Supermodel Naomi Campbell plants a cocoa tree in Abuja Central Park and Botanical Gardens on July 11, 2008, in Abuja, Nigeria. The tree launched the Abuja Green Society's planting of one million trees in the federal capital territory. The goal of the planting was to make the city greener while bringing the community together and raising awareness of environmental issues.
(Photo: Dan Kitwood/Getty Images)
James Cameron attends the Blu-ray and DVD release tree-planting ceremony for Avatar, held on the 20th Century Fox Studios lot in Culver City on Earth Day, April 22, 2010. In addition to the film being the highest-grossing movie of all time, its marketing campaign involved a strong enviornmental focus.
(Photo: Noel Vasquez/Getty Images)
U.S. talk-show host Oprah Winfrey plants a tree with Kenyan Environmentalist Wangari Maathai (not pictured) during a tree planting and dedication ceremony commemorating the two-day "Be the Change" leadership conference, held at the Oprah Winfrey Leadership Academy for Girls in Henley-on-Klip, outside Johannesburg, in November 2008.
(Photo: REUTERS/Siphiwe Sibeko)
During a visit to the Thai city of Hua Hin in September 2010, superstar tennis player Rafael Nadal waters a tree as he takes part in a tree planting project in honor of Thai King Bhumibol Adulyadej's One Million Trees for the King campaign.
(Photo: Pornchia Kittiwongsakul/Getty Images)
Actress Rosario Dawson attends The Joyful Activist Club Tree Planting at Westminster Elementary School on April 2, 2011, in Venice, California.
(Photo:Valerie Macon/Getty Images)
Kate Middleton, Duchess of Cambridge
Britain's Prince William watches as his wife Kate, a.k.a Catherine, Duchess of Cambridge, wields a shovel to plant a tree at Rideau Hall in Ottawa, July 2, 2011.
(Photo: REUTERS/Lionel Hahn)
United States First Lady Michelle Obama, along with Yoriko Fujisaki, wife of the Ambassador of Japan to the United States, and local schoolchildren, commemorate the centennial anniversary of Tokyo's 1912 gift of cherry blossom trees to Washington, D.C. by planting a cherry blossom tree near the Tidal Basin in Washington on March 27, 2012.
(Photo: REUTERS/Gary Cameron)
Queen Elizabeth II of Britain is watched by gardener Norm Dunn and her husband, Prince Philip, as she plants a Black Sally gum tree on the grounds of Government House in Canberra, on March 14, 2006. The tree, a Eucalyptus stellulata, is called a Black Sally for the English weeping willow, or weeping sallow, and its black tree bark.
(Photo: REUTERS/Will Burgess)
The Dalai Lama
The Dalai Lama waters a newly planted tree in the garden of London's Clarence House on May 22, 2008.
(Photo: REUTERS/Alessia Pierdomenico)
Irish rock star Bono and children plant saplings during a tree planting ceremony at a landfill island in Tokyo on May 27, 2008.
(Photo: Toru Yamanaka/Getty Images)
Britain's Prince Charles and his wife, Camilla, Duchess of Cornwall, plant a tree at the Rio de Janeiro Botanic Garden on March 12, 2009.
(Photo: REUTERS/Fernando Soutello)
U.S. President Barack Obama plants a tree at Kenilworth Aquatic Gardens in Washington on April 21, 2009.
(Photo: REUTERS/Jason Reed)
Pope Benedict XVI
Pope Benedict XVI plants an olive tree with Israel's President Shimon Peres at the President's residence in Jerusalem on May 11, 2009.
(Photo: REUTERS/Rina Castelnuovo)
Britain's Prince Harry smiles as he helps plant a tree during an official naming of the British Garden at Hanover Square in New York, on May 29, 2009.