Approximately 30 percent of the earth's surface is covered in forests, according to Elizabeth Mygatt, author of the article, "World's Forests Continue to Shrink." Mygatt goes on to further explain the crucial role that forests play in maintaining a healthy planet, such as controlling the water cycle and stabilizing soils, assisting in leveling the climate by saturating and storing carbon dioxide, providing a habitat for wildlife and supplying wood, food and medicines. Across the world there are several different types of forest ecosystems. The textbook definition of ecosystem, as stated in "Elemental Geosystems," is, "a self-regulating association of living plants, animals and their non-living physical and chemical environment."
Days usually last 12 hours, temperatures averaging around 77 degrees F, surplus of rain and high insolation (sunlight) are all attributes of a tropical rain forest year-round. Tropical rain forests cover the Amazon region, as well as equatorial regions in Africa, Southeast Asia, the east coast of Central America and elsewhere along the equator. These areas are characterized by broadleaf evergreen trees, vines, tree ferns and palms.
Located on the edges of rain forests are the tropical seasonal forests that receive dwindling and irregular rainfall. These areas are characterized by broadleaf evergreen trees, some deciduous trees and thorn trees. Deciduous trees lose their leaves during the winter.
Found in North America, Europe and Asia, temperate evergreen and deciduous forests tend to blend together at times. Needleleaf and broadleaf trees inhabit the forests. In southern and eastern areas that are fervent with evergreen pines, controlled forest fires still take place as the natural cycle of forest re-growth and enrichment. As far as weather conditions, it is a moderate climate with a cold season.
The boreal forest, also known as the needleleaf forest, covers most of the subarctic climate areas located in Canada, Alaska, Siberia, Russia and Europe. "Taiga" is a broader term used for boreal forest in order to encompass areas transitioning to arctic climate conditions. While there aren't any boreal forests in the Southern Hemisphere, there are mountain forests comprised of needleleaf trees that survive all over the world at extremely high elevations.
Savanna and woodland ecosystems have a susceptibility to fires and the ability to rejuvenate and re-grow. Prevalent in South America, Africa and Australia, savannas and woodlands are characterized by vast areas of grasslands, bush thickets and clusters of sparse trees with flattened crowns.