The deforestation is the phenomenon of regression of covered surfaces of Forêt. It results from the actions of Déboisement then of Défrichement, related to the extension of the Ground S agricultural S. It also results from a exploitation excessive or anarchistic from some forest gasolines and Urbanisation.

Because of tolerance many Country, like the Brazil or Madagascar, with respect to the development of agriculture in wooded areas, current deforestation relates to especially the forests Tropical are. In 2005, it was described as “alarming” by FAO.

The destruction of the forest is responsible for 20% of the emissions of Gaz to greenhouse effect. It is one of the important components which cause the Climate warming.

Some figures

; Rough deforestation According to FAO, approximately 13 million hectares of forest disappears annually on Earth. It is the equivalent of the surface of the England which disappears annually, that is to say 1 football field each second. It is the equivalent on the surface of 86% of the French forest which disappears thus each year.

; Net losses “net loss” of forest, which takes account of the plantations of trees which replace the forests rose to 8,9 ha/an million estimated between 1990 and 2000, and with 7,3 million hectares/an of 2000 with 2005 (a surface corresponding to that of the Sierra Leone or Panama). The rate/rhythm of deforestation slightly decreased thus and corresponds to an annual net loss of 0,18% of the forests of the world.

; The primary forests While being based on the figures sent by the states to FAO, the report/ratio FRA 2005 of FAO concludes that following deforestation or with selective cuts, the artificial plantations of trees further increased covering in 2005 nearly 5% of the wooded surfaces of the world; the primary forests or without visible signs of human activities present or last do not constitute any more in 2005 but 36% of the world forest surface, continuing to disappear or be modified per annum at a rate of 6 million hectares of 2000 to 2005.

Part of the cuts will be followed of a forest regeneration, often slow or poor, another part will be planted trees of revenues (Eucalyptus, Palmier with oil, Hévéa, Cacao yer, The ier, Café ist.) but in Amazonia, the greatest part is transformed into culture of Soja and elsewhere into fields (Approximately 75% of the forest losses are due to the agricultural expansion). In tropical zone, these fields are degraded quickly, to evolve to a Savane or the Désertification.

Olfield suggested into 1998 that nearly 10 percent of the species of trees known, that is to say approximately 7.000 species, are threatened of extinction in the short or medium term (primarily in tropical zone), and for each species, it is a richness larger Génétique still which is lost.

History

Deforestation is old. It started according to Williams as of the end of prehistory, with a clear spatiotemporelle correlation between retreat of the forest and density of the human population in zone moderated, even if rather dense populations also locally could live in the forest and of the forest without destroying it, in tropical zone (ex: Amerindian S, populations of Black Africa and current the Indonesia)

; In Europe

Deforestation accompanied the man almost everywhere where it was sédentarisé, agriculture remaining still today the leading cause of deforestation followed closely by the requirement in Firewood. It is old. Fires of clearing contributed much to it. The axes of Silex reconstituted by the prehistorians are shown very effective, but it is especially the work of the loggers and sawyers of the Moyen-âge, as well as the techniques of transport by Flottage of wood which made move back the medieval forest to feed the forging mills, the chimneys, the furnaces, the coalmen and construction.

The deforestation carried out in Europe during the the Middle Ages in order to extend the arable lands, made pass France of Jules César, timbered with more than 90% with less than 15% at the end of the 19th century. In 1850, the clearing gains the slopes, until the tops of medium mountains. Quickly the forests of plain of the moderate zones of Asia and Europe are degraded in the poor Taillis and separated by many kilometers.

; Deforestation and afforestation in France It is estimated that at the time of Vercingétorix, the France was covered with forests to more than 90%, that is to say approximately 400.000 square kilometres. Today only 23% are enforestés. The rate of timbering increases since more than one century, especially on average mountain and mountain, but with natural forests often less and ecologically fragmented.

