The forest is a large area dominated by trees. Hundreds of more precisely defined forest definitions are used worldwide, incorporating factors such as tree density, tree height, land use, legal standing and ecological functions. According to the widely used Food and Agriculture Organization definition, forests cover 4 billion hectares (9.9 ÃÆ' - 10 9 hectare) (15 million square miles) or about 30 percent of world land in 2006.
Forests are the dominant terrestrial earth ecosystems, and are scattered throughout the world. Forests cover 75% of the gross primary productivity of the Earth's biosphere, and contain 80% of the biomass of plants on Earth. Net primary production is estimated at 21.9 gigatons of carbon per year for tropical forests, 8.1 for medium forest, and 2.6 for boreal forest.
Forests in various latitudes and heights form different ecozones: boreal forests near the poles, tropical forests near the equator and temperate forests in middle latitudes. Higher elevation areas tend to favor forests similar to those in higher latitudes, and the amount of rainfall also affects forest composition.
Human societies and forests affect each other in positive and negative ways. Forests provide ecosystem services to humans and serve as tourist attractions. Forests can also affect public health. Human activities, including harvesting of forest resources, can have a negative impact on forest ecosystems.
Video Forest
Definisi
Although forest is a common language term, there is no universally recognized definition, with over 800 forest definitions used worldwide. Although forests are usually defined by the existence of trees, under many definitions, areas that are entirely lacking trees may still be considered forests if trees grow in the past, will grow trees in the future, or legally defined as forests regardless of vegetation type.
There are three broad categories of forest definitions used: administration, land use, and land cover. Administrative definitions are based primarily on land law designations, and generally have little relation to land-based vegetation: lands legally designated as forests defined as forests even if there are no trees growing on them. The definition of land use is based on the main purpose that the land is functioning. For example, forests can be defined as any land used primarily for timber production. Under the definition of such land use, open roads or infrastructure within areas used for forestry, or areas within areas that have been logged with harvest, disease or fire are still considered forests even if they do not contain trees. The definition of land cover defines forests by species and density of growing vegetation on land. Such a definition usually defines forest as a tree area that grows over several thresholds. This threshold is usually the number of trees per area (density), the area under the canopy (cover canopy) or part of the land occupied by the cross section of the tree trunk (basal area). Under the definition of such land cover, and the area of ​​land is defined only as forest if the tree grows. Areas that fail to meet the definition of land cover may still be included below while immature trees are formed if they are expected to meet the definition at maturity.
Under the definition of land use, there are many variations in which the cutoff point lies between forest, forest, and savanna. Under some definitions, forests require very high tree canopy cover, from 60% to 100%, excluding savannahs and forests where trees have lower canopy cover. Another definition considers savanna as a forest type, and covers all areas with a tree canopy of more than 10%.
Some of the areas covered by trees are legally defined as agricultural areas, such as the Firs of Norway in Austrian forest laws when trees are planted as Christmas trees and below certain heights.
Maps Forest
Etymology
The word forest comes from Central English, from the ancient French forest (also forÃÆ'¨s ) "forest, a vast expanse covered by trees"; was first introduced in English as a word for wild land set aside for hunting without being defined for the existence of trees. Probably borrowed (perhaps through Frankish or Old High German) from the Medieval Latin word foresta "open wood", foresta used by the Carolingian clerks in the Capitularies of Charlemagne to refer specifically to the royal hunting grounds. This term is not endemic to the Romance language (eg original words for "forest" in Roman language evolved from the Latin "silva" "forest, wood" (English sylvan ); cf. Italian, Spanish, Portuguese selva ; Romanian silv? ; Ancient French selve ); and native languages ​​in Roman, such as Italian foresta , Spanish and Portuguese floresta , etc. everything is a loan from the French word.
