Mariposa Grove in Yosemite National Park, California

© Orbon Alija/Getty Image

Warm light through an ancient forest. Arbor Day

On this last Friday of April, we're celebrating the importance of planting and preserving trees. The history of this day—Arbor Day—can be traced back to Nebraska in the early 1870s when a journalist, Julius Sterling Morton, editor of the Nebraska City News, used his public platform to highlight the ecological importance of trees. In 1872, he proposed a day for Nebraskans to plant trees, and thus, Arbor Day came into existence.

The giant sequoia, seen here, is an embodiment of the significance of trees. According to the US National Park Service, geological evidence shows that sequoias have one of the oldest lineages of any living thing on earth. Mariposa Grove in Yosemite National Park, pictured here, has hundreds of sequoias that can be as ancient as 3,500 years old.