Rainfall, primarily. Native trees need more water than Great Plains provide; once planted and started, some trees can live, but Native Americans seldom did that. Giant grazing bison discourage trees. read more
Prairies are large areas of mostly treeless grassland found all over the world including North America, South America, Europe, Asia and Africa. This biome is characterized by moderate temperatures, moderate rainfall and vast stretches of flat land. read more
Prairie in North America is usually split into three groups: wet, mesic, and dry. They are generally characterized by tallgrass prairie, mixed, or shortgrass prairie, depending on the quality of soil and rainfall. Wet. In wet prairies, the soil is usually very moist, including during most of the growing season, because of poor water drainage. read more
Prairies are large areas of mostly treeless grassland found all over the world including North America, South America, Europe, Asia and Africa. This biome is characterized by moderate temperatures, moderate rainfall and vast stretches of flat land. Tall grasses prevent erosion, so grassland prairies are ideal for agricultural activities. read more