Tuesday, March 20, 2012

About macbook pro apple, forests, etymology, distribution and classification of forests.


Forest ( macbook pro apple )

A forest ( macbook pro apple ) (also called a wood, woodland, wold, weald, holt, frith, or firth) is an area with a high density of trees ( macbook pro apple ). There are many definitions of a forest ( macbook pro apple ), based on the various criteria.These plant communities cover approximately 9.4% of the Earth's surface (or 30% of total land area), though they once covered much more (about 50% 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 Earth's biosphere. Although a forest ( macbook pro apple ) is classified primarily by trees a forest ( macbook pro apple ) ecosystem is defined intrinsically with additional species such as fungi.

Etymology

The word "forest" ( macbook pro apple ) comes from Middle English forest ( macbook pro apple ), from Old French forest  ( macbook pro apple )(also forès) "forest ( macbook pro apple ), vast expanse covered by trees", believed to be a borrowing (probably via Frankish or Old High German) of the Medieval Latin word foresta "open wood" ( macbook pro apple ). Foresta  ( macbook pro apple ) was first used by Carolingian scribes in the Capitularies of Charlemagne to refer specifically to the king's royal hunting grounds. The term was not endemic to Romance languages (e.g. native words for "forest" ( macbook pro apple ) in the Romance languages evolved out of the Latin word silva "forest, wood" ( macbook pro apple ); cf. Italian, Spanish, Portuguese selva; Romanian silvă; Old French selve); and cognates in Romance languages, such as Italian foresta (macbook pro apple ), Spanish and Portuguese floresta ( macbook pro apple ), etc. are all ultimately borrowings of the French word. The exact origin of Medieval Latin foresta ( macbook pro apple ) is obscure. Some authorities claim the word derives from the Late Latin phrase forestam silvam, ( macbook pro apple ) meaning "the outer wood"; others claim the term is a latinisation of the Frankish word *forhist "forest ( macbook pro apple ), wooded country", assimilated to forestam silvam (a common practise among Frankish scribes). Frankish *forhist is attested by Old High German forst "forest" ( macbook pro apple ), Middle Low German vorst"forest" ( macbook pro apple ), Old English fyrhþ "forest ( macbook pro apple ), woodland, game preserve, hunting ground", and Old Norse fýri "coniferous forest", all of which derive from Proto-Germanic *furχísa-, *furχíþja- "a fir-wood, coniferous forest ( macbook pro apple )", from Proto-Indo-European *perkwu- "a coniferous or mountain forest, wooded height". Uses of the word "forest" ( macbook pro apple ) in English to denote any uninhabited area of non-enclosure are now considered archaic. The word was introduced by the Norman rulers of England as a legal term (appearing in Latin texts like the Magna Carta) denoting an uncultivated area legally set aside for hunting by feudal nobility (see Royal Forest ( macbook pro apple )). These hunting forests ( macbook pro apple ) were not necessarily wooded much, if at all. However, as hunting forests (macbook pro apple ) did often include considerable areas of woodland, the word "forest" ( macbook pro apple ) eventually came to mean wooded land more generally.By the start of the fourteenth century the word appeared in English texts, indicating all three senses: the most common one, the legal term and the archaic usage.
Other terms used to mean "an area with a high density of trees" are wood, woodland, wold, weald, holt, frith and firth. Unlike forest ( macbook pro apple ), these are all derived from Old English and were not borrowed from another language. Some now reserve the term woodland for an area with more open space between trees.

