Forest
From Freepedia
- This article is about forests as communities of trees. For other uses of the word, see Forest (disambiguation).
A forest is an area with a high density of trees (or, historically, a wooded area set aside for hunting). These plant communities cover large areas of the globe and function as carbon dioxide sinks, animal habitats, hydrologic flow modulators, and soil conservers, constituting one of the most important aspects of our biosphere.
Forests can be found in all regions capable of sustaining tree growth, at altitudes up to the tree-line, except where natural fire frequency is too high, or where the tree growing environment has been impaired by natural processes or humans. Forests sometimes contain many tree species in a small area (e.g. tropical rain and temperate deciduous forests), but other forest types have relatively few species over large areas (e.g. taiga and arid montane coniferous forests). As a general rule, forests dominated by angiosperms are species-rich, while those dominated by gymnosperms are not so rich, although exceptions do exist (e.g., species-poor aspen and birch stands in northern latitudes). Forests are often home to many animal and plant species, and biomass per unit area is high compared to other vegetation types. Much of this biomass occurs below-ground in the root systems and as partially decomposed plant detritus. The woody component of forests contains lignin, which is relatively slow to decompose compared with other organic materials such as cellulose or carbohydrate.
Forests are differentiated from woodlands by the extent of canopy coverage: in a forest the branches and foliage of separate trees often meet or interlock, although there can be gaps of varying sizes within an area referred to as forest. A woodland has a more continuously open canopy, with trees spaced further apart, which allows more sunlight to penetrate to the ground between them (see also: savanna).
Among the major forested biomes are:
- rain forest (tropical and temperate)
- taiga
- temperate hardwood forest
- tropical dry forest
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Classification
Image:Pine tree forest02.jpg Forests can be classified in different ways and to different degrees of specificity. One such way is in terms of the biome in which they exist combined with leaf longevity of the dominant species (whether they are evergreen or deciduous).
- Boreal forests occupy the subarctic zone and are generally evergreen and needle-leaved. Temperate zones support both deciduous forests (e.g., temperate deciduous forest) and evergreen forests (e.g., temperate rainforest).
- Tropical and subtropical forests include tropical rainforest, tropical moist forest and tropical dry forest.
- Physiognomy classifies forests based on their overall physical structure or developmental stage (e.g. old growth vs. second growth).
- Forests can also be classified more specifically based on the dominant tree species present, resulting in numerous different forest types (e.g., ponderosa pine/Douglas-fir forest).
Forest management
The scientific study of forests is referred to as forest ecology, while the management of forests is often referred to as forestry, often with the goal of sustainable resource extraction. Forest ecologists concentrate on forest patterns and processes, usually with the aim of elucidating cause and effect relationships. Foresters often focus on wood extraction and silviculture, including tree regeneration and growth processes.
Forests can be damaged by logging, forest fires, acid rain, herbivores, and diseases, among other things. In the United States, most forests have historically been affected by humans to some degree, though in recent years environmental protection has helped regulate or moderate large scale or severe impacts.
See also
Image:Forest on San Juan Island.jpg
General
- Biosphere
- Ecological succession
- Forest Schools
- Jungle (terrain)
- Plant
- Plantation
- Rainforest
- Royal forest
- Temperate broadleaf and mixed forests
- Temperate coniferous forests
- Tree
- Tropical and subtropical coniferous forests
- Tropical and subtropical moist broadleaf forests
- vegetation
Activities related to forest
- Controlled burn
- Deforestation
- Forest engineering
- Logging and illegal logging
- Reforestation
- Shifting cultivation
Forests by country
Lists
- List of forests
- List of state forests in Australia
- List of trees in Canadian forests
- List of U.S. state forests
