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By Mercedes Arancibia
This is the calculation made by a team of 38 scientists from the American University of Yale (Connecticut. Each year, forests lose 10 billion trees despite reforestation work, reports the digital page of the international news channel France 24.
For the authors of the article, there are actually ten times more trees than previously thought, although their disappearance "increases in free fall": "The previous estimate, based on images taken by satellite, established the figure of 400,000 million trees ”. 43% of the trees belong to tropical and subtropical forests. The ratio per inhabitant of the planet is 422 trees / person. 15 billion trees are cut down annually, particularly in tropical areas. Scientists add that since the beginning of agriculture, about 12,000 years ago, the number of trees on earth has decreased by between 46% and 50%.
"We have almost halved the number of trees on the planet, which has affected the climate and health - says Thomas Crowthe, director of the team that carried out the research - The study highlights the extent to which more efforts are necessary if we want to restore healthy forests around the world ”.
To accurately count, Crowther's team has used satellite data combined with 429,775 calculations made on the ground in more than 50 countries. The environmental characteristics of the regions (temperature, elevation of the terrain) have allowed him to complete the estimates; for regions where no calculations have been made, they have used density trends in similar regions.
Forests are generally considered to be the lungs of the earth and play an important role in climate change. The main predators of trees are the large territories of arable fields, the wood market and the toilet paper market.
"The phenomenon of deforestation - say the authors of the article - has been known for a long time and the fact that we count almost exactly the number of trees does not change much" because, in addition, "if we want to know the environmental balance of deforestation You don't have to think about the number of disappeared trees, but rather about carbon units ”. One hundred-year-old tree can contain more carbon dioxide than ten young specimens; so the destruction of the former will have a greater impact on the climate.