Distribution

Forests ( macbook pro apple ) can be found in all regions capable of sustaining tree growth, at altitudes up to the tree line, except where natural fire frequency or other disturbance is too high, or where the environment has been altered by human activity.
The latitudes 10° north and south of the Equator are mostly covered in tropical rainforest, and the latitudes between 53°N and 67°N have boreal forest ( macbook pro apple ). As a general rule, forests dominated by angiosperms (broadleaf forests ( macbook pro apple )) are more species-rich than those dominated by gymnosperms (conifer, montane, or needleleaf forests ( macbook pro apple )), although exceptions exist.
Forests ( macbook pro apple ) sometimes contain many tree species only within a small area (as in tropical rain and temperate deciduous forests ( macbook pro apple )), or relatively few species over large areas (e.g., taiga and arid montane coniferous forests ( macbook pro apple )). Forests ( macbook pro apple ) are often home to many animal and plant species, and biomass per unit area is high compared to other vegetation communities. Much of this biomass occurs below ground in the root systems and as partially decomposed plant detritus. The woody component of a forest ( macbook pro apple ) contains lignin, which is relatively slow to decompose compared with other organic materials such as cellulose or carbohydrate.
Forests ( macbook pro apple ) are differentiated from woodlands by the extent of canopy coverage: in a forest ( macbook pro apple ), the branches and the foliage of separate trees often meet or interlock, although there can be gaps of varying sizes within an area referred to as forest ( macbook pro apple ). A woodland has a more continuously open canopy, with trees spaced further apart, which allows more sunlight to penetrate to the ground between them (also see: savanna).
Among the major forested ( macbook pro apple ) biomes are:

Classification

Forests ( macbook pro apple ) 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). Another distinction is whether the forests ( macbook pro apple ) composed predominantly of broadleaf trees, coniferous (needle-leaved) trees ( macbook pro apple ), or mixed.
A number of global forest ( macbook pro apple ) classification systems have been proposed, but none has gained universal acceptance.UNEP-WCMC's forest ( macbook pro apple ) category classification system is a simplification of other more complex systems (e.g. UNESCO's forest ( macbook pro apple ) and woodland 'subformations'). This system divides the world's forests ( macbook pro apple ) into 26 major types, which reflect climatic zones as well as the principal types of trees. These 26 major types can be reclassified into 6 broader categories: temperate needleleaf; temperate broadleaf and mixed; tropical moist; tropical dry; sparse trees and parkland; and forest plantations. Each category is described as a separate section below.

Temperate needleleaf

Temperate needleleaf forests mostly occupy the higher latitude regions of the northern hemisphere, as well as high altitude zones and some warm temperate areas, especially on nutrient-poor or otherwise unfavourable soils. These forests ( macbook pro apple ) are composed entirely, or nearly so, of coniferous species (Coniferophyta). In the Northern Hemisphere pines Pinus, spruces Picea, larches Larix, silver firs Abies, Douglas firs Pseudotsuga and hemlocks Tsuga, make up the canopy, but other taxa are also important. In the Southern Hemisphere most coniferous trees ( macbook pro apple ), members of the Araucariaceae and Podocarpaceae, occur in mixtures with broadleaf species that are classed as broadleaf and mixed forests ( macbook pro apple ).

Temperate broadleaf and mixed

Temperate broadleaf and mixed forests ( macbook pro apple ) include a substantial component of trees in the Anthophyta. They are generally characteristic of the warmer temperate latitudes, but extend to cool temperate ones, particularly in the southern hemisphere. They include such forest ( macbook pro apple ) types as the mixed deciduous forests ( macbook pro apple ) of the USA and their counterparts in China and Japan, the broadleaf evergreen rain forests ( macbook pro apple ) of Japan, Chile and Tasmania, the sclerophyllous forests ( macbook pro apple ) of Australia, Central Chile, the Mediterranean and California, and the southern beech Nothofagus forests ( macbook pro apple ) of Chile and New Zealand.

Tropical moist

Tropical moist forests ( macbook pro apple ) include many different forest ( macbook pro apple ) types. The best known and most extensive are the lowland evergreen broadleaf rainforests include, for example: the seasonally inundated várzea and igapó forests ( macbook pro apple ) and the terra firma forests ( macbook pro apple ) of the Amazon Basin; the peat swamp forests ( macbook pro apple ) and moist dipterocarp forests (macbook pro apple ) of Southeast Asia; and the high forests ( macbook pro apple ) of the Congo Basin. The forests ( macbook pro apple ) of tropical mountains are also included in this broad category, generally divided into upper and lower montane formations on the basis of their physiognomy, which varies with altitude. The montane forests ( macbook pro apple ) include cloud forest ( macbook pro apple ), those forests ( macbook pro apple ) at middle to high altitude, which derive a significant part of their water budget from cloud, and support a rich abundance of vascular and nonvascular epiphytes. Mangrove forests ( macbook pro apple ) also fall within this broad category, as do most of the tropical coniferous forests ( macbook pro apple ) of Central America.

