The Grassland biome is dominated by grasses of a variety of species,
all having adapted to the summer drought common to their semiarid habitat.
The broad expanse of the grasslands is occasionally broken by stands of trees.
The midlatitude grasslands of have been exploited more than any other biome by humans.
The grasslands, especially the tall grass prairies are the world's most productive agricultural areas.
The famous corn belt of the United States was created on top of the rich brown mollisol soils that developed beneath the surface.
The Prairies
Tall Grass Prairie
Steppe Grassland
The Forest Biome
The forest biome consists of close growing trees with leaf canopies that generally overlap.
Much sunlight can be prevented from reaching the forest floor if tree limbs and foliage tightly intermingle.
The lack of sunlight inhibits the development of undergrowth, creating an open forest structure.
If the canopy is open, sunlight can reach the forest floor and promote the development of undergrowth resulting in a closed forest structure.
Forests require ample amounts of annual precipitation to support their growth.
The shaded conditions of the closed forest keep soils relatively moist.
The Tropical Rain Forest
Prairies are found on the humid side of the grassland biome and are often referred to
as the tall-grass prairie. A favorable annual moisture balance supports a dense ground
cover of tall grasses. Grasses range in height between .6 to 1.2 meters (2 to 4 ft.),
with some as tall as 8 feet or more on the eastern margin of the prairies in the United States.
Trees and shrubs are generally limited to moist sites along stream channels or hill slopes facing away from the sun.
The nutrient - rich soil beneath the grasslands drew farmers to these regions.
Now, most natural tall-grass prairie has been replaced by agriculture.
Extensive grasslands also occur in Argentina and the Ukraine.
The native grasslands of the world support a diversity of animal life.
In North America, large grazers like the bison roamed the grasslands until hunted to near extinction by settlers moving west.
On the drier side of the grassland biome lies the steppe grasslands.
Vegetation must cope with the summer soil moisture deficit common to the steppe climate in which this formation class is found.
Here, tall grass prairie gives way to grasses smaller than a half meter (2 ft).
The Tropical Rain forest contains trees standing 30 to 55 meters in height, creating a continuous canopy of foliage.
The enclosed canopy shades the forest floor, creating an open forest formation.