A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending on various cultural definitions, what is considered a forest may vary significantly in size and have different classifications according to how and what of the forest is composed. These plant communities cover approximately 9.4 percent of the Earth's surface (or 30 percent of total land area), though they once covered much more (about 50 percent of total land area), in many different regions and function as habitats for organisms, hydrologic flow modulators, and soil conservers, constituting one of the most important aspects of the biosphere. Although forests are classified primarily by trees, the concept of a forest ecosystem includes additional species (such as smaller plants, fungi, bacteria, and animals) as well as physical and chemical processes such as energy flow and nutrient cycling.

A typical forest is composed of the overstory (canopy or upper tree layer) and the understory. The understory is further subdivided into the shrub layer, herb layer, and also the moss layer and soil microbes. In some complex forests, there is also a well-defined lower tree layer. Forests are central to all human life because they provide a diverse range of resources: they store carbon, aid in regulating the planetary climate, purify water and mitigate natural hazards such as floods. Forests also contain roughly 90 percent of the world's terrestrial biodiversity.

Noun

forest (plural forests)

1. A dense collection of trees covering a relatively large area. Larger than woods.
2. Any dense collection or amount.

   Forest of criticism.

3. A defined area of land formerly set aside in England as a royal hunting ground.
4. (graph theory) a disjoint union of trees

• forestal
• forest-bill
• forested
• forester
• forestial

• forestlike
• forestry
• can't see the forest for the trees
• rainforest

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• Tropenbos International
  tropenbos.nl
  Tropical forest research for nature conservation and sustainable use of rain forests in Cameroon, Colombia, Guyana, Ghana, Indonesia, Ivory Coast, Vietnam.
• BIOTA-AFRICA
  biota-africa.de
  A German-supported (mega)transect study of the Biodiversity of West Africa (Ivory Coast, Burkina Faso, Benin), East Africa (Kenya, Tanzania and Uganda), and Southern Africa (Namibia and South Africa).
• Ecological restoration of Scottish Wildwood
  carrifran.org.uk
  Carrifran Wildwood Project-begun on January 1st, 2000- is recreating an ancient woodland in 1600 acres of Southern Scottish upland valley