For example, countries build roads into remote areas to improve overland transportation of goods. The road development itself causes a limited amount of deforestation. But roads also provide entry to previously inaccessible—and often unclaimed—land. Logging, both legal and illegal, often follows road expansion and in some cases is the reason for the road expansion. The roads and the logged areas become a magnet for settlers—farmers and ranchers who slash and burn the remaining forest for cropland or cattle pasture, completing the deforestation chain that began with road building.
In other cases, forests that have been degraded by logging become fire-prone and are eventually deforested by repeated accidental fires from adjacent farms or pastures. Although subsistence activities have dominated agriculture-driven deforestation in the tropics to date, large-scale commercial activities are playing an increasingly significant role.
In the Amazon, industrial-scale cattle ranching and soybean production for world markets are increasingly important causes of deforestation, and in Indonesia, the conversion of tropical forest to commercial palm tree plantations to produce bio-fuels for export is a major cause of deforestation on Borneo and Sumatra.
In densely populated central Africa, small subsistence plots cover the once-forested hillsides. Although poverty is often cited as the underlying cause of tropical deforestation, analyses of multiple scientific studies indicate that that explanation is an oversimplification. Poverty does drive people to migrate to forest frontiers, where they engage in slash and burn forest clearing for subsistence.
But rarely does one factor alone bear the sole responsibility for tropical deforestation. State policies to encourage economic development, such as road and railway expansion projects, have caused significant, unintentional deforestation in the Amazon and Central America.
Tropical forests are increasingly destroyed by land-seeking rural poor. There are more than million rural poor in the world without land or secure access to it, including some 85 percent of the households in Java and 70 percent in Brazil.
Usually the poor migrate on their own; occasionally they are sponsored by government projects. Access roads into forest areas - aiding timber, mineral and oil extraction - frequently lead to spontaneous agricultural and livestock development. The colonists move on after only two or three years as cleared areas are plagued by weeds, insects, and declining fertility. The land is often bought by cattle ranchers. Within 5 to 10 years, soil fertility continues to decline, pastures are invaded by weeds and the areas are abandoned.
The effect is a moving frontier that results in waste and destruction. The current Brazilian estimate is that. And our estimate would be that approximately 95 percent of all the land in the tropics that can be put into sustainable agriculture is already in cultivation. Yet, colonization, funded both by national governments and international lending institutions, continues.
Industrial wood accounts for 20 percent of the total volume removed from tropical forests, but only a third is exported. While logging may not account for most global deforestation, in certain areas, it is the principal cause. Seventy percent of all tropical hardwood imports go to Japan; the Japanese consume more wood per capita than any other people on earth.
Between and Southeast Asia increased exports of tropical hardwoods 24 times. In the same period, developed nations increased all tropical hardwood imports from 4. Imports are expected to be 95 million cubic meters by the year The process of industrial logging is highly selective, with only a few species and trees of a certain size harvested.
Of the thousands of trees in the Amazon basin, some with proven value, only about 50 species are harvested. Africa exports about 35 species, but 10 account for 70 percent of all exports. In Southeast Asia, logging of some species occurs, but only a dozen or so account for most exports. Often less than five percent of the total number of trees are harvested in any area. Yet, logging operations can leave 30 to 65 percent of the residual trees damaged beyond recovery even minor injuries allow pathogens to kill trees.
Logging operations and roads - sometimes 10 km for each square kilometer of forest exploited - destroy 10 to 30 percent of the forest area. Roads often allow colonists to complete the deforestation process. New harvesting techniques, including whole tree harvesting, the use of hundreds of species, and on-site chipping, make clear cutting more common.
This allows for to percent greater yields per area. However, clear-cut forests do not regenerate easily if the area is too great or if it is not allowed to regrow immediately.
From , world consumption of paper products increased from 40 to million tons. Today, developed countries use million tons of pulp a year, the developing world a little over 20 million. In the former, per capita consumption is more than kg of paper products per year kg in the U.