In France, Colbert (1619-1683) gave a cost of stop to deforestation and ordered the plantations of forests for naval construction, but the requirements out of wood caused a constant exploitation of the forest which at the beginning of the 19th century, as a ecosystem " was almost completely destroyed. One needed severe lawful measurements (forest Code of 1827, and large the afforestation of the Second Empire 1825-1880, and a law on the restorations of the grounds of mountain (1860) to change what (Chateaubriand) described as a " deserted pretense of "

; In Americas

Before the arrival of Europeans to the the United States, about half of surface of the the United States was covered by a primary Forêt.

World distribution

In second half of the 20th century, the 3 great zones of active deforestation, by decreasing size of surfaces concerned are: the Amazonia, the equatorial Africa and the zone Malaysia/Indonesia in Asia.

According to FAO, it is in South America that the net loss of forests was highest of 2000 to 2005 (approximately 4,3 million hectares per annum).

The first two destroying countries of forests for 2000-2005 are:

1. the Brazil, with 3,1 destroyed ha/an million (0,6% of deforestation)
2. the Indonesia, with 1,8 ha/an million destroyed (2% of deforestation)

Nearly two thirds of the forests of the world have been concerned with a strong deforestation for two centuries (the century being a “not time” runs for the reconstitution of a forest ecosystem which is carried out over several centuries, even more than 1000 years on the most difficult grounds), with an aggravation of the phenomenon mainly in 8 countries: Australia, Brazil, China, India, Indonesia, Federation of Russia, Peru, Democratic republic of Congo. The the United States and the Canada stabilized deforestation, but the forest there often was very artificialisée. Elsewhere, as in Europe and with the Japan, the forest is stable or gains surface (in France in particular), but it loses its quality in term of biodiversity and especially of ecological Intégrité, in particular because of the ecological Fragmentation by the roads and of the gasoline plantations of revenues. In addition, these last countries contribute to deforestation while being among the first tropical importers of wood and Soja (cultivated in the place of destroyed tropical forests).

Hope notes? In 2007, according to a dispatch of Reuters, deforestation would be “in Net retreat” in the Amazon forest. The rate of deforestation would have decreased by approximately a third during the last twelve months in the Amazon forest to low reach its level since the years 1970, according to remarks made by the Brazilian ministry of the environment.

Causes

Human activities

• the use of the ground :

- The agricultural use of the ground: 60% of deforestation are due to the Cultures on denshering, with its exploitation during two or three years, and with its abandonment. These grounds are indeed very poor and undergo important a erosion. After abandonment, the farmer starts again elsewhere, and so on. Soya is the principal culture concerned. The overgrazing is also in question: the cattle destroys the vegetation and prevents its regeneration. The Brazilian oxen, for example, encroach in this way largely on the forest.

- The clearing of the natural forests and their replacement by mono plantations specific more profitable causes a considerable loss in biodiversity and weakens the vegetation (see biotic factors).

- Lastly, the Urbanization, mitage of the natural zones, alteration work (Regrouping S compartmental) and the infrastructures (highways, access paths…), exploitation of the mining resources (causing the poisoning of the ground, with the conceivable consequences on the vegetation: the mine of Tightened back Carajás in Brazil thus destroyed 150.000 km ² of forest) and the hydroelectric stoppings have a strong impact on the forests.

• the nondurable exploitation of the forest and agricultural resources is of course another serious problem. The absence of plans of long-term management involves the disappearance of the forests: the forestry companies cross to white without preoccupations with an afforestation, and no natural regeneration is possible (see consequences: erosion of the grounds).

Moreover, the unwise exploitation of a piece strongly damages the vegetation around: thus, for a tree shot down 40 others are damaged. 20% of the deforestations come from it.

• the need of wood : the firewood harvest in the countries of the South accounts for 56% of the world wood exploitation. These individual, specific and surface taking away, thus cause together great upheavals.

In North, the requirements out of structural timber and paper feed the plundering of the forest resources of the South.

• the fires due to Clearing of undergrowth S, the cultures on denshering, hunting, the fight against “harmful” species, to the elimination of waste, vandalism, unconsciousness or randomly can destroy in a few hours of enormous surfaces, as it was the case with Kalimantan (Borneo) where 3.5 million ha burned…

• the ''' atmospheric pollution ''', of the water or the grounds (in particular by plant health Produced ) can extend on whole areas and cause the weakening even death of all the vegetation touched, without hope of even anthropic regeneration before tens of years.