The origins of the medieval Latin foresta are not clear. Some scholars claim this word comes from the Latin phrase End forestam silvam , which means "outer wood"; others claim the term is the exhausting words of Frank's forhist words "forest, forested state", assimilated with silamamam () (common practice among scribes Frank). Frankish *
The use of the word "forest" in English to show non-enclosure areas that are not inhabited are now considered ancient. The word was introduced by the Norman rulers of England as a legal term (appearing in Latin texts such as Magna Carta) which shows untreated areas legally set aside for hunting by feudal nobles (see Royal Forest).
These hunting forests need not be overgrown with trees, if at all. However, since hunting forests often include large forest areas, the word "forest" ultimately means forested land in general. At the beginning of the 14th century, the word appears in English text, indicating all three senses: the most common, legal terms and ancient usage. Another term used to mean "areas with high tree density" is wood, forest, wold, weald, holt, frith and firth . Unlike forest , these are all from Old English and are not borrowed from other languages. Some classifications now reserve the term forest for areas with more open space between trees and differentiate between forest, open forest , and closed forest based on the crown cover.
Evolution
The first known forests on Earth appeared at the end of the Devonian (about 380 million years ago), with the evolution of Archaeopteris . Archeopteris is a tree-like and fern-like plant, growing as high as 10 meters (33 feet). Archaeopteris quickly spread throughout the world, from the equator to sub-polar latitudes. Archaeopteris forms the first forest by being the first species known to scatter the shade because of its leaves and form the soil from its roots. Archaeopteris fall, dropping his leaf to the forest floor. Shade, soil, and forest duff from falling leaves creates the first forest. Disposable organic materials change the freshwater environment, slow it down and provide food. This freshwater fish is promoted.
Ecology
Forests cover 75% of the gross primary productivity of the Earth's biosphere, and contain 80% of the biomass of plants on Earth. Forest ecosystems can be found in all areas capable of sustaining tree growth, at altitudes to tree lines, unless the frequency of natural fires or other disturbances is too high, or where the environment has been altered by human activity.
Latitude 10 ° north and south of the equator is largely covered by tropical rainforests, and latitudes between 53 ° and 67 ° C have boreal forests. As a general rule, forests dominated by angiosperms ( broad-leaved forests) are rich in species rather than those dominated by gymnosperms ( conifer , montane , or < i> needleleaf forest ), although there are exceptions.
Forests sometimes contain many tree species in small areas (such as in tropical rainforests and deciduous forests), or relatively few species over large areas (eg, taiga and coniferous mountain forests). Forests are often home to many species of animals and plants, and biomass per unit area is high compared to other vegetation communities. Much of this biomass takes place underground in the root system and as a partially decomposed plant detritus. Wood components of the forest contain lignin, which is relatively slow to decompose compared to other organic materials such as cellulose or carbohydrates.
Components
The forest consists of many components that can be divided into two categories namely the components of biotic (alive) and abiotic (not alive). The living parts include trees, shrubs, vines, grasses and other herbaceous plants (not wood), mosses, algae, fungi, insects, mammals, birds, reptiles, amphibians, and microorganisms that live in plants and animals and on the ground.
Layers
The forest consists of many layers. Starting from the ground and moving up, the main layers of all forest types are the forest floor, the lower floor and the canopy. The layers that appear are in the tropical rain forest. Each layer has a different set of plants and animals depending on the availability of sunlight, moisture and food.
- The forest floor contains decaying leaves, animal feces, and dead trees. Damage on the forest floor forms new soil and provides nutrients for plants. The forest floor supports ferns, grass, mushrooms and tree seedlings.
- Understanding consists of shrubs, shrubs and young trees adapted to life in canopy shades.
- The canopy is formed by a collection of twigs, twigs and foliage from an adult tree. The dominant tree crown receives most of the sun. This is the most productive part of the tree in which the maximum food is produced. The canopy forms a shaded "umbrella" of shade throughout the forest.
- The pop-up layer is in the tropical rain forest and consists of several scattered trees towering over the canopy.
