Savannas are characterized by a continuous cover of perennial grasses, often 3 to 6 feet tall at maturity. Distinction is made between tree or woodland savanna, park savanna, shrub savanna and grass savanna. A tropical wet and dry climate predominates in areas covered by savanna growth. For at least five months of the year, during the dry season, less than 4 inches a month are received. The dry season is associated with the low sun period.
Soils vary according to bedrock and edaphic conditions.
In general, however, laterization is the dominant soil-forming process and low fertility oxisols can be expected. East African savannas are typically, perhaps stereotypically, acacia savannas. Many survive in the famous game parks of Kenya and Tanzania, and also those of Zimbabwe, Botswana, South Africa, and Namibia. The famous Serengeti Plains in Tanzania are a grass savanna developed on droughty but nutrient-rich volcanic sands. The llanos of the Orinoco basin of Venezuela and Columbia are grass savannas maintained by the annual flooding of the Orinoco River and long periods of standing water that inhibit the growth of most trees.