Very interesting research has been published in Nature magazine. Researchers created the most detailed map of forests around the world. All the previous attempts to estimate the number have been done based on satellite images. The number of trees around the world was estimated at the level of 400 billion. Although remote imaging reveals a lot about where forests are, it doesn’t give an answer to how dense the forest is.
This time researches decided to take a dual approach. They gathered data from various existing ground-based counts of trees covering about 430,000 hectares around the world. These counts allowed them to improve tree-density estimates from satellite imagery. Then the researchers applied those density estimates to areas that lack of high quality ground data.
With this approach researchers calculated that the actual number of trees around the world is at the level of 3 trillion, so 8 times higher than previously counted. The result of this research has been published in the form of the density map.