|Patryck Vaucoulon/Still Pictures|
Forests and woodlands have played a critical role in the survival of human populations. They have been direct providers of shelter and food for people and their livestock, and of water, medicinal plants, building materials and fuel. But forests and woodlands also regulate our environment indirectly by slowing soil erosion, controlling run-off of rainwater and storing it, and regulating its release into our rivers and lakes. Globally, they help to regulate the climate and protect coastlines. Furthermore, forests and woodlands sustain many of our cultural, spiritual and religious values as well as playing an important role in the socio-economic development of industrial countries and being a vital resource for the socio-economic stability of developing ones. Loss of forests and woodlands therefore means loss of a vital resource and disruption of the socioeconomic activities they support. The emphasis in recent years on sustainable development has meant that the use of forests and woodlands has come under greater scrutiny in order to preserve a healthy resource base and sustain social and economic benefits.
Figure 2d.1: Map of African forest cover and types
Tracking long term trends in forest cover involves the compilation and analysis of large quantities of data that are not always consistent or comparable and the task is further complicated by different definitions of what constitutes 'forest' (IPCC 2000, UNEP 2001, Matthews, Payne, Rohweder & Murray 2001). Forests may be defined in terms of administrative categories, land use or land cover (IPCC 2000). The United Nations Food and Agriculture Organization (FAO), in collaboration with UNEP and the UN Economic Commission for Europe (UNECE) produces an assessment of the world's forests every 10 years. These are widely cited, and much of the information presented below is taken from the 2000 FAO Forest Resources Assessment. For the FAO report, the term 'forest' means land with a tree canopy cover of more than 10 per cent and area of more than 0.5 hectares, and a minimum tree height of 5 m. A canopy cover threshold of 10 per cent can include land that might be considered tundra, wooded grassland, savanna or scrubland (Matthews 2001). The discussion in this section will, therefore, include forests, woodlands and savannas. It should be noted that natural events and human activities can affect open and closed canopy forests in different ways.Forests cover approximately 30 per cent of the world's surface, with tropical and subtropical forests (and woodlands) comprising 56 per cent, temperate and boreal forests accounting for 44 per cent. These are all natural forests with the exception of 5 per cent of forest plantations, (FAO 2001a). It has been estimated that, since pre-agricultural times, global forest cover has been reduced by at least 20 per cent, and perhaps by as much as 50 per cent (UNDP, UNEP, World Bank & WRI 2000).
The total forest cover in Africa was estimated to be just under 650 million hectares in 2000, equivalent to 17 per cent of the global forest cover, and approximately 22 per cent of Africa's land area (FAO 2001a). Africa has 14 different types of forest, in temperate and tropical climates, as shown in Figure 2d.1, although the extent of forest cover varies between sub-regions. Forests make up approximately 45 per cent of the land area of Central Africa, constituting 37 per cent of Africa's total forest cover. In contrast, only 8 per cent of the land area of countries in Northern Africa have forest cover and most of this is in Sudan (FAO 2001a).