About London Jobs, forests, etymology, distribution and classification of forests.

Forest ( London Jobs )

A forest ( London Jobs ) (also called a wood, woodland, wold, weald, holt, frith, or firth) is an area with a high density of trees ( London Jobs ). There are many definitions of a forest ( London Jobs ), 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 ( London Jobs ) is classified primarily by trees a forest (London Jobs ) ecosystem is defined intrinsically with additional species such as fungi.

Etymology

The word "forest" ( London Jobs ) comes from Middle English forest ( London Jobs ), from Old French forest  ( London Jobs )(also forès) "forest ( London Jobs ), 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" ( London Jobs ). Foresta  ( London Jobs ) 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" ( London Jobs ) in the Romance languages evolved out of the Latin word silva "forest, wood" ( London Jobs ); cf. Italian, Spanish, Portuguese selva; Romanian silvă; Old French selve); and cognates in Romance languages, such as Italian foresta ( London Jobs ), Spanish and Portuguese floresta ( London Jobs ), etc. are all ultimately borrowings of the French word. The exact origin of Medieval Latin foresta ( London Jobs ) is obscure. Some authorities claim the word derives from the Late Latin phrase forestam silvam, (London Jobs ) meaning "the outer wood"; others claim the term is a latinisation of the Frankish word *forhist "forest ( London Jobs ), wooded country", assimilated to forestam silvam (a common practise among Frankish scribes). Frankish *forhist is attested by Old High German forst "forest" ( London Jobs ), Middle Low German vorst "forest" ( London Jobs ), Old English fyrhþ "forest ( London Jobs ), 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 ( London Jobs )", from Proto-Indo-European *perk^wu- "a coniferous or mountain forest, wooded height". Uses of the word "forest" ( London Jobs ) 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 ( London Jobs )). These hunting forests ( London Jobs )were not necessarily wooded much, if at all. However, as hunting forests ( London Jobs ) did often include considerable areas of woodland, the word "forest" ( London Jobs ) 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 ( London Jobs ), 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 ( London Jobs ) 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 ( London Jobs ). As a general rule, forests dominated by angiosperms (broadleaf forests ( London Jobs )) are more species-rich than those dominated by gymnosperms (conifer, montane, or needleleaf forests ( London Jobs )), although exceptions exist.

Forests ( London Jobs ) sometimes contain many tree species only within a small area (as in tropical rain and temperate deciduous forests ( London Jobs )), or relatively few species over large areas (e.g., taiga and arid montane coniferous forests ( London Jobs )). Forests ( London Jobs ) 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 ( London Jobs ) contains lignin, which is relatively slow to decompose compared with other organic materials such as cellulose or carbohydrate.

Forests ( London Jobs ) are differentiated from woodlands by the extent of canopy coverage: in a forest ( London Jobs ), 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 ( London Jobs ). 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 ( London Jobs ) biomes are:

• rain forest ( London Jobs ) (tropical and temperate)
• taiga
• temperate hardwood forest ( London Jobs )
• tropical dry forest ( London Jobs )

Classification

Forests ( London Jobs ) 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 ( London Jobs ) composed predominantly of broadleaf trees, coniferous (needle-leaved) trees ( London Jobs ), or mixed.

• Boreal forests ( London Jobs ) occupy the subarctic zone and are generally evergreen and coniferous.
• Temperate zones support both broadleaf deciduous forests ( London Jobs ) (e.g., temperate deciduous forest ( London Jobs )) and evergreen coniferous forests ( London Jobs ) (e.g., Temperate coniferous forests (London Jobs ) and Temperate rainforests ( London Jobs )). Warm temperate zones support broadleaf evergreen forests ( London Jobs ), including laurel forests ( London Jobs ).
• Tropical and subtropical forests ( London Jobs ) include tropical and subtropical moist forests ( London Jobs ), tropical and subtropical dry forests ( London Jobs ), and tropical and subtropical coniferous forests (London Jobs ).
• Physiognomy classifies forests ( London Jobs ) based on their overall physical structure or developmental stage (e.g. old growth vs. second growth).
• Forests ( London Jobs ) can also be classified more specifically based on the climate and the dominant tree species present, resulting in numerous different forest ( London Jobs ) types (e.g., ponderosa pine/Douglas-fir forest ( London Jobs )).

