May 15, 2017 - By Patrick Monagan - Science Magazine  / Forest Business Network
The Age of Exploration may be long past, but even in the 21st century, our maps can still get a major update. Using satellite imagery, a new study has found hidden forests all over the world—almost enough for a second Amazon—in areas with little moisture known as drylands. Past estimates of how much of the world’s drylands are covered in forests have run into lots of problems: For instance, the satellite images used to measure them are often so low-resolution that it’s hard to figure out the difference between a tree, a shadow, or even a patch of dirt. To correct for that, an international team of researchers performed the first global study using a new set of ultra–high-resolution Google Earth images—in which each pixel represents a patch of ground less than a meter wide, as opposed to tens of meters. Hundreds of scientists and students then combed through 210,000 images and found that the world’s drylands host 40% more forests than thought, the team writes today in Science. That’s more than a 9% bump in total global forest coverage, or two-thirds the size of the Amazon.