In honor of Earth Day, we’ve rounded up some of our favorite National Geographic stories on people making a big impact around the world through trees—planting them, climbing them, and advocating for them.

Here are five stories celebrating trees and the people who love them.

This Teenager Has Planted More Than 14 Billion Trees

Felix Finkbeiner has been working steadily since he was a child planting trees to combat the effects of climate change. He spoke to the United Nations General Assembly when he was just nine years old about the inaction he saw from adults who were supposed to be preserving the planet for future generations.

Realizing that he and his peers would be living through the consequences of their passivity, Finkbeiner started the environmental group Plant-for-the-Planet, which then partnered with the UN’s Billion Tree campaign. Together, they have set a new planting goal of one trillion trees, or about 150 trees for every person on Earth.

A Man in India Planted a Forest Bigger Than Central Park

Funded in part by Kickstarter, "Forest Man" was directed by William Douglas McMaster and won Best Documentary for the American Pavilion Emerging Filmmaker Showcase at the Cannes Film Festival in 2014. The Short Film Showcase spotlights exceptional short videos created by filmmakers from around the web and selected by National Geographic editors. Learn more here.

Jadav Payeng has been working since 1979 to plant hundreds of trees to save his island, which is threatened by erosion.

Northeast India’s Majuli Island, the world’s largest river island, was becoming a barren wasteland due to climate change. The Brahmaputra River that flows around it was eroding its shores at a steadily increasing rate.

The island, home to 150,000 people, has lost over half its land mass to erosion since 1917. But Payeng, a modern-day Johnny Appleseed, is protecting it by turning it into an oasis with a forest larger than Central Park. The forest is now home to elephants, rhinos, tigers, and more, and Payeng must protect it from a new threat—the humans who want to use it for economic gain.

This Man Brought Flowering Cherry Trees to Washington, D.C.

View Images Cherry blossoms burst forth in pink every spring around the Tidal Basin in Washington, D.C. SEAN PAVONE PHOTO/GETTY IMAGES

David Fairchild, a food explorer working for the U.S. government in the early 1900s, worked to bring fruits and plants to the United States at a time when the country feared foreign species. He introduced peaches, avocados, mangoes—and came up with the idea for bringing Japanese cherry trees to America.

After seeing the trees in Japan and becoming enchanted by their beauty, Fairchild ordered some for his home near Chevy Chase, Maryland. So many people came to see the trees’ first bloom the following year that he gifted 300 of them to the city of Chevy Chase.

As Congress worked to beautify Washington, D.C., which wasn’t considered to be an attractive city at the time, Fairchild (along with folks like Eliza Scidmore) supported the popular idea that cherry trees could be planted around city’s Tidal Basin. With support from President and Mrs. Taft, who had just entered the White House and were looking for a way to build up diplomatic relations with Japan, thousands of trees were ordered.

The first attempt at shipping the trees failed because they were poorly packed and full of infestation. The second attempt succeeded, and the blossoms are still welcomed with joy every spring in D.C. over a hundred years later.

Villagers in Georgia Risk Their Lives for Christmas Trees

Nordmann firs, Europe’s preferred Christmas trees, grow in the forested valleys of Racha, a mountainous region of Georgia. But the process of harvesting the seeds from them is more akin to the Wild West than a holiday tradition.

The people who live in nearby villagers climb high up into the fir trees without equipment, often endangering their own lives during the fast-paced harvest, to gather the pinecones that grow at the top. The pinecones, which contain the firs’ seeds, are then shipped in big batches to companies that grow new trees for the Christmas season.

Even the highest paid laborers only make 90 cents per pound of Nordmann fir seeds, while the lowest make 16 cents per pound. In addition, “cone pirates” poach these valuable cones away from the company laborers.

While the climbers use the opportunity to make a small amount of money, critics say the safety of those harvesting the seeds needs to be a greater priority.

“If you think that [Christmas] is about the birth of Jesus Christ and people are dying to get the Christmas tree into your living rooms, this is really insane,” adds Michael Kraus, the German safety coordinator and harvest manager for Fair Trees.

One Man Plans to Transform London Into One Big Park

View Images The oldest of the city's eight Royal Parks, St. James's Park offers lovely views. Photograph by Simon Roberts, Nat Geo Image Collection

National Geographic explorer and self-described “guerrilla photographer” Daniel Raven-Ellison isn’t necessarily planting trees himself. He has, however, noticed the millions of trees growing throughout his home city of London and is using them as part of his argument to redefine the city as a national park.