Tropical dry

Tropical dry forests ( macbook pro apple ) are characteristic of areas in the tropics affected by seasonal drought. The seasonality of rainfall is usually reflected in the deciduousness of the forest ( macbook pro apple )canopy, with most trees being leafless for several months of the year. However, under some conditions, e.g. less fertile soils or less predictable drought regimes, the proportion of evergreen species increases and the forests (macbook pro apple ) are characterised as "sclerophyllous". Thorn forest ( macbook pro apple ), a dense forest of low stature with a high frequency of thorny or spiny species, is found where drought is prolonged, and especially where grazing animals are plentiful. On very poor soils, and especially where fire is a recurrent phenomenon, woody savannas develop (see 'sparse trees and parkland').

Sparse trees and parkland

Sparse trees and parkland are forests ( macbook pro apple ) with open canopies of 10-30% crown cover. They occur principally in areas of transition from forested ( macbook pro apple ) to non-forested ( macbook pro apple ) landscapes. The two major zones in which these ecosystems occur are in the boreal region and in the seasonally dry tropics. At high latitudes, north of the main zone of boreal forest ( macbook pro apple ) or taiga, growing conditions are not adequate to maintain a continuous closed forest ( macbook pro apple ) cover, so tree cover is both sparse and discontinuous. This vegetation is variously called open taiga, open lichen woodland, and forest ( macbook pro apple ) tundra. It is species-poor, has high bryophyte cover, and is frequently affected by fire.

Forest ( macbook pro apple ) plantations

Forest ( macbook pro apple ) plantations, generally intended for the production of timber and pulpwood increase the total area of forest ( macbook pro apple ) worldwide. Commonly mono-specific and/or composed of introduced tree species, these ecosystems are not generally important as habitat for native biodiversity. However, they can be managed in ways that enhance their biodiversity protection functions and they are important providers of ecosystem services such as maintaining nutrient capital, protecting watersheds and soil structure as well as storing carbon. They may also play an important role in alleviating pressure on natural forests (macbook pro apple ) for timber and fuelwood production.

Forest ( macbook pro apple ) categories

28 forest ( macbook pro apple ) categories are used to enable the translation of forest types from national and regional classification systems to a harmonised global one:

Temperate and boreal forest ( macbook pro apple ) types

  1. Evergreen needleleaf forest ( macbook pro apple ) - Natural forest ( macbook pro apple ) with > 30% canopy cover, in which the canopy is predominantly (> 75%) needleleaf and evergreen.
  2. Deciduous needleleaf forests ( macbook pro apple ) - Natural forests with > 30% canopy cover, in which the canopy is predominantly (> 75%) needleleaf and deciduous.
  3. Mixed broadleaf/needleleaf forest ( macbook pro apple ) - Natural forest ( macbook pro apple ) with > 30% canopy cover, in which the canopy is composed of a more or less even mixture of needleleaf and broadleaf crowns (between 50:50% and 25:75%).
  4. Broadleaf evergreen forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, the canopy being > 75% evergreen and broadleaf.
  5. Deciduous broadleaf forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, in which > 75% of the canopy is deciduous and broadleaves predominate (> 75% of canopy cover).
  6. Freshwater swamp forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, composed of trees with any mixture of leaf type and seasonality, but in which the predominant environmental characteristic is a waterlogged soil.
  7. Sclerophyllous dry forest ( macbook pro apple ) - Natural forest ( macbook pro apple ) with > 30% canopy cover, in which the canopy is mainly composed of sclerophyllous broadleaves and is > 75% evergreen.
  8. Disturbed natural forest ( macbook pro apple ) - Any forest ( macbook pro apple ) type above that has in its interior significant areas of disturbance by people, including clearing, felling for wood extraction, anthropogenic fires, road construction, etc.
  9. Sparse trees and parkland - Natural forests ( macbook pro apple ) in which the tree canopy cover is between 10-30%, such as in the steppe regions of the world. Trees of any type (e.g., needleleaf, broadleaf, palms).
  10. Exotic species plantation - Intensively managed forests ( macbook pro apple ) with > 30% canopy cover, which have been planted by people with species not naturally occurring in that country.
  11. Native species plantation - Intensively managed forests ( macbook pro apple ) with > 30% canopy cover, which have been planted by people with species that occur naturally in that country.
  12. *Unspecified forest ( macbook pro apple ) plantation - Forest ( macbook pro apple ) plantations showing extent only with no further information about their type, This data currently only refers to the Ukraine.
  13. *Unclassified forest ( macbook pro apple ) data - Forest ( macbook pro apple ) data showing forest ( macbook pro apple ) extent only with no further information about their type.
Those marked * have been created as a result of data holdings which do not specify the forest ( macbook pro apple ) type, hence 26 categories are quoted, not 28 shown here.

