There may be more trees on Earth than stars in the Milky Way

Look up at a clear night sky and the stars feel limitless. Yet by one striking comparison, our own planet may out-number the galaxy. A 2015 study published in Nature, led by Yale ecologist Thomas Crowther, estimated there are about 3.04 trillion trees on Earth — roughly 422 trees for every person alive.

That figure dwarfed earlier guesses. The previously accepted estimate, based mostly on satellite imagery, was around 400 billion. By combining satellite data with ground counts from over 400,000 forest plots, the team revised the number upward by an order of magnitude.

Three trillion trees on one planet — against a galaxy of, at most, a few hundred billion stars.

The Milky Way is generally estimated to hold somewhere between 100 billion and 400 billion stars, the spread reflecting uncertainty about how many faint, low-mass stars hide in its reaches. Even at the high end, Earth’s trees appear to win the count, perhaps several times over.

It’s a humbling flip of scale. We treat the cosmos as the realm of the uncountable, but a single living planet — its forests, not yet vanished — can rival an entire galaxy. The catch: that tree count is falling fast, by an estimated 15 billion a year.