Understanding the Science
19th Century Lumberjacks of California. Copyright Humboldt State University.
As mentioned on our homepage, planetary tree counting is physically impossible. Thanks to modern technology like satellite imagery and large area surveying, scientists are gaining a clearer sense of our impact on nature. Unfortunately, the most optimistic figures are alarming. Even with approximations, if we were to round up or down in the favor of the environment, nature is still losing by huge margins. If we acknowledge fundamentals like the difference between old growth (see the 2,000-year-old redwoods above) to the relatively dwarfed tree stands of today's forests, we must recognize we're not comparing the same thing in history. This means we must consider the correlation of a tree's age to the environmental contribution it can make on our planet. One tree is not equal to one tree. A ten-year-old cedar is inconsequential next to a 500-year-old sequoia. Therefore, we now find ourselves without the luxury to underestimate these numbers, even with significant differentials.
There are around 3 trillion trees on earth
This is according to a global tree density study titled Mapping Tree Density at a Global Scale performed by more than 40 scientists and published in the journal, Nature.
Approximately 15 billion trees are cut down each year
The aforementioned Mapping Tree Density at a Global Scale looked at regression patterns against normal conditions to determine deforestation & consumption caused by civilization.
About 2-4 billion trees are replaced each year
This figure is very approximate. There has not been an exhaustive study on the topic. Figures have emerged from nursery cooperatives and other industry trade groups.
This creates a deficit of about 11 billion per year
15 Billion cut down minus 4 billion planted. 4 billion being rounded up. Therefore, the annual deficit may be much higher.
There are approximately 7 billion people on earth
The human species tree debt is roughly 3 trillion
This is also derived from the Mapping Tree Density at a Global Scale study referenced above. Scientists looked at human civilization patterns against natural conditions to approximate the difference affected by our species.
This comes out to 1 tree per person, per year
This is rounded down considerably and will still be extraordinarily difficult to achieve. The actual tree deficit per person, per year, is 1.57.