ABSTRACT
On the northern fringe of Monsoon Asia is a wide belt of desert and semi-desert reaching from the western end of the Tarim Basin for 2,500 miles through the Taklamakan and the Gobi to the western border of Manchuria. There is also desert in the Indus valley of West Pakistan and neighbouring parts of India. In the country bordering the deserts rainfall is low and the natural vegetation is grass. In the grassland and desert of the Tarim Basin there are oases with natural woodland wherever streams from nearby mountains bring additional water. In the Himalayas above I3 ,ooo ft. and in Tibet there is mountain grassland and mountain tundra vegetation. The plant cover of these northern areas, together with the local relief, was an important element in historical geography. The oases determined the alignment of the land routes from China to the west, the mountains and higher plateaux were barriers to movements of people, and the grassland early became the home of nomadic people whose periodic invasions of the richer agricultural lands to the south had profound effects in India and China. Over the remaining, vastly larger part of Monsoon Asia the natural vegetation is forest. In crowded areas, especially China, India, Pakistan and Java, the forest has been completely cleared from enormous areas to make room for cultivation. Other countries, notably Malaya, Sumatra, Borneo and Burma, are still well wooded.