Type
Forests can be classified in various ways and with different degree of specificity. One such way is in terms of the biomes in which they exist, combined with the longevity of the leaves of the dominant species (whether they are evergreen or fall). Another difference is whether the forest is composed of broad-leaved trees, needle trees (needle leaf), or mixed.
- The boreal forests occupy the subarctic zone and are generally green and coniferous.
- The temperate zone supports large-leaved forests ( for example, , temperate forest) and coniferous coniferous forests ( eg, , temperate conifer forests and temperate rainforests medium). The warm climate zone supports the everlast evergreen forest, including the laurel forest.
- Tropical and subtropical forests include tropical and subtropical wet forests, tropical and subtropical dry forests, and tropical and subtropical conifer forests.
- Physiognomy classifies forests based on the overall physical structure or stage of development (eg old growth vs. second growth).
- Forests can also be classified more specifically based on existing predominant climates and tree species, which produce many different forest types (eg, Ponderosa/Douglas-fir pine forests).
The number of trees in the world, estimated by 2015, is 3 trillion, of which 1.4 trillion are in tropical or sub-tropical regions, 0.6 trillion in the medium zone, and 0.7 trillion in conifer bonsal forests. The estimate is approximately eight times higher than previously estimated, and is based on tree density measured at over 400,000 plots. This remains subject to a wide margin of error, not least because the sample is mainly from Europe and North America.
Forests can also be classified according to the number of human changes. The old-growth forest contains biodiversity patterns that are generally natural in established seral patterns, and they contain primarily native species of terrain and habitats. Conversely, secondary forests are forests that grow back after harvesting timber and may contain species originating from other areas or habitats.
Different global forest classification systems have been proposed, but none have received universal acceptance. The UNEP-WCMC forest category classification system is the simplification of more complex systems (eg, forest and forest subprojects 'UNESCO'). This system divides the world's forests into 26 major species, reflecting the climate zone as well as the main species of trees. These 26 main species can be reclassified into 6 broader categories: moderate temperate needleleaf; broadleaf and broadly mixed; tropical moist; tropical dry; trees and gardens are sparse; and forest plantations. Each category is described as a separate section below.
Flare requirement temperature
Most of the temperate forests needleleaf occupy higher latitudes in the Northern Hemisphere, as well as high altitude zones and some warm climates, especially in poor nutrient or poor soils. These forests are composed entirely of, or nearly so, coniferous species (Coniferophyta). In the Northern Hemisphere Pin , sprains Picea , larches Larix , firs Abies , Douglas firs Pseudotsuga and hemlocks Tsuga , make a canopy, but other taxa are also important. In the Southern Hemisphere, most coniferous species (members of Araucariaceae and Podocarpaceae) appear in mixtures with broadleaf species, and are classified as broadleaf and mixed forests. Lines wide and mixed
Massive wide-leaved and wide-leaved forest includes an important tree component in Anthophyta. They are generally characteristic of warm temperate latitudes, but extend to the cold climates, especially in the southern hemisphere. They include forest types like the mixed deciduous forests of the United States and their counterparts in China and Japan, the vast green rainforests of Japan, Chile and Tasmania, Australia's sclerophyllous forests, central Chile, Mediterranean and California, and southern Nothofagus beech forests in Chile and New Zealand.
Tropical moist
There are many types of humid tropical forests, with low-lying tropical rain forests, for example vÃÆ'¡rzea and igapÃÆ'Â hutan forests and terra firma forest in the Amazon Basin; peat swamp forests, dipterocarp forests of Southeast Asia; and high forest in the Congo Valley. Seasonal tropical forests, perhaps the best descriptions for the term "jungle" everyday, usually range from rainforest zones 10 degrees north or south of the equator, to Tropic of Cancer and Tropic of Capricorn. Forest located in the mountains are also included in this category, widely divided into upper and lower mountain formations based on physiognomy variations associated with altitude changes.
