Three trillion: the latest estimate of the planet’s tree population, published in this issue of Nature (see page 201), exceeds the number of stars in the Milky Way. At more than 7 times the previous estimate of 400 billion, the figure is impressive, but it should not necessarily be taken as good news. The forest-density study — which combined satellite imagery with data from tree counts on the ground that covered more than 4,000 square kilometres — also estimated that 15 billion trees are cut down each year. And in the 12,000 years since farming began spreading across the globe, the number of trees on our planet has fallen by almost half.

SOURCE: T. W. CROWTHER ET AL. NATURE 525, 201–205 (2015). VISUALIZATION: JAN WILLEM TULP

SOURCE: T. W. CROWTHER ET AL. NATURE 525, 201–205 (2015). VISUALIZATION: JAN WILLEM TULP

SOURCE: T. W. CROWTHER ET AL. NATURE 525, 201–205 (2015). VISUALIZATION: JAN WILLEM TULP

SOURCE: T. W. CROWTHER ET AL. NATURE 525, 201–205 (2015)

SOURCE: T. W. CROWTHER ET AL. NATURE 525, 201–205 (2015)

SOURCE: T. W. CROWTHER ET AL. NATURE 525, 201–205 (2015)