Tropical Savannas (alternate sp. savannah) are a grassland biome, dotted with trees, generally located at tropical latitudes. It is much drier than most tropical forest. Rainfall on savanna is between 50 and 150 centimeters (20 to 60 inches) a year, and can be very seasonal, with the entire year's rainfall sometimes occurring within a couple of weeks. Although the term "savanna" is believed to have originally come from an Amerindian word describing "land which is without trees but with much grass either tall or short" (Oviedo y Valdes, 1535), by the late 1800s it was used to mean land with both grass and trees. It now refers to land with grass and either scattered trees, or an open canopy of trees. Although rainfall is generally seasonal, rivers are found in many savanna regions and often cause seasonal floods. Much of the plant life on savannas is adapted to this seasonal aridness, either having long tap roots to reach water tables, or bulbs to store water.
Native Americans created subtropical savannas by periodic burning in some areas of the US southeastern coast where fire-resistant longleaf pine was the dominant species. Most other tree species were killed, resulting in widely spaced longleaf pines with grassland between the trees. Savannah, Georgia, is named after such an area. Farther north, as in between Seneca Lake and Cayuga Lake in the Finger Lakes of New York, such burning killed all the trees and created prairie instead.
See also: Temperate Savannas