A savanna is a mixed woodland-grassland biome and ecosystem. It is characterized by trees that are spaced widely enough to prevent the formation of a closed canopy. This open structure allows sufficient light to reach the ground, supporting an unbroken layer of herbaceous vegetation, which consists primarily of grasses.
There are four distinct forms of savanna based on the distribution of vegetation: savanna woodland, where trees and shrubs form a light canopy; tree savanna, featuring scattered trees and shrubs; shrub savanna, defined by distributed shrubs; and grass savanna, where trees and shrubs are mostly nonexistent.