Although definitions vary somewhat, savannas typically refer to landscapes dominated by grasses and widely spaced trees. This can mean the iconic tropical savannas of eastern and southern Africa, or temperate-zone open woodlands of pine or oak. Wherever their location, savanna plants exhibit unique adaptations.
Many of the world's savannas exist partly or wholly because of fire, whether sparked by lightning or intentionally set by human beings. In the Intermountain West of North America, ponderosa pine forms savannas and open woodlands between steppe and higher conifer forests, partially maintained by wildfire. The old, thick-barked pines withstands many blazes, while seedlings readily colonize fresh-burnt territory.
Many savanna plants deal with heavy grazing pressure, as in certain savannas of the world, tropical versions in Africa and India for example, a great diversity of grazing and browsing mammals exist. Savanna grasses often afford to be munched to the soil, resprouting leaves from their subterranean growing points.
Plants in both tropical and temperate savannas often contend with moisture limitations. Many tropical savannas experience annual dry seasons where rainfall is scant or nonexistent. In Africa, the baobab, a common tree of savannas and open woodlands, only leafs out during the rainy season. Many grasses reserve energy underground during the dry season, only greening when the rains come.
- U.S. Forest Service: Silvics of N. America: Ponderosa Pine; R.M. Burns, B.H. Honkala; 1990
- "A Sierra Club Naturalist's Guide to the Pacific Northwest"; S. Whitney; 1989
- Wheeling Jesuit University: Tropical Savannah - Plants
- Photo Credit Comstock/Comstock/Getty Images Fire 11 image by Valeriy Kirsanov from Fotolia.com kenya image by TEMISTOCLE LUCARELLI from Fotolia.com Baobab before the sunset image by Elzbieta Sekowska from Fotolia.com
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