The new estimate includes “ground truth” density data from 400,000 forest plots 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. […]