The forests carry out a fundamental
roll in the protection and evolution of grounds.
In addition, they constitute an important factor
of climatic control.
Through the centuries it had accumulated tests about how
the human intervention can produce innumerable Earth damages.
One of the forms that that intervention assumes, the deforestation,
has seriously affected the forests of the planet. About 10,000
years ago - before the beginning of agriculture - that type
of biome extended on about 4,200 million hectares, the two
third parts of the terrestrial surface. Today, in extensive
regions of Asia, Europe and North America the natural forests
had disappear, and the deforestation threatens to one of the
most extensive forest, the amazonian.
The deforestation, which consists on the destruction of forests
by burning or cutting them, goes accompanied by the technological
progress, that creates new and more serious problems as well.
The fire and the necessity to qualify the ground for agriculture
and the pasturing, devastate great forest spaces, but in the
long term the grounds are eroded and impoverished by the absence
of protective natural vegetation.
In America there were great wooded extensions to the arrival
of the Spaniards. The action of more and more destructive
technologies, did that at the present time only one small
part of the territory is covered by forests. The rest was
destroyed to obtain firewood and wood of construction and
for the manufacture of furniture, or simply burned to disassemble
the grounds that could be used in the agricultural production.
That way, complete populations of certain species were considerably
reduced.
Other trees served like fuel in furnaces
of mineral smelting. The quebracho of Chaco were destroyed
to take advantage of the tannin, substance used in the leather
tanning. At the beginning of the XX century the south zone
of this region began to change its wooded appearance, to become
a barren and depopulated place.
In these times, the most serious danger is
the one than threatens the Amazonia. This jungle region, bathed
by the Amazon river and its affluents, counts on a river basin
of more than seven million of km2, in territories of Brazil,
Peru, Bolivia, Colombia, Ecuador and the Guayanas.
From the irruption of the European colonizers
to 1970, 0.5% of the amazonian forest had been deforested;
from that year to 1991 it was arrived at 10% (about 700,000
km2). The grounds are destined, in general, to the farming
operation or the petroleum search and the extraction of minerals,
and also the future construction of the great transamazonian
highway, of 3,000 km in length. It is predicted that for year
2020, 78 dams will have been raised, that will flood 100,000
km2 of this territory.
In this true lung of the planet 80,000 vegetal
species coexist; 30,000 animals: 50% of the biodiversity (number
of species that lives in a certain region) which has the Earth.
Many of those forms of life are in serious danger now, by
the increasing destruction of their habitats.
The destinies that occur to the
wood extract of a forest are innumerable: from its
use like firewood to hulls, pipes or musical instruments
that, for their manufacture, require certain species.
The deforestation creates new deserts
The presence of the forest determines a constant
interchange of dioxide of carbon and oxygen between the alive
organisms and the atmosphere. The plants consume carbon dioxide
and release oxygen; when they die, it happens the opposite.
The disappearance of forests, on the other
hand, affects the cycle of water, which is a necessary factor
of balance of the climate and the atmospheric changes.
The deforestation modifies the processes
of evaporation and the rain regime, with immediate climatic
changes that affects the possibilities of survival of great
amount of species, in appearance not damaged in direct form.
13,500 Km2 of tropical forest are annually
burn, to transform the land into farming or pasturing areas,
taking to the desertification. It is called thus to the process
by which a territory that did not have the climatic characteristics
of the natural deserts finishes acquiring them, because of
the destruction of its vegetal cover.
As a result of it, the grounds become impoverished
and the smallest particles fly by the wind, or slip with rains.
The fertile and productive ground, that needs hundreds of
years to form, is also unstable.
In order to maintain the cohesion and firmness
of his particles, it requires especially of the plants and
their roots. And if the plants are destroyed, the erosion
due to the water and the wind soon leaves the open the rock
that, only after the passage of many years, will be able to
return to be taken advantage of by vegetables.
In sum, as much agriculture as the ways,
the dams and the slumses are necessary; and in new territories,
they cannot be done without deforesting. But the elimination
of arboreal species does not have to exceed certain limits;
if rational plans of reforestation do not exist, that intervention
on the ecosystem will have serious consequences for the food
web and life in general.
The specialized
breeding grounds provide with small trees as much to the
forest activity like a the forestation areas that the
governments establish to avoid the disappearance of the
forests.
