Earth’s Trees Number Three Trillion

Local Editor

There are just over three trillion trees on Earth, according to a new assessment.

The figure is eight times as big as the previous best estimate, which counted perhaps 400 billion at most.

It has been produced by Thomas Crowther from Yale University, and colleagues, who combined a mass of ground survey data with satellite pictures.

The team tells the journal Nature that the new total represents upwards of 420 trees for every person on the planet.

The more refined number will now form a baseline for a wide range of research applications - everything from studies that consider animal and plant habitats for biodiversity reasons, to new models of the climate, because it is trees of course that play an important role in removing the greenhouse gas carbon dioxide from the atmosphere.

Key to the new estimate is the greater use of ground-truth data. The team collected tree density information from over 400,000 forest plots around the world.

This included many national forest inventories and a host of peer-reviewed studies where workers had actually gone out and counted the number of trunks in a given area and in a given forest type.

This then enabled the research team to build a model that better characterized what they were seeing in satellite pictures, which are very good at showing forest extent but are not so good at revealing just how many individual trees are standing below the canopy.

Accordingly, Dr. Crowther indicated that "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".

Source: News Agencies, Edited by website team