Tropical forest ( macbook pro apple ) types

  1. Lowland evergreen broadleaf rain forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, below 1,200 m (3,937 ft) altitude that display little or no seasonality, the canopy being >75% evergreen broadleaf.
  2. Lower montane forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, between 1200–1800 m altitude, with any seasonality regime and leaf type mixture.
  3. Upper montane forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, above 1,800 m (5,906 ft) altitude, with any seasonality regime and leaf type mixture.
  4. Freshwater swamp forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, composed of trees with any mixture of leaf type and seasonality, but in which the predominant environmental characteristic is a waterlogged soil.
  5. Semi-evergreen moist broadleaf forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, below 1,200 m (3,937 ft) altitude in which between 50-75% of the canopy is evergreen, > 75% are broadleaves, and the trees display seasonality of flowering and fruiting.
  6. Mixed broadleaf/needleleaf forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, in which the canopy is composed of a more or less even mixture of needleleaf and broadleaf crowns (between 50:50% and 25:75%).
  7. Needleleaf forest ( macbook pro apple ) - Natural forest ( macbook pro apple ) with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, in which the canopy is predominantly (> 75%) needleleaf.
  8. Mangroves - Natural forests ( macbook pro apple ) with > 30% canopy cover, composed of species of mangrove tree, generally along coasts in or near brackish or seawater.
  9. Disturbed natural forest ( macbook pro apple ) - Any forest ( macbook pro apple ) type above that has in its interior significant areas of disturbance by people, including clearing, felling for wood extraction, anthropogenic fires, road construction, etc.
  10. Deciduous/semi-deciduous broadleaf forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, below 1,200 m (3,937 ft) altitude in which between 50-100% of the canopy is deciduous and broadleaves predominate (> 75% of canopy cover).
  11. Sclerophyllous dry forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, in which the canopy is mainly composed of sclerophyllous broadleaves and is > 75% evergreen.
  12. Thorn forest ( macbook pro apple ) - Natural forests ( macbook pro apple ) with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, in which the canopy is mainly composed of deciduous trees with thorns and succulent phanerophytes with thorns may be frequent.
  13. Sparse trees and parkland - Natural forests ( macbook pro apple ) in which the tree canopy cover is between 10-30%, such as in the savannah regions of the world. Trees of any type (e.g., needleleaf, broadleaf, palms).
  14. Exotic species plantation - Intensively managed forests ( macbook pro apple ) with > 30% canopy cover, which have been planted by people with species not naturally occurring in that country.
  15. Native species plantation - Intensively managed forests ( macbook pro apple ) with > 30% canopy cover, which have been planted by people with species that occur naturally in that country.

