Causes of deforestation
Forests cover around 30% of the land's surface according to NASA but they are under threat from a variety of human activities. This is remarkably short-sighted given the many benefits forests bequeth mankind: clean air, timber, shelter, soil stability, climate regulation, biodiversity and food supply. Data on deforestation rates is variable. A recent report by the United Nations Food and Agriculture Organisation (UNFAO) estimated that around 7.3 million hectares are being lost a year (18 million acres). Other reports claim that between 1960 and 1990, 20% of the world's tropical rainforests were wiped out whilst other reports claim that tropical rainforests will be all but wiped out by the middle of this century.
Deforestation caused by fires
Fires are a natural and beneficial element of many forest landscapes, but they are problematic when they occur in the wrong place, at the wrong frequency or at the wrong severity.
Each year, millions of acres of forest around the world are destroyed or degraded by fire. The same amount is lost to logging and agriculture combined.
Fire is often used as a way to clear land for other uses such as planting crops.
These fires not only alter the structure and composition of forests, but they can open up forests to invasive species, threaten biological diversity, alter water cycles and soil fertility, and destroy the livelihoods of the people who live in and around the forests.
Deforestation caused by clear-cutting for agriculture
The biggest driver of deforestation is agriculture.
According to the United Nations Framework Convention on Climate Change (UNFCCC) secretariat, the overwhelming direct cause of deforestation is agriculture.
Subsistence farming is responsible for 48% of deforestation; commercial agriculture is responsible for 32%.
Farmers cut forests to provide more room for planting crops.
Often, small farmers will clear a few acres by cutting down trees and burning them in a process known as 'slash and burn' agriculture.
Deforestation caused by ranching
Cattle ranching is now the biggest cause of deforestation in the Amazon, and nearly 80 per cent of deforested areas in Brazil are now used for pasture.
The cattle industry has ballooned since the 1970s, giving Brazil the largest commercial cattle herd in the world.
Since 2003, the country has also topped the world's beef export charts and the government plans to double its share of the market by 2018.
The impact this is having on the forest is huge - between 1996 and 2006, an area the size of Portugal was carved out for cattle ranching. As with the soya industry, a host of social ills have followed the wave of expansion. Cattle ranching has the highest rates of slave labour in Brazil .
Deforestation caused by unsustainable or illegal logging
According to the United Nations Framework Convention on Climate Change (UNFCCC) secretariat, logging is responsible for around 14% of deforestation activity.
National laws supposedly regulate the production and trade of timber products at all stages, from harvesting to processing to sales. These laws can be violated in any number of ways, such as taking wood from protected areas, harvesting more than is permitted and harvesting protected species.
Illegal logging occurs around the world, and in some places, illegal logging is more common than the legal variety.
This destruction threatens some of the world’s most famous and valuable forests, including rainforests in the Amazon, Congo Basin, Indonesia and the forests of the Russian Far East.
Illegal logging also depresses the price of timber worldwide, disadvantaging law-abiding companies, and depriving governments of revenues normally generated by duties and taxes.
Poor communities near forests are often vulnerable when outsiders try to gain control over the timber nearby, which can lead to repression and human rights violations.
Deforestation and climate change
Forests and climate are intrinsically linked: forest loss and degradation is both a cause and an effect of our changing climate.
It is likely that changing temperature and precipitation patterns will produce a strong direct impact on both natural and modified forests. Studies and simulations predict a polar-ward movement in forest ranges but exact impacts can only be guestimated and show a high degree of regional variability. Some species will thrive, others decline markedly.
Fires, insects, pathogens, and extreme events will all be affected by changes in climate.
For forestry, the climate change-induced modifications of frequency and intensity of forest wildfires, outbreaks of insects and pathogens, and extreme events such as high winds, may be more important than the direct impact of higher temperatures and elevated atmospheric carbon dioxide levels.
Although models suggest that global timber productivity will likely increase with climate change, regional production will exhibit large variability.
Climate change will also substantially impact other services, such as seed availability, nuts, berries, hunting, resins, and plants used in pharmaceutical and botanical medicine. In summary, a warming climate will have positive and negative impacts.
Deforestation cause by human overpopulation
As the human population continues to grow, there is an obvious need for more food. Wood is still a popular fuel choice for cooking and heating around the world, and about half of the illegal removal of timber from forests is thought to be for use as fuelwood.
In addition, agricultural products, such as soy and palm oil, are used in an ever-increasing list of products, from animal feed to lipstick and biofuels.
The major increase in soybean cultivation is a direct response to growing (population) demand. Soybean meal is the largest source of protein feed in the world, and is
generally used in animal feed.
To grow soybeans, vast expanses of land are needed. Production is overtaking huge areas in fragile ecosystems such as the:
Brazilian Cerrado (a relatively flat, mixed woodland and savannah area of central Brazil)
and the Atlantic Forests of South America.
Rising demand has created incentives to convert forests to farmland and pasture land. Once a forest is lost to agriculture, it is usually gone forever—along with many of the plants and animals that once lived there.