About one fifth of the Earth's land once had a cover of grass. Any more, the land would become a forest. Any less, the land would become a desert.
Grasslands are often the transition from desert to forest.
Near the forests where rainfall is abundant, trees grow intermixed with tall grasses. Trees are limited to river and stream basins. What is most striking about the grassland is how open and continuous the area is. It seems as though there is an endless ocean of grass. As the grasslands stretch away from the forests, the rain decreases and soil conditions change.