Gyirong Valley

Gyirong Valley is at the southern foot of the central Himalayas. It stretches from north to south for over 100 kilometers, beginning at the Gyirong County and going all the way down to Gyirong Port, the China-Nepal border. With ridgelines on its both sides as its boundaries, the valley is 300 to 2000 meters in width and covers an area of about 2500 square kilometers. Because connections between Gyirong and Lhasa are hindered by Mount Marrah (altitude: 5770m) at the north of the valley, Gyirong Valley has become a relatively closed area where few people live and visit in history.

The altitude of Gyirong Valley is 1700 meters in the south before it is raised to about 7000 meters in the north. The difference in altitude in the valley plus the warm wet airflows coming from the Indian Ocean hitting the south slope of the Himalayas form a unique vertical ecosystem combination: in the south there’re ditches and rivers, in the central area there’re forests and in the north there’re snow mountains and glaciers. In just about 100 kilometers there’re all together six major ecosystems, forming a unique vertical landscape system.

Gyirong County, with an altitude of about 4200 meters, is located at Zongga Town in the north of the valley. Gyirong Town, the second biggest town in the county, is at the south of the valley. It is 75 kilometers from Gyirong County and 24 kilometers north of Gyirong Port (the China-Nepal border).

The Himalayas sprawls from east to west, blocking the south-coming warm wet airflow from the Indian Ocean and making the climates of the north and south slopes very different. The north of Gyirong is a cold semi-arid plateau-valley monsoon climatic region with an annual average temperature of 2℃, the warmest month temperature of 10-18℃, the coldest month temperature of -10℃ and an annual precipitation of around 300-600 millimeters. It has a semi-arid continental climate. On the other hand, the south of Gyirong has a subtropical mountain region monsoon climate with an annual temperature of 10-13℃, the warmest month temperature of over 18℃, an annual precipitation of around 1000 millimeters and an annual number of frost-free days at above 200. Its winters are short and rainy and it doesn’t have four distinct seasons—it’s like spring all year round with flowers blossoming and it’s always warm and wet.

Gyirong Valley is an important part of the Himalayas National Natural Reserve and is the biggest area with the most beautiful ecological environment and the biggest variety of ecological species in the reserve. Key protective plants and animals in the Himalayas Natural Reserve are widely distributed in the area and some species only inhabit in this area, which makes the area one of the most important regions in the reserve. Therefore, Gyirong Valley is also called as “the back garden of the Himalayas”. Forests of picea smithiana, taxus wallichiana and pinus palustris grow in the area and there’re also many valuable and rare animals here, such as assamese macaque, himalayan tahr, semnpithecus entellus, moschus leucogaster, lophura leucomelana, himalayan goral, selenarctos thibetanus and blood pheasant.

Geologists have found palaeotherium orictocoenosis mainly features as Gyirong three-toed horse fossils in the western Gyirong County. The orictocoenosis includes over ten mammals like Gyirong three-toed horse, Tibetan chilotherium and Gyirong Ochotona. This relic implies that in pliocene epoch (30 million years before) the altitude of West Himalayas was between 500 to 1000 meters and Mount Everest was around 3000 meters in altitude. Climate was warm and wet and the places had natural landscapes like forests and grasslands. Since then, the Gyirong basin has risen by about 2500 to 3000 meters.