The amount and type of forest cover has changed over time, both for natural and man-made reasons.
In which way are people affecting forest ecosystems and are there any signs of recovery?
Causes of deforestation
Forests cover over 30% of the land area on our planet. As covered in our Quick Guide: The Basi(c)s, they provide us with numerous goods and services such as food, fuel wood, timber and freshwater. However, every year we lose 3.3 million ha of forest, which jeopardizes these benefits and impacts our livelihoods.
What are the main causes of deforestation?
The main driver of deforestation is agriculture. As the demand for soy and palm oil rises, forests are cleared and converted to plantations. Large-scale commercial agriculture accounts for about 40% of deforestation in the tropics and subtropics during the period 2000—2010, and it is especially important in Latin America and Asia.
Small-scale agriculture was responsible for 33% of deforestation in the tropics and subtropics during the period 2000—2010 and especially important in Africa. Small-scale farmers often clear forests by cutting down and burning trees (slash and burn agriculture) to grow their own food.
Another cause of deforestation, especially in Latin America, is the forest conversion to pastures for cattle ranching. In Argentina, pasture expansion accounted for 45 percent of forest loss in 1990–2005.
Although forest plantations are increasingly more common, the demand for timber, paper and derivative products is still very high. Illegal logging accounts for 15-30% of all wood traded globally and illegally harvested wood is sold in USA and Europe.
Around the world many people (need to) harvest wood to use it as fuel for cooking and heating. Fuel wood harvesting is sometimes illegal, but it does not necessarily lead to deforestation and is more often associated to forest degradation.
Forests are also threatened by mining operations. In the Amazon rainforest, more and more small- and large-scale operators are mining alluvial gold deposits, clearing forests and releasing mercury into the rivers and polluting them. In the Congo Basin, mineral extraction has increased in the last 15 years, and forests have been cleared to establish artisanal and open-pit mines.
Other drivers of deforestation include urban expansion and infrastructure. Between 2000-2010, urban expansion was responsible for 10% of deforestation in tropical and subtropical areas. Over the coming decades, urban populations are projected to grow, especially in Africa and Asia, which will contribute to additional forest loss. Infrastructure for transportation and energy is vital for the development of any country. However, the expansion of road networks and the construction of hydro-electrical dams in Latin America and Asia has increased deforestation.
Wildfires are becoming more common around the globe, from Siberia to Chile. In Europe, for example, forest fires burnt over 700,000 hectares of land in 2017. Nearly all wildfires were man-made but climate change (hot and dry conditions) and poor land management practices (overgrown vegetation and planting of flammable species, like Eucalyptus) were contributing factors.
References:
FAO (2016) – The State of the World’s Forests. Food and Agriculture Organization of the United Nations. Rome, 2016. Available online at http://www.fao.org/3/a-i5588e.pdf
Deforestation – how much has changed?
During the last seventy years, the remaining forests in our planet have been lost at a speed and scale not seen since men began to use them. After the destruction of most of the temperate forests in Eurasia and North America during the previous centuries, the impact has shifted to tropical and sub-tropical areas (1).
A growing human population and the need for land and forest resources have kept the pressure on ecosystems at a high level in different ways, often without concern for the short and mid-term consequences. Around the globe, huge areas have changed in a dramatic and fast way due to urban expansion, large-scale wood extraction (legal or not) and clearing for plantations and cattle-raising. At the same time, the livelihoods of many people in poorer regions still rely on using natural resources in a destructive way, leaving the future of the remaining old forests in great danger if no changes are made. Cooking with wood remains the only alternative for many, with a single family needing 1 to 3 t of firewood every year. Indiscriminate collection of firewood, clearing forests for farming plots and grazing aggravates soil erosion, reduces available water and the sustaining capacity of the habitat. This leads to increased hardship, preventing people from building past survival strategies and short-term perspectives.
On a positive note, the rate of deforestation has slowed down in the last decade. Some areas, particularly in the northern hemisphere, have had gains or are being managed and restored in a positive way (2). Still, the areas destroyed every year remain large and the net global result negative (3).
Many of the benefits provided by forests – also called ecosystem services – have a great direct value for society: protected soil is less prone to erosion and has increased water retention; waterways are kept clean of excessive sediments, reducing the effect of floods; air quality is improved by not having particles and pollutants dispersed by the wind; fertile soil is retained and protected; drastic variations in temperature and rain cycles are partially regulated at a local level, reducing the swings between floods and droughts. Mature or intact forests have a greater capacity than newly-planted forests to perform these functions and are often more resilient.
Keeping healthy, mature forests reduces economic losses and threats to livelihoods, helping to mitigate social conflicts due to the lack of resources and the displacement of people. It also ensures an habitat for many other species and provides a source of beauty and inspiration for people. Finally, restoring forests to their condition 70years ago would capture huge amounts of CO2, just by growing trees, reducing the need for costly single-purpose solutions for fighting climate change risks.
References:
(1) Taken from FAO (2012) – The State of the World’s Forests. Food and Agriculture Organization of the United Nations. Rome, 2012. Available online at http://www.fao.org/3/a-i3010e.pdf.
(2) See charts compiled from different sources and presented here: https://ourworldindata.org/forest-cover/#global-forest-cover-change-over-the-last-centuries
(3) See also (2) and satellite images compiled by the Global Forest Change, available online at https://earthenginepartners.appspot.com/science-2013-global-forest
