More than 3 trillion trees now grow on Earth, seven times more than scientists previously thought. But it's also trillions fewer than there used to be, a new study concludes. A United ...

Look up at the night sky and you might feel dwarfed by the glimmer of countless stars. Now shift that view downward, press your mind to the ground and the green world under your feet—and you’ll find ...

Trees are the “lungs” of the Earth — leafy organisms that produce the oxygen we breathe in every day and cycle the carbon dioxide we breathe out. But despite trees’ vital importance to human survival, ...