Tropical keris
Tropical dry forests are characteristic of areas in the tropics affected by seasonal droughts. Seasonal rainfall is usually reflected in the decline of the forest canopy, with most of the leafless trees for several months of the year. However, in some conditions, for example less fertile soils or drought regimes are less predictable, the proportion of evergreen species increases and forests are characterized as "sclerophyllous". Thorn forest, dense forest with a high-frequency thorny or prickly species, is found where prolonged drought, and especially where grazing animals abound. In very poor soil, and especially where fire or herbivore is a recurring phenomenon, savannas develop.
Lonely trees and parks
Rare trees and savannahs are forests with lower tree canopy cover. They occur primarily in the transition from forest to non-forest landscape. The two main zones where these ecosystems occur are in the boreal region and in the seasonally dry tropical regions. At high latitudes, to the north of the main boreal forest zone, growth conditions are inadequate to maintain a permanent cover of closed forests, resulting in rare and disconnected tree cover. This plant is called open taiga, open land, and forest tundra. A savanna is a mixed forest meadow ecosystem that is characterized by fairly wide trees spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herb layer that mainly consists of grass. Savannas maintains an open canopy despite having a high tree density.
Plantation
Plantation forests are generally intended for timber and pulpwood production. Generally mono-specific and/or composed of introduced tree species, these ecosystems are generally unimportant as habitats for native biodiversity. However, they can be managed in ways that enhance their biodiversity protection functions and they can provide ecosystem services such as maintaining nutritional capital, protecting watersheds and soil structures, and storing carbon.
Societal meaning
Forests provide a diversity of ecosystem services including converting carbon dioxide to oxygen and biomass, acting as carbon sinks, helping in regulating climate, purifying water, reducing natural hazards such as floods, and functioning as genetic reserves. Forests also serve as a source of wood and as a place of recreation.
Some researchers argue that forests not only provide benefits, but in some cases can also cost people. Forests can impose economic burdens, reduce the enjoyment of natural areas, reduce the production capacity of food from grazing land and cultivated land, reduce biodiversity reducing the availability of water for humans and wildlife, harboring harmful or destructive wildlife, and acting as human reservoirs and livestock diseases.
Forest management is often referred to as forestry. Forest management has changed considerably over the last few centuries, with rapid changes from the 1980s and then culminating in a practice now referred to as sustainable forest management. Forest ecologists concentrate on forest patterns and processes, usually with the aim of explaining causal relationships. Forestry experts who practice sustainable forest management focus on the integration of ecological, social and economic values, often in consultation with local communities and other stakeholders.
Humans have generally reduced the number of forests around the world. Anthropogenic factors that can affect forests include logging, urban spreading, human-caused forest fires, acid rain, invasive species, and slash and burn practices from swidden or shifting cultivation. The loss and re-growth of the forest leads to differences between two broad forest types, primary forest or old forest and secondary forest. There are also many natural factors that can cause changes in forests over time including wildfires, insects, diseases, weather, competition among species, etc. In 1997, the World Resources Institute noted that only 20% of the world's native forests remain large in number. intact tracts of undisturbed forest. More than 75% of these intact forests are located in three countries - Russian and Canadian boreal forests and Brazilian rain forests.
In 2010, the United Nations Food and Agriculture Organization reported that world deforestation, especially conversion of tropical forests to agricultural land, has declined over the past decade, but still continues at a high level in many countries. Globally, approximately 13 million hectares of forest are converted to other uses or lost naturally every year between 2000 and 2010 compared to about 16 million hectares per year during the 1990s. The study covered 233 countries and territories. Brazil and Indonesia, which experienced the highest forest loss in the 1990s, have significantly reduced their deforestation rates. China imposed a ban on logging, beginning in 1998, due to erosion and flooding it caused. In addition, ambitious tree planting programs in countries such as China, India, the United States and Vietnam - combined with natural forest expansion in some areas - have added more than seven million hectares of new forests each year. As a result, net forest loss decreased to 5.2 million hectares per year between 2000 and 2010, down from 8.3 million hectares annually in the 1990s. By 2015, a study for Climate Change shows that the trend has recently reversed, leading to "overall gain" in global biomass and forests. This advantage is mainly due to reforestation in China and Russia. However, the new forest is not entirely equivalent to old growth forest in terms of species diversity, carbon resistance and capture. On September 7, 2015, the United Nations Food and Agriculture Organization released a new study stating that, over the last 25 years, global deforestation rates have declined by 50% due to improved forest management and greater government protection.
