Deserts are expanding throughout the world, hillsides are being washed away, reservoirs are silting up, and the entire Biosphere is becoming polluted. Directly or indirectly, one of the main causes of many of these misfortunes is the destruction of woods and forests.

As most educated people are now aware, particular concern is being directed, these days, to the destruction of the world's tropical rain-forests—most of which will, in all probability, disappear before the end of the present century—and to desert encroachment.

Unfortunately, these two vast environmental problems are not unrelated. It is only a short step from 'green jungle' to 'red desert', as some of the inhabitants of Brazil are learning to their cost. Whether or not the United Nations Environment Programme (UNEP), the International Union for Conservation of Nature and Natural Resources (IUCN), and other international agencies, are successful in persuading the governments of the countries concerned to initiate programmes to preserve some of their forests and to combat desertification, the problem will still remain of dissuading the local people from
indulging in 'slash and burn' cultivation or serious overgrazing (according to the region and other circumstances involved).