INTRODUCTION AND BACKGROUND

Many developing countries' problems are compounded by severe environmental damage, including deforestation, soil erosion and biodiversity loss. Deforestation continues at an alarmingly high rate – about 13 million hectares per year – although the net loss in forest area in the period 2000–2005 is estimated at 7.3 million hectares per year. Seventy-four percent of rangelands and 61% of rain-fed croplands in Africa's drier regions are damaged by moderate to very severe desertification. In some African countries, deforestation rates exceed planting rates by 3,000%. The area of the globe affected by water erosion is roughly 11 million square kilometres and the area affected by wind erosion is around 5.5 million square kilometres. Combined, this equates to an eroded area some 241 times the size of Tasmania. With species extinctions running at about 1,000 times the ‘background’ rate, some biologists contend that we are in the middle of the earth's sixth great extinction.

For many years in Sahelian countries, conventional Western forestry methods were applied to solving desertification and deforestation problems, and exotic tree species were typically favoured over indigenous species. Large and small tree-planting projects were commissioned to curtail the southward movement of the Sahara Desert, but few made any lasting impression. Little thought was given to the appropriateness of this approach. Existing, indigenous vegetation was generally dismissed as ‘useless bush’. In the name of aforestation, many projects even cleared existing woody vegetation in order to make way for exotic species.