44 SOCIAL SC1ENIIST 4 million ha. in Asia1. Contrary to this, in the advanced countries, forests occupy a considerably larger proportion of their geographical area. It is reported that in Northern Europe, 48 per cent of the geographical area is covered by forests; in Eastern Europe and USSR it is 45 per cent. The average forest area for the whole of Europe is 41.35 per cent. The forest area in Northern America is 33.3 per cent, in Central and South America it is 38.9 per cent. In West Asia it is only 3.4 per cent. In 1961, the total forest area in Asia was 19 per cent, Africa 25 per cent and in the Pacific area only 11 per cent of the total geographical area.2 Besides the paucity of fuel-wood, the fast disappearance of the forests has resulted in the disturbance of the ecological system. According to an UN estimate, some 10 per cent of the world's population lives in the mountainous areas. But the ill-effects of deforestation in terms of wind and soil erosion, silting, flooding and drought also affect another 40 per cent of the population which lives in the adjacent lowlands. In India, 50 per cent of the total land area is seriously affected by water and wind erosion. The displacement of the fertile top soil is estimated to be around 6,000 million tonnes a year. In Pakistan, erosion affects 76 per cent of the total land area.3 The deforestation has also resulted in serious landslides and in the drying up of fresh water springs in the Himalayan region creating a shortage of drinking water. Most of the streams have become seasonal. Soil erosion causes the silting of rivers and water reservoirs. The river beds of the Napalese Terai are rising at the rate 15 to 30 cm a year.4 In India, the rate of erosion of the Sutlej is 150 acre feet per 100 square miles. In the case of the Beas and the Jamuna it is 250 and 400 acre feet respectively per 100 square miles. In the case of the Kosi, it has risen to 500 acre feet per 100 square miles. As against this, in the U S A, in the Columbia river it is one, in the Mississippi six, in the Tennessee 12, in the Colorado 36 and in the Rio Grande 61 acre feet per 100 square miles of watered area. This heavy rate of silt flowing into the Indian rivers has drastically reduced the life span of river dams. The silting rate of the dams constructed during the Third and Fourth Plan periods has been 213 per cent higher than the original estimate.5 The Mangia reservoir, for example, was built to last for 100 years or more. But the sediment measurement after a few years of operation revealed that after 50-75 years the reservoir would become unusable.6 In terms of rupees, the annual loss caused by the disturbance of the Himalayan eco-system in the Indian subcontinent is about Rs. 1200 crores, through floods, crop damage and sedimentation. Rs. 10,000 crores worth of land (about seven million hectares) has already been lost. During the 1951-1969 period, the river valley projects, extension of agriculture, townships, industries, construction of roads, canals, power transmission lines, etc. have claimed another 1,836,250 hectares of existing productive forest land. 7