• tourism and a too important frequentation slow down regeneration and pack the grounds.

• the successive wars as with the Vietnam in 1973 when 22.000 km ², are 23% of the wooded surface of the country, were destroyed have of course an influence more than harmful.

Indirect causes

• Social difficulties, poverty.
• demographic Explosion
• Absence of regulation within the countries concerned, which rises from the ignorance and the disinterest of the actors and the consumers.
• important Consumption in the countries developed, of cattle or poultry, nourished by the Soya cultivated with the Brazil.
• Consumption of furniture in Wood not respecting a forest good management.

Natural factors

Nowadays, the natural factors having an influence on forest cover are:

• the diseases and the mushrooms are helped by the presence of specific mono cultures, even of cultures made up of trees clones. Indeed when a tree is reached all the settlement follows because each tree has the same vulnerability.

The graphiose of the Elm ( Ceratocystis ulmi ) thus responsible of died for the near total of the Elms of Europe during the years 1980.

• the proliferations of species like the large herbivores (supported by the disappearance of their predatory) or the phytophagous insects (supported by the specific mono cultures and climate warming) can be extremely destroying, as in Quebec where the Tortrix of the buds of the virginal caused between 1938 and 1958 the death of 60% of the fir trees (Abies balsamea) and of 20% of the virginals (Picea glauca) although these epidemics occur in gigantic natural forests and not in monospecific plantations. In 1975,35 million hectares were touched. These epidemics are recurring in northern forest because they are sources of renovation of the forest but it is estimated that the warming of planet could accelerate this process. In the South of France, years 2003-2006 were very hot and dry causing epidemics devastators in the settlements of common spruces. The local foresters estimate that the spruce, introduces into the South Massif Central and in the Pyrenees in the years 1950-60, could become a remainder from here a few years creating coniferous a timber shortage said " blancs" useful for the paper mill.

• the climatic risks

• Dryness: who creates favorable conditions with the development of the Incendie S.
• dry Orages: who create with their flashes and induced Vent S of the spectacular forest fires in the northern forests (Canada [http://www.nrcan-rncan.gc.ca/cfs-scf/science/prodserv/firereport/archives_f.php?graph_year=05&graph=02] , the United States, Siberia Orientale and Northern of China) like in the forest tropical dry at the time of phenomena macroclimatic (El Nino in Indonesia). The storm of 1999 for example destroyed 160 million m ³ of wood only in France.

• Natural disasters : for example, the volcanic eruption of the Holy mount Helens with the the United States, caused the massive destruction several tens of square kilometers of wood

Human factors

The Man contributes to the deforestation in many manners:

• more locally, for the mining exploitation in the open air which requires white cuts “” and zones of rejections of polluted water or “sterile” , or following certain techniques of Orpaillage
• Indirectement, following the anthropic share of the Climate warming (drynesses which causes forest fires or worsen the consequences of them).
• the share of responsibility for the exploitation of wood makes debate. The direct taxation of the international market of wood tropical is not dominant in term of direct impact in Amazonia, Asia and Africa). However;

- when a tree of the primary forest is cut, several hundreds of others are damaged or cut to reach

it - It is advisable to distinguish the traditional forestry development (selective) from the cuts of recovery (in the event of deforestation for agriculture or mining) which are in fact of the cuts of opportunity.

- the transformations of primary forests into timberings cultivated, sometimes monospecific continued and even locally amplified (in Tasmanie for example) since the Sommet of Rio.

- It should be held account owing to the fact that in tropical zone, tens of thousands of Kilometers of tracks and roads forest (and sometimes tailboards) become means of penetrating further and very easily the forest for the poor hunters and peasants who will burn the forest to convert it into land arable.

- large hundreds hydroelectric stoppings ennoyé very rich forest surfaces ecologically, but especially, they made the rivers more regular and easily navigable (by drowning the “jumps” ), facilitating the access to the zones far away from the forest more accessible, just as the roads built to build them and reach it or the close-cropped cuts made for the passage of the lines high voltage.

