1.1. Geographic position of the country
1.2. Socio-economic information
1.3. Ecological information
Sudan, the largest country in Africa, lies entirely within tropical zone. Its area is approximately 2.5 million km² surrounded by the Red sea from the east and 8 countries on the other sides. The population was estimated as 28 million growing at a rate of nearly 3% per annum. Population of the urban areas is about 34% with 14% in the capital Khartoum. Nomads constitute 14% of the population.
Population density is 11.2 inhabitant/km² with an annual rate of change (1995-2000) of 2.2% according to FAO (1999). Fig.2 shows the density distribution patterns within the country. Annual growth of GDP (1990-1995) is 6.8%.
Fig. 1: Administrative map of Sudan
Fig. 2: Population density of Sudan (inhab./km²)
The physiography of the country is simple, with climatic and vegetation distribution in belts extending across the country from east to west.
Sandy soils constitute about 60% of the country distributed in the northern and North-East and the western parts. The heavy clay soil of the central and eastern part of the country constitutes about 30%. The remaining 10% are red soils, characteristics of the southern part of the country. Annual rainfall varies between O in the north and 1500 mm in the south.
Variation in annual rainfall and soil type has produced various vegetation types from desert in the northern zone to closed high forest in the most southern part of the country. The country is consequently divided into seven vegetation zones on the basis of rainfall and soil. Starting from the north to the south, these zones are: desert (zone 1), semi-desert (zone 2) rainfall woodland savannah on clay soil (zone 3), low rainfall woodland savannah on sand (zone 4), high rainfall woodland savannah (zone 5), special forests (zone 6) and the montane forests (zone 7).
Topography effect is confined to small areas that are the hilly, mountains and the river Nile tributaries (Andrews, 1948). The central part of the country with rainfall confined to rainy season (3-5 month) is dominated by deciduous drought tolerant tree species. Soil effect is demonstrated by Acacia senegal that thrives on annual rainfall of 400 mm in sand while it requires 600 mm in the heavy clay soils. The vegetation zones of the forests have been further delineated into seed zones by the National Tree Seed Centre (NTSC) according to ecological conditions as described in the NTSC publication n°6.
Approximately half the area of the country (50.5%) is desert and semi-desert. If the term dryland is to denote areas of evapotranspiration in excess of total rainfall, then the whole of Sudan is a dryland with the exception of riverine areas, the most southern parts of the country and some of the mountains.
Forests and woodland range from Savannah woodland, in areas of annual rainfall of about 400 mm to tropical high rainfall forest which are mainly in the southern mountains. The arid parts carry only scanty vegetation and woody species are confined to few acacias in the seasonally flooded areas. The low rainfall savannah houses the main species currently utilized like Acacia senegal, the gum arabic producing tree and Acacia nilotica of the riverine forests. Other important species are Anogeissus leiocarpus, Terminalia spp., Combretum spp, Bowswelia spp. and some palms mainly Hyphaene sp. and Borassus spp. The high rainfall savannah areas contain the most valuable forests of the country that have largest potential of producing sawn timber.
