Boasting a number eight times higher than the last best estimate, a new assessment estimates that there are approximately three trillion trees on Earth. The previous estimate was around 400 billion at most.
The assessment was produced by Dr. Thomas Crowther of Yale University, and his colleagues, BBC reports. The team used a combination of ground field data and satellite imagery to find the new number. The new total represents approximately 420 trees for every person on Earth.
This new number will be used as a baseline for a wide range of research topics, such as animal habitats, and climate models.
Dr. Crowther says to BBC that it is not that they have discovered a ton of new trees. “It is not good news for the world or bad news that we have produced this new number.”
Crowther goes on to explain that the number describes the state of the global forests in numbers that can be understood and used by scientists and policymakers alike.
The greater use of ground data was a contributing factor to the larger number. Dr. Crowther’s team collected data from 400,000 forest plots, worldwide. In doing so, the team included areas that were not previously hand counted the density of trees in a forest area. This allowed the team to create better models than ones that utilized satellite images, which give a good idea of forest coverage, but not of what lies below the canopy.
The estimate does make the human influence on deforestation very clear. An estimate by the team states that 15 billion trees are removed a year, with only five billion being planted back.
The way tree density is measured leaves a lot of room for error. Dr. Martin Lukac of University of Reading says to BBC, “The previous estimate of trees in the world was 400 billion. The new estimate is three trillion large trees. There are so many margins of error in this study that the real number could be anything between the two – or even 10 times higher.”