Tibet: A Medical Fountainhead
The Tibetan Plateau towers over the central part of the continent of Eurasia. It is bounded by the Himalayan mountain chain in the south and connected with the Altyn Tagh and Gangkar Chogley Namgyal mountains (Ch: Qilian Mts.) in the north. Its western region merges with the Karakoram mountains and its eastern reaches slope downward more gradually with the Minyak Gangkar and Khawakarpo mountain ranges
The Tibetan Plateau is the highest and largest plateau on the earth, occupying an area of more than 2.5 million sq. km. Its average elevation exceeds 4,000 m (13,000 ft), and many of the peaks reach beyond 8,000 m, Mount Everest at 8,848 m being the world's tallest mountain. In fact, Tibet is home to all 14 of the world's peaks greater than 8,000 m (26,259 ft.) in elevation. The Tibetan Plateau consists of a variety of landscapes ranging from lunar vistas in some parts of Southern Tibet to lush and thick tropical forests in Eastern Tibet. The plateau stretches from 500 m to 5,000 m from its edges to its hinterland; within the two extreme values lies an infinite combination of climatic elements. Factors such as the mean temperature which ranges from -8¡C to 20¡C, the annual rainfall which spans from 25 mm to 4,000 mm, and total solar radiation which varies from 110 cal/cm2/year to 210 cal/cm2/year are just a few variables that contribute to the myriad possibilities for life on the plateau.
When speaking in ecological terms, Tibet can be divided into three broad zones:
1) humid tropical and subtropical southeast where the oriental and paleoarctic floras and faunas meet
2) broad valleys of the Yarlung Tsangpo and Indus which are bordered to the south by the Himalayas and to the north by the Mt. Tesi (Kailash) range and Nyenchen Thangla ranges
3) frigid alpine and desert steppes of the Chang Thang (Northern Plateau), much of which lies above 4,500 metres.
Tibetan Plateau to become a crucial centre for the composition and differentiation of mountain species in the world, especially of high-altitude flora and fauna. The Tibetan Plateau continued to form throughout the quaternary period, when a horizontal distribution pattern of ecosystems became established. These included zones of tropical rainforest, subtropical evergreen broad-leaved forest, sub-alpine evergreen needle-leaved forest, alpine shrub-meadow, high-cold steppe, and high-cold desert.
The Tibetan Plateau is the storehouse of innumerable species of unprecedented value to the balance of life worldwide. The plateau's distinctive geological evolution, landscape, climatic variation, hydrological systems, and unique atmospheric circulation patterns, have been scientifically proven to influence the health and wellbeing of the entire planet. The biodiversity of Tibet is only presently beginning to be viewed as an important issue. The World Wide Fund for Nature states:
The conservation of biodiversity in Tibet will have a strong impact on China, South Asia, and Southeast Asia. What takes place in Tibet also affects global biodiversity and the life of people throughout the world.
With its huge landmass, it is no wonder that Tibet's varied array of ecological niches possess such diversity making it the last sanctuary for some of the world's rare plant and animal species. This is primarily due to Tibet's long period of isolation and the centuries-old protection provided by its sky-tapering, majestic mountains. The natural protection is further strengthened by the Tibetan Buddhists' ethos of living in harmony with nature. In olden in days Tibet there were no specially-designed nature reserves or parks as the modern world today demands.
Captain C. Rawling in his book The Great Plateau published in1905 says, "Almost from my feet away to the north and east, as far as the eye could reach, were thousands upon thousands of doe antelope [Tibetan antelope] with their young...There could not have been less than 15,000-20,000 visible at one time." British plant hunter and explorer, Kingdon Ward, who made several surveys in Tibet, wrote before the First World War, "I have never seen so many varieties of birds in one place, one great zoological garden."
The Diverse Display
The vast land surface of the Tibetan Plateau has wide climatic variations caused by the unique plateau atmospheric circulation system and the great difference in elevation. Such unusual natural conditions give rise to diverse natural habitats for complex species of flora and fauna. The areas of eastern and southeastern Tibet receive monsoon showers during the months July to September and have abundant plant and animal species, many of which are rare and endangered.
