In July 2002 John and Hilary Birks visited the small Himalayan country of Bhutan as part of an Alpine Garden Society Expedition led by Dr Bill Baker, Royal Botanic Gardens Kew. The major aim of the 2 week visit to north-west Bhutan was to explore the alpine flora and vegetation of the area. However, to reach the alpine zone above about 3800 m altitude, several days had to be spent trekking through the magnificent middle and upper cloud or "mist" forests of north-west Bhutan.

Bhutan is a small and rather isolated country about the size of Switzerland lying between Nepal, Sikkim, and India. Its highest point is 7554 m and northern Bhutan lies on the eastern end of the great Himalayan mountain chain. About 650,000 people live in Bhutan where the average annual wage is only $650 a year. Bhutan still has over 70% of its natural forest intact and it is probably the least spoilt country in the Northern Hemisphere. The number of visitors is limited each year and each visitor has to pay $200 a day!

Floristically Bhutan is very rich with over 5000 species of flowering plant. It is the only Himalayan country with an up-to-date flora, thanks to the Royal Botanic Gardens Edinburgh 27-year project that resulted in the nine-volume Flora of Bhutan edited by David Long and the late Andrew Grierson.

Plant list from the Bhutan Expedition

Photo Gallery

After flying into Poro airport, perhaps with the most unique airport terminal in the world, we spent three days botanising and acclimatising in the Thimpu, Dochu La, Taktsang, and Cheli La Pass areas, including visiting the spectacular cliff-side monastery at Taktsang. We then trekked for 10 days on the Jhomolhari trek starting at 2530 m at Drugyel Dzong and climbing to 4870 m on the Ngile La pass and returning via Shodu and Barshong to Thimpu. Sonam Wangchuk was the local Bhutan trek leader.

Between about 2530 m and 2800 m, the landscape is intensively cultivated with rice fields and buckwheat cultivation. From about 2800 m to 3200 m, middle cloud forest with Quercus semecarpifolia, Tsuga dumosa, Rhododendron arboreum, and Magnolia globosa is dominant with a wonderful range of forest herbs and epiphytic orchids, bryophytes, and ferns including Meconopsis paniculata, Arisaema griffithii (left), and Pleione hookeriana. Between 3200 m and 3800 m we walked through upper cloud forest of Abies densa, Betula utilis, Juniperus indica, and J. recurva. These forests have a dense growth of epiphytic lichens, including the large grey pendulent Usnea longissima. Slipper orchids are a spectacular feature of these forests with both Cypripedium himalaicum and C. tibeticum.

Tree line is about 3800 m and our third night's camp at Jangothang (4030 m) was already in the alpine zone. Low-alpine Rhododendron lepidotum heath dominates between about 3800 m and 4200 m and its lower boundary lies where there are about only 100 days a year with mean temperatures above 50C. Besides R. lepidotum, the low shrub Potentilla arbuscula is common. The recently described orchid Bhutanthera himalayanse was found in this heath.

Above Jangothang, the valley of the Twin Lakes at 4200 m provided a wide range of middle alpine grasslands dominated by Primula sikkimensis. Besides P. sikkimensis, we also found P. capitata, P. bellidifolia, P. sapphirina, and P. primulina in these grasslands, along with the beautiful Gueldenstaedtia himalaica and the remarkable hemi-parasitic Pedicularis bella, P. siphonantha, and P. oederi ssp. branchiophylla.

The high passes at Ngile La (4870 m) and Yale La (4860 m), the slopes above Twin Lakes, and the areas around Lingshi provided a range of high-alpine habitats, including wet grasslands, open grasslands, rock outcrops, and cliffs. Primula tibetica (left) and P.waddellii were striking plants in damp turf, whereas Draba oreades formed bright yellow cushions on cliffs. The stoloniferous Saxifraga pilifera occurred locally in open ground, whereas S. caveana and S. andersonii were confined to high cliffs. High-altitude screes support some of the most spectacular Himalayan plants, including the dimunitive Corydalis cashmeriana, the almost invisible Fritillaria delvayi, the "cotton wool" or "snow ball" Saussurea gossipiphora, the "scree acrobat" Eriophyton wallichii, the amazing scree Meconopsis discigera, and the spectacular gigantic Himalayan rhubarb, Rheum nobile (right, photo: Bill Baker) with its massive outer "greenhouse" of bracts that protects the flowers from cold, wind, and rain.

As we were trekking in the monsoon season, the time of rain and low cloud but when the alpine plants are in full bloom, we did not see as much of the high Bhutan mountains as we would wished. Some pictures are included to give an idea of the terrain, for example the Yale La pass with a local Bhutan boy, a yak farmer's yurt (tent), the trek in progress at 4400 m, John Birks crossing a very cold(!) river at 4500 m, our camp at Shodu at 3940 m, Paro Zong and the Poro valley, and the combined Alpine Garden Society expedition and their Bhutan trek leaders and helpers.

In our two-week visit to Bhutan we found just above 500 species of vascular plant. We are very grateful to John Richards (Newcastle), Magnus Lidén (Uppsala), Ian Hedge, Eona Aitken, and Mark Watson (Edinburgh), and Philip Cribb (Kew) for help with plant identifications and to Bill Baker (Kew) and Sally Henderson (Natural History Museum, London) for their superb leadership.