JARS v60n4 - Botanical Expedition to Northeastern Arunachal Pradesh, India

Botanical Expedition to Northeastern Arunachal Pradesh, India
Harold E. Sweetman, Ph.D.
Devon, Pennsylvania

Exquisite mountains, lush and exotic vegetation, educational opportunities - sounds like a great trip! By my good fortune I had been invited to join an international botanical expedition to Arunachal Pradesh, India, in October of 2005. This remote mountainous region in the high Himalayas borders Tibet and was never previously visited by the famous plant hunters of the past century. Arunachal means "land of the dawn-lit mountains" or "land of the rising sun" due to the high elevation mountains catching the morning light when viewed from regions of India to the south. This expedition would explore valleys and mountains in an area in northeastern Arunachal, east of the Siang River. The Siang River, the largest tributary of the Bramaputra River, is also called the Yarlung Tsangpo in Tibet and the Brahmaputra in the Indian state of Assam. The Siang is a massive river which drains a large area of the Tibetan side of the Himalayas and is one of the reasons the Bramaputra River is the fourth largest river in the world. The Tsangpo Gorges are the deepest on earth and, amazingly, are three times as deep as the Grand Canyon. This sounds unbelievable but if the calculation is based on the elevation of nearby mountains such as Gyala Peri at 23,930 feet (7250m), it is probably true.

Siang River in Arunachal Pradesh
The massive Siang River in Arunachal Pradesh on its
way to become the Brahmaputra River in Assam.
Photo by Harold E. Sweetman

Still one of the most remote areas remaining on earth, Arunachal was previously called the North East Frontier Agency, going back to 1873 when the British stopped free movement in this region. Special government permits are required even today and travel is very restricted. Claiming this region, China invaded India in 1962 all the way to the Brahmaputra River on the Assam plain. The Indian military successfully drove the Chinese back to the traditional Tibetan border region. Recognizing the importance of this border territory, India gave full statehood to Arunachal Pradesh in 1986 and the first trekking expeditions were allowed in 1998.

Tiger leech
Beautiful but pesky tiger leech
removed from this trekker's calf.
Photo by Harold E. Sweetman

Travel in this area is not for the faint of heart or those seeking adventure with creature comforts. Early plant explorer Frank Kingdon Ward in 1924 described Arunachal as "perpetual rain, snakes and wild animals, giant stinging nettles and myriads of biting and blood-sucking ticks, hornets, flies and leeches." Today, research has shown that there are 72 different species of leeches in Arunachal and many are terrestrial. "If the big ones don't get you, the little ones will," was the acquiescent lament while on the trail. Stand still and they climb onto your boot. If you keep trekking, they are poised like a tick on the tips of vegetation ready to attach themselves to you with their suckers. Like an inchworm, it only takes three or four quick leaps and a 3-inch tiger leech is up your boot and on your leg. Needless to say, keeping these rascals outside your tent at night is a mustleave your boots outside. Why would anyone want to travel so far to endure such discomfort? For plant hunters like Kenneth Cox, who organized the expedition, it is the lure of finding new rhododendron species and other unique plants. This international group of botanical enthusiasts included Kenneth Cox (Glendoick, Scotland), Steve Hootman (Rhododendron Species Botanical Garden, WA), Hartwig Schepker (Bremen Rhododendron Park, Germany), Ron Rabideau (Rare Find Nursery, NJ), Tom Hudson (New Zealand and now gardening in Cornwall, England), and Garratt Richardson (Seattle, WA and group physician). Having accompanied Kenneth Cox on a previous expedition to western Yunnan, China, in 1993, I jumped at the opportunity to join this diverse and knowledgeable group of plant enthusiasts.

Suspension footbridge crossing 
the Siang River
Suspension footbridge over 1000 ft. long crossing the
Siang River leaving Tuting at the start of trek.
Photo by Harold E. Sweetman

The large diversity of plants and animals in regions such as Arunachal is due to unique evolutionary circumstances. Plants often evolve into new species when isolated geographically. Islands are a good example of this phenomenon, as well as high elevation mountain areas with deep river valleys. For this reason the entire Himalayan Mountain crescent including Burma, China, Tibet, India, Bhutan and Nepal, has historically lured plant hunters for over a century. On this trip to Arunachal over 40 different species of rhododendrons were recorded during one grueling three-day mountain assent to over 13,000 feet (3940m) in elevation to the Abroka Pass on Mt. Riutala. Comparatively, all of North America has only 25 different species of rhododendrons and the eastern United States has only 19 or 20 species.

Group of Adi porters
Group of Adi porters proudly displaying their large daos - their universal tool and weapon.
Photo by Harold E. Sweetman

As is often the case when exploring remote regions of the world, a great deal of time was spent just getting there. Of the 21 days in India, 11 were spent in transit. The rest of the time was spent in the Siang River Valley, two days each way in four-wheel drive vehicles crammed to the gills with people and top heavy with gear. After leaving Tuting, the start of the trek, we had three days of low elevation slogging through hot and humid subtropical rainforests of wild bananas, bamboo, aroids and other dense vegetation. We were all looking forward to our ascent of Mt. Riutala. Experience has shown that the greatest number of rhododendron species occurs near or above the coniferous zone of spruces and firs. As an added bonus to the fascinating number of ericaceous plants discovered as one ascends, leeches disappear at around 9,000 feet (2700m) elevation. The mounting aches and pains from strenuous hiking as well as the discomforts of high elevation are easily dismissed when everyone is in the "rhododendron zone."