A number of global forest ( London Jobs ) classification systems have been proposed, but none has gained universal acceptance.UNEP-WCMC's forest ( London Jobs ) category classification system is a simplification of other more complex systems (e.g. UNESCO's forest ( London Jobs ) and woodland 'subformations'). This system divides the world's forests ( London Jobs ) 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 ( London Jobs ) 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 ( London Jobs ), members of the Araucariaceae and Podocarpaceae, occur in mixtures with broadleaf species that are classed as broadleaf and mixed forests ( London Jobs ).

Temperate broadleaf and mixed

Temperate broadleaf and mixed forests ( London Jobs ) 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 ( London Jobs ) types as the mixed deciduous forests ( London Jobs ) of the USA and their counterparts in China and Japan, the broadleaf evergreen rain forests ( London Jobs ) of Japan, Chile and Tasmania, the sclerophyllous forests ( London Jobs ) of Australia, Central Chile, the Mediterranean and California, and the southern beech Nothofagus forests ( London Jobs ) of Chile and New Zealand.

Tropical moist

Tropical moist forests ( London Jobs ) include many different forest ( London Jobs ) types. The best known and most extensive are the lowland evergreen broadleaf rainforests include, for example: the seasonally inundated várzea and igapó forests ( London Jobs ) and the terra firma forests ( London Jobs ) of the Amazon Basin; the peat swamp forests ( London Jobs ) and moist dipterocarp forests ( London Jobs ) of Southeast Asia; and the high forests ( London Jobs ) of the Congo Basin. The forests ( London Jobs ) 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 ( London Jobs ) include cloud forest ( London Jobs ), those forests ( London Jobs ) 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 ( London Jobs ) also fall within this broad category, as do most of the tropical coniferous forests ( London Jobs )of Central America.

Tropical dry

Tropical dry forests ( London Jobs ) are characteristic of areas in the tropics affected by seasonal drought. The seasonality of rainfall is usually reflected in the deciduousness of the forest ( London Jobs ) 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 ( London Jobs )are characterised as "sclerophyllous". Thorn forest ( London Jobs ), 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 ( London Jobs ) with open canopies of 10-30% crown cover. They occur principally in areas of transition from forested ( London Jobs ) to non-forested ( London Jobs ) 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 ( London Jobs ) or taiga, growing conditions are not adequate to maintain a continuous closed forest ( London Jobs ) cover, so tree cover is both sparse and discontinuous. This vegetation is variously called open taiga, open lichen woodland, and forest ( London Jobs )tundra. It is species-poor, has high bryophyte cover, and is frequently affected by fire.

Forest ( London Jobs ) plantations

Forest ( London Jobs ) plantations, generally intended for the production of timber and pulpwood increase the total area of forest ( London Jobs ) 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 ( London Jobs ) for timber and fuelwood production.

Forest ( London Jobs ) categories

28 forest ( London Jobs ) 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 ( London Jobs ) types

1. Evergreen needleleaf forest ( London Jobs ) - Natural forest ( London Jobs ) with > 30% canopy cover, in which the canopy is predominantly (> 75%) needleleaf and evergreen.
2. Deciduous needleleaf forests ( London Jobs ) - Natural forests with > 30% canopy cover, in which the canopy is predominantly (> 75%) needleleaf and deciduous.
3. Mixed broadleaf/needleleaf forest ( London Jobs ) - Natural forest ( London Jobs ) 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 ( London Jobs ) - Natural forests ( London Jobs ) with > 30% canopy cover, the canopy being > 75% evergreen and broadleaf.
5. Deciduous broadleaf forest ( London Jobs ) - Natural forests ( London Jobs ) with > 30% canopy cover, in which > 75% of the canopy is deciduous and broadleaves predominate (> 75% of canopy cover).
6. Freshwater swamp forest ( London Jobs ) - Natural forests ( London Jobs ) 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 ( London Jobs ) - Natural forest ( London Jobs ) with > 30% canopy cover, in which the canopy is mainly composed of sclerophyllous broadleaves and is > 75% evergreen.
8. Disturbed natural forest ( London Jobs ) - Any forest ( London Jobs ) 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 ( London Jobs ) 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 ( London Jobs ) 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 ( London Jobs ) with > 30% canopy cover, which have been planted by people with species that occur naturally in that country.
12. *Unspecified forest ( London Jobs ) plantation - Forest ( London Jobs ) plantations showing extent only with no further information about their type, This data currently only refers to the Ukraine.
13. *Unclassified forest ( London Jobs ) data - Forest ( London Jobs ) data showing forest ( London Jobs ) 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 ( London Jobs ) type, hence 26 categories are quoted, not 28 shown here.

