Climate Change
Besides other measures, such as the production of renewable energies or the expansion of public transport, planting trees is an effective method to combat man-made climate change.
A study conducted by ETH Zurich has shown that with a global afforestation of 9 million square kilometers, which roughly correspond to the surface of Brazil, two-thirds of man-made CO2 emissions can be compensated.
It is estimated that trees can sequestrate about 10kg of CO2 per year on average. Exact figures exist for the South American tropics: a tree is able to absorb on average approximately 16 kg of CO2 per year in the first 20 years.
Biodiversity
Forests cover almost a third of the earth’s land area. They are the most species-rich habitats in the world. Of 1.3 million known animal and plant species, about two-thirds live in forests.
Tropical rainforests are of particular importance. Despite the fact that they cover only 7% of the earth’s surface, they are home to 50% of all animal and plant species worldwide. Their trees store twice as much carbon as trees outside the tropics.
Social Benefits
Forests are habitats and provide livelihoods for 1.6 billion people, including many indigenous peoples. Furthermore, they offer protection against erosion, avalanches and floods and regulate the water balance as natural water reservoirs. One third of the world’s largest cities get a significant part of their drinking water from forest reserves.
Forests store about half of the carbon sequestered on Earth. They are able to bind 20 to 50 times more carbon than other ecosystems.