This year's Earth Day, on April 22, celebrates the beauty and many benefits of trees, from the habitat they create to the air we breathe. Earth Day organizers are also announcing the ambitious goal of planting 7.8 billion—one for every person on the planet—by 2020. (See stunning pro photos of trees.)

Last year, National Geographic photographer Erika Larsen issued a call to the Your Shot community to share their favorite images of trees.

"Nearly every person in the world has a relationship to trees," Larsen wrote. "They provide a vital balance for many aspects of our existence."

Many people have a tree that is especially meaningful in their lives, and Larsen asked the community to share those memories through photography.

Here, we assembled