US: A new study, published in Nature, estimates the number at somewhere around 3.04 trillion i.e. 400 trees per person. Previous estimates had put this number at 400.25 billion, but the new study not only incorporates satellite imagery and it also relies on ground-based measurements of tree density, where a physical person counted the number of trees in a given area.
Every year we are losing 10 billion trees i.e. 1.4 trees per person per year. The new data will help us understand where all the endangered species might be able to live and how much carbon dioxide is being absorbed from the atmosphere. This new data will also help us achieve our target of restoring natural habitats and planting trees.