The tropical grasslands have an estimated Net primary Productivity of 900g/m2/year. This is considerably less than the rainforest, partly because of the smaller number of trees, species and layers and partly because, although grasslands have the potential to return organic matter back to the [?], the rate of decomposition is reduced by the winter [?] leaving considerable amounts left stored in the litter.

The Savanna includes a series of transitions between the equatorial rainforest and the hot [?]. At one extreme, the 'park' savanna is mainly [?] with areas of grasses; at the other the scrub savanna is vegetated by only scattered tufts of grass. The trees are [?] and, like those in the UK, lose their leaves to reduce [?], but, unlike the UK, this is due to the winter drought rather than the cold. Trees are xerophytic, or drought [?]. Even when leaves do appear, they are small, waxy and sometimes thorn-like. Roots are long and extend to tap any [?] water. Trunks are gnarled and the bark is usually thick to reduce water loss.

The baobab tree (also known as the 'upside down tree') has a trunk of up to 10m in diameter in which it stores [?]. Its root-like branches hold only a minimum number of tiny leaves in order to restrict transpiration. Some baobabs are estimated to be several thousand years old and, like other savanna trees, are pyrophytic, i.e. their trunks are resistant to the many local [?]. Acacias, with their crowns flattened by the [?] winds, provide welcome but limited shade. Savanna trees reach 6-12 metres high. Many have Y-shaped, branching trunks - ideal for the leopard to rest in after its meal! The number of trees increases near to [?] and waterholes.

Grasses grow in tufts and tend to have inward curving blades and silvery spikes. After the onset of the [?] rains, they grow very quickly to over 3m in height: elephant grass reaches 5m. As the sun dries up the vegetation, it becomes [?] in colour. By early winter the straw-like grass has died down, leaving [?] dormant on the surface until the following season's rain. By the end of winter, only the [?] remain and the surface is exposed to wind and rain.

Over 40 different species of large [?] graze on the grasslands, including wildebeest, zebra and antelopes. It is also home to carnivores - both predators, such as lions, and scavengers, such as [?]. Termites and microbes are the major decomposers. Fire is possibly the major determinant of the savanna biome - either caused deliberately by farmers or resulting from [?] associated with summer electrical storms.

It is in the fringes of the savannas, those bordering the hot deserts, which are at greatest risk of [?]. As more trees are removed for [?] and overgrazing reduces the productivity of grasslands, the heavy rain forms gullies and wind blows away the surface soil. Where the savanna is not farmed, there are usually more trees, suggesting that [?] may not be the natural climatic climax vegetation.