Lastly, the Helicopter, GPS, the satellite imagery and progress of the communication without wire also locally facilitated the illegal exploitation and the destruction of the forests.

It is in fine the conversion of the forests on the agricultural surfaces which is historically the first factor of deforestation of the tropical zones. (cultures and/or pastures, are financially more productive and interesting that the forest for the peasants, even if it is known that the forests are essential to the balance of Nature and that the concept of productivity does not have a direction if it disregards biological balance. The situation is complicated by the absence of international convention on the Forest, the difficult control of the illegal activities in tropical zones, the existence of a traffic facilitated by corruption, and the fact that deforestation can give the impression in the short run to improve the balance of poor payments of country by export, to cause tax and incomes for the state or of the communities, by creating a new economic activity (employment, returned,…)

Some experiments of Agroforesterie including breedings in forest medium take place, of which in Black Forest, as that was done in Europe with the Moyen-âge. Remain to study the effects of the Sylvopastoralisme in order to adjust the density of the cattle and the residence time to the capacity of the medium to regenerate itself, because the Vache S and Chevaux (of the Pacage ) are often heavier and less rustic than with the Middle Ages. they rub on the trunks, eat barks and the thorough ones, trample the substage. The Porc S ( Panage ) consume the one great part of fructifications which they find, the Champignon S undergrounds (Truffe of the stag for example) and trample the Humus. The Mouton S éradiquent the substage, but in fact the Chèvre S make the most damage, being able to destroy the forest settlement by barking the trunks and while going up to the trees. With the Lebanon and the Morocco, the old sylvopastoralime several millenia is regarded as the principal threat of the last Cédraie S. These animals can they play in forest the part that there the large mammals of prehistory played, whereas we made disappear or strongly regress the large predatory ones, It is a question which the scientists put. All is question of balance!

Lastly, the Homo sapiens feels often biologically unsuited to the life in forest, medium which could satisfy only one small portion of the population. The demographic development of humanity returned part of the clearing necessary, therefore justifiable, until a certain time. But nowadays, deforestation less and less has bond with the need for installing populations. Besides one observes a generalized phenomenon of increase in urban populations and reduction in the rural populations.

Consequences

The first consequence of deforestation is the setting in danger of many species, sometimes still unknown, in consequence of the disappearance of their natural habitat, and thus a reduction in the Biodiversité. However, it is advisable to remain careful on the effects of deforestation because the extension of forest surfaces as that of deforestation are not scientifically established and indisputable data.

In South America, in particular with the Brazil, the local populations are threatened by deforestation in their traditional lifestyle.

The wet tropical forests emit very large quantities of oxygen and absorb much CO₂, the scrap organic matters also produce many Méthane (which is also a gas with greenhouse effect). These ecosystem S complexes would require to be preserved and studied better.

The destruction of forest cover involves also an aggravation of the erosion of the grounds and the disappearance of the Humus accumulated.

Deforestation in Brazil along the Amazon causes a fall of the contributions in sediments in this one, which involves the draining of the mangroves in the long term several thousands of kilometers downstream from the river with for consequences:

• the disappearance of a single biodiversity in the world;
• disappearance for the Indians of their incomes because of disappearance of this ecosystem.

On the total warming

The forest biomass stored of 1990 to 2005 approximately 283 Gigatonnes (Gt), but with an on a worldwide scale recorded reduction in 1,1 WP per annum. The sum of carbon stocks of the forest biomass, the deadwood, litter and the ground is approximately the double of carbon present in all the atmosphere.

If the forests account for 40% of the quantity of carbon of the biomass on Earth, it is understood that their degradation can make double the CO rate of the atmosphere. Although the trees absorb up to CO 20% in addition to the fact even of the increase in the atmospheric CO rate, the déforestaiton rejects 1,1 carbon WP each year. The effect on the Climate warming is thus considerable.

