Tibet is a land of scant rainfall and a short growing season, and the only extensive agricultural region is the Yarlung Zangbo valley, where barley, wheat, potatoes, millet, and turnips are grown. In this valley as well are nearly all the large cities, including Lhasa, Xigazê (Shigatse), and Gyangzê (Gyangtse). Most other areas of Tibet are suited only for grazing; yaks, which can withstand the intense cold, are the principal domestic animals, and there are also large herds of goats and sheep. Much of the population traditionally was engaged in a pastoral life, but the advances made by irrigation and the growing of forage crops combined with Chinese attempts to spur economic development and relocate Tibetans into new housing developments have reduced nomadism and also increased the urban population. In addition to vast salt reserves, Tibet has large deposits of gold, copper, and radioactive ores.
Traditionally, goods for trade, particularly foreign trade, were carried by pack trains (yaks, mules, and horses) across the windswept plateau and over difficult mountain passes. In exchange for hides, wool, and salt there were imports of tea and silk from China and of manufactured goods from India. Motor roads now connect Lhasa with Qamdo (Chamdo) in E Tibet and with Xigazê and Gyangzê in the Yarlung Zangbo area and link Gar (Gartok) in W Tibet to the northern regions. A major highway runs from Tibet to Chengdu, in Sichuan prov., providing a link to the great Chinese cities in the east; Tibet is also connected by highway with Xinjiang and Qinghai in W China. A rail link to Qinghai prov. was opened in 2006.