Ridge trail on the way to 
Abroka Pass on Mt. Riutala Prayer flags and stuppa at 
Mankota village
Ridge trail of "rhododendron hell" completely covered with
wet slippery rhododendron roots and trunks on the way
to the Abroka Pass on Mt. Riutala.
Photo by Harold E. Sweetman
Prayer flags and stuppa at Mankota village
on the way to Singa village.
Photo by Harold E. Sweetman

Of the more than 40 different rhododendron species observed on this one ascent to the Abroka Pass, there were some that were truly remarkable and others that one might note for botanical thoroughness only. With the combined knowledge of our group of plant enthusiasts, there was hardly a plant that remained unidentifiable. Just as in Yunnan in 1993 when I witnessed Ken's wide-eyed excitement holding his first Rhododendron sinogrande leaf in the wild, we again found R. sinogrande growing at the same narrow elevations of 9,000-10,000 feet (2700-3000m). Kenneth's "rhododendron finds" for the trip were R. kasoense and R. concinnoides , both rare yellow autumn flowering species which were performing right on schedule for our visit. At low elevation after crossing a footbridge we found R. santapauii , only the second time it has been found after its discovery decades earlier by Peter Cox. There was a big leaf species that both Ken Cox and Steve Hootman surmise might be a new unidentified species. This will require more research and possibly another botanical trip in the future.

R. exasperatum R. glischrum ssp. rude bristles 
on leaves
R. exasperatum with uniquely attractive whorls of leaves
Photo by Harold E. Sweetman
R. glischrum ssp. rude bristles on
leaves capturing the golden sunlight.
Photo by Harold E. Sweetman

Honesty is always the best policy and most of the 40 plus rhododendron species observed on the way to Abroka Pass would not survive in the Philadelphia area. However, we should never give up the quest for good rhododendrons and my two favorite species from the trip were R. exasperatum and R. glischrum ssp. rude . Aside from a great name, R. exasperatum has unique convex orbicular leaves which appear to lack a petiole giving the appearance of whorls of foliage on a very attractive plant. The flowers may not be spectacular but this remarkable foliage effect would be outstanding in the garden any time of the year. The brassy wooly bristles on R. glischrum ssp. rude would also be highly attractive in the landscape as they gather the sunlight. Even if these two species were not adapted to our garden conditions, they could possibly be hybridized to preserve their unique species appearances.

Alpine lakes and 
flora at Abroka Pass
Alpine lakes and flora at Abroka Pass, elevation 13,200 ft., on Mt. Riutala.
Photo by Harold E. Sweetman

After days of rigorous hiking, we finally reached the Abroka Pass on Mt. Riutala surrounded by rich alpine flora. Almost all the plants are prostrate or nearly so with dense mats of plants underfoot and across the rocks. It is impossible to move without walking on treasured carpets of R. forrestii , R. charitopes var. tsangpoense , R. pumilum , R. trilectorum and the completely prostrate Salix lindleyana . Sadly, distracted by great botanizing on top of the world, there is never enough time to rest and savor the moment after so many days of arduous travel. Surrounded by magnificent vistas in all directions, there is a unique spirituality in places like the Abroka Pass that is cross cultural regardless of the Buddhist significance of this sacred mountain. We linger as long as possible but we must descend in time to reach a level campsite at lower elevation before darkness makes hiking extremely dangerous.

Mishmi guide 
perched on the massive tree trunk Porters preparing lunch
Mishmi guide perched on the massive trunk
of a 40 to 50-foot R. sinogrande tree.
Photo by Harold E. Sweetman
Porters burning R. sinogrande wood to prepare
lunch served on giant leaves of the same species.
Photo by Harold E. Sweetman

As director of a botanical garden, I must be somewhat of a generalist and I have developed a great appreciation for the full diversity of plants that one encounters in any ecological habitat. At elevations near 13,000 feet (4000m) we saw Rheum (rhubarb), Astilbe, Thalictrum (meadow rhue), Aconitum (monkshood) and many other familiar genera at lower elevations such as Agapetes, Arisaema, Clethra, Enkianthus, Gaultheria, Leucothoe, Pieris, Vaccinium and other interesting plants too numerous to mention. The educational experience of visiting such pristine ecological habitats and observing the diversity and broad distribution of plants are truly the rewards of botanical expeditions.

Lower portions of Namcha 
Lower portions of Namcha Barwa skirted with early autumn snows.
Photo by Harold E. Sweetman

But it is not just the great diversity of plant life which lures the intrepid traveler. In this remote area one can get a rare glimpse into tribal cultures of these high Himalayas. Arunachal has 25 different tribal groups, speaking over 15 languages. Recent television documentaries highlighted hunters of this area who still use aconite poison on arrow tips. Aconitum is a species of monkshood. Sustainable only due to low population density, most remote villages practice slash and burn agriculture called "jhuming" to eke out a subsistence existence.
With the towering summits of Namcha Barwa (25,531 ft, 7737m) and Gyala Peri (23,930 ft, 7252m) on the Tibet border visible in the distance, it is no wonder that this region is considered an ultimate pilgrimage destination for devout Buddhists. Buddhism is the dominant religion in this region and majestic mountain scenery inspires a profound spirituality. In fact, certain mountains are considered sacred with Buddhist temples as well as numerous chorten and stuppa shrines encountered along the treks. Aside from the porters who were Buddhist, none of the international trekkers practiced Buddhism. However, great reverence and respect was given to all Buddhist traditions. Trekking in early October, so close to the end of the monsoon season, is always risky. Amazingly, it rained on the expedition only twice during the night while everyone was comfortable in tents. All days were sunny without rain or snow. Was it the prayers of the monks at the start of the trek or the careful delivery of personal prayer scarves at the sacred alpine lakes at Abroka Pass on Mt. Riutala that insured this good fortune? One will never know but this was indeed the trip of a lifetime. Namaste.

Harold E. Sweetman, Ph.D., is the Executive Director of the Jenkins Arboretum in Devon, Pennsylvania. He is a member of the Valley Forge Chapter.