Deforestation can result in more carbon dioxide being released into the atmosphere. That is because trees take in carbon dioxide from the air for photosynthesis , and carbon is locked chemically in their wood. When trees are burned, this carbon returns to the atmosphere as carbon dioxide. With fewer trees around to take in the carbon dioxide, this greenhouse gas accumulates in the atmosphere and accelerates global warming. Tropical forests are home to great numbers of animal and plant species.
When forests are logged or burned, it can drive many of those species into extinction. Some scientists say we are already in the midst of a mass-extinction episode. More immediately, the loss of trees from a forest can leave soil more prone to erosion. This causes the remaining plants to become more vulnerable to fire as the forest shifts from being a closed, moist environment to an open, dry one. While deforestation can be permanent, this is not always the case.
In North America, for example, forests in many areas are returning thanks to conservation efforts. Carbon dioxide is also the byproduct of burning fossil fuels. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
The Rights Holder for media is the person or group credited. Tyson Brown, National Geographic Society. The natural world is complex, interconnected, and made of thousands of inter-dependencies and among other functions, trees provide shade and colder temperatures for animals and smaller trees or vegetation which may not survive with the heat of direct sunlight.
Besides, trees also feeding animals with their fruits while providing them with food and shelter they need to survive.
Then you should find out some examples of how Life is interconnected:. Healthy forests support the livelihoods of 1. This means there are many people depending on forests for survival and using them to hunt and gather raw products for their small-scale agriculture processes. But in developing countries such as Borneo, Indonesia, Vietnam, Brazil, or Mexico, land tenure systems are weak.
Locals then have to make one of two choices. Or they can stay and work for the companies exploring it in remote plantations — often getting unfair wages and working under inhumane conditions. Related: Is Avocado Production Sustainable? In the long term, the lack of healthy, nutritious soil can lead to low yields and food insecurity. Deforestation weakens and degrades the soi l. Forested soils are usually not only richer on organic matter, but also more resistant to erosion, bad weather, and extreme weather events.
This happens mainly because roots help fix trees in the ground and the sun-blocking tree cover helps the soil to slowly dry out.
As a result, deforestation will probably mean the soil will become increasingly fragile, leaving the area more vulnerable to natural disasters such as landslides and floods. Deforestation also has a very strong contribution to climate change.
If we speak about tropical forests, they hold more than gigatons of carbon, according to WWF. Both these effects negatively contribute to the greenhouse effect and to climate change. To understand the challenges of deforestation, check this National Geographic video. Around the world, deforestation occurs mostly in the tropics where there are different types of forests are: from wet and hot rainforests to others that lose their leaves in the dry season and become woodlands.
Some parts of the world have managed to protect their forests from deforestation while others have seen their forestal area decline. These changes significantly differ but there are 3 important worldwide examples of deforestation: the Amazon rainforest, Indonesia and Borneo, and Africa.
Brazil and the Amazon forest are also important for the wrong reasons deforestation areas worldwide. Before , large industrial projects such as dams, roads, or mines were the main causes of deforestation in the Amazon region, together with subsistence farming.
However, for around thirty years, the causes of deforestation in the Amazon rainforest are changing. The development of intensive livestock production, combined with meat consumption increases in developed countries, is thus the main cause of deforestation in the Amazon forest. Indonesia and the island of Borneo are emblematic symbols of the global phenomenon of deforestation.
This region in Southeast Asia is naturally one of the richest reserves of forest and biodiversity in the world. But at the same time, it is also one of the regions that have been suffering the most deforestation in recent decades. According to FAO , between and alone, Indonesia lost about 9 million hectares of its forests, largely due to deforestation caused by palm oil.
One of the most important causes of deforestation in Indonesia and Borneo is unquestionably the production of palm oil. According to FAO, between and , nearly 6 million hectares of palm oil plantations have gradually replaced Indonesian forests. This makes the palm oil industry one of the biggest contributors to deforestation in Southeast Asia — and it is expected to continue to be so.
Certifications are starting to appear, including sustainable palm oil labels that aim to prove it comes from certified forests and workers are fairly paid like RSPO.
Despite industries still posing serious environmental problems, the media spotlight on this topic is beginning to shift the lines.
0コメント