starts unprepared.

Yet the ‘true mossy forests’ begin at a higher elevation. Along a trail at about 2200 metres, this type predominates. The start is just above the two 55 metre tall chedis erected in honour of HMs King Bhumibol and Queen Sirikit, right opposite a helicopter landing site beside the mainroad. The three kilometre long Kiu Mae Pan Trail is renowned for its rich bird life, among them many rare mountain species, some remarkably tame — perhaps because they have never been hunted here. It is closed during the rainy season (June-October), and, when opened during the remainder of the year, a guide of the National Park Division of the Forestry Department is required to accompany visitors.

Ascending to the summit, you will see that the vegetation of the exposed and rocky areas along the road is completely different from the mossy forest. This alpine shrub vegetation, however, contains many interesting flowering plants, such as heather species of the family of Ericaceae.

Memorial Inthanonon on the summit.

The memorial of king Inthanon on the summit.

trail on the summit

The elevated board walk of the Ang Ka Trail on the summit.

Flowers of plant from the family Balanophoraceae

Along the trail: futuristic-looking flowers of a plant belonging to the Balanophoraceae family.

A fascinating trail near the summit, known as the Ang Ka Trail, or Michael Trail, is open throughout the year, and is near the summit. A rather large area of the summit, however, has been sacrificed to strategic purposes by the military. From a parking place next to the radar station, steps lead to a memorial stupa containing the ashes of Chiang Mai’s last sovereign monarch, King Inthawitchayanon (abbreviated to Inthanon), who died in 1897. Just behind this, a stone marks the very highest point in Thailand. It’s probably also the country’s coldest spot, as a low of -8°C has been recorded here. The surrounding forest is impressive, since virtually all the trees, shrubs and epiphytes growing here are unknown in the lowlands. Very abundant in the undergrowth is the Doi Inthanon snapweed (Impatiens jurpia), its lovely yellow flowers with orange spurs in bloom during much of the rainy season.

From the stupa, a board walk descends to a small visitor centre with a museum, the place to watch the tame mountain birds that are attracted by the leftovers of the visitors’ snacks. Here, the beautiful chestnut-crowned laughing thrush (Garrulax erythrocephalus), according to Robson’s Birds of Thailand a ‘rather shy species’, will grab a piece of biscuit from your hand. Another beauty, the chestnut-tailed minla (Minla strigula), is also often seen here.


Inthanon salamander.

Thailand's only salamander species is widely known as Inthanon salamander (Tylototriton verrucosus). Beside Doi Inthanon it only occurs on a few other mountains in northern Thailand.

A little down from the centre and oppostite the main road is the head of the already mentioned Ang Ka Trail. This is just 360 metres and is actually a boardwalk through a Sphagnum bog developed on the poorly drained soil of small karst (limestone) depression and through the surrounding mossy forest. Mists sweep through the trees, their tops laden with Old Man’s Beard (Spanish moss), while on their trunk and main branches flourish a dense layer of ferns and mosses.

In the depression, a thick carpet of Sphagnum moss covers the forest floor, with ancient gnarled rhododendron trees arising from it. These dok khulap phan pi (‘Thousand year old rhododendrons’) belong to the rare subspecies Rhododendron arboreum subsp. Delavayi. Besides those at Doi Inthanon, they are only found on one other mountain peak in Northern Thailand. In January and February, they produce large numbers of deep red flowers, a sight not te be missed. (A rhododendron with white flowers is much more common at the higher elevations of Doi Inthanon; it was first described by Hosséus, who named it Rhododendron ludwigianum.)


big-eyed mountain keelback

The big-eyed mountain keelback (Pseudoxenodon macrops) occurs at elevation of 1300-1900 metres.

The forest around the trail is home to many interesting birds. Actually, Doi Inthanon is internationally famous for bird spotting. The rare subspecies of the brilliant coloured green-tailed sunbird (Aethopyga nipalensis), which is often spotted here, only occurs on the top of Doi Inthanon. In the season, it feeds on the nectar of the flowering ‘thousand-year-old’ rhododendrons, but it is also fond of the nectar of the flowers of the Fuchsia grown at the visitor centre. Another bird exclusively living on this mountain top is the tiny, inconspicuous ashy-throated warbler (Phylloscopus maculipennis).

One of the commonest trees of the canopy is Schima wallichii from the tea tree familly; its fallen white flowers with the many bright yellow stamens can lavishly adorn the boardwalk in season. The futuristic-looking flowers of a parasitic plant belonging to the family Balanophoraceae can sometimes be spotted on the forest floor beside the board walk. Amidst the dense mossy forest, you will also come across a small shrine for the spirit of the Royal Thai Air Force pilot, who, some decades ago, died here in a plane crash. The debris of his aircraft  is stored under the spirit house. Some visitors light a cigarette and leave it at the shrine for the pilot’s spirit. It’s safe: in this permanently damp habitat there is absolutely no risk of causing a forest fire.

©Sjon Hauser: text, pictures and maps

Doi Inthanon is internationally famous for spotting rare birds. My pictures of birds taken in the park are of poor quality. My nephew Pim Julsing would certainly enjoy a visit to the mountain. His site is one of the best in the field of bird spotting in the Netherlands and some other countries in Europe (in Dutch). A good field guide for bird watching in Thailand is Craig Robson’s A Field Guide to the Birds of Thailand. For identifying fungi Diversity of Mushrooms and Macrofungi in Thailand (2008) is the best book. To learn more about the trees on Doi Inthanon and to identify some 700 other tree species, consult the excellent illustrated Field Guide to Forest Trees of Northern Thailand by Simon Gardner, Pindar Sidisunthorn and Vilaiwan Anusarnsunthorn. All mentioned books are for sale at Dokmai Garden in Hang Dong: