Forest and Woodland’s Ecosystem in the World

Forest ecosystem covers 53 million square kilometers or 40 percent of the Earth’s land surface. They exist in an extraordinary variety of forms according to the climate, the soil, the lie of the land and the ways they have been used and modified by people. In some, trees are naturally spaced out forming open woodland or savannah; in others the trees crowd densely to create a closed canopy over the ground. Closed forest now cover approximately 29 million square kilometers, four fifth of their extent 300 years ago. Most of the cultivated and inhabited land of today was once clothed in forest.

The world’s largest stock of trees lies in the great northern forest belt of Eurasia and North America, the taiga. The taiga, or boreal forest, is a relatively simple, species-poor ecosystem, dominated by conifers that can survive long, cold winters.

The temperate forests to the south of the taiga contain a greater variety of plants and animals, in various associations, including coniferous, broadleaf and mixed forests and the mixed shrub lands that are characteristic of Mediterranean regions. Much of the area that they formerly covered has long been cleared for human occupation, and is now devoted to settlements, crops and pastures, with only patches of woodland remaining, and even fever areas of old-growth forest. Temperate forests also grow in areas that have similar climates in the southern hemisphere.

Tropical forest ecosystems, particularly the rain forests, are the most species rich of all. Forming an evergreen girdle on the land around the Equator, they support not only an immense variety of trees and other plants, but also abundant animal life.

In less well-watered areas of the tropics there are dry forests, less dense and luxurious, but characterized by thicker undergrowth. The savannahs, where scattered trees and shrubs are interspersed with patches of grass and herbaceous plants, are home to large herds of grazing mammals and their predators.