The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization.
What does it mean? In absolute terms, a surprise. But as we have nevertheless chopped down an awful lot of them, it means we have more to do to restore what has been lost. The Washington Post reports that deforestation is still a major, accelerating problem.
The new research suggests that massively more trees need to be planted than previously thought — but Crowther said he thinks that will only inspire activists to redouble their efforts.
The study shows that trees are most prevalent in the tropics and subtropics – home to 1.39 trillion trees – but that boreal or northern forests contain another .74 trillion, and temperate forests contain .61 trillion. It also suggests, rather surprisingly, that boreal and tundra forests often have a greater tree density than tropical ones.
The photo here is by Beth Moon, a portrait of one of the oldest known trees.