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Updated Sep 4, 2015

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New stats are tree-mendous

A new assessment produced by Yale University has claimed that there are just over three trillion trees on Earth. Previous estimates counted 400 billion trees at most, making the new estimate eight times as big!

The team from Yale University combined a mass of ground survey data with satellite pictures to produce the new assessment. The new data could also form a new baseline for research projects, including in relation to the climate given that trees play a big part in removing carbon dioxide from the atmosphere.

However, Dr Thomas Crowther of Yale University warned that although the estimate is much higher than in the past, it does not mean that anything changes. "It's not like we've discovered a load of new trees; it's not like we've discovered a load of new carbon. So, it's not good news for the world or bad news that we've produced this new number. We're simply describing the state of the global forest system in numbers that people can understand and that scientists can use, and that environmental practitioners or policymakers can understand and use.

The team also estimates that humans are removing approximately 15 billion trees a year, of which only around five billion are being replanted.

Co-author of the research, Dr Henry Glick, said: "The net loss is about a third of a percent of the current number of trees globally." He added: "That doesn't seem to be an insignificant portion and should probably give us cause for considering the role that deforestation is playing in changing ecosystems. And where tree losses are often tied to timber supplies and land-use conversion for agriculture, as the global human population grows, we may see the net loss increase as well."

Dr Martin Lukac from the University of Reading warned that there were so many margins of error in the study that the true number of trees could be very different.


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