Savanna woodlands, are characterized by a ground covered by grasses, with some trees interspersed. Savannas are open canopied habitats, intermediate between grasslands and forests. In general, as available moisture increases in a terrestrial system, so too does the density and complexity of the vegetation. Little or no rain yields desert. A lot of rain yields rainforest. Intermediate prevailing rainfall amounts result in the formation of grasslands, savannahs, and other forests types.
Links to further information on Savanna Woodland
http://www.nri.org/tsetse/Plan/savann.html more examples of African Savanna Woodlands and the tsetse fly
http://www.nmwild.org/wild/fl_woodland.htm Savanna Woodland in New Mexico, US
http://www.fws.gov/carolinasandhills/longleaf.html Longleaf Pine/ Wiregrass Ecosystem Eastern US
http://www.inhf.org/oaksavannas.htm Iowas Oak Savanna
http://en.wikipedia.org/wiki/Savanna Wikepedia Page on Savanna
Longleaf Pine Savanna: Sandhills area in southern North Carolina
Longleaf Pine savanna of the S.E. US as seen in Scotland County, North Carolina. Note the fairly open aspect of the forest. Sunlight is able to reach the ground layer of grasses, and pine straw through an open canopy.
This low-angle photo shows tufts of grasses in the foreground, the trunks of Longleaf Pine trees, and the open canopy in the background.
Longleaf Pine trees owe their name to the impressively long pine needles. They impart a brush-like appearance. This is a habitat that rings with the beautiful song of Bachman's Sparrow, the chattering of groups of Brown-headed Nuthatches, and the excited calls of the endangered Red-cockaded Woodpecker.