There are more trees on Earth than stars in the galaxy
A 2015 census estimated about three trillion trees on Earth. The Milky Way contains on the order of one to four hundred billion stars.
Strong2 min read
Crowther and colleagues combined ground plots with satellite data and estimated 3.04 trillion trees, and also estimated that human land use has cut the number by nearly half since the start of agriculture. The uncertainty is real and the number is still in the trillions.
The Milky Way's stellar mass corresponds to something like 10^11 stars, a few times that at the outside. Three trillion is several times a few hundred billion. The comparison reverses if you swap in all the stars in the observable universe, which is the version of the sentence people sometimes reach for and the version that is false.
Caveats
- Both figures are estimates. The tree count in particular is a model, not a headcount.
- The claim is trees versus stars in our galaxy, not versus stars in the universe.
Sources
- 1Crowther T. W. et al.. Mapping tree density at a global scale. Nature 525, 2015.