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Global Count Reaches 3 Trillion Trees
Sep 24, 2015

According to a tally by an international team of scientists there are roughly 3 trillion trees on Earth—more than seven times the number previously estimated.

Key Findings

  • The study also finds that human activity is detrimental to tree abundance worldwide.

  • Around 15 billion trees are cut down each year since the beginning of agriculture about 12,000 years ago.

  • The number of trees worldwide has dropped by 46%.

  • The previously accepted estimate of the world’s tree population, about 400 billion, was based mostly on satellite imagery.

  • Although remote imaging reveals a lot about where forests are, it does not provide the same level of resolution that a person counting trunks would achieve.

  • Scientists merged these approaches by first gathering data for every continent except Antarctica from various existing ground-based counts covering about 430,000 hectares.

  • These counts allowed them to improve tree-density estimates from satellite imagery.

  • Then the researchers applied those density estimates to areas that lack good ground inventories. For example, survey data from forests in Canada and northern Europe were used to revise estimates from satellite imagery for similar forests in remote parts of Russia.

  • The highest tree densities, calculated in stems per hectare, were found in the boreal forests of North America, Scandinavia and Russia.

  • These forests are typically tightly packed with skinny conifers and hold roughly 750 billion trees, 24% of the global total.

  • Tropical and subtropical forests, with the greatest area of forested land, are home to 1.3 trillion trees, or 43% of the total.

Forests are important to humans, not just for their products, but also for their ability to foster biodiversity, store carbon, preserve water quality, and perform other ecosystem services. Up to 45% of the carbon stored on land may be tied up in forests.


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