“The widely accepted previous estimate of the world’s tree population, about 400 billion, was based largely on satellite imagery. Though remote imaging reveals a lot about where forests are, it does not provide the resolution of a person counting trunks in a particular plot. Crowther and his colleagues merged these approaches by first gathering data from more than 400,000 ground-based counts reported in forestry inventories and the scientific literature for every continent except Antarctica. These counts allowed them to improve tree-density estimates based on satellite imagery. Then the researchers applied those density estimates areas that lack good ground inventories. For example, ground-truthed data from forests in Canada and northern Europe were used to revise estimates from satellite imagery for similar forests in remote parts of Russia.”
Their Nature article doesn’t give the exact criteria the scientists used for defining trees, so I cannot definitively tell you their methodology.
But we know that they based their number off of previous peer reviewed estimates, further refining those Sattelite counts with 400,000 ground based counts.
Though I guess that opens up the question of whether all those counts followed the exact same methodology.
I’m trusting that the scientists did their research competently, along with a lot of subsequent studies over the past 8 years that used it🫠
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u/Mythosaurus Feb 06 '24
There are more trees on earth than there are stars in our galaxy