See also: Cycle of carbon, Well of carbon, Gas with greenhouse effect, Rejections of CO2

On the local climate

Deforestation causes a modification of the climate on a worldwide scale as well as to the local scales : the trees contribute more than the remainder of the flora to the phenomenon of evapotranspiration and by there of pluviometry; source of a vital local moisture in tropical zone. Their roots décolmatent the grounds and can go to seek water until several tens of meters of depth. They play also the part of wind-cutter and moderate the thermal shocks in the cold zones. Their disappearance is thermohygrometric source of disturbances of the Couple. Lastly, the forest absorb the light into refreshing the air by its evapotranspiration, where the naked ground returns the energy of the sun towards the atmosphere which it heats and dehydrates (Albédo). The average room temperature can locally increase of more than 10 °C after a deforestation in tropical zone. This local warming modifies the atmospheric pressure, which itself influences the displacement of the masses of air and the cells of storms. The pluviometric cycles are thus modified on a worldwide scale, causing dryness and floods in areas which are usually not subjected there.

On the medium and the biodiversity

• Following a cut with white and in particular in tropical zone, the naked left ground undergoes an important scrubbing by the torrential, unutilised and non-braked rains by the vegetation. The Humus disappears quickly and leaves only the rock-mother, unsuitable with the vegetation. The revegetalisation is all the more impossible as the tropical plants are mainly shade-loving (they can push only in the shade which a forest gets).

the Désertification is a problem which currently threatens 900 million people and touches 3,5 billion hectares, that is to say the quarter of the emerged grounds.

• the forests have a role of protection of the grounds which does not exist obviously any more with their disappearance: by retaining the ground, the rocks and snow with their roots, the trees prevent the landslide and the avalanches . Their Humus limit the streaming and erosion and supports the infiltration towards the tablecloths.

This is why the forests known as “of protection” are theoretically untouchable.

• deforestation of course causes the destruction of habitats of thousands of animal species and vegetable , often condemned to disappear. Three species disappear thus each hour, either 72 per day, or 26.280 per annum.

The forest is indeed the medium which shelters the major part of the living beings.

On water

• deforestation unrelentingly involves raw, floods and flow mud devastators: the forests indeed retain the majority of rainwater (ten times more than one pasture) and gradually slacken it by evapotranspiration. They thus maintain the ground water and control the hydrous mode.

With their disappearance, this rainwater (abundant in the tropical countries) streams in torrents to the rivers, thus causing extremely destroying risings. This water which streams carries with it the ground, which is found in the bed and the mouth of the rivers. The Rhone thus lost two meters of depth upstream of Lyon because of the deforestation of the mountain pastures of mountain. The river thus extends its bed, still worsening the floods and causing fatal mud flows, as it was the case in China before they include/understand with their costs the utility of the forests. Deforestation in China thus ceased (it just moved since their wood from now on is imported.)

• the opacification of the water which carts all these muds causes the disappearance of fauna and the flora and involves serious piscicultural problems.

• the water filtered by the alluvial forests is purified: 30 meters of bordering forest retain to it quasi totality of the agricultural Nitrate S. Deforestation further increases the problems of drinking water .

On the Man

• the disappearance of the forest and piscicultural resources causes famines , impossible agriculture being long-term on a ground subjected to the turning into a desert.

• the drynesses, the famines and the absence of drinking water support the dissemination of diseases .
• the economy is dedicated to the failure on the desert created by deforestation.
• deforestation involves social problems like the disappearance of tourism (independent source of incomes in certain countries), the fall of the framework of life (landscape…), the disappearance of cultural heritages related to the forest, and the death of the populations autochtones: at the twentieth century, 90 tribes were eliminated, so much so that some speak about genocide.
• And finally loss of a priceless medical device for science: 70% of the useful plants against cancer for example are only in the wet tropical forests. More than one quarter of the drugs prescribed in the U.S.A. are derived from plants of the tropical forests.

In the same way, a whole potential of food and products unknown or unutilised are lost.

Possible solutions

By each individual

• to use wood by avoiding the abusive threatened gasoline consumption, there exist various means:

1. Wood éco-certified: exotic wood profiting from a éco-certification (PEFC, FSC…) guarantee a source of forests whose resource is managed in a durable way. The boycott of the not threatened exotic wood could slow down the development of the countries concerned and paradoxically cause an opposite effect: the forest, become nonprofitable, would be cleared and placed at the disposal of agriculture.

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