BOULDER, Colo. — April 26 marks Arbor Day. People around the world celebrate the holiday by planting trees. The holiday started in Nebraska in 1872. More than 1 million plants were reportedly planted ...

TUCSON, Ariz. (KGUN) — Trees give us shade, they give us fruit and they give us life. But it takes a lot of work to keep our trees healthy. Friday was the start of the Arizona Community Tree Council’s ...

Scientists learn how to ascend and study the world’s tallest trees. Tree Climbing School at Dorena offers a demanding 4-day training to teach ecologists and scientists the skills they need to ascend ...

Vertical Voyages takes students upward to sleep in the trees at John Burroughs School. This story first appeared in the Outdoors newsletter. Click here to learn more and sign up. Sometimes, Jon ...