Forest ( macbook pro apple ) loss and management

The scientific study of forest ( macbook pro apple ) species and their interaction with the environment is referred to as forest ( macbook pro apple ) ecology, while the management of forests ( macbook pro apple ) is often referred to as forestry ( macbook pro apple ). Forest ( macbook pro apple ) management has changed considerably over the last few centuries, with rapid changes from the 1980s onwards culminating in a practice now referred to as sustainable forest ( macbook pro apple ) management. Forest ( macbook pro apple ) ecologists concentrate on forest ( macbook pro apple ) patterns and processes, usually with the aim of elucidating cause and effect relationships. Foresters ( macbook pro apple ) who practice sustainable forest ( macbook pro apple ) management focus on the integration of ecological, social and economic values, often in consultation with local communities and other stakeholders.
Anthropogenic factors that can affect forests ( macbook pro apple ) include logging, urban sprawl, human-caused forest ( macbook pro apple ) fires, acid rain, invasive species, and the slash and burn practices of swidden agriculture or shifting cultivation. The loss and re-growth of forest ( macbook pro apple ) leads to a distinction between two broad types of forest ( macbook pro apple ), primary or old-growth forest ( macbook pro apple )and secondary forest ( macbook pro apple ). There are also many natural factors that can cause changes in forests ( macbook pro apple ) over time including forest ( macbook pro apple ) fires, insects, diseases, weather, competition between species, etc. In 1997, the World Resources Institute recorded that only 20% of the world's original forests ( macbook pro apple ) remained in large intact tracts of undisturbed forest ( macbook pro apple ). More than 75% of these intact forests ( macbook pro apple ) lie in three countries - the Boreal forests ( macbook pro apple ) of Russia and Canada and the rainforest of Brazil. In 2006 this information on intact forests ( macbook pro apple ) was updated using latest available satellite imagery.
Canada has about 4,020,000 square kilometres (1,550,000 sq mi) of forest ( macbook pro apple ) land. More than 90% of forest ( macbook pro apple ) land is publicly owned and about 50% of the total forest (macbook pro apple ) area is allocated for harvesting. These allocated areas are managed using the principles of sustainable forest ( macbook pro apple ) management, which includes extensive consultation with local stakeholders. About eight percent of Canada’s forest ( macbook pro apple ) is legally protected from resource development (Global Forest ( macbook pro apple ) Watch Canada)(Natural Resources Canada). Much more forest ( macbook pro apple ) land — about 40 percent of the total forest ( macbook pro apple ) land base — is subject to varying degrees of protection through processes such as integrated land-use planning or defined management areas such as certified forests ( macbook pro apple ) (Natural Resources Canada)
By December 2006, over 1,237,000 square kilometers of forest ( macbook pro apple ) land in Canada (about half the global total) had been certified as being sustainably managed (Canadian Sustainable Forestry (macbook pro apple ) Certification Coalition). Clearcutting, first used in the latter half of the 20th century, is less expensive, but devastating to the environment and companies are required by law to ensure that harvested areas are adequately regenerated. Most Canadian provinces have regulations limiting the size of clearcuts, although some older clearcuts can range upwards of 110 square kilometres (27,000 acres) in size which were cut over several years. China instituted a ban on logging, beginning in 1998, due to the destruction caused by clearcutting. Selective cutting avoids the erosion, and flooding, that result from clearcutting.
In the United States, most forests ( macbook pro apple ) have historically been affected by humans to some degree, though in recent years improved forestry ( macbook pro apple ) practices has helped regulate or moderate large scale or severe impacts. However, the United States Forest ( macbook pro apple ) Service estimates a net loss of about 2 million hectares (4,942,000 acres) between 1997 and 2020; this estimate includes conversion of forest ( macbook pro apple ) land to other uses, including urban and suburban development, as well as afforestation and natural reversion of abandoned crop and pasture land to forest ( macbook pro apple ). However, in many areas of the United States, the area of forest is stable or increasing, particularly in many northern states. The opposite problem from flooding has plagued national forests ( macbook pro apple ), with loggers complaining that a lack of thinning and proper forest ( macbook pro apple ) management has resulted in large forest ( macbook pro apple ) fires.
Old-growth forest ( macbook pro apple ) contains mainly natural patterns of biodiversity in established seral patterns, and they contain mainly species native to the region and habitat. The natural formations and processes have not been affected by humans with a frequency or intensity to change the natural structure and components of the habitat. Secondary forest ( macbook pro apple ) contains significant elements of species which were originally from other regions or habitats.
Smaller areas of woodland in cities may be managed as Urban forestry ( macbook pro apple ), sometimes within public parks. These are often created for human benefits; Attention Restoration Theory argues that spending time in nature reduces stress and improves health, while forest ( macbook pro apple ) schools and kindergartens help young people to develop social as well as scientific skills in forests. These typically need to be close to where the children live, for practical logistics.
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