Tropical forest ( London Jobs ) types

1. Lowland evergreen broadleaf rain forest ( London Jobs ) - Natural forests ( London Jobs ) 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 ( London Jobs ) - Natural forests ( London Jobs ) with > 30% canopy cover, between 1200–1800 m altitude, with any seasonality regime and leaf type mixture.
3. Upper montane forest ( London Jobs ) - Natural forests ( London Jobs ) with > 30% canopy cover, above 1,800 m (5,906 ft) altitude, with any seasonality regime and leaf type mixture.
4. Freshwater swamp forest ( London Jobs ) - Natural forests ( London Jobs ) 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 ( London Jobs ) - Natural forests ( London Jobs ) 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 ( London Jobs ) - Natural forests ( London Jobs ) 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 ( London Jobs ) - Natural forest ( London Jobs ) with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, in which the canopy is predominantly (> 75%) needleleaf.
8. Mangroves - Natural forests ( London Jobs ) with > 30% canopy cover, composed of species of mangrove tree, generally along coasts in or near brackish or seawater.
9. Disturbed natural forest ( London Jobs ) - Any forest ( London Jobs ) 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 ( London Jobs ) - Natural forests ( London Jobs ) 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 ( London Jobs ) - Natural forests ( London Jobs ) 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 ( London Jobs ) - Natural forests ( London Jobs ) 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 ( London Jobs ) 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 ( London Jobs ) 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 ( London Jobs ) with > 30% canopy cover, which have been planted by people with species that occur naturally in that country.

Forest ( London Jobs ) loss and management

The scientific study of forest ( London Jobs ) species and their interaction with the environment is referred to as forest ( London Jobs ) ecology, while the management of forests ( London Jobs ) is often referred to as forestry ( London Jobs ). Forest ( London Jobs ) 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( London Jobs ) management. Forest ( London Jobs ) ecologists concentrate on forest ( London Jobs ) patterns and processes, usually with the aim of elucidating cause and effect relationships. Foresters ( London Jobs )who practice sustainable forest ( London Jobs ) 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 ( London Jobs ) include logging, urban sprawl, human-caused forest ( London Jobs ) fires, acid rain, invasive species, and the slash and burn practices of swidden agriculture or shifting cultivation. The loss and re-growth of forest ( London Jobs ) leads to a distinction between two broad types of forest ( London Jobs ), primary or old-growth forest ( London Jobs ) and secondary forest ( London Jobs ). There are also many natural factors that can cause changes in forests ( London Jobs ) over time including forest ( London Jobs ) fires, insects, diseases, weather, competition between species, etc. In 1997, the World Resources Institute recorded that only 20% of the world's original forests ( London Jobs ) remained in large intact tracts of undisturbed forest ( London Jobs ). More than 75% of these intact forests ( London Jobs )lie in three countries - the Boreal forests ( London Jobs ) of Russia and Canada and the rainforest of Brazil. In 2006 this information on intact forests ( London Jobs ) was updated using latest available satellite imagery.

Canada has about 4,020,000 square kilometres (1,550,000 sq mi) of forest ( London Jobs ) land. More than 90% of forest ( London Jobs ) land is publicly owned and about 50% of the total forest ( London Jobs ) area is allocated for harvesting. These allocated areas are managed using the principles of sustainable forest ( London Jobs ) management, which includes extensive consultation with local stakeholders. About eight percent of Canada’s forest ( London Jobs ) is legally protected from resource development (Global Forest ( London Jobs ) Watch Canada)(Natural Resources Canada). Much more forest ( London Jobs ) land — about 40 percent of the total forest ( London Jobs ) 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 ( London Jobs )(Natural Resources Canada)

By December 2006, over 1,237,000 square kilometers of forest ( London Jobs ) land in Canada (about half the global total) had been certified as being sustainably managed (Canadian Sustainable Forestry ( London Jobs )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 ( London Jobs ) have historically been affected by humans to some degree, though in recent years improved forestry ( London Jobs ) practices has helped regulate or moderate large scale or severe impacts. However, the United States Forest ( London Jobs ) Service estimates a net loss of about 2 million hectares (4,942,000 acres) between 1997 and 2020; this estimate includes conversion of forest (London Jobs ) land to other uses, including urban and suburban development, as well as afforestation and natural reversion of abandoned crop and pasture land to forest ( London Jobs ). 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 ( London Jobs ), with loggers complaining that a lack of thinning and proper forest ( London Jobs ) management has resulted in large forest ( London Jobs ) fires.

Old-growth forest ( London Jobs ) 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 ( London Jobs ) 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 ( London Jobs ), 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 ( London Jobs ) 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.