![Picture](/uploads/1/1/4/2/11423524/6087260.jpg)
Tropical graslands are sctatered with individual trees. Tropical grasslands are also known as savannas. Savannas of one sort or another cover almost half the surface of Africa. The soil of the savanna is porous, with rapid drainage of water. Savanna has both a dry and a rainy season. Seasonal fires play a vital role in the savanna's biodiversity. Most savannas receive an average annual rainfall of 30 to 40 inches. However, certain savannas can receive as little as 10 inches. The soil of the savanna is porous, with rapid drainage of water. It has only a thin layer of humus which provides vegitation.