The plateau is the differentiation centre for Rhododendron, Primula, Saussurea, and Pedicularis; there are altogether 400 species of Rhododendron alone, which accounts for about 50 per cent of the world's total species. Many endemic plant species such as Circaeaster, Himiphrogma, Chionocharis, Milula, Cyananthus, Leptocodon, Maharanga, Pegia, Chamasium and various others are found on the Tibetan Plateau.
According to Wu and Feng (1992) the Tibetan Plateau is host to over 12,000 species of 1,500 genera of vascular plants, accounting for over half of the total genera found in China. There are over 5,000 species of 700 genera of fungi, accounting for 82.4 per cent of China; additionally, 210 species belonging to 29 families of mammals account for 65.90 per cent of the total families found in China.
Forests on the Tibetan Plateau are largely found in eastern and southeastern regions. The lushest forest cover is found in the Namchakbarwa region, where the Yarlung Tsangpo river turns to flow into India as the Brahmaputra. In eastern and southeastern regions of Tibet receiving the monsoon Ñ forest grows up to an elevation of 4,100-4,500 metres. A mixed coniferous and broad-leaved forest composing mainly of spruce, fir and oak with an understory of Acer, Lindera, Rhododendron, Litsea and other trees predominate. The forest of Eastern Amdo is patchy and mainly consist of junipers (Sabina). Tree species such as Picea crassifolia and P. asperata as well as Betula grow below an elevation of 3,500 metres in the Amnye Machen Range (Schaller 1998).
The forests of Southeast Amdo are known not only for their variety but also for their tremendous timber storage. For example, there are 200-year-old spruce forests in the valleys of Tramo (Ch:Bomi) county. The average diameter of the trees is 92 cm with a height of 57 metres; maximum storage per hectare is 2,000-2,500 cubic metres, and the average growth rate per year is 10-12 cubic metres per hectare
A Medical Fountainhead
According to Dr. Tenzin Choedak, senior personal physician to His Holiness the Dalai Lama, there are over 2,000 medicinal plants in Tibet. These plants have an immense potential to cure various chronic and common ailments such as asthma, hepatitis, diabetes, anaemia, tuberculosis, malaria, cancer and many other deadly diseases. For example, Taxus wallichiana, a tree found in the forests of Tibet, is the source of the allopathic drug taxol Ñ today regarded as one of the most effective remedies for certain kinds of cancer.
Examples of common medicinal plants growing on the Tibetan Plateau which are widely used in allopathic, homeopathic, Tibetan, and Chinese pharmacy includes Gastroda elata, Angelica sinensis, Coptis tectoides, Picrorhiza scrophulariiflora, Rheum officinalis, Magnolia officinalis, Terminalia chebula and Liolyophora phalloides.
The angong-niu-huang pill, a traditional Chinese medicine prescribed to relieve critical cases, is made from the grass stones formed in the gall bladder of yaks. Musk has very high medicinal value Ñ being an essential component of some traditional Chinese drugs, like liushen (six-gold) pills and musk ointment Ñ and is also a fundamental ingredient in perfumery world-wide
Since many diverse flora and fauna thrive in the forest regions of Tibet, deforestation leads to the loss of biodiversity. Tibet's total forest cover declined from 25.2 million hectares in 1950 to 13.57 million hectares in 1985 alone, which means 46 per cent destruction. According to Chinese official statistics from 1950 to 1985 Tibetan timber worth US$54 billion was felled and sold in the international timber market by China.
Felling trees, for instance, threatens to not only wipe out a number of species but is also shown to upset the complex ecological balances which regulate the amount of rain and heat a given region receives to cause soil erosion, landslides, silting, floods, drought and other perils. Because of its immense geographical extent and height, Tibet considerably influences global weather patterns by affecting the flow of jet streams over its plateau. As a huge land surface, the plateau affects the path of jet streams as an enormous iceberg would dramatically change the navigational routes of ships in oceans.Top of page
Loss of forest and grassland cover on the plateau will affect jet stream patterns, which will in turn influence the Pacific typhoons and also cause the El Nino effect. Taken together this controls the weather patterns across Europe, the USA, Mexico, Peru, India, China and other adjoining areas and will affect their ecology and economies. ( Tibet Environmental Watch (TEW) , 2001)
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