This article is about forests as a massing of trees. For other uses of the word, see Forest (disambiguation).
A dense growth of softwoods (a forest) in the Sierra Nevada Range of Northern California

A forest is an area with a high density of trees (or, historically, an area set aside for hunting). Forests can be found in all regions capable of sustaining tree growth, at altitudes up to the tree-line, except where rainfall is too low, or natural fire frequency too high. Forests generally contain a large number of different tree species growing to different heights, combined with an understory, which makes efficient use of sunlight. A forest in its natural form is home to many animal and plant species, and biomass per unit area is high compared to most other biomes.

In ecological terms, a forest may be differentiated from a woodland: a forest is considered to have a more or less closed canopy, where the branches and foliage of trees meet or interlock; a woodland is considered to have an open canopy, where some sunlight penetrates between the trees (see also: savanna).

Numerous types of forests exist. Among the ecological types are:

The science of studying and managing forests, with a goal of sustainable extraction, is called forestry. Ecologists study forests.

See also

da:Skov de:Wald es:Bosque eo:Arbaro [[fr:For�t]] it:Foresta la:Silva nah:Cuauhtla nl:Bos ja:森林 pl:Las (biologia)