Smaller forest areas in cities can be managed as urban forests, sometimes in public parks. This is often made for human benefit; Recovery Theory Caution argues that spending time in nature reduces stress and improves health, while forest schools and kindergartens help young people to develop social and scientific skills in the forest. This should normally be close to where the children live, for practical logistics.
Canada
Canada has approximately 4,020,000 square kilometers (1,550,000 sq.e., mi) of forest land. Over 90% of forest land is publicly owned and about 50% of the total forest area is allocated for harvest. These allocated areas are managed using the principles of sustainable forest management, which includes extensive consultations with local stakeholders. About eight percent of Canadian forests are legally protected from resource development. More forest areas - about 40 percent of the total forest area - are subject to various levels of protection through processes such as integrated land use planning or defined management areas such as certified forests.
As of December 2006, more than 1,237,000 square kilometers of Canadian forest land (about half of the global total) has been certified as sustainable management. Clearcutting, first used in the second half of the 20th century, is cheaper, but environmentally destructive, and companies are required by law to ensure that harvested areas are regenerated enough. Most Canadian provinces have regulations that limit the size of clearcut, although some older cutting blocks can reach up to 110 square kilometers (27,000 hectares) cut over several years.
Latvian
Latvia has about 3,270,000 hectares (12,626 sq mi) of forest land equivalent to 50.6% of the total Latvian region (24,938 sq mi). 1,510,000 hectares of forest land (46.3% of the total forest land) are owned by the public and 1,750,000 hectares of forest land (53.7% of total forest land) are in private hands. Latvia's forests have been steadily increasing for many years different from many other countries, largely due to the greening of unused land for agriculture. In 1935 there were only 1,757,000 hectares of forest, today it has risen by more than 150%. Birch is the most common tree in 28.2% followed by pine (26.9%), cypress (18.3%), gray alder (9.7%), aspen (8.0%), black alder (5.7%), oak/ash (1.2%) and finally hardwood composed the rest (2.0%).
United States
In the United States, most forests have historically been affected by humans to some extent, although in recent years improved forestry practices have helped to regulate or moderate large or large impacts. However, the United States Forest Service estimates a net loss of about 2 million hectares (4,942,000 hectares) between 1997 and 2020; these estimates include conversion of forest land to other uses, including urban and suburban development, as well as afforestation and natural returns from abandoned crops and pastoral land to forests. However, in many areas of the United States, forest areas are stable or increasing, especially in many northern states. The reverse problem of flooding has plagued the national forests, with loggers complaining that the lack of proper and thinning forest management has resulted in large forest fires.
Ground area
See also
References
External links
- The forest is in danger
- Full forest with maps and reports
- 2005 Global Forest Resource Assessment by Food and Agriculture Organization
- CoolForests.org - Cooling Planet Conservation
- The forest area is land under a tree stand that is grown naturally or at least 5 meters in place, whether productive or not, and excludes tree stands in agricultural production systems
- Forest area data (square km) from World Bank World Development Indicators, provided by Google
- Luck Baker, Andrew (November 18, 2008). "Forest first - Discovery 2008". BBC Online.
- "10 Most Threatened Hotspots of the World". International Conservation. February 2, 2011.
- Ã, Wilhelm Schlich and Gifford Pinchot (1911). "Forest and Forestry". EncyclopÃÆ'Â|dia Britannica (issue 11).
Source of the article : Wikipedia
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