Earth hosts an estimated three trillion trees, a number that exceeds common estimates for the number of stars in the Milky Way, making our planet remarkably green compared with the stellar population of our galaxy.
The numbers explained
Scientists have combined ground surveys, satellite imagery and statistical models to produce global tree‑density maps that suggest roughly three trillion individual trees on Earth; by comparison, typical estimates for stars in the Milky Way range from about one hundred billion to a few hundred billion, so tree counts surpass stellar counts by an order of magnitude.
How researchers count trees
Estimating global tree totals relies on sampling plots, national forest inventories and high‑resolution remote sensing; models scale up observed densities by habitat and climate zones to produce continuous maps, then sum those densities to reach a global figure that reflects both dense forests and sparsely treed regions.
Why the comparison matters
The comparison between trees and stars is a striking way to appreciate Earth’s biological abundance and to remind people that planetary life, ecosystems and carbon storage are vast and consequential, with each tree playing a role in climate regulation, biodiversity and human livelihoods.
Uncertainty and change over time
Global tree numbers are estimates with uncertainties due to data gaps, land‑use change and differing definitions of what counts as a tree; human activities such as deforestation and reforestation continually change totals, so snapshots must be interpreted carefully and updated as better data become available.
Takeaway
That there are more trees on Earth than stars in our galaxy is an evocative reminder of the scale of life on this planet and underscores the importance of protecting and restoring forests to preserve ecological function, climate stability and the many services trees provide to people and nature.