DefinePK

Abstract

ABSTRACT The forests are, were, and will remain a major land use all over the world. They are a vast and vital part of the earth's ecosystem and constitute its natural climax vegetation. They are essential for climatic stability, prevention of global warming and conservation of biological diversity. Originally, about 10,000 years ago, two third of earth's surface was covered with forests. Presently, only half of this forest area is left. World-wide, the biggest threat to forest resources has been clearance of forests for agriculture. This has also resulted in aridity in many countries. Although, some salinity generally occurs in arid and semi-arid regions of the country because of low precipitation, high temperatures and high rate of evaporation in them, still, most of the soil degradation, including salinity and waterlogging have occurred in these regions due to removal of natural vegetation of dry tropical thorn forests and disturbance of natural ecosystem and drainage in the first instance which was subsequently extended by faulty irrigation practices for production of food and fiber to meet the needs of increasing population. In the latter case, the seepage of irrigation water from unlined water courses has aggravated the problem to an enormous and critical extent. Unfortunately, role of forests in this regards is little understood and only mechanical means have been used to reclaim salt affected and waterlogged areas at a great expense by the government agencies such as WAPDA and accepted by the public at large.