It has only a thin layer of humus (the organic portion of the soil created by partial decomposition of plant or animal matter), which provides vegetation with nutrients. Savannas are sometimes classified as forests. The predominant vegetation consists of grasses and forbs (small broad-leaved plants that grow with grasses). read more
Vegetation. Grassland vegetation can vary in height from very short, as in chalk grassland, to quite tall, as in the case of North American tallgrass prairie, South American grasslands and African savanna. read more
Grasslands are characterized as lands dominated by grasses rather than large shrubs or trees. In the Miocene and Pliocene Epochs, which spanned a period of about 25 million years, mountains rose in western North America and created a continental